Preparation method of polymeric dispersant

Abstract

The invention provides a preparation method of a polymeric dispersant, which comprises the following steps: (1) under the protection of nitrogen, mixing 10 parts by mass of diisocyanate, 6-8 parts by mass of mixed dihydric alcohol and 600-700 parts by mass of dimethylformamide, heating to 78-80 DEG C, and reacting for 80-100 minutes to obtain a product A; (2) after the reaction is finished, cooling the product A to 68-72 DEG C, dropwise adding a dimethylformamide solution of dimethylolpropionic acid, adding an organic tin catalyst after dropwise adding is finished, and reacting for 90-100 minutes to obtain a product B; and (3) dropwise adding a hydrophilic carboxyl dihydric alcohol solution into the product B, blocking, adding water to adjust the solid content of the system to 32-35%, heating to 64-67 DEG C, adding a modified filler, and continuously stirring and dissolving for 40-50 minutes to obtain the polymeric dispersant. The polymeric dispersant provided by the invention can improve the dispersion stability of the ink pigment.

Description

Technical Field

[0001] The invention belongs to the technical field of dispersants, and in particular relates to a method for preparing a polymer dispersant. Background Art

[0002] Polymer dispersants are a class of chemicals widely used in many industrial fields. They are mainly used to improve the dispersion of particles in liquid media, prevent particle aggregation, and improve product stability and performance. These dispersants can be used in coatings, printing inks, plastics, ceramics, papermaking, agricultural chemicals, cosmetics and other industries.

[0003] Polymer dispersants are important for the dispersion of ceramic pigments in ceramic inks because they can significantly improve the dispersion and stability of pigments, thereby improving the quality and performance of the final product. Polymer dispersants are important in ceramic inks: Improve pigment dispersion: Polymer dispersants can prevent pigment particles from aggregating through electrostatic repulsion and steric hindrance, thereby ensuring uniform distribution of pigments and avoiding precipitation and agglomeration. Enhance ink stability: By stabilizing pigment particles, polymer dispersants can extend the shelf life of ceramic inks and ensure the uniformity and fluidity of inks over a long period of time. Improve printing performance: Well-dispersed pigment particles help achieve finer printing resolution, reduce the risk of nozzle clogging, and increase printing speed and pattern clarity. Improve finished product quality: Uniform pigment dispersion ensures color consistency and vividness, while improving the surface smoothness and gloss of ceramic products. Cost savings: By reducing the amount of pigment used and improving grinding efficiency, polymer dispersants can reduce production costs while reducing energy consumption and labor requirements.

[0004] However, the application of polymer dispersants in ceramic inks also has some technical defects: Cost issues: High-performance polymer dispersants are often more expensive, which may increase the overall cost for large-scale industrial production. Compatibility limitations: Some polymer dispersants may be incompatible with certain types of pigments or solvents, affecting the dispersion effect or causing other chemical reactions. Residue issues: During the sintering process, some polymer dispersants may remain, affecting the physical and chemical properties of the finished product, such as reducing hardness or changing color. Environmental and safety issues: The synthesis and use of some polymer dispersants may involve harmful substances, posing a potential threat to the environment and human health. Complexity: The selection and optimization of polymer dispersants requires in-depth chemical knowledge and experience to match specific pigments and production processes, which increases the complexity of R&D and production. Poor dispersion stability: The dispersion rate is low over time, affecting the use effect. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a polymer dispersant.

[0006] In order to achieve the above object, the present invention provides the following technical solutions: A method for preparing a polymer dispersant, the method comprising the following steps: (1) Under the protection of nitrogen, 10 parts by weight of diisocyanate, 7 parts by weight of mixed diol and 650 parts by weight of dimethylformamide were mixed, and the temperature was raised to 79° C. and reacted for 90 minutes to obtain product A; (2) After the reaction is completed, the product A is cooled to 70°C, and a dimethylformamide solution of dimethylolpropionic acid is added dropwise. After the addition is complete, an organic tin catalyst is added and the reaction is carried out for 95 minutes to obtain the product B; (3) Add a hydrophilic carboxyl diol solution to product B for end-capping, the reaction time is 150 min, the reaction temperature is 79°C; cool to 54°C, slowly add a 20 wt% sodium carbonate solution, then add water to adjust the solid content of the system to 34%, raise the temperature to 65°C, add the modified filler, continue stirring and dissolving for 45 min, and obtain a polymer dispersant.

