Preparation method and application of super absorbent carboxymethyl cellulose material

Abstract

The invention belongs to the field of natural polymers and pharmaceutic adjuvants, and particularly relates to a preparation method and application of a high-water-absorption carboxymethyl cellulose material. The preparation method comprises the following steps: S1, mixing sodium carboxymethyl cellulose with a solvent which is selected from an acid substance / alcohol solution or an acid substance / alcohol / aqueous solution, reacting the mixed solution at the temperature of 0-60 DEG C for 1-2 hours, and filtering to obtain a solid A; s2, drying the solid A at 80-160 DEG C for 1-6 hours; s3, putting the product in S2 into an alkaline solution to react for 1-2 hours, and filtering to obtain a solid B; and S4, treating the solid B at 80-100 DEG C for 1-6 hours to obtain the super absorbent carboxymethyl cellulose material. According to the method, the super absorbent carboxymethyl cellulose material is prepared in the acid solution with extremely low concentration through the three-step process, sulfuric acid with strong water absorption does not need to be used, the process is simple, and the obtained product does not contain sulfur elements and has important practical value.

Description

Technical Field

[0001] The present invention belongs to the fields of natural polymers and pharmaceutical excipients, and particularly relates to a preparation method and application of a highly absorbent carboxymethyl cellulose material. Background Art

[0002] Highly absorbent carboxymethyl cellulose can be used as a water retaining agent in fields such as promoting long-term plant growth, slow release of fertilizers, plant protection, and desert control. Highly absorbent carboxymethyl cellulose can also be used as a disintegrant, suspending agent, and filler to improve the dissolution rate and bioavailability of drugs, and is widely used in pharmaceutical preparations.

[0003] In the currently published literature, sulfuric acid is usually used as a catalyst, and glutaraldehyde, epichlorohydrin, dicarboxylic anhydride, etc. are used as cross-linking agents to catalyze the esterification cross-linking reaction to prepare highly absorbent carboxymethyl cellulose. However, the existing preparation methods have a cumbersome process, require the use of high-concentration acids, and the prepared highly absorbent carboxymethyl cellulose not only has a high impurity content, but also contains harmful substances such as residual aldehydes and chlorohydrins. For example: in the sulfuric acid catalysis method, 4-30% sulfuric acid needs to be added to the reaction system as a catalyst, and a large amount of sulfuric acid and sulfates exist in the prepared cross-linked product. However, due to the poor permeability of the cross-linked product, even if a large amount of washing liquid is used for washing, the impurity content in the final product is still relatively high. Cross-linking agents such as glutaraldehyde and epichlorohydrin used in the cross-linking agent method will also remain in the product, affecting the product quality. Summary of the Invention

[0004] To improve the deficiencies of the existing technology, the present invention provides a preparation method and application of a highly absorbent carboxymethyl cellulose material, which can avoid using catalysts such as sulfuric acid and cross-linking agents such as glutaraldehyde, and the obtained cellulose material has a low impurity content and high product quality.

[0005] In the first aspect, the present invention provides a preparation method of a highly absorbent carboxymethyl cellulose material, and the preparation method includes the following steps:

[0006] S1. Mix sodium carboxymethyl cellulose with a solvent, the solvent is selected from an acid substance / alcohol solution or an acid substance / alcohol / water solution, react the mixed solution at a temperature of 0-60°C for 1-2 h, and filter to obtain solid A;

[0007] S2. Dry solid A at 80-160°C for 1-6 h;

[0008] S3. React the product in S2 in an alkaline solution for 1-2 h, and filter to obtain solid B;

[0009] S4. Treat solid B at 80-100°C for 1-6 h to obtain a highly absorbent carboxymethyl cellulose material.

[0010] According to an embodiment of the present invention, the degree of substitution of the sodium carboxymethyl cellulose is 0.5 to 1.5. Preferably, the degree of substitution of the sodium carboxymethyl cellulose is 0.55 to 1.00. Further, the degree of substitution of the sodium carboxymethyl cellulose is 0.65 to 1.00, such as 0.65, 0.70, 0.72, 0.75, 0.80, 0.90.

