Environment-friendly preparation method of anti-sticking sofa leather

Abstract

The invention relates to an environment-friendly preparation method of anti-sticking sofa leather, and belongs to the technical field of leather manufacturing. The environment-friendly preparation method of the anti-sticking sofa leather comprises the following steps: soaking raw cow leather in water, depilating, liming, softening, pickling, tanning, washing, oiling and drying to obtain crust leather; and coating the leather finishing agent on the surface of the crust leather, and drying to obtain the anti-sticking sofa leather. The water-based emulsion leather finishing agent is prepared through emulsion polymerization, the preparation process is environmentally friendly and small in pollution, when the water-based emulsion leather finishing agent is used for finishing crust leather, only water volatilizes in the drying process, no organic solvent or small molecule additive escapes, and no pollution is caused to the environment. The water-based emulsion leather finishing agent has relatively high hydrophobic performance, and adhesion on the surface of leather can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to an environment-friendly preparation method for anti-sticking sofa leather, belonging to the technical field of leather manufacturing. Background Art

[0002] A leather sofa is a seat made of leather processed from animal skins such as pigskin, cowhide, and sheepskin through specific processes. Since the leather made has functions such as breathability and, importantly, very good softness, using it to make a seat makes people sit very comfortably and is not easily soiled. A genuine leather sofa adds a lot of nobility and elegance to the living room. The maintenance of a genuine leather sofa is very important. If used for a long time and not properly maintained, it will fade, become old, lose its luster, and the leather will lack ductility and cause the sofa to deform. Among them, a cowhide sofa has soft, thick leather and the highest grade.

[0003] Since a sofa is a large piece of furniture and is usually used for several years, its durability has increasingly attracted the attention of consumers. During the use of a sofa, the leather fabric in contact with the outside world is often subjected to friction and scratching, especially the protruding parts at the edges of the stitches, which are prone to breakage due to friction and scratching, resulting in quality problems such as cracking and coating peeling. In addition, when the sofa leather is stacked and stored after processing, the leather surface coating is damaged due to the adhesion of the finishing layer, causing damage to the sofa leather. And currently commonly used water-based finishing agents contain a certain amount of organic solvents or small molecule volatile organic additives. During the preparation of sofa leather, these organic solvents or small molecule volatile organic additives will escape into the atmosphere, causing environmental pollution.

[0004] Therefore, there is an urgent need to develop an environment-friendly preparation method for anti-sticking sofa leather. Summary of the Invention

[0005] The purpose of the present invention is to provide an environment-friendly preparation method for anti-sticking sofa leather to solve the problem that the finishing layer of sofa leather is prone to adhesion and damage the leather surface coating during stacking and storage.

[0006] The present invention provides an environment-friendly preparation method for anti-sticking sofa leather, which comprises the following steps: soaking raw cowhide, depilating, liming, softening, pickling, and tanning to obtain semi-finished leather; then coating a leather finishing agent on the surface of the semi-finished leather and drying to obtain anti-sticking sofa leather; the preparation method of the leather finishing agent is as follows: mixing a functional monomer, methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate, dodecyl acrylate, an initiator and water to obtain emulsion A, wherein the mass of the initiator in emulsion A is 1.5-2% of the sum of the masses of the functional monomer, methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate, the mass fraction of water is 50-55%, and the mass ratio of the functional monomer, methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate is (2-4):(2-4):(5-8):(10-15):(60-65):(5-10); mixing the functional monomer, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate, dodecyl acrylate, the initiator and water to obtain emulsion B, wherein the mass of the initiator in emulsion B is 2-3% of the sum of the masses of the functional monomer, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate, the mass fraction of water is 50-55%, and the mass ratio of the functional monomer, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate is (4-6):(3-5):(8-12):(55-60):(10-15); heating emulsion A to 75-80 °C and stirring and reacting for 30-45 min to obtain a core layer emulsion, then adding emulsion B to the core layer emulsion, raising the temperature to 85-90 °C, and continuing to stir and react for 3-5 h to obtain an acrylate emulsion, wherein the mass ratio of emulsion A to emulsion B is 1:(3-4); mixing the acrylate emulsion and a nano filler with a mass ratio of 100:(3-5) to obtain the leather finishing agent, and the nano filler is selected from any two of nano silica, nano titanium dioxide, nano zinc oxide and nano bentonite; the structural formula of the functional monomer is as follows:

[0007]

[0008] In the formula, R is a C5-C7 alkyl group.

[0009] Preferably, R is a hexyl group.

[0010] Preferably, the nano filler is composed of nano silica and nano titanium dioxide, and the mass ratio of nano silica to nano titanium dioxide is (1-2):(2-3).

[0011] Preferably, the average particle size of the nano silica is 5-10 nm.

[0012] Preferably, the average particle size of the nano titanium dioxide is 15-20 nm.

[0013] Preferably, for the drying, the leather blank coated with the leather finishing agent is first dried at 100 - 110°C for 1 - 1.5 min, and then dried at 60 - 70°C for 1 - 1.5 h.

[0014] Preferably, the coating amount of the leather finishing agent is 20 - 25 g / m 2 .