[0007] The diisocyanate is a mixture of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate in a mass ratio of 1:1.3-1.6:0.5-0.8.

[0008] Furthermore, the mixed diol is a mixture of hydroquinone, bisphenol A and pentanediol in a mass ratio of 1.4-1.8:1:0.2-0.6.

[0009] Furthermore, the organic tin catalyst is dibutyltin dilaurate.

[0010] Furthermore, the mass of the organotin catalyst accounts for 0.1-0.2 wt % of the total mass of the diisocyanate and the mixed diol.

[0011] Furthermore, the concentration of the dimethylformamide solution of dimethylolpropionic acid is 20wt%-25wt%, and the total mass ratio of dimethylolpropionic acid to diisocyanate and mixed diol is 1:10-20.

[0012] Furthermore, the mass of the modified filler accounts for 10-14% of the total mass of the diisocyanate and the mixed diol.

[0013] Furthermore, the preparation method of the modified filler is: (1) Mixing kaolin, silicon dioxide and calcium carbonate in a mass ratio of 0.3-0.8:1.4-1.7:1 to obtain a mixed filler; (2) Mix silica, 60-70wt% ethanol aqueous solution and silane coupling agent KH550 in a mass ratio of 1:12-15:0.02-0.05, stir and react at 62-65°C for 2-4h, filter and obtain a solid, wash and dry it to obtain a modified filler.

[0014] Furthermore, the particle size of the kaolin is 100-200 mesh, the particle size of the silicon dioxide is 50-100 nm, and the particle size of the calcium carbonate is 300-500 nm.

[0015] The invention provides a polymer dispersant prepared by the preparation method.

[0016] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: the present invention mixes diisocyanates (TDI, MDI, IPDI) and polyols (hydroquinone, bisphenol A, pentanediol) as reaction raw materials, so that different functional groups and structural units appear in the polymer chain, and the differentiated structural units can form more complex interactions with the pigment surface, thereby improving the dispersibility and stability of the pigment. The modified filler is surface treated to form a stronger interaction with the polymer dispersant and ink pigment. This enhanced compatibility helps the pigment to be better dispersed in the system and reduce agglomeration. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Example 1 This embodiment provides a method for preparing a polymer dispersant, and the preparation method comprises the following steps: (1) Under the protection of nitrogen, 10 parts by weight of diisocyanate, 7 parts by weight of mixed diol and 650 parts by weight of dimethylformamide were mixed, and the temperature was raised to 79° C. and reacted for 90 minutes to obtain product A; (2) After the reaction is completed, the product A is cooled to 70°C, and a dimethylformamide solution of dimethylolpropionic acid is added dropwise. After the addition is complete, an organic tin catalyst is added and the reaction is carried out for 95 minutes to obtain the product B; (3) Add a hydrophilic carboxyl diol solution to product B for end-capping, the reaction time is 150 min, the reaction temperature is 79°C; cool to 54°C, slowly add a 20 wt% sodium carbonate solution, then add water to adjust the solid content of the system to 34%, raise the temperature to 65°C, add the modified filler, continue stirring and dissolving for 45 min, and obtain a polymer dispersant.

[0019] The diisocyanate is a mixture of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate in a mass ratio of 1:1.5:0.7.

[0020] The mixed diol is a mixture of hydroquinone, bisphenol A and pentanediol in a mass ratio of 1.6:1:0.4.

[0021] The organotin catalyst is dibutyltin dilaurate.

[0022] The mass of the organotin catalyst accounts for 0.15wt% of the total mass of the diisocyanate and the mixed diol.

[0023] The concentration of the dimethylformamide solution of dimethylolpropionic acid is 23 wt %, and the total mass ratio of dimethylolpropionic acid to diisocyanate and mixed diol is 1:15.

[0024] The mass of the modified filler accounts for 12% of the total mass of the diisocyanate and the mixed diol.

[0025] The preparation method of the modified filler is: (1) kaolin, silicon dioxide and calcium carbonate are mixed in a mass ratio of 0.4:1.5:1 to obtain a mixed filler; (2) Mix silica, 65 wt% ethanol aqueous solution and silane coupling agent KH550 in a mass ratio of 1:13:0.04, stir and react at 64°C for 3 h, filter and obtain a solid, wash and dry it to obtain a modified filler.

