Nanoparticle modified polyurethane synthetic leather slurry and preparation method thereof

Abstract

The invention relates to the technical field of synthetic leather materials, and discloses nano particle modified polyurethane synthetic leather slurry and a preparation method thereof. Comprising the following operation steps: uniformly mixing nanoparticle-based polyurethane, a wetting agent, a thermal expansion microcapsule, a defoaming agent, deionized water and a thickening agent to obtain polyurethane synthetic leather slurry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of synthetic leather materials, and particularly relates to a kind of nano-particle modified polyurethane synthetic leather slurry and a preparation method thereof. BACKGROUND

[0002] Polyurethane synthetic leather has become an ideal substitute for natural leather in the field of automotive interior due to its excellent simulation, flexibility and durability, and is widely used in components such as seats, steering wheels, door panels and instrument panels; however, the shortcomings of traditional polyurethane synthetic leather in terms of moisture permeability and hydrophobicity significantly affect the comfort of automobile driving and riding; especially in high temperature and high humidity environment, its poor moisture regulation capacity can easily cause the surface of the seat to be hot and uncomfortable to touch, and even affect the long-term riding experience.

[0003] In the prior art, nano-silica, montmorillonite and nano-titanium dioxide can be introduced into the polyurethane matrix through physical blending or in-situ hybridization to form a micro-nano porous structure in the coating, which can improve the air permeability, and the high specific surface area and interface enhancement effect of the nano-particles can improve the mechanical properties of the material; however, increasing the air permeability usually requires increasing the porosity or hydrophilicity of the coating, which can reduce the water resistance and lead to a decrease in the performance of the synthetic leather.

[0004] In view of the above, it is of great significance to prepare a kind of nano-particle modified polyurethane synthetic leather slurry to solve the above problems. SUMMARY

[0005] The present application aims to provide a kind of nano-particle modified polyurethane synthetic leather slurry and a preparation method thereof to solve the problems in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions: A preparation method of a nano-particle modified polyurethane synthetic leather slurry, comprising the following operation steps: Step 1: (1) uniformly mix double bond-based polyurethane, 1,4-butanediol dimethyl acrylate, acrylonitrile, methyl acrylate and methyl methacrylate in DMF (N,N-dimethylformamide), then uniformly mix benzoyl peroxide and a blowing agent to obtain an oil phase; uniformly mix sodium hydroxide and sodium chloride in deionized water, uniformly stir polyvinylpyrrolidone, and uniformly stir sodium nitrite to obtain an aqueous phase; (2) mix the aqueous phase and the oil phase, then emulsify in a mixing emulsifier for 10-15 minutes, transfer to a flask, introduce nitrogen, heat to 65-70℃, seal and stir for 18-22 hours, cool to room temperature, filter, wash and dry to obtain heat-expandable microcapsules; Step 2: uniformly mix the nanoparticle-based polyurethane, wetting agent, heat-expandable microcapsule, defoaming agent, deionized water, and thickening agent to obtain a polyurethane synthetic leather slurry.

[0007] More preferably, the raw materials of the polyurethane synthetic leather slurry include the following components: 100 parts of nanoparticle-based polyurethane, 8-15 parts of heat-expandable microcapsule, 0.7-1 part of wetting agent, 0.3-0.6 part of defoaming agent, 1-1.5 parts of thickening agent, and 40-50 parts of deionized water.

[0008] More preferably, the raw materials of the oil phase include the following components: 1-3 parts of double bond-based polyurethane, 2-4 parts of 1,4-butanediol dimethyl acrylate, 2.3-3 parts of acrylonitrile, 1-1.5 parts of methyl acrylate, 4-6 parts of methyl methacrylate, 0.5-1 part of benzoyl peroxide, 1.2-2 parts of foaming agent, and 8-10 parts of DMF; the raw materials of the water phase include the following components: 1-1.6 parts of sodium hydroxide, 5-9 parts of sodium chloride, 2-5 parts of polyvinylpyrrolidone, 0.7-1 part of sodium nitrite, and 30-40 parts of deionized water; and the mass ratio of the oil phase to the water phase is 1:(4.3-5).

[0009] More preferably, the preparation method of the nanoparticle-based polyurethane includes the following steps: ultrasonic dispersion of amino carbon nanotubes in DMF to obtain a mixed solution; heating and melting of polytetrahydrofuran ether diol and polycarbonate diol at 100-110℃, cooling to 40-50℃, and then adding isophorone diisocyanate; heating to 55-60℃ and stirring for 1-2 hours; uniformly mixing the catalyst and DMF, heating to 70-75℃, and continuing to stir for 1-2 hours; adding DMPA-DMF and stirring for 30-35 minutes; dropwise adding the mixed solution, continuing to stir for 1.8-2.5 hours; cooling to 50-55℃, adding triethylamine and stirring for 30-40 minutes; cooling to room temperature; adding the defoaming agent aqueous solution, stirring at 1400-1500 r / min until the oil-in-water phase inversion, and then adding diethylenetriamine and continuing to stir for 2-3 hours; removing DMF by reduced pressure distillation, filtering through a 100-150 mesh filter, and obtaining the nanoparticle-based polyurethane.

