Preparation method and application of highly wear-resistant one-component waterborne polyurethane and its emulsion or dispersion, coating

Abstract

The present invention belongs to the technical field of functional polymer materials and waterborne polyurethane coating preparation, and discloses a highly wear-resistant single-component waterborne polyurethane and its emulsion or dispersion, and a preparation method and application of a coating. The present invention catalyzes a polyol, a small molecule diol, a catalyst and a diisocyanate, adds a crosslinking agent with a ditriazine structure to react, neutralizes, emulsifies and disperses to obtain a waterborne polyurethane emulsion or dispersion, and obtains a coating after coating and drying. The present invention introduces a ditriazine structure into the waterborne polyurethane, thereby improving the crosslinking degree of the polyurethane and the hydrogen bonding effect between molecules, giving the coating excellent wear resistance, hardness and mechanical properties, being easy to use, and having high cost performance, and having a wide range of uses in automobiles, electronic appliances, chemicals, leather finishing, engineering machinery, construction and other related fields.

Description

Technical Field

[0001] The invention belongs to the technical field of water-based coatings and functional polymer materials, and relates to a highly wear-resistant single-component water-based polyurethane and a preparation method and application of its emulsion or dispersion and coating film. Background Art

[0002] Waterborne polyurethane has excellent wear resistance and scratch resistance mechanical properties, as well as solvent resistance, radiation resistance and excellent low-temperature elasticity. It is widely used in the fields of wood, electronic appliances, engineering equipment, automobiles and leather finishing waterborne coatings and adhesives. The existing single-component waterborne polyurethane coating has poor wear resistance and cannot meet the actual use requirements. It is necessary to structurally design it to improve its comprehensive performance. The present invention introduces a ditriazine structure into the single-component polyurethane molecular chain to improve the wear resistance and other mechanical properties of the resin through a cross-linking reaction.

[0003] By constructing a cross-linked network in the polyurethane structure, the mechanical properties, water resistance and wear resistance of the coating can be effectively improved. Yu et al. (Polym.Chem., 2016, 7, 3913–3922) used trimethylpropane-tri-(β-n-aziridine) propionate (XR-100) as a cross-linking agent, and introduced polyether-modified polydimethylsiloxane (PDMS) and dodecafluoromethylacrylate (FMA) to prepare cross-linked waterborne polyurethane. Through cross-linking modification and the introduction of siloxane and fluorinated monomers, the comprehensive performance of waterborne polyurethane has been significantly improved: the water absorption rate has dropped to 3.48%, the swelling rate of n-heptane has dropped to 1.02%, the hardness has reached 6H, and the tensile strength has also increased to 33.2MPa. However, aziridine cross-linkers are toxic and expensive, and fluorinated monomers will pollute the environment during use, which is not conducive to environmental protection. Liang et al. (Pro.Org.Coat.150(2021)105972) used (3-(2-aminoethyl)aminopropyl)trimethoxysilane (AEAPTMS) as a cross-linker to prepare cross-linked waterborne polyurethane. The addition of AEAPTMS improved the tensile strength, water resistance, thermal stability and wear resistance of the material. Summary of the invention

[0004] In view of the shortcomings of the current one-component waterborne polyurethane coatings, such as poor wear resistance and mechanical properties, the purpose of the present invention is to provide a highly wear-resistant one-component waterborne polyurethane and its emulsion or dispersion, a preparation method and application of the coating, which effectively overcomes the above shortcomings.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A highly wear-resistant one-component waterborne polyurethane, wherein the polyurethane molecular chain contains the following structure:

[0007]

[0008] Where R is C 1～10 Alkyl, C 6～10 Alicyclic group, C 6～10 One or more of aromatic hydrocarbon groups;

[0009] A is the residue structure of diisocyanate without -NCO group;

[0010] B is a residue structure obtained by removing -OH from polyester polyol, polyether polyol, polycarbonate polyol or polypropylene glycol (PPG).