[0026] The particle size of the kaolin is 100-200 meshes, the particle size of the silicon dioxide is 50-100 nm, and the particle size of the calcium carbonate is 300-500 nm.

[0027] Example 2 This embodiment provides a method for preparing a polymer dispersant, and the preparation method comprises the following steps: (1) Under the protection of nitrogen, 10 parts by weight of diisocyanate, 6 parts by weight of mixed diol and 600 parts by weight of dimethylformamide were mixed, and the temperature was raised to 78° C. and reacted for 80 minutes to obtain product A; (2) After the reaction is completed, the product A is cooled to 68°C, and a dimethylformamide solution of dimethylolpropionic acid is added dropwise. After the addition is complete, an organic tin catalyst is added and the reaction is carried out for 90 minutes to obtain the product B; (3) Add a hydrophilic carboxyl diol solution to product B for end-capping, the reaction time is 140 min, the reaction temperature is 78°C; cool to 52°C, slowly add a 10 wt% sodium carbonate solution, then add water to adjust the solid content of the system to 32%, raise the temperature to 64°C, add the modified filler, continue stirring and dissolving for 40 min, and obtain a polymer dispersant.

[0028] The diisocyanate is a mixture of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate in a mass ratio of 1:1.3:0.5.

[0029] The mixed diol is a mixture of hydroquinone, bisphenol A and pentanediol in a mass ratio of 1.4:1:0.2.

[0030] The organotin catalyst is dibutyltin dilaurate.

[0031] The mass of the organic tin catalyst accounts for 0.1 wt % of the total mass of the diisocyanate and the mixed diol.

[0032] The concentration of the dimethylformamide solution of dimethylolpropionic acid is 20 wt %, and the total mass ratio of dimethylolpropionic acid to diisocyanate and mixed diol is 1:10.

[0033] The mass of the modified filler accounts for 10% of the total mass of the diisocyanate and the mixed diol.

[0034] The preparation method of the modified filler is: (1) Mixing kaolin, silicon dioxide and calcium carbonate in a mass ratio of 0.3:1.4:1 to obtain a mixed filler; (2) Silicon dioxide, 60 wt% ethanol aqueous solution and silane coupling agent KH550 were mixed in a mass ratio of 1:12:0.02, stirred at 62°C for 2 h, filtered to obtain a solid, washed and dried to obtain a modified filler.

[0035] The particle size of the kaolin is 100-200 meshes, the particle size of the silicon dioxide is 50-100 nm, and the particle size of the calcium carbonate is 300-500 nm.

[0036] Example 3 This embodiment provides a method for preparing a polymer dispersant, and the preparation method comprises the following steps: (1) Under the protection of nitrogen, 10 parts by weight of diisocyanate, 8 parts by weight of mixed diol and 700 parts by weight of dimethylformamide were mixed, the temperature was raised to 80° C. and the reaction was carried out for 100 minutes to obtain product A; (2) After the reaction is completed, the product A is cooled to 72°C, and a dimethylformamide solution of dimethylolpropionic acid is added dropwise. After the addition is complete, an organic tin catalyst is added and the reaction is continued for 100 minutes to obtain the product B; (3) Add a hydrophilic carboxyl diol solution to product B for end-capping, the reaction time is 160 min, the reaction temperature is 80°C; cool to 55°C, slowly add a 30 wt% sodium carbonate solution, then add water to adjust the solid content of the system to 35%, raise the temperature to 67°C, add the modified filler, continue stirring and dissolving for 50 min, and obtain a polymer dispersant.

[0037] The diisocyanate is a mixture of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate in a mass ratio of 1:1.6:0.8.

[0038] The mixed diol is a mixture of hydroquinone, bisphenol A and pentanediol in a mass ratio of 1.8:1:0.6.

[0039] The organotin catalyst is dibutyltin dilaurate.

[0040] The mass of the organotin catalyst accounts for 0.2 wt % of the total mass of the diisocyanate and the mixed diol.

