Nanometer silicon oxide enhanced high-brightness waterborne polyurethane gloss oil and preparation method thereof

Abstract

The invention discloses nano silicon oxide enhanced high-brightness waterborne polyurethane gloss oil and a preparation method thereof, and belongs to the technical field of surface printing materials, the nano silicon oxide enhanced high-brightness waterborne polyurethane gloss oil comprises the following raw materials by weight: 100-200 parts of modified waterborne polyurethane; 35 to 46 parts of nano silicon dioxide aerogel particles modified by silver citrate; 5 to 10 parts of vanillin; 6 to 9 parts of isosorbide; 4 to 9 parts of ethylenediamine tetraacetic acid; 2 to 6 parts of fluoro-polyether modified polysiloxane; 1-4 parts of a water-based defoaming agent; 20 to 30 parts of water; the preparation method of the silver citrate modified nano silicon dioxide aerogel particles comprises the following steps: heating and baking silicon dioxide aerogel twice, freezing, crushing, mixing with a silver citrate solution, heating for surface modification, treating with liquid carbon dioxide, drying and grinding. Through the mode, the nano silicon oxide enhanced high-brightness waterborne polyurethane gloss oil prepared by the invention has the advantages of good friction resistance, high glossiness, good scratch resistance, good high temperature resistance and the like.

Description

Technical Field

[0001] The invention relates to the technical field of surface printing materials, and in particular to a nano-silicon oxide-enhanced high-gloss water-based polyurethane varnish and a preparation method thereof. Background Art

[0002] High-end packaging materials (cardboard) are printed with different colors of ink to showcase product features and characteristics. Because cardboard is inherently hard, it presents a risk of scratching during both the production and packaging process, as well as during use. This can lead to discoloration and scratches on the product surface, affecting the product's appearance. A common solution is to apply UV varnish to the cardboard surface, but this still poses issues such as residual odor after curing and difficulty in degradation.

[0003] CN111455719A discloses a high-gloss water-based polyurethane varnish for polishing gold and silver cardboard surfaces and its preparation method. The varnish is composed of the following ingredients: 40-60% water-based aliphatic high-hardness polyurethane; 20-40% water-based glossy polycarbonate polyurethane; 0.5-3% water-based film-forming aid; 5-15% water-based additives; and 3-8% purified water. The water-based additives include water-based defoamers TEGO1488 and DF7072, a water-based thickener, a water-based wear-resistant wax paste (water-based polyethylene wax paste), a water-based slip agent (polyether siloxane copolymer), water-based leveling agents DAPRO-77 and Surfynol 420, a water-based pH regulator, and a water-based crosslinker. This product addresses the problems of strong residual odor from UV varnish coatings and the inability of traditional water-based acrylic wear-resistant varnishes to meet wear-resistant environments, thus meeting environmental protection requirements.

[0004] The aforementioned polyurethane varnish utilizes a water-based polyethylene wax slurry and a polyether siloxane copolymer to improve the system's scratch and abrasion resistance, while also reducing the coefficient of friction. The effect of the water-based polyethylene wax slurry on the varnish's abrasion resistance and gloss is related to the wax's particle size. Increasing the particle size improves abrasion resistance but also significantly reduces glossiness. Smaller particle sizes enhance gloss but also reduce abrasion resistance. Therefore, it's important to carefully select the particle size of the water-based polyethylene wax to strike a balance between abrasion resistance and gloss. The polyether siloxane copolymer, on the other hand, primarily reduces the coefficient of friction and has a lesser effect on scratch and abrasion resistance.

