Porous paper-based finishing material and preparation method thereof

Abstract

The present invention provides a porous paper-based decorative material and a preparation method thereof. The preparation method comprises: S100, separately preparing a porous paper base, an anti-mildew coating, and a decorative coating; S200, applying the anti-mildew coating to the paper base and performing a first heat treatment to form an anti-mildew layer on the porous paper base; S300, applying the decorative coating to the anti-mildew layer and performing a second heat treatment to form a decorative layer on the anti-mildew layer, thereby obtaining the porous paper-based decorative material. The porous paper base comprises hollow silica particles, the anti-mildew coating comprises chitosan, and the decorative coating comprises sodium alginate. The temperature of the first heat treatment is 80°C to 90°C, and the temperature of the second heat treatment is 100°C to 110°C. The present invention can produce a porous paper-based decorative material with good mechanical strength and resistance to mildew.

Description

Technical Field

[0001] The present invention relates to the technical field of papermaking, and in particular to a porous paper-based finishing material and a preparation method thereof. Background Art

[0002] In interior decoration projects, paper-based finishing materials are an important base material, used in a variety of applications, including wall decoration and furniture veneer. Besides wallpaper, decorative paper is also used in low- and high-pressure boards used in furniture and cabinets, fireproof boards, and flooring to enhance the aesthetics of the product.

[0003] Porous paper-based decorative materials are typically manufactured through processes such as pulping, papermaking, and pressing. The two most important performance indicators for porous paper-based decorative materials in the industry are their mechanical strength and mildew and moisture resistance. Improving the mechanical strength and mildew and moisture resistance of porous paper-based decorative materials has long been a technical challenge for those skilled in the art. Summary of the Invention

[0004] One of the problems solved by the present invention is how to provide a porous paper-based finishing material with high mechanical strength and good mildew and moisture resistance.

[0005] In order to solve at least one of the above problems, the present invention provides a method for preparing a porous paper-based finishing material, the preparation method comprising:

[0006] S100, preparing a porous paper base, an anti-mildew coating, and a decorative coating respectively;

[0007] S200, applying the anti-mildew coating to the paper base layer, and performing a first heat treatment to form an anti-mildew layer on the porous paper base layer;

[0008] S300, applying the decorative coating to the anti-mildew layer and performing a second heat treatment to form a decorative layer on the anti-mildew layer, and obtaining the porous paper-based finishing material;

[0009] Wherein, the porous paper base layer comprises hollow silica particles, the anti-mildew coating comprises chitosan, and the decorative coating comprises sodium alginate.

[0010] In any of the above technical solutions, the porous paper substrate is prepared by the following steps:

[0011] S111, mixing raw materials including a wet strength agent, aluminum sulfate, cationic polyacrylamide, hollow silica particles, bleached softwood pulp, and bleached hardwood pulp to obtain a pulp;

[0012] S112, placing the slurry on a screen to make paper sheets to obtain wet paper sheets;

[0013] S113, pressing, drying and calendering the wet paper sheet to obtain the porous paper base layer.

[0014] In any of the above technical solutions, in S111, the mass ratio of wet strength agent: aluminum sulfate: cationic polyacrylamide: hollow silica particles: bleached coniferous pulp: bleached hardwood pulp is (3-4): (4-5): (5-6): (12-16): (15-25): 100.

[0015] In any of the above technical solutions, in S111, the beating degree of the slurry is 30°SR to 45°SR, and the wet weight is 2.0g to 3.0g.

[0016] In any of the above technical solutions, the anti-mildew coating is prepared by the following steps:

[0017] S121, mixing raw materials including a surfactant, an emulsifier, a wetting agent, a defoaming agent, oxalic acid, chitosan, potassium sorbate, polyethylene glycol, a water-soluble acrylate, and water to obtain a first mixture;

[0018] S122. Heat the first mixture to 45° C. to 55° C., and ultrasonically disperse the mixture for 20 to 30 minutes under heat preservation conditions to obtain the anti-mildew coating.