[0010] More preferably, the raw materials of the nanoparticle-based polyurethane include the following components: 6-8 parts of polytetrahydrofuran ether diol, 3-4 parts of polycarbonate diol, 10-13 parts of isophorone diisocyanate, 0.03-0.05 parts of catalyst, 2-4 parts of DMPA (2,2-dihydroxymethyl propionic acid), 0.9-1.4 parts of amino carbon nanotubes, 3-6 parts of triethylamine, 60-80 parts of defoaming agent aqueous solution, and 0.5-0.8 parts of diethylenetriamine; and the concentration of the defoaming agent in the defoaming agent aqueous solution is 0.05-0.07 wt%.

[0011] In the scheme, the preparation method of the aminated carbon nanotube is as follows: 3 parts of carbon nanotube are added into concentrated nitric acid and concentrated sulfuric acid with a mass ratio of 3:1, ultrasonic dispersion is carried out for 7 hours, centrifugal washing is carried out until neutral, drying is carried out, and acidified carbon nanotube is obtained; dilute hydrochloric acid is used to adjust the pH of anhydrous ethanol to 5, 5 parts of gamma-aminopropyl triethoxysilane is added and stirred for 30 minutes, 0.4 parts of acidified carbon nanotube is added and ultrasonic dispersion is carried out, stirring is carried out at 65 DEG C for 6 hours, filtration is carried out, washing with acetone is carried out for multiple times, and drying is carried out, and aminated carbon nanotube is obtained.

[0012] More preferably, the preparation method of the double bond based polyurethane is as follows: (1) the aminated nanosilica is ultrasonic dispersed in toluene, butylated hydroxyl toluene is added, stirring is carried out in an ice water bath for 40-50 minutes, 2-hydroxyethyl acrylate is added and uniformly mixed for 10-15 minutes, the temperature is increased to 40-45 DEG C, and stirring is carried out for 6-7 hours, the aminated nanosilica-toluene is added, and stirring is continuously carried out for 30-40 minutes, hexane washing is carried out, and drying is carried out, and hydroxyethyl ester-nanosilica is obtained; (2) polytetrahydrofuran ether diol is vacuum dehydrated for 45-60 minutes, is mixed with isophorone diisocyanate and acetone, a catalyst is added, stirring is carried out at 90-95 DEG C for 1-1.5 hours, the temperature is decreased to 75-80 DEG C, hydroxyethyl ester-nanosilica is added and stirred for 2-3 hours, the temperature is decreased to 50-55 DEG C, hydroxypropyl acrylate is added, and stirring is continuously carried out for 2-3 hours, and double bond based polyurethane is obtained.

[0013] More preferably, the mass ratio of the aminated nanosilica, butylated hydroxyl toluene and 2-hydroxyethyl acrylate is (0.4-0.6):(0.05-0.07):1.5; the raw materials of the double bond based polyurethane include the following components: 5-7 parts of polytetrahydrofuran ether diol, 8-10 parts of isophorone diisocyanate, 0.04-0.06 parts of a catalyst, 1-3 parts of hydroxyethyl ester-nanosilica, 10-15 parts of acetone and 2.5-3.5 parts of hydroxypropyl acrylate.

[0014] In the scheme, the preparation method of the aminated nanosilica is as follows: 2 parts of nanosilica are ultrasonic dispersed in 60 parts of anhydrous ethanol, and nanosilica mixed solution is obtained and reserved; 8 parts of gamma-aminopropyl triethoxysilane is added into 12 parts of deionized water and uniformly mixed, the nanosilica mixed solution is added, refluxing is carried out at 70 DEG C for 4 hours, the temperature is cooled to room temperature, repeated washing with anhydrous ethanol and suction filtration are carried out until the filtrate is transparent, the filter cake is dried, and aminated nanosilica is obtained; the part is a mass part.

[0015] Compared with the prior art, the present application has the following beneficial effects: In the scheme, the polyurethane, wetting agent, defoaming agent, water, thickening agent are uniformly mixed to obtain the synthetic leather slurry; in the scheme, polytetrahydrofuran ether diol and polycarbonate diol are used as polyols for preparing polyurethane; wherein, the polytetrahydrofuran ether diol has good flexibility, hydrophobicity and low temperature flexibility; the polycarbonate diol has certain rigidity and can improve the mechanical properties of synthetic leather; the combination of the two can make the synthetic leather not easy to deform, but the air permeability is poor; therefore, in the scheme, carbon nanotubes are introduced into the polyurethane; the carbon nanotubes have a hollow structure and can form a gas transmission network; in the scheme, the amino groups on the amino-functionalized carbon nanotubes react with the isocyanate groups on the remaining isophorone diisocyanate, introducing carbon nanotubes into the polyurethane, thereby improving the air permeability and water resistance of the polyurethane synthetic leather.