[0015] Preferably, the preparation method of the functional monomer is as follows:

[0016] (1) Mix and react a thiosulfate alcohol compound and 2,2,3,3,4,4 - hexafluoroglutaric anhydride to obtain a thiofluoric acid ester; the molar ratio of the thiosulfate alcohol compound to 2,2,3,3,4,4 - hexafluoroglutaric anhydride is 1:1; the structural formula of the thiosulfate alcohol compound is as follows:

[0017]

[0018] (2) Mix and react the thiofluoric acid ester and a monochloro - hydrocarbon at 95 - 100°C to obtain a thiofluoric acid ester quaternary ammonium salt; the molar ratio of the thiofluoric acid ester to the monochloro - hydrocarbon is 1:1.02 - 1.05;

[0019] (3) Mix and react the thiofluoric acid ester quaternary ammonium salt and glycidyl methacrylate under the catalysis of tetrabutylammonium bromide at 90 - 95°C to obtain a thiofluoric acid ester quaternary ammonium salt monomer; the molar ratio of the thiofluoric acid ester quaternary ammonium salt to glycidyl methacrylate is 1:1;

[0020] (4) Mix and react the thiofluoric acid ester quaternary ammonium salt monomer and 1 - chloroformyl - 2 - imidazolidinone at 0 - 5°C to obtain the functional monomer.

[0021] Preferably, in step (1), the temperature of the mixing reaction is 80 - 100°C and the time is 4 - 6 h; in step (2), the time of the mixing reaction is 8 - 12 h, and the monochloro - hydrocarbon is one of 1 - chlorohexane, 1 - chloropentane, and 1 - chlorooctane; in step (3), the time of the mixing reaction is 3 - 4 h, and the mass of tetrabutylammonium bromide is 0.8 - 1% of the sum of the masses of the thiofluoric acid ester quaternary ammonium salt and glycidyl methacrylate; in step (5), the time of the mixing reaction is 5 - 6 h.

[0022] Preferably, the preparation method of the thiosulfate alcohol compound is as follows: Add 3 mol of diethylamine, 3 mol of mercaptoethanol, and 3.5 - 4 L of anhydrous dichloromethane into a reaction kettle, stir evenly, then cool the materials in the reaction kettle to 0 - 2 °C, and then dropwise add 3 mol of carbon disulfide into the reaction kettle. Then slowly add 3.2 - 3.5 mol of triethylamine. After 5 - 8 min, add an anhydrous dichloromethane solution containing 3 mol of carbon tetrabromide, and stir and react at room temperature for 4 - 6 h. After the reaction is completed, purify to obtain the thiosulfate alcohol compound.

[0023] The beneficial effects of the present invention are as follows:

[0024] (1) The present invention first prepares an aqueous emulsion leather finishing agent by emulsion polymerization. The preparation process has little environmental pollution. When the aqueous emulsion leather finishing agent is applied to the leather blank, only water volatilizes during the drying process, and no organic solvents and small molecule additives escape, which has no pollution to the environment. The aqueous emulsion leather finishing agent has strong hydrophobic properties and can effectively reduce the adhesion on the leather surface.

[0025] (2) The present invention synthesizes a functional monomer with a unique molecular composition and structure. The quaternary ammonium salt group, thionylcarbonyl group, disulfide segment, and fluorinated carbon chain in the functional monomer have dual hydrophilic and lipophilic properties, and have a relatively long molecular chain, which can diffuse far away in the emulsion and the coating to exert dual hydrophilic and lipophilic properties. Moreover, the imidazolidinone group with a shorter molecular chain also has weak dual hydrophilic and lipophilic properties, which can form a stepped structure with the quaternary ammonium salt group, thionylcarbonyl group, disulfide segment, and fluorinated carbon chain to exert double-layer dual hydrophilic and lipophilic properties, thereby improving the wetting and dispersion stability of nano-silica and nano-titanium dioxide and the wear resistance, water permeability, and folding resistance of the coating.

[0026] (3) The present invention screens nano-fillers compatible with the acrylate emulsion, which can avoid the problem that the poor affinity between the nano-fillers and the acrylate emulsion leads to easy agglomeration during coating, blocking the leather pores, and reducing the water permeability of the leather. In addition, the present invention adjusts the particle sizes of nano-silica and nano-titanium dioxide, and uses nano-silica and nano-titanium dioxide with different particle sizes to form a stronger rough structure, improving the wear resistance, folding resistance, and water permeability of the finishing layer.

[0027] (4) The present invention adjusts the hydrophilicity-hydrophobicity of the quaternary ammonium salt carbon chain and the ionic radius of the anion in the acrylate emulsion, improving the wetting and dispersion stability of the acrylate emulsion to nano-silica and nano-titanium dioxide and the degree of stretching of the acrylate molecular chain, thereby improving the comprehensive performance of the anti-sticking sofa leather.

[0028] (5) Through the two-stage heating and drying process of the present invention, the stable dispersion and embedding of nano-silica and nano-titanium dioxide in the emulsion are improved, forming a uniform and stable coating system, and improving the comprehensive performance of the coating layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the nuclear magnetic hydrogen spectrum of the functional monomer prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] The following examples are intended to further illustrate the content of the present invention rather than limit the protection scope of the present invention.

[0031] Example 1

[0032] The environment-friendly preparation method of the anti-sticking sofa leather in this example includes the following steps:

[0033] (1) Add 3 mol of diethylamine, 3 mol of mercaptoethanol and 3.5 L of anhydrous dichloromethane into the reaction kettle, stir evenly, then cool the materials in the reaction kettle to 0 °C, then dropwise add 3 mol of carbon disulfide into the reaction kettle, and then slowly add 3.2 mol of triethylamine. After 5 min, add the anhydrous dichloromethane solution of carbon tetrabromide (the mass fraction of the anhydrous dichloromethane solution of carbon tetrabromide is 10%, containing 3 mol of carbon tetrabromide), stir and react at room temperature for 4 h. After the reaction is completed, add water for extraction, distill the organic phase under reduced pressure to remove the organic solvent, obtain the crude product, and then carry out column chromatography purification using petroleum ether / ethyl acetate as the eluent, and distill the purified and collected liquid under reduced pressure to remove the solvent to obtain the thiosulfate alcohol compound.

