Transparent super-hydrophobic cultural relic protection material and preparation method thereof

Abstract

The invention discloses a transparent super-hydrophobic cultural relic protection material and a preparation method thereof.The method comprises the steps that firstly, a hydrolyzed silane coupling agent is grafted to the surface of silicon dioxide, then amino of the hydrolyzed silane coupling agent reacts with carboxyl of chain fatty acid, chain alkyl is grafted to the surfaces of silicon dioxide particles, and the transparent super-hydrophobic cultural relic protection material is obtained. The prepared material has excellent super-hydrophobicity, the contact angle of water drops on the surface of a coating is large, the rolling angle of the water drops on the surface of the coating is small, the water drops are difficult to stay on the surface of the coating, and therefore water permeation is effectively prevented. Meanwhile, due to the transparency of the silicon dioxide particles and the chain fatty acid, the coating can keep high transparency, and the original color and pattern of the cultural relic cannot be shielded or changed. The silane coupling agent serves as a bridge for connecting the silicon dioxide particles and the chain fatty acid, the chemical bonding effect in the coating can be enhanced, the coating is not prone to aging and cracking, the material has the advantages of being good in high temperature resistance and ultraviolet light resistance, and therefore the preservation life of the cultural relics is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of functional coating development and relates to a transparent super-hydrophobic cultural relic protection material and a preparation method thereof. Background Art

[0002] Paper artifacts, as carriers of history and culture, are an important part of cultural heritage. They contain a large number of precious cultural historical materials and records, and are also one of the most difficult types of artifacts to preserve for a long time. Since the main components of paper artifacts are plant fibers such as cellulose, and the oxygen bridges in cellulose have the ability to attract H + The characteristics of cellulose, coupled with the presence of easily oxidized groups in the cellulose structure (such as CH2OH and -OH), make cellulose prone to a series of chemical reactions, which ultimately lead to the breakage of the cellulose chain. Therefore, during the preservation process, paper artifacts will be easily affected by environmental factors such as humidity and ultraviolet rays, causing chain breakage, resulting in reduced mechanical strength, breeding of bacteria and pests, and further damage such as yellowing, brittle fracture, and breakage, greatly reducing the preservation life and appreciation and research value.

[0003] Inspired by the super-hydrophobic properties of organisms such as lotus leaves and butterfly wings in nature, researchers have explored the possibility of implementing hydrophobic modification on the surface of paper documents, aiming to give these documents the function of self-cleaning. Low surface energy and unique surface roughness structure are the two key elements to achieve this performance. At present, a number of technologies have been applied to the preparation of super-hydrophobic coatings, including but not limited to layer-by-layer self-assembly technology, electrospinning technology, chemical vapor deposition, plasma treatment, sol-gel method, impregnation method, chemical etching and spraying methods. Among many methods, spraying is a simple and practical method that can prepare super-hydrophobic materials on a large scale. However, most of the existing super-hydrophobic coatings are added with nanoparticles. After spraying, it will affect the handwriting on the surface of paper documents, seriously affecting the visual sensation during reading, and excessive spraying may even cause the loss of important information recorded on the paper. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a transparent super-hydrophobic cultural relics protection material and a preparation method thereof, thereby solving the technical problem of poor transparency of the super-hydrophobic coating in the prior art.

[0005] The present invention is achieved through the following technical solutions: A method for preparing a transparent super-hydrophobic cultural relic protection material comprises the following steps: S1: adding a silane coupling agent to a mixture of an organic solvent and water, stirring and reacting, and obtaining a hydrolyzed silane coupling agent; S2: adding the hydrolyzed silane coupling agent to the organic dispersion of silicon dioxide particles, stirring for reaction, and obtaining silicon dioxide@silane coupling agent particles; S3: adding the silica@silane coupling agent particles into an organic solution of a chain fatty acid, wherein the carbon chain length of the chain fatty acid is 14 to 20, and stirring the reaction to obtain the transparent and removable super hydrophobic material.

[0006] Preferably, the silane coupling agent is added to a mixture of an organic solvent and water, and the volume ratio of the organic solvent to water and the silane coupling agent is (20-16):(4-1):(2-0.5).

