Polymer pigment as well as emulsion and preparation method thereof

Abstract

The invention discloses a polymer pigment and an emulsion and a preparation method thereof, methoxyl of pigment red 146 is modified into phenolic hydroxyl through a chemical modification method, and the phenolic hydroxyl is polymerized into matrix resin through a chemical grafting means, so that the color development function of micromolecular pigments and dyes can be combined with the safety and high resistance of macromolecular polymers, and the color development effect is good. The macromolecular polymer coloring agent with high glossiness, good stability, good adhesive force and excellent water resistance is obtained.

Description

Technical Field

[0001] The invention relates to a pigment and a preparation method thereof, in particular to a polymer pigment and an emulsion thereof and a preparation method thereof. Background Art

[0002] At present, the global dye and pigment market is large, reaching a scale of nearly US$50 billion per year. The market capacity of related coating fields such as paints, inks, nail polishes, hair dyes and special coatings is more than US$150 billion per year. However, the existing dye and pigment industry still has many problems such as environmental protection, safety and durability. First, a large amount of color and dye wastewater will be generated in the process of dye and pigment production, leading to water pollution. Secondly, many colors and dyes pose safety hazards to the human body. For example, phenylenediamine hair dyes have strong carcinogenicity, allergic properties (contact dermatitis, asthma), and eczema. Azo dyes, which are the most common type at present, are easy to decompose into carcinogenic aromatic amines under certain conditions. Furthermore, many colors and dyes are easy to be oxidized and decomposed due to their small molecular weight, resulting in limited light fastness. Since dyes and pigments are mostly powder materials, they are easy to produce granularity in sprayed and printed products due to poor dispersion during application, affecting the appearance of the product. If the color development function of small molecule colors and dyes can be combined with the safety and high durability of macromolecular polymers, it is expected to solve many of the above disadvantages. Summary of the invention

[0003] In view of the defects of the prior art, the present invention provides a polymer macromolecular pigment and a preparation method thereof, which combines the color development function of small molecule pigments and dyes with the safety and high tolerance of macromolecular polymers, and successfully prepares a polymer pigment with a large molecular weight, high stability, small particle size and easy dispersion. The particle size of the pigment is smaller than that of conventional preparation methods, and it is stable and not easy to stratify. The pigment is evenly dispersed in the polymer pigment emulsion, and there is no granular feeling when sprayed.

[0004] One of the technical solutions of the present invention is to provide a method for preparing a polymer pigment, which is to modify the methoxyl group of 146 red into phenolic hydroxyl group by chemical modification, and polymerize it into the main resin by chemical grafting, so as to combine the color development function of small molecule pigments and dyes with the safety and high tolerance of macromolecular polymers, and has the following steps: (1) 90-120 parts by weight of polyol A, 3-5 parts by weight of polyol B and 2-4 parts by weight of polyol C are heated to 60-70°C and vacuum dehydrated for 1-1.5 hours under stirring at 250-450 rpm; (2) adding 30-54 parts by weight of polyisocyanate and 0.05-0.058 parts by weight of catalyst, reacting at 80-85° C. for 2-2.5 hours to obtain a primary polymer; (3) Cool down to 55 - 65 °C, then add 8 - 13 parts by weight of chain extender, 1.5 - 3.2 parts by weight of neutralizing amine, and 60 - 85 parts by weight of acetone, and continue the reaction for 3 - 4 h; in the molecular structure of the obtained polyurethane, there are multiple groups that can react with phenolic hydroxyl groups. It includes multiple epoxy groups introduced from polyol B and polyol C on the main chain, -NCO groups at the end groups, and the remaining carboxyl groups after partially neutralizing the carboxyl groups on 2,2 - dimethylolpropionic acid (a small amount of organic amine is added). These groups can all react with the phenolic hydroxyl groups on modified Red 146, and graft Red 146 onto the polyurethane main chain.

[0005] (4) Add 10 - 18 parts by weight of modified Pigment Red 146, increase the rotation speed to 1000 rpm, raise the temperature to 90 - 95 °C and react for 2 - 3 h, then cool down to 50 - 52 °C and add 20 - 40 parts by weight of acetone to obtain the polymeric pigment.

