A durable functional finishing method for polyurethane imitation leather coating based on nanoparticles

Abstract

The invention discloses a method for functional finishing of polyurethane imitation leather coating durability based on nanoparticles, which solves the problems of difficult control of polymerization process and complicated operation when functional finishing agent is grafted on polyurethane body, and poor functional durability when functional finishing agent is blended with polyurethane or coated on polyurethane surface. The method mainly comprises spraying finishing liquid with uniform nanoparticle dispersion onto the surface of polyurethane coating, driving the fusion of bottom layer polyurethane and surface layer nanoparticles through preheating treatment, and then driving polyurethane chain segments to approach each other through heat curing process, and at the same time firmly fixing nanoparticles in polyurethane imitation leather coating in full or semi-encapsulation mode, so as to realize the functional durability of polyurethane imitation leather coating.

Description

Technical Field

[0001] The invention belongs to the field of polyurethane functional coatings for textiles, and in particular relates to a method for finishing the durability function of polyurethane imitation leather coatings based on nanoparticles. Background Art

[0002] Polyurethane imitation leather coating is a high-performance coating material with excellent adhesion, wear resistance, stain resistance and other advantages. At present, polyurethane imitation leather fabrics are usually made by polyurethane coating and are widely used in many fields such as car seats, furniture equipment, textiles and clothing. In order to meet the needs of different applications, research and technical personnel have developed a series of methods for functional finishing of polyurethane coatings.

[0003] CN102304852B adds bamboo vinegar, an effective antibacterial ingredient, to a polyurethane coating agent, and adjusts the properties of the coating by means of a softener and a thickener to obtain an antibacterial finishing liquid, bakes at 75 to 95°C for 3 to 5 minutes to set the liquid, and then bakes at 120 to 180°C for 3 to 5 minutes to cross-link the liquid, thereby obtaining an antibacterial polyurethane coating.

[0004] CN103696265A bakes the fabric impregnated with the anti-migration agent aqueous solution, then impregnates it with the waterproof and oil-proof agent emulsion, then bakes it, and finally performs polyurethane coating finishing on the reverse side of the baked fabric to obtain a polyurethane functional coating.

[0005] CN115449255A prepares super-hydrophobic modified silica nanoparticles by adding trimethylchlorosilane during the hydrolysis of tetramethyl orthosilicate in monomer form, and adding hexamethyldisilazane, an alcohol solvent and methyltrimethoxysilane during the condensation of the hydrolyzed tetramethyl orthosilicate. The modified silica nanoparticles, ethylene glycol, dihydroxy polyester, 4,4'-diphenylmethane diisocyanate and a polyurethane solution are then mixed to prepare a super-hydrophobic polyurethane coating liquid.

[0006] The above methods mainly introduce functional finishing agents into the polyurethane coating or cover the surface by mechanical blending or applying functional components first and then coating polyurethane, thereby giving the polyurethane coating functionality. This method is easy to operate. However, these methods are difficult to balance the performance and functional durability of the polyurethane coating. Among them, the method of applying functional components first and then coating polyurethane does not affect the film formation of the polyurethane coating, but its functional components have no additional cross-linking and its durability is poor. The mechanical blending method often increases its functional durability by increasing its coating amount, but it is easy to cause uneven film formation of the polyurethane coating, resulting in a decrease in its mechanical properties and a worse feel.

[0007] In addition, CN112646110A synthesizes the gemini quaternary ammonium salt diol monomer with antimicrobial properties, and then introduces it into polyurethane in the form of chain extender on molecular level by addition reaction of polyurethane prepolymers such as gemini quaternary ammonium salt diol and diisocyanate, and obtains a kind of antimicrobial polyurethane coating material formed by polymerization containing functional monomers. Although this method solves the problem of polyurethane coating functional durability skillfully, the synthesis of its functional monomers is complicated, difficult for mass production, and its polymerization process is difficult to control. For the problems such as poor functional durability, complex preparation of functional components existing in existing polyurethane coating functional finishing technology, develop a kind of polyurethane imitation leather coating durability finishing method with simple process, environmental friendliness, excellent functional durability and functions such as anti-ultraviolet and antibacterial, which has practical application significance to the field of textile polyurethane functional coating. Summary of the invention

[0008] The present invention aims to provide a method for functional finishing of polyurethane imitation leather coating based on nanoparticles. Aiming at the defects in the prior art, a method for functional finishing of polyurethane imitation leather coating with simple process, environmental friendliness, excellent functional durability and anti-ultraviolet, antibacterial and other functions is developed.