[0007] Preferably, the ratio of the silane coupling agent to the silica particles is (2-0.5) mL: (1-3) g.

[0008] Preferably, in step S2, the reaction temperature of the hydrolyzed silane coupling agent and the silica particles is 25-65° C., and the reaction time is 4-8 h.

[0009] Preferably, the chain fatty acid is one of stearic acid, myristic acid, palmitic acid, pearly acid and arachidic acid.

[0010] Preferably, the ratio of the silicon dioxide@silane coupling agent particles to the chain fatty acid is (1~2):1.

[0011] Preferably, the reaction temperature of adding the silicon dioxide@silane coupling agent particles to the chain fatty acid is 30-60° C., and the reaction time is 2-3 h.

[0012] A transparent super-hydrophobic cultural relic protection material is prepared by the above method.

[0013] A transparent and removable super-hydrophobic coating is prepared by coating the above-mentioned transparent super-hydrophobic cultural relic protection material on the surface of a substrate.

[0014] The above-mentioned transparent and removable super-hydrophobic coating has a water contact angle of 153° to 160°. Compared with the prior art, the present invention has the following beneficial technical effects: The invention discloses a method for preparing a super-hydrophobic and transparent super-hydrophobic material, wherein the method hydrolyzes a silane coupling agent and grafts it on the surface of a silica particle, and then the amino group on the hydrolyzed silane coupling agent reacts with the carboxyl group on a chain fatty acid to graft a chain alkyl group on the surface of the silica particle. The material prepared by grafting the chain alkyl group on the surface of the silica particle has excellent super-hydrophobicity. The contact angle of water droplets on the coating surface is large and the rolling angle is small, so that it is difficult for water droplets to stay on the coating surface, thereby effectively preventing water penetration. At the same time, due to the transparency of the silica particles and the chain fatty acid, the coating can maintain a high transparency and will not block or change the original color and pattern of the cultural relics. As a bridge connecting the silica particles and the chain fatty acid, the silane coupling agent can enhance the chemical bonding inside the coating, so that the coating is not easy to age and crack, and the material has good high temperature resistance and the advantage of resisting ultraviolet light, thereby extending the preservation life of the cultural relics.

[0015] Furthermore, the silane coupling agent is added to a mixture of an organic solvent and water, wherein the volume ratio of the organic solvent to water and the silane coupling agent is (20-16):(4-1):(2-0.5), so that the silane coupling agent can be fully hydrolyzed.

[0016] Furthermore, the ratio of the silane coupling agent to the silica particles is (2-0.5) mL: (1-3) g, which can graft -NH2 groups on the surface of the silica. Furthermore, in step S2, the reaction temperature of the hydrolyzed silane coupling agent and the silica particles is 25-65° C., and the reaction time is 4-8 h, so that the silane coupling agent and the silica can fully react.

[0017] Furthermore, the chain fatty acid is one of stearic acid, myristic acid, palmitic acid, pearl fatty acid, and arachidic acid, which can graft long-chain fatty acids onto the surface of the silica@silane coupling agent particles to reduce surface activation energy.

[0018] Furthermore, the ratio of the silica@silane coupling agent particles to the chain fatty acid is (1-2):1, so that the silica@silane coupling agent particles and the chain fatty acid can fully react.

