阅读说明：本技术 具有耐光高分散稳定性的杂化有机颜料粉体的制备方法 (Preparation method of hybrid organic pigment powder with light resistance and high dispersion stability ) 是由 戚栋明 胡静 陈智杰 冯梦龙 黄卓 于 2019-10-30 设计创作，主要内容包括：本发明公开了一种具有耐光、高分散稳定性的杂化有机颜料粉体的制备方法,包括：有机颜料液A经过预处理后获得含有盐分的有机颜料分散液B；聚合单体与含有乳化剂、引发剂的水相混合均匀后,经过搅拌得到单体初级乳液C；将颜料水分散液B与仅含表面活性剂的水相混合搅拌后,再经过高速剪切形成均匀稳定混合液D,之后将该混合液D升温后,开始滴加单体初级乳液C,滴加后,再反应一段时间,获得杂化颜料水分散液E,经后处理得到杂化有机颜料粉体。该方法简单且可行性高,制备的杂化颜料中颜料含量高,聚合物含量低,具有良好的显色性能和稳定性,可以实现聚合物层对颜料的保护,使其具有良好的光稳定性、沉降稳定性及分散稳定性。(The invention discloses a preparation method of hybrid organic pigment powder with light resistance and high dispersion stability, which comprises the following steps: pretreating the organic pigment liquid A to obtain organic pigment dispersion liquid B containing salt; uniformly mixing a polymerized monomer with a water phase containing an emulsifier and an initiator, and stirring to obtain a monomer primary emulsion C; and mixing and stirring the pigment water dispersion B and a water phase only containing a surfactant, then carrying out high-speed shearing to form a uniform and stable mixed solution D, heating the mixed solution D, starting to dropwise add the monomer primary emulsion C, reacting for a period of time after dropwise adding to obtain a hybrid pigment water dispersion E, and carrying out aftertreatment to obtain the hybrid organic pigment powder. The method is simple and high in feasibility, the prepared hybrid pigment is high in pigment content and low in polymer content, has good color rendering property and stability, and can protect the pigment by a polymer layer, so that the pigment has good light stability, sedimentation stability and dispersion stability.)

1. A preparation method of hybrid organic pigment powder with light resistance and high dispersion stability is characterized by comprising the following steps:

1) the organic pigment water dispersion A is used as a raw material for preparing the hybrid organic pigment;

2) pretreating the organic pigment liquid A to obtain organic pigment dispersion liquid B containing salt;

3) uniformly mixing a polymerized monomer with a water phase containing an emulsifier and an initiator, and stirring to obtain a monomer primary emulsion C;

4) mixing and stirring the pigment water dispersion B and a water phase only containing a surfactant, then carrying out high-speed shearing to form a uniform and stable mixed solution D, heating the mixed solution D, starting to dropwise add a monomer primary emulsion C, and reacting for a period of time after dropwise adding to obtain a hybrid pigment water dispersion E;

5) and (3) carrying out centrifugal washing and drying treatment on the hybrid pigment water dispersion liquid E, and finally grinding to obtain the hybrid organic pigment powder with light resistance and high dispersion stability.

2. The method for preparing a hybrid organic pigment powder with light resistance and high dispersion stability according to claim 1, wherein in the step 1), the organic pigment aqueous dispersion A comprises the following components in parts by mass;

82% -90% of water;

5 to 10 percent of organic pigment;

3 to 8 percent of inorganic salt.

3. The method for preparing a light-resistant high-dispersion-stability hybrid organic pigment powder according to claim 2, wherein in the step 1), the inorganic salt is a mixture of three salts, namely sodium chloride, sodium nitrate and sodium carbonate, and the mass ratio of the three salts is 1: 0.8-1.2: 0.6 to 1.

