A nano calcium carbonate modifier and a nano calcium carbonate modification method thereof

Abstract

The application belongs to the technical field of nano calcium carbonate preparation, and particularly relates to a nano calcium carbonate modifier and a modification method of nano calcium carbonate. The nano calcium carbonate modifier provided by the application comprises the following raw materials in parts by weight: component A: 70-95 parts, and component B: 5-25 parts. The component A is at least one selected from citric acid, sodium citrate, lactic acid, calcium lactate, malic acid, tartaric acid, succinic acid and at least one salt formed by the above acids. The component B is selected from sodium octenyl succinate starch, pectin, xanthan gum, gum arabic and inulin. The nano calcium carbonate modifier provided by the application can ensure the food safety of the end product, and the calcium carbonate modified by the modifier has good dispersibility in the aqueous system.

Description

Technical Field

[0001] This invention belongs to the field of nano-calcium carbonate preparation technology, specifically relating to a nano-calcium carbonate modifier and a method for modifying nano-calcium carbonate. Background Technology

[0002] Due to their small particle size and large specific surface area, nano-calcium carbonate exhibits significant changes in its surface electronic and crystal structures. These changes result in a series of unique physical effects, including small size effects, surface effects, macroscopic quantum tunneling effects, and quantum size effects, leading to special properties such as microwave absorption, reinforcing properties, and thixotropy. Currently, nano-calcium carbonate is primarily used in the plastics, rubber, automotive primers, and coatings industries, mainly serving conventional functions such as filling and increasing volume, and reducing costs. Simultaneously, it can effectively improve the mechanical properties of products, such as enhancing tensile strength, flexural strength, toughness, and wear resistance. In the food industry, nano-calcium carbonate (CaCO3), due to its high specific surface area, high purity, good biocompatibility, and low cost, can also be used as a calcium fortifier, anti-caking agent, and acidity regulator, and its nanoscale size holds promise for improving bioavailability.

[0003] However, in practical applications, nano-calcium carbonate particles have high surface energy, making them prone to aggregation and difficult to disperse uniformly in food matrices (such as water, oil, and protein systems), thus affecting functionality and taste. Therefore, to improve the dispersibility of nano-calcium carbonate, it needs to be modified. However, many industrial nano-calcium carbonate modifiers (such as aluminates, titanates, and some synthetic polymers) do not meet food-grade safety standards and cannot be used in food. Therefore, it is essential to develop a food-safe nano-calcium carbonate modifier. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of existing nano-calcium carbonate modifiers, which cannot effectively improve the dispersibility of nano-calcium carbonate in water and whose raw materials cannot be used in food, and thus provide a nano-calcium carbonate modifier and a method for modifying nano-calcium carbonate.

[0005] A nano-calcium carbonate modifier comprises the following raw materials in parts by weight: Component A: 70-95 parts; Component B: 5-25 parts; Component A is selected from at least one of citric acid, sodium citrate, lactic acid, calcium lactate, malic acid, tartaric acid, succinic acid, fumaric acid, or at least one of the salts formed from the above acids. Component B is selected from at least one of sodium octenyl succinate starch, pectin, xanthan gum, gum arabic, and inulin.

[0006] In an optional embodiment, it further includes component C: 0.01-10 parts; said component C is selected from at least one of sucrose fatty acid esters, lecithin, and polyglycerol fatty acid esters.

[0007] In one optional embodiment, the nano-calcium carbonate modifier comprises the following raw materials in parts by weight: Component A: 70-95 parts, Component B: 5-25 parts; Component A is sodium citrate and lactic acid; Component B is sodium octenyl succinate starch.

[0008] In one optional embodiment, the nano-calcium carbonate modifier comprises the following raw materials in parts by weight: Component A: 70-95 parts, Component B: 5-25 parts, Component C: 0.01-10 parts; Component A is sodium citrate and lactic acid; Component B is sodium octenyl succinate starch; Component C is sucrose fatty acid ester.

[0009] In one optional embodiment, the sucrose fatty acid ester is a sucrose fatty acid ester with an HLB value greater than 10.