[0019] Furthermore, the reaction temperature of adding the silicon dioxide@silane coupling agent particles to the chain fatty acid is 30-60° C. and the reaction time is 2-3 h, so that the silicon dioxide@silane coupling agent particles and the chain fatty acid can fully react. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A schematic diagram of a process for preparing a transparent super-hydrophobic cultural relics protection material in the present invention; Figure 2 The super depth of field images of the coatings obtained by spraying the materials prepared in Examples 1 to 3 of the present invention on paper documents; wherein, Figures (a1) and (a2) are super depth of field images of the original paper documents, Figures (b1) and (b2) are super depth of field images of SA:SiO2@KH550=1:1, Figures (c1) and (c2) are super depth of field images of SA:SiO2@KH550=1:2, and Figures (d1) and (d2) are super depth of field images of SA:SiO2@KH550=1:4; Figure 3 The SEM images of the coatings obtained by spraying the materials prepared in Examples 1 to 3 of the present invention on paper documents; wherein, Figures (a1) and (a2) are SEM images of the original paper documents, Figures (b1) and (b2) are SEM images of SA:SiO2@KH550=1:1, Figures (c1) and (c2) are SEM images of SA:SiO2@KH550=1:2, and Figures (d1) and (d2) are SEM images of SA:SiO2@KH550=1:4; Figure 4 The effect of the super-hydrophobic coating on the surface of paper documents and its contact angle before and after removal; (a1), (b1), and (c1) respectively show the SEM images at different magnifications before the coating is removed, while (a2), (b2), and (c2) correspond to the SEM images after the coating is removed; Figure 5 The contact angles of paper documents under different aging treatment conditions are shown; Figure 6 Scans of paper documents before and after spraying. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0023] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0024] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0025] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0026] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0027] like Figure 1 As shown, the present invention provides a method for preparing a transparent super-hydrophobic cultural relic protection material, comprising the following steps: (1) Drying the silica particles in an oven to pre-treat them to effectively remove the adsorbed moisture; The silicon dioxide is one of quartz, cristobalite, tridymite, and amorphous silicon dioxide. The mass of silicon dioxide is 1-3 g. During the drying pretreatment, the temperature is 100-150 °C and the time is 10-20 h. (2) In organic solvent A, magnetically stirring the pretreated silica at room temperature to fully disperse the silica; The ratio of silica to organic solvent A is (1-3) g: (60-120) mL, and the rotation speed is 300-500 r / min; (3) adding a silane coupling agent to a mixture of organic solvent A and water for hydrolysis at room temperature; The silane coupling agent is one of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane; the volume ratio of the organic solvent to water and the silane coupling agent is (20-16):(4-1):(2-0.5); (4) In an organic solvent A, the silane coupling agent hydrolyzed in step (3) and the silicon dioxide dispersion in step (2) are uniformly mixed and subjected to magnetic stirring reaction and then dried to prepare silicon dioxide@silane coupling agent particles; The reaction temperature is 25-65°C, the reaction time is 4-8 h, and the rotation speed is 300-500 r / min; finally, the product is placed in an oven at 100-150°C for drying for 10-12 h, and the solidified sample is taken out and ground into powder to obtain silica@silane coupling agent particles.

[0028] (5) In organic solvent A, C 14 -C 20 The long-chain fatty acid is used as a modifier, which is uniformly mixed with the silica@silane coupling agent particles in step (3) and subjected to magnetic stirring. After the reaction is complete, it is sprayed on the surface of the paper document using a spray gun to construct a super-hydrophobic coating.

[0029] C 14 -C 20 The long-chain fatty acid is one of stearic acid, myristic acid, palmitic acid, pearly fatty acid, and arachidic acid; the mass ratio of the long-chain fatty acid to the silica@silane coupling agent particles is preferably 1:(1-2), the reaction temperature is 30-60 °C, the reaction time is 2-3 h, and the rotation speed is 300-500 r / min.

[0030] When preparing the coating, a spraying method can be used, specifically: pour the prepared transparent and removable super-hydrophobic material into a spray gun, spray it evenly on the surface of the paper document, spray 2 to 3 times, put the sprayed paper document into an oven at 30 to 50°C for drying, and control the distance between the spray gun and the paper to about 8 to 12 cm.

[0031] The raw materials of the present invention are safe, non-toxic, easy to obtain, widely available and low in cost; the preparation process of the present invention is simple and can be mass-produced; the super-hydrophobic coating prepared by the present invention has excellent super-hydrophobicity, thermal stability, and UV resistance, and has certain removability, which complies with the principle of "restoring the old as the old" of cultural relics.

[0032] The present invention proposes a highly transparent removable super-hydrophobic coating for preventive protection of paper cultural relics and a preparation method thereof, and the specific steps are as follows: First, the SiO2 particles are placed in an oven for pretreatment to remove moisture. Then, the pretreated SiO2 particles are dispersed in anhydrous ethanol and magnetically stirred at room temperature to ensure their uniform distribution. Then, the silane coupling agent is added to the mixture of anhydrous ethanol and deionized water and allowed to stand for a period of time to complete the hydrolysis process. Subsequently, the hydrolyzed silane coupling agent solution is slowly dripped into the ethanol solution containing the SiO2 particles and stirred again with a magnetic stirrer to ensure the effective combination of the two. After stirring, the mixture is dried to finally obtain SiO2@silane coupling agent composite particles.

