Bionic patterned biomass-based photoluminescence polyurethane coating for leather and preparation method of bionic patterned biomass-based photoluminescence polyurethane coating

Abstract

The invention discloses a preparation method of a bionic patterned biomass-based photoluminescence polyurethane coating for leather. The preparation method specifically comprises the following steps: step 1, preparing a zirconium hydrogen phosphate crosslinking body dispersion liquid; step 2, preparing a bionic patterned biomass-based photoluminescence polyurethane emulsion for leather according to a product obtained in the step 1; and step 3, preparing the bionic patterned biomass-based photoluminescence polyurethane coating for leather according to the product obtained in the step 2. The invention further discloses a bionic patterned biomass-based photoluminescence polyurethane coating for leather, and the prepared polyurethane coating has a better pattern display function and can be applied to leather finishing and anti-counterfeiting.

Description

Technical Field

[0001] The invention belongs to the technical field of leather coatings, relates to a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather, and also relates to a preparation method of the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather. Background Art

[0002] Polyurethane (PU) is a class of high-molecular-weight polymers containing carbamate groups, synthesized from polyisocyanates, polyols, and small-molecule diols or diamines. Its molecular chain structure contains both hard segments (carbamate segments) and soft segments (polyol segments). In the leather industry, PU is often used as a primary component of high-performance coatings due to its simple preparation process, wide availability, high solids content, high mechanical strength, and excellent film-forming properties. However, due to the inherent environmental and human health risks inherent in traditional solvent-based PU, water-based PU has recently become a green alternative to traditional solvent-based PU coatings due to its environmental safety, low viscosity, and excellent chemical resistance, flexibility, and mechanical properties.

[0003] In recent years, the global consumer market has seen a surge in demand for diversified and personalized leather products with features such as flame retardancy, antibacterial properties, luminescence, water resistance, antifouling, self-cleaning, and electromagnetic / UV shielding. However, existing polyurethane (PU) leather coatings are unable to meet these high-performance technical requirements. Currently, most photoluminescent PU leather coatings use carbon quantum dots as the functional motifs. However, these can pose safety risks, suffer from poor controllability in preparation, and exhibit poor compatibility with the PU matrix. Therefore, the development of new preparation systems for patterned biomass-based polyurethane coatings for high-performance leather applications is urgently needed. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather. The polyurethane coating prepared by this method has good pattern display function and can be used for leather finishing and anti-counterfeiting applications.

[0005] Another object of the present invention is to provide a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather.

[0006] The first technical solution adopted by the present invention is a method for preparing a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather, which specifically comprises the following steps: Step 1, preparing a zirconium hydrogen phosphate cross-linked dispersion; Step 2, preparing a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather according to the product obtained in step 1; Step 3: preparing a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather according to the product obtained in step 2.

[0007] The first technical solution of the present invention is also characterized in that: The specific process of step 1 is: Step 1.1, adding the stripping agent solution dropwise to the zirconium hydrogen phosphate dispersion and stirring uniformly with a magnetic stirrer at room temperature; Step 1.2, adding concentrated phosphoric acid dropwise to the zirconium hydrogen phosphate dispersion treated in step 1.1 to adjust the pH to acidic; Step 1.3, adding the organic crosslinking agent solution dropwise to the zirconium hydrogen phosphate dispersion treated in step 1.2, stirring evenly at room temperature, and finally dialyzing with deionized water to remove unreacted crosslinking agent molecules to obtain a zirconium hydrogen phosphate crosslinked dispersion.

[0008] In step 1.1, the molar ratio of zirconium hydrogen phosphate to the stripping agent is 1:(6-8), and the stripping agent is any one of tetrabutylammonium hydroxide, propylamine, and allylamine.

[0009] In step 1.2, concentrated phosphoric acid is used to adjust the pH of the solution to a range of 1.5 to 2.5.

[0010] In step 1.3, the molar ratio of the organic cross-linking agent to zirconium hydrogen phosphate is 1:(150-200), and the organic cross-linking agent is any one of tannic acid, gallic acid, caffeic acid or dopamine.

[0011] The specific process of step 2 is: The polyurethane solution, the fluorescent agent and the zirconium hydrogen phosphate cross-linked dispersion prepared in step 1 are mixed, and magnetic stirring is performed at room temperature to obtain a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather.