[0019] In any of the above technical solutions, in S121, the mass ratio of surfactant: emulsifier: wetting agent: defoaming agent: oxalic acid: chitosan: potassium sorbate: polyethylene glycol: water-soluble acrylate: water = (0.2-1): (0.5-1.5): (0.5-1.5): (0.5-1.5): (2-4): (6-8): (8-10): (10-12): (20-30): 100.

[0020] In any of the above technical solutions, the decorative coating is prepared by the following steps:

[0021] S131, mixing raw materials including a color regulator, a gloss regulator, sodium alginate, polyacrylamide, a water-soluble acrylate, and water to obtain a second mixture;

[0022] S132, ultrasonically dispersing the second mixture for 20 to 30 minutes to obtain the decorative coating.

[0023] In any of the above technical solutions, in S131, the mass ratio of color regulator: gloss regulator: sodium alginate: polyacrylamide: water-soluble acrylate: water = (2-8): (2-8): (4-6): (16-20): (20-30): 100.

[0024] In any of the above technical solutions, the temperature of the first heat treatment is 80°C to 90°C, and the temperature of the second heat treatment is 100°C to 110°C.

[0025] The present invention also provides a porous paper-based finishing material, which is obtained by using the preparation method described in any of the above technical solutions.

[0026] Beneficial effects

[0027] The present invention provides a method for preparing a porous paper-based finishing material. The method comprises separately preparing a porous paper base, an anti-mildew coating, and a decorative coating; then applying the anti-mildew coating to the paper base and performing a first heat treatment to form an anti-mildew layer on the porous paper base; and finally applying the decorative coating to the anti-mildew layer and performing a second heat treatment to form a decorative layer on the anti-mildew layer, thereby obtaining the porous paper-based finishing material. It should be noted that the porous paper base of the present invention comprises hollow silica particles, the anti-mildew coating comprises chitosan, and the decorative coating comprises sodium alginate. The hollow silica particles can improve the mechanical strength and fireproofing and heat-insulating properties of the porous paper base, and the electrostatic effect between chitosan and sodium alginate can uniformly apply the anti-mildew coating and the decorative coating, forming a uniform, dense, and uniformly thick anti-mildew layer and decorative layer. Thus, the porous paper-based finishing material obtained by the present invention has excellent mechanical strength, good anti-mildew and moisture-resistant effects, and good fireproofing and heat-insulating properties. Its thickness is uniform, and the paper surface is smooth and shiny. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the following is a detailed description of the specific embodiments of the present invention.

[0029] Unless otherwise specified, the reagents and raw materials used in the present invention can be purchased from commercial sources. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0030] Paper-based finishing materials are important decoration base materials, which can be used in various scenarios such as wall decoration and furniture veneer. The two performance indicators that are most valued for porous paper-based finishing materials in this field are their mechanical strength and mildew and moisture resistance. Take wallpaper as an example. As a decorative material widely used in modern interior decoration, compared with traditional interior decoration materials such as coatings and wall paints, wallpaper has the advantages of safety, environmental protection, easy construction, and rich and diverse colors and patterns. However, wallpaper itself is not wear-resistant, easily scratched and damaged, easily affected by moisture and mold, and easy to breed bacteria. Therefore, the present invention is committed to providing a paper-based finishing material with high mechanical strength and good mildew and moisture resistance, which is particularly suitable as interior decoration materials such as wallpaper.

[0031] An embodiment of the present invention provides a method for preparing a porous paper-based finishing material, the method comprising:

[0032] S100, preparing a porous paper base, an anti-mildew coating, and a decorative coating respectively;

[0033] S200, applying the anti-mildew coating to the paper base layer, and performing a first heat treatment to form an anti-mildew layer on the porous paper base layer;

[0034] S300, applying the decorative coating to the anti-mildew layer and performing a second heat treatment to form a decorative layer on the anti-mildew layer, and obtaining the porous paper-based finishing material;

[0035] Wherein, the porous paper base layer comprises hollow silica particles, the anti-mildew coating comprises chitosan, and the decorative coating comprises sodium alginate.

