Uvioresistant aging hydrophobic lead-glazed ceramic cultural relic sealing and protecting material and preparation method thereof

Abstract

The invention relates to an anti-ultraviolet aging hydrophobic lead-glazed ceramic cultural relic sealing and protecting material and a preparation method thereof.The preparation method comprises the steps that 1, a sodium hydroxide solution is dropwise added into a zinc nitrate solution to be mixed to form white turbid liquid, and nanometer ZnO powder is obtained; 2, adding the ZnO nanospheres into a mixed system of deionized water, hexadecyl trimethyl ammonium bromide and stronger ammonia water, and performing ultrasonic dispersion to form a uniform suspension; dropwise adding ethyl silicate for mechanical stirring, centrifuging the obtained product, alternately washing with deionized water and ethanol, drying, and calcining to obtain nano ZnO coated SiO2; and 3, preparing a Paraloid B72 base solution, sequentially adding an FEVE emulsion, a KH-570 silane coupling agent and ZnO coated SiO2, carrying out ultrasonic treatment to form a homogeneous dispersion liquid, forming a film on the surface of a lead-glazed ceramic matrix, and curing at room temperature to obtain the composite sealing and protecting coating with ultraviolet aging resistance and hydrophobic functions. According to the invention, permeation of moisture in the air can be effectively blocked, further erosion of the moisture to the lead-glazed ceramic cultural relics is prevented, and a more reliable long-term protection guarantee is provided for the cultural relics.

Description

Technical Field

[0001] The present invention belongs to the technical field of cultural relic conservation materials, and particularly relates to a lead-glazed pottery cultural relic conservation material with anti-ultraviolet aging and hydrophobic properties and a preparation method thereof. Background Art

[0002] Due to its unique aesthetic value and relatively low production cost, lead-glazed pottery has become a favored funerary object. However, lead-glazed pottery cultural relics are susceptible to environmental factors during long-term burial, and "silver glaze" diseases are likely to appear on the surface. This disease not only causes apparent deterioration such as glaze fading and embrittlement, but also leads to serious damage to the structure of the artifact itself. Research shows that the formation of the "silver glaze" disease is due to the formation of an acidic aqueous solution by H2O and CO2 in the environment under specific conditions. The H + in the solution undergoes an ion exchange reaction with Pb 2+ on the glaze surface, resulting in the precipitation of a large amount of Pb 2+ These free Pb 2+ further combines with CO3 2- to form insoluble PbCO3. When the PbCO3 in the solution reaches the saturation concentration, it will crystallize and deposit on the glaze surface, forming a loose and porous silver glaze layer. Water can still enter the voids and continue to corrode. Over time, the disease will continue to intensify. To prevent the "silver glaze" disease of lead-glazed pottery cultural relics from deepening further in the natural environment, coating a hydrophobic conservation material on the surface of lead-glazed pottery cultural relics is an effective means to solve this problem.

[0003] Currently, Paraloid B72 is a commonly used conservation material for cultural relics, but its anti-ultraviolet aging performance is poor. After long-term use, the surface of the material is prone to yellowing, embrittlement, and even cracking problems, and it cannot meet the hydrophobic conservation work of lead-glazed pottery cultural relics.

[0004] Therefore, constructing a lead-glazed pottery coating with anti-ultraviolet aging and hydrophobic properties is of great significance for extending the lifespan of lead-glazed pottery cultural relics. Summary of the Invention

[0005] In order to overcome the above problems existing in the prior art, the purpose of the present invention is to provide a lead-glazed pottery cultural relic conservation material with anti-ultraviolet aging and hydrophobic properties and a preparation method thereof, which can effectively block the penetration of moisture in the air, prevent further erosion of lead-glazed pottery cultural relics by moisture, and provide more reliable long-term protection for cultural relics.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0007] An anti-ultraviolet aging and hydrophobic sealing material for lead-glazed pottery cultural relics, which is a ZnO@SiO2-B72 / FEVE composite coating. A dense and uniformly distributed sub-micron pore structure is formed on the surface of the composite coating, and its average pore diameter is about 500 nm; each characteristic element in the composite coating shows a continuous and uniform distribution state in the observation area.

