Process for preparing a dye solvent red 196 crystal transformation product

Abstract

The application discloses a preparation method of a dye solvent red 196 crystal transformation product, and comprises the following steps: mixing a wet filter cake formed by reacting solvent red 197 with concentrated hydrochloric acid with a mixed solution of an aliphatic organic solvent and water, then adding alkali liquid dropwise to perform neutralization and crystal transformation; if the pH of the filter cake is neutral or weakly alkaline after one-time alkali beating, water beating treatment is performed; if the filter cake is still acidic, the operation of alkali beating is repeated at least once until the filter cake meets the requirements; the filter cake meeting the requirements is subjected to water beating treatment for 2-3 times to obtain the dye solvent red 196 crystal transformation product. The process is simple, time-consuming is short, the obtained product is dark green, the quality is high, and the product is more suitable for silk spraying and plastic wire drawing industries.

Description

Technical Field

[0001] This invention relates to a method for preparing a solvent red 196 dye conversion product, specifically a method for preparing a solvent red 196 dye conversion product for spray dyeing of silk and plastic filaments. Background Technology

[0002] Solvent Red 196 is a fluorescent red powder with an amorphous and metastable microstructure. Its Chinese alias is Fluorescent Red BK, and its chemical formula is C. 23 H 18 N4O2, CAS number 52372-36-8, possesses excellent heat and light resistance, good migration resistance, and high coloring strength, making it recommended for coloring plastics and fibers. Solvent Red 196 is a commonly used spray dye in the silk and plastic filament drawing industries. Traditional silk dyeing uses a dye bath, which easily causes defects such as creases, abrasions, and wrinkles in the silk. A new process has been developed: dyeing is done by spraying dye solution onto the silk in its flat state using a high-pressure nozzle. PET colored with Solvent Red 196 can be drawn into filaments and then woven into fabric and clothing. The process for drawing plastic polymer materials involves first melting and mixing the plastic and Solvent Red 196 (and other colored dyes) together, then spraying the melt under pressure through a nozzle, drawing and cooling simultaneously. Both silk spray dyeing and plastic coloring and drawing processes utilize nozzles and require high dye particle size.

[0003] The particle size of ordinary red solvent red 196 currently sold on the market is generally 30-40μm. Because it is an amorphous metastable form, it is difficult to pulverize into finer particles, and secondary aggregation can occur during use. Therefore, red solvent red 196 used for silk dyeing or plastic filament spinning needs to be converted into a green fine powder before use. The purpose of conversion is to transform the red solvent red 196 from a metastable state to a stable state. After the crystal form conversion, the appearance color changes to dark green. In addition, the dark green solvent red 196 after the crystal form conversion is easier to ultrafine pulverize, resulting in finer particles, a more uniform particle size distribution, and no secondary aggregation.

[0004] Currently, the crystal transformation process for Solvent Red 196 is as follows:

[0005] First, neutralization and washing: The wet filter cake of Solvent Red 196 formed by the reaction of Solvent Red 197 with concentrated hydrochloric acid is first neutralized with sodium hydroxide solution, and then the inorganic salts in the filter cake are thoroughly washed with a large amount of soft water. This process is repeated 2-3 times, and then the cleaned filter cake is dried.

[0006] Secondly, crystallization: The dried filter cake is put into the reaction vessel, DMF solvent is added in proportion, the temperature is raised to 120-130℃ to dissolve and kept at this temperature for 3 hours, then the temperature is lowered to 60-80℃, a certain amount of methanol is added dropwise in proportion, and the temperature is kept at this temperature for 2 hours, and finally the temperature is lowered to 0±25℃.

[0007] Finally, washing and drying: the above materials are filtered, the filter cake is washed with a certain amount of methanol, then soaked and washed with a certain amount of soft water, filtered, dried, and ultra-finely pulverized to obtain the transcrystalline Solvent Red 196.