[0036] The porous paper substrate is mainly manufactured through processes such as pulping, papermaking, and pressing. Those skilled in the art can select and adjust the equipment, raw materials, and process parameters used in pulping, papermaking, and pressing according to actual needs.

[0037] Among them, pulping is a key process in the papermaking industry. This step separates the fibers from the plant fiber raw materials to obtain paper pulp. The pulping step of the present invention can be carried out by mechanical method, chemical method or chemical mechanical method. The papermaking step uses a bamboo curtain-type mesh trough specially used for papermaking to scoop out a certain amount of paper pulp, and then swings the mesh trough back and forth or left and right to arrange the pulp fibers in a certain direction to form a paper layer of uniform thickness, i.e., a wet paper sheet. The pressing process squeezes the wet paper through a press, and its function is to remove excess water in the paper layer and increase the dryness of the paper. The pressure and speed in the pressing process can be selected and adjusted by those skilled in the art according to actual needs.

[0038] In some embodiments of the present invention, the porous paper substrate is prepared by the following steps:

[0039] S111, mixing raw materials including a wet strength agent, aluminum sulfate, cationic polyacrylamide, hollow silica particles, bleached softwood pulp, and bleached hardwood pulp to obtain a pulp;

[0040] S112, placing the slurry on a screen to make paper sheets to obtain wet paper sheets;

[0041] S113, pressing, drying and calendering the wet paper sheet to obtain the porous paper base layer.

[0042] Among them, the role of the wet strength agent is to significantly improve the wet strength of the paper without changing the dry strength of the paper, so that the paper can still maintain good physical properties in a humid environment. Preferably, the present invention can select PAE wet strength agent. The addition of aluminum sulfate can significantly improve the hardness and strength of the paper, enhance the water resistance of cellulose, and thus improve the quality and durability of the paper. In addition, the use of aluminum sulfate can improve the gloss and smoothness of the paper. Cationic polyacrylamide reduces surface tension through the carboxyl groups in its molecular chain, allowing fibers or fillers to be better dispersed in water, thereby improving the uniformity and quality of the paper. Hollow silica particles are used as fillers, which can improve the mechanical strength and fireproof and heat-insulating effects of paper.

[0043] Preferably, in S111, the mass ratio of wet strength agent: aluminum sulfate: cationic polyacrylamide: hollow silica particles: bleached coniferous pulp: bleached hardwood pulp is (3-4): (4-5): (5-6): (12-16): (15-25): 100.

[0044] Further preferably, in S111, the mass ratio of wet strength agent: aluminum sulfate: cationic polyacrylamide: hollow silica particles: bleached coniferous pulp: bleached hardwood pulp is 3:4:6:15:25:100.

[0045] Preferably, in S111, the beating degree of the slurry is 30°SR to 45°SR, and the wet weight is 2.0 g to 3.0 g.

[0046] Further preferably, in S111, the beating degree of the slurry is 35°SR to 40°SR, and the wet weight is 2.4 g to 2.8 g.

[0047] Preferably, the hollow silica particles are prepared by the following steps:

[0048] S111a, mixing the chitosan in ethanol and water at a mass ratio of chitosan: ethanol: water = (8-12): (25-30): 100, and adjusting the pH to 3-4 by adding acid to obtain solution A;

[0049] S111b, adding silicon tetrachloride dropwise to the solution A with stirring according to the amount of water added in S111a at a mass ratio of silicon tetrachloride:water=(4-8):100, continuing stirring for 1 to 1.5 hours after the addition is complete, adjusting the pH to 11-12 with alkali, and allowing to stand for 12 to 15 hours to obtain a silica sol containing chitosan;

[0050] S111c, soaking the silica sol in ethanol and aging for 24 to 48 hours, taking it out and sending it into a vacuum reactor filled with ethanol, and keeping it warm and pressurized for 2 to 3 hours at a temperature of 260° C. to 270° C. and a pressure of 6.7 MPa to 7.0 MPa. After the treatment, cooling and releasing the pressure, separating, washing with water, and drying to obtain the hollow silica particles.