[0010] This invention also provides a method for modifying nano-calcium carbonate, comprising the following steps: 1) Modifier preparation: Mix the raw materials of the above-mentioned nano-calcium carbonate modifier evenly to obtain the modifier; 2) Mix and stir the nano-calcium carbonate with the modifier, let it stand to mature, cool it and then sieve it to obtain modified calcium carbonate.

[0011] In one alternative embodiment, the mass ratio of nano-calcium carbonate to modifier in step 2) is 100:(1.5-8).

[0012] In one alternative embodiment, the average particle size of the nano-calcium carbonate is no greater than 100 nm.

[0013] In one optional embodiment, the mixing temperature in step 2) is 60-85℃, the rotation speed is 800-1500rpm, and the time is 15-40min.

[0014] In one optional embodiment, the static curing temperature is 40-60℃, and the static curing time is 1-3 hours.

[0015] The technical solution of this invention has the following advantages: The nano-calcium carbonate modifier provided by this invention uses raw materials that are food additives or recognized as safe substances (GRAS) permitted by national standards, ensuring the food safety of the end product. Furthermore, the calcium carbonate modified with the modifier of this invention exhibits good dispersibility in aqueous systems. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a process flow diagram of the modification method in Embodiment 1 of the present invention.

[0018] Figure 2 The image shows the SEM images of nano-calcium carbonate before modification in Example 1, where (a) and (b) represent spectra at different magnifications.

[0019] Figure 3 The image shows the SEM images of the modified nano-calcium carbonate from Example 1, where (a) and (b) represent spectra at different magnifications. Detailed Implementation

[0020] The following embodiments are provided to further understand the present invention and are not limited to the preferred embodiments described herein, nor do they constitute a limitation on the scope of protection of the present invention.

[0021] Experimental steps or conditions not specified in the following embodiments of this invention can be implemented according to conventional experimental steps and conditions used in existing literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagents or instruments.

[0022] In practical applications, nano-calcium carbonate particles have high surface energy, making them prone to aggregation and difficult to disperse uniformly in food matrices (such as water, oil, and protein systems), thus affecting functionality and taste. Therefore, to improve the dispersibility of nano-calcium carbonate, modification is necessary. However, many industrial nano-calcium carbonate modifiers (such as aluminates, titanates, and some synthetic polymers) do not meet food-grade safety standards and cannot be used in food. Therefore, developing a food-safe nano-calcium carbonate modifier is essential.

[0023] This invention provides a nano-calcium carbonate modifier, comprising the following raw materials in parts by weight: Component A: 70-95 parts; Component B: 5-25 parts; Component A is selected from at least one of citric acid, sodium citrate, lactic acid, calcium lactate, malic acid, tartaric acid, succinic acid, fumaric acid, or at least one of the salts formed from the above acids. Component B is selected from at least one of sodium octenyl succinate starch, pectin, xanthan gum, gum arabic, and inulin.

[0024] The nano-calcium carbonate modifier provided by this invention uses raw materials that are food additives or recognized as safe substances (GRAS) permitted by national standards, ensuring the food safety of the end product. Furthermore, the calcium carbonate modified with the modifier of this invention exhibits good dispersibility in aqueous systems.

[0025] Furthermore, the modifier provided by this invention, after reasonable compounding, allows the modified nano-calcium carbonate to disperse rapidly in aqueous systems, protein solutions, and syrups to form a stable suspension. Through composite design, the product can be stable in hydrophilic environments while also partially penetrating into hydrophobic phases via interface modifiers, making it suitable for complex food systems such as beverages, yogurt, baking oils, and nutrition bars. It also improves the texture by effectively masking the "gritty" feel of nanoparticles, giving food a smooth and delicate texture; sodium citrate and other additives may also provide a slight buffering flavor. The process is green and efficient: employing a semi-dry process, there is no wastewater discharge, low energy consumption, and the process is simple and easy to industrialize. The entire process is carried out under mild conditions, avoiding the destruction of nutrients. The modified layer is firmly bonded, and the modified product exhibits good stability under dry storage at room temperature, and is not prone to re-agglomeration due to moisture absorption or storage.