4. The method for preparing a hybrid organic pigment powder with light fastness and high dispersion stability according to claim 1, wherein in the step 2), the organic pigment liquid A is pretreated to obtain an organic pigment dispersion liquid B containing salt, and the method specifically comprises the following steps:

centrifuging the organic pigment liquid A at the speed of 1000-2000 rpm, removing supernatant, adding clear water for redispersion, repeating for several times until the conductivity of the organic pigment water dispersion liquid is 200-300 mu S/m, and then adding water for diluting until the solid content is 20-40% and the conductivity is 80-140 mu S/m to obtain the organic pigment dispersion liquid B containing salt.

5. The method as claimed in claim 1, wherein the step 3) is carried out by mixing four monomers of methyl methacrylate, glycidyl acrylate, butyl acrylate and methacrylamidopropyl dimethylamine.

6. The method for preparing a hybrid organic pigment powder with light fastness and high dispersion stability according to claim 5, wherein in the step 3), the mass ratio of the methyl methacrylate, the glycidyl acrylate, the butyl acrylate and the methacrylamide is 1: 0.3-0.5: 0.5-0.8: 0.1 to 0.3.

7. The method for preparing the hybrid organic pigment powder with light resistance and high dispersion stability according to claim 5, wherein in the step 3), the emulsifier is sodium dodecyl sulfate, and the dosage of the sodium dodecyl sulfate is 0.1-3% of the mass of the polymerized monomer;

the initiator is one of potassium persulfate or ammonium persulfate, and the dosage of the initiator is 0.5-4% of the mass of the polymerized monomer.

8. The preparation method of the hybrid organic pigment powder with light resistance and high dispersion stability according to claim 1, wherein in the step 4), the temperature of the mixed solution D is raised to 70-75 ℃, the monomer primary emulsion C is dripped, and the mixed solution E is reacted for 5-7 hours after being dripped for 30-60 min to obtain the hybrid pigment aqueous dispersion E.

9. The method for preparing the hybrid organic pigment powder with light fastness and high dispersion stability according to claim 1, wherein in the step 4), the surfactant is an ionic surfactant and a nonionic surfactant, and the ionic surfactant is one of sodium dodecyl sulfate and sodium dodecyl benzene sulfonate; the non-ionic surfactant is one of tween-40 and alkylphenol polyoxyethylene.

10. The method for preparing a light-fast and high dispersion stability hybrid organic pigment powder according to claim 9, wherein in the step 4), the mass ratio of the ionic surfactant to the nonionic surfactant in the surfactant is 1: 0.8 to 1.2;

the dosage of the surfactant is 0.4-1.8% of the mass of the pigment water dispersion B.

Technical Field

The invention relates to the field of preparation of hybrid organic pigment powder, in particular to a preparation method of hybrid organic pigment powder with light resistance and high dispersion stability.

Background

The organic pigment has bright color and complete color spectrum, and is widely applied to the fields of ink printing, paint, plastics and the like. Although the amount of the organic pigment used tends to increase year by year, the organic pigment has some disadvantages, such as poor light stability and thermal stability, easy damage to the molecular structure and loss of the original vivid color under long-term illumination or at higher temperature. In addition, most pigments are difficult to achieve both hydrophilicity and lipophilicity, and these are still problems to be solved.

At present, many studies on the surface modification of pigments are being made at home and abroad. The pigment is distinguished by the type of coating substance on the surface of the pigment, and there are inorganic materials such as silica, titanium dioxide, and alumina. Yuan et al used a sol-gel method to adsorb silica on a pigment, and formed a silica shell on the surface of the pigment by layer-by-layer stacking [ Chemistry of Materials2005,17,3587-3594 ]. Wu et al used direct precipitation of hydrated alumina in aqueous solutions to form uniform hydrated alumina films on the surface of organic Pigments [ Dyes and Pigments 2011,92,548-553 ]. Cao et al formed a novel organic-inorganic hybrid pigment [ Dyes and Pigments 2015,119,75-83 ] by introducing titanium dioxide particles during the preparation of organic pigment yellow by a hybrid coupling process. Other hydrous magnesium aluminum silicate clay minerals are also applied to the modification of organic pigments, such as sepiolite, and can adsorb the organic pigments to the surface thereof due to the unique lamellar structure, so as to obtain a new material with good color development performance [ Industrial & Engineering Chemical Research 2014,53,31-37 ].