[0005] Based on this, the present invention designs a nano-silicon oxide enhanced high-gloss water-based polyurethane varnish and a preparation method thereof to solve the above problems. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a nano-silicon oxide enhanced high-gloss water-based polyurethane varnish and a preparation method thereof.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] A nano-silicon oxide enhanced high-gloss water-based polyurethane varnish comprising the following raw materials in parts by weight:

[0009] 100-200 parts of modified waterborne polyurethane;

[0010] 35-46 parts of silver citrate-modified nano-silica aerogel particles;

[0011] 5-10 parts of vanillin;

[0012] 6-9 parts of isosorbide;

[0013] 4-9 parts of ethylenediaminetetraacetic acid;

[0014] 2-6 parts of fluorine-based polyether modified polysiloxane;

[0015] 1 to 4 parts of aqueous defoaming agent;

[0016] 20-30 parts water;

[0017] The modified waterborne polyurethane is prepared from ε-caprolactone, hyperbranched polyurethane acrylate, polybutylene succinate, hydroxy-terminated polybutadiene, isosorbide, and γ-methacryloyloxypropyltrimethoxysilane;

[0018] The preparation method of the silver citrate-modified nano-silica aerogel particles comprises the following steps: heating and baking the silica aerogel twice, freezing and crushing the silica aerogel, mixing the silica aerogel with a silver citrate solution, heating the aerogel to perform surface modification, treating the aerogel with liquid carbon dioxide, drying the aerogel, and grinding the aerogel.

[0019] Furthermore, the preparation method of the modified waterborne polyurethane is as follows: 12 to 15 parts of ε-caprolactone, 58 to 85 parts of hyperbranched polyurethane acrylate, and 7 to 12 parts of polybutylene succinate are added into a reactor to obtain an ε-caprolactone modified polyurethane copolymer; 3 to 5.5 parts of hydroxy-terminated polybutadiene, 2 to 5 parts of isosorbide, and 8 to 13 parts of γ-methacryloxypropyltrimethoxysilane are added into the reactor, reacting at room temperature for 2 to 4 hours, heating to 65 to 70°C and stirring for 2 to 3 hours, and stirring at a speed of 500 to 800 r / min.

[0020] Furthermore, the specific steps of the two temperature baking are: 20 to 40 parts of silica aerogel are placed at 150 to 220°C and baked for 1 to 2 hours at a heating rate of 20 to 30°C / min, and then heated to 500 to 600°C and calcined for 15 to 20 minutes at a heating rate of 10 to 20°C / min.

[0021] Furthermore, the specific steps of freezing and crushing are: freezing at 0-3°C for 2-3 hours, and crushing to 200-300 nm.

[0022] Furthermore, the specific steps of surface modification are: preparing 50-60 parts of a silver citrate solution with a concentration of 25-30w%, adding the silica aerogel to the silver citrate solution and mixing, heating to 105-110°C and stirring for 1-1.5 hours at a stirring speed of 1200-1500 r / min to perform surface modification.

[0023] In order to better achieve the purpose of the present invention, the present invention also provides a method for preparing a nano-silicon oxide enhanced high-gloss water-based polyurethane varnish, comprising the following steps:

[0024] Step 1, preparing modified waterborne polyurethane;

[0025] Step 2: preparing silver citrate-modified nano-silica aerogel particles;

[0026] Step 3: Place 20-30 parts of water, 100-200 parts of modified waterborne polyurethane, 2-6 parts of fluorine-based polyether-modified polysiloxane, 4-9 parts of ethylenediaminetetraacetic acid, and 35-46 parts of silver citrate-modified nano-silica aerogel particles into a disperser and disperse at a speed of 1000-1200 r / min for 40-60 minutes;

[0027] Step 4: Place 5-10 parts of vanillin, 6-9 parts of isosorbide and 1-4 parts of aqueous defoamer into a disperser and disperse at a speed of 2000-2500 r / min for 25-40 minutes to obtain nano-silicon oxide enhanced high-gloss water-based polyurethane varnish.

[0028] Furthermore, step one specifically includes the following steps: adding 12 to 15 parts of ε-caprolactone, 58 to 85 parts of hyperbranched polyurethane acrylate, and 7 to 12 parts of polybutylene succinate into a reactor to obtain an ε-caprolactone-modified polyurethane copolymer; adding 3 to 5.5 parts of hydroxy-terminated polybutadiene, 2 to 5 parts of isosorbide, and 8 to 13 parts of γ-methacryloxypropyltrimethoxysilane into the reactor, reacting at room temperature for 2 to 4 hours, and heating to 65 to 70° C. and stirring for reaction for 2 to 3 hours.