[0034] (2) Add the thiosulfate alcohol compound and ether into the reaction kettle, stir evenly to obtain a solution with a mass fraction of 40%, then add 2,2,3,3,4,4-hexafluoroglutaric anhydride (the molar ratio of the thiosulfate alcohol compound to 2,2,3,3,4,4-hexafluoroglutaric anhydride is 1:1), heat to 80 °C, stir and reflux for 4 h, distill the materials in the reaction kettle under reduced pressure to remove the solvent ether to obtain the thiosulfate fluoride.

[0035] (3) Add the thiosulfate fluoride and ether into the reaction kettle, stir evenly to obtain a solution with a mass fraction of 20%, then add sodium carbonate to adjust the pH of the solution to 10, heat to 95 °C, and then dropwise add 1-chlorohexane (the molar ratio of the thiosulfate fluoride to 1-chlorohexane is 1:1.02). After the dropping is completed, continue to stir and reflux for 8 h. Extract the reaction product with water to remove sodium carbonate, and then distill the organic phase under reduced pressure to remove the solvent to obtain the thiosulfate fluoride quaternary ammonium salt.

[0036] (4) Add thiofluoroate quaternary ammonium salt, glycidyl methacrylate, and ethyl ether into a reaction kettle, and then add the catalyst tetrabutylammonium bromide. The mass ratio of thiofluoroate quaternary ammonium salt to ethyl ether is 25:100, the molar ratio of thiofluoroate quaternary ammonium salt to glycidyl methacrylate is 1:1, and the mass of the catalyst tetrabutylammonium bromide is 0.8% of the sum of the masses of thiofluoroate quaternary ammonium salt and glycidyl methacrylate. Then heat the materials in the reaction kettle to 90 °C, stir and reflux for 3 h. After cooling to room temperature, carry out rotary evaporation under reduced pressure on the reaction product to obtain the thiofluoroate quaternary ammonium salt monomer.

[0037] (5) Add the thiofluoroate quaternary ammonium salt monomer and anhydrous acetone into a reaction kettle to obtain a thiofluoroate quaternary ammonium salt monomer solution with a mass fraction of 25%. Then cool the materials in the reaction kettle to 0 °C, dropwise add an acetone solution of 1-chloroformyl-2-imidazolidinone (mass fraction is 30%, and the molar ratio of 1-chloroformyl-2-imidazolidinone to the hydroxyl group in the thiofluoroate quaternary ammonium salt monomer is 1:1) into the reaction kettle, add an appropriate amount of triethylamine as an acid-binding agent, and then stir and react the materials in the reaction kettle at 5 °C for 5 h. Filter, and carry out rotary evaporation under reduced pressure on the filtrate to obtain the functional monomer, and the structural formula is as follows:

[0038] R is hexyl.

[0039] Carry out nuclear magnetic resonance hydrogen spectrum test on the prepared functional monomer, and the results are as Figure 1 shown.

[0040] (6) Add the functional monomer, methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate, dodecyl acrylate, initiator ammonium persulfate, and water into a stirring kettle, stir evenly to obtain emulsion A. In emulsion A, the mass of the initiator ammonium persulfate is 1.5% of the sum of the masses of the functional monomer, methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate, and dodecyl acrylate, the mass fraction of water is 50%, and the mass ratio of the functional monomer, methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate, and dodecyl acrylate is 2:2:5:10:60:5.

[0041] Add the functional monomer, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate, dodecyl acrylate, initiator ammonium persulfate, and water into a stirring kettle, stir evenly to obtain emulsion B. In emulsion B, the mass of the initiator ammonium persulfate is 2% of the sum of the masses of the functional monomer, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate, and dodecyl acrylate, the mass fraction of water is 50%, and the mass ratio of the functional monomer, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate, and dodecyl acrylate is 4:3:8:55:10.

[0042] Heat emulsion A to 75 °C and stir for 30 min to obtain the core layer emulsion. Then add emulsion B to the core layer emulsion, raise the temperature to 85 °C, and continue stirring for 3 h to obtain the acrylate emulsion. The mass ratio of emulsion A to emulsion B is 1:3.

[0043] (7) Add the acrylate emulsion, nano-silica, and nano-titanium dioxide to a stirring kettle and stir evenly to obtain the leather finishing agent. Among them, the mass ratio of the acrylate emulsion, nano-silica, and nano-titanium dioxide is 100:1:2. The average particle size of nano-silica is 5 nm, and the average particle size of nano-titanium dioxide is 15 nm.

[0044] (8) Immerse raw cowhide in water, remove hair, soak in lime, soften, soak in acid, tan, wash with water, add oil, and dry to obtain the semi-finished leather. Roll the leather finishing agent prepared in step (7) onto the surface of the semi-finished leather using a roller coater. The coating amount of the leather finishing agent is 20 g / m 2 , dry the semi-finished leather coated with the leather finishing agent at 100 °C for 1 min first, and then dry it at 60 °C for 1 h to obtain the anti-stick sofa leather.