[0041] The concentration of the dimethylformamide solution of dimethylolpropionic acid is 25 wt %, and the total mass ratio of dimethylolpropionic acid to diisocyanate and mixed diol is 1:20.

[0042] The mass of the modified filler accounts for 14% of the total mass of the diisocyanate and the mixed diol.

[0043] The preparation method of the modified filler is: (1) kaolin, silicon dioxide and calcium carbonate are mixed in a mass ratio of 0.8:1.7:1 to obtain a mixed filler; (2) Mix silica, 70 wt% ethanol aqueous solution and silane coupling agent KH550 in a mass ratio of 1:15:0.05, stir and react at 65°C for 4 hours, filter and obtain a solid, wash and dry it to obtain a modified filler.

[0044] The particle size of the kaolin is 100-200 meshes, the particle size of the silicon dioxide is 50-100 nm, and the particle size of the calcium carbonate is 300-500 nm.

[0045] Comparative Example 1 The difference between this comparative example and Example 1 is that the composition of the diisocyanate is different.

[0046] A method for preparing a polymer dispersant, the method comprising the following steps: (1) Under the protection of nitrogen, 10 parts by weight of diisocyanate, 7 parts by weight of mixed diol and 650 parts by weight of dimethylformamide were mixed, and the temperature was raised to 79° C. and reacted for 90 minutes to obtain product A; (2) After the reaction is completed, the product A is cooled to 70°C, and a dimethylformamide solution of dimethylolpropionic acid is added dropwise. After the addition is complete, an organic tin catalyst is added and the reaction is carried out for 95 minutes to obtain the product B; (3) Add a hydrophilic carboxyl diol solution to product B for end-capping, the reaction time is 150 min, the reaction temperature is 79°C; cool to 54°C, slowly add a 20 wt% sodium carbonate solution, then add water to adjust the solid content of the system to 34%, raise the temperature to 65°C, add the modified filler, continue stirring and dissolving for 45 min, and obtain a polymer dispersant.

[0047] The diisocyanate is a mixture of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate in a mass ratio of 1:1:1.

[0048] The mixed diol is a mixture of hydroquinone, bisphenol A and pentanediol in a mass ratio of 1.6:1:0.4.

[0049] The organotin catalyst is dibutyltin dilaurate.

[0050] The mass of the organotin catalyst accounts for 0.15wt% of the total mass of the diisocyanate and the mixed diol.

[0051] The concentration of the dimethylformamide solution of dimethylolpropionic acid is 23 wt %, and the total mass ratio of dimethylolpropionic acid to diisocyanate and mixed diol is 1:15.

[0052] The mass of the modified filler accounts for 12% of the total mass of the diisocyanate and the mixed diol.

[0053] The preparation method of the modified filler is: (1) kaolin, silicon dioxide and calcium carbonate are mixed in a mass ratio of 0.4:1.5:1 to obtain a mixed filler; (2) Mix silica, 65 wt% ethanol aqueous solution and silane coupling agent KH550 in a mass ratio of 1:13:0.04, stir and react at 64°C for 3 h, filter and obtain a solid, wash and dry it to obtain a modified filler.

[0054] The particle size of the kaolin is 100-200 meshes, the particle size of the silicon dioxide is 50-100 nm, and the particle size of the calcium carbonate is 300-500 nm.

[0055] Comparative Example 2 The difference between this comparative example and Example 1 is that the composition of the mixed diol is different.

[0056] A method for preparing a polymer dispersant, the method comprising the following steps: (1) Under the protection of nitrogen, 10 parts by weight of diisocyanate, 7 parts by weight of mixed diol and 650 parts by weight of dimethylformamide were mixed, and the temperature was raised to 79° C. and reacted for 90 minutes to obtain product A; (2) After the reaction is completed, the product A is cooled to 70°C, and a dimethylformamide solution of dimethylolpropionic acid is added dropwise. After the addition is complete, an organic tin catalyst is added and the reaction is carried out for 95 minutes to obtain the product B; (3) Add a hydrophilic carboxyl diol solution to product B for end-capping, the reaction time is 150 min, the reaction temperature is 79°C; cool to 54°C, slowly add a 20 wt% sodium carbonate solution, then add water to adjust the solid content of the system to 34%, raise the temperature to 65°C, add the modified filler, continue stirring and dissolving for 45 min, and obtain a polymer dispersant.