[0012] In step 2, the mass ratio of the polyurethane solution to the zirconium hydrogen phosphate cross-linked dispersion and the fluorescent agent is 1:0.01-0.05:0.00005-0.00015.

[0013] In step 2, the polyurethane is any one of castor oil-based polyurethane, sorbitol-based polyurethane or lignin-based polyurethane, and the solid content of the polyurethane in the polyurethane solution is 20%; the fluorescent agent is any one of rhodamine 6G, rhodamine B or fluorescein.

[0014] The specific process of step 3 is: take the product obtained in step 2 and put it into the spray gun, spray it on the leather surface that fits the hollow pattern, and finally place the sprayed leather in an oven. After the moisture is completely evaporated, the bionic patterned coating for leather is obtained.

[0015] The second technical solution adopted by the present invention is that the bionic patterned biomass-based photoluminescent polyurethane coating for leather is prepared by adopting the preparation method of the bionic patterned biomass-based photoluminescent polyurethane coating for leather.

[0016] The beneficial effects of the present invention are as follows: 1. The present invention introduces two-dimensional nanosheet materials into a polyurethane coating, which can form a coating with a natural skin wrinkle bionic structure on the leather surface, thereby enhancing the mechanical properties of the coating.

[0017] 2. Perform fluorescent pattern design on the leather surface to enable the leather coating to have information display and anti-counterfeiting properties.

[0018] 3. The material of the present invention has a wide range of sources, low price, green and environmental protection, and the method is simple, effective, and highly functional. It is expected to be widely used in the leather coating market. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The natural skin wrinkle structure of the polyurethane composite film formed by the biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather prepared by Example 2 of the method for preparing the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather of the present invention is similar to that of the natural skin wrinkle structure; FIG2 (a) is a stress-strain curve of a polyurethane composite film formed from a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather prepared by Example 2 of the method for preparing a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather of the present invention; FIG2( b ) shows the toughness and Young's modulus of a polyurethane composite film formed from a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather prepared by Example 2 of the method for preparing a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather of the present invention; FIG2 (c) shows the change in fluorescence color due to different deformations of a polyurethane composite film formed from a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather prepared by Example 2 of the method for preparing a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather of the present invention; FIG3 (a) is a photograph of the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather prepared in Example 3 taken under sunlight; FIG3( b ) is a photograph of the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather prepared in Example 3 under ultraviolet light; FIG4 (a) is a photograph of the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather prepared in Example 4 taken under sunlight; FIG4( b ) is a photograph of the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather prepared in Example 4 under ultraviolet light. DETAILED DESCRIPTION

[0020] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] The method for preparing a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather of the present invention specifically comprises the following steps: Step 1, preparing a zirconium hydrogen phosphate crosslinked dispersion, the specific process is: A 0.1 mol / L stripper solution was added dropwise to 100 mL of a 0.05 mol / L zirconium hydrogen phosphate dispersion and magnetically stirred at room temperature for 6 h. 14.63 mol / L concentrated phosphoric acid was then added dropwise to the dispersion to adjust the pH. Subsequently, a 1 mg / mL organic crosslinker solution was added dropwise to the pH-adjusted dispersion and stirred at room temperature for 4 to 8 h. Finally, the solution was dialyzed with deionized water for 24 h to remove unreacted crosslinker molecules, ultimately obtaining an 8 mg / mL zirconium hydrogen phosphate crosslinked dispersion.

[0022] The stripping agent is any one of tetrabutylammonium hydroxide, propylamine, and allylamine; The molar ratio of zirconium hydrogen phosphate to stripping agent is 1:(6~8); Use concentrated phosphoric acid to adjust the solution pH range to 1.5~2.5; The organic cross-linking agent is any one of tannic acid, gallic acid, caffeic acid or dopamine; The molar ratio of the organic cross-linking agent to the zirconium hydrogen phosphate is 1:(150~200).

[0023] Step 2, preparing a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather, the specific process is as follows: The polyurethane solution was mixed with a fluorescent agent and a zirconium hydrogen phosphate cross-linked body dispersion, and magnetic stirring was performed at room temperature for 2 hours to obtain a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather.