[0008] A preparation method of an anti-ultraviolet aging and hydrophobic sealing material for lead-glazed pottery cultural relics, comprising the following steps;

[0009] Step 1: Dropwise add sodium hydroxide solution into zinc nitrate solution, mix to form a white suspension, and obtain nano-ZnO powder after washing and calcination;

[0010] Step 2: Add ZnO nano-spheres into a mixed system composed of deionized water, cetyltrimethylammonium bromide (CTAB) and concentrated ammonia water, and ultrasonically disperse to form a uniform suspension; dropwise add tetraethyl orthosilicate and mechanically stir. After centrifuging the obtained product, wash it alternately with deionized water and ethanol, and then dry and calcine to obtain nano-ZnO@SiO2;

[0011] Step 3: Prepare a Paraloid B72 base solution, sequentially add FEVE emulsion, KH-570 silane coupling agent and ZnO@SiO2, ultrasonically treat to form a homogeneous dispersion, and use spraying method or dipping method to form a film on the surface of the lead-glazed pottery matrix, and cure at room temperature to obtain a composite sealing coating with both anti-ultraviolet aging and hydrophobic functions.

[0012] In the said Step 1, the molar ratio of zinc nitrate to sodium hydroxide is 1:2; the concentration ratio of zinc nitrate solution to sodium hydroxide solution is 1:2.

[0013] The said Step 1 is specifically that, under the condition of continuous stirring, dropwise add 1M NaOH solution into 0.5M zinc nitrate solution to form a white suspension;

[0014] After the mixed solution is stirred for a long time (more than 8 h), wash it alternately with deionized water and ethanol three times, wait until it is fully dried, and then calcine it in a muffle furnace at 400 °C for 2-3 h to obtain nano-ZnO powder.

[0015] In the said Step 2, the mass ratio of deionized water:CTAB:concentrated ammonia water is = 100:3:20.

[0016] In the said Step 2, the mass ratio of ZnO nano-spheres:CTAB:tetraethyl orthosilicate (TEOS) is 1:3:2.

[0017] Step 2 is specifically as follows: Coating the SiO2 layer by the sol-gel method: adding 0.2 g of the prepared ZnO nanospheres into a mixed system containing 20 mL of deionized water, 0.6 g of cetyltrimethylammonium bromide (CTAB), and 4.0 mL of concentrated ammonia water, and ultrasonically dispersing for 30 min to form a uniform suspension;

[0018] Dropwise add 0.4 g of tetraethyl orthosilicate (TEOS), react for more than 12 h under continuous stirring, after centrifuging the obtained product, wash it alternately with deionized water and ethanol, wait until it is fully dried, and calcine it at 600 °C for 5 - 6 h to obtain nano-ZnO@SiO2.

[0019] In Step 3, the mass ratio of Paraloid B72: FEVE: silane coupling agent: ZnO@SiO2 is 75:21:3:1.

[0020] Step 3 is specifically as follows: Prepare a 10 wt% base solution of Paraloid B72 (75 g), sequentially add 21 g of 10 wt% FEVE emulsion, 3 g of KH-570 silane coupling agent, and 1 g of ZnO@SiO2 nano-filler, ultrasonically treat to form a homogeneous dispersion, and use the spraying method or dipping method to form a film on the surface of the lead-glazed pottery substrate, and cure at room temperature for more than 12 h to obtain a composite sealing and protecting coating with both anti-ultraviolet aging and hydrophobic functions.

[0021] The pressure of the spraying method is 0.5 - 1 MPa, the spraying distance is 20 - 30 cm, and the single spraying amount is 1 - 3 g / dm 2 ;

[0022] The dipping method is a pulling rate of 5 - 10 s.

[0023] The beneficial effects of the present invention:

[0024] The ZnO@SiO2-B72 / FEVE composite coating has high transparency, does not affect the color of the cultural relic itself, and has excellent anti-ultraviolet and super-hydrophobic properties. After film formation, the composite coating can not only effectively prevent the pollution of moisture and harmful particles in the air, but also resist the aging of the sealing and protecting material by ultraviolet rays, extend the service life of the sealing and protecting material, thereby reducing the influence and damage of the external natural environment on lead-glazed pottery cultural relics, and more effectively laying a foundation for the long-term preservation of lead-glazed pottery cultural relics.