[0057] The diisocyanate is a mixture of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate in a mass ratio of 1:1.5:0.7.

[0058] The mixed diol is a mixture of hydroquinone, bisphenol A and pentanediol in a mass ratio of 1:1:1.

[0059] The organotin catalyst is dibutyltin dilaurate.

[0060] The mass of the organotin catalyst accounts for 0.15wt% of the total mass of the diisocyanate and the mixed diol.

[0061] The concentration of the dimethylformamide solution of dimethylolpropionic acid is 23 wt %, and the total mass ratio of dimethylolpropionic acid to diisocyanate and mixed diol is 1:15.

[0062] The mass of the modified filler accounts for 12% of the total mass of the diisocyanate and the mixed diol.

[0063] The preparation method of the modified filler is: (1) kaolin, silicon dioxide and calcium carbonate are mixed in a mass ratio of 0.4:1.5:1 to obtain a mixed filler; (2) Mix silica, 65 wt% ethanol aqueous solution and silane coupling agent KH550 in a mass ratio of 1:13:0.04, stir and react at 64°C for 3 h, filter and obtain a solid, wash and dry it to obtain a modified filler.

[0064] The particle size of the kaolin is 100-200 meshes, the particle size of the silicon dioxide is 50-100 nm, and the particle size of the calcium carbonate is 300-500 nm.

[0065] Comparative Example 3 The difference between this comparative example and Example 1 is that the ratios of kaolin, silicon dioxide and calcium carbonate are different.

[0066] A method for preparing a polymer dispersant, the method comprising the following steps: (1) Under the protection of nitrogen, 10 parts by weight of diisocyanate, 7 parts by weight of mixed diol and 650 parts by weight of dimethylformamide were mixed, and the temperature was raised to 79° C. and reacted for 90 minutes to obtain product A; (2) After the reaction is completed, the product A is cooled to 70°C, and a dimethylformamide solution of dimethylolpropionic acid is added dropwise. After the addition is complete, an organic tin catalyst is added and the reaction is carried out for 95 minutes to obtain the product B; (3) Add a hydrophilic carboxyl diol solution to product B for end-capping, the reaction time is 150 min, the reaction temperature is 79°C; cool to 54°C, slowly add a 20 wt% sodium carbonate solution, then add water to adjust the solid content of the system to 34%, raise the temperature to 65°C, add the modified filler, continue stirring and dissolving for 45 min, and obtain a polymer dispersant.

[0067] The diisocyanate is a mixture of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate in a mass ratio of 1:1.5:0.7.

[0068] The mixed diol is a mixture of hydroquinone, bisphenol A and pentanediol in a mass ratio of 1.6:1:0.4.

[0069] The organotin catalyst is dibutyltin dilaurate.

[0070] The mass of the organotin catalyst accounts for 0.15wt% of the total mass of the diisocyanate and the mixed diol.

[0071] The concentration of the dimethylformamide solution of dimethylolpropionic acid is 23 wt %, and the total mass ratio of dimethylolpropionic acid to diisocyanate and mixed diol is 1:15.

[0072] The mass of the modified filler accounts for 12% of the total mass of the diisocyanate and the mixed diol.

[0073] The preparation method of the modified filler is: (1) Mixing kaolin, silicon dioxide and calcium carbonate in a mass ratio of 1:1:1 to obtain a mixed filler; (2) Mix silica, 65 wt% ethanol aqueous solution and silane coupling agent KH550 in a mass ratio of 1:13:0.04, stir and react at 64°C for 3 h, filter and obtain a solid, wash and dry it to obtain a modified filler.

[0074] The particle size of the kaolin is 100-200 meshes, the particle size of the silicon dioxide is 50-100 nm, and the particle size of the calcium carbonate is 300-500 nm.

[0075] Comparative Example 4 The difference between this comparative example and Example 1 is that the particle sizes of kaolin, silicon dioxide and calcium carbonate are different.