[0008] In the above-mentioned crystallization process, the wet filter cake of Solvent Red 196 has agglomeration, which causes severe adsorption and coating of hydrochloric acid. It is difficult to adjust the pH to neutral by alkali neutralization, and it is necessary to repeatedly adjust, filter and wash, which is quite complicated and tedious, and the cycle is long. Summary of the Invention

[0009] To address the shortcomings of existing solvent red 196 crystallization processes, such as cumbersome processes and long cycles, this invention provides a method for preparing solvent red 196 crystallization products. This method is simple, has a short production cycle, generates little wastewater, and produces high-quality products. When used in the silk dyeing and plastic filament drawing industries, the particle size can be pulverized to be smaller and more uniformly distributed, avoiding problems such as nozzle clogging, filament breakage, and uneven dyeing.

[0010] The specific technical solution of this invention is as follows:

[0011] A method for preparing a solvent red 196 dye conversion product, also known as a solvent red 196 conversion method, includes the following steps:

[0012] (1) Mix the wet filter cake of Solvent Red 196 with a mixture of aliphatic organic solvent-water, then add alkali solution dropwise. When the pH is 8-10, stop adding alkali solution dropwise, keep the reaction at the temperature, filter and wash with water after the reaction to obtain wet filter cake;

[0013] (2) After the heat preservation reaction in step (1) is completed, the pH of the liquid is tested. If the pH is neutral or weakly alkaline, the wet filter cake after washing in step (1) is directly put into the water pulping treatment step in step (3). If the pH is acidic, the wet filter cake after washing in step (1) is repeated at least once until the pH of the liquid after the heat preservation reaction is neutral or weakly alkaline. Then the wet filter cake after washing is put into the water pulping treatment step in step (3).

[0014] (3) The wet filter cake that meets the requirements is added to water for pulping, then filtered and washed with water;

[0015] (4) Repeat step (3) 1-2 times, and then dry the filter cake obtained by washing with water to obtain the dye solvent red 196 crystal product. The crystal product has a dark green appearance.

[0016] Furthermore, in step (1), the solvent red 196 wet filter cake is dispersed in a mixture of organic solvent and water, and then an alkaline solution is added dropwise for pulping. The alkali in the alkaline solution neutralizes the hydrochloric acid in the wet filter cake. At the same time, the solvent red 196 also undergoes a crystal transformation to form a dark green crystal.

[0017] Furthermore, in step (1), a surfactant may be added. The surfactant is added before the alkali solution is added. There are no special requirements for the mixing order of the Solvent Red 196 wet filter cake, the surfactant, and the aliphatic organic solvent-water mixture. The Solvent Red 196 wet filter cake and the aliphatic organic solvent-water mixture can be mixed first, and then the surfactant can be added. Alternatively, the surfactant and the aliphatic organic solvent-water mixture can be mixed first, and then the wet filter cake can be added. All three can be mixed simultaneously. The surfactant is an OP series product, a Tween series product, or a Span series product, preferably a Tween series product.

[0018] Further, in step (1), the aliphatic organic solvent is a low molecular weight fatty alcohol, a low molecular weight fatty acid ester, dioxane, dioxapentane, a short-chain aliphatic ketone, morpholine, ethylene glycol monoether, or ethylene glycol diether. The low molecular weight fatty alcohol is a fatty alcohol with 1-5 carbon atoms, such as methanol, ethanol, isopropanol, and butanediol. The low molecular weight fatty acid ester is a fatty acid ester with 1-5 carbon atoms, such as ethyl acetate and butyl acetate. The short-chain aliphatic ketone is an aliphatic ketone with 1-6 carbon atoms, such as acetone and methyl isobutyl ketone. The ethylene glycol monoether includes ethylene glycol monomethyl ether and ethylene glycol monoethyl ether. The ethylene glycol diether includes ethylene glycol dimethyl ether and ethylene glycol diethyl ether. Preferably, the aliphatic organic solvent is a low molecular weight fatty alcohol, more preferably methanol.

[0019] Furthermore, in step (1), the amount of surfactant used is 1%-5% of the wet filtrate weight of Solvent Red 196, preferably 2%.

[0020] Furthermore, in step (1), the mass percentage of the aliphatic organic solvent in the mixture of aliphatic organic solvent and water is 20-40%, for example 20%, 30%, 40%, and the corresponding water content is 60-80%, for example 60%, 70%, 80%.