[0029] Furthermore, step 2 specifically includes the following steps: taking 20 to 40 parts of silica aerogel and baking them at 150 to 220°C for 1 to 2 hours at a heating rate of 20 to 30°C / min, then heating them to 500 to 600°C and calcining them for 15 to 20 minutes at a heating rate of 10 to 20°C / min, then freezing them at 0 to 3°C for 2 to 3 hours, and crushing them to 200 to 300 nm; preparing 50 to 60 parts of a silver citrate solution with a concentration of 25 to 30w%, placing the silica aerogel in the silver citrate solution and mixing, heating it to 105 to 110°C and stirring for 1 to 1.5 hours at a stirring rate of 1200 to 1500 r / min, performing surface modification, treating it with liquid carbon dioxide in a high-pressure device, drying and grinding it to obtain silver citrate-modified nano-silica aerogel particles.

[0030] Furthermore, in step 2, the particles are ground to a thickness of 80 to 100 nm.

[0031] Furthermore, in step 1, the stirring speed is 500-800 r / min.

[0032] Compared with the prior art, the present invention has the following beneficial effects: the nano-silica-enhanced high-gloss water-based polyurethane varnish prepared by the present invention is prepared by using water, modified water-based polyurethane, fluorine-based polyether-modified polysiloxane, ethylenediaminetetraacetic acid and silver citrate-modified nano-silica aerogel particles, vanillin, isosorbide and water-based defoaming agent; the nano-silica aerogel particles are not modified, and the adhesion, hardness, friction resistance, scratch resistance and high-temperature resistance of the varnish are significantly reduced. The reason may be that after silver citrate modifies the surface of the nano-silica aerogel particles, the dispersibility, surface hardness, wear resistance and thermal stability of the nano-silica aerogel particles are improved, and then filled in the polymer network structure of the water-based polyurethane varnish, so that the water-based polyurethane varnish has the advantages of good friction resistance, high gloss, good scratch resistance, good high-temperature resistance and the like. Freezing after two heating and baking steps and treatment with liquid carbon dioxide have a significant impact on the hardness, friction resistance, scratch resistance and high temperature resistance of the product. The reason may be that the secondary heating increases the pore size inside the silica aerogel particles, and low temperature is conducive to increasing the fixation of the internal morphology of the aerogel particles, thereby increasing the number and strength of the binding with silver citrate. The silver citrate-modified nano-silica aerogel particles formed after the composite are conducive to improving the hardness, friction resistance, scratch resistance and high temperature resistance of the product. DETAILED DESCRIPTION

[0033] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Example 1

[0035] In some embodiments, a method for preparing a nano-silicon oxide enhanced high-gloss water-based polyurethane varnish comprises the following steps:

[0036] Step 1, preparing modified waterborne polyurethane;

[0037] 12 parts of ε-caprolactone, 85 parts of hyperbranched polyurethane acrylate, and 7 parts of polybutylene succinate were added to the reactor to obtain an ε-caprolactone-modified polyurethane copolymer; 5.5 parts of hydroxy-terminated polybutadiene, 2 parts of isosorbide, and 13 parts of γ-methacryloxypropyltrimethoxysilane were added to the reactor, and the mixture was reacted at room temperature for 2 hours, and then the temperature was raised to 70°C and stirred for 2 hours at a stirring speed of 800 r / min.

[0038] Step 2: preparing silver citrate-modified nano-silica aerogel particles;

[0039] 20 parts of silica aerogel are baked at 220°C for 1 hour at a heating rate of 30°C / min, then heated to 500°C and calcined for 20 minutes at a heating rate of 10°C / min, then frozen at 3°C ​​for 2 hours, and crushed to 300 nm; 60 parts of a 25w% silver citrate solution are prepared, the silica aerogel is placed in the silver citrate solution and mixed, the mixture is heated to 105°C and stirred for 1.5 hours at a stirring rate of 1200 r / min, surface modified, treated with liquid carbon dioxide in a high-pressure device, dried, and ground to 100 nm to obtain silver citrate-modified nano-silica aerogel particles.

