CN111286233A - A kind of gel preparation method of fluorescent pigment - Google Patents

Abstract

The invention relates to the technical field of preparation of fluorescent pigments, and discloses a method for preparing a gel of fluorescent pigments, comprising the following steps: (1) mixing and grinding inorganic silicates and fluorescent dyes to obtain mixed powder; (2) mixing sodium alginate Add water, stir until completely dissolved, then add the mixed powder, stir evenly to obtain a mixed slurry; (3) add anhydrous calcium chloride to the mixed slurry, stir evenly to obtain a gel intermediate; (4) Sodium carbonate is added to the gel intermediate, stirred uniformly and then precipitated, the obtained product is washed until there is no floating color, and then dried to obtain the fluorescent pigment. The invention adsorbs fluorescent dye molecules through sodium alginate gel, and converts the gel layer into an inorganic salt protection layer, so that the fluorescent pigment is not easy to bleed, has good acid and alkali resistance, and is more stable.

Description

A kind of gel preparation method of fluorescent pigment

technical field

The invention relates to the technical field of preparation of fluorescent pigments, in particular to a method for preparing gels of fluorescent pigments.

Background technique

After the fluorescent pigment absorbs visible light and ultraviolet light, it can convert the original ultraviolet light that the human eye cannot perceive into visible light of a certain color, which is superimposed with the conventional reflected light, and its total reflected light intensity is higher than that of ordinary pigments, forming a very bright color. . These fluorescent pigments themselves often have inherent deficiencies in properties such as light resistance and solvent resistance, so they are generally fused into the framework of polymer materials by chemical or physical methods, and then further processed into pigments.

At present, domestic environmentally friendly fluorescent liquid pigments are generally produced by emulsion polymerization. For example, "a preparation method of water-based sunlight fluorescent pigment paste" disclosed in Chinese patent documents, its bulletin number CN103555069A, including the preparation of dispersion system, pre-emulsion Preparation, reaction and addition of redox to initiate system reaction to obtain water-based sunlight fluorescent pigment paste.

However, the fluorescent pigment prepared by emulsion polymerization has strong hydrophilicity on the polymer surface during printing and dyeing and coating application. The internal resin and dye are attracted to each other by limited van der Waals force, and the dye in the polymer is easily dissolved in water or other In the medium, which affects the performance of the product, such as soaping, temperature resistance, color bleeding, etc., it will also generate a large amount of waste water, causing water pollution.

SUMMARY OF THE INVENTION

The invention is to overcome the fact that the fluorescent pigment prepared by the emulsion polymerization method in the prior art has strong hydrophilicity on the surface of the polymer in the process of printing, dyeing and coating application, and the dye in the polymer is easily dissolved in water or other media, thereby The performance of the product is affected, and problems such as color bleeding are likely to occur. A method for preparing a fluorescent pigment gel is provided. The fluorescent dye molecules are adsorbed by sodium alginate gel with strong adsorption force on the dye molecules, and the gel layer is converted into The inorganic salt protective layer further coats and fixes the dye molecules, improves the acid and alkali resistance of the protective layer, and the obtained fluorescent pigment is not easy to bleed, has strong acid and alkali resistance, and has good performance.

In order to achieve the above object, the present invention adopts the following technical solutions:

A kind of gel preparation method of fluorescent pigment is characterized in that, comprises the steps:

(1) Mixing and grinding inorganic silicate and fluorescent dye to obtain mixed powder;

(2) adding sodium alginate to the water, stirring until completely dissolved, adding the mixed powder, and stirring to obtain a mixed slurry;

(3) adding anhydrous calcium chloride to the mixed slurry, stirring to obtain a gel intermediate;

(4) adding sodium carbonate to the gel intermediate, stirring evenly and then precipitating, washing the obtained product until there is no floating color, and drying to obtain the fluorescent pigment.

Preferably, the inorganic silicate described in step (1) is one or more of smectite, illite and feldspar.