[0045] Example 2

[0046] The environmentally friendly preparation method of the anti-stick sofa leather in this example includes the following steps:

[0047] (1) Add 3 mol of diethylamine, 3 mol of mercaptoethanol, and 4 L of anhydrous dichloromethane to a reaction kettle and stir evenly. Then cool the materials in the reaction kettle to 2 °C, and then drop 3 mol of carbon disulfide into the reaction kettle. Then slowly add 3.5 mol of triethylamine. After 8 min, add the anhydrous dichloromethane solution of carbon tetrabromide (the mass fraction of the anhydrous dichloromethane solution of carbon tetrabromide is 10%, containing 3 mol of carbon tetrabromide), and stir at room temperature for 6 h. After the reaction is completed, add water for extraction, distill the organic phase under reduced pressure to remove the organic solvent, obtain the crude product, and then carry out column chromatography purification using petroleum ether / ethyl acetate as the eluent. Distill the purified and collected liquid under reduced pressure to remove the solvent to obtain the thiosulfate alcohol compound.

[0048] (2) Add the thiosulfate alcohol compound and ether to a reaction kettle and stir evenly to obtain a solution with a mass fraction of 45%. Then add 2,2,3,3,4,4-hexafluoroglutaric anhydride (the molar ratio of the thiosulfate alcohol compound to 2,2,3,3,4,4-hexafluoroglutaric anhydride is 1:1), heat to 100 °C, and stir and reflux for 6 h. Distill the materials in the reaction kettle under reduced pressure to remove the solvent ether to obtain the thiofluoroester.

[0049] (3) Add thiofluoric acid ester and ethyl ether into a reaction kettle, stir evenly to obtain a solution with a mass fraction of 25%, then add sodium carbonate, adjust the pH of the solution to 10, heat it to 100 °C, and then dropwise add 1-chlorohexane (the molar ratio of thiofluoric acid ester to 1-chlorohexane is 1:1.05). After the dropping is completed, continue to stir and reflux for 12 h. Extract the reaction product with water to remove sodium carbonate, and then distill the organic phase under reduced pressure to remove the solvent to obtain thiofluoric acid ester quaternary ammonium salt.

[0050] (4) Add thiofluoric acid ester quaternary ammonium salt, glycidyl methacrylate and ethyl ether into a reaction kettle, and then add the catalyst tetrabutylammonium bromide. The mass ratio of thiofluoric acid ester quaternary ammonium salt to ethyl ether is 30:100, the molar ratio of thiofluoric acid ester quaternary ammonium salt to glycidyl methacrylate is 1:1, and the mass of the catalyst tetrabutylammonium bromide is 1% of the sum of the masses of thiofluoric acid ester quaternary ammonium salt and glycidyl methacrylate. Then heat the materials in the reaction kettle to 95 °C, stir and reflux for 4 h. After cooling to room temperature, carry out rotary evaporation under reduced pressure on the reaction product to obtain thiofluoric acid ester quaternary ammonium salt monomer.

[0051] (5) Add thiofluoric acid ester quaternary ammonium salt monomer and anhydrous acetone into a reaction kettle to obtain a thiofluoric acid ester quaternary ammonium salt monomer solution with a mass fraction of 25%. Then cool the materials in the reaction kettle to 5 °C, dropwise add an acetone solution of 1-chloroformyl-2-imidazolidinone (mass fraction 30%, the molar ratio of 1-chloroformyl-2-imidazolidinone to the hydroxyl group in thiofluoric acid ester quaternary ammonium salt monomer is 1:1), add an appropriate amount of triethylamine as an acid-binding agent, and then stir the materials in the reaction kettle at 8 °C for 6 h. Filter, and carry out rotary evaporation under reduced pressure on the filtrate to obtain a functional monomer, and the structural formula is as follows:

[0052] R is hexyl.

[0053] (6) Add the functional monomer, methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate, dodecyl acrylate, initiator ammonium persulfate and water into a stirring kettle, stir evenly to obtain emulsion A. The mass of initiator ammonium persulfate in emulsion A is 2% of the sum of the masses of the functional monomer, methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate, the mass fraction of water is 55%, and the mass ratio of the functional monomer, methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate is 4:4:8:15:65:10.

[0054] The functional monomer, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate, dodecyl acrylate, ammonium persulfate as the initiator and water are added into a stirring kettle, stirred evenly to obtain Emulsion B. In Emulsion B, the mass of ammonium persulfate as the initiator is 3% of the sum of the masses of the functional monomer, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate, the mass fraction of water is 55%, and the mass ratio of the functional monomer, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate is 6:5:12:60:15.

[0055] Emulsion A is heated to 80 °C and stirred for reaction for 45 min to obtain the core layer emulsion. Then, Emulsion B is added into the core layer emulsion, the temperature is raised to 90 °C, and stirring reaction is continued for 5 h to obtain the acrylate emulsion; the mass ratio of Emulsion A and Emulsion B is 1:4.

[0056] (7) The acrylate emulsion, nano-silica and nano-titanium dioxide are added into a stirring kettle, stirred evenly to obtain the leather finishing agent; wherein, the mass ratio of the acrylate emulsion, nano-silica and nano-titanium dioxide is 100:2:3, the average particle size of nano-silica is 10 nm, and the average particle size of nano-titanium dioxide is 20 nm.

[0057] (8) The raw cowhide is soaked, dehaired, limed, softened, pickled, tanned, washed, oiled and dried to obtain the semi-finished leather; the leather finishing agent prepared in step (7) is roll-coated onto the surface of the semi-finished leather by a roll coater, and the coating amount of the leather finishing agent is 25 g / m 2 , and the semi-finished leather coated with the leather finishing agent is first dried at 110 °C for 1.5 min, and then dried at 70 °C for 1.5 h to obtain the anti-sticking sofa leather.