[0021] Furthermore, in step (1), the mass ratio of the Solvent Red 196 wet filter cake to the mixture of aliphatic organic solvent and water is 1:4-8, for example, 1:4, 1:5, 1:6, 1:7, or 1:8. The solid content in the wet filter cake is generally between 30% and 60%.

[0022] Further, in step (1), the alkaline solution is an aqueous solution of a metal hydroxide, an aqueous solution of a metal carbonate, or an aqueous solution of a metal bicarbonate. The metal hydroxide includes sodium hydroxide, potassium hydroxide, etc. The metal carbonate includes sodium carbonate, potassium carbonate, etc. The metal bicarbonate includes sodium bicarbonate, potassium bicarbonate, etc. Preferably, the alkaline solution is an aqueous solution of bicarbonate.

[0023] Furthermore, in step (1), if the concentration of the alkali solution is too high, the reaction will be violent and a coating phenomenon will occur during the alkali pulping and neutralization process, which is not good. In addition, the neutralization of carbonates and bicarbonates with hydrochloric acid will produce a large number of bubbles. If the concentration is too high, there is a risk of the foam increasing and overflowing. Therefore, the concentration of the alkali solution is less than or equal to 15wt%.

[0024] Preferably, in step (1), the concentration of the alkali solution is 5wt%-15wt%, for example 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%.

[0025] Preferably, in step (1), the alkaline solution is an aqueous solution of sodium bicarbonate with a concentration of 8%-10%.

[0026] Furthermore, in step (1), there are no special requirements for the temperature of adding the alkali solution and maintaining the reaction temperature. It can be carried out at any temperature between 0-100℃, such as 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, etc. Increasing the reaction temperature is beneficial to the neutralization reaction and also to the migration of hydrochloric acid from the agglomerated material coating. From an economic point of view, the addition of the alkali solution and the neutralization reaction are carried out at 55±1℃.

[0027] Furthermore, in step (1), the addition of alkali solution and the heat preservation reaction are carried out under stirring. Stirring helps to break up the agglomerated materials in the reactor, making the reaction more uniform and complete. Preferably, the stirring speed is 200-300 rpm, for example, 200 rpm, 210 rpm, 220 rpm, 230 rpm, 240 rpm, 250 rpm, 260 rpm, 270 rpm, 280 rpm, 290 rpm, and 300 rpm.

[0028] Furthermore, in step (1), after stopping the addition of alkali solution, the reaction is kept at a constant temperature for 1-4 hours, for example, 1 hour, 2 hours, 3 hours, or 4 hours. Because hydrochloric acid may be encapsulated by the product, some hydrochloric acid may remain after the specified pH is reached, resulting in a false impression of neutralization. Therefore, it is preferable to continue stirring and keeping the reaction at a constant temperature for a period of time after the alkali solution has been added.

[0029] Furthermore, in step (1), after a heat preservation reaction, the obtained material is filtered by pressure filtration or vacuum filtration, and then washed with water to obtain a wet filter cake. The water washing is generally 1-3 times.

[0030] Furthermore, in step (2), after one heat preservation reaction, some hydrochloric acid will still remain. Therefore, it is necessary to repeat step (1) at least once to obtain a neutral or slightly alkaline wet filter cake. Under the reaction conditions described above in this invention, a suitable wet filter cake can generally be obtained by one alkali neutralization treatment or by repeating the alkali neutralization operation in step (1).

[0031] Furthermore, in step (3), the mass ratio of wet filter cake to water is 1:4-8, for example 1:4, 1:5, 1:6, 1:7, 1:8.

[0032] Furthermore, in step (3), there are no special requirements for the pulping temperature. As long as the filter cake is neutral, it can be carried out at any temperature between 0-100℃, such as 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, etc. Appropriate heating is beneficial to improving the washing efficiency, so it is preferred to pulp at 45-55℃.

[0033] Furthermore, in step (3), the pulping time is 1-4 hours, for example, 1 hour, 2 hours, 3 hours, or 4 hours.

[0034] Furthermore, in step (3), the pulping is carried out under stirring. Stirring helps to disperse the materials and makes the pulping effect better. Preferably, the stirring speed is 200-300 rpm, such as 200 rpm, 210 rpm, 220 rpm, 230 rpm, 240 rpm, 250 rpm, 260 rpm, 270 rpm, 280 rpm, 290 rpm, and 300 rpm.