[0006] Further, the polyol A is a macromolecular polyol with a molecular weight of 1500 - 35000; such as polyether polyol, polyester polyol, polycarbonate polyol, etc.; preferably polypropylene glycol with a molecular weight of 2000.

[0007] The polyol B is polyethylene glycol - G - glycidyl ether with a molecular weight of 500; the polyol C is a polyalkylene monobutyl polyether - ethylene oxide / propylene oxide random copolymer with a molecular weight of 1000 - 2500 g / mol, and its ethylene oxide / propylene oxide ratio is 1:1 end - group functional group.

[0008] The polyisocyanate can be one or more of aliphatic or alicyclic diisocyanates; preferably isophorone diisocyanate.

[0009] In the present invention, through a chemical modification method, the methoxy group on the molecular structure of Red 146 is modified into a phenolic hydroxyl group. And the modified Red 146 with phenolic hydroxyl groups is introduced during the synthesis of polyurethane. There are epoxy groups on the polyurethane main chain, -NCO groups at the molecular chain end groups, and the remaining carboxyl groups after neutralizing the carboxyl groups on 2,2 - dimethylolpropionic acid (a small amount of organic amine is added). These groups react with the phenolic hydroxyl groups on modified Red 146 to chemically graft Red 146 onto the polyurethane main chain. The pigment is combined with the resin in a chemical bonding manner, which can greatly improve the physical resistance such as the adhesion and water resistance of the pigment on the substrate.

[0010] Further, the catalyst is dibutyltin dilaurate; The chain extender is 2,2 - dimethylolpropionic acid; The neutralizing amine is ethanolamine.

[0011] Further, the modified Pigment Red 146 is prepared through the following steps: Mix 100 g of DMF, 100 g of pure water, and 2 g of Pigment Red 146 under stirring at a speed of 1000 rpm at 45°C. Add 0.1 g of 1-dodecanethiol, and slowly add 10 wt% NaOH aqueous solution dropwise until the pH value of the system is between 7.5 and 8.5. After reacting at 45°C for 16 h, detect the pH value of the system. After reaching 7.5 - 8.5, carry out suction filtration, washing, and drying to obtain the modified Pigment Red 146.

[0012] The second technical solution of the present invention lies in providing a preparation method of a polymer pigment emulsion. In the above polymer pigment containing 10 - 18 parts by weight of modified Pigment Red 146, add 300 - 400 parts by weight of pure water under high-speed stirring at 1500 - 2500 rpm for dispersion and emulsification for 25 - 35 min. Finally, raise the temperature to 80 - 85°C and maintain a stirring speed of 450 - 600 rpm to remove acetone to obtain a polymer pigment emulsion with a pH of 7.5 - 8.5.

[0013] Further, the method for preparing the polymer pigment into an emulsion is as follows: In the polymer pigment containing 10 - 18 parts by weight of modified Pigment Red 146, add 300 - 400 parts by weight of pure water under high-speed stirring at 1500 - 2500 rpm for dispersion and emulsification for 25 - 35 min. Finally, raise the temperature to 80 - 85°C and maintain a stirring speed of 450 - 600 rpm to remove acetone to obtain a polymer pigment emulsion with a pH of 7.5 - 8.5.

[0014] Further, the conductivity of the pure water at 25°C is not greater than 10 μS / cm.

[0015] The third technical solution of the present invention lies in providing the polymer pigment prepared by the above method.

[0016] The beneficial effects of the present invention are as follows: The polymer pigment obtained by the present invention has a particle size as small as 278 nm, and has high stability and easy dispersibility. It has good storage stability and anti-shear stability. After high-speed dispersion at a speed of 5000 rpm for 40 min on an intelligent dispersion sand mill and filtering the aqueous resin using a 200-mesh stainless steel filter screen, there is still no filter residue on the filter screen. Detailed Embodiments

[0017] The following examples are used to further illustrate the present invention, and their purpose is to illustrate the present invention rather than to limit the scope of the present invention. Unless otherwise specified below, all are in parts by weight and weight percentages.