[0040] Step 3: Put 20 parts of water, 200 parts of modified waterborne polyurethane, 2 parts of fluorine-based polyether-modified polysiloxane, 9 parts of ethylenediaminetetraacetic acid and 35 parts of silver citrate-modified nano-silica aerogel particles into a disperser and disperse at a speed of 1200 r / min for 40 minutes.

[0041] Step 4: Place 5 parts of vanillin, 9 parts of isosorbide and 1 part of aqueous defoamer into a disperser and disperse at a speed of 2500 r / min for 25 minutes to obtain nano-silicon oxide enhanced high-gloss water-based polyurethane varnish.

[0042] The prepared nano-silicon oxide enhanced high-gloss water-based polyurethane varnish was printed on cardboard and dried with hot air. Its performance met the use requirements:

[0043] Adhesion (GB / T 13217.7-2023): 98.4%.

[0044] Hardness (GB / T 6739-2022): 4H;

[0045] Friction resistance (GB / T 7706-2008): 780 times;

[0046] Gloss (GB / T 9754-2007): 98.6 (60°);

[0047] Scratch resistance (GB / T 9279.1-2015, coating thickness 10μm): 9N;

[0048] The prepared nano-silicon oxide-enhanced high-gloss water-based polyurethane varnish was printed on iron parts and dried with hot air to form a coating film. Its high-temperature resistance was tested (the coating film was baked at 350°C for 3 hours and the state of the coating film was observed): no cracking.

[0049] Example 2

[0050] In some embodiments, a method for preparing a nano-silicon oxide enhanced high-gloss water-based polyurethane varnish comprises the following steps:

[0051] Step 1, preparing modified waterborne polyurethane;

[0052] 15 parts of ε-caprolactone, 58 parts of hyperbranched polyurethane acrylate, and 12 parts of polybutylene succinate were added to the reactor to obtain an ε-caprolactone-modified polyurethane copolymer; 3 parts of terminal hydroxyl polybutadiene, 5 parts of isosorbide, and 8 parts of γ-methacryloxypropyltrimethoxysilane were added to the reactor, and the mixture was reacted at room temperature for 4 hours, and then the temperature was raised to 65°C and stirred for 3 hours at a stirring speed of 500 r / min.

[0053] Step 2: preparing silver citrate-modified nano-silica aerogel particles;

[0054] 40 parts of silica aerogel are baked at 150°C for 2 hours at a heating rate of 20°C / min, then heated to 600°C and calcined for 15 minutes at a heating rate of 20°C / min, then frozen at 0°C for 3 hours, and crushed to 200 nm; 50 parts of a 30w% silver citrate solution are prepared, the silica aerogel is placed in the silver citrate solution and mixed, the mixture is heated to 110°C and stirred for 1 hour at a stirring rate of 1500 r / min, surface modified, treated with liquid carbon dioxide in a high-pressure device, dried, and ground to 80 nm to obtain silver citrate-modified nano-silica aerogel particles.

[0055] Step 3: Put 30 parts of water, 100 parts of modified waterborne polyurethane, 6 parts of fluorine-based polyether-modified polysiloxane, 4 parts of ethylenediaminetetraacetic acid and 46 parts of silver citrate-modified nano-silica aerogel particles into a disperser and disperse at a speed of 1000 r / min for 60 minutes.

[0056] Step 4: Put 10 parts of vanillin, 6 parts of isosorbide and 4 parts of aqueous defoamer into a disperser and disperse them at a speed of 2000 r / min for 40 minutes to obtain nano-silicon oxide enhanced high-gloss water-based polyurethane varnish.

[0057] The prepared nano-silicon oxide enhanced high-gloss water-based polyurethane varnish was printed on cardboard and dried with hot air. Its performance met the use requirements:

[0058] Adhesion (GB / T 13217.7-2023): 99.1%.