[0016] Among them, the carbon nanotubes mainly provide air permeability by constructing channels in the polyurethane matrix through their hollow tubular structure, but this air permeability effect is relatively stable; and the rigidity of the polyurethane will also be improved, which will affect the mechanical properties of the synthetic leather; In order to improve the air permeability while not affecting the hydrophobicity, and balance the rigidity brought by the carbon nanotubes, heat expandable microcapsules are added to the synthetic leather slurry, which is beneficial to improve the mechanical properties of the synthetic leather; in the scheme, the heat expandable microcapsules have thermal responsiveness and will swell or shrink at different temperatures, complementing the micropores formed by the carbon nanotubes to form a multi-scale pore structure, further improving the overall air permeability.

[0017] In the scheme, if the heat expandable microcapsules have poor compatibility with the polyurethane, they will agglomerate in the polyurethane synthetic leather slurry, affecting the performance; in order to solve the problem of compatibility between the heat expandable microcapsules and the polyurethane; in the scheme, double bond-based polyurethane is introduced into the oil phase of the heat expandable microcapsules, so that it can copolymerize with acrylic monomers; thereby improving the interfacial compatibility of the heat expandable microcapsules and the polyurethane.

[0018] In the scheme, polytetrahydrofuran ether diol and hydroxyethyl ester-nano silicon dioxide are used as polyols for preparing double bond based polyurethane, wherein the hydroxyethyl ester-nano silicon dioxide can assist water vapor transmission, but its hydrophilicity is high, which can affect the water resistance of synthetic leather, so the content of hydroxyethyl ester-nano silicon dioxide should not be too high, and it is capped by hydrophobic hydroxypropyl acrylate to obtain double bond based polyurethane, but the double bond based polyurethane itself is a long chain prepolymer, which may form local crosslinking points after double bond reaction, so that the crosslinking network is not uniform, which can affect the performance of the polyurethane synthetic leather slurry; in order to solve this problem, a small molecule crosslinking agent (1,4-butanediol dimethacrylate) is added as a bridge in the scheme to connect multiple polymer chains to form a uniform and dense network, and it has hydrophobicity, which is beneficial to improve the performance of synthetic leather slurry by synergistic effect with double bond based polyurethane; wherein, the polytetrahydrofuran ether diol and the nano particle based polyurethane can optimize the compatibility of the wall material and the flexibility of the capsule wall, and provide basic conditions for the formation and expansion of the microcapsule; the hydroxyethyl ester-nano silicon dioxide can enhance the capsule wall and control the interface, both of which can improve the structural stability and functional synergy of the microcapsule, improve the dispersity of the thermal expansion microcapsule in the synthetic leather slurry, and thus enhance the performance of the synthetic leather. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] In the following specific embodiments, the parts are mass parts, and in the present embodiment, it should be noted that there is no special restriction on the purchase manufacturer of all raw materials involved in the present application, which includes the following examples: The code number of the nano-silica is PA92467; the code number of the carbon nanotube is BD0943; the CAS number of the 2-hydroxyethyl acrylate is 818-61-1; the CAS number of the butyl hydroxy toluene is 128-37-0; the CAS number of the 2,2-dimethylol propionic acid is 4767-03-7; the code number of the polytetramethylene ether glycol is PTMEG, and the molecular weight is 2000; the code number of the polycarbonate diol is KA679746, and the molecular weight is 2000; the CAS number of the isophorone diisocyanate is 4098-71-9; the CAS number of the hydroxypropyl acrylate is 25584-83-2; the defoaming agent is polyether defoaming agent (GPE), and the code number is 1; the CAS number of the diethylenetriamine is 111-40-0; the CAS number of the acrylonitrile is 107-13-1; the CAS number of the methyl acrylate is 96-33-3; the CAS number of the methyl methacrylate is 80-62-6; the CAS number of the benzoyl peroxide (initiator) is 94-36-0; the CAS number of the n-pentane (foaming agent) is 109-66-0; the type of the polyvinylpyrrolidone is PVPK30; the type of the thickening agent is HT-105; and the wetting agent is polyether modified silicone oil, and the type is X220.