The organic pigment coated by the organic polymer is widely applied to printing ink and coating, and the agglomeration of organic pigment particles is prevented mainly by improving the dispersibility, so that the application value of the organic pigment is improved. For example, researchers have introduced some polymerizable dispersants into emulsion polymerization systems, such as phthalocyanine blue powder, mixed with a solution of a pigment agent that forms a polymer coating after polymerization dispersion, and after ball milling for 2-3 hours, to form a pigment dispersion, and added monomers for copolymerization [ Progress in organic coating 2012,73,149-154 ]. In order to improve the dispersibility of the organic pigment, it has been studied to prepare resin-encapsulated particles by fine emulsion polymerization of the organic pigment in the presence of a dispersant using a ball mill. The specific operation is as follows: the pigment yellow 12 powder and the solution of the dispersant are mixed and dispersed for 10 hours under the action of a ball mill to obtain a pigment dispersion. The dispersion was then mixed with pre-emulsified monomers and initiator was added to initiate polymerization to form polymer encapsulated pigments [ Progress in organic Coating 2018,117,69-75 ].

Although many reports of organic pigment modification methods exist, most of the reports still remain in a small test stage, and the most critical reason is that the content of the organic pigment in a large amount of modified organic pigments is between 5 and 20 percent, and the content of the organic pigment in modified organic pigment powder with practical application value acknowledged in the pigment production industry is more than 60 percent.

Disclosure of Invention

The invention provides a preparation method of a hybrid organic pigment powder (namely a polymer/organic pigment-hybrid pigment with high pigment content) with light resistance and high dispersion stability, the method is simple and high in feasibility, and the prepared hybrid pigment has high pigment content, low polymer content and good color rendering property and stability. In terms of the application performance of the hybrid pigment, if inorganic substances such as silicon dioxide and the like are used for forming a protective layer, the application performance of the hybrid pigment as a coating is not high although the thermal stability and the weather resistance are improved to a certain extent, and the inorganic substances have the defects of rough hand feeling and easy shedding due to strong rigidity, so that a large amount of adhesive is required to be added in the using process. The hybrid pigment with the polymer coated on the surface of the organic pigment has good dispersibility, and when the hybrid pigment is used as a coating, the polymer can effectively prevent the coalescence among the pigments to form a uniformly spread coating.

The invention improves the proportion of the pigment in the preparation process, so that a thin polymer layer is adsorbed on the surface of the organic pigment, the polymer layer is thin and has good light transmission, the original color of the organic pigment is not affected basically, the organic pigment has excellent color and luster, and the finally obtained hybrid pigment powder can be directly used in the application field of the existing commercial pigment.

The raw materials used by the invention are organic pigment water dispersion containing a large amount of nano primary crystals and inorganic salts, and the organic pigment water dispersion is used for synthesizing the hybrid pigment after the conductivity of the water dispersion is adjusted, so that the labor cost and energy of an enterprise in baking a filter cake are saved, and the development of industrial downstream products is promoted. The preparation of the organic pigment filter cake is very complicated, such as mechanical dehydration, semi-permeable membrane filtration, electrodeposition, and cryogenic freezing. The filter cake is easy to dust during the drying process, and crystal form rearrangement can occur after drying, so that a large amount of aggregation is caused, and the coloring performance of the pigment is influenced. The traditional modification method has obvious defects, the surface of the modified organic pigment is attached with a thick packaging layer, and compared with the unmodified pigment, the hue, the lightness and the saturation of the color of the modified organic pigment are greatly different.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method for preparing a light-fast high dispersion stability hybrid organic pigment powder (i.e. a high pigment content polymer/organic pigment-hybrid pigment) comprises the following steps:

1) the organic pigment water dispersion A is used as a raw material for preparing the hybrid organic pigment;

2) pretreating the organic pigment liquid A to obtain organic pigment dispersion liquid B containing salt;

3) uniformly mixing a polymerized monomer with a water phase containing an emulsifier and an initiator, and stirring at a high speed to obtain a monomer primary emulsion C;

4) mixing and stirring the pigment water dispersion B and a water phase only containing a surfactant, then carrying out high-speed shearing to form a uniform and stable mixed solution D, heating the mixed solution D, starting to dropwise add a monomer primary emulsion C, and reacting for a period of time after dropwise adding to obtain a hybrid pigment water dispersion E;

5) and (3) carrying out centrifugal washing and drying treatment on the hybrid pigment water dispersion liquid E, and finally grinding to obtain the hybrid organic pigment powder with light resistance and high dispersion stability.

In the step 1), the organic pigment water dispersion A consists of the following components in parts by mass;

82% -90% of water;

5 to 10 percent of organic pigment;

3 to 8 percent of inorganic salt;

more preferably, the organic pigment water dispersion A comprises the following components in parts by mass;

82% -90% of water;

5 to 10 percent of organic pigment;

5 to 6 percent of inorganic salt;

the organic pigment is a pigment primary nanocrystal, and the organic pigment water dispersion liquid A is a product obtained by coupling organic pigment color-assisting part molecules and chromophoric part molecules in water and precipitating crystals. The organic pigment dispersion liquid A is an organic pigment dispersion liquid containing a large amount of pigment primary nano crystals and inorganic salt, and the preparation method is mainly based on that the pigment color-assisting part molecules are coupled and connected with the chromophoric part molecules and then crystals are separated out in water. At present, no relevant research reports exist on the raw materials for preparing the hybrid pigment.

The organic pigment is azo type pigment, heterocyclic type pigment or condensed ring ketone type pigment.

Wherein: azo type pigments include pigment red 170, pigment yellow 83, pigment brown 41; heterocyclic type pigments include pigment yellow 139, pigment red 19, pigment violet 19; the fused ring ketone pigment comprises permanent red F5RK and pigment yellow 191.

The inorganic salt is a mixture of three salts of sodium chloride, sodium nitrate and sodium carbonate, and the mass ratio of the three salts is 1: 0.8-1.2: 0.6-1, most preferably, the inorganic salt is a mixture of three salts of sodium chloride, sodium nitrate and sodium carbonate, and the mass ratio of the three salts is 1: 1: 0.8.

in the step 2), the organic pigment liquid A is pretreated to obtain organic pigment dispersion liquid B containing salt, and the method specifically comprises the following steps:

centrifuging the organic pigment liquid A at the speed of 1000-2000 rpm, removing supernatant, adding clear water for redispersion, repeating for several times until the conductivity of the organic pigment water dispersion liquid is 200-300 mu S/m, and then adding water for diluting until the solid content is 20-40% and the conductivity is 80-140 mu S/m to obtain the organic pigment dispersion liquid B containing salt.

According to the invention, after the organic pigment liquid is pretreated, a part of salt is removed, a part of salt is reserved, and under the influence of the reserved salt, the polymer monomer can be polymerized on the surface of the organic pigment under the influence of hydrogen bonds, ion acting force and the like, so that the novel polymer-coated hybrid pigment is formed. The morphological structure of the hybrid pigment is different from a core-shell structure or a pomegranate structure, and the polymer is adsorbed on the surface of the organic pigment in the form of a polymeric chain segment.

Repeating for several times until the conductivity of the organic pigment water dispersion liquid is 200-300 mu S/m. And then, adding water into the pretreatment solution to dilute the pretreatment solution to obtain an organic pigment water dispersion B with solid content of 20-40% and conductivity of 80-140 muS/m and containing a certain salt. Because the organic pigment in B has very good wettability, the time for wetting the solid powder with the solvent can be saved compared with an organic pigment filter cake.