[0025] ZnO nanoparticles with wide bandgap characteristics are selected as the ultraviolet shielding component, and the ZnO@SiO2 core-shell structure is prepared by the sol-gel method: the SiO2 shell layer not only retains the ultraviolet absorption ability of ZnO (200 - 380 nm), but also inhibits the oxidative attack of photogenerated holes on the organic resin through physical isolation. Fluorocarbon resin FEVE is used as the functional component. The high bond energy C—F bond in the FEVE molecule endows the material with an extremely low surface energy (the static contact angle can reach more than 120°), and this superhydrophobic property can effectively block the penetration of environmental moisture, thus cutting off the key path for the development of silver glaze diseases.

[0026] In addition, the preparation method of the present invention has the characteristics of simple operation and short production cycle, and the raw materials are easy to obtain and the process is controllable, having the potential for large-scale industrial production. This characteristic can not only meet the urgent needs of the cultural relic protection field for high-efficiency protective materials, but also provide a practical solution for the scientific protection of lead-glazed pottery cultural relics, having important application value and promotion significance. Brief Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the preparation process of the ZnO@SiO2-B72 / FEVE composite coating.

[0028] Figure 2 It is a schematic diagram of the ultraviolet absorption spectra before and after B72 modification.

[0029] Figure 3 (a) is a schematic diagram of the contact angle of B72; Figure 3 (b) is a schematic diagram of the contact angle of ZnO@SiO2-B72 / FEVE.

[0030] Figure 4 It is the morphological characteristics and element distribution of the ZnO@SiO2-B72 / FEVE composite coating: (a) the surface morphology of the composite coating, (b) the high-magnification SEM image of the composite coating, (c) the enlarged SEM image of the yellow area in Figure (b), and (d - h) the EDS maps of C, O, F, Zn, and Si elements.

[0031] Figure 5 It is a schematic diagram of the morphological changes of the sample before and after applying the ZnO@SiO2-B72 / FEVE composite coating. Detailed Description of the Invention

[0032] The present invention will be further described in detail below with reference to the drawings.

[0033] Example 1:

[0034] (1) Preparation of nano-ZnO: Zinc nitrate and sodium hydroxide were respectively dissolved in 100 mL of distilled water. The sodium hydroxide solution was added dropwise to the zinc nitrate solution, and then the alkaline solution was stirred for 8 h. The product was washed with distilled water and ethanol (1:1). Then, the moisture was dried at 70 °C, and finally, it was further calcined at 400 °C for 2 h.

[0035] (2) Preparation of nano-ZnO@SiO2: Sol-gel method was used to coat silica on the surface of zinc oxide to prepare nanospheres. The synthesized ZnO (0.1 g) was added to a conical flask containing water (10 ml), CTAB (0.3 g), and concentrated ammonia solution (0.5 g, 2.0 mL), and was fully dispersed. After dispersion, tetraethyl orthosilicate (0.2 g) was added dropwise, and the reaction was carried out under continuous mechanical stirring for 12 h. The product was washed with distilled water and ethanol (1:1), and calcined at 600 °C for 5 h.

[0036] (3) Preparation of ZnO@SiO2-B72 / FEVE composite coating: Prepare a 10 wt% acetone solution of Paraloid B72, and then disperse 10 wt% of FEVE, 3 wt% of silane coupling agent, and 1 wt% of ZnO@SiO2 into the Paraloid B72 solution and ultrasonically treat it. The uniformly dispersed dispersion was sprayed onto the surface of lead-glazed pottery cultural relics, with a spraying amount of 1 g, a spraying pressure of 0.5 MPa, a nozzle diameter of 0.5 mm, and a distance between the spray gun and the lead-glazed pottery cultural relics of 20 cm.

[0037] Example 2:

[0038] (1) Preparation of nano-ZnO: Zinc nitrate and sodium hydroxide were respectively dissolved in 100 mL of distilled water. The sodium hydroxide solution was added dropwise to the zinc nitrate solution, and then the alkaline solution was stirred for 8 h. The product was washed with distilled water and ethanol (1:1). Then, the moisture was dried at 70 °C, and finally, it was further calcined at 400 °C for 3 h.