[0011] According to an embodiment of the present invention, the acid substance is selected from at least one of malic acid, tartaric acid, succinic acid, citric acid, fumaric acid, maleic acid, edetic acid, adipic acid, oxalic acid, diethylenetriaminepentaacetic acid, polyphosphoric acid, diethylenetriamine penta(methylphosphonic acid), phosphoric acid, hydrochloric acid, nitric acid, sodium hydrogen phosphate, sodium dihydrogen phosphate, potassium hydrogen phosphate, potassium dihydrogen phosphate, lactic acid, acetic acid, formic acid, propionic acid, monochloroacetic acid, trichloroacetic acid, carbon dioxide.

[0012] According to an embodiment of the present invention, the alcohol is selected from at least one of ethanol, methanol, and isopropanol.

[0013] According to an embodiment of the present invention, in the acid substance / alcohol / aqueous solution, the mass concentration of the alcohol is 50% to 98%. Preferably, the mass concentration of the alcohol is 70% to 85%, such as 50%, 60%, 70%, 80%, 90%, 95%. According to an embodiment of the present invention, in the acid substance / alcohol / aqueous solution, the mass concentration of the acid substance is 0.01% to 3.0%, such as 0.01%, 0.05%, 0.1%, 0.5%, 0.8%, 1.0%, 2.0%, 3.0%.

[0014] According to an embodiment of the present invention, in the acid substance / alcohol solution, the mass concentration of the acid substance is 0.01% to 5.0%, such as 0.01%, 0.05%, 0.1%, 0.5%, 1.0%, 3.0%, 5.0%.

[0015] According to an embodiment of the present invention, the mass ratio of the sodium carboxymethyl cellulose to the acid substance solution is 1:5 to 1:1, such as 1:5, 1:4, 1:3, 1:2, 1:1.

[0016] According to an embodiment of the present invention, the mass ratio of the sodium carboxymethyl cellulose to the solvent is 1:(2 to 8). Preferably, the mass ratio of the sodium carboxymethyl cellulose to the solvent is 1:(3 to 6), such as 1:2, 1:3, 1:5, 1:7.

[0017] According to an embodiment of the present invention, the reaction temperature in step S1 is 20 to 40 °C. Preferably, the reaction temperature in step S1 is 25 to 30 °C, such as 25 °C.

[0018] According to an embodiment of the present invention, the temperature of the drying in step S2 is 90 to 150 °C, such as 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C.

[0019] According to an embodiment of the present invention, the drying time in step S2 is 2 to 4 h, such as 2 h, 3 h, 5 h.

[0020] According to an embodiment of the present invention, the temperature of the reaction in the alkaline solution in step S3 is room temperature.

[0021] According to an embodiment of the present invention, the alkaline solution in step S3 is a saturated alkaline solution.

[0022] According to an embodiment of the present invention, the base in the alkaline solution is selected from at least one of NaHCO3, LiHCO3, and KHCO3, such as NaHCO3.

[0023] According to an embodiment of the present invention, the temperature of the treatment in step S4 is 85 to 95 °C, such as 80 °C, 90 °C.

[0024] According to an embodiment of the present invention, the treatment time in step S4 is 2 to 5 h, such as 3 h, 4 h.

[0025] In a second aspect, the present invention provides a highly absorbent carboxymethyl cellulose prepared by the above method, and the highly absorbent carboxymethyl cellulose has a fibrous microstructure with a diameter of 10 μm to 80 μm.

[0026] According to an embodiment of the present invention, the highly absorbent carboxymethyl cellulose has a fibrous microstructure with a diameter of 20 μm to 40 μm, such as 30 μm, 40 μm, 50 μm, 60 μm.

[0027] According to an embodiment of the present invention, the highly absorbent carboxymethyl cellulose has substantially as Figure 1 、 Figure 5 shown infrared spectrum.

[0028] According to an embodiment of the present invention, the highly absorbent carboxymethyl cellulose has substantially as Figure 2 、 Figure 8 shown scanning electron microscope photograph.

[0029] According to an embodiment of the present invention, the highly absorbent carboxymethyl cellulose has substantially as Figure 6 shown optical microscope photograph.

[0030] According to an embodiment of the present invention, the water absorption ratio of the highly water-absorbent carboxymethyl cellulose is 1500% to 10000%, preferably the water absorption ratio of the water-absorbent carboxymethyl cellulose is 2000% to 6000%, such as 2500%, 3000%, 3500%, 4000%, 5000%, 6000%, 6500%, 7000%.