In step 3), the polymerized monomer is a mixture of four monomers, namely Methyl Methacrylate (MMA), glycidyl acrylate (GMA), Butyl Acrylate (BA) and methacrylamide propyl Dimethylamine (DMAPMA), wherein the formula of the methacrylamide propyl Dimethylamine (DMAPMA) is as follows:

the mass ratio of Methyl Methacrylate (MMA), glycidyl acrylate (GMA), Butyl Acrylate (BA) and methacrylamide propyl Dimethylamine (DMAPMA) is 1: 0.3-0.5: 0.5-0.8: 0.1 to 0.3.

The stirring time is 30-60 min, and the uniform dispersion of a mixed system is ensured. The emulsifier is Sodium Dodecyl Sulfate (SDS), the dosage of the emulsifier is 0.1-3% of the mass of the polymerized monomer, the emulsifier is further optimized to be 0.5-2% of the mass of the polymerized monomer (further preferably 0.5-1%), the emulsifier used for pre-emulsification is too little to achieve the pre-emulsification effect, too much emulsifier is easy to form free blank colloidal particles by self-nucleation to influence the modification, and the compounding efficiency of the emulsifier and the free blank colloidal particles is low.

The initiator is one of potassium persulfate (KPS) or Ammonium Persulfate (APS), and the dosage of the initiator is 0.5-4% of the mass of the polymerized monomer.

In the step 4), after the temperature of the mixed solution D is raised to 70-75 ℃, dropwise adding the monomer primary emulsion C, dropwise adding for 30-60 min, and reacting for 5-7 h, wherein the dropwise adding time is 30-60 min, the reaction time is 5-7 h, and the temperature is 70-75 ℃.

The surfactant is an ionic surfactant and a nonionic surfactant, and the ionic surfactant is one of Sodium Dodecyl Sulfate (SDS) and Sodium Dodecyl Benzene Sulfonate (SDBS); the non-ionic surfactant is one of Tween-40 (T-40) and alkylphenol polyoxyethylene ether (OP-10). In the surfactant, the mass ratio of the ionic surfactant to the nonionic surfactant is 1: 0.8 to 1.2 (most preferably 1: 1).

The dosage of the surfactant (i.e. the total dosage of the ionic surfactant and the nonionic surfactant) is 0.4-1.8% of the mass of the pigment water dispersion B.

Dissolving the nonionic surfactant and the ionic surfactant in deionized water, and stirring to form a uniform continuous phase. Mixing B with the mixture according to the step 4). The nonionic emulsifier can prevent the contact among pigment particles to a certain extent due to longer molecular chains, while the ionic emulsifier mainly forms micelles, so that the organic pigment dispersion has good dispersibility due to electrostatic repulsion of hydrophilic ends, and a good basis is provided for subsequent polymerization. Because the system of the invention needs to always contain a certain amount of salt (about 1-3% of the total mass), the ionic emulsifier alone is difficult to stabilize the dispersion system, and the ionic emulsifier and the nonionic emulsifier need to be combined for stable dispersion.

Wherein the ionic surfactant used in the present invention is one or both of Sodium Dodecyl Sulfate (SDS) and Sodium Dodecyl Benzene Sulfonate (SDBS); the nonionic surfactant is one or two of alkylphenol polyoxyethylene ether (OP-10), stearyl alcohol polyoxyethylene (O-50) and alkylphenol polyoxyethylene ether (OP-10). The dosage of the nonionic surfactant and the dosage of the ionic surfactant both account for 2 to 5 percent of the mass of the organic pigment. When the surfactant is in an unsaturated state, the composition between the polymer and the pigment is facilitated; when the amount of the surfactant is excessively large, the number of micelles generated increases, and the blank latex formed also increases, so that the efficiency of compounding the polymer with the organic pigment decreases.