[0033] Next, the composite particles and long-chain fatty acids are added to anhydrous ethanol and further treated by magnetic stirring to fully mix the two. The mixed solution is transferred to a spray gun, and the distance between the spray gun and the surface of the paper cultural relic to be treated is adjusted to about 10 cm, and the document surface is evenly sprayed. After spraying, the paper is placed in an oven at 50 ° C for drying to solidify the coating and finally form a modified super-hydrophobic paper document. When removing the coating, only an organic solvent, such as ethanol, needs to be sprayed.

[0034] The super-hydrophobic coating developed by the present invention not only exhibits excellent super-hydrophobic performance, thermal stability and UV resistance, but also has good removability, strictly following the basic principle of "repairing the old as it is" in the field of cultural relics restoration. In addition, the coating technology is not limited to the protection of paper cultural relics, but also has the potential to expand to a wider range of cultural heritage protection fields.

[0035] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0036] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0037] Example 1 A method for preparing a transparent super-hydrophobic cultural relic protection material comprises the following steps: (1) Dry 1.0 g of 30 nm amorphous silicon dioxide in an oven at 120 °C for 12 h. (2) Add the dried amorphous silica to 60 mL of anhydrous ethanol solution and magnetically Stir vigorously for 1 h; (3) Add 1 mL of 3-aminopropyltriethoxysilane to a mixed solution of 18 mL of anhydrous ethanol and 2 mL of deionized water and allow to hydrolyze for 1 h. (4) The hydrolyzed 3-aminopropyltriethoxysilane solution was added dropwise to the silica solution in step (1), stirred at 65°C and 500 r / min for 4 h, and then dried in a 120°C forced air drying oven for 12 h. The obtained powder was ground and recorded as silica@3-aminopropyltriethoxysilane. (5) 0.1 g of stearic acid and 0.1 g of silica@3-aminopropyltriethoxysilane in step (4) were added to 30 mL of anhydrous ethanol solution and stirred at 50 °C for 2 h to obtain a transparent and removable superhydrophobic material.

[0038] The super-hydrophobic material was poured into a spray gun and sprayed on the paper document from left to right three times. The distance between the spray gun and the paper was controlled at about 10 cm. The sprayed paper was placed in a 50°C oven for drying, thereby forming a super-hydrophobic coating on the surface of the paper document.

[0039] Example 2 The difference from Example 1 is that the mass of silicon dioxide@3-aminopropyltriethoxysilane added in step (5) is 0.2 g.

[0040] Example 3 The difference from Example 1 is that the mass of silicon dioxide@3-aminopropyltriethoxysilane added in step (5) is 0.4 g.

[0041] Example 4 A method for preparing a transparent super-hydrophobic cultural relic protection material comprises the following steps: (1) Dry 1.5 g of 30 nm amorphous silicon dioxide in an oven at 120 °C for 12 h; (2) Add the dried amorphous silica to 80 mL of water-ethanol solution and magnetically Stir vigorously for 1 h.

[0042] (3) Add 1 mL of 3-aminopropyltriethoxysilane to a mixed solution of 18 mL of anhydrous ethanol and 2 mL of deionized water and allow to hydrolyze for 1 h. (4) The hydrolyzed 3-aminopropyltriethoxysilane solution was added dropwise to the silica solution in step (1), stirred at 65 and 500 r / min for 4 h, and then dried in a 120° C. air drying oven for 12 h. The obtained powder was ground and recorded as silica@3-aminopropyltriethoxysilane. (5) 0.1 g of myristic acid and 0.1 g of silica@3-aminopropyltriethoxysilane in step (4) were added to 30 mL of anhydrous ethanol solution and stirred at 50 °C for 2 h to obtain a transparent and removable superhydrophobic material.

[0043] The super-hydrophobic material was poured into a spray gun and sprayed on the paper document from left to right three times. The distance between the spray gun and the paper was controlled at about 10 cm. The sprayed paper was placed in a 50°C oven for drying, thereby forming a super-hydrophobic coating on the surface of the paper document.