[0039] (2) Preparation of nano-ZnO@SiO2: Sol-gel method was used to coat silica on the surface of zinc oxide to prepare nanospheres. The synthesized ZnO (0.1 g) was added to a conical flask containing water (10 ml), CTAB (0.3 g), and concentrated ammonia solution (0.5 g, 2.0 mL), and was fully dispersed. After dispersion, tetraethyl orthosilicate (0.2 g) was added dropwise, and the reaction was carried out under continuous mechanical stirring for 12 h. The product was washed with distilled water and ethanol (1:1), and calcined at 600 °C for 6 h.

[0040] (3) Preparation of ZnO@SiO2-B72 / FEVE composite coating: Prepare 10wt% Paraloid B72 acetone solution, then add 10wt% FEVE, 3wt% silane coupling agent, and 1wt% ZnO@SiO2 to the Paraloid B72 solution and disperse it, and then ultrasonically treat it. Spray the evenly dispersed dispersion onto the surface of the lead-glazed pottery artifact, with a spraying amount of 1g, a spraying pressure of 0.5MPa, a spray gun nozzle diameter of 0.5mm, and a distance of 20cm between the spray gun and the lead-glazed pottery artifact.

[0041] Embodiment 3:

[0042] (1) Preparation of nano ZnO: Dissolve zinc nitrate and sodium hydroxide in 100 mL of distilled water, add the sodium hydroxide solution dropwise into the zinc nitrate solution, stir the alkaline solution for 8 h, wash the product with distilled water and ethanol (1:1), dry the water at 70 °C, and calcine at 400 °C for 2.5 h.

[0043] (2) Preparation of nano ZnO@SiO2: Nanospheres were prepared by coating the surface of zinc oxide with silicon dioxide using the sol-gel method. The synthesized ZnO (0.1 g) was added to a conical flask containing water (10 ml), CTAB (0.3 g) and concentrated ammonia solution (0.5 g, 2.0 mL) and fully dispersed. After dispersion, ethyl orthosilicate (0.2 g) was added dropwise and reacted for 12 h under continuous mechanical stirring. The product was washed with distilled water and ethanol (1:1) and calcined at 600 °C for 5.5 h.

[0044] (3) Preparation of ZnO@SiO2-B72 / FEVE composite coating: Prepare 10wt% Paraloid B72 acetone solution, then add 10wt% FEVE, 3wt% silane coupling agent, and 1wt% ZnO@SiO2 to the Paraloid B72 solution and disperse it, and then ultrasonically treat it. Spray the evenly dispersed dispersion onto the surface of the lead-glazed pottery artifact, with a spraying amount of 1g, a spraying pressure of 0.5MPa, a spray gun nozzle diameter of 0.5mm, and a distance of 20cm between the spray gun and the lead-glazed pottery artifact.

[0045] like Figure 1 As shown; or immerse the lead-glazed pottery artifacts into the above solution, and then immerse the pottery simulation sample into the above solution for coating, take it out after 5s, and dry it in a room temperature environment.

[0046] The anti-ultraviolet aging hydrophobic lead-glazed pottery cultural relic sealing coating can be obtained.

[0047] like Figure 5As shown, the morphological changes before and after of the sample coated with ZnO@SiO2-B72 / FEVE composite coating can be clearly observed: The sample coated with ZnO@SiO2-B72 / FEVE composite coating maintained its original morphological and color characteristics before and after treatment, without any adverse effects on its macroscopic morphology. This is in line with the basic principle of "not changing the appearance of cultural relics" in the law of cultural relics protection.

[0048] Figure 2 The test results of the ultraviolet-visible absorption spectrum are shown. Compared with the unmodified B72 coating, the ZnO@SiO2-B72 / FEVE composite coating exhibits significantly enhanced ultraviolet absorption characteristics in the wavelength range of 200-300 nm, and obvious absorption peaks are formed in this region. This phenomenon indicates that the introduction of ZnO@SiO2 nanoparticles significantly improves the ultraviolet absorption ability of the coating. It is worth noting that after the wavelength exceeds 300 nm, although the absorbance of the composite coating decreases, its value is still significantly higher than that of the pure B72 coating. This phenomenon can be attributed to the scattering effect of ZnO@SiO2 nanoparticles in the visible light region.