[0059] Hardness (GB / T 6739-2022): 3H;

[0060] Friction resistance (GB / T 7706-2008): 692 times;

[0061] Gloss (GB / T 9754-2007): 99.4 (60°);

[0062] Scratch resistance (GB / T 9279.1-2015, coating thickness 10μm): 10N;

[0063] The prepared nano-silicon oxide-enhanced high-gloss water-based polyurethane varnish was printed on iron parts and dried with hot air to form a coating film. Its high-temperature resistance was tested (the coating film was baked at 350°C for 3 hours and the state of the coating film was observed): no cracking.

[0064] Example 3

[0065] In some embodiments, a method for preparing a nano-silicon oxide enhanced high-gloss water-based polyurethane varnish comprises the following steps:

[0066] Step 1, preparing modified waterborne polyurethane;

[0067] 13 parts of ε-caprolactone, 75 parts of hyperbranched polyurethane acrylate, and 10 parts of polybutylene succinate were added to the reactor to obtain an ε-caprolactone-modified polyurethane copolymer; 3.5 parts of terminal hydroxyl polybutadiene, 4 parts of isosorbide, and 10 parts of γ-methacryloxypropyltrimethoxysilane were added to the reactor, and the mixture was reacted at room temperature for 3 hours, and then the temperature was raised to 68°C and stirred for reaction for 2.3 hours at a stirring speed of 700 r / min.

[0068] Step 2: preparing silver citrate-modified nano-silica aerogel particles;

[0069] 30 parts of silica aerogel were baked at 180°C for 1.3 hours at a heating rate of 25°C / min, then heated to 550°C and calcined for 18 minutes at a heating rate of 18°C / min, then frozen at 1°C for 2.6 hours, and crushed to 250 nm. 55 parts of a 28w% silver citrate solution were prepared, and the silica aerogel was placed in the silver citrate solution and mixed. The mixture was heated to 108°C and stirred for 1.3 hours at a stirring rate of 1300 r / min for surface modification. After being treated with liquid carbon dioxide in a high-pressure device, the particles were dried and ground to 90 nm to obtain silver citrate-modified nano-silica aerogel particles.

[0070] Step 3: Put 25 parts of water, 160 parts of modified waterborne polyurethane, 4 parts of fluorine-based polyether-modified polysiloxane, 5 parts of ethylenediaminetetraacetic acid and 42 parts of silver citrate-modified nano-silica aerogel particles into a disperser and disperse at a speed of 1100 r / min for 50 minutes.

[0071] Step 4: Put 8 parts of vanillin, 7 parts of isosorbide and 2 parts of aqueous defoamer into a disperser and disperse them at a speed of 2200 r / min for 30 minutes to obtain nano-silicon oxide enhanced high-gloss water-based polyurethane varnish.

[0072] The prepared nano-silicon oxide enhanced high-gloss water-based polyurethane varnish was printed on cardboard and dried with hot air. Its performance met the use requirements:

[0073] Adhesion (GB / T 13217.7-2023): 98.6%.

[0074] Hardness (GB / T 6739-2022): 4H;

[0075] Friction resistance (GB / T 7706-2008): 816 times;

[0076] Gloss (GB / T 9754-2007): 97.5 (60°);

[0077] Scratch resistance (GB / T 9279.1-2015, coating thickness 10μm): 9N;

[0078] The prepared nano-silicon oxide-enhanced high-gloss water-based polyurethane varnish was printed on iron parts and dried with hot air to form a coating film. Its high-temperature resistance was tested (the coating film was baked at 350°C for 3 hours and the state of the coating film was observed): no discoloration and no cracking.

[0079] Comparative Example 1

[0080] Different from Example 3, the nano-silica aerogel particles are not modified.

[0081] In some embodiments, a method for preparing a nano-silicon oxide enhanced high-gloss water-based polyurethane varnish comprises the following steps:

[0082] Step 1, preparing modified waterborne polyurethane;

[0083] 13 parts of ε-caprolactone, 75 parts of hyperbranched polyurethane acrylate, and 10 parts of polybutylene succinate were added to the reactor to obtain an ε-caprolactone-modified polyurethane copolymer; 3.5 parts of terminal hydroxyl polybutadiene, 4 parts of isosorbide, and 10 parts of γ-methacryloxypropyltrimethoxysilane were added to the reactor, and the mixture was reacted at room temperature for 3 hours, and then the temperature was raised to 68°C and stirred for reaction for 2.3 hours at a stirring speed of 700 r / min.