[0051] The purpose of adopting the above steps is to prepare loose, porous, hollow, small-sized, and uniformly distributed silica particles. In general, the above steps use a sol-gel method to prepare nano-silica. The improvement made on the basis of the existing sol-gel method is that chitosan is added to the hydroalcoholic liquid used to prepare the sol solution. The hydroalcoholic liquid used to prepare nano-silica by the sol-gel method requires the addition of an acidic catalyst, and chitosan has low solubility in water under acidic conditions and exists almost in a granular state. Subsequently, in order to prepare nano-silica, it is also necessary to add an alkaline catalyst, and chitosan has increased solubility in water under alkaline conditions. Therefore, in the process of adding silicon tetrachloride to the A solution, stirring, and adding alkali to adjust the pH value, a silica sol containing chitosan can be formed, and the chitosan is evenly distributed in the silica sol. Subsequently, ethanol is used as a solvent and supercritical drying is performed to prepare silica in an aerogel form. Furthermore, chitosan, evenly distributed within the silica sol, undergoes thermal decomposition at temperatures between 260°C and 270°C. The resulting organic matter and water are extracted by supercritical ethanol, forming porous, hollow silica particles with a small, uniform particle size distribution. The three-dimensional, porous nature of these hollow silica particles improves the fireproofing and thermal insulation properties of porous paper substrates.

[0052] In some embodiments of the present invention, the anti-mildew coating is prepared by the following steps:

[0053] S121, mixing raw materials including a surfactant, an emulsifier, a wetting agent, a defoaming agent, oxalic acid, chitosan, potassium sorbate, polyethylene glycol, a water-soluble acrylate, and water to obtain a first mixture;

[0054] S122. Heat the first mixture to 45° C. to 55° C., and ultrasonically disperse the mixture for 20 to 30 minutes under heat preservation conditions to obtain the anti-mildew coating.

[0055] Preferably, in some embodiments of the present invention, in S121, the mass ratio of surfactant: emulsifier: wetting agent: defoaming agent: oxalic acid: chitosan: potassium sorbate: polyethylene glycol: water-soluble acrylate: water = (0.2-1): (0.5-1.5): (0.5-1.5): (0.5-1.5): (2-4): (6-8): (8-10): (10-12): (20-30): 100.

[0056] Further preferably, in some embodiments of the present invention, in S121, the mass ratio of surfactant: emulsifier: wetting agent: defoaming agent: oxalic acid: chitosan: potassium sorbate: polyethylene glycol: water-soluble acrylate: water = 0.5:0.5:1:1:3:8:10:12:25:100.

[0057] In some embodiments of the present invention, the decorative coating is prepared by the following steps:

[0058] S131, mixing raw materials including a color regulator, a gloss regulator, sodium alginate, polyacrylamide, a water-soluble acrylate, and water to obtain a second mixture;

[0059] S132, ultrasonically dispersing the second mixture for 20 to 30 minutes to obtain the decorative coating.

[0060] Preferably, in some embodiments of the present invention, in S131, the mass ratio of color regulator: glossiness regulator: sodium alginate: polyacrylamide: water-soluble acrylate: water = (2-8): (2-8): (4-6): (16-20): (20-30): 100.

[0061] Further preferably, in some embodiments of the present invention, in S131, the mass ratio of color regulator: glossiness regulator: sodium alginate: polyacrylamide: water-soluble acrylate: water is 6:2:4:16:22:100.