[0058] Example 3

[0059] The environmental protection preparation method of the anti-sticking sofa leather in this example includes the following steps:

[0060] (1) 3 mol of diethylamine, 3 mol of mercaptoethanol and 3.7 L of anhydrous dichloromethane are added into a reaction kettle, stirred evenly, then the materials in the reaction kettle are cooled to 0-2 °C, 3 mol of carbon disulfide is added dropwise into the reaction kettle, and then 3.3 mol of triethylamine is slowly added. After 5-8 min, an anhydrous dichloromethane solution of carbon tetrabromide (the mass fraction of the anhydrous dichloromethane solution of carbon tetrabromide is 10% and contains 3 mol of carbon tetrabromide) is added, and stirring reaction is carried out at room temperature for 5 h. After the reaction is completed, water is added for extraction, the organic phase is distilled under reduced pressure to remove the organic solvent to obtain the crude product, and then column chromatography purification is carried out using petroleum ether / ethyl acetate as the eluent, and the purified and collected liquid is distilled under reduced pressure to remove the solvent to obtain the thiosulfate alcohol compound.

[0061] (2) Add the thiosulfate alcohol compound and ethyl ether into a reaction kettle, stir evenly to obtain a solution with a mass fraction of 42%, then add 2,2,3,3,4,4-hexafluoroglutaric anhydride (the molar ratio of the thiosulfate alcohol compound to 2,2,3,3,4,4-hexafluoroglutaric anhydride is 1:1), heat to 90 °C, stir and reflux for 5 h, and subject the materials in the reaction kettle to vacuum distillation to remove the solvent ethyl ether to obtain thiofluoric acid ester.

[0062] (3) Add the thiofluoric acid ester and ethyl ether into a reaction kettle, stir evenly to obtain a solution with a mass fraction of 22%, then add sodium carbonate to adjust the pH of the solution to 10, raise the temperature to 98 °C, and then dropwise add 1-chlorohexane (the molar ratio of the thiofluoric acid ester to 1-chlorohexane is 1:1.03). After the dropping is completed, continue to stir and reflux for 10 h. Extract the reaction product with water to remove sodium carbonate, and then subject the organic phase to vacuum distillation to remove the solvent to obtain thiofluoric acid ester quaternary ammonium salt.

[0063] (4) Add the thiofluoric acid ester quaternary ammonium salt, glycidyl methacrylate and ethyl ether into a reaction kettle, and then add the catalyst tetrabutylammonium bromide. The mass ratio of the thiofluoric acid ester quaternary ammonium salt to ethyl ether is 28:100, the molar ratio of the thiofluoric acid ester quaternary ammonium salt to glycidyl methacrylate is 1:1, and the mass of the catalyst tetrabutylammonium bromide is 0.9% of the sum of the masses of the thiofluoric acid ester quaternary ammonium salt and glycidyl methacrylate. Then heat the materials in the reaction kettle to 92 °C, stir and reflux for 3.5 h. After cooling to room temperature, subject the reaction product to vacuum rotary evaporation to obtain thiofluoric acid ester quaternary ammonium salt monomer.

[0064] (5) Add the thiofluoric acid ester quaternary ammonium salt monomer and anhydrous acetone into a reaction kettle to obtain a thiofluoric acid ester quaternary ammonium salt monomer solution with a mass fraction of 25%. Then cool the materials in the reaction kettle to 2 °C, dropwise add an acetone solution of 1-chloroformyl-2-imidazolidinone (mass fraction 30%, the molar ratio of 1-chloroformyl-2-imidazolidinone to the hydroxyl group in the thiofluoric acid ester quaternary ammonium salt monomer is 1:1), add an appropriate amount of triethylamine as an acid-binding agent, and then stir the materials in the reaction kettle at 6 °C for 5.5 h, filter, and subject the filtrate to vacuum rotary evaporation to obtain a functional monomer, and the structural formula is as follows:

[0065] R is hexyl.

[0066] (6) Add the functional monomer, methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate, dodecyl acrylate, ammonium persulfate initiator and water into a stirring kettle, stir evenly to obtain Emulsion A. In Emulsion A, the mass of ammonium persulfate initiator is 1.8% of the sum of the masses of the functional monomer, methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate. The mass fraction of water is 52%. The mass ratio of the functional monomer, methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate is 3:3:7:12:63:6.

[0067] Add the functional monomer, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate, dodecyl acrylate, ammonium persulfate initiator and water into a stirring kettle, stir evenly to obtain Emulsion B. In Emulsion B, the mass of ammonium persulfate initiator is 2.5% of the sum of the masses of the functional monomer, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate. The mass fraction of water is 52%. The mass ratio of the functional monomer, 2-hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate is 5:4:10:57:13.

[0068] Heat Emulsion A to 78 °C and stir and react for 40 min to obtain the core layer emulsion. Then add Emulsion B to the core layer emulsion, raise the temperature to 88 °C and continue to stir and react for 4 h to obtain the acrylate emulsion. The mass ratio of Emulsion A to Emulsion B is 1:3.5.

[0069] (7) Add the acrylate emulsion, nano-silica and nano-titanium dioxide into a stirring kettle, stir evenly to obtain the leather finishing agent. Among them, the mass ratio of the acrylate emulsion, nano-silica and nano-titanium dioxide is 100:1.5:2.5. The average particle size of nano-silica is 8 nm, and the average particle size of nano-titanium dioxide is 17 nm.