[0084] Step 2: Put 25 parts of water, 160 parts of modified waterborne polyurethane, 4 parts of fluorine-based polyether-modified polysiloxane, 5 parts of ethylenediaminetetraacetic acid and 42 parts of 90 nm nano-silica aerogel particles into a disperser and disperse at a speed of 1100 r / min for 50 minutes.

[0085] Step 3: Place 8 parts of vanillin, 7 parts of isosorbide and 2 parts of aqueous defoamer into a disperser and disperse at a speed of 2200 r / min for 30 minutes to obtain nano-silicon oxide enhanced high-gloss water-based polyurethane varnish.

[0086] The prepared nano-silicon oxide enhanced high-gloss water-based polyurethane varnish was printed on cardboard and dried with hot air. Its performance met the use requirements:

[0087] Adhesion (GB / T 13217.7-2023): 94.4%.

[0088] Hardness (GB / T 6739-2022): 3H;

[0089] Friction resistance (GB / T 7706-2008): 405 times;

[0090] Gloss (GB / T 9754-2007): 98.1 (60°);

[0091] Scratch resistance (GB / T 9279.1-2015, coating thickness 10μm): 5N;

[0092] The prepared nano-silicon oxide enhanced high-gloss water-based polyurethane varnish was printed on iron parts and dried with hot air to form a coating film. Its high temperature resistance was tested (the coating film was baked at 350°C for 3 hours and the state of the coating film was observed): discoloration and slight cracking.

[0093] Comparative Example 2

[0094] The difference from Example 3 is that the method for preparing silver citrate-modified nano-silica aerogel particles is different.

[0095] In some embodiments, a method for preparing a nano-silicon oxide enhanced high-gloss water-based polyurethane varnish comprises the following steps:

[0096] Step 1, preparing modified waterborne polyurethane;

[0097] 13 parts of ε-caprolactone, 75 parts of hyperbranched polyurethane acrylate, and 10 parts of polybutylene succinate were added to the reactor to obtain an ε-caprolactone-modified polyurethane copolymer; 3.5 parts of terminal hydroxyl polybutadiene, 4 parts of isosorbide, and 10 parts of γ-methacryloxypropyltrimethoxysilane were added to the reactor, and the mixture was reacted at room temperature for 3 hours, and then the temperature was raised to 68°C and stirred for reaction for 2.3 hours at a stirring speed of 700 r / min.

[0098] Step 2: preparing silver citrate-modified nano-silica aerogel particles;

[0099] 30 parts of silica aerogel were baked at 550°C for 1.6 hours at a heating rate of 18°C / min, and then crushed to 250 nm; 55 parts of a 28w% silver citrate solution were prepared, the silica aerogel was placed in the silver citrate solution and mixed, the mixture was heated to 108°C and stirred for 1.3 hours at a stirring rate of 1300 r / min, surface modified, dried, and ground to 90 nm to obtain silver citrate-modified nano-silica aerogel particles.

[0100] Step 3: Put 25 parts of water, 160 parts of modified waterborne polyurethane, 4 parts of fluorine-based polyether-modified polysiloxane, 5 parts of ethylenediaminetetraacetic acid and 42 parts of silver citrate-modified nano-silica aerogel particles into a disperser and disperse at a speed of 1100 r / min for 50 minutes.

[0101] Step 4: Put 8 parts of vanillin, 7 parts of isosorbide and 2 parts of aqueous defoamer into a disperser and disperse them at a speed of 2200 r / min for 30 minutes to obtain nano-silicon oxide enhanced high-gloss water-based polyurethane varnish.

[0102] The prepared nano-silicon oxide enhanced high-gloss water-based polyurethane varnish was printed on cardboard and dried with hot air. Its performance met the use requirements:

[0103] Adhesion (GB / T 13217.7-2023): 96.9%.