[0009] In order to solve the above technical problems, the following technical solutions are adopted:

[0010] A method for improving the durability of a polyurethane imitation leather coating based on nanoparticles, characterized by comprising the following steps:

[0011] (1) adding the nanoparticles into a polar solvent containing a dispersant, and ultrasonicating for 20 to 60 minutes to obtain a uniformly dispersed functional finishing liquid;

[0012] (2) setting the spray gun pressure to 0.3-0.6 MPa, spraying the functional finishing liquid on the evenly spread surface of the waterborne polyurethane to obtain a functional polyurethane imitation leather coating precursor;

[0013] (3) Under certain humidity conditions, the functional polyurethane imitation leather coating precursor is preheated to drive the fusion of the bottom layer polyurethane and the surface layer nanoparticles;

[0014] (4) thermally curing the functional polyurethane imitation leather coating precursor after preheating treatment, driving the polyurethane chain segments to approach each other through solvent evaporation, completing the full or half coverage of the nanoparticles by the polyurethane coating, and preparing a functional and durable polyurethane imitation leather coating.

[0015] After optimization, the nanoparticles are hydrophilic nanoparticles with a particle size of 8 to 100 nm, and are selected from one or more of nano-titanium oxide particles, nano-zinc oxide particles, nano-silicon dioxide particles, hydroxylated carbon nanotube particles, carboxylated carbon nanotube particles, nano-silver particles, nano-basic copper sulfate particles, nano-copper sulfide particles, and nano-iron oxide particles. The nano-titanium oxide particles and nano-zinc oxide particles can give the finishing liquid anti-ultraviolet, antibacterial, self-cleaning and other functions; the nano-silicon dioxide particles can give the finishing liquid anti-aging, waterproof and other functions and can improve the mechanical properties and adsorption properties of its polyurethane coating and other substrates; the hydroxylated carbon nanotube particles and carboxylated carbon nanotube particles can give the finishing liquid heat conduction function and can improve the mechanical properties and electrical conductivity of its polyurethane coating and other substrates; the nano-silver particles and nano-basic copper sulfate particles can give the finishing liquid antibacterial function; the nano-copper sulfide particles can give the finishing liquid anti-corrosion and electrical conductivity; the nano-iron oxide particles can give the finishing liquid acid and alkali resistance and anti-ultraviolet properties.

[0016] Preferably, the dispersant is selected from one or more of sodium dodecylbenzene sulfonate, polymethacrylic acid, lauryl alcohol ether phosphate, sodium citrate, polyvinylpyrrolidone, polyacrylamide, fatty alcohol polyoxyethylene ether, and sodium ethylenediaminetetraacetate.

[0017] Preferably, the polar solvent is selected from one or more of ethanol, ethylene glycol, propylene glycol, glycerol, isopropanol and water.

[0018] Preferably, the functional finishing liquid is a dispersion of nanoparticles, the amount of the nanoparticles used is 0.2-1 wt % of the polar solvent, and the amount of the dispersant used is 0.1-0.5 wt % of the polar solvent.

[0019] After optimization, the uniformly spread waterborne polyurethane is obtained by scraping with a scraper or a wire rod, and the coating amount is 20 to 60 g / m 2 .

[0020] After optimization, the water-based polyurethane is selected from one or more of water-based polyurethane 9580C, water-based polyurethane H130D, water-based polyurethane 2019B, water-based polyurethane 209N, water-based polyurethane WPU-2426, water-based polyurethane AE-12, water-based polyurethane resin AH-1618, water-based polyurethane resin AH-1604F, water-based polyurethane resin AH-1619, water-based polyurethane resin AH-1605B, and water-based polyurethane resin AH-1739.

[0021] After optimization, the preheating treatment has a humidity of 40% to 80%, a temperature of 30 to 50° C., and a time of 10 to 20 minutes.