[0021] The preparation method of the nanoparticle-based polyurethane is as follows: 1.4 parts of aminated carbon nanotubes are ultrasonically dispersed in 4 parts of DMF to obtain a mixed solution; 6 parts of polytetramethylene ether glycol and 3 parts of polycarbonate diol are heated and melted at 100°C, cooled to 40°C, 10 parts of isophorone diisocyanate is added, the temperature is increased to 55°C, and stirring is performed for 1 hour, 0.03 parts of a catalyst (dibutyltin dilaurate) and 6 parts of DMF are uniformly mixed, the temperature is increased to 70°C, and stirring is continuously performed for 1.5 hours, DMPA-DMF (2.5 parts of DMPA is added to 2 parts of DMF) is stirred for 30 minutes, the mixed solution is added dropwise, and stirring is continuously performed for 1.8 hours, 4 parts of triethylamine is added at a temperature of 50°C and stirred for 30 minutes, the temperature is reduced to room temperature, stirring is performed at 1400 r / min, 70 parts of a defoaming agent aqueous solution (the concentration of the defoaming agent is 0.05 wt%) is added, and after phase inversion of the oil-in-water, 0.7 parts of diethylenetriamine is continuously stirred for 2 hours, DMF is removed by distillation under reduced pressure, and filtration is performed through a 120-mesh filter to obtain the nanoparticle-based polyurethane.

[0022] Example 1: A preparation method of a nanoparticle-modified polyurethane synthetic leather slurry, comprising the following operation steps: Preparation: the preparation method of the double bond based polyurethane is as follows: (1) amino-nano-silica, butyl hydroxyl toluene, and 2-hydroxyethyl acrylate are weighed according to a mass ratio of 0.4:0.05:1.5; the amino-nano-silica is ultrasonically dispersed in toluene, butyl hydroxyl toluene is added, stirring is carried out under ice water bath for 40 minutes, 2-hydroxyethyl acrylate is added, uniform mixing is carried out for 15 minutes, the temperature is increased to 40 DEG C, stirring is carried out for 6 hours, amino-nano-silica-toluene is added, and stirring is continued for 40 minutes; hexane is used for washing, and drying is carried out, thereby obtaining hydroxyethyl acrylate-nano-silica; (2) 6 parts of polytetrahydrofuran ether diol are vacuum dehydrated for 45 minutes, and then mixed with 8 parts of isophorone diisocyanate and 10 parts of acetone, 0.06 parts of a catalyst (dibutyl tin dilaurate) is added, stirring is carried out at 90 DEG C for 1.5 hours, the temperature is decreased to 80 DEG C, 1.8 parts of hydroxyethyl acrylate-nano-silica is added, and stirring is carried out for 2 hours, the temperature is decreased to 55 DEG C, 2.5 parts of hydroxypropyl acrylate is added, and stirring is continued for 3 hours, thereby obtaining the double bond based polyurethane; Step 1: (1) 2 parts of double bond based polyurethane, 3 parts of 1, 4-butanediol dimethacrylate, 2.5 parts of acrylonitrile, 1.5 parts of methyl acrylate, 5 parts of methyl methacrylate, 0.5 parts of benzoyl peroxide, and 1.3 parts of a foaming agent (n-pentane) are added into 8 parts of DMF to obtain an oil phase; 1.5 parts of sodium hydroxide and 6 parts of sodium chloride are added into 35 parts of deionized water to obtain an aqueous phase; (2) the aqueous phase and the oil phase are mixed according to a mass ratio of 1:4.5, and then emulsified in a mixing emulsifier for 15 minutes; the emulsion is transferred into a flask, nitrogen is introduced, the temperature is increased to 65 DEG C, and stirring is carried out for 22 hours; after cooling to room temperature, filtration, washing, and drying are carried out, thereby obtaining the heat-expandable microcapsule; Step 2: 100 parts of nano-particle based polyurethane, 0.7 parts of a wetting agent, 8 parts of the heat-expandable microcapsule, 0.6 parts of an antifoaming agent, 45 parts of deionized water, and 1 part of a thickening agent are uniformly mixed to obtain a polyurethane synthetic leather slurry.