[0024] The polyurethane used is any one of castor oil-based polyurethane, sorbitol-based polyurethane or lignin-based polyurethane, and the solid content of the polyurethane in the polyurethane solution is 20%; The fluorescent agent is any one of rhodamine 6G, rhodamine B or fluorescein; The mass ratio of the polyurethane solution, the zirconium hydrogen phosphate cross-linked dispersion, and the fluorescent agent is 1:0.01~0.05:0.00005~0.00015.

[0025] Step 3, preparing a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather, the specific process is as follows: Take the paint from step 2 and put it into the spray gun, spray it on the leather surface that fits the hollow pattern, and finally place the sprayed leather in a 50°C oven. After the water is completely evaporated, the bionic patterned coating for leather is obtained.

[0026] Leather type is either chrome tanned or vegetable tanned.

[0027] The spraying method is to spray with a spray gun three times, with a spraying volume of 50mL / m 2 .

[0028] The present invention ultimately obtains a biomimetic patterned biomass-based photoluminescent polyurethane leather coating, which has a bionic structure of natural skin wrinkles and can enhance the mechanical properties of the coating.

[0029] By spraying a pattern template on the leather surface, a fluorescent coating can be formed on the leather surface, realizing information display and anti-counterfeiting performance application of the leather coating.

[0030] Example 1 1.6 g of zirconium hydrogen phosphate was weighed and added to 100 mL of deionized water to obtain a 0.05 mol / L zirconium hydrogen phosphate dispersion; 5.68 g of tetrabutylammonium hydroxide was weighed and dissolved in 100 mL of deionized water to obtain a 0.32 mol / L tetrabutylammonium hydroxide solution, and then the tetrabutylammonium hydroxide solution was slowly added dropwise to the zirconium hydrogen phosphate dispersion. Concentrated phosphoric acid was added dropwise to the above dispersion to adjust the pH to 1.5, and magnetically stirred at room temperature for 6 hours. Then, 50 mL of 1 mg / mL tannic acid solution was prepared and added to the zirconium hydrogen phosphate solution. It was stirred at room temperature for 4 hours, and then the above solution was dialyzed with distilled water for 24 hours using a 1000 Da dialysis bag to remove unreacted tannic acid, finally obtaining an 8 mg / mL zirconium hydrogen phosphate cross-linked dispersion. Next, 10 mL of castor oil aqueous polyurethane emulsion with a solid content of 20% and 2 mL of 0.1 mg / mL rhodamine B solution were taken, mixed with 2.5 mL of zirconium hydrogen phosphate cross-linked dispersion and stirred at room temperature for 2 hours to obtain a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather. Finally, the polyurethane emulsion was loaded into a spray gun and evenly sprayed on the vegetable tanned leather once. It was placed in a 50°C oven for drying and repeated three times to obtain a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather.

[0031] Example 2 1.6 g of zirconium hydrogen phosphate was weighed and added to 100 mL of deionized water to obtain a 0.05 mol / L zirconium hydrogen phosphate dispersion; 5.68 g of tetrabutylammonium hydroxide was weighed and dissolved in 100 mL of deionized water to obtain a 0.32 mol / L tetrabutylammonium hydroxide solution, which was then slowly added dropwise to the zirconium hydrogen phosphate dispersion. Concentrated phosphoric acid was added dropwise to the above dispersion to adjust the pH to 2.5, and magnetically stirred at room temperature for 6 hours. Subsequently, 50 mL of 1 mg / mL tannic acid solution was prepared and added to the zirconium hydrogen phosphate solution, stirred at room temperature for 8 hours, and then the above solution was dialyzed with distilled water for 24 hours using a 1000 Da dialysis bag to remove unreacted tannic acid, finally obtaining an 8 mg / mL zirconium hydrogen phosphate cross-linked dispersion. Next, 10 mL of castor oil-based water-based polyurethane with a solid content of 20% and 2 mL of 0.1 mg / mL rhodamine B solution were taken, mixed with 2.5 mL of zirconium hydrogen phosphate cross-linked dispersion and stirred at room temperature for 2 hours to obtain a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather. Finally, the polyurethane emulsion was loaded into a spray gun and evenly sprayed once on vegetable tanned leather. It was placed in a 50°C oven for drying and repeated three times to obtain a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather.