[0011] A method for preparing a highly wear-resistant one-component aqueous polyurethane emulsion or dispersion comprises the following steps:

[0012] According to the proportion, add polyol, hydrophilic chain extender, diisocyanate, catalyst and solvent into a reaction kettle with stirring and condenser, pass N2 or other inert gas protection, and react at 50-100°C for 2-15h; add crosslinking agent and small molecule diol and react at 50-100°C for 2-15h to obtain polyurethane prepolymer.

[0013] Then, the prepolymer is cooled to 15-40° C., and a small amount of solvent is added to adjust the viscosity; a neutralizing agent is added for neutralization, and water is added for emulsification, and the solvent is removed by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion.

[0014] A method for preparing a highly wear-resistant single-component waterborne polyurethane coating comprises applying, drying and curing the above-mentioned waterborne polyurethane emulsion or dispersion to obtain the waterborne polyurethane coating.

[0015] The diisocyanate is one or a mixture of two or more of toluene diisocyanate TDI, hexamethylene diisocyanate HDI, diphenylmethane diisocyanate MDI, and isophorone diisocyanate IPDI, and the R value is the ratio of the molar number of isocyanate group to the hydroxyl group, which is 1.0-2.0.

[0016] The polyol is one of polyester polyol, polyether polyol, polycarbonate polyol and polypropylene glycol (PPG), or a mixture of two or more thereof; preferably polyester polyol or polycarbonate polyol.

[0017] The molecular weight of the polyol is 1000-3000 g / mol, preferably 1000-2000 g / mol, particularly preferably 1000 g / mol or 2000 g / mol. The amount of the polyol is set by the operator.

[0018] The hydrophilic chain extender is one or a mixture of 2,2-dimethylol propionic acid DMPA and 2,2-dimethylol butyric acid DMBA, and the mass content of the hydrophilic chain extender is 1.5-15wt% of all the reaction raw materials (polyol+hydrophilic chain extender+diisocyanate).

[0019] The catalyst is one or both of stannous octoate and dibutyltin dilaurate, and the mass ratio of the catalyst to the polyol is 0.1-10wt%.

[0020] The cross-linking agent is synthesized by reacting dicyandiamide and adiponitrile, and its chemical structure is shown in formula (II):

[0021]

[0022] Where R is C 1～10 Alkyl, C 6～10 Alicyclic or C 6～10 One or more of the aromatic hydrocarbon groups; preferably a C4 alkyl group, and the preferred compound is 6,6'-(1,4-butane)bis(1,3,5-triazine-2,4-diamine (BBTDA). The number of moles of the crosslinking agent is the number of moles of the remaining isocyanate groups.

[0023] The small molecule diol is one of ethylene glycol, propylene glycol, and butanediol, or a mixture of two or more thereof; preferably 1,4-butanediol.

[0024] The solvent is one or a mixture of two or more of acetone, butanone, ethylene glycol methyl ether, and trifluoroacetic acid. The amount of solvent used at the beginning of the reaction is 1-8 times the total mass of all the reaction raw materials. If the solution is relatively viscous, a small amount of solvent can be added. The amount of deionized water used depends on the dispersion of the emulsion.

[0025] The neutralizing agent is one or both of triethylamine and NaOH.

[0026] The highly wear-resistant one-component water-based polyurethane emulsion is used as a coating or adhesive in the fields of automobiles, electronic appliances, engineering machinery, leather finishing, chemicals and wood products.

[0027] Beneficial effects of the present invention:

[0028] The present invention starts from the mechanism that affects the wear resistance of polyurethane, introduces rigid groups into the polyurethane structure by adding a bistriazine structure crosslinking agent, and simultaneously improves the crosslinking density of polyurethane, strengthens the hydrogen bonding between molecular chains, constructs a chemical and physical double crosslinking network, and significantly improves the hardness and wear resistance of the polyurethane coating. The coating prepared by using the single-component water-based polyurethane emulsion or dispersion of the present invention has excellent mechanical properties and outstanding hardness and wear resistance, and has broad application prospects in the fields of automobiles and ships, electronic appliances, chemicals, leather finishing, engineering machinery, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the infrared spectrum of the cross-linking agent BBTDA in Example 1.