[0044] Example 5 The difference from Example 4 is that the mass of silicon dioxide@3-aminopropyltriethoxysilane added in step (5) is 0.2 g.

[0045] Example 6 The difference from Example 4 is that the mass of silicon dioxide@3-aminopropyltriethoxysilane added in step (5) is 0.4 g.

[0046] Example 7 A method for preparing a transparent super-hydrophobic cultural relic protection material comprises the following steps: (1) Dry 2 g of 30 nm amorphous silicon dioxide in an oven at 120 °C for 12 h. (2) Add the dried amorphous silica to 100 mL of water-ethanol solution and magnetically Stir vigorously for 1 h.

[0047] (3) Add 1 mL of 3-aminopropyltriethoxysilane to a mixed solution of 18 mL of anhydrous ethanol and 2 mL of deionized water and allow to hydrolyze for 1 h. (4) The hydrolyzed 3-aminopropyltriethoxysilane solution was added dropwise to the silica solution in step (1), stirred at 65°C and 500 r / min for 4 h, and then dried in a 120°C forced air drying oven for 12 h. The obtained powder was ground and recorded as silica@3-aminopropyltriethoxysilane. (5) 0.1 g of palmitic acid and 0.1 g of silica@3-aminopropyltriethoxysilane in step (4) were added to 30 mL of anhydrous ethanol solution and stirred at 50 °C for 2 h to obtain a transparent and removable superhydrophobic material.

[0048] The super-hydrophobic material was poured into a spray gun and sprayed on the paper document from left to right three times. The distance between the spray gun and the paper was controlled at about 10 cm. The sprayed paper was placed in a 50°C oven for drying, thereby forming a super-hydrophobic coating on the surface of the paper document.

[0049] Example 8 The difference from Example 7 is that the mass of silicon dioxide@3-aminopropyltriethoxysilane added in step (5) is 0.2 g.

[0050] Example 9 The difference from Example 7 is that the mass of silicon dioxide@3-aminopropyltriethoxysilane added in step (5) is 0.4 g.

[0051] Example 10 A method for preparing a transparent super-hydrophobic cultural relic protection material comprises the following steps: (1) Dry 2.5 g of 30 nm amorphous silicon dioxide in an oven at 120 °C for 12 h. (2) Add the dried amorphous silica into 100 mL of water-ethanol solution and stir magnetically at room temperature for 1 h.

[0052] (3) Add 1 mL of 3-aminopropyltriethoxysilane to a mixed solution of 18 mL of anhydrous ethanol and 2 mL of deionized water and allow to hydrolyze for 1 h. (4) The hydrolyzed 3-aminopropyltriethoxysilane solution was added dropwise to the silica solution in step (1), stirred at 65°C and 500 r / min for 4 h, and then dried in a 120°C forced air drying oven for 12 h. The obtained powder was ground and recorded as silica@3-aminopropyltriethoxysilane. (5) 0.1 g of pearlescent fatty acid and 0.1, 0.2, and 0.4 g of silica@3-aminopropyltriethoxysilane in step (4) were added to 30 mL of anhydrous ethanol solution and stirred at 50 °C for 2 h to obtain a transparent and removable superhydrophobic material.

[0053] The super-hydrophobic material was poured into a spray gun and sprayed on the paper document from left to right three times. The distance between the spray gun and the paper was controlled at about 10 cm. The sprayed paper was placed in a 50°C oven for drying, thereby forming a super-hydrophobic coating on the surface of the paper document.

[0054] Embodiment 11 The difference from Example 10 is that the mass of silicon dioxide@3-aminopropyltriethoxysilane added in step (5) is 0.2 g.

[0055] Example 12 The difference from Example 10 is that the mass of silicon dioxide@3-aminopropyltriethoxysilane added in step (5) is 0.4 g.

[0056] Embodiment 13 A method for preparing a transparent super-hydrophobic cultural relic protection material comprises the following steps: (1) Dry 3 g of 30 nm amorphous silicon dioxide in an oven at 120 °C for 12 h. (2) Add the dried amorphous silica into 120 mL of anhydrous ethanol solution and stir magnetically at room temperature for 1 hour.