[0032] Since the biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather is mainly applied to the leather surface to form a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather, in order to characterize and test the structure and performance of the obtained coating, the polyurethane emulsion is usually evenly poured onto a polytetrafluoroethylene plate and placed in an oven to obtain a polyurethane composite film. By characterizing the structure and properties of the film, its application performance when used as a leather coating is compared, as follows: In order to verify the mechanical properties of the biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather prepared in Example 2, 20 mL of the biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather prepared in Example 2 was evenly poured onto a polytetrafluoroethylene plate and placed in an oven at 50°C for 16 hours to form a film, thereby obtaining a photosensitive dual-responsive polyurethane composite film with excellent mechanical properties, which can exhibit fluorescent color changes affected by elongation under irradiation of 365 nm ultraviolet light.

[0033] Example 3 1.6 g of zirconium hydrogen phosphate was weighed and added to 100 mL of deionized water to obtain a 0.05 mol / L zirconium hydrogen phosphate dispersion; 1.77 g of propylamine was weighed and dissolved in 100 mL of deionized water to obtain a 0.3 mol / L propylamine solution, which was then slowly added dropwise to the zirconium hydrogen phosphate dispersion. Concentrated phosphoric acid was added dropwise to the above dispersion to adjust the pH to 2, and magnetically stirred at room temperature for 6 hours. Subsequently, 50 mL of 2 mg / mL gallic acid solution was prepared and added to the zirconium hydrogen phosphate solution, stirred at room temperature for 6 hours, and then the above solution was dialyzed with distilled water for 24 hours using a 500 Da dialysis bag to remove unreacted gallic acid, finally obtaining an 8 mg / mL zirconium hydrogen phosphate cross-linked dispersion. Next, 10 mL of sorbitol aqueous polyurethane with a solid content of 20% and 1 mL of 0.1 mg / mL fluorescein solution were taken, mixed with 5 mL of zirconium hydrogen phosphate cross-linked dispersion and stirred at room temperature for 2 hours to obtain a bionic patterned biomass-based photoluminescent polyurethane emulsion for leather. Finally, it was loaded into a spray gun and evenly sprayed once on vegetable tanned leather with a hollow butterfly pattern. It was placed in a 50°C oven for drying and repeated 3 times to obtain a bionic patterned biomass-based photoluminescent polyurethane coating for leather, which can display a clear light yellow butterfly pattern under 365nm ultraviolet light.

[0034] Example 4 1.6 g of zirconium hydrogen phosphate was weighed and added to 100 mL of deionized water to obtain a 0.05 mol / L zirconium hydrogen phosphate dispersion; 2.36 g of allylamine was weighed and dissolved in 100 mL of deionized water to obtain a 0.4 mol / L tetrabutylammonium hydroxide solution, which was then slowly added dropwise to the zirconium hydrogen phosphate dispersion. Concentrated phosphoric acid was added dropwise to the above dispersion to adjust the pH to 2, and magnetically stirred at room temperature for 6 hours. Subsequently, 50 mL of 5 mg / mL caffeic acid solution was prepared and added to the zirconium hydrogen phosphate solution, and stirred at room temperature for 4 hours. Subsequently, the above solution was dialyzed with distilled water for 24 hours using a 500 Da dialysis bag to remove unreacted tannic acid, and finally an 8 mg / mL zirconium hydrogen phosphate cross-linked dispersion was obtained. Next, 10 mL of lignin water-based polyurethane with a solid content of 20% and 1.5 mL of 0.1 mg / mL rhodamine 6G solution were taken, mixed with 7.5 mL of zirconium hydrogen phosphate cross-linked dispersion and stirred at room temperature for 2 hours to obtain a bionic patterned biomass-based photoluminescent polyurethane emulsion for leather. Finally, it was loaded into a spray gun and evenly sprayed once on chrome-tanned leather with a hollow butterfly pattern. It was placed in a 50°C oven for drying and repeated 3 times to obtain a bionic patterned biomass-based photoluminescent polyurethane coating for leather. It is almost invisible in sunlight, but can display a clear light yellow butterfly pattern under 365nm ultraviolet light, and has excellent anti-counterfeiting function.