[0018] The raw materials used in the present invention are all conventional commercially available products unless otherwise specified; the methods used in the present invention are all conventional methods in the art unless otherwise specified.

[0019] The particle size test of the polymer pigment emulsion and the aqueous color paste was carried out on a Malvern ZETASIZER 3000 HAS particle size analyzer at a test temperature of 25 °C.

[0020] The storage stability of the polymer pigment emulsion refers to the resin standing still at 60 °C for 18 days without precipitation or delamination, indicating that the storage stability of the emulsion > 12 months.

[0021] The shear stability of the polymer pigment emulsion refers to the polymer pigment emulsion being highly dispersed at a speed of 5000 rpm on an intelligent dispersion sand mill (Hangzhou Qiwei Instrument Co., Ltd.) for 40 min, and then filtering the aqueous resin through a 200-mesh stainless steel filter screen. No filter residue on the filter screen indicates good shear stability of the polymer pigment emulsion.

[0022] The glossiness test of the polymer pigment emulsion refers to scraping a film on a glass slide with a 100-μm wire bar at room temperature, drying it in a 50 °C forced-air drying oven, and then measuring it with a 60° glossiness meter.

[0023] The drying time of the polymer pigment emulsion was measured by the finger-touch method in a constant temperature and humidity chamber at 65% RH and 25 °C.

[0024] The adhesion test of the polymer pigment emulsion was carried out according to GB / T 13217.7-2009. An adhesion fastness ≥ 95% indicates excellent adhesion fastness of the polymer pigment emulsion resin.

[0025] The water resistance test of the polymer pigment emulsion refers to scraping a film on a glass slide with a 100-μm wire bar at room temperature, drying it in a 50 °C forced-air drying oven, and then immersing the glass slide in cold water for 1 h to observe the edge lifting situation.

[0026] The molecular weights described in the present invention are all number-average molecular weights, with the unit of g / mol.

[0027] The following further illustrates the embodiments of the present invention with multiple examples.

[0028] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0029] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0030] Example 1 (1) Stir and dissolve 30 g of NaNO₂ in 70 g of pure water for later use. In a 500 mL three-necked flask, add 100 g of pure water, 6 g of HCl, and 5.0 g of 3-amino-4-methoxybenzoylaniline, and stir and mix at a speed of 500 rpm for 1.5 h. Then place it in an ice-water bath and cool it to 5 °C. Add the previously prepared NaNO₂ solution. After reacting for 40 min, add an appropriate amount of urea and react until the system becomes neutral (detected using pH test paper). After the reaction is completed, perform suction filtration to obtain a yellow and clear diazo solution.

[0031] (2) In a 500 mL three-necked flask, add 80 g of pure water, 0.72 g of NaOH, and 3.2 g of N-(4-chloro-2,5-dimethoxyphenyl)-3-hydroxy-2-naphthamide, and react at 90 °C at a rotation speed of 600 rpm for 1 h. Then place it in an ice-water bath and cool it to 5 °C. Use a constant-pressure dropping funnel to slowly add the previously prepared yellow and clear diazo solution into the flask. During the process, use anhydrous sodium acetate to adjust the pH of the system to neutral (detected using pH test paper). After the dropping is completed, keep stirring for 1 h. Perform suction filtration, wash with pure water at 60 - 70 °C until the washing liquid becomes neutral (detected using pH test paper), and dry at 100 °C to obtain the red solid of Pigment Red 146.

[0032] (3) Stir and dissolve 10 g of NaOH in 90 g of pure water for later use. In a 500 mL three-necked flask, add 100 g of DMF, 100 g of pure water, and 2 g of the previously obtained red solid, and stir and mix at a rotation speed of 1000 rpm at 45 °C. Add 0.1 g of 1-dodecanethiol, and slowly add the previously prepared NaOH aqueous solution until the pH value of the system is between 7.5 and 8.5. Keep reacting at 45 °C for 16 h, then detect the pH value of the system. After it reaches 7.5 - 8.5, perform suction filtration, washing, and drying to obtain the red solid of modified Pigment Red 146.