[0062] The temperature of the first heat treatment is 80°C to 90°C, and the temperature of the second heat treatment is 100°C to 110°C.

[0063] In the present invention, the type and type of auxiliary materials have no impact on the achievement of the invention's objectives and can be freely selected by those skilled in the art. In the present invention, the surfactant is specifically sodium dodecylbenzenesulfonate, the emulsifier is specifically a silicone oil emulsifier, the wetting agent is specifically dioctyl sodium sulfosuccinate, and the defoamer is specifically a polyether defoamer. The gloss modifier is specifically mica powder.

[0064] The above steps are adopted because chitosan and potassium sorbate have good antibacterial and mildew-proof effects. Polyacrylamide and / or water-soluble acrylate, as polymer resin materials, have good wear resistance and waterproof and moisture-proof properties. In addition, the temperature of the indoor environment where the wallpaper is located will vary greatly with the change of seasons, and the air permeability of the resin adhesive surface layer is extremely poor, which makes local areas of the wallpaper prone to bubbling, affecting the decorative effect. Once bubbling occurs on the wallpaper surface, it will also affect the waterproof and moisture-proof effect of the wallpaper. In order to reduce the possibility of bubbling, it is crucial to improve the tightness and uniformity of the bond between the mildew-proof layer and the decorative layer. In order to ensure a tight and uniform combination between the anti-mildew layer and the decorative layer, the present invention utilizes the electrostatic effect between chitosan and sodium alginate, adds chitosan to the anti-mildew layer, and then after a first heat treatment at 80°C to 90°C, the anti-mildew layer is in a semi-dried but not completely dried state. Then, sodium alginate is added to the decorative layer applied subsequently. The electrostatic effect of the positive and negative charges between chitosan and sodium alginate allows the decorative layer to be more evenly applied on the anti-mildew layer. After a second heat treatment at 100°C to 110°C, the porous paper-based finishing material is completely dried.

[0065] Example 1

[0066] This embodiment provides a porous paper-based finishing material, which is prepared by the following steps:

[0067] S1. Mix chitosan in ethanol and water at a mass ratio of chitosan: ethanol: water = 10:25:100, and adjust the pH to 3-4 by adding acid to obtain solution A;

[0068] S2. Add silicon tetrachloride dropwise to solution A at a mass ratio of silicon tetrachloride to water of 8:100, depending on the amount of water added in S1, while stirring simultaneously. Continue stirring for 1.5 hours after the addition is complete, add alkali to adjust the pH to 11-12, and let it stand for 15 hours to obtain a silica sol containing chitosan;

[0069] S3, soaking the silica sol in ethanol and aging it for 48 hours, taking it out and putting it into a vacuum reactor filled with ethanol, and keeping it warm and pressurized for 2 hours at a temperature of 260° C. to 270° C. and a pressure of 6.7 MPa to 7.0 MPa. After the treatment, cooling and releasing the pressure, separating, washing with water, and drying to obtain hollow silica particles;

[0070] S4. Mixing raw materials including a surfactant, an emulsifier, a wetting agent, a defoaming agent, oxalic acid, chitosan, potassium sorbate, polyethylene glycol, a water-soluble acrylate, and water in a mass ratio of surfactant: emulsifier: wetting agent: defoaming agent: oxalic acid: chitosan: potassium sorbate: polyethylene glycol: water-soluble acrylate: water = 0.5:0.5:1:1:3:8:10:12:25:100 to obtain a first mixture; heating the first mixture to 50° C. and ultrasonically dispersing it under heat preservation conditions for 20 minutes to obtain an anti-mildew coating;

[0071] S6. Mixing raw materials including a color regulator, a gloss regulator, sodium alginate, polyacrylamide, a water-soluble acrylate, and water in a mass ratio of 6:2:4:16:22:100 to obtain a second mixture; and ultrasonically dispersing the second mixture for 20 minutes to obtain a decorative coating.