[0035] Example 5 1.6 g of zirconium hydrogen phosphate was weighed and added to 100 mL of deionized water to obtain a 0.05 mol / L zirconium hydrogen phosphate dispersion; 7.1 g of tetrabutylammonium hydroxide was weighed and dissolved in 100 mL of deionized water to obtain a 0.4 mol / L tetrabutylammonium hydroxide solution, and then the tetrabutylammonium hydroxide solution was slowly added dropwise to the zirconium hydrogen phosphate dispersion. Concentrated phosphoric acid was added dropwise to the above dispersion to adjust the pH to 1.5, and magnetic stirring was carried out at room temperature for 6 hours. Then, 48 mL of 2 mg / mL tannic acid solution was prepared and added to the zirconium hydrogen phosphate solution. It was stirred at room temperature for 4 hours, and then the above solution was dialyzed with distilled water for 24 hours using a 1000 Da dialysis bag to remove unreacted tannic acid, and finally an 8 mg / mL zirconium hydrogen phosphate cross-linked dispersion was obtained. Next, 10 mL of castor oil-based water-based polyurethane with a solid content of 20% and 2 mL of 0.1 mg / mL rhodamine B solution were taken, mixed with 5 mL of zirconium hydrogen phosphate cross-linked dispersion and stirred at room temperature for 2 hours to obtain a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather. Finally, the polyurethane emulsion was loaded into a spray gun and evenly sprayed on the vegetable tanned leather once. It was placed in a 50°C oven for drying and repeated three times to obtain a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather.

[0036] Example 6 1.6 g of zirconium hydrogen phosphate was weighed and added to 100 mL of deionized water to obtain a 0.05 mol / L zirconium hydrogen phosphate dispersion; 5.68 g of tetrabutylammonium hydroxide was weighed and dissolved in 100 mL of deionized water to obtain a 0.32 mol / L tetrabutylammonium hydroxide solution, and then the tetrabutylammonium hydroxide solution was slowly added dropwise to the zirconium hydrogen phosphate dispersion. Concentrated phosphoric acid was added dropwise to the above dispersion to adjust the pH to 2.5, and magnetically stirred at room temperature for 6 hours. Then, 36 mL of 2 mg / mL tannic acid solution was prepared and added to the zirconium hydrogen phosphate solution, and stirred at room temperature for 2 hours. Subsequently, the above solution was dialyzed with distilled water for 24 hours using a 1000 Da dialysis bag to remove unreacted tannic acid, and finally an 8 mg / mL zirconium hydrogen phosphate cross-linked dispersion was obtained. Next, 10 mL of castor oil-based water-based polyurethane with a solid content of 20% and 2 mL of 0.1 mg / mL rhodamine B solution were taken, mixed with 8.3 mL of zirconium hydrogen phosphate cross-linked dispersion and stirred at room temperature for 2 hours to obtain a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather. Finally, the polyurethane emulsion was loaded into a spray gun, evenly sprayed on the vegetable tanned leather once, and placed in a 50°C oven for drying. This was repeated 3 times to obtain a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather.

[0037] Figure 1This SEM image of the photoluminescent polyurethane film prepared according to Example 2 shows that it has a distinct structure similar to natural skin wrinkles, which contributes to its excellent adhesion properties. Because films and coatings are essentially similar, the structure of the film is often extrapolated to the coating structure.

[0038] Figure 2 (a) is a stress-strain curve of a polyurethane composite film formed by a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather prepared by Example 2 of the method for preparing a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather of the present invention (in Figure 2 (a), I: polyurethane; II: polyurethane-nanosheet; III: polyurethane-nanosheet-organic crosslinker); as can be seen from Figure 2 (a), Example 2 performs best in terms of strength and ductility, showing the highest stress and moderate strain.

[0039] Figure 2 (b) shows the toughness and Young's modulus of the polyurethane composite film formed by the biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather prepared by Example 2 of the preparation method of the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather of the present invention (in Figure 2 (b), I: polyurethane; II: polyurethane-nanosheet; III: polyurethane-nanosheet-organic crosslinker); It can be seen from Figure 2 (b) that Example 2 shows the best performance in both toughness and Young's modulus, showing the highest toughness and Young's modulus.

[0040] FIG2 (c) shows the change in fluorescence color due to different deformations of the polyurethane composite film formed by the biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather prepared by Example 2 of the method for preparing the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather of the present invention. As can be seen from FIG2 (c), under ultraviolet light, the fluorescence color becomes lighter with increasing elongation, and has mechanochromic properties.