[0070] (8) Soak raw cowhide in water, remove hair, soak in lime, soften, soak in acid, tan, wash with water, add oil and dry to obtain the semi-finished leather. Roll the leather finishing agent prepared in step (7) onto the surface of the semi-finished leather with a roller coater. The coating amount of the leather finishing agent is 23 g / m 2 , and first dry the semi-finished leather coated with the leather finishing agent at 105 °C for 1.2 min, and then dry it at 65 °C for 1.3 h to obtain the anti-stick sofa leather.

[0071] Example 4

[0072] The difference between the environmentally friendly preparation method of the anti-stick sofa leather in this example and the environmentally friendly preparation method of the anti-stick sofa leather in Example 1 is only that in step (7) of the environmentally friendly preparation method of the anti-stick sofa leather in this example, nano-titanium dioxide is replaced with nano-zinc oxide of the same particle size.

[0073] Example 5

[0074] The difference between the environment-friendly preparation method of the anti-sticking sofa leather in this example and that in Example 1 is only that in step (7) of the environment-friendly preparation method of the anti-sticking sofa leather in this example, nano-silica is replaced by nano-bentonite with the same particle size.

[0075] Example 6

[0076] The difference between the environment-friendly preparation method of the anti-sticking sofa leather in this example and that in Example 1 is only that in step (3) of the environment-friendly preparation method of the anti-sticking sofa leather in this example, 1-chlorohexane is replaced by 1-chloropentane.

[0077] Example 7

[0078] The difference between the environment-friendly preparation method of the anti-sticking sofa leather in this example and that in Example 1 is only that in step (3) of the environment-friendly preparation method of the anti-sticking sofa leather in this example, 1-chlorohexane is replaced by 1-chlorooctane.

[0079] Example 8

[0080] The difference between the environment-friendly preparation method of the anti-sticking sofa leather in this example and that in Example 1 is only that in step (3) of the environment-friendly preparation method of the anti-sticking sofa leather in this example, 1-chlorohexane is replaced by 1-bromohexane.

[0081] Example 9

[0082] The difference between the environment-friendly preparation method of the anti-sticking sofa leather in this example and that in Example 1 is only that in step (6) of the environment-friendly preparation method of the anti-sticking sofa leather in this example, the functional monomer is replaced by a thiofluoroate quaternary ammonium salt monomer.

[0083] Example 10

[0084] The difference between the environment-friendly preparation method of the anti-sticking sofa leather in this example and that in Example 1 is only that in step (7) of the environment-friendly preparation method of the anti-sticking sofa leather in this example, the average particle size of nano-silica is adjusted from 5 nm to 15 nm.

[0085] Example 11

[0086] The difference between the environment-friendly preparation method of the anti-sticking sofa leather in this example and that in Example 1 is only that in step (7) of the environment-friendly preparation method of the anti-sticking sofa leather in this example, the average particle size of nano-silica is adjusted from 5 nm to 2 nm.

[0087] Example 12

[0088] The difference between the environment-friendly preparation method of the anti-sticking sofa leather in this example and the environment-friendly preparation method of the anti-sticking sofa leather in Example 1 is only that in step (7) of the environment-friendly preparation method of the anti-sticking sofa leather in this example, the average particle size of the nano-titanium dioxide is adjusted from 15 nm to 5 nm.

[0089] Example 13

[0090] The difference between the environment-friendly preparation method of the anti-sticking sofa leather in this example and the environment-friendly preparation method of the anti-sticking sofa leather in Example 1 is only that in step (7) of the environment-friendly preparation method of the anti-sticking sofa leather in this example, the average particle size of the nano-titanium dioxide is adjusted from 15 nm to 25 nm.

[0091] Example 14

[0092] The difference between the environment-friendly preparation method of the anti-sticking sofa leather in this example and the environment-friendly preparation method of the anti-sticking sofa leather in Example 1 is only that in step (8) of the environment-friendly preparation method of the anti-sticking sofa leather in this example, the leather blank coated with the leather finishing agent is dried at 100 °C for 30 min to obtain the anti-sticking sofa leather.

[0093] Example 15

[0094] The difference between the environment-friendly preparation method of the anti-sticking sofa leather in this example and the environment-friendly preparation method of the anti-sticking sofa leather in Example 1 is only that in step (8) of the environment-friendly preparation method of the anti-sticking sofa leather in this example, the leather blank coated with the leather finishing agent is dried at 60 °C for 2 h to obtain the anti-sticking sofa leather.

[0095] Effect Example

[0096] In order to investigate the comprehensive performance of the anti - sticking sofa leather prepared in each example, the anti - sticking performance, water vapor permeability performance, wear resistance performance and folding resistance performance of the anti - sticking sofa leather were tested. Among them, the anti - sticking performance was evaluated by contact angle, tape adhesion and anti - sticking test; during the evaluation, a contact angle measuring instrument was used to measure the contact angle r between the leather finishing layer on the leather surface and water; the anti - sticking sofa leather was placed flat on the test bench, and then a polyurethane tape with a certain width and length was pasted on the leather finishing layer of the anti - sticking sofa leather, and a 1 kg heavy object was pressed for 24 h, and then the tape was pulled with a tensiometer to measure the adhesion force F between the tape and the leather finishing layer; the anti - sticking test was to stack multiple layers of leather under the same conditions, and then test and record the longest stacking storage time when the finishing layer adhered and damaged the leather surface coating, that is, the leather surface adhesion time T; according to the method specified in the standard QBT 1811 - 1993 "Test Method for Water Vapor Permeability of Leather", the water vapor permeability P of the semi - finished leather and the prepared anti - sticking sofa leather in each example was tested; according to the method specified in the standard SATRA TM 163 "Taber Abrasion Test", the wear resistance of the leather finishing layer of the anti - sticking sofa leather prepared in each example was tested, and the experimental result was expressed by the mass loss M0 of the specimen; according to the method specified in the standard QBT 2714 - 2005 "Determination of Folding Fastness of Leather - Physical and Mechanical Tests", the folding fastness of the anti - sticking sofa leather prepared in each example was tested. During the test, a folding resistance testing machine was used, and the test mode was dry - state test. The experimental result was expressed by the maximum number of folding resistance times N when the leather finishing layer of the folded part on the leather surface did not show damage. The comprehensive performance of the anti - sticking sofa leather prepared in each example is shown in Table 1.