[0023] Example 2: a preparation method of a nano-particle modified polyurethane synthetic leather slurry, comprising the following operation steps: Preparation: the preparation method of the double bond based polyurethane is as follows: (1) amino-nano-silica, butyl hydroxyl toluene, and 2-hydroxyethyl acrylate are weighed according to a mass ratio of 0.4:0.05:1.5; the amino-nano-silica is ultrasonically dispersed in toluene, butyl hydroxyl toluene is added, stirring is carried out under ice water bath for 40 minutes, 2-hydroxyethyl acrylate is added, uniform mixing is carried out for 15 minutes, the temperature is increased to 40 DEG C, stirring is carried out for 6 hours, amino-nano-silica-toluene is added, and stirring is continued for 40 minutes; hexane is used for washing, and drying is carried out, thereby obtaining hydroxyethyl acrylate-nano-silica; (2) 6 parts of polytetrahydrofuran ether diol are vacuum dehydrated for 45 minutes, and then mixed with 8 parts of isophorone diisocyanate and 10 parts of acetone, 0.06 parts of a catalyst (dibutyl tin dilaurate) is added, stirring is carried out at 90 DEG C for 1.5 hours, the temperature is decreased to 80 DEG C, 1.8 parts of hydroxyethyl acrylate-nano-silica is added, and stirring is carried out for 2 hours, the temperature is decreased to 55 DEG C, 2.5 parts of hydroxypropyl acrylate is added, and stirring is continued for 3 hours, thereby obtaining the double bond based polyurethane; Step 1: (1) 2 parts of double bond based polyurethane, 3 parts of 1, 4-butanediol dimethacrylate, 2.5 parts of acrylonitrile, 1.5 parts of methyl acrylate, 5 parts of methyl methacrylate, 0.5 parts of benzoyl peroxide, and 1.3 parts of a foaming agent (n-pentane) are added into 8 parts of DMF to obtain an oil phase; 1.5 parts of sodium hydroxide and 6 parts of sodium chloride are added into 35 parts of deionized water to obtain an aqueous phase; (2) the aqueous phase and the oil phase are mixed according to a mass ratio of 1:4.5, and then emulsified in a mixing emulsifier for 15 minutes; the emulsion is transferred into a flask, nitrogen is introduced, the temperature is increased to 65 DEG C, and stirring is carried out for 22 hours; after cooling to room temperature, filtration, washing, and drying are carried out, thereby obtaining the heat-expandable microcapsule; Step 2: 100 parts of nano-particle based polyurethane, 0.8 parts of a wetting agent, 10 parts of the heat-expandable microcapsule, 0.6 parts of an antifoaming agent, 45 parts of deionized water, and 1 part of a thickening agent are uniformly mixed to obtain a polyurethane synthetic leather slurry.

[0024] Example 3: a preparation method of a nano-particle modified polyurethane synthetic leather slurry, comprising the following operation steps: Preparation: the preparation method of the double bond based polyurethane is as follows: (1) amino-nano-silica, butyl hydroxyl toluene, 2-hydroxyethyl acrylate are weighed according to the mass ratio of 0.4:0.05:1.5; the amino-nano-silica is ultrasonically dispersed in toluene, butyl hydroxyl toluene is added, stirring under ice water bath for 40 minutes, 2-hydroxyethyl acrylate is added and uniformly mixed for 15 minutes, the temperature is raised to 40℃ and stirring is carried out for 6 hours, amino-nano-silica-toluene is added, and stirring is continued for 40 minutes, hexane is used for washing, and drying is carried out, to obtain hydroxyethyl acrylate-nano-silica; (2) 6 parts of polytetrahydrofuran ether diol are vacuum dehydrated for 45 minutes, and then mixed with 8 parts of isophorone diisocyanate and 10 parts of acetone, 0.06 parts of catalyst (dibutyl tin dilaurate) is added, stirring is carried out at 90℃ for 1.5 hours, the temperature is lowered to 80℃, 1.8 parts of hydroxyethyl acrylate-nano-silica is added and stirring is carried out for 2 hours, the temperature is lowered to 55℃, 2.5 parts of hydroxypropyl acrylate is added, and stirring is continued for 3 hours, to obtain double bond based polyurethane; Step 1: (1) 2 parts of double bond based polyurethane, 3 parts of 1,4-butanediol dimethacrylate, 2.5 parts of acrylonitrile, 1.5 parts of methyl acrylate, 5 parts of methyl methacrylate, 0.5 parts of benzoyl peroxide, 1.3 parts of foaming agent (n-pentane) are added into 8 parts of DMF and uniformly mixed, to obtain oil phase; 1.5 parts of sodium hydroxide, 6 parts of sodium chloride are added into 35 parts of deionized water and uniformly mixed, 2 parts of polyvinylpyrrolidone is added and uniformly stirred, 1 part of sodium nitrite is added and uniformly stirred, to obtain water phase; (2) the water phase and the oil phase are mixed according to the mass ratio of 1:4.5, then emulsified in a mixing emulsifier for 15 minutes, transferred into a flask, nitrogen is introduced, the temperature is raised to 65℃, and stirring is carried out for 22 hours, the temperature is cooled to room temperature, filtration, washing and drying are carried out, to obtain thermal expansion microcapsule; Step 2: 100 parts of nano-particle based polyurethane, 0.8 parts of wetting agent, 15 parts of thermal expansion microcapsule, 0.6 parts of defoaming agent, 45 parts of deionized water, 1 part of thickening agent are uniformly mixed, to obtain polyurethane synthetic leather slurry.