[0035] The present invention has the following beneficial effects:

[0036] 1. The process of this invention is simple and quick. While adjusting the pH through alkali pulping, the crystal form is also transformed (from red to dark green crystal form), which simplifies the operation, shortens the process time, reduces wastewater, and improves production efficiency.

[0037] 2. The present invention adds a surfactant before alkaline pulping, which is beneficial to the rapid and uniform dispersion of Solvent Red 196 particles in the dispersion medium of aliphatic organic solvent-water, making pulping, neutralization and crystallization faster and easier.

[0038] 3. This invention selects a mixture of aliphatic organic solvent and water as the dispersion medium for alkali neutralization, which can deagglomerate the Solvent Red 196 filter cake, improve the dispersion uniformity of the Solvent Red 196 wet filter cake in the liquid phase, make the particles finer, weaken or eliminate the adsorption and coating effect of the Solvent Red 196 filter cake particles on hydrochloric acid, and make the alkali pulping and pH adjustment faster and more thorough, thus improving the alkali pulping efficiency.

[0039] 4. This invention transforms the metastable red solvent red 196 crystal state into a stable dark green crystal state. This crystal state is easier to ultrafine grind, with finer particle size and more uniform particle size distribution. It does not produce secondary aggregation during use. When in use, the pressure of the nozzle and plastic head of the silk spraying dyeing machine is less than 1.0MPa, resulting in smoother spraying, improving product quality and added value, and making it more suitable for the silk spraying dyeing and plastic drawing industries. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to specific embodiments, making the advantages of the present invention more apparent. It should be understood that the content therein is for illustrative purposes only and is not intended to limit the scope of protection of the present invention. Experimental methods in the following embodiments that do not specify specific conditions are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer.

[0041] Unless otherwise specified, all concentrations below are mass percentages.

[0042] In the following examples and comparative examples, the solvent Red 196 wet filter cake was purchased from a fine chemical company in Nantong, Jiangsu Province. The main components of the wet filter cake were the red solvent Red 196 and hydrochloric acid.

[0043] Example 1

[0044] The first step, the crystal transformation process

[0045] Weigh 80 g of Solvent Red 196 wet filter cake (45% solids, 36 g dry weight) into a 1000 mL four-necked reactor. Add 1.6 g of Tween 20 and 480 g of methanol-water (3:7 mass ratio) mixture. Start stirring at 260 rpm and heat in a water bath. When the temperature of the material in the reactor reaches 55±1℃, begin adding a 10% sodium bicarbonate solution dropwise, continuously monitoring the online pH meter reading. When the pH meter reading reaches 9-10, stop adding the sodium bicarbonate solution and maintain the temperature for 1 hour. Then, drop the slurry from the reactor onto pH paper. Observe that a dark green halo appears around the material. Filter the slurry, wash the filter cake with 100 mL of soft water, and repeat the washing process twice to obtain a dark green crystallized filter cake, which is then ready for the next step.

[0046] The second step is the water-based pulping and washing process.

[0047] The first-stage filter cake was placed into a 1000ml four-necked flask, 600g of soft water was added, and stirring was started at 260 rpm. A hot water bath was used to heat the mixture. When the temperature of the material inside the bath reached about 55±1℃, the mixture was kept at this temperature and stirred for 1 hour. The slurry was then filtered, and the filter cake was washed with 100ml of soft water. This washing process was repeated twice.

[0048] The third step involves placing the filter cake from the second step into a 1000ml four-necked flask and repeating the operation of the second step once. The resulting filter cake is then dried under vacuum at 105±1℃. The filter cake is then pulverized using a laboratory ultrafine pulverizer CWF300 under the following conditions: room temperature, 4500r / min, and pulverization for 8 minutes. This yields Solvent Red 196 crystallization product, which appears as a dark green fine powder.

[0049] Example 2

[0050] Solvent Red 196 crystallization product was prepared according to the operation of Example 1 above, except that methanol was replaced with ethanol and Tween 20 was replaced with OP-10.