[0030] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of the cross-linking agent BBTDA in Example 1.

[0031] Figure 3 is the infrared spectrum of the waterborne polyurethane prepared in Example 1. DETAILED DESCRIPTION

[0032] The preparation method and application of the present invention are further described in detail below through examples, but are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the polyols, hydrophilic chain extenders and cross-linking agents involved are vacuum dried before use, and the methods involved are all conventional methods.

[0033] Test Method

[0034] Infrared spectrum test: The American ThermoFisher 6700 advanced Fourier transform infrared spectrometer was used to characterize the crosslinking agent structure by potassium bromide tablet method and the polyurethane emulsion structure by thin film method.

[0035] H NMR spectrum: The structure of the cross-linker was characterized using a Bruker Avance II 400 NMR spectrometer from Bruker, Switzerland.

[0036] Mechanical properties: The polyurethane specimens were tested using an American Instron 5567A material testing machine.

[0037] Coating performance: Coating hardness is tested according to GB / T 6739-2006 "Paint and varnish pencil method for determination of paint film hardness". Coating adhesion is tested according to GB / T 9286-1998 "Paint and varnish film cross-cut test". Coating wear resistance is tested according to GB / T 1768-2006 "Determination of wear resistance of paint and varnish by rotating rubber grinding wheel method", using H22S ceramic grinding wheel, 1000g load, and 1000 cycles of testing.

[0038] Example 1

[0039] Add polycarbonate polyol PCDL2000, hydrophilic chain extender DMBA, TDI, 1% dibutyltin dilaurate and butanone to a reactor with stirring and condenser, pass N2 protection, and react at 50°C for 5h. Add crosslinker BBTDA and react for 7h, add butanediol until the isocyanate reacts completely to obtain a polyurethane prepolymer. Cool to 20°C and add a small amount of butanone to adjust the viscosity. Add triethylamine to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion or dispersion and dry it at room temperature for 5 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.4.

[0040] The mass content of 2,2-dihydroxymethylbutyric acid is 3 wt %.

[0041] The amount of triethylamine used is the same as the molar number of the hydrophilic chain extender.

[0042] The molar number of BBTDA is the molar number of the remaining isocyanate groups. The amount of butanone used is 5 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0043] Figure 1 is the infrared spectrum of the cross-linking agent BBTDA used in this example. As can be seen from the figure, 2200cm -1 The characteristic peaks of cyano group disappeared completely, and the peaks at 819 cm -1 The characteristic peak of the triazine ring appears at , which proves that the cyano group on dicyandiamide has been completely reacted to form a triazine ring.

[0044] Figure 2 This is the H NMR spectrum of the crosslinking agent BBTDA used in this example. As can be seen from the figure, 6.56 ppm corresponds to 8 H on the 4 primary amines on the triazine ring; 2.31 ppm corresponds to 4 H on the 2 methylene groups connected to the triazine ring; 1.68-1.55 ppm corresponds to 4 H on the 2 middle methylene groups. Combining the results of infrared spectrum and H NMR spectrum, it can be proved that the bistriazine crosslinking agent BBTDA has been successfully synthesized.

[0045] Figure 3 The infrared spectra of the waterborne polyurethane prepared in this example are shown in Figure 2. -1 There is no characteristic peak of -NCO at 1743cm -1 The peak at 1674 cm is the characteristic peak of the carbonyl group in carbamate, indicating that -NCO in TDI reacts with -OH. By comparing the FT-IR spectra, it can be found that after adding BBTDA, the peak at 1674 cm -1An obvious peak appeared at 1674 cm -1 The characteristic peak at showed an increasing trend, indicating that the -NCO in TDI reacted with the -NH2 in BBTDA to form a urea bond.