[0025] Comparative Example 1: based on Example 3, carbon nanotubes are replaced by nano-silica, and the remaining operation steps are the same; Preparation: the preparation method of the nanoparticle-based polyurethane is as follows: 1.4 parts of aminated nanosilica is ultrasonically dispersed in 4 parts of DMF to obtain a mixed solution; 6 parts of polytetrahydrofuran ether diol and 3 parts of polycarbonate diol are heated and melted at 110℃, cooled to 40℃, 10 parts of isophorone diisocyanate is added, heated to 55℃ and stirred for 1 hour, 0.03 parts of a catalyst (dibutyl tin dilaurate) and 6 parts of DMF are uniformly mixed, heated to 70℃, and continuously stirred for 1.5 hours, 2.5 parts of DMPA is added to 2 parts of DMF to obtain DMPA-DMF, stirred for 30 minutes, the mixed solution is added dropwise, and the stirring is continued for 1.8 hours, 4 parts of triethylamine is added at 50℃ and stirred for 30 minutes, cooled to room temperature, and stirred at 1400r / min, 70 parts of an antifoaming agent aqueous solution (the concentration of the antifoaming agent is 0.05wt%) is added, and after phase inversion, 0.7 parts of diethylenetriamine is added and stirred for 2 hours, DMF is removed by distillation under reduced pressure, filtered through a 120-mesh filter screen, and the nanoparticle-based polyurethane is obtained.

[0026] Comparative Example 2 is based on Example 3, and the aminated carbon nanotube is directly mixed with the polyurethane; the remaining operation steps are the same. Preparation: the preparation method of the polyurethane is as follows: 6 parts of polytetrahydrofuran ether diol and 3 parts of polycarbonate diol are heated and melted at 100℃, cooled to 40℃, 10 parts of isophorone diisocyanate is added, heated to 55℃ and stirred for 1 hour, 0.03 parts of a catalyst and 6 parts of DMF are uniformly mixed, heated to 70℃, and continuously stirred for 1.5 hours, 2.5 parts of DMPA is added to 2 parts of DMF to obtain DMPA-DMF, stirred for 30 minutes, cooled to 50℃, 4 parts of triethylamine is added and stirred for 30 minutes, cooled to room temperature, and stirred at 1400r / min, 70 parts of an antifoaming agent aqueous solution (the concentration of the antifoaming agent is 0.05wt%) is added, and after phase inversion, 0.7 parts of diethylenetriamine is added and stirred for 2 hours, DMF is removed by distillation under reduced pressure, filtered through a 120-mesh filter screen, and the polyurethane is obtained. 100 parts of the polyurethane, 0.8 parts of a wetting agent, 1.4 parts of aminated carbon nanotubes, 15 parts of thermally expandable microcapsules, 0.6 parts of an antifoaming agent, 45 parts of deionized water, and 1 part of a thickening agent are uniformly mixed to obtain a polyurethane synthetic leather slurry.

[0027] Comparative Example 3 is based on Example 3, and no thermally expandable microcapsules are added; the remaining operation steps are the same. 100 parts of the nanoparticle-based polyurethane, 0.8 parts of a wetting agent, 0.6 parts of an antifoaming agent, 45 parts of deionized water, and 1 part of a thickening agent are uniformly mixed to obtain a polyurethane synthetic leather slurry.

[0028] Comparative Example 4 is based on Example 3, and no small molecule crosslinking agent (1,4-butanediol dimethacrylate) is added to the thermally expandable microcapsules; the remaining operation steps are the same. Step 1: (1) 2 parts of double-bond polyurethane, 2.5 parts of acrylonitrile, 1.5 parts of methyl acrylate, 5 parts of methyl methacrylate, 0.5 parts of benzoyl peroxide, and 1.3 parts of a foaming agent (n-pentane) are added to 8 parts of DMF and mixed evenly to obtain an oil phase; 1.5 parts of sodium hydroxide and 6 parts of sodium chloride are added to 35 parts of deionized water and mixed evenly, 2 parts of polyvinyl pyrrolidone are added and stirred evenly, and 1 part of sodium nitrite is added and stirred evenly to obtain an aqueous phase; (2) After mixing the aqueous phase and the oil phase in a mass ratio of 1:4.5, the mixture was emulsified in a mixing emulsifier for 15 minutes, the flask was inverted, nitrogen was introduced, the temperature was raised to 65°C, the mixture was sealed and stirred for 22 hours, and the mixture was cooled to room temperature, filtered, washed, and dried to obtain thermally expandable microcapsules; Step 2: 100 parts of nanoparticle-based polyurethane, 0.8 parts of wetting agent, 15 parts of thermal expansion microcapsules, 0.6 parts of defoaming agent, 45 parts of deionized water, and 1 part of thickener are uniformly mixed to obtain a polyurethane synthetic leather slurry.