[0026] In an optional embodiment, it further includes component C: 0.01-10 parts; said component C is selected from at least one of sucrose fatty acid esters, lecithin, and polyglycerol fatty acid esters.

[0027] In one optional embodiment, the nano-calcium carbonate modifier comprises the following raw materials in parts by weight: component A: 70-95 parts, component B: 5-25 parts; wherein component A is sodium citrate and lactic acid; and component B is sodium octenyl succinate starch. This invention uses sodium citrate, lactic acid, and sodium octenyl succinate starch as raw materials. The carboxyl groups interact strongly with calcium ions on the surface of calcium carbonate to form a robust adsorption layer, providing steric hindrance and electrostatic repulsion. The hydrophilic hydroxyl groups (-OH) face outward, directly enhancing surface hydrophilicity and wettability. The hydroxyl groups of lactic acid form intermolecular hydrogen bonds with water molecules and the hydroxyl groups of sodium octenyl succinate starch, acting as an inorganic-organic interface bridge to enhance the adhesion of the modified layer. Sodium octenyl succinate starch can provide long-chain steric hindrance to prevent particles from approaching each other. The starch backbone forms multi-point hydrogen bond adsorption with the hydroxyl groups on the surface of calcium carbonate, and the octenyl side chains extend outward to form a steric hindrance layer. The polymer chains fully swell and extend in water, generating an entropy repulsion effect and improving dispersion stability. This invention uses a combination of sodium citrate, lactic acid, and sodium octenyl succinate starch, which work synergistically to achieve a significant improvement in water dispersibility.

[0028] In one optional embodiment, when component A is sodium citrate and lactic acid, the mass ratio of sodium citrate to lactic acid is (3-10):1.

[0029] In one optional embodiment, the nano-calcium carbonate modifier comprises the following raw materials in parts by weight: Component A: 70-95 parts, Component B: 5-25 parts, Component C: 0.01-10 parts; Component A is sodium citrate and lactic acid; Component B is sodium octenyl succinate starch; Component C is sucrose fatty acid ester. This invention further adds sucrose fatty acid ester, lecithin, and polyglycerol fatty acid ester to the above components. In particular, the sucrose fatty acid ester can further reduce interfacial energy and improve particle distribution at the interface.

[0030] In one optional embodiment, the sucrose fatty acid ester is a sucrose fatty acid ester with an HLB value greater than 10. Optionally, the sucrose fatty acid ester is a sucrose fatty acid ester with an HLB value of 11-20.

[0031] This invention also provides a method for modifying nano-calcium carbonate, comprising the following steps: 1) Modifier preparation: Mix the raw materials of the above-mentioned nano-calcium carbonate modifier evenly to obtain the modifier; 2) Mix and stir the nano-calcium carbonate with the modifier, let it stand to mature, cool it and then sieve it to obtain modified calcium carbonate.

[0032] In one optional embodiment, the mass ratio of nano-calcium carbonate to modifier in step 2) is 100:(1.5-8). Preferably, the mass ratio of nano-calcium carbonate to modifier is 100:(3-5), and exemplaryly, the mass ratio of nano-calcium carbonate to modifier is 100:3, 100:4, or 100:5.

[0033] In one optional embodiment, the average particle size of the nano-calcium carbonate is no greater than 100 nm. Optionally, the average particle size of the nano-calcium carbonate is 50-100 nm.

[0034] In one alternative embodiment, the nano-calcium carbonate is food grade and needs to be dried to remove free moisture before being mixed with the modifier, for example, by vacuum drying at 100-120°C for 2-4 hours.

[0035] In one optional embodiment, the mixing and stirring temperature in step 2) is 60-85℃, the rotation speed is 800-1500 rpm, and the time is 15-40 min. During this process, mechanical force activates the surface of calcium carbonate particles, while heat causes the modifier to melt or soften, resulting in chemical adsorption and physical coating on its surface.