In the step 4), the formed dispersion C is transferred into a reaction device, the primary emulsion D formed in the step 4) is added into the reaction device in a dropwise adding mode, and the dropping speed is controlled to enable D to be uniformly dropped. The liquid drops dripped within unit time are simulated to be spherical, and in the case of crude emulsion with the same volume, the longer the dripping time is, the smaller the liquid drop volume is, the larger the specific surface area is, the higher the probability of contact with the organic pigment is, and the contact area of the monomer liquid drops and the organic pigment is a direct reason for the composite efficiency. The crude emulsion is generally dripped within 30-60 min, when the dripping time is less than 30min, a large amount of monomers quickly form polymers under the action of an initiator, the contact area with organic pigments is relatively small, and blank latex is increased; when the dripping time exceeds 60min, the crude emulsion which is originally uniformly mixed gradually separates phases due to the instability of the system, so that water and oil stratification is formed, and the polymerization efficiency is influenced. The mixed system continues to react for 5-7 hours at the reaction temperature of 70-75 ℃.

The preparation method provided by the invention is mainly combined with the production process of a pigment production company, and the preparation of the hybrid pigment is carried out by utilizing special raw materials and methods.

Compared with the prior art, the invention has the following advantages:

1. the polymerization process of this patent differs from conventional miniemulsion or emulsion polymerization in that the pigment used is salt-containing, and in general, the presence of excess salt results in emulsion breaking destabilization. The polymerization condition in the invention is to allow a little salt, which is helpful for the adsorption of the polymerized monomer, thereby achieving better coating effect.

2. The invention has the advantages of low content of the surfactant, less blank latex formed in the polymerization process, less consumption of the monomer in the synthesis process, and accurate control of the dropping rate, so that the compounding efficiency of the polymer and the organic pigment is high.

3. The content of the organic pigment in the hybrid pigment powder exceeds 90 percent, the polymer content is less than 10 percent, the hybrid pigment prepared by the invention can realize the protection of a polymer layer on the pigment, so that the hybrid pigment has good light stability, sedimentation stability and dispersion stability, the change of the color light and other application properties of the pigment is less, and the hybrid pigment powder can directly replace the existing organic pigment powder in the fields of ink printing, paint and the like.

Drawings

FIG. 1 is a transmission electron micrograph of an unmodified pigment of comparative example 1 and a hybrid pigment formed according to example 11, wherein a in FIG. 1 is a transmission electron micrograph of an unmodified pigment of comparative example 1, and b in FIG. 1 is a transmission electron micrograph of a hybrid pigment formed according to example 11.

FIG. 2 is a photograph of the unmodified pigment from comparative example 1 and the hybrid pigment from example 11 as a function of time under xenon lamp illumination, wherein a in FIG. 2 is a photograph of the unmodified pigment from comparative example 1 as a function of time under xenon lamp illumination, and b in FIG. 2 is a photograph of the hybrid pigment from example 11 as a function of time under xenon lamp illumination;

FIG. 3 is a photograph of an unmodified pigment from comparative example 1 (left) and a hybrid pigment from example 11 (right) after centrifugation;

FIG. 4 is a graph of the absorption of an organic pigment at the maximum absorption wavelength of ultrasound as a function of time, the gridline (unmodified pigment from comparative example 1), and the dotted line (hybrid pigment from example 11).

Detailed Description

The invention is further described below with reference to specific examples, but the scope of the invention is not limited thereto, and in the examples, the percentages are by weight unless otherwise specified:

according to the feeding proportion and conditions shown in tables 1 and 2, the hybrid pigment powder is prepared by the following steps:

1. the organic pigment water dispersion liquid A shown in the table 1 is used as a raw material, the components of the organic pigment water dispersion liquid A are shown in the table 1, and the inorganic salt is a mixture of three salts of sodium chloride, sodium nitrate and sodium carbonate, wherein the mass ratio of the three salts is 1: 1: 0.8.