[0033] (4) Add 100 parts by weight of polypropylene glycol with a molecular weight of 2000 (Sinopharm Chemical Reagent Co., Ltd.), 4 parts by weight of G 500 polyethylene glycol ether with a multi-molecular weight of 500 (Clariant), and 4 parts by weight of B 11 / 150 polyalkylene monobutyl polyether with a multi-molecular weight of 2500 (Clariant) into a flask. Under stirring at 250 rpm, heat up to 70 °C for vacuum dehydration for 1 h. Then add 54 parts by weight of isophorone diisocyanate (Sinopharm Chemical Reagent Co., Ltd.) and 0.058 parts by weight of dibutyltin dilaurate (Jinan Dahui Chemical Technology Co., Ltd.), and react at 85 °C for 2 h to obtain a prepolymer. Then cool down to 65 °C, and add 13 parts by weight of 2,2-dimethylolpropionic acid (Sinopharm Chemical Reagent Co., Ltd.), 1.5 parts by weight of ethanolamine (Sinopharm Chemical Reagent Co., Ltd.), and 85 parts by weight of acetone (Sinopharm Chemical Reagent Co., Ltd.). Continue to react for 3.5 h, then add 18 parts by weight of modified pigment red 146, increase the rotation speed to 1000 rpm, heat up to 90 °C and react for 2 h (pay attention to controlling the acetone reflux situation during the process). Then cool down to 50 °C and add 40 parts by weight of acetone (Sinopharm Chemical Reagent Co., Ltd.). Add the obtained polymer into 400 parts by weight of pure water dispersion milk under high-speed stirring at 1500 rpm for 30 min. Finally, heat up to 85 °C and maintain a stirring speed of 600 rpm to remove acetone to obtain a polymer pigment emulsion with a pH of 7.5 - 8.5.

[0034] Example 2: Steps 1 - 3 are the same as in Example 1.

[0035] In a four-necked flask equipped with an electric stirrer, a reflux condenser, and a mercury thermometer, 90 parts of polypropylene glycol with a molecular weight of 2000 (Sinopharm Chemical Reagent Co., Ltd.), 3 parts of G 500 polyethylene glycol ether with a multi-molecular weight of 500 (Clariant), and 2 parts of B 11 / 150 polyalkylene monobutyl polyether with a multi-molecular weight of 2500 (Clariant) were added. Under stirring at 250 rpm, the temperature was raised to 60 °C and vacuum dehydration was carried out for 1.5 h. Then, 30 parts of isophorone diisocyanate (Sinopharm Chemical Reagent Co., Ltd.) and 0.05 part of dibutyltin dilaurate (Jinan Dahui Chemical Technology Co., Ltd.) were added, and the reaction was carried out at 80 °C for 2 h to obtain a prepolymer. Then, the temperature was lowered to 55 °C, and then 10 parts of 2,2-dimethylolpropionic acid (Sinopharm Chemical Reagent Co., Ltd.), 2 parts of ethanolamine (Sinopharm Chemical Reagent Co., Ltd.), and 60 parts of acetone (Sinopharm Chemical Reagent Co., Ltd.) were added. After continuing the reaction for 3 h, 10 parts of modified pigment red 146 were added, the rotation speed was increased to 1000 rpm, and the temperature was raised to 95 °C and the reaction was carried out for 2 h (pay attention to controlling the acetone reflux during the process). Then, the temperature was lowered to 52 °C and 20 parts of acetone (Sinopharm Chemical Reagent Co., Ltd.) were added. The obtained polymer was added to 300 parts of pure water dispersion emulsion under high-speed stirring at 1500 rpm for 25 min, and finally the temperature was raised to 80 °C and the stirring speed was maintained at 600 rpm to remove acetone to obtain a polymer pigment emulsion with a pH of 7.5 - 8.5.

[0036] Example 3: Steps 1 - 3 are the same as in Example 1.