Preferably, the fluorescent dye described in step (1) is commercial rhodamine or solvent-based dye.

Preferably, the amount of fluorescent dye added in step (1) is 0.1-5 wt % of the inorganic silicate.

Preferably, in step (2), the mass ratio of sodium alginate to mixed powder is 1:(2-6.5).

Preferably, in step (2), the dissolving temperature of sodium alginate is 40-80° C., and the stirring time is 1-5 h.

Preferably, the mass ratio of calcium chloride anhydrous and sodium alginate added in step (3) is 1:(0.5～2.5).

Preferably, the mass ratio of sodium carbonate added in step (4) to anhydrous calcium chloride is 1: (1.1-1.3).

The invention adsorbs fluorescent dye molecules through environmentally friendly sodium alginate gel, has stronger adsorption force, and fixes the dye molecules in the gel network; then the gel layer is converted into an inorganic salt protection layer, and on the one hand, the dye is further coated Molecules, on the other hand, the inorganic salt protective layer can make the fluorescent pigment have good acid and alkali resistance and be more stable.

Sodium alginate is composed of two monomers (1,4)-β-D-mannuronic acid (M) and (1,4)-α-L-guluronic acid (G) through glycosidic bonds Unbranched block copolymers, the chain structures of these two uronic acids are very similar, only the difference in the hydroxyl position on them, but the spatial structure of their further polymerization into chains after ring formation is very different, which determines differences in their physicochemical properties. When the two monomers are linked differently, three different fragments can be formed: polymannuronic acid block (MM), polyguluronic acid block (GG), and mannuronic acid-guluronic acid Acid block (MG). When sodium alginate is in contact with a solution containing divalent cations such as Ca ²⁺ , the divalent cations will occupy these hydrophilic spaces, and the carboxyl and hydroxyl groups on the GG polyguluronic acid block in sodium alginate will Multiple oxygen atoms and these divalent cations attract each other, and the resulting chelation makes their molecular chains tightly bond and strengthen the synergy. The divalent cation and the G block form an "egg-box" structure, and finally form a three-dimensional network structure Hydrogels in which calcium chloride acts as a calcium source as a cross-linking agent. After the hydrogel is formed, sodium carbonate is added, and calcium ions attract carbonate ions to form nano-amorphous calcium carbonate in situ, and the amorphous nano-calcium carbonate ions are connected by the gel to form an inorganic salt coating layer.

Therefore, the beneficial effects of the present invention are: the fluorescent dye molecules are adsorbed by the sodium alginate gel, and the gel layer is converted into an inorganic salt protection layer, so that the fluorescent pigment is not easy to bleed, has good acid and alkali resistance, and is more stable .

Description of drawings

Fig. 1 is a real picture of the fluorescent pigment prepared in Example 1 of the present invention under a natural light source and an ultraviolet light source (the left is the natural light source, and the right is the ultraviolet light source).

Figure 2 is the dye adsorption rate at different initial dye concentrations.

FIG. 3 is the fluorescence intensity of the fluorescent pigments of Example 1 and Comparative Example 1 treated at pH=5 for 12 hours.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

Example 1:

A gel preparation method of a fluorescent pigment, comprising the following steps:

(1) 50g smectite and 0.2g rhodamine B are mixed and ground to obtain mixed powder;

(2) Dissolve 10 g of sodium alginate in 200 mL of warm water at 50°C, stir at high speed until there are no lumps in the liquid, then add the mixed powder into the slurry, and continue stirring for 2 hours to obtain a mixed slurry;

(3) adding 5.5 g of anhydrous calcium chloride to the mixed slurry while stirring, and gel flocs rapidly appear in the slurry, and continue stirring until the flocs disappear to form a uniform gel to obtain a gel intermediate;

(4) Add 5 g of sodium carbonate to the gel intermediate, the color of the solution changes, stir until the color is uniform and precipitation, wash the obtained product until there is no floating color, centrifugal drying and grinding into powder to obtain the fluorescent pigment.