2. centrifuging the organic pigment liquid A at the speed of 1500rpm, removing supernatant, adding clear water for redispersion, repeating for several times until the conductivity of the organic pigment water dispersion liquid is 200-300 mu S/m, and then diluting with water until the solid content is 20-40% and the conductivity is 80-140 mu S/m to obtain a salt-containing organic pigment dispersion liquid B;

3. according to the formula shown in the table 2, uniformly mixing a polymerization monomer with a water phase containing an emulsifier and an initiator, and stirring for 45min to obtain a monomer primary emulsion C;

4. mixing and stirring an organic pigment dispersion liquid B1000g with a solid content of 20-40% with a water phase only containing a surfactant according to a formula shown in Table 2, performing high-speed shearing by using a high-speed shearing dispersion emulsifying machine to form a uniform and stable mixed liquid D, heating the uniform and stable mixed liquid D to a reaction temperature of 70-75 ℃, and then starting to dropwise add a monomer primary emulsion C, wherein the dropwise adding time is 45min, and the reaction time is 6.5h, so as to obtain a hybrid pigment water dispersion liquid E, wherein the mass ratio of an ionic surfactant to a non-ionic surfactant in the surfactant is 1: 1.

5. and (3) centrifugally washing the hybrid pigment water dispersion liquid E for 5 times, drying, and finally grinding to obtain the hybrid organic pigment powder with light resistance and high dispersion stability.

TABLE 1 characterization of the constituents of the aqueous dispersion A of organic pigments

Table 2: preparation formula of hybrid pigment

Comparative example:

the comparative example was prepared as follows:

1. selecting the organic pigment dispersion liquid A same as the organic pigment dispersion liquid A in each embodiment, carrying out certain pretreatment to obtain an organic pigment dispersion liquid B containing a certain salt, mixing and stirring the organic pigment dispersion liquid B1000g with the solid content of 20-40% and an aqueous phase only containing an emulsifier, and carrying out high-speed shearing to form a uniform and stable mixed liquid C.

2. And mixing an initiator, a small amount of an emulsifier and water to obtain a monomer-free mixed solution F.

3. And heating the mixed solution C to a specific reaction temperature, and then starting dropwise adding F for 30-60 min, wherein the reaction time is 6-7 h and the temperature is 70-75 ℃, so as to obtain the unmodified pigment water dispersion.

4. And (3) centrifugally washing the unmodified pigment water dispersion for 5 times, drying, and finally grinding to obtain the comparative unmodified pigment powder.

The hybrid pigment powders obtained in examples 1 to 16 and the unmodified pigment obtained in comparative example 1 were subjected to a test.

The measurement method of each data is as follows:

1. the particle size was measured using a nanoscale laser particle sizer (Nano-90 type Nano laser particle sizer (malvern instruments ltd, uk), and the average particle size of the obtained hybrid pigment was denoted as P.

2. The absorbance A at the maximum absorption wavelength of the hybrid pigment was measured using an ultraviolet-visible spectrophotometer (UV-2600 type ultraviolet-visible spectrophotometer, manufactured by Nippon Kanjin).

3. The components of the hybrid pigment were analyzed using a thermogravimetric analyzer (PYRIS type 1 thermogravimetric analyzer, PE company, USA), the percentage of the surface polymer and the organic pigment to the total mass of the hybrid pigment was measured according to the different thermal decomposition temperatures of the two components, and the ratio of the organic pigment to the total mass of the hybrid pigment was denoted as T.

The method for testing the light resistance, the dispersion stability and the amphipathy of the hybrid pigment powder comprises the following steps:

in order to verify the light resistance, dispersion stability and amphiphilicity of the prepared hybrid pigment, the particle size of the obtained hybrid pigment powder was first tested and the result is noted as P₀. Then, the hybrid pigment is respectively subjected to ultrasonic treatment (in an ultrasonic cell crusher, the power is 150W, ultrasonic treatment is carried out for 1h) and illumination treatment (in a photochemical reaction instrument, an 800W xenon lamp is used, and illumination is carried out for 24h), and then particle size measurement and visible light absorbance test are carried out. The average particle diameter of the ultrasonically treated hybrid pigment is denoted as P₁And the rate of change of absorbance is denoted as S₁The average particle diameter of the hybrid pigment after light irradiation treatment is denoted as P₂And the rate of change of absorbance is denoted as S₂。

Wherein the rate of change of the absorption value S ═ A₁(A₂)-A₀]/A₀；

A₀Represents the absorbance of the hybrid pigment at the maximum absorption wavelength;

A₁and A₂Representing the absorbance of the hybrid pigment at the maximum wavelength after sonication or illumination.