[0104] Hardness (GB / T 6739-2022): 3H;

[0105] Friction resistance (GB / T 7706-2008): 489 times;

[0106] Gloss (GB / T 9754-2007): 97.1 (60°);

[0107] Scratch resistance (GB / T 9279.1-2015, coating thickness 10μm): 6N;

[0108] The prepared nano-silicon oxide-enhanced high-gloss water-based polyurethane varnish was printed on iron parts and dried with hot air to form a coating film. Its high-temperature resistance was tested (the coating film was baked at 350°C for 3 hours and the state of the coating film was observed): no discoloration, slight cracking.

[0109] The nano-silica-enhanced high-gloss water-based polyurethane varnish prepared by the present invention is prepared by using water, modified water-based polyurethane, fluorine-based polyether-modified polysiloxane, nano-silica aerogel particles modified with ethylenediaminetetraacetic acid and silver citrate, vanillin, isosorbide and an aqueous defoaming agent. It can be seen from Comparative Example 1 that when the nano-silica aerogel particles are not modified, the adhesion, hardness, friction resistance, scratch resistance and high-temperature resistance of the varnish are significantly reduced. The reason may be that after the silver citrate modifies the surface of the nano-silica aerogel particles, the dispersibility, surface hardness, wear resistance and thermal stability of the nano-silica aerogel particles are improved, and then the silver citrate is filled in the polymer network structure of the water-based polyurethane varnish, so that the water-based polyurethane varnish has the advantages of good friction resistance, high gloss, good scratch resistance, good high-temperature resistance and the like. It can be seen from Comparative Example 2 that freezing after two heating and baking and treatment with liquid carbon dioxide have a great influence on the hardness, friction resistance, scratch resistance and high temperature resistance of the product. The reason may be that the secondary heating increases the pore size inside the silica aerogel particles, and the low temperature is conducive to increasing the fixation of the internal morphology of the aerogel particles, thereby increasing the number and strength of the binding with silver citrate. The silver citrate-modified nano-silica aerogel particles formed after the composite are beneficial to improving the hardness, friction resistance, scratch resistance and high temperature resistance of the product.

[0110] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A nano-silicon oxide enhanced high-gloss water-based polyurethane varnish, characterized in that: The composition comprises the following raw materials in parts by weight: 100-200 parts of modified waterborne polyurethane; 35-46 parts of silver citrate-modified nano-silica aerogel particles; 5-10 parts of vanillin; 6-9 parts of isosorbide; 4-9 parts of ethylenediaminetetraacetic acid; 2-6 parts of fluorine-based polyether modified polysiloxane; 1 to 4 parts of aqueous defoaming agent; 20-30 parts water; The modified waterborne polyurethane is prepared from ε-caprolactone, hyperbranched polyurethane acrylate, polybutylene succinate, hydroxy-terminated polybutadiene, isosorbide, and γ-methacryloyloxypropyltrimethoxysilane; The preparation method of the silver citrate-modified nano-silica aerogel particles comprises the following steps: heating and baking the silica aerogel twice, freezing and crushing the silica aerogel, mixing the silica aerogel with a silver citrate solution, heating the aerogel to perform surface modification, treating the aerogel with liquid carbon dioxide, drying the aerogel, and grinding the aerogel.

2. The nano-silicon oxide enhanced high-gloss water-based polyurethane varnish according to claim 1, characterized in that: The preparation method of the modified waterborne polyurethane comprises the following steps: adding 12 to 15 parts of ε-caprolactone, 58 to 85 parts of hyperbranched polyurethane acrylate, and 7 to 12 parts of polybutylene succinate into a reactor to obtain an ε-caprolactone-modified polyurethane copolymer; adding 3 to 5.5 parts of hydroxy-terminated polybutadiene, 2 to 5 parts of isosorbide, and 8 to 13 parts of gamma-methacryloxypropyltrimethoxysilane into the reactor, reacting at room temperature for 2 to 4 hours, heating to 65 to 70° C., stirring and reacting for 2 to 3 hours at a stirring speed of 500 to 800 r / min.