[0072] S7. Mixing raw materials including a wet strength agent, aluminum sulfate, cationic polyacrylamide, hollow silica particles, bleached softwood pulp, and bleached hardwood pulp in a mass ratio of 3:4:6:15:25:100 to obtain a pulp; the pulp has a beating degree of 35°SR and a wet weight of 2.4 g; placing the pulp on a screen to obtain a wet paper sheet; and pressing, drying, and calendering the wet paper sheet to obtain a porous paper base.

[0073] S8. Apply a thin coat of the anti-mildew coating to the paper base layer at a mass ratio of anti-mildew coating: decorative coating = 1:1, and perform a first heat treatment at a temperature of 80°C to 90°C until the anti-mildew layer is in a semi-dry but not completely dry state, so as to form an anti-mildew layer on the porous paper base layer; apply the decorative coating to the anti-mildew layer, and perform a second heat treatment at a temperature of 100°C to 110°C until the anti-mildew layer and the decorative layer are completely dry, so as to form a decorative layer on the anti-mildew layer, and obtain a porous paper-based finishing material.

[0074] Example 2

[0075] This embodiment provides a porous paper-based finishing material, which is prepared by the following steps:

[0076] S1. Mixing raw materials including a surfactant, an emulsifier, a wetting agent, a defoaming agent, oxalic acid, chitosan, potassium sorbate, polyethylene glycol, a water-soluble acrylate, and water in a mass ratio of surfactant: emulsifier: wetting agent: defoaming agent: oxalic acid: chitosan: potassium sorbate: polyethylene glycol: water-soluble acrylate: water = 0.5:0.5:1:1:3:8:10:12:25:100 to obtain a first mixture; heating the first mixture to 50° C. and ultrasonically dispersing it under heat preservation conditions for 20 minutes to obtain an anti-mildew coating;

[0077] S2. Mixing raw materials including a color regulator, a gloss regulator, sodium alginate, polyacrylamide, a water-soluble acrylate, and water in a mass ratio of 6:2:4:16:22:100 to obtain a second mixture; and ultrasonically dispersing the second mixture for 20 minutes to obtain a decorative coating.

[0078] S3. Mixing raw materials including a wet strength agent, aluminum sulfate, cationic polyacrylamide, hollow silica particles, bleached softwood pulp, and bleached hardwood pulp in a mass ratio of 3:4:6:15:25:100 to obtain a pulp; the pulp has a beating degree of 35°SR and a wet weight of 2.4 g; placing the pulp on a screen to obtain a wet paper sheet; and pressing, drying, and calendering the wet paper sheet to obtain a porous paper base; wherein the silica particles are commercially purchased nano-silica particles.

[0079] S8. Apply a thin coat of the anti-mildew coating to the paper base layer at a mass ratio of anti-mildew coating: decorative coating = 1:1, and perform a first heat treatment at a temperature of 80°C to 90°C until the anti-mildew layer is in a semi-dry but not completely dry state, so as to form an anti-mildew layer on the porous paper base layer; apply the decorative coating to the anti-mildew layer, and perform a second heat treatment at a temperature of 100°C to 110°C until the anti-mildew layer and the decorative layer are completely dry, so as to form a decorative layer on the anti-mildew layer, and obtain a porous paper-based finishing material.

[0080] Example 3

[0081] This embodiment provides a porous paper-based finishing material, which is prepared by the following steps:

[0082] S1. Mix chitosan in ethanol and water at a mass ratio of chitosan: ethanol: water = 10:25:100, and adjust the pH to 3-4 by adding acid to obtain solution A;

[0083] S2. Add silicon tetrachloride dropwise to solution A at a mass ratio of silicon tetrachloride to water of 8:100, depending on the amount of water added in S1, while stirring simultaneously. Continue stirring for 1.5 hours after the addition is complete, add alkali to adjust the pH to 11-12, and let it stand for 15 hours to obtain a silica sol containing chitosan;