[0031] In a third aspect, the present invention also provides an application of the above-mentioned highly water-absorbent carboxymethyl cellulose material in adhesives, thickeners, suspending agents, emulsifiers, dispersants, stabilizers, and sizing agents.

[0032] Beneficial effects

[0033] The present invention prepares a highly water-absorbent carboxymethyl cellulose material through a three-step process in an extremely low-concentration acid solution without using highly water-absorbent sulfuric acid. The process is simple, the resulting product does not contain sulfur elements, and the content of residual acid is extremely low, which has important practical value.

[0034] The highly water-absorbent carboxymethyl cellulose material prepared by the present invention has a water absorption ratio of 1500% to 10000% and has a significant water absorption effect. Description of the drawings

[0035] Figure 1 It is the infrared spectrum of the highly water-absorbent carboxymethyl cellulose powder in Example 1.

[0036] Figure 2 It is the scanning electron microscope photograph of the highly water-absorbent carboxymethyl cellulose powder in Example 1.

[0037] Figure 3 It is the water absorption photograph of the highly water-absorbent carboxymethyl cellulose powder in Example 1.

[0038] Figure 4 It is the water absorption photograph of the highly water-absorbent carboxymethyl cellulose powder in Example 2.

[0039] Figure 5 It is the infrared spectrum of the highly water-absorbent carboxymethyl cellulose powder in Example 3.

[0040] Figure 6 It is the optical microscope photograph of the highly water-absorbent carboxymethyl cellulose powder in Example 3.

[0041] Figure 7 It is the water absorption photograph of the highly water-absorbent carboxymethyl cellulose powder in Example 7.

[0042] Figure 8 It is the scanning electron microscope photograph of the highly water-absorbent carboxymethyl cellulose powder in Example 7. Detailed implementation manners

[0043] The following will further elaborate on the highly absorbent carboxymethyl cellulose powder of the present invention, its preparation method and applications in combination with specific embodiments. It should be understood that the following embodiments are only for illustrative explanation of the present invention and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope intended to be protected by the present invention.

[0044] Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.

[0045] Example 1

[0046] A preparation method of a highly absorbent carboxymethyl cellulose material, comprising the following steps:

[0047] (1) Add 1 g of sodium carboxymethyl cellulose (substitution degree 0.75) to 4 g of malic acid / ethanol / aqueous solution (malic acid concentration is 0.8 wt%, ethanol concentration is 70 wt%), stir and react at a temperature of 25 °C for 2 h, and filter to obtain solid A;

[0048] (2) Dry solid A at 140 °C for 3.5 h to obtain a dried product;

[0049] (3) Place the dried product in (2) in 3 g of saturated aqueous NaHCO3 solution, stir and react at 25 °C for 1 h, and filter to obtain solid B;

[0050] (4) Treat solid B at a temperature of 80 °C for 4 h to obtain a highly absorbent cellulose material.

[0051] See Figure 1 As shown, it is the infrared spectrum of the highly absorbent carboxymethyl cellulose powder prepared in this example. It can be seen from the figure that the stretching vibration peak of hydroxyl O-H is 3259 cm -1 , the stretching vibration peak of COONa is 1587 cm -1 and the stretching vibration peak of C-O-C is 1028 cm -1 , and the main component of the obtained material is sodium carboxymethyl cellulose.

[0052] See Figure 2 As can be seen from the figure, the highly absorbent carboxymethyl cellulose prepared in this example has a fibrous structure with a diameter of 20 μm.

[0053] See Figure 3 As shown, place 0.5 g of the highly absorbent carboxymethyl cellulose powder prepared in this example in 50 mL of water, and it can absorb water up to 15 mL, indicating that the water absorption ratio of the powder of the present invention is 3000%, and it has a significant water absorption effect.