[0076] A method for preparing a polymer dispersant, the method comprising the following steps: (1) Under the protection of nitrogen, 10 parts by weight of diisocyanate, 7 parts by weight of mixed diol and 650 parts by weight of dimethylformamide were mixed, and the temperature was raised to 79° C. and reacted for 90 minutes to obtain product A; (2) After the reaction is completed, the product A is cooled to 70°C, and a dimethylformamide solution of dimethylolpropionic acid is added dropwise. After the addition is complete, an organic tin catalyst is added and the reaction is carried out for 95 minutes to obtain the product B; (3) Add a hydrophilic carboxyl diol solution to product B for end-capping, the reaction time is 150 min, the reaction temperature is 79°C; cool to 54°C, slowly add a 20 wt% sodium carbonate solution, then add water to adjust the solid content of the system to 34%, raise the temperature to 65°C, add the modified filler, continue stirring and dissolving for 45 min, and obtain a polymer dispersant.

[0077] The diisocyanate is a mixture of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate in a mass ratio of 1:1.5:0.7.

[0078] The mixed diol is a mixture of hydroquinone, bisphenol A and pentanediol in a mass ratio of 1.6:1:0.4.

[0079] The organotin catalyst is dibutyltin dilaurate.

[0080] The mass of the organotin catalyst accounts for 0.15wt% of the total mass of the diisocyanate and the mixed diol.

[0081] The concentration of the dimethylformamide solution of dimethylolpropionic acid is 23 wt %, and the total mass ratio of dimethylolpropionic acid to diisocyanate and mixed diol is 1:15.

[0082] The mass of the modified filler accounts for 12% of the total mass of the diisocyanate and the mixed diol.

[0083] The preparation method of the modified filler is: (1) kaolin, silicon dioxide and calcium carbonate are mixed in a mass ratio of 0.4:1.5:1 to obtain a mixed filler; (2) Mix silica, 65 wt% ethanol aqueous solution and silane coupling agent KH550 in a mass ratio of 1:13:0.04, stir and react at 64°C for 3 h, filter and obtain a solid, wash and dry it to obtain a modified filler.

[0084] The particle size of the kaolin is 60-80 mesh, the particle size of the silicon dioxide is 200-400 nm, and the particle size of the calcium carbonate is 500-800 nm.

[0085] Comparative Example 5 The difference between this comparative example and Example 1 is that kaolin, silicon dioxide and calcium carbonate are replaced by diatomaceous earth, aluminum oxide and titanium dioxide.

[0086] A method for preparing a polymer dispersant, the method comprising the following steps: (1) Under the protection of nitrogen, 10 parts by weight of diisocyanate, 7 parts by weight of mixed diol and 650 parts by weight of dimethylformamide were mixed, and the temperature was raised to 79° C. and reacted for 90 minutes to obtain product A; (2) After the reaction is completed, the product A is cooled to 70°C, and a dimethylformamide solution of dimethylolpropionic acid is added dropwise. After the addition is complete, an organic tin catalyst is added and the reaction is carried out for 95 minutes to obtain the product B; (3) Add a hydrophilic carboxyl diol solution to product B for end-capping, the reaction time is 150 min, the reaction temperature is 79°C; cool to 54°C, slowly add a 20 wt% sodium carbonate solution, then add water to adjust the solid content of the system to 34%, raise the temperature to 65°C, add the modified filler, continue stirring and dissolving for 45 min, and obtain a polymer dispersant.

[0087] The diisocyanate is a mixture of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate in a mass ratio of 1:1.5:0.7.

[0088] The mixed diol is a mixture of hydroquinone, bisphenol A and pentanediol in a mass ratio of 1.6:1:0.4.

[0089] The organotin catalyst is dibutyltin dilaurate.

[0090] The mass of the organotin catalyst accounts for 0.15wt% of the total mass of the diisocyanate and the mixed diol.

[0091] The concentration of the dimethylformamide solution of dimethylolpropionic acid is 23 wt %, and the total mass ratio of dimethylolpropionic acid to diisocyanate and mixed diol is 1:15.

[0092] The mass of the modified filler accounts for 12% of the total mass of the diisocyanate and the mixed diol.

[0093] The preparation method of the modified filler is: (1) diatomaceous earth, alumina and titanium dioxide are mixed in a mass ratio of 0.4:1.5:1 to obtain a mixed filler; (2) Mix silica, 65 wt% ethanol aqueous solution and silane coupling agent KH550 in a mass ratio of 1:13:0.04, stir and react at 64°C for 3 h, filter and obtain a solid, wash and dry it to obtain a modified filler.