[0022] Preferably, the heat curing condition is baking at 60-80° C. for 20-40 minutes.

[0023] The above technical solution has the following beneficial effects:

[0024] 1. The present invention provides a method for functional finishing of polyurethane imitation leather coating durability based on nanoparticles, which can be applied to different types of nanoparticles to achieve different functionalities of the coating. The high dispersibility of functional nanoparticles can be achieved by dispersing and preparing the functional finishing liquid and spraying, thereby improving the functional finishing effect.

[0025] 2. The durable functional finishing method of the polyurethane imitation leather coating of the present invention does not require the addition of additional cross-linking agents. Through specific humidity and preheating temperature treatment, the bottom polyurethane macromolecules are driven to firmly coat the functional nanoparticles to achieve the durability of their functions. It has the advantages of simple process operation and convenient regulation. DETAILED DESCRIPTION

[0026] The invention aims to provide a method for functional finishing of polyurethane imitation leather coating durability based on nanoparticles. The principle is to ultrasonically disperse hydrophilic functional nanoparticles in a polar solvent to prepare a functional finishing liquid, then spray the functional finishing liquid onto the surface of a uniformly spread aqueous polyurethane to prepare a functional polyurethane imitation leather coating precursor, then preheat the precursor under certain humidity conditions to drive the fusion of bottom polyurethane and surface nanoparticles, and finally heat cure the precursor to drive polyurethane chain segments to approach each other to form a polyurethane film to firmly fully or semi-encapsulate the nanoparticles in the polyurethane film, thereby improving the functional durability of the polyurethane coating.

[0027] The technical solution of the present invention is further described below in conjunction with specific embodiments:

[0028] Example 1

[0029] (1) 0.06 g of nano-silica gel particles were added to an ethanol solvent containing 0.02 g of sodium citrate, and ultrasonicated for 30 min to obtain a uniformly dispersed waterproof finishing liquid, wherein the amount of ethanol used was 10 g;

[0030] (2) Use a wire rod to evenly scrape the water-based polyurethane H130D onto the release paper, with a coating amount of 30g / m 2 Then, the spray gun pressure was set to 0.4 MPa, and the prepared waterproof finishing liquid was sprayed on the evenly spread surface of the waterborne polyurethane to obtain a functional polyurethane imitation leather coating precursor;

[0031] (3) preheating the functional polyurethane imitation leather coating precursor for 10 min at a humidity of 50% and a temperature of 40° C. to drive the fusion of the bottom layer of waterborne polyurethane H130D and the surface layer of nanoparticles;

[0032] (4) baking at 60° C. for 40 min to thermally cure the preheated functional polyurethane imitation leather coating precursor, so that the polyurethane chain segments are close to each other to form a polyurethane film, which fully or half-encapsulates the nano-silica gel particles, thereby obtaining a polyurethane imitation leather coating with waterproof function and durability.

[0033] Example 2

[0034] (1) 0.02 g of nano-titanium dioxide particles and 0.06 g of nano-silver particles were added to an isopropanol solvent containing 0.04 g of polyvinylpyrrolidone, and then ultrasonicated for 60 min to obtain a uniformly dispersed antibacterial finishing liquid, wherein the amount of isopropanol used was 20 g;

[0035] (2) Use a scraper to evenly apply the water-based polyurethane AE-12 onto the release paper, with a coating amount of 40 g / m 2 Then, the spray gun pressure was set to 0.5 MPa, and the prepared antibacterial finishing liquid was sprayed on the evenly spread surface of the waterborne polyurethane to obtain a functional polyurethane imitation leather coating precursor;

[0036] (3) preheating the functional polyurethane imitation leather coating precursor for 20 minutes at a humidity of 60% and a temperature of 30° C. to drive the fusion of the bottom layer of waterborne polyurethane AE-12 and the surface layer of nanoparticles;

[0037] (4) baking at 70° C. for 30 min to thermally cure the preheated functional polyurethane imitation leather coating precursor, so that the polyurethane chain segments are close to each other to form a polyurethane film, which fully or semi-encapsulates the nano-silica gel particles, thereby obtaining a polyurethane imitation leather coating with antibacterial function and durability.