[0054] Example 2

[0055] Preparation method of superabsorbent carboxymethyl cellulose material, comprising the following steps:

[0056] (1) Add 1 g of sodium carboxymethyl cellulose (degree of substitution 0.65) to 3 g of tartaric acid / ethanol / aqueous solution (tartaric acid concentration is 1.0 wt%, ethanol concentration is 85 wt%), stir and react at a temperature of 25 °C for 2 h, and filter to obtain solid A;

[0057] (2) Dry solid A at 140 °C for 4.5 h to obtain a dried product;

[0058] (3) Place the dried product in (2) in 6 g of saturated aqueous NaHCO3 solution, stir and react at 255 °C for 1 h, filter to obtain solid B;

[0059] (4) Treat solid B at a temperature of 100 °C for 3 h to obtain a superabsorbent cellulose material.

[0060] The superabsorbent carboxymethyl cellulose material obtained in this example is in a powder structure and has a fibrous microstructure with a diameter of 20 μm.

[0061] See Figure 4 As shown, place 1 g of the superabsorbent carboxymethyl cellulose powder prepared in this example in 50 mL of water, it can absorb water up to 29 mL, and the water absorption ratio is 2900%, indicating that the superabsorbent carboxymethyl cellulose powder prepared in this example has a significant water absorption effect.

[0062] Example 3

[0063] Preparation method of superabsorbent carboxymethyl cellulose material, comprising the following steps:

[0064] (1) Add 1 g of sodium carboxymethyl cellulose (degree of substitution 0.80) to 3 g of maleic acid / ethanol / aqueous solution (maleic acid concentration 1.5 wt%, ethanol concentration 95 wt%), stir and react at a temperature of 25 °C for 2 h, and filter to obtain solid A;

[0065] (2) Treat solid A at 140 °C for 3 h to obtain a dried product;

[0066] (3) Place the dried product in (2) in 5 g of saturated aqueous NaHCO3 solution, stir and react at 25 °C for 1 h, filter to obtain solid B;

[0067] (4) Treat solid B at 100 °C for 3 h to obtain a superabsorbent carboxymethyl cellulose material.

[0068] See Figure 5 As shown, it is the infrared spectrum of the superabsorbent carboxymethyl cellulose powder prepared in this example. It can be seen from the figure that the stretching vibration peak of hydroxyl O-H is 3213 cm-1 , the stretching vibration peak of COONa is at 1582 cm -1 and the stretching vibration peak of C-O-C is at 1018 cm -1 , and the main component of the obtained material is sodium carboxymethyl cellulose.

[0069] See Figure 6 As can be seen from the figure shown, the highly absorbent carboxymethyl cellulose prepared in this example has a fibrous microstructure with a diameter of 20 μm.

[0070] Put 0.5 g of the highly absorbent carboxymethyl cellulose powder prepared in this example into 50 mL of water, and it can absorb water up to 22.5 mL, indicating that the water absorption ratio of the highly absorbent carboxymethyl cellulose powder in this example is 4500%, showing a significant water absorption effect.

[0071] Example 4

[0072] A preparation method of a highly absorbent cellulose material, comprising the following steps:

[0073] (1) Add 1 g of sodium carboxymethyl cellulose (degree of substitution 0.70) to 5 g of sodium dihydrogen phosphate / ethanol / aqueous solution (the concentration of sodium dihydrogen phosphate is 0.7 wt%, and the concentration of ethanol is 60 wt%), and stir and react at a temperature of 25 °C for 2 h, then filter to obtain solid A;

[0074] (2) Treat solid A at 140 °C for 2 h to obtain a dried product;

[0075] (3) Place the dried product in (2) in 5 g of saturated aqueous solution of NaHCO3, stir and react at 25 °C for 1 h, and after filtration, obtain solid B;

[0076] (4) Treat solid B at 90 °C for 3 h to obtain a highly absorbent carboxymethyl cellulose material.

[0077] The highly absorbent carboxymethyl cellulose powder obtained in this example has a fibrous microstructure with a diameter of 20 μm.

[0078] The water absorption ratio of the highly absorbent carboxymethyl cellulose powder obtained in this example is 3000%, showing a significant water absorption effect.