[0084] S3, soaking the silica sol in ethanol and aging it for 48 hours, taking it out and putting it into a vacuum reactor filled with ethanol, and keeping it warm and pressurized for 2 hours at a temperature of 260° C. to 270° C. and a pressure of 6.7 MPa to 7.0 MPa. After the treatment, cooling and releasing the pressure, separating, washing with water, and drying to obtain hollow silica particles;

[0085] S4. Mixing raw materials including a surfactant, an emulsifier, a wetting agent, a defoaming agent, oxalic acid, potassium sorbate, polyethylene glycol, a water-soluble acrylate, and water in a mass ratio of surfactant: emulsifier: wetting agent: defoaming agent: oxalic acid: potassium sorbate: polyethylene glycol: water-soluble acrylate: water = 0.5:0.5:1:1:3:8:10:22:25:100 to obtain a first mixture; heating the first mixture to 50° C. and ultrasonically dispersing it under heat preservation conditions for 20 minutes to obtain a first coating;

[0086] S6. Mixing the raw materials including the color regulator, gloss regulator, polyacrylamide, water-soluble acrylate, and water in a mass ratio of color regulator: gloss regulator: polyacrylamide: water-soluble acrylate: water = 6:2:20:22:100 to obtain a second mixture; ultrasonically dispersing the second mixture for 20 minutes to obtain a second coating;

[0087] S7. Mixing raw materials including a wet strength agent, aluminum sulfate, cationic polyacrylamide, hollow silica particles, bleached softwood pulp, and bleached hardwood pulp in a mass ratio of 3:4:6:15:25:100 to obtain a pulp; the pulp has a beating degree of 35°SR and a wet weight of 2.4 g; placing the pulp on a screen to obtain a wet paper sheet; and pressing, drying, and calendering the wet paper sheet to obtain a porous paper base.

[0088] S8. Apply a thin coat of the first coating to the paper base layer at a mass ratio of first coating to second coating = 1:1, and perform a first heat treatment at a temperature of 80°C to 90°C until the first layer is in a semi-dry but not completely dry state, so as to form a first layer on the porous paper base layer; apply the second coating to the first layer, and perform a second heat treatment at a temperature of 100°C to 110°C until the first layer and the second layer are completely dry, so as to obtain a porous paper-based finishing material.

[0089] Performance Testing

[0090] The tensile strength of the papers obtained in Examples 1-3 was tested with reference to GB / T 12914-2008. The longitudinal tensile strengths of the papers obtained in Examples 1-3 were 33.5 N / 15 mm, 32.9 N / 15 mm, and 33.1 N / 15 mm, respectively. The wear rates of the papers obtained in Examples 1-3 were tested using a comprehensive material surface property tester. The wear rates of the papers obtained in Examples 1-3 were 2.04 mm, respectively. 3 / J, 2.76mm 3 / J, 2.69mm 3 / J. The thermal conductivity of the papers obtained in Examples 1-3 was tested using the hot box method according to GB / T 13475-2008. The thermal conductivity of the papers obtained in Examples 1-3 was 0.029 W / (m·K), 0.051 W / (m·K), and 0.032 W / (m·K), respectively. The antibacterial and mildew-proof properties of the papers obtained in Examples 1-3 were tested according to GB / T 21866-2008. The test strains included Aspergillus flavus, Aspergillus niger, Penicillium, and Soil mold. The papers obtained in Examples 1 and 2 showed no mildew growth within 6 months. The mildew growth area of the paper obtained in Example 3 was 0.4% after 6 months.