Invention by comparison of P₀，P₁，P₂Value of (A) and S₁And S₂The dispersion stability of the hybrid pigment was judged. I.e. P₁And P₂And P₀The closer the two are, the less the dispersion state of the hybrid pigment is affected by the ultrasonic and strong light ultrasonic irradiation, and the pigment particles are not obviously agglomerated and dissociated, so the hybrid pigmentThe better the dispersion stability of the pigment. In the same way, S₁，S₂The smaller the value of (A) is, the closer to 0 is, the smaller the influence of ultrasonic and intense light super-irradiation on the molecular structure of the hybrid pigment is, and the more stable the color light of the pigment particles is.

The test results are shown in table 3:

TABLE 3

As is clear from Table 3, the hybrid pigments obtained in examples 1 to 16 of the present invention are superior to the unmodified organic pigment in dispersion stability, amphiphilicity, and light resistance, compared to the unmodified organic pigment obtained in comparative example 1.

As shown in FIG. 1, in the case of the unmodified pigment of comparative example 1 in FIG. a and the hybrid pigment of example 11 in FIG. b, the particle size of the original pigment is about 200nm and the original pigment is observed to be in a granular or flake distribution by observing the morphology change of the organic pigment before and after modification by a transmission electron microscope. The particle size of the hybrid pigment prepared by the miniemulsion method is about 400nm, the surface of the pigment red 170 has obvious polymer adsorption, and a shell layer formed by the polymer is thin and completely covered.

As shown in FIG. 2, the upper and lower images are photographs of the unmodified pigment obtained in comparative example 1 and the hybrid pigment obtained in example 11, respectively, with time under xenon lamp irradiation, and the organic pigment used in the present invention has a high solid content and a relatively low monomer ratio, so that the organic material adsorbed on the surface of the organic pigment is reduced, but the stability is not affected. The following is a test of its light stability at 24h, illuminated with xenon lamp (800W) for 24h, and observed with sampling every 6 h. As can be seen from the two groups of photos, as the illumination time is prolonged, the organic pigment has large surface energy, strong hydrophobicity and easy agglomeration, and is gradually decomposed into single particles under illumination, the dispersibility is improved, and the color gradually becomes dark. The hybrid pigment not only improves the dispersion stability of the original pigment, but also improves the light stability of the original pigment because the polymer layer has a certain shielding effect on a light source.

As shown in FIG. 3, the unmodified pigment (left) obtained in comparative example 1 and the hybrid pigment (right) obtained in example 11 were photographed after centrifugation, and the products of comparative example 1 and example 8 were subjected to low-speed centrifugation (2000r/min, 30min) from the original pigment and the hybrid pigment after centrifugation, it was found that the original pigment settled at the bottom of the test tube, and the hybrid pigment was uniformly dispersed due to better settling stability.

As shown in FIG. 4, the absorption values of the organic pigments at the maximum absorption wavelength of the ultrasonic action are plotted against time, the squares (unmodified pigment obtained in comparative example 1), and the circles (hybrid pigment obtained in example 11). As can be seen from fig. 4, the absorption value of the unmodified pigment gradually becomes larger, indicating that the aggregation of the particles gradually looses, while the hybrid pigment has no significant change under the ultrasonic condition, indicating that the hybrid pigment has good stability.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention, and it is therefore to be understood that the invention is not limited by the scope of the appended claims.