[0029] Comparative Example 5 is based on Example 3, except that hydroxyethyl ester-nanosilica is not introduced into the double-bond polyurethane; the remaining steps are the same; The preparation method of double-bond polyurethane is as follows: 6 parts of polytetramethylene glycol are vacuum dehydrated for 45 minutes, uniformly mixed with 8 parts of isophorone diisocyanate and 10 parts of acetone, 0.06 parts of catalyst are added, stirred at 90°C for 2 hours, cooled to 55°C, 2.5 parts of hydroxypropyl acrylate are added, and stirring is continued for 3 hours to obtain double-bond polyurethane.

[0030] Testing experiment: The base fabric (made of polyester woven fabric) was immersed in the polyurethane synthetic leather slurry prepared in Examples 1 to 3 and Comparative Examples 1 to 5, and then taken out and cured to obtain synthetic leather; (1) Testing the tensile strength (MPa) of Examples 1 to 3 and Comparative Examples 1 to 5; (2) Testing the water vapor permeability of Examples 1 to 3 and Comparative Examples 1 to 5: The synthetic leathers prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were immersed in deionized water for 20 days, dried, and the peel strength (N / 3 cm) was tested, as shown in Table 1.

[0031] Table 1 Water vapor permeability (mg / 10 cm2·24 h) Tensile strength (MPa) Peeling strength (N / 3 cm) Example 1 228.5 26.1 121.8 Example 2 232.2 28.2 124.4 Example 3 234.4 29.7 128.6 Comparative Example 1 226.3 29.9 127.1 Comparative Example 2 221.6 24.2 123.7 Comparative Example 3 204.2 20.7 118.9 Comparative Example 4 212.7 22.8 121.3 Comparative Example 5 218.5 25.2 129.4 Conclusion: Comparative Example 1 is based on Example 3, except that the carbon nanotubes are replaced with nanosilica. Because the carbon nanotubes are hollow and do not form a multi-scale pore structure with the thermally expandable microcapsules, and the carbon nanotubes have a certain degree of hydrophobicity, the performance of Comparative Example 1 is reduced. Comparative Example 2 is based on Example 3, except that the amino-treated carbon nanotubes are directly mixed with polyurethane. This results in reduced dispersibility of the carbon nanotubes in the polyurethane synthetic leather slurry and interfacial compatibility with the thermally expandable microcapsules, and increased hydrophilicity, resulting in reduced performance of Comparative Example 2. Comparative Example 3 is based on Example 3, without the addition of the heat-expandable microcapsules; thus resulting in a decrease in the performance of the synthetic leather; Comparative Example 4 is based on Example 3, without the addition of the small molecule crosslinking agent (1,4-butanediol dimethacrylate) to the heat-expandable microcapsules; thus resulting in a non-uniform crosslinking network, which affects the performance of the heat-expandable microcapsules, and thus a decrease in the performance of Comparative Example 4; Comparative Example 5 is based on Example 3, without the introduction of the hydroxyethyl acrylate-nano-silica into the double bond-based polyurethane; thus resulting in an increase in the water resistance due to the lack of hydrophilic groups, and thus an increase in the peeling strength, and an increase in the air permeability due to the nano-silica, thus resulting in a decrease in the air permeability of Comparative Example 5.

[0032] It is apparent to a person skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but can be implemented in other particular forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the present application being defined by the appended claims rather than the above description, and all changes coming within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A method for preparing a nanoparticle-modified polyurethane synthetic leather slurry, characterized in that: The following steps are included: Step 1: (1) Double-bond polyurethane, 1,4-butanediol dimethacrylate, acrylonitrile, methyl acrylate, and methyl methacrylate are added to DMF and mixed evenly, and then benzoyl peroxide and a foaming agent are added in sequence and mixed evenly to obtain an oil phase; sodium hydroxide and sodium chloride are added to deionized water and mixed evenly, polyvinyl pyrrolidone is added and stirred evenly, and sodium nitrite is added and stirred evenly to obtain an aqueous phase; (2) After mixing the aqueous phase and the oil phase, emulsify them in a mixing emulsifier for 10-15 minutes, invert the flask, introduce nitrogen, heat to 65-70°C, seal and stir for 18-22 hours, cool to room temperature, filter, wash and dry to obtain thermal expansion microcapsules; Step 2: uniformly mix the nanoparticle-based polyurethane, wetting agent, thermal expansion microcapsules, defoaming agent, deionized water, and thickener to obtain a polyurethane synthetic leather slurry.

2. The method for preparing a nanoparticle-modified polyurethane synthetic leather slurry according to claim 1, wherein: The raw materials of the polyurethane synthetic leather slurry include the following components: 100 parts by mass of nanoparticle-based polyurethane, 8-15 parts of thermal expansion microcapsules, 0.7-1 parts of wetting agent, 0.3-0.6 parts of defoaming agent, 1-1.5 parts of thickener, and 40-50 parts of deionized water.