[0037] In a four-necked flask equipped with an electric stirrer, a reflux condenser, and a mercury thermometer, add 120 parts of polypropylene glycol with a molecular weight of 2000 (Sinopharm Chemical Reagent Co., Ltd.), 5 parts of G 500 polyethylene glycol ether with a multi-molecular weight of 500 (Clariant), and 3 parts of B 11 / 150 polyalkylene monobutyl polyether with a multi-molecular weight of 2500 (Clariant). Under stirring at 450 rpm, heat up to 60 °C and vacuum dehydrate for 1 h. Then add 48 parts of isophorone diisocyanate (Sinopharm Chemical Reagent Co., Ltd.) and 0.05 part of dibutyltin dilaurate (Jinan Dahui Chemical Technology Co., Ltd.). React at 82 °C for 2.5 h to obtain a prepolymer. Then cool down to 60 °C, and add 8 parts of 2,2-dimethylolpropionic acid (Sinopharm Chemical Reagent Co., Ltd.), 3.2 parts of ethanolamine (Sinopharm Chemical Reagent Co., Ltd.), and 80 parts of acetone (Sinopharm Chemical Reagent Co., Ltd.). Continue to react for 4 h, then add 15 parts of modified pigment red 146, increase the rotation speed to 1000 rpm, heat up to 90 °C and react for 3 h (pay attention to controlling the acetone reflux during the process). Then cool down to 50 °C and add 30 parts of acetone (Sinopharm Chemical Reagent Co., Ltd.). Add 400 parts of pure water dispersion milk to the obtained polymer under high-speed stirring at 2500 rpm for 35 min. Finally, heat up to 85 °C and maintain a stirring speed of 450 rpm to remove acetone to obtain a polymer pigment emulsion with a pH of 7.5 - 8.5.

[0038] Example 4 The difference from Example 1 is that polyol A is a polyether polyol with a molecular weight of 1500, and polyol C is a polyalkylene monobutyl polyether-ethylene oxide / propylene oxide random copolymer with a molecular weight of 1000 g / mol.

[0039] Example 5 The difference from Example 1 is that polyol A is a polycarbonate polyol with a molecular weight of 35000.

[0040] Comparative Example 1: The difference from the example lies in using Pigment Red 146 to replace the modified Pigment Red 146. The specific operation is as follows: In a four-necked flask equipped with an electric stirrer, a reflux condenser, and a mercury thermometer, add 100 parts of polypropylene glycol with a molecular weight of 2000 (Sinopharm Chemical Reagent Co., Ltd.), 4 parts of G 500 polyethylene glycol ether with a multi-molecular weight of 500 (Clariant), and 4 parts of B 11 / 150 polyalkylene monobutyl polyether with a multi-molecular weight of 2500 (Clariant). Under stirring at 250 rpm, heat up to 70 °C for vacuum dehydration for 1 h, then add 54 parts of isophorone diisocyanate (Sinopharm Chemical Reagent Co., Ltd.) and 0.058 parts of dibutyltin dilaurate (Jinan Dahui Chemical Technology Co., Ltd.), and react at 85 °C for 2 h to obtain a prepolymer. Then cool down to 65 °C, and then add 13 parts of 2,2-dimethylolpropionic acid (Sinopharm Chemical Reagent Co., Ltd.), 1.5 parts of ethanolamine (Sinopharm Chemical Reagent Co., Ltd.), and 85 parts of acetone (Sinopharm Chemical Reagent Co., Ltd.). Continue to react for 3.5 h, then add 18 parts of Pigment Red 146, increase the rotation speed to 1000 rpm, heat up to 90 °C and react for 2 h (pay attention to controlling the acetone reflux during the process), and then cool down to 50 °C and add 40 parts of acetone (Sinopharm Chemical Reagent Co., Ltd.). Add the obtained polymer to 400 parts of pure water dispersion under high-speed stirring at 1500 rpm for 30 min, and finally heat up to 85 °C and maintain a stirring speed of 600 rpm to remove acetone.

[0041] In Comparative Example 1, layering occurred after standing at room temperature for 1 h after the reaction, the pigment settled to the bottom of the beaker, and the supernatant was slightly light red. This indicates that the unmodified Pigment Red 146 cannot form a chemical graft copolymer with the polyurethane of the invention, resulting in a phase separation instability phenomenon.