[0097] Table 1 Comprehensive Performance of Anti - sticking Sofa Leather Prepared in Each Example

[0098]

[0099] As can be seen from Table 1, the anti - sticking sofa leather prepared in Examples 1 - 3 shows strong hydrophobic properties, has a low adhesion force to polyurethane tape, has little influence on the water vapor permeability of the leather, and has good wear resistance and folding resistance performance, and the number of folding resistance times is greater than 200,000 times.

[0100] Compared with Example 1, after replacing nano-titanium dioxide with nano-zinc oxide or replacing nano-silica with nano-bentonite, the hydrophobic property of the anti-sticking sofa leather slightly decreases, and the adhesion to the polyurethane tape increases. This indicates that the anti-sticking effect of the finishing agent prepared with nano-zinc oxide or nano-bentonite is slightly worse. Moreover, the water vapor permeability of the anti-sticking sofa leather prepared in Examples 4 - 5 decreases significantly compared to the leather blank, suggesting that nano-zinc oxide or nano-bentonite has a greater impact on the water vapor permeability of the leather and is not conducive to maintaining the water vapor permeability of the leather. This may be because the affinity between nano-zinc oxide or nano-bentonite and the acrylate emulsion is poor, and they are prone to agglomeration during coating, blocking the pores of the leather and resulting in a decrease in water vapor permeability. Additionally, the abrasion resistance and folding resistance of the anti-sticking sofa leather prepared in Examples 4 - 5 also deteriorate, which may also be related to the poor affinity between nano-zinc oxide or nano-bentonite and the acrylate emulsion.

[0101] Compared with Example 1, when changing the quaternary ammonium salt carbon chain length or the anion type in the thiofluoroate quaternary ammonium salt monomer, the contact angle of the anti-sticking sofa leather with water and the adhesion to the polyurethane tape increase, and the abrasion resistance and folding resistance deteriorate. Moreover, the water vapor permeability of the leather blank becomes worse. This may be because the hydrophilic-hydrophobic property of the quaternary ammonium salt carbon chain in the acrylate emulsion and the relatively large ionic radius of the bromide ion lead to poor wetting and dispersion stability of the acrylate emulsion with nano-silica and nano-titanium dioxide, as well as poor stretching degree of the acrylate molecular chain.

[0102] Compared with Example 1, when replacing the functional monomer with the thiofluoroate quaternary ammonium salt monomer, the comprehensive performance of the prepared anti-sticking sofa leather is poor and cannot meet the usage requirements. This indicates that using the functional monomer can effectively improve the comprehensive performance of the anti-sticking sofa leather. This is because of the unique molecular composition and structure of the functional monomer. The quaternary ammonium salt group, thioxocarbonyl group, disulfide segment, and fluorinated carbon chain in it have dual hydrophilic and lipophilic properties, and have a relatively long molecular chain, which can diffuse far away in the emulsion and coating, exerting dual hydrophilic and lipophilic properties. Moreover, the imidazolidinone group with a shorter molecular chain also has weak dual hydrophilic and lipophilic properties, which can form a stepped structure with the quaternary ammonium salt group, thioxocarbonyl group, disulfide segment, and fluorinated carbon chain, exerting double-layer dual hydrophilic and lipophilic properties, thereby improving the wetting and dispersion stability with nano-silica and nano-titanium dioxide, as well as the abrasion resistance, water vapor permeability, and folding resistance of the coating.

[0103] Compared with Example 1, after adjusting the particle sizes of nano-silica and nano-titanium dioxide, the comprehensive performance of the anti-sticking sofa leather also deteriorates. This may be because nano-silica and nano-titanium dioxide with different particle sizes can form a stronger rough structure, improving the abrasion resistance, folding resistance, and water vapor permeability of the finishing layer. However, after changing the particle sizes, the dispersion arrangement of nano-silica and nano-titanium dioxide in the emulsion and the formed rough structure change, resulting in a deterioration of the comprehensive performance.

[0104] Compared with Example 1, when one-stage heating and drying is adopted, the comprehensive performance of the anti-stick sofa leather prepared is also slightly worse. This may be because the two-stage heating and drying process is conducive to the stable dispersion and embedding of nano-silica and nano-titanium dioxide in the emulsion, forming a uniform and stable coating system and improving the comprehensive performance of the finishing layer.