[0079] Example 5

[0080] A preparation method of a highly absorbent carboxymethyl cellulose material, comprising the following steps:

[0081] (1) Add 1 g of sodium carboxymethyl cellulose (degree of substitution 0.72) to 5 g of lactic acid / ethanol solution (the concentration of lactic acid is 1.5 wt%, and the concentration of ethanol is 98.5 wt%), and stir and react at a temperature of 25 °C for 2 h, then filter to obtain solid A;

[0082] (2) Treat solid A at 120 °C for 6 h to obtain a dried product;

[0083] (3) Place the dried product in (2) into 5 g of a saturated aqueous solution of NaHCO3, stir and react at 25 °C for 1 h, and after filtration, obtain solid B;

[0084] (4) Treat solid B at 80 °C for 3 h to obtain a superabsorbent carboxymethyl cellulose material.

[0085] The superabsorbent carboxymethyl cellulose powder obtained in this example has a fibrous microstructure with a diameter of 10 μm.

[0086] The water absorption ratio of the superabsorbent carboxymethyl cellulose powder obtained in this example is 7000%, showing a significant water absorption effect.

[0087] Example 6

[0088] A method for preparing a superabsorbent carboxymethyl cellulose material, comprising the following steps:

[0089] (1) Add 1 g of sodium carboxymethyl cellulose (degree of substitution 0.70) to 5 g of a hydrochloric acid / ethanol / water solution (hydrochloric acid concentration is 0.08 wt%, ethanol concentration is 80 wt%), introduce CO2, stir at a temperature of 25 °C for 2 h, and filter to obtain solid A;

[0090] (2) Treat solid A at 150 °C for 2 h to obtain a dried product;

[0091] (3) Place the dried product in (2) into 5 g of a saturated aqueous solution of NaHCO3, stir and react at 25 °C for 1 h, and after filtration, obtain solid B;

[0092] (4) Treat solid B at 80 °C for 3 h to obtain a superabsorbent carboxymethyl cellulose material.

[0093] The superabsorbent carboxymethyl cellulose powder obtained in this example has a fibrous microstructure with a diameter of 10 μm.

[0094] The water absorption ratio of the superabsorbent carboxymethyl cellulose powder obtained in this example is 4000%, showing a significant water absorption effect.

[0095] Example 7

[0096] A method for preparing a superabsorbent carboxymethyl cellulose material, comprising the following steps:

[0097] (1) Add 1 g of sodium carboxymethyl cellulose (degree of substitution 0.70) to 3 g of an oxalic acid / ethanol solution (oxalic acid concentration is 2.0 wt%, ethanol concentration is 98.0 wt%), stir and react at 25 °C for 2 h, and filter to obtain solid A;

[0098] (2) Treat solid A at 140 °C for 4 h to obtain a dried product;

[0099] (3) Place the dried product in step (2) in 5 g of a saturated aqueous solution of KHCO₃, stir and react at 25 °C for 1 h, and after filtration, obtain solid B;

[0100] (4) Treat solid B at 80 °C for 4 h to obtain a superabsorbent carboxymethyl cellulose material.

[0101] See Figure 7 As shown, place 0.5 g of the powder in 50 mL of water, which can absorb water up to 14 mL, and the water absorption ratio is 2800%, indicating that the superabsorbent carboxymethyl cellulose powder of the present invention has a significant water absorption effect.

[0102] See Figure 8 As shown, the superabsorbent carboxymethyl cellulose powder obtained in this example has a fibrous microstructure with a diameter of 20 μm.

[0103] Example 8

[0104] A method for preparing a superabsorbent carboxymethyl cellulose material, comprising the following steps:

[0105] (1) Add 1 g of sodium carboxymethyl cellulose (substitution degree 0.75) to 4 g of a citric acid / ethanol / aqueous solution (citric acid concentration 0.6 wt%, ethanol concentration 85 wt%), stir at 25 °C for 2 h, and filter to obtain solid A;

[0106] (2) Treat solid A at 160 °C for 2.5 h to obtain a dried product;

[0107] (3) Place the dried product in step (2) in 4 g of a saturated aqueous solution of KHCO₃, stir at 25 °C for 1 h, and then filter to obtain solid B;

[0108] (4) Dry-treat solid B at 80 °C for 4 h to obtain a powdery superabsorbent carboxymethyl cellulose material.

[0109] Place 0.6 g of the superabsorbent cellulose material powder prepared in this example in 50 mL of water, which can absorb water up to 30 mL, and the water absorption ratio is 5000%, indicating that the powder of the present invention has a significant water absorption effect.