[0036] In one optional embodiment, the static curing temperature is 40-60℃, and the static curing time is 1-3 hours. This curing treatment makes the coating layer more complete and stable.

[0037] In one alternative embodiment, the product is cooled and then sieved, optionally through a 200-mesh sieve, to remove any trace amounts of large agglomerates that may form, resulting in a final product with good flowability, which is then packaged in a dry environment.

[0038] In an optional embodiment, step 1) involves preparing the modifier by mixing sodium octenyl succinate starch and deionized water to prepare a solution with a mass concentration of 8-15%. The solution is stirred at 50-65°C for 5-20 minutes, then cooled to 35-45°C. Sodium citrate is added, and the mixture is stirred at 300-400 rpm for 10-20 minutes. The solution is then vacuum dried at 60-70°C for 30-60 minutes, pulverized, and sieved. Finally, it is mixed uniformly with lactic acid to obtain the modifier. In this invention, before mixing with lactic acid, sodium octenyl succinate starch and sodium citrate are first mixed in water. Sodium citrate provides a uniform negative charge environment, allowing sufficient intermolecular repulsion between sodium octenyl succinate starch molecules, preventing entanglement and agglomeration. The mixture of these two modifiers, after drying, is then mixed with lactic acid to further improve water dispersibility. Example 1

[0039] This embodiment provides a nano-calcium carbonate modifier, comprising the following raw materials in parts by weight: 70 parts of food-grade sodium citrate, 15 parts of lactic acid, and 15 parts of sodium octenyl succinate starch; This embodiment also provides a method for modifying nano-calcium carbonate, including the following steps: 1) Preparation of modifier: Weigh the above-mentioned raw materials, mix them evenly to obtain the modifier; 2) Take 1000g of dried food-grade nano calcium carbonate (average particle size 80nm) and 35g of the above modifier, add them to a high-speed mixer preheated to 70℃, stir at 1200rpm for 25min at 70℃, after discharge transfer to a sealed container and let stand and mature at 50℃ for 2h, after cooling pass through a 200-mesh sieve to obtain the modified calcium carbonate product. Example 2

[0040] This embodiment provides a nano-calcium carbonate modifier, comprising the following raw materials in parts by weight: 85 parts of food-grade sodium citrate and 15 parts of sodium octenyl succinate starch; This embodiment also provides a method for modifying nano-calcium carbonate, including the following steps: 1) Preparation of modifier: Weigh the above-mentioned raw materials, mix them evenly to obtain the modifier; 2) Take 1000g of dried food-grade nano calcium carbonate (average particle size 80nm) and 35g of the above modifier, add them to a high-speed mixer preheated to 70℃, stir at 1200rpm for 25min at 70℃, after discharge transfer to a sealed container and let stand and mature at 50℃ for 2h, after cooling pass through a 200-mesh sieve to obtain the modified calcium carbonate product. Example 3

[0041] This embodiment provides a nano-calcium carbonate modifier, comprising the following raw materials in parts by weight: 70 parts of food-grade sodium citrate, 15 parts of tartaric acid, and 15 parts of sodium octenyl succinate starch; This embodiment also provides a method for modifying nano-calcium carbonate, including the following steps: 1) Preparation of modifier: Weigh the above-mentioned raw materials, mix them evenly to obtain the modifier; 2) Take 1000g of dried food-grade nano calcium carbonate (average particle size 80nm) and 35g of the above modifier, add them to a high-speed mixer preheated to 70℃, stir at 1200rpm for 25min at 70℃, after discharge transfer to a sealed container and let stand and mature at 50℃ for 2h, after cooling pass through a 200-mesh sieve to obtain the modified calcium carbonate product. Example 4