[0057] (3) Add 1 mL of 3-aminopropyltriethoxysilane to a mixed solution of 18 mL of anhydrous ethanol and 2 mL of deionized water and allow to hydrolyze for 1 h. (4) The hydrolyzed 3-aminopropyltriethoxysilane solution was added dropwise to the silica solution in step (1), stirred at 65°C and 500 r / min for 4 h, and then dried in a 120°C forced air drying oven for 12 h. The obtained powder was ground and recorded as silica@3-aminopropyltriethoxysilane. (5) 0.1 g of arachidic acid and 0.1 g of silica@3-aminopropyltriethoxysilane in step (4) were added to 30 mL of anhydrous ethanol solution and stirred at 50 °C for 2 h to obtain a transparent and removable superhydrophobic material.

[0058] The super-hydrophobic material was poured into a spray gun and sprayed on the paper document from left to right three times. The distance between the spray gun and the paper was controlled at about 10 cm. The sprayed paper was placed in a 50°C oven for drying, thereby forming a super-hydrophobic coating on the surface of the paper document.

[0059] Embodiment 14 The difference from Example 13 is that the mass of silicon dioxide@3-aminopropyltriethoxysilane added in step (5) is 0.2 g.

[0060] Embodiment 15 The difference from Example 13 is that the mass of silicon dioxide@3-aminopropyltriethoxysilane added in step (5) is 0.4 g.

[0061] The super-hydrophobic coatings prepared in Examples 1 to 5 all have good super-hydrophobicity, thermal stability and UV resistance. The super-hydrophobic coatings prepared in Examples 1 to 3 are used as examples for illustration.

[0062] Figure 2The super depth of field images of the coating obtained after spraying the materials prepared in Examples 1 to 3 of the present invention on paper documents. Among them, Figures (a1) and (a2) are super depth of field images of the original paper documents, Figures (b1) and (b2) are super depth of field images of stearic acid: SiO2@KH550=1:1 (SA:SiO2@KH550=1:1), Figures (c1) and (c2) are super depth of field images of SA:SiO2@KH550=1:2, and Figures (d1) and (d2) are super depth of field images of SA:SiO2@KH550=1:4. It can be seen from Figures (a1) and (a2) that the surface of the original paper document is smooth and flat, the fibers are clearly visible, and there are no particles. It can be seen from Figures (b1) and (b2) that a small amount of particles are deposited on the fiber surface of the modified paper document. Figures (c1) and (c2) show that there are many particles deposited on the fiber surface after modification, and the distribution is relatively uniform. Figures (d1) and (d2) show that there are a large number of particles deposited on the fiber surface after modification, and the distribution is uneven, with obvious agglomeration.

[0063] Figure 3 The SEM images of the coating obtained after spraying the materials prepared in Examples 1 to 3 of the present invention on paper documents. Among them, Figures (a1) and (a2) are SEM images of the original paper documents, Figures (b1) and (b2) are SEM images of SA:SiO2@KH550=1:1, Figures (c1) and (c2) are SEM images of SA:SiO2@KH550=1:2, and Figures (d1) and (d2) are SEM images of SA:SiO2@KH550=1:4. It can be seen from Figures (a1) and (a2) that the surface of the original paper document is smooth and flat, the fibers are clearly visible, and there are no particles. With the increase of the SiO2@KH550 particle content, the particles deposited on the fiber surface gradually increase. When SA:SiO2@KH550=1:4, the nanoparticles show obvious agglomeration on the fiber surface, which is consistent with the conclusion drawn by the ultra-depth of field microscope.

[0064] Figure 4The effect of the superhydrophobic coating on the surface of paper documents and their contact angles before and after removal is shown. Among them, (a1), (b1), and (c1) respectively show the SEM images at different magnifications before the coating is removed. It can be seen that the nanoparticles are evenly covered on the surface of the paper fibers, making the original fiber structure difficult to identify. (a2), (b2), and (c2) correspond to the SEM images after the coating is removed. At this time, the fiber structure of the paper is clearly visible, although there are still a small amount of nanoparticles remaining on the fiber surface. It is particularly noteworthy that Figure (c1) contains a contact angle illustration, indicating that in the presence of a superhydrophobic coating, the contact angle of the paper document can reach 157.1°, showing excellent superhydrophobic properties. In contrast, the contact angle illustration in Figure (c2) shows that after the coating is removed, the contact angle of the paper document drops to 67.5°, indicating that its superhydrophobic properties have significantly decreased.