[0049] Figure 3 The test results of the contact angle of B72 resin before and after modification are shown. The contact angle before modification was 79°, while it significantly increased to 120° after modification, indicating that its hydrophobic performance has increased by 51.9%. This significant improvement is mainly attributed to the synergistic effect of the hydrophobic characteristics of nanoparticles and the low surface energy FEVE material. Nanoparticles enhance the hydrophobic performance of the material by forming a microscopic rough structure on its surface; while the low surface energy characteristics of the FEVE material further reduce the spreading ability of the liquid on the material surface. This modification not only significantly improves the hydrophobic performance of the material, but also provides a more reliable guarantee for its application in the field of cultural relics protection and other fields.

[0050] Figure 4 The scanning electron microscope (SEM) morphological characteristics and elemental distribution analysis results of the ZnO@SiO2-B72 / FEVE composite coating are shown. Through SEM observation, it can be found that a dense and uniformly distributed submicron-sized pore structure is formed on the surface of the modified composite coating, and its average pore diameter is about 500 nm. According to the Cassie-Baxter wetting theory, the synergistic effect of this regularly distributed microscopic rough structure and the low surface energy fluorinated resin in the system forms a stable air cushion layer at the solid-liquid interface. This not only significantly reduces the actual contact area of water droplets, but also increases the apparent contact angle, thus endowing the coating with superhydrophobic characteristics.

[0051] Further SEM observation shows that ZnO@SiO2 nanoparticles are uniformly distributed in the resin matrix in a discrete state (such as Figure 4as shown in c). Through energy-dispersive X-ray spectroscopy (EDS) surface scanning analysis ( Figure 4 from d to h), it can be seen that the C and O elements mainly come from the B72 and FEVE resin matrices, the F element originates from the fluorocarbon chain segments in the FEVE resin, while the Zn and Si elements correspond to the ZnO@SiO2 nanoparticles. Each characteristic element shows a continuous and uniform distribution state in the observation area, indicating that there is good compatibility between the nanoparticles and the resin matrix, and no obvious phase separation phenomenon occurs. This uniform microstructure feature confirms the effective composite of multi-component materials during the preparation of the composite coating.

[0052] The present invention uses the sol-gel method to prepare ZnO@SiO2 core-shell structured nanoparticles. Through the physical isolation of the SiO2 shell layer, the oxidative damage of the photocatalytic activity of ZnO to the organic resin matrix is effectively inhibited, while the ultraviolet absorption ability (200 - 380 nm) of ZnO is retained. This core-shell structure design not only solves the problem of material degradation caused by excessive photocatalytic activity of traditional inorganic nanomaterials, but also significantly improves the anti-ultraviolet performance of the coating. By combining ZnO@SiO2 nanoparticles with the fluorocarbon resin FEVE, a ZnO@SiO2-B72 / FEVE composite coating with anti-ultraviolet, superhydrophobic and good optical properties is constructed. This multi-component composite system makes full use of the advantages of each component: ZnO@SiO2 provides ultraviolet shielding function, FEVE endows the coating with superhydrophobic characteristics, and Paraloid B72, as the matrix material, provides good permeability and mechanical properties. This design significantly improves the comprehensive protection efficiency of the coating.

Claims

1. A UV-resistant, aging-resistant, hydrophobic lead-glazed pottery cultural relic sealing material, characterized in that: It is a ZnO@SiO2-B72 / FEVE composite coating. A dense and evenly distributed submicron pore structure is formed on the surface of the composite coating, and the average pore size is about 500nm. The characteristic elements in the composite coating show a continuous and uniform distribution state in the observation area.