[0042] This embodiment provides a nano-calcium carbonate modifier, comprising the following raw materials in parts by weight: 70 parts of food-grade sodium citrate, 15 parts of lactic acid, and 15 parts of pectin; This embodiment also provides a method for modifying nano-calcium carbonate, including the following steps: 1) Preparation of modifier: Weigh the above-mentioned raw materials, mix them evenly to obtain the modifier; 2) Take 1000g of dried food-grade nano calcium carbonate (average particle size 80nm) and 35g of the above modifier, add them to a high-speed mixer preheated to 70℃, stir at 1200rpm for 25min at 70℃, after discharge transfer to a sealed container and let stand and mature at 50℃ for 2h, after cooling pass through a 200-mesh sieve to obtain the modified calcium carbonate product. Example 5

[0043] This embodiment provides a nano-calcium carbonate modifier, comprising the following raw materials in parts by weight: 85 parts calcium lactate, 15 parts sodium octenyl succinate starch; This embodiment also provides a method for modifying nano-calcium carbonate, including the following steps: 1) Preparation of modifier: Weigh the above-mentioned raw materials, mix them evenly to obtain the modifier; 2) Take 1000g of dried food-grade nano calcium carbonate (average particle size 80nm) and 35g of the above modifier, add them to a high-speed mixer preheated to 70℃, stir at 1200rpm for 25min at 70℃, after discharge transfer to a sealed container and let stand and mature at 50℃ for 2h, after cooling pass through a 200-mesh sieve to obtain the modified calcium carbonate product. Example 6

[0044] This embodiment provides a nano-calcium carbonate modifier, comprising the following raw materials in parts by weight: 70 parts of food-grade sodium citrate, 15 parts of lactic acid, 12 parts of sodium octenyl succinate starch, and 3 parts of sucrose fatty acid ester with HLB=15. This embodiment also provides a method for modifying nano-calcium carbonate, including the following steps: 1) Preparation of modifier: Weigh the above-mentioned raw materials, mix them evenly to obtain the modifier; 2) Take 1000g of dried food-grade nano calcium carbonate (average particle size 80nm) and 35g of the above modifier, add them to a high-speed mixer preheated to 70℃, stir at 1200rpm for 25min at 70℃, after discharge transfer to a sealed container and let stand and mature at 50℃ for 2h, after cooling pass through a 200-mesh sieve to obtain the modified calcium carbonate product. Example 7

[0045] This embodiment provides a nano-calcium carbonate modifier, comprising the following raw materials in parts by weight: 70 parts of food-grade sodium citrate, 15 parts of lactic acid, and 15 parts of sodium octenyl succinate starch; This embodiment also provides a method for modifying nano-calcium carbonate, including the following steps: 1) Preparation of modifier: Sodium octenyl succinate starch and deionized water were mixed to prepare a 10% (w / w) solution. The solution was stirred at 60°C for 10 min, then cooled to 40°C, sodium citrate was added, and the mixture was stirred at 300 rpm for 15 min. The solution was then vacuum dried at 60°C for 60 min, pulverized and sieved, and then mixed evenly with lactic acid to obtain the modifier. 2) Take 1000g of dried food-grade nano calcium carbonate (average particle size 80nm) and 35g of the above modifier, add them to a high-speed mixer preheated to 70℃, stir at 1200rpm for 25min at 70℃, after discharge transfer to a sealed container and let stand and mature at 50℃ for 2h, after cooling pass through a 200-mesh sieve to obtain the modified calcium carbonate product. Example 8

[0046] This embodiment provides a nano-calcium carbonate modifier, comprising the following raw materials in parts by weight: 90 parts calcium lactate, 10 parts pectin; This embodiment also provides a method for modifying nano-calcium carbonate, including the following steps: 1) Preparation of modifier: Weigh the above-mentioned raw materials, mix them evenly to obtain the modifier; 2) Take 1000g of dried food-grade nano calcium carbonate (average particle size 80nm) and 30g of the above modifier, add them to a high-speed mixer preheated to 60℃, stir at 1000rpm for 40min at 60℃, after discharge transfer to a sealed container and let stand and mature at 40℃ for 3h, cool and pass through a 200-mesh sieve to obtain the modified calcium carbonate product.