Claims

1. A method for preparing a porous paper-based facing material, characterized in that: The preparation method comprises: S100, preparing a porous paper base, an anti-mildew coating, and a decorative coating respectively; S200, applying the anti-mildew coating to the paper base layer, and performing a first heat treatment to form an anti-mildew layer on the porous paper base layer; S300, applying the decorative coating to the anti-mildew layer and performing a second heat treatment to form a decorative layer on the anti-mildew layer, and obtaining the porous paper-based finishing material; wherein the porous paper base comprises hollow silica particles, the anti-mildew coating comprises chitosan, and the decorative coating comprises sodium alginate; The anti-mildew coating is prepared by the following steps: S121, mixing raw materials including a surfactant, an emulsifier, a wetting agent, a defoaming agent, oxalic acid, chitosan, potassium sorbate, polyethylene glycol, a water-soluble acrylate, and water to obtain a first mixture; S122, heating the first mixture to 45° C. to 55° C., and ultrasonically dispersing the mixture for 20 to 30 minutes under heat preservation conditions to obtain the anti-mildew coating; The decorative coating is prepared by the following steps: S131, mixing raw materials including a color regulator, a gloss regulator, sodium alginate, polyacrylamide, a water-soluble acrylate, and water to obtain a second mixture; S132, ultrasonically dispersing the second mixture for 20 to 30 minutes to obtain the decorative coating; The hollow silica particles are prepared by the following steps: S111a, mixing the chitosan in ethanol and water at a mass ratio of chitosan: ethanol: water = (8-12): (25-30): 100, and adjusting the pH to 3-4 by adding acid to obtain solution A; S111b, adding silicon tetrachloride dropwise to the solution A at a mass ratio of silicon tetrachloride to water = (4-8):100 according to the amount of water added in S111a, while stirring simultaneously, continuing stirring for 1 to 1.5 hours after the addition is complete, adding alkali to adjust the pH to 11-12, and allowing to stand for 12 to 15 hours to obtain a silica sol containing chitosan; S111c, soaking the silica sol in ethanol and aging for 24 to 48 hours, taking it out and sending it into a vacuum reactor filled with ethanol, and keeping it warm and pressurized for 2 to 3 hours at a temperature of 260° C. to 270° C. and a pressure of 6.7 MPa to 7.0 MPa. After the treatment, cooling and releasing the pressure, separating, washing with water, and drying to obtain the hollow silica particles.

2. The preparation method according to claim 1, characterized in that The porous paper substrate is prepared by the following steps: S111, mixing raw materials including a wet strength agent, aluminum sulfate, cationic polyacrylamide, hollow silica particles, bleached softwood pulp, and bleached hardwood pulp to obtain a pulp; S112, placing the slurry on a screen to make paper sheets to obtain wet paper sheets; S113, pressing, drying and calendering the wet paper sheet to obtain the porous paper base layer.

3. The preparation method according to claim 2, characterized in that In S111, the mass ratio of wet strength agent: aluminum sulfate: cationic polyacrylamide: hollow silica particles: bleached coniferous wood pulp: bleached hardwood wood pulp is (3-4): (4-5): (5-6): (12-16): (15-25):

100.

4. The preparation method according to claim 2, characterized in that In S111 , the slurry has a beating degree of 30°SR to 45°SR and a wet weight of 2.0 g to 3.0 g.

5. The preparation method according to claim 1, characterized in that In S121, the mass ratio of surfactant: emulsifier: wetting agent: defoaming agent: oxalic acid: chitosan: potassium sorbate: polyethylene glycol: water-soluble acrylate: water = (0.2-1): (0.5-1.5): (0.5-1.5): (0.5-1.5): (2-4): (6-8): (8-10): (10-12): (20-30):

100.

6. The preparation method according to claim 1, characterized in that In S131, the mass ratio of color regulator: gloss regulator: sodium alginate: polyacrylamide: water-soluble acrylate: water is (2-8): (2-8): (4-6): (16-20): (20-30):

100.

7. The preparation method according to any one of claims 1 to 6, characterized in that The temperature of the first heat treatment is 80°C to 90°C, and the temperature of the second heat treatment is 100°C to 110°C.

8. A porous paper-based facing material, characterized in that: The porous paper-based finishing material is obtained by the preparation method according to any one of claims 1 to 7.