[0046] Example 2

[0047] Add polycarbonate polyol PCDL2000, hydrophilic chain extender DMBA, TDI, 1% dibutyltin dilaurate and butanone to a reactor with stirring and condenser, pass N2 protection, and react at 50°C for 5h. Add crosslinker BBTDA and react for 7h, add butanediol until the isocyanate reacts completely to obtain a polyurethane prepolymer. Cool to 20°C and add a small amount of butanone to adjust the viscosity. Add triethylamine to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion or dispersion and dry it at room temperature for 5 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.4.

[0048] The mass content of 2,2-dihydroxymethylbutyric acid is 3 wt %.

[0049] The molar number of BBTDA is the molar number of the remaining isocyanate groups. The amount of butanone used is 5 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0050] Example 3

[0051] Add polyester polyol PCL2000, hydrophilic chain extender DMPA, IPDI, 15% stannous octoate and butanone to a reactor with stirring and condenser, pass N2 protection, and react at 50℃ for 5h. Add crosslinker (Ⅱ, R is C2) and react for 10h, add butanediol until the isocyanate reaction is complete to obtain polyurethane prepolymer. Cool to 20℃, and add a small amount of butanone to adjust the viscosity. Add triethylamine to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion or dispersion and dry it at room temperature for 3 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.2.

[0052] The mass content of 2,2-dihydroxymethylbutyric acid is 10 wt %.

[0053] The molar number of the crosslinking agent is the molar number of the remaining isocyanate groups. The amount of butanone used is 6 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0054] Example 4

[0055] Add polyester polyol PCL2000, hydrophilic chain extender DMPA, IPDI, 1.5% dibutyltin dilaurate and acetone to a reactor with stirring and condenser, pass N2 protection, and react at 60°C for 10 hours. Add BBTDA and react for 5 hours, add propylene glycol until the isocyanate reaction is complete to obtain a polyurethane prepolymer. Cool to 20°C and add a small amount of acetone to adjust the viscosity. Add triethylamine to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion and dry it at room temperature for 3 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.4.

[0056] The mass content of 2,2-dihydroxymethylbutyric acid is 7 wt %.

[0057] The molar number of BBTDA is the molar number of the remaining isocyanate groups. The amount of butanone used is 6 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0058] Example 5

[0059] Add polypropylene glycol PPG, hydrophilic chain extender DMPA, MDI, 4% dibutyltin dilaurate and butanone to a reactor with stirring and condenser, pass N2 protection, and react at 90°C for 2h. Add BBTDA and react for 2h, add butanediol until the isocyanate reacts completely to obtain a polyurethane prepolymer. Cool to 20°C and add a small amount of acetone to adjust the viscosity. Add triethylamine to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion and dry it at room temperature for 3 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.6.

[0060] The mass content of 2,2-dihydroxymethylpropionic acid is 7 wt %.

[0061] The molar number of BBTDA is the molar number of the remaining isocyanate groups. The amount of butanone used is 6 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0062] Example 6

[0063] Add polyester polyol PCL2000, hydrophilic chain extender DMPA, IPDI, 1.5% dibutyltin dilaurate and acetone to a reactor with stirring and condenser, pass N2 protection, and react at 60℃ for 10h. Add crosslinker (Ⅱ, R is C6) and react for 5h, add propylene glycol until the isocyanate reaction is complete to obtain polyurethane prepolymer. Cool to 20℃, and add a small amount of acetone to adjust the viscosity. Add triethylamine to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion and dry it at room temperature for 3 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.4.

[0064] The mass content of 2,2-dihydroxymethylbutyric acid is 7 wt %.

[0065] The molar number of the crosslinking agent is the molar number of the remaining isocyanate groups. The amount of butanone used is 6 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0066] Example 7

[0067] Add polyester polyol PCL2000, hydrophilic chain extender DMBA, HDI, 4% dibutyltin dilaurate and butanone to a reactor with stirring and condenser, pass N2 protection, and react at 50°C for 5h. Add BBTDA and react for 10h, add butanediol until the isocyanate reacts completely to obtain a polyurethane prepolymer. Cool to 20°C and add a small amount of butanone to adjust the viscosity. Add triethylamine to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion and dry it at room temperature for 3 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.8.