[0047] Comparative Example 1 This comparative example provides a nano-calcium carbonate modifier and a method for modifying nano-calcium carbonate. The difference between this example and Example 1 is that the modifier is a raw material in the following parts by weight: 85 parts of food-grade sodium citrate and 15 parts of lactic acid.

[0048] Comparative Example 2 This comparative example provides a nano-calcium carbonate modifier and a method for modifying nano-calcium carbonate. The difference between this example and Example 1 is that the modifier is the following raw material in parts by weight: 100 parts of food-grade sodium citrate.

[0049] Test Example 1 The dispersibility of the modified calcium carbonate prepared in Examples 1-8 and Comparative Examples 1-2 in water was tested respectively. The test method is as follows: Weigh 1g of the product to be tested, add it to 100mL of deionized water (the deionized water is placed in a graduated cylinder in advance), stir magnetically for 2min to form a uniform suspension (record the volume as V). 总 After standing for 3 hours, the sediment layer separates into layers, and the volume of the sediment layer is measured as V. 沉 Settlement volume (%) = V 沉 / V 总 *100%, the test results are shown in Table 1.

[0050] Table 1 Example 1 5.4 Example 2 10.8 Example 3 7.6 Example 4 8.7 Example 5 13.2 Example 6 3.9 Example 7 4.4 Example 8 14.9 Comparative Example 1 15.8 Comparative Example 2 17.3 Obviously, those skilled in the art can make other modifications based on the above embodiments, and the obvious modifications therefrom are still within the protection scope of this invention.

Claims

1. A nano-calcium carbonate modifier, characterized in that, The ingredients include the following parts by weight: Component A: 70-95 parts; Component B: 5-25 parts; Component A is selected from at least one of citric acid, sodium citrate, lactic acid, calcium lactate, malic acid, tartaric acid, succinic acid, fumaric acid, or at least one of the salts formed from the above acids. Component B is selected from at least one of sodium octenyl succinate starch, pectin, xanthan gum, gum arabic, and inulin.

2. The nano-calcium carbonate modifier according to claim 1, characterized in that, It also includes component C: 0.01-10 parts; component C is selected from at least one of sucrose fatty acid esters, lecithin, and polyglycerol fatty acid esters.

3. The nano-calcium carbonate modifier according to claim 1, characterized in that, The nano-calcium carbonate modifier comprises the following raw materials in parts by weight: Component A: 70-95 parts, Component B: 5-25 parts; Component A is sodium citrate and lactic acid; Component B is sodium octenyl succinate starch.

4. The nano-calcium carbonate modifier according to claim 2, characterized in that, The nano-calcium carbonate modifier comprises the following raw materials in parts by weight: Component A: 70-95 parts, Component B: 5-25 parts, Component C: 0.01-10 parts; Component A is sodium citrate and lactic acid; Component B is sodium octenyl succinate starch; Component C is sucrose fatty acid ester.

5. The nano-calcium carbonate modifier according to claim 4, characterized in that, The sucrose fatty acid ester is a sucrose fatty acid ester with an HLB value greater than 10.

6. A method for modifying nano-calcium carbonate, characterized in that, Includes the following steps: 1) Preparation of modifier: Mix the raw materials of the nano-calcium carbonate modifier according to any one of claims 1-5 evenly to obtain the modifier; 2) Mix and stir the nano-calcium carbonate with the modifier, let it stand to mature, cool it and then sieve it to obtain modified calcium carbonate.

7. The method for modifying nano-calcium carbonate according to claim 6, characterized in that, In step 2), the mass ratio of nano-calcium carbonate to modifier is 100:(1.5-8).

8. The method for modifying nano-calcium carbonate according to claim 6 or 7, characterized in that, The average particle size of nano-calcium carbonate is no greater than 100 nm.

9. The method for modifying nano-calcium carbonate according to claim 6, characterized in that, In step 2), the mixing temperature is 60-85℃, the speed is 800-1500rpm, and the time is 15-40min.

10. The method for modifying nano-calcium carbonate according to claim 6, characterized in that, The static curing temperature is 40-60℃, and the static curing time is 1-3 hours.

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