[0042] Comparative Example 2: In a four-necked flask equipped with an electric stirrer, a reflux condenser, and a mercury thermometer, 100 parts of polypropylene glycol with a molecular weight of 2000 (Sinopharm Chemical Reagent Co., Ltd.), 4 parts of G 500 polyethylene glycol ether with a multi-molecular weight of 500 (Clariant), and 4 parts of B 11 / 150 polyalkylene monobutyl polyether with a multi-molecular weight of 2500 (Clariant) were added. Under stirring at 250 rpm, the temperature was raised to 70 °C for vacuum dehydration for 1 h. Then, 54 parts of isophorone diisocyanate (Sinopharm Chemical Reagent Co., Ltd.) and 0.058 parts of dibutyltin dilaurate (Jinan Dahui Chemical Technology Co., Ltd.) were added, and the reaction was carried out at 85 °C for 2 h to obtain a prepolymer. Then, the temperature was lowered to 65 °C, and then 13 parts of 2,2-dimethylolpropionic acid (Sinopharm Chemical Reagent Co., Ltd.), 1.5 parts of ethanolamine (Sinopharm Chemical Reagent Co., Ltd.), and 85 parts of acetone (Sinopharm Chemical Reagent Co., Ltd.) were added. After continuing the reaction for 3.5 h, the temperature was lowered to 50 °C, and 40 parts of acetone (Sinopharm Chemical Reagent Co., Ltd.) were added. The obtained polymer was added to 400 parts of pure water under high-speed stirring at 1500 rpm to disperse the emulsion for 30 min, and finally the temperature was raised to 85 °C and the stirring speed was maintained at 600 rpm to remove acetone to obtain a polyurethane emulsion with a pH of 7.5 - 8.5.

[0043] Add 20 parts of the above polyurethane emulsion to the dispersion kettle, start stirring, and keep the rotation speed at 100 rpm. Then, 30 parts of pure water, 2 parts of BYK-190 dispersant (BYK), 0.04 parts of DAPPO ® DF 3163 (Degen), and 10 parts of Pigment Red 146 were added in sequence, and after stirring and mixing evenly at a rate of 200 rpm, it was transferred to a horizontal sand mill, ground for 3 passes, and then filtered and discharged to obtain an aqueous color paste; then, the obtained aqueous color paste, 20 parts of the above polyurethane emulsion, 28 parts by weight of pure water, 0.8 parts by weight of ANTI-TERRA-250 (BYK), and 0.06 parts of DAPPO ® DF 3163 (Degen) were added to the dispersion tank, stirred at a rate of 150 rpm for 0.5 h, and then filtered and discharged to obtain a red ink of self-made PU + Pigment Red 146.

[0044] Comparative Example 3: Replace Pigment Red 146 in Comparative Example 2 with the self-made modified Pigment Red 146 of the present invention, and keep the rest of the formula and process unchanged to obtain a red ink of self-made PU + modified Pigment Red 146.

[0045] Comparative Example 4: Add 20 parts of Adwel 1645 polyurethane emulsion (Wanhua Chemical Company) into the dispersion kettle, start stirring, keep the speed at 100 rpm, then add 30 parts of purified water, 2 parts of BYK-190 dispersant (BYK), 0.04 parts of DAPPO ® DF 3163 (Deqian Company) and 10 parts of Pigment Red 146 were stirred and mixed at a rate of 200 rpm and then transferred to a horizontal sand mill. After grinding for 3 times, the material was filtered to obtain a water-based color paste. Then, the obtained water-based color paste, 20 parts of the above-mentioned polyurethane emulsion, 28 parts by weight of purified water, 0.8 parts by weight of ANTI-TERRA-250 (Bick Company), and 0.06 parts by weight of DAPPO were sequentially added. ® DF 3163 (Deqian Company) was added into the dispersion tank, stirred at 150 rpm for 0.5 h, and then filtered to obtain the commercially available PU + Pigment Red 146 red ink.