2. A method for preparing a UV-resistant, hydrophobic lead-glazed pottery cultural relic sealing material, characterized in that: The steps include: Step 1: Add sodium hydroxide solution dropwise into zinc nitrate solution, mix to form a white suspension, and wash and calcine to obtain nano ZnO powder; Step 2: Add ZnO nanospheres to a mixed system consisting of deionized water, hexadecyltrimethylammonium bromide (CTAB) and concentrated ammonia water, and disperse by ultrasonication to form a uniform suspension; add ethyl silicate dropwise for mechanical stirring, centrifuge the obtained product, wash it alternately with deionized water and ethanol, dry it, and calcine it to obtain nano ZnO@SiO2; Step 3: Prepare Paraloid B72 base liquid, add FEVE emulsion, KH-570 silane coupling agent and ZnO@SiO2 in sequence, perform ultrasonic treatment to form a homogeneous dispersion, form a film on the surface of the lead-glazed ceramic substrate by spraying or dipping, and cure at room temperature to obtain a composite protective coating with both UV resistance and hydrophobicity.

3. The method for preparing a UV-resistant, aging-resistant, hydrophobic lead-glazed pottery cultural relic sealing material according to claim 2, characterized in that: In the step 1, the molar ratio of zinc nitrate to sodium hydroxide is 1:2; the concentration ratio of zinc nitrate solution to sodium hydroxide solution is 1:

2.

4. The method for preparing a UV-resistant, aging-resistant, hydrophobic lead-glazed pottery cultural relic sealing material according to claim 2, characterized in that: Specifically, step 1 comprises adding 1M NaOH solution dropwise into 0.5M zinc nitrate solution under continuous stirring to form a white suspension; After being stirred for a long time, the mixed solution was washed alternately with deionized water and ethanol for three times, and then fully dried, and then calcined in a muffle furnace at 400° C. for 2-3 hours to obtain nano ZnO powder.

5. The method for preparing a UV-resistant, aging-resistant, hydrophobic lead-glazed pottery cultural relic sealing material according to claim 2, characterized in that: In the step 2, the mass ratio of deionized water: CTAB: concentrated ammonia water is 100:3:

20.

6. The method for preparing a UV-resistant, aging-resistant, hydrophobic lead-glazed pottery cultural relic sealing material according to claim 2, characterized in that: In the step 2, the mass ratio of ZnO nanospheres: CTAB: tetraethyl orthosilicate (TEOS) is 1:3:

2.

7. The method for preparing a UV-resistant, aging-resistant, hydrophobic lead-glazed pottery cultural relic sealing material according to claim 2, characterized in that: The step 2 is specifically as follows: adding 0.2 g of the prepared ZnO nanospheres into a mixture containing 20 mL of deionized water, 0.6 g of hexadecyltrimethylammonium bromide (CTAB) and 4.0 mL of concentrated ammonia water, and performing ultrasonic dispersion for 30 minutes to form a uniform suspension; 0.4 g of tetraethyl orthosilicate (TEOS) was added dropwise, and the mixture was reacted for more than 12 h under continuous stirring. The obtained product was centrifuged, washed alternately with deionized water and ethanol, dried sufficiently, and calcined at 600 °C for 5-6 h to obtain nano ZnO@SiO2.

8. The method for preparing a UV-resistant, aging-resistant, hydrophobic lead-glazed pottery cultural relic sealing material according to claim 2, characterized in that: In the step 3, the mass ratio of Paraloid B72:FEVE:silane coupling agent:ZnO@SiO2 is 75:21:3:

1.

9. The method for preparing a UV-resistant, aging-resistant, hydrophobic lead-glazed pottery cultural relic sealing material according to claim 2, characterized in that: The step 3 is specifically as follows: preparing 75g of 10wt% Paraloid B72 base liquid, adding 21g of 10wt% FEVE emulsion, 3g of KH-570 silane coupling agent and 1g of ZnO@SiO2 nanofiller in sequence, ultrasonically treating to form a homogeneous dispersion, forming a film on the surface of the lead-glazed ceramic substrate by spraying or dipping, and curing at room temperature for more than 12h to obtain a composite protective coating with both UV resistance and hydrophobicity.

10. The method for preparing a UV-resistant, aging-resistant, hydrophobic lead-glazed pottery cultural relic sealing material according to claim 9, characterized in that: The spraying pressure is 0.5-1MPa, the spraying distance is 20-30cm, and the single spraying amount is 1-3g / dm 2 ; The dipping method has a pulling rate of 5-10s.

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