[0068] The mass content of 2,2-dihydroxymethylbutyric acid is 3 wt %.

[0069] The molar number of BBTDA is the molar number of the remaining isocyanate groups. The amount of butanone used is 6 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0070] Example 8

[0071] Add polyester polyol PCL2000, hydrophilic chain extender DMBA, HDI, 4% dibutyltin dilaurate and butanone to a reactor with stirring and condenser, pass N2 protection, and react at 60°C for 8h. Add BBTDA and react for 2h, add butanediol until the isocyanate reacts completely to obtain a polyurethane prepolymer. Cool to 20°C and add a small amount of butanone to adjust the viscosity. Add NaOH to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion and dry it at room temperature for 3 days to obtain an aqueous polyurethane coating. Among them, the R value is 2.0.

[0072] The mass content of 2,2-dihydroxymethylbutyric acid is 12 wt %.

[0073] The molar number of BBTDA is the molar number of the remaining isocyanate groups. The amount of butanone used is twice the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0074] Example 9

[0075] Add polycarbonate polyol PCDL1000, hydrophilic chain extender DMPA, TDI, 2% dibutyltin dilaurate and butanone to a reactor with stirring and condenser, pass N2 protection, and react at 70°C for 5h. Add BBTDA and react for 5h, add butanediol until the isocyanate reacts completely to obtain a polyurethane prepolymer. Cool to 20°C and add a small amount of butanone to adjust the viscosity. Add triethylamine to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion and dry it at room temperature for 3 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.4.

[0076] The mass content of 2,2-dihydroxymethylpropionic acid is 10 wt %.

[0077] The molar number of BBTDA is the molar number of the remaining isocyanate groups. The amount of butanone used is 6 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0078] Example 10

[0079] Polyester polyol PCL2000, hydrophilic chain extender DMBA, HDI, 4% dibutyltin dilaurate and butanone were added to a reactor with stirring and condenser, and N2 was passed through to react at 100℃ for 3h. 10) for 8 hours, add butanediol until the isocyanate reaction is complete to obtain a polyurethane prepolymer. Cool to 20°C, and add a small amount of butanone to adjust the viscosity. Add triethylamine for neutralization, cool and add deionized water for rapid stirring and emulsification. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion and dry at room temperature for 3 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.5.

[0080] The mass content of 2,2-dihydroxymethylbutyric acid is 8 wt %.

[0081] The molar number of the crosslinking agent is the molar number of the remaining isocyanate groups. The amount of butanone used is 6 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0082] Embodiment 11

[0083] Add polycarbonate polyol PCDL2000, hydrophilic chain extender DMBA, TDI, 0.1% dibutyltin dilaurate and butanone to a reactor with stirring and condenser, pass N2 protection, and react at 70°C for 3h. Add crosslinker BBTDA and react for 3h, add butanediol until the isocyanate reacts completely to obtain a polyurethane prepolymer. Cool to 30°C and add a small amount of butanone to adjust the viscosity. Add triethylamine to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion and dry it at room temperature for 5 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.1.

[0084] The mass content of 2,2-dihydroxymethylbutyric acid is 6 wt %.

[0085] The molar number of BBTDA is the molar number of the remaining isocyanate groups. The amount of butanone used is 3 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0086] Example 12

[0087] Add polycarbonate polyol PCDL2000, hydrophilic chain extender DMBA, TDI, 1% dibutyltin dilaurate and butanone to a reactor with stirring and condenser, pass N2 protection, and react at 80℃ for 5h. Add crosslinker BBTDA and react for 7h, add butanediol until the isocyanate reacts completely to obtain polyurethane prepolymer. Cool to 20℃ and add a small amount of butanone to adjust the viscosity. Add triethylamine for neutralization, cool and add deionized water for rapid stirring and emulsification. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion and dry it at room temperature for 7 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.2.