[0038] Example 3

[0039] (1) adding 0.05 g of hydroxylated carbon nanotube particles to an ethylene glycol solvent containing 0.03 g of polyacrylamide, and ultrasonicating for 20 min to obtain a uniformly dispersed conductive finishing solution, wherein the amount of ethylene glycol used is 10 g;

[0040] (2) Use a scraper to evenly apply water-based polyurethane AH-1604F onto the release paper, with a coating amount of 60g / m 2 Then, the spray gun pressure was set to 0.6 MPa, and the prepared conductive finishing liquid was sprayed on the evenly spread surface of the waterborne polyurethane to obtain a functional polyurethane imitation leather coating precursor;

[0041] (3) preheating the functional polyurethane imitation leather coating precursor for 10 min at a humidity of 60% and a temperature of 40° C. to drive the fusion of the bottom layer of waterborne polyurethane AH-1604F and the surface layer of nanoparticles;

[0042] (4) baking at 80° C. for 30 min to thermally cure the preheated functional polyurethane imitation leather coating precursor, so that the polyurethane chain segments are close to each other to form a polyurethane film, which fully or half-encapsulates the nano-silica gel particles, thereby obtaining a polyurethane imitation leather coating with conductive function and durability.

[0043] Example 4

[0044] (1) adding 0.12 g of nano zinc oxide particles to a glycerol solvent containing 0.06 g of lauryl ether phosphate, and ultrasonicating for 30 min to obtain a uniformly dispersed anti-ultraviolet finishing liquid, wherein the amount of glycerol used is 30 g;

[0045] (2) Use a wire rod to evenly scrape the water-based polyurethane AH-1619 onto the release paper, with a coating amount of 30 g / m 2 Then, the spray gun pressure was set to 0.5 MPa, and the prepared anti-ultraviolet finishing liquid was sprayed on the evenly spread surface of the waterborne polyurethane to obtain a functional polyurethane imitation leather coating precursor;

[0046] (3) preheating the functional polyurethane imitation leather coating precursor for 20 min at a humidity of 60% and a temperature of 50° C. to drive the fusion of the bottom layer waterborne polyurethane AH-1619 and the surface layer nanoparticles;

[0047] (4) baking at 80° C. for 20 min to thermally cure the preheated functional polyurethane imitation leather coating precursor, so that the polyurethane chain segments are close to each other to form a polyurethane film, which fully or semi-encapsulates the nano-silica gel particles, thereby obtaining a polyurethane imitation leather coating with UV resistance and durability.

[0048] Example 5

[0049] (1) adding 0.06 g of nano iron oxide particles to an isopropanol solvent containing 0.05 g of fatty alcohol polyoxyethylene ether, and ultrasonicating for 30 min to obtain a uniformly dispersed acid-base resistant finishing liquid, wherein the amount of isopropanol used is 20 g;

[0050] (2) Use a wire rod to evenly scrape water-based polyurethane 2019B onto the release paper, with a coating amount of 30g / m 2 Then, the spray gun pressure was set to 0.4 MPa, and the prepared acid- and alkali-resistant finishing liquid was sprayed on the evenly spread surface of the aqueous polyurethane to obtain a functional polyurethane imitation leather coating precursor;

[0051] (3) The functional polyurethane imitation leather coating precursor was preheated for 10 min at a humidity of 50% and a temperature of 60°C to drive the fusion of the bottom layer of waterborne polyurethane 2019B and the surface layer of nanoparticles;

[0052] (4) baking at 80° C. for 30 min to cure the preheated functional polyurethane imitation leather coating precursor, so that the polyurethane chain segments are close to each other to form a polyurethane film, which fully or half-encapsulates the nano-silica gel particles, thereby obtaining a polyurethane imitation leather coating with acid and alkali resistance and durability.