3. The nano-silicon oxide enhanced high-gloss water-based polyurethane varnish according to claim 2, characterized in that: The specific steps of the two temperature baking are: baking 20 to 40 parts of silica aerogel at 150 to 220°C for 1 to 2 hours at a heating rate of 20 to 30°C / min, and then heating to 500 to 600°C and calcining for 15 to 20 minutes at a heating rate of 10 to 20°C / min.

4. The nano-silicon oxide enhanced high-gloss water-based polyurethane varnish according to claim 3, characterized in that: The specific steps of freezing and crushing are: freezing at 0-3°C for 2-3 hours, and crushing to 200-300 nm.

5. The nano-silicon oxide enhanced high-gloss water-based polyurethane varnish according to claim 4, characterized in that: The specific steps of surface modification are: preparing 50-60 parts of a silver citrate solution with a concentration of 25-30w%, adding silica aerogel to the silver citrate solution and mixing, heating to 105-110°C and stirring for 1-1.5 hours at a stirring speed of 1200-1500 r / min to perform surface modification.

6. A method for preparing nano-silicon oxide enhanced high-gloss water-based polyurethane varnish, characterized in that: The following steps are involved: Step 1, preparing modified waterborne polyurethane; Step 2: preparing silver citrate-modified nano-silica aerogel particles; Step 3: Place 20-30 parts of water, 100-200 parts of modified waterborne polyurethane, 2-6 parts of fluorine-based polyether-modified polysiloxane, 4-9 parts of ethylenediaminetetraacetic acid, and 35-46 parts of silver citrate-modified nano-silica aerogel particles into a disperser and disperse at a speed of 1000-1200 r / min for 40-60 minutes; Step 4: Place 5-10 parts of vanillin, 6-9 parts of isosorbide and 1-4 parts of aqueous defoamer into a disperser and disperse at a speed of 2000-2500 r / min for 25-40 minutes to obtain nano-silicon oxide enhanced high-gloss water-based polyurethane varnish.

7. The method for preparing the nano-silicon oxide enhanced high-gloss water-based polyurethane varnish according to claim 6, characterized in that: Step 1 specifically includes the following steps: adding 12 to 15 parts of ε-caprolactone, 58 to 85 parts of hyperbranched polyurethane acrylate, and 7 to 12 parts of polybutylene succinate into a reactor to obtain an ε-caprolactone-modified polyurethane copolymer; adding 3 to 5.5 parts of hydroxy-terminated polybutadiene, 2 to 5 parts of isosorbide, and 8 to 13 parts of γ-methacryloxypropyltrimethoxysilane into the reactor, reacting at room temperature for 2 to 4 hours, heating to 65 to 70° C. and stirring for reaction for 2 to 3 hours.

8. The method for preparing the nano-silicon oxide enhanced high-gloss water-based polyurethane varnish according to claim 7, characterized in that: The second step specifically includes the following steps: taking 20 to 40 parts of silica aerogel and baking them at 150 to 220° C. for 1 to 2 hours at a heating rate of 20 to 30° C. / min, then heating them to 500 to 600° C. and calcining them at a heating rate of 10 to 20° C. / min, then freezing them at 0 to 3° C. for 2 to 3 hours, and crushing them to 200 to 300 nm; preparing 50 to 60 parts of a silver citrate solution with a concentration of 25 to 30 w%, adding the silica aerogel to the silver citrate solution and mixing them, heating them to 105 to 110° C. and stirring them for 1 to 1.5 hours at a stirring rate of 1200 to 1500 r / min, performing surface modification, treating them with liquid carbon dioxide in a high-pressure device, drying and grinding them to obtain silver citrate-modified nano-silica aerogel particles.

9. The method for preparing the nano-silicon oxide enhanced high-gloss water-based polyurethane varnish according to claim 8, characterized in that: In step 2, the particles are ground to a thickness of 80 to 100 nm.

10. The method for preparing the nano-silicon oxide enhanced high-gloss water-based polyurethane varnish according to claim 9, characterized in that: In step 1, the stirring speed is 500-800 r / min.