Claims

1. An environmentally friendly preparation method for anti-stick sofa leather, characterized in that: The following steps are involved: The raw cowhide is soaked in water, dehaired, limed, softened, pickled and tanned to obtain crust leather; a leather finishing agent is then applied to the surface of the crust leather, and anti-stick sofa leather is obtained after drying; the preparation method of the leather finishing agent is as follows: functional monomers, methacrylic acid, hydroxyethyl methacrylate, acrylamide, butyl acrylate, dodecyl acrylate, an initiator and water are mixed to obtain emulsion A, the mass of the initiator in emulsion A is 1.5-2% of the sum of the mass of the functional monomers, methacrylic acid, hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate, the mass fraction of water is 50-55%, and the mass ratio of the functional monomers, methacrylic acid, hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate is (2-4):(2-4):(5-8):(10-15):(60-65):(5-10); the functional monomers, hydroxyethyl methacrylate, acrylamide, butyl acrylate, dodecyl acrylate, an initiator and water are mixed to obtain an emulsion A; Emulsion B, the mass of the initiator in emulsion B is 2-3% of the sum of the mass of the functional monomer, hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate, the mass fraction of water is 50-55%, and the mass ratio of the functional monomer, hydroxyethyl methacrylate, acrylamide, butyl acrylate and dodecyl acrylate is (4-6):(3-5):(8-12):(55-60):(10-15); Emulsion A is heated to 75-80°C and stirred for 30-45 min to obtain a core layer emulsion, then add emulsion B to the core layer emulsion, raise the temperature to 85-90° C., continue stirring and reacting for 3-5 hours to obtain an acrylate emulsion, wherein the mass ratio of emulsion A to emulsion B is 1:(3-4); the acrylate emulsion and the nanofiller at a mass ratio of 100:(3-5) are mixed to obtain a leather finishing agent, wherein the nanofiller is selected from any two of nano silicon dioxide, nano titanium dioxide, nano zinc oxide and nano bentonite; the structural formula of the functional monomer is as follows: In the formula, R is a C5-C7 alkyl group.

2. The environmentally friendly preparation method of the anti-stick sofa leather according to claim 1, characterized in that: The R is a hexyl group.

3. The environmentally friendly preparation method of the anti-stick sofa leather according to claim 1, characterized in that: The nano filler consists of nano silicon dioxide and nano titanium dioxide, and the mass ratio of the nano silicon dioxide to the nano titanium dioxide is (1-2):(2-3).

4. The environmentally friendly preparation method of the anti-stick sofa leather according to claim 3, characterized in that: The average particle size of the nano silicon dioxide is 5 to 10 nm.

5. The environmentally friendly preparation method of the anti-stick sofa leather according to claim 3, characterized in that: The average particle size of the nano titanium dioxide is 15 to 20 nm.

6. The environmentally friendly preparation method of the anti-stick sofa leather according to claim 1, characterized in that: The drying process comprises first drying the crust leather coated with the leather finishing agent at 100-110° C. for 1-1.5 minutes, and then drying it at 60-70° C. for 1-1.5 hours.

7. The environmentally friendly preparation method of the anti-stick sofa leather according to claim 1 or 6, characterized in that: The coating amount of leather finishing agent is 20-25g / m 2 .

8. The environmentally friendly preparation method of the anti-stick sofa leather according to claim 1, characterized in that: The preparation method of the functional monomer is as follows: (1) mixing a thiosulfate alcohol compound and 2,2,3,3,4,4-hexafluoroglutaric anhydride to react to obtain a thiofluoride ester; the molar ratio of the thiosulfate alcohol compound to the 2,2,3,3,4,4-hexafluoroglutaric anhydride is 1:1; the structural formula of the thiosulfate alcohol compound is as follows: (2) mixing a thiofluoric acid ester and a monochlorohydrocarbon at 95 to 100° C. to obtain a quaternary ammonium thiofluoric acid ester; the molar ratio of the thiofluoric acid ester to the monochlorohydrocarbon is 1:1.02 to 1.05; (3) mixing thiofluoride ester quaternary ammonium salt and glycidyl methacrylate at 90-95° C. under the catalytic action of tetrabutylammonium bromide to obtain thiofluoride ester quaternary ammonium salt monomer; the molar ratio of thiofluoride ester quaternary ammonium salt to glycidyl methacrylate is 1:1; (4) Mixing the thiofluoride ester quaternary ammonium salt monomer and 1-chloroformyl-2-imidazolidinone at 0-5° C. to react, thereby obtaining a functional monomer.

9. The environmentally friendly preparation method of the anti-stick sofa leather according to claim 8, characterized in that: The temperature of the mixed reaction in step (1) is 80-100° C. and the time is 4-6 hours; the time of the mixed reaction in step (2) is 8-12 hours, and the monochlorohydrocarbon is one of 1-chlorohexane, 1-chloropentane and 1-chlorooctane; the time of the mixed reaction in step (3) is 3-4 hours, and the mass of tetrabutylammonium bromide is 0.8-1% of the sum of the mass of quaternary ammonium thiofluoride ester and glycidyl methacrylate; and the time of the mixed reaction in step (5) is 5-6 hours.

10. The environmentally friendly preparation method of the anti-stick sofa leather according to claim 8, characterized in that: The preparation method of the thiosulfate alcohol compound is as follows: 3 mol of diethylamine, 3 mol of mercaptoethanol and 3.5-4 L of anhydrous dichloromethane are added into a reaction kettle, stirred evenly, and then the materials in the reaction kettle are cooled to 0-2° C., 3 mol of carbon disulfide is then dripped into the reaction kettle, and then 3.2-3.5 mol of triethylamine is slowly added. After 5-8 minutes, an anhydrous dichloromethane solution containing 3 mol of carbon tetrabromide is added, and the reaction is stirred at room temperature for 4-6 hours. After the reaction is completed, the thiosulfate alcohol compound is obtained by purification.

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