[0110] The above has exemplarily described the specific implementation manners of the present invention through examples. However, the protection scope of the present invention is not limited to the above exemplary implementation manners. Any modifications, equivalent replacements, improvements, etc. made by those skilled in the art within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A preparation method of a highly water-absorbent carboxymethyl cellulose material, characterized in that, The preparation method comprises the following steps: S1. Mix sodium carboxymethyl cellulose with a solvent, where the solvent is selected from an acid substance / alcohol solution or an acid substance / alcohol / water solution. React the mixture at a temperature of 0 - 60°C for 1 - 2 h, and then filter to obtain solid A; S2. Dry solid A at 80 - 160°C for 1 - 6 h; S3. React the product in S2 in an alkaline solution for 1 - 2 h, and then filter to obtain solid B; S4. Treat solid B at 80 - 100°C for 1 - 6 h to obtain a superabsorbent sodium carboxymethyl cellulose material.

2. The preparation method according to claim 1, characterized in that, The degree of substitution of the sodium carboxymethyl cellulose is 0.5 - 1.

5. Preferably, the acid substance is selected from at least one of malic acid, tartaric acid, succinic acid, citric acid, fumaric acid, maleic acid, edetic acid, adipic acid, oxalic acid, diethylenetriaminepentaacetic acid, polyphosphoric acid, diethylenetriamine penta(methylphosphonic acid), phosphoric acid, hydrochloric acid, nitric acid, sodium hydrogen phosphate, sodium dihydrogen phosphate, potassium hydrogen phosphate, potassium dihydrogen phosphate, lactic acid, acetic acid, formic acid, propionic acid, monochloroacetic acid, trichloroacetic acid, carbon dioxide. Preferably, the alcohol is selected from at least one of ethanol, methanol, and isopropanol.

3. The preparation method according to claim 1, characterized in that, In the acid substance / alcohol / water solution, the mass concentration of the alcohol is 50% - 98%; the mass concentration of the acid substance is 0.01% - 3.0%. Preferably, in the acid substance / alcohol solution, the mass concentration of the acid substance is 0.01% - 5.0%.

4. The preparation method according to any one of claims 1-3, characterized in that, The mass ratio of the sodium carboxymethyl cellulose to the acid substance solution is 1:5 - 1:1, and the mass ratio of the sodium carboxymethyl cellulose to the solvent is 1:(2 - 8).

5. The preparation method according to any one of claims 1-3, characterized in that, The reaction temperature in step S1 is 20 - 40°C; Preferably, the drying temperature in step S2 is 100 - 150°C, and the drying time in step S2 is 2 - 4 h.

6. The preparation method according to any one of claims 1-3, characterized in that, The treatment temperature in step S3 is 85 - 95°C, and the treatment time in step S3 is 2 - 5 h; Preferably, in step S3, the alkaline solution is selected from a saturated weak alkaline solution, and the base is selected from at least one of NaHCO3, LiHCO3, and KHCO3.

7. A superabsorbent carboxymethyl cellulose prepared by the method according to any one of claims 1-5, characterized in that, The superabsorbent sodium carboxymethyl cellulose has a fibrous microstructure with a diameter of 10 μm - 80 μm.

8. The superabsorbent carboxymethyl cellulose according to claim 7, wherein The superabsorbent sodium carboxymethyl cellulose has an infrared spectrum as shown in Figures 1 and 5. Preferably, the superabsorbent sodium carboxymethyl cellulose has scanning electron microscope photos as shown in Figures 2 and 8. Preferably, the superabsorbent sodium carboxymethyl cellulose has an optical microscope photo as shown in Figure 6.

9. The superabsorbent carboxymethyl cellulose according to claim 7 or 8, characterized in that, The water absorption ratio of the superabsorbent sodium carboxymethyl cellulose is 1500% - 10000%, and preferably the water absorption ratio of the superabsorbent sodium carboxymethyl cellulose is 2000% - 6000%.

10. Use of the superabsorbent sodium carboxymethyl cellulose material prepared by the method according to any one of claims 1 - 6 or the superabsorbent sodium carboxymethyl cellulose material according to any one of claims 7 - 9 in adhesives, thickeners, suspending agents, emulsifiers, dispersants, stabilizers, and sizing agents.

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