[0051] Example 3

[0052] The Solvent Red 196 crystallization product was prepared according to the procedure in Example 1 above, except that methanol was replaced with ethylene glycol monomethyl ether, and Tween 20 was replaced with Span 20. The crystallization process required two steps to complete. The crystallization process is as follows:

[0053] Weigh 80 g of Solvent Red 196 wet filter cake (45% solids, 36 g dry weight) into a 1000 mL four-necked reactor. Add 1.6 g of Span 20 and 480 g of ethylene glycol monomethyl ether-water (3:7 mass ratio). Start stirring at 260 rpm and heat in a water bath. When the temperature of the material in the reactor reaches 55 ± 1 °C, begin adding a 10% sodium bicarbonate solution dropwise, continuously monitoring the online pH meter reading. When the pH meter reading reaches 9-10, stop adding the sodium bicarbonate solution and maintain the temperature for 1 hour. Then, drop the slurry from the reactor onto pH paper. Observe the red halo around the material. Filter the slurry, wash the filter cake with 100 mL of soft water, and repeat the washing process twice to obtain a wet filter cake.

[0054] Add the wet filter cake back into the four-necked reactor and repeat the alkaline pulping operation as described above. After pulping for 1 hour, drop the pulp onto pH test paper and observe that a dark green halo appears around the material. Filter the pulp and wash the filter cake with 100 ml of soft water. Repeat this washing process twice to obtain the wet filter cake.

[0055] Example 4

[0056] Solvent Red 196 crystal-transformed product was prepared according to the operation of Example 1 above, except that no surfactant was added and the crystal-transformation process required two steps to complete.

[0057] Comparative Example 1

[0058] The first step is the neutralization and washing process.

[0059] Add 80g of Solvent Red 196 wet filter cake (solid content 45%, dry weight 36g) to a 1000ml four-necked flask, add 480g of soft water, turn on the stirrer at 260 rpm, then heat in a water bath, add 32% liquid alkali solution dropwise at 90±1℃, stop adding liquid alkali when the online pH meter reading is 8-10, keep warm for 4 hours, filter, wash with 160ml of soft water, repeat the washing three times, then drop the last wash water onto pH test paper and observe the presence of a reddish-brown halo;

[0060] Add the washed wet filter cake back into the four-necked flask, add 600 grams of soft water, and repeat the neutralization and washing steps as described above. Then, drop the last wash water onto pH test paper and observe for a pink halo.

[0061] The washed filter cake was placed into a four-necked flask, 600 grams of soft water was added and the mixture was stirred at 90±1℃ for 1 hour. Then it was filtered and washed with 160 ml of soft water. This process was repeated twice, and the filter cake was dried.

[0062] The second step is the crystal transformation process.

[0063] The dried filter cake was put into the reaction vessel, and 240 g of DMF solvent was added in proportion. The temperature was raised to 120-130℃ to dissolve and kept at this temperature for 3 hours. Then the temperature was lowered to 60-80℃, and 960 g of methanol was slowly added dropwise in proportion over 1 hour. The temperature was kept at this temperature for 2 hours to grow crystals, and finally the temperature was slowly lowered to 0±15℃.

[0064] The third step is the washing and drying process.

[0065] The material from the second step above was filtered. The filter cake was soaked and washed with 400g of methanol, then filtered, and then soaked and washed with 400g of soft water for 2 hours. After filtration and drying, it was pulverized using a laboratory ultrafine pulverizer CWF300 under the following conditions: room temperature, 4500r / min, and 8 minutes, to obtain the crystallized Solvent Red 196.

[0066] Comparative Example 2

[0067] Commercially available red powder Solvent Red 196 was pulverized using a laboratory CWF300 ultrafine pulverizer at room temperature, 4500 r / min, for 8 minutes to obtain ultrafine pulverized, unconverted red Solvent Red 196.

[0068] Performance testing

[0069] The particle size distribution of the products prepared in the above examples and comparative examples was tested according to the laser diffraction method for particle size distribution in GB / T 19077-2016.

[0070] The products prepared in the above examples and comparative examples were used in silk spraying and dyeing, and the nozzle pressure of the machine head that successfully sprayed out the silk dyeing material was recorded.

[0071] The test results of Example 1 are shown in Table 1 below.