Example 2:

A gel preparation method of a fluorescent pigment, comprising the following steps:

(1) 50g kaolinite and 0.5g solvent yellow 172 are mixed and ground to obtain mixed powder;

(2) Dissolve 20 g of sodium alginate in 200 mL of 50°C warm water, stir at high speed until there is no lumpy aggregate in the liquid, then add the mixed powder into the slurry, and continue stirring for 1 hour to obtain a mixed slurry;

(3) adding 11 g of anhydrous calcium chloride to the mixed slurry while stirring, gel flocs rapidly appear in the slurry, and continue stirring until the flocs disappear to form a uniform gel to obtain a gel intermediate;

(4) Add 10 g of sodium carbonate to the gel intermediate, the color of the solution changes, stir until the color is uniform and precipitation, wash the obtained product until there is no floating color, centrifugal drying and grinding into powder to obtain the fluorescent pigment.

Example 3:

A gel preparation method of a fluorescent pigment, comprising the following steps:

(1) 15g saponite, 35g montmorillonite and 0.15g rhodamine 6G are mixed and ground to obtain mixed powder;

(2) Dissolve 25 g of sodium alginate in 350 mL of warm water at 40°C, stir at high speed until there is no lumpy aggregate in the liquid, then add the mixed powder into the slurry, and continue stirring for 1 hour to obtain a mixed slurry;

(3) 6.5g of anhydrous calcium chloride was added to the mixed slurry while stirring, and gel flocs rapidly appeared in the slurry, and continued stirring until the flocs disappeared to form a uniform gel to obtain a gel intermediate;

(4) Add 6g of sodium carbonate to the gel intermediate, the color of the solution changes, stir until the color is uniform and precipitation, wash the obtained product until there is no floating color, centrifugal drying and grinding into powder to obtain the fluorescent pigment.

Example 4:

A gel preparation method of a fluorescent pigment, comprising the following steps:

(1) 50g smectite and 2.5g rhodamine B are mixed and ground to obtain mixed powder;

(2) Dissolve 10 g of sodium alginate in 200 mL of warm water at 80°C, stir at high speed until there are no lumps in the liquid, then add the mixed powder into the slurry, and continue stirring for 1 hour to obtain a mixed slurry;

(3) adding 5.5 g of anhydrous calcium chloride to the mixed slurry while stirring, and gel flocs rapidly appear in the slurry, and continue stirring until the flocs disappear to form a uniform gel to obtain a gel intermediate;

(4) Add 5 g of sodium carbonate to the gel intermediate, the color of the solution changes, stir until the color is uniform and precipitation, wash the obtained product until there is no floating color, centrifugal drying and grinding into powder to obtain the fluorescent pigment.

Example 5:

A gel preparation method of a fluorescent pigment, comprising the following steps:

(1) 25g saponite, 25g montmorillonite and 0.15g rhodamine 6G are mixed and ground to obtain mixed powder;

(2) Dissolve 25g of sodium alginate in 350mL of 50°C warm water, stir at high speed until there are no lumps in the liquid, then add the mixed powder into the slurry, and continue stirring for 5h to obtain a mixed slurry;

(3) adding 62.5g of anhydrous calcium chloride to the mixed slurry while stirring, gel flocs rapidly appear in the slurry, continue to stir until the flocs disappear, form a uniform gel, and obtain a gel intermediate;

(4) Add 60g of sodium carbonate to the gel intermediate, the color of the solution changes, stir until the color is uniform and precipitation, wash the obtained product until there is no floating color, centrifugal drying and grinding into powder to obtain the fluorescent pigment.