[0053] Example 6

[0054] (1) 0.05 g of nano basic copper sulfate particles and 0.01 g of nano silver particles were added to an ethylene glycol solvent containing 0.03 g of sodium citrate, and ultrasonicated for 30 min to obtain a uniformly dispersed waterproof finishing liquid, wherein the amount of ethylene glycol used was 10 g;

[0055] (2) Use a scraper to evenly apply water-based polyurethane WPU-2426 onto the release paper, with a coating amount of 30 g / m 2 Then, the spray gun pressure was set to 0.5 MPa, and the prepared antibacterial finishing liquid was sprayed on the evenly spread surface of the waterborne polyurethane to obtain a functional polyurethane imitation leather coating precursor;

[0056] (3) preheating the functional polyurethane imitation leather coating precursor for 10 min at a humidity of 80% and a temperature of 60° C. to drive the fusion of the bottom layer of waterborne polyurethane WPU-2426 and the surface layer of nanoparticles;

[0057] (4) baking at 70° C. for 30 min to thermally cure the preheated functional polyurethane imitation leather coating precursor, so that the polyurethane chain segments are close to each other to form a polyurethane film, which fully or semi-encapsulates the nano-silica gel particles, thereby obtaining a polyurethane imitation leather coating with antibacterial function and durability.

[0058] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements or modifications made based on the present invention to solve basically the same technical problems and achieve basically the same technical effects are all included in the protection scope of the present invention.

Claims

1. A method for improving the durability of polyurethane imitation leather coating based on nanoparticles, characterized in that The steps include: (1) Adding nanoparticles to a polar solvent containing a dispersant, and ultrasonicating for 20 to 60 minutes to obtain a functional finishing liquid; the nanoparticles are hydrophilic nanoparticles with a particle size of 8 to 100 nm; the nanoparticles are selected from one or more of nano-titanium oxide particles, nano-zinc oxide particles, nano-silica gel particles, hydroxylated carbon nanotube particles, carboxylated carbon nanotube particles, nano-silver particles, nano-basic copper sulfate particles, nano-copper sulfide particles, and nano-iron oxide particles; the dispersant is selected from one or more of sodium dodecylbenzene sulfonate, polymethacrylic acid, lauryl alcohol ether phosphate, sodium citrate, polyvinylpyrrolidone, polyacrylamide, fatty alcohol polyoxyethylene ether, and sodium ethylenediaminetetraacetate; (2) Setting the spray gun pressure to 0.3-0.6 MPa, spraying the functional finishing liquid on the surface of the spread waterborne polyurethane to obtain a functional polyurethane imitation leather coating precursor; the waterborne polyurethane is selected from one or more of waterborne polyurethane 9580C, waterborne polyurethane H130D, waterborne polyurethane 2019B, waterborne polyurethane 209N, waterborne polyurethane WPU-2426, waterborne polyurethane AE-12, waterborne polyurethane resin AH-1618, waterborne polyurethane resin AH-1604F, waterborne polyurethane resin AH-1619, waterborne polyurethane resin AH-1605B, and waterborne polyurethane resin AH-1739; (3) Under certain humidity conditions, the functional polyurethane imitation leather coating precursor is preheated to drive the fusion of the bottom polyurethane and the surface nanoparticles; the preheating humidity is 40%~80%, the temperature is 30~50℃, and the time is 10~20 min; (4) The functional polyurethane imitation leather coating precursor after preheating treatment is thermally cured, and the polyurethane chain segments are driven to approach each other by solvent evaporation, so that the polyurethane coating fully or semi-encapsulates the nanoparticles, thereby obtaining a polyurethane imitation leather coating with functional durability; the thermal curing conditions are baking at 60-80 °C for 20-40 min.

2. The method for improving the durability of polyurethane imitation leather coating based on nanoparticles according to claim 1, characterized in that: The polar solvent is selected from one or more of ethanol, ethylene glycol, propylene glycol, glycerol, isopropanol and water.

3. The method for improving the durability of polyurethane imitation leather coating based on nanoparticles according to claim 1, characterized in that: The functional finishing liquid is a dispersion of nanoparticles, the amount of the nanoparticles used is 0.2-1 wt % of the polar solvent, and the amount of the dispersant used is 0.1-0.5 wt % of the polar solvent.

4. The method for improving the durability of polyurethane imitation leather coating based on nanoparticles according to claim 1, characterized in that: The spread waterborne polyurethane coating is prepared by scraping with a scraper or a wire rod, and the coating amount is 20-60 g / m 2 .