3. The method for preparing a nanoparticle-modified polyurethane synthetic leather slurry according to claim 1, wherein: The raw materials of the oil phase include the following components, calculated by mass: 1-3 parts of double-bond polyurethane, 2-4 parts of 1,4-butanediol dimethacrylate, 2.3-3 parts of acrylonitrile, 1-1.5 parts of methyl acrylate, 4-6 parts of methyl methacrylate, 0.5-1 part of benzoyl peroxide, 1.2-2 parts of foaming agent, and 8-10 parts of DMF; the raw materials of the water phase include the following components, calculated by mass: 1-1.6 parts of sodium hydroxide, 5-9 parts of sodium chloride, 2-5 parts of polyvinyl pyrrolidone, 0.7-1 part of sodium nitrite, and 30-40 parts of deionized water; the mass ratio of the oil phase to the water phase is 1:(4.3-5).

4. The method for preparing a nanoparticle-modified polyurethane synthetic leather slurry according to claim 2, wherein: The preparation method of the nanoparticle-based polyurethane comprises the following steps: ultrasonically dispersing amino carbon nanotubes in DMF to obtain a mixed solution; heating polytetramethylene ether diol and polycarbonate diol at 100-110° C. to melt, cooling to 40-50° C., adding isophorone diisocyanate, heating to 55-60° C. and stirring for 1-2 hours, adding a catalyst and DMF and uniformly mixing, heating to 70-75° C. and continuously stirring for 1-2 hours, adding DMPA-DMF and stirring for 30-35 minutes, dropwise adding the mixed solution and continuously stirring for 1.8-2.5 hours, cooling to 50-55° C., adding triethylamine and stirring for 30-40 minutes, cooling to room temperature, adding a defoaming agent aqueous solution, stirring at 1400-1500 rpm until water-in-oil phase conversion occurs, adding diethylenetriamine and continuously stirring for 2-3 hours, removing DMF by reduced pressure distillation, and filtering through a 100-150 mesh filter to obtain the nanoparticle-based polyurethane.

5. The method for preparing a nanoparticle-modified polyurethane synthetic leather slurry according to claim 4, characterized in that: The raw materials of the nanoparticle-based polyurethane include the following components: 6-8 parts of polytetramethylene ether glycol, 3-4 parts of polycarbonate diol, 10-13 parts of isophorone diisocyanate, 0.03-0.05 parts of a catalyst, 2-4 parts of DMPA, 0.9-1.4 parts of amino-treated carbon nanotubes, 3-6 parts of triethylamine, 60-80 parts of a defoamer aqueous solution, and 0.5-0.8 parts of diethylenetriamine. In the defoamer aqueous solution, the concentration of the defoamer is 0.05-0.07 wt%.

6. The method for preparing a nanoparticle-modified polyurethane synthetic leather slurry according to claim 1, wherein: The preparation method of the double-bond polyurethane is as follows: (1) amino-type nano-silica is ultrasonically dispersed in toluene, butyl hydroxytoluene is added, and the mixture is stirred in an ice-water bath for 40-50 minutes, 2-hydroxyethyl acrylate is added, and the mixture is uniformly mixed for 10-15 minutes, the mixture is heated to 40-45°C, and the mixture is stirred for 6-7 hours, amino-type nano-silica-toluene is added, and the mixture is stirred for 30-40 minutes, washed with hexane, and dried to obtain hydroxyethyl ester-nano-silica; (2) polytetrahydrofuran ether glycol is vacuum-dehydrated for 45-60 minutes, the mixture is uniformly mixed with isophorone diisocyanate and acetone, a catalyst is added, the mixture is stirred at 90-95°C for 1-1.5 hours, the mixture is cooled to 75-80°C, hydroxyethyl ester-nano-silica is added, and the mixture is stirred for 2-3 hours, the mixture is cooled to 50-55°C, hydroxypropyl acrylate is added, and the mixture is stirred for 2-3 hours to obtain the double-bond polyurethane.

7. The method for preparing a nanoparticle-modified polyurethane synthetic leather slurry according to claim 6, characterized in that: The mass ratio of the amino-modified nano-silica, butylated hydroxytoluene, and 2-hydroxyethyl acrylate is (0.4-0.6):(0.05-0.07):1.5; the raw materials of the double-bond polyurethane include the following components: 5-7 parts by mass of polytetramethylene ether glycol, 8-10 parts of isophorone diisocyanate, 0.04-0.06 parts of a catalyst, 1-3 parts of hydroxyethyl ester-nano-silica, 10-15 parts of acetone, and 2.5-3.5 parts of hydroxypropyl acrylate.

8. A polyurethane synthetic leather slurry prepared according to the method for preparing a nanoparticle-modified polyurethane synthetic leather slurry according to any one of claims 1 to 7.