[0088] The mass content of 2,2-dihydroxymethylbutyric acid is 4 wt %.

[0089] The molar number of BBTDA is the molar number of the remaining isocyanate groups. The amount of butanone used is 4 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0090] Embodiment 13

[0091] Add polyester polyol PCL2000, hydrophilic chain extender DMBA, HDI, 4% dibutyltin dilaurate and butanone to a reactor with stirring and condenser, pass N2 protection, and react at 80℃ for 10h. Add crosslinker (Ⅱ, R is C6) and react for 7h, add butanediol until the isocyanate reacts completely to obtain polyurethane prepolymer. Cool to 20℃, and add a small amount of butanone to adjust the viscosity. Add triethylamine to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain water-based polyurethane emulsion or dispersion. Apply the water-based polyurethane emulsion and dry it at room temperature for 3 days to obtain a water-based polyurethane coating. Among them, the R value is 1.5.

[0092] The mass content of 2,2-dihydroxymethylbutyric acid is 3 wt %.

[0093] The molar number of the crosslinking agent is the molar number of the remaining isocyanate groups. The amount of butanone used is 1 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0094] Embodiment 14

[0095] Add polyester polyol PCL2000, hydrophilic chain extender DMBA, HDI, 4% dibutyltin dilaurate and butanone to a reactor with stirring and condenser, pass N2 protection, and react at 50°C for 5h. Add BBTDA and react for 10h, add butanediol until the isocyanate reacts completely to obtain a polyurethane prepolymer. Cool to 20°C and add a small amount of butanone to adjust the viscosity. Add triethylamine to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion and dry it at room temperature for 3 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.8.

[0096] The mass content of 2,2-dihydroxymethylbutyric acid is 10 wt %.

[0097] The amount of triethylamine used is the same as the molar number of the hydrophilic chain extender.

[0098] The molar number of BBTDA is the molar number of the remaining isocyanate groups. The amount of butanone used is 6 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0099] Embodiment 15

[0100] Add polyester polyol PCL1000, hydrophilic chain extender DMPA, IPDI, 5% dibutyltin dilaurate and acetone to a reactor with stirring and condenser, pass N2 protection, and react at 90°C for 1h. Add BBTDA and react for 6h, add butanediol until the isocyanate reacts completely to obtain a polyurethane prepolymer. Cool to 20°C and add a small amount of butanone to adjust the viscosity. Add triethylamine to neutralize, cool and add deionized water to stir and emulsify quickly. Remove butanone by vacuum distillation to obtain an aqueous polyurethane emulsion or dispersion. Apply the aqueous polyurethane emulsion and dry it at room temperature for 3 days to obtain an aqueous polyurethane coating. Among them, the R value is 1.6.

[0101] The mass content of 2,2-dihydroxymethylbutyric acid is 8 wt %.

[0102] The amount of triethylamine used is the same as the molar number of the hydrophilic chain extender.

[0103] The molar number of BBTDA is the molar number of the remaining isocyanate groups. The amount of butanone used is 6 times the total mass of all the reaction raw materials, and the amount of deionized water used depends on the dispersion of the emulsion.

[0104] After the coating of the aqueous polyurethane emulsion prepared in the example was dried, performance tests were performed. The results are shown in Table 1.

[0105] Table 1 Properties of high wear-resistant waterborne polyurethane coating

[0106]

[0107]

[0108] In summary, the embodiments of the present invention prepare a highly wear-resistant one-component waterborne polyurethane and its emulsion or dispersion. Compared with the commonly used one-component waterborne polyurethane, the present invention introduces a ditriazine structure into the polyurethane structure, and significantly improves the wear resistance, hardness and mechanical properties of the coating by introducing rigid groups and constructing chemical and physical cross-linking networks. The test results show that the one-component waterborne polyurethane coating prepared by the present invention has excellent comprehensive properties and therefore has a wide range of applications.