[0046] Comparative Example 5: The Pigment Red 146 in Comparative Example 4 was replaced with the modified Pigment Red 146 prepared in the present invention, and the other formulas and processes remained unchanged to obtain a red ink of commercially available PU + modified Pigment Red 146.

[0047] Table 1. Performance comparison of examples and comparative examples

[0048] As can be seen from Table 1, the particle size of the polymer pigment emulsion obtained by chemical grafting polymerization on the resin chain segment in Example 1 is significantly lower than the particle size of the color paste obtained by physical grinding in other comparative examples. This is also the reason why the glossiness of the resin film in Example 1 is significantly higher than that in the comparative examples. The present invention combines the two and disperses them in water. The dispersibility of the pigment in the system and the encapsulation and film-forming properties of the resin on the pigment will be better, so it is less likely to edge. The present invention shows excellent physical resistance in terms of shear stability, adhesion and water resistance. At the same time, the drying time of the polymer pigment resin is relatively short.

[0049] The above embodiments describe in detail the structure, features and effects of the present invention. The above are only preferred embodiments of the present invention. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which do not exceed the scope covered by the specification, should be within the protection scope of the present invention.

Claims

1. A method for preparing a polymer pigment, characterized in that: The following steps are involved: (1) 90-120 parts by weight of polyol A, 3-5 parts by weight of polyol B and 2-4 parts by weight of polyol C are heated to 60-70°C and vacuum dehydrated for 1-1.5 hours under stirring at 250-450 rpm; (2) adding 30-54 parts by weight of polyisocyanate and 0.05-0.058 parts by weight of catalyst, stirring at 250-450 rpm, reacting at 80-85° C. for 2-2.5 hours to obtain a primary polymer; (3) The primary polymer is cooled to 55-65°C, and then 8-13 parts by weight of a chain extender, 1.5-3.2 parts by weight of a neutralizing amine and 60-85 parts by weight of acetone are added, and the reaction is continued for 3-4 hours under stirring at 250-450 rpm; (4) Add 10-18 parts by weight of modified Pigment Red 146, rotate at 1000 rpm, heat to 90-95°C and react for 2-3 hours, then cool to 50-52°C and add 20-40 parts by weight of acetone to obtain a polymer pigment.

2. The preparation method according to claim 1, characterized in that: The modified Pigment Red 146 is prepared by the following steps: 100 g of DMF, 100 g of pure water and 2 g of Pigment Red 146 are stirred at 45° C. at a speed of 1000 rpm, 0.1 g of 1-dodecyl mercaptan is added, and a 10 wt % NaOH aqueous solution is added dropwise until the pH value of the system is between 7.5 and 8.5; after maintaining the reaction at 45° C. for 16 hours, when the pH value reaches 7.5-8.5, the modified Pigment Red 146 is obtained by suction filtration, washing and drying.

3. A method for preparing a polymer pigment emulsion, characterized in that: In the polymer pigment of claim 1 containing 10-18 parts by weight of modified Pigment Red 146, 300-400 parts by weight of pure water is added with high-speed stirring at 1500-2500 rpm and dispersed and emulsified for 25-35 minutes, and finally the temperature is raised to 80-85°C and the stirring speed is maintained at 450-600 rpm to remove acetone to obtain a polymer pigment emulsion with a pH of 7.5-8.

5.

4. The preparation method according to claim 3, characterized in that: The conductivity of the pure water at 25° C. is not greater than 10 us / cm.

5. The preparation method according to claim 1, characterized in that: The polyol A is a macromolecular polyol with a molecular weight of 1500-35000; The polyol B is polyethylene glycol-G-glycidyl ether with a molecular weight of 500; the polyol C is a polyalkylene monobutyl polyether-ethylene oxide / propylene oxide random copolymer with a molecular weight of 1000-2500, and its ethylene oxide / propylene oxide ratio is 1:1 terminal functional group.

6. The preparation method according to claim 1, characterized in that: The catalyst is dibutyltin dilaurate; The chain extender is 2,2-dimethylol propionic acid; The neutralizing amine is ethanolamine.

7. A polymer pigment prepared by the preparation method according to claim 1.

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