[0041] FIG3( a ) is a photograph of the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather prepared in Example 3 taken under sunlight. FIG3( a ) shows a distinct butterfly image under normal lighting conditions. FIG3( b ) is a photograph of the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather prepared in Example 3 under ultraviolet light. FIG3( b ) shows that the polyurethane coating prepared in the present invention displays a clear butterfly image under ultraviolet light.

[0042] FIG4( a ) is a photograph of the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather prepared in Example 4 taken under sunlight. FIG4( a ) clearly shows that the coating is almost invisible to the naked eye under sunlight. FIG4( b ) is a photograph of the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather prepared in Example 4 under ultraviolet light. FIG4( b ) shows that the polyurethane coating displays a bright light yellow butterfly image under 365 nm ultraviolet light.

[0043] As can be seen from FIG3(a) and FIG3(b), and FIG4(a) and FIG4(b), the polyurethane coating prepared by the present invention can be sprayed evenly on the leather, has good follow-up performance, clear pattern display, and good anti-counterfeiting performance.

Claims

1. A method for preparing a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather, characterized in that: The specific steps include: Step 1, preparing a zirconium hydrogen phosphate crosslinked dispersion; Step 2, preparing a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather according to the product obtained in step 1; Step 3, preparing a biomimetic patterned biomass-based photoluminescent polyurethane coating for leather according to the product obtained in step 2.

2. The method for preparing the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather according to claim 1, characterized in that: The specific process of step 1 is as follows: Step 1.1, adding the stripping agent solution dropwise into the zirconium hydrogen phosphate dispersion, and stirring evenly with magnetic force at room temperature; Step 1.2, adding concentrated phosphoric acid dropwise to the zirconium hydrogen phosphate dispersion treated in step 1.1 to adjust the pH to acidic; Step 1.3, adding the organic crosslinking agent solution dropwise to the zirconium hydrogen phosphate dispersion treated in step 1.2, stirring evenly at room temperature, and finally, dialyzing with deionized water to remove unreacted crosslinking agent molecules, and finally obtaining a zirconium hydrogen phosphate crosslinked dispersion.

3. The method for preparing the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather according to claim 2, characterized in that: In the step 1.1, the molar ratio of zirconium hydrogen phosphate to the stripping agent is 1:(6-8), and the stripping agent is any one of tetrabutylammonium hydroxide, propylamine, and allylamine.

4. The method for preparing the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather according to claim 2, characterized in that: In the step 1.2, concentrated phosphoric acid is used to adjust the pH of the solution to a range of 1.5 to 2.

5.

5. The method for preparing the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather according to claim 2, characterized in that: In the step 1.3, the molar ratio of the organic cross-linking agent to zirconium hydrogen phosphate is 1:(150-200), and the organic cross-linking agent is any one of tannic acid, gallic acid, caffeic acid or dopamine.

6. The method for preparing the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather according to claim 2, characterized in that: The specific process of step 2 is: The polyurethane solution, the fluorescent agent and the zirconium hydrogen phosphate cross-linked dispersion prepared in step 1 are mixed, and magnetic stirring is performed evenly at room temperature to obtain a biomimetic patterned biomass-based photoluminescent polyurethane emulsion for leather.

7. The method for preparing the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather according to claim 6, characterized in that: In the step 2, the mass ratio of the polyurethane solution to the zirconium hydrogen phosphate crosslinked dispersion and the fluorescent agent is 1:0.01-0.05:0.00005-0.00015.

8. The method for preparing the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather according to claim 7, characterized in that: In the step 2, the polyurethane is any one of castor oil-based polyurethane, sorbitol-based polyurethane or lignin-based polyurethane, and the solid content of the polyurethane in the polyurethane solution is 20%; the fluorescent agent is any one of rhodamine 6G, rhodamine B or fluorescein.

9. The method for preparing the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather according to claim 7, characterized in that: The specific process of step 3 is: take the product obtained in step 2 and put it into a spray gun, spray it on the leather surface that fits the hollow pattern, and finally place the sprayed leather in an oven. After the water is completely evaporated, the bionic patterned coating for leather is obtained.

10. A biomimetic patterned biomass-based photoluminescent polyurethane coating for leather, prepared by the method for preparing the biomimetic patterned biomass-based photoluminescent polyurethane coating for leather according to any one of claims 1 to 9.

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