[0109] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations and simplifications that deviate from the essence and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A highly wear-resistant one-component waterborne polyurethane, characterized in that: The polyurethane molecular chain contains the following structure: Where R is C 1～10 Alkyl, C 6～10 Alicyclic group, C 6～10 One or more aromatic hydrocarbon groups; A is a residue structure of diisocyanate without -NCO group; B is a residue structure of polyester polyol, polyether polyol or polycarbonate polyol without -OH.

2. The method for preparing a highly wear-resistant one-component aqueous polyurethane dispersion according to claim 1, characterized in that: The following steps are involved: According to the proportion, polyol, hydrophilic chain extender, diisocyanate, catalyst and solvent are added to a reaction kettle with stirring and condenser, and N2 or other inert gas is passed through for protection, and the reaction is carried out at 50-100° C. for 2-15 hours; a crosslinking agent and a small molecule diol are added and the reaction is carried out at 50-100° C. for 2-15 hours to obtain a polyurethane prepolymer; Then, the prepolymer is cooled to 15-40° C., and a small amount of solvent is added to adjust the viscosity; a neutralizing agent is added for neutralization, and water is added for emulsification, and the solvent is removed by vacuum distillation to obtain an aqueous polyurethane dispersion.

3. The method for preparing a highly wear-resistant one-component aqueous polyurethane dispersion according to claim 2, characterized in that: The diisocyanate is one or a mixture of two or more of toluene diisocyanate TDI, hexamethylene diisocyanate HDI, diphenylmethane diisocyanate MDI, and isophorone diisocyanate IPDI, and the molar ratio of the isocyanate group to the hydroxyl group is 1.0-2.0; The polyol is one or a mixture of two or more of polyester polyol, polyether polyol, polycarbonate polyol and polypropylene glycol PPG; the molecular weight of the polyol is 1000-3000 g / mol; The hydrophilic chain extender is one or a mixture of 2,2-dihydroxymethyl propionic acid DMPA and 2,2-dihydroxymethyl butyric acid DMBA, and the mass content of the hydrophilic chain extender is 1.5-15wt% of all the reaction raw materials; The catalyst is one or both of stannous octoate and dibutyltin dilaurate, and the mass ratio of the catalyst to the polyol is 0.1-10wt%; The crosslinking agent is 6,6'-(1,4-butane)bis(1,3,5-triazine-2,4-diamine); the number of moles of the crosslinking agent is the number of moles of the remaining isocyanate groups; The small molecule diol is one or a mixture of two or more of ethylene glycol, propylene glycol and butanediol; The solvent is one or a mixture of two or more of acetone, butanone, ethylene glycol methyl ether, and trifluoroacetic acid, and the amount of the solvent used at the beginning of the reaction is 1-8 times the total mass of all the reaction raw materials; The neutralizing agent is one or both of triethylamine and NaOH.

4. The method for preparing a highly wear-resistant one-component aqueous polyurethane dispersion according to claim 3, characterized in that: The polyol is a polyester polyol or a polycarbonate polyol; The molecular weight of the polyol is 1000 to 2000 g / mol; The small molecule diol is one of ethylene glycol, propylene glycol and butanediol or a mixture of two or more thereof.

5. The method for preparing a highly wear-resistant one-component aqueous polyurethane dispersion according to claim 4, characterized in that: The molecular weight of the polyol is 1000 g / mol or 2000 g / mol.

6. A method for preparing a highly wear-resistant one-component waterborne polyurethane coating, characterized in that: The single-component waterborne polyurethane dispersion prepared by the method for preparing a highly wear-resistant single-component waterborne polyurethane dispersion according to any one of claims 2 to 5 is coated, dried and solidified to obtain a single-component waterborne polyurethane coating.

7. The method for preparing the highly wear-resistant one-component waterborne polyurethane dispersion according to any one of claims 2 to 5 is used as a coating or adhesive in the fields of automobiles, electronic appliances, engineering machinery, leather finishing, chemicals and wood products.

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