[0072]

[0073] The test results of Example 2 are shown in Table 2 below.

[0074]

[0075] The test results of Example 3 are shown in Table 3 below.

[0076]

[0077] The test results of Example 4 are shown in Table 4 below.

[0078]

[0079] The test results of Comparative Example 1 are shown in Table 5 below.

[0080]

[0081] The test results of Comparative Example 2 are shown in Table 6 below.

[0082]

[0083] The conductivity, intensity, and color parameters of each embodiment and comparative product were tested, as shown in Table 7 below.

[0084] The conductivity measurement method is as follows: Take 2 grams of powdered solvent dye into a 100ml beaker, add 50ml of Wahaha bottled purified water, stir and moisten with a glass rod, then place it in an ultrasonic bath for 10 minutes, take it out and filter it with filter paper, place the beaker containing the filtrate in a constant temperature water bath, keep it at a constant temperature of 25±1℃, and perform the test according to the instructions of the conductivity meter.

[0085] Intensity and chromaticity were tested in accordance with the relevant provisions of GB / T6688-2008 "Determination of Relative Intensity and Color Difference of Dyes by Instrument Method".

[0086] .

Claims

1. A process for the preparation of a dye solvent red 196 crystal transformation product, characterized by The method comprises the following steps: (1) mixing the solvent red 196 wet filter cake with a mixture of an aliphatic organic solvent and water, then adding an alkali solution dropwise, stopping the addition of the alkali solution when the pH is 8-10, and performing a heat preservation reaction, and then filtering and washing with water to obtain a wet filter cake; (2) after the heat preservation reaction in step (1) is completed, the pH of the solution is detected, if the pH is neutral or weakly alkaline, the wet filter cake after washing in step (1) is directly subjected to a water beating treatment in step (3); if the pH is acidic, the wet filter cake after washing in step (1) is subjected to the operation in step (1) repeatedly at least once until the pH of the solution after the heat preservation reaction is neutral or weakly alkaline, and then the wet filter cake after washing is subjected to the water beating treatment in step (3); (3) adding water to the wet filter cake meeting the requirements to perform a beating treatment, and then filtering and washing with water; (4) repeating the operation in step (3) for 1-2 times, and then drying the filter cake obtained by washing to obtain a solvent red 196 crystal transformation product; The aliphatic organic solvent is a fatty alcohol with 1-5 carbon atoms, a glycol monoether or a glycol diether.

2. The method of claim 1, wherein: In step (1), at least one of the following conditions is met: Condition 1: in the mixture of the aliphatic organic solvent and water, the mass percentage content of the aliphatic organic solvent is 20-40%, and the content of water is 60-80%; Condition 2: in step (1), the mass ratio of the solvent red 196 wet filter cake to the mixture of the aliphatic organic solvent and water is 1:4-8; Condition 3: in step (1), the alkali solution is a metal hydroxide aqueous solution, a metal carbonate aqueous solution or a metal bicarbonate aqueous solution; Condition 4: in step (1), the concentration of the alkali solution is less than or equal to 15wt%.

3. The method of claim 1 wherein: In step (1), a surfactant is further added, the surfactant is added before the alkali solution is added dropwise, and the surfactant is an OP series product, a Tween series product or a Span series product.

4. The method of claim 1, 2 or 3, wherein: In step (1), the addition of the alkali solution and the heat preservation reaction are performed at 0-100℃.

5. The method of claim 1, 2 or 3, wherein: In step (1), after the addition of the alkali solution is stopped, the heat preservation reaction is performed for 1-4h.

6. The method of claim 1, 2 or 3 wherein: In step (1), the addition of the alkali solution and the heat preservation reaction are performed under stirring.

7. The method of claim 6 wherein: In step (1), the stirring speed is 200-300rpm.

8. The method of claim 1 wherein: In step (3), the mass ratio of the wet filter cake to water is 1:4-8.

9. The method of claim 1 or 8, wherein: In step (3), the beating is performed at 0-100℃.

10. The method of claim 9, wherein: In step (3), the beating time is 1-4h.

11. The method of claim 1 or 8, wherein: In step (3), the beating is performed under stirring.

12. The method of claim 11 wherein: In step (3), the stirring speed is 200-300rpm.

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