Example 6:

A gel preparation method of a fluorescent pigment, comprising the following steps:

(1) 50g kaolinite and 0.5g solvent yellow 172 are mixed and ground to obtain mixed powder;

(2) Dissolve 0.8 g of sodium alginate in 500 mL of warm water at 50°C, stir at high speed until there are no lumps in the liquid, then add the mixed powder into the slurry, and continue stirring for 3 hours to obtain a mixed slurry;

(3) 1.6 g of anhydrous calcium chloride was added to the mixed slurry while stirring, and gel flocs quickly appeared in the slurry, and continued stirring until the flocs disappeared, forming a uniform gel, and obtaining a gel intermediate;

(4) Add 1.5g of sodium carbonate to the gel intermediate, the color of the solution changes, stir until the color is uniform and then precipitate, wash the obtained product until there is no floating color, centrifugal drying and grinding into powder to obtain the fluorescent pigment.

Example 7:

The difference between Example 7 and Example 6 is that the mass of Solvent Yellow 172 is 1.5 g, the mass of sodium alginate is 1.32 g, and the rest are the same as in Example 6.

Example 8:

The difference between Example 8 and Example 6 is that the fluorescent dye in Example 6 is 2.38 g of Rhodamine B, and the rest are the same as those in Example 6.

Comparative Example 1:

Commercially available solvent yellow 172 fluorescent pigment.

The adsorption rate (adsorption time 6h) of the dyes in the above examples was measured, and the results are shown in Table 1 and FIG. 2 .

Table 1: Dye adsorption rates.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Dye adsorption rate (%) 88.3% 93.1% 90.5% 90.3% 95.6% 94.2% 89.9% 92%

It can be seen from Table 1 and Figure 2 that the fluorescent pigment prepared by the method of the present invention has good adsorption performance to dye, and the lower the initial concentration of dye, the higher the adsorption rate. The reason is that the higher the initial concentration of the dye, the more likely the aggregation phenomenon will occur. After aggregation, the aggregates are not easy to enter the interlayer because of space hindrance and not easy to dissociate.

The fluorescence intensity changes of the commercially available fluorescent pigments in Example 1 and Comparative Example 1 after being treated for 12 hours under the condition of pH=5 were measured, and the results are shown in FIG. 3 . It can be seen from FIG. 3 that the acid and alkali resistance of the fluorescent pigment prepared by the method of the present invention is significantly improved compared with the existing fluorescent pigment.

Claims (8)

1. a gel preparation method of fluorescent pigment, is characterized in that, comprises the steps: (1) Mix and grind inorganic silicate and fluorescent dye to obtain mixed powder; (2) adding sodium alginate into water, stirring until completely dissolved, then adding the mixed powder, and stirring evenly to obtain a mixed slurry; (3) adding anhydrous calcium chloride to the mixed slurry, stirring evenly to obtain a gel intermediate; (4) adding sodium carbonate to the gel intermediate, stirring uniformly and then precipitation, washing the obtained product until no floating color is present, and drying to obtain the fluorescent pigment. 2 . The method for preparing a fluorescent pigment gel according to claim 1 , wherein the inorganic silicate in step (1) is one of smectite, illite, and feldspar or feldspar. 3 . several. 3 . The method for preparing a fluorescent pigment gel according to claim 1 , wherein the fluorescent dye in step (1) is commercial rhodamine or solvent-based dye. 4 . 4 . The method for preparing a fluorescent pigment gel according to claim 1 , wherein the amount of fluorescent dye added in step (1) is 0.1 to 5 wt % of the inorganic silicate. 5 . 5 . The method for preparing a fluorescent pigment gel according to claim 1 , wherein the mass ratio of sodium alginate to mixed powder in step (2) is 1:(2~6.5). 6 . 6 . The method for preparing a fluorescent pigment gel according to claim 1 or 5 , wherein the dissolution temperature of sodium alginate in step (2) is 40-80° C., and the stirring time is 1-5 h. 7 . 7. The gel preparation method of a fluorescent pigment according to claim 1, wherein the mass ratio of calcium chloride anhydrous and sodium alginate added in step (3) is 1: (0.5~2.5) . 8 . The method for preparing a fluorescent pigment gel according to claim 1 , wherein the mass ratio of sodium carbonate and anhydrous calcium chloride added in step (4) is 1: (1.1-1.3). 9 .

Images