[0094] The particle size of the diatomaceous earth is 100-200 meshes, the particle size of the aluminum oxide is 50-100 nm, and the particle size of the titanium dioxide is 300-500 nm.

[0095] Performance Testing 40 g of commercially available ceramic pigment was added to a container, and then 58 g of an organic solvent and 2 g of a polymer dispersant prepared in the examples and comparative examples were added. After mixing evenly, the dispersion stability of the system was tested using a 25 mL ground-mouth colorimetric tube. The test results are shown in Table 1.

[0096] Table 1 Effect of polymer dispersant on dispersion stability of ceramic pigment particles

[0097] It can be seen from the above performance test results that the dispersants of Examples 1-2 have good dispersing effects, especially Example 1 has the most outstanding comprehensive performance, the dispersion system is stable, and the shelf life of the ceramic ink can be extended.

[0098] However, the comparative example does not adopt the necessary technical solution, resulting in its performance being significantly worse than that of the embodiment in the corresponding performance test. The above experimental results further prove the importance of the technical solution defined in the present invention to its technical effect.

[0099] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a polymer dispersant, characterized in that: The preparation method comprises the following steps: (1) Under the protection of nitrogen, 10 parts by weight of diisocyanate, 6-8 parts by weight of mixed diol and 600-700 parts by weight of dimethylformamide were mixed, the temperature was raised to 78-80° C. and the reaction was carried out for 80-100 minutes to obtain product A; (2) After the reaction is completed, the product A is cooled to 68-72°C, and a dimethylformamide solution of dimethylolpropionic acid is added dropwise. After the addition is complete, an organic tin catalyst is added and the reaction is carried out for 90-100 minutes to obtain the product B; (3) Add a hydrophilic carboxyl diol solution to product B for end-capping, the reaction time is 140-160 min, and the reaction temperature is 78-80°C; cool to 52-55°C, slowly add a 10-30wt% sodium carbonate solution, then add water to adjust the solid content of the system to 32-35%, raise the temperature to 64-67°C, add a modified filler, continue stirring and dissolving for 40-50 min, and obtain a polymer dispersant.

2. The method for preparing a polymer dispersant according to claim 1, characterized in that: The diisocyanate is selected from toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate or a mixture of the two or more thereof.

3. The method for preparing a polymer dispersant according to claim 1, characterized in that: The diisocyanate is a mixture of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate in a mass ratio of 1:1.3-1.6:0.5-0.

8.

4. The method for preparing a polymer dispersant according to claim 1, characterized in that: The mixed diol is a mixture of hydroquinone, bisphenol A and pentanediol in a mass ratio of 1.4-1.8:1:0.2-0.

6.

5. The method for preparing a polymer dispersant according to claim 1, characterized in that: The organic tin catalyst is dibutyltin dilaurate, and the mass of the organic tin catalyst accounts for 0.1-0.2wt% of the total mass of the diisocyanate and the mixed diol.

6. The method for preparing a polymer dispersant according to claim 1, characterized in that: The concentration of the dimethylformamide solution of dimethylolpropionic acid is 20wt%-25wt%, and the total mass ratio of dimethylolpropionic acid to diisocyanate and mixed diol is 1:10-20.

7. The method for preparing a polymer dispersant according to claim 1, characterized in that: The mass of the modified filler accounts for 10-14% of the total mass of the diisocyanate and the mixed diol.

8. The method for preparing a polymer dispersant according to claim 7, characterized in that: The preparation method of the modified filler is: (1) Mixing kaolin, silicon dioxide and calcium carbonate in a mass ratio of 0.3-0.8:1.4-1.7:1 to obtain a mixed filler; (2) Mix silica, 60-70wt% ethanol aqueous solution and silane coupling agent KH550 in a mass ratio of 1:12-15:0.02-0.05, stir and react at 62-65°C for 2-4h, filter and obtain a solid, wash and dry it to obtain a modified filler.

9. The method for preparing a polymer dispersant according to claim 8, characterized in that: The particle size of the kaolin is 100-200 meshes, the particle size of the silicon dioxide is 50-100 nm, and the particle size of the calcium carbonate is 300-500 nm.

10. A polymer dispersant prepared according to the preparation method according to any one of claims 1 to 9.

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