[0065] Figure 5 The contact angles of paper documents under different aging conditions are shown. After 3 days of dry heat aging (temperature 105°C), wet heat aging (temperature 105°C, relative humidity 65%) and UV aging, the sprayed paper still maintains a high contact angle, indicating that its surface properties are not significantly different from those before aging. It can be concluded that the applied superhydrophobic coating not only has excellent superhydrophobic properties, but also exhibits good thermal stability and UV resistance.

[0066] Table 1 shows the color difference and visual experience of paper documents before and after modification. It can be seen from Table 1 that with the increase of SiO2 content, the color difference of paper documents before and after modification gradually increases, and the maximum △E reaches 2.12. When SA:SiO2=1:2, △E=1.41 is less than 1.5, which is difficult to distinguish with the naked eye. In line with the principle of "restoring the old as it is" for cultural relics, the mass ratio of SA and SiO2 should be controlled between 1:2.

[0067] Table 1 Color difference and visual perception of paper documents before and after modification

[0068] Figure 6 The scanned images of paper documents before and after spraying when SA:SiO2=1:2. It can be seen from the image that the appearance of the paper documents has hardly changed before and after the treatment, and the super-hydrophobic coating has not blurred or covered the handwriting, which is in line with the principle of "restoring the old as it was".

[0069] Table 1 Color difference and visual perception of paper documents before and after modification

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a transparent super-hydrophobic cultural relic protection material, characterized in that: The following steps are involved: S1: adding a silane coupling agent to a mixture of an organic solvent and water, stirring and reacting, and obtaining a hydrolyzed silane coupling agent; S2: adding the hydrolyzed silane coupling agent to the organic dispersion of silicon dioxide particles, stirring for reaction, and obtaining silicon dioxide@silane coupling agent particles; S3: adding the silicon dioxide@silane coupling agent particles into an organic solution of a chain fatty acid, wherein the carbon chain length of the chain fatty acid is 14 to 20, and stirring the reaction to obtain the transparent and removable super hydrophobic material.

2. The method for preparing a transparent super-hydrophobic cultural relics protection material according to claim 1, characterized in that: The silane coupling agent is added into a mixture of an organic solvent and water, wherein the volume ratio of the organic solvent to water and the silane coupling agent is (20-16):(4-1):(2-0.5).

3. The method for preparing a transparent super-hydrophobic cultural relics protection material according to claim 1, wherein: The ratio of the silane coupling agent to the silica particles is (2-0.5) mL: (1-3) g.

4. The method for preparing a transparent super-hydrophobic cultural relics protection material according to claim 1, wherein: In step S2, the reaction temperature of the hydrolyzed silane coupling agent and the silica particles is 25-65° C., and the reaction time is 4-8 h.

5. The method for preparing a transparent super-hydrophobic cultural relics protection material according to claim 1, characterized in that: The chain fatty acid is one of stearic acid, myristic acid, palmitic acid, pearly acid and arachidic acid.

6. The method for preparing a transparent super-hydrophobic cultural relics protection material according to claim 1, characterized in that: The ratio of the silicon dioxide@silane coupling agent particles to the chain fatty acid is (1~2):

1.

7. The method for preparing a transparent super-hydrophobic cultural relics protection material according to claim 1, wherein: The reaction temperature of adding the silicon dioxide@silane coupling agent particles to the chain fatty acid is 30-60° C. and the reaction time is 2-3 h.

8. A transparent super-hydrophobic cultural relic protection material, characterized in that: Prepared by the method according to any one of claims 1 to 7.

9. A transparent super-hydrophobic cultural relics protective coating, characterized in that: The transparent super-hydrophobic cultural relics protection material as claimed in claim 8 is coated on the surface of a substrate to obtain the material.

10. A transparent super-hydrophobic cultural relics protective coating according to claim 9, characterized in that: The water contact angle of the coating is 153° to 160°.

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