Preparation method of high-dispersibility porous nano calcium carbonate filler

Abstract

The application discloses a preparation method of high-dispersibility porous nano calcium carbonate filler, which comprises the following steps: (1) preparing a buffer solution; adding chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide into the buffer solution under stirring, and stirring until uniform; adding 3,4-dihydroxybenzoic acid ethanol solution and sulfosuccinic acid, stirring and reacting, adjusting pH to neutral, and obtaining an additional solution; (2) mixing palmitic acid and N,N-dimethyl-1,2-ethylenediamine in a reaction kettle, adding water, stirring sufficiently, performing solid-liquid separation, adding 3-chloro-2-hydroxypropanesulfonic acid sodium into the liquid phase, heating and reacting, rotary evaporation, adding acetone, filtering, rotary evaporation, and drying to obtain an additive; (3) preparing a calcium chloride solution, adding the additional solution and the additive into the calcium chloride solution, adding sodium carbonate solution, stirring, aging, performing solid-liquid separation, washing, and drying to obtain the calcium carbonate filler. The calcium carbonate filler prepared by the method has a large specific surface area.

Description

Technical Field

[0001] This invention relates to the field of functional filler technology, and in particular to a method for preparing a highly dispersible porous nano-calcium carbonate filler. Background Technology

[0002] Calcium carbonate (CaCO3) is widely used in coatings, paints, and rubber industries due to its abundant availability and non-toxic, odorless properties. As a filler in coating preparation, calcium carbonate can increase surface roughness and improve hydrophobicity. However, fine nano-sized calcium carbonate particles are prone to agglomeration. When added to the matrix material, this often leads to a decrease in mechanical properties such as impact strength and tensile strength, as well as poor processing performance, significantly limiting its applications. Summary of the Invention

[0003] Therefore, the present invention provides a method for preparing highly dispersible porous nano-calcium carbonate filler, the steps of which include:

[0004] (1) Disodium hydrogen phosphate dodecahydrate was added to deionized water and the pH was adjusted to prepare a buffer solution; an ethanol solution of 3,4-dihydroxybenzoic acid was prepared; chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added to the buffer solution under stirring, and the mixture was stirred evenly after the addition was completed; then the ethanol solution of 3,4-dihydroxybenzoic acid and sulfosuccinic acid were added, and the mixture was stirred to react after the addition was completed, and then the pH was adjusted to neutral to obtain an additional solution;

[0005] (2) Palmitic acid and N,N-dimethyl-1,2-ethylenediamine are mixed in a reaction vessel, the reaction vessel is sealed, inert gas is introduced to purge the air, and then the mixture is heated to 150-180°C and kept at that temperature for reaction. After the reaction, the reaction vessel is opened, deionized water is added, and the mixture is stirred thoroughly. The liquid phase is then collected by solid-liquid separation. Sodium 3-chloro-2-hydroxypropanesulfonate is added to the liquid phase, and the mixture is heated to react. During the heating reaction, the mixture is refluxed. The deionized water in the product is removed by rotary evaporation, and then acetone is added to dissolve the product completely. The unreacted sodium 3-chloro-2-hydroxypropanesulfonate is removed by filtration, and the acetone is removed by rotary evaporation. The product is then dried to obtain the additive.

[0006] (3) Prepare an aqueous solution of calcium chloride, add the additional solution and the additive to the aqueous solution of calcium chloride under stirring, stir evenly after the addition is completed, heat and keep warm in a water bath, then add sodium carbonate solution, keep warm and stir after the addition, age at room temperature, separate solid and liquid, wash the solid phase, dry, and obtain the highly dispersible porous nano calcium carbonate filler.

[0007] Further, in step (1), the concentration of disodium hydrogen phosphate in the buffer solution is 0.05 mol / L and the pH is 5.5; in the ethanol solution of 3,4-dihydroxybenzoic acid, the concentration of 3,4-dihydroxybenzoic acid is 20-28 g / 100 mL and the solvent is ethanol.

[0008] Further, in step (1), the ratio of chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, ethanol solution of 3,4-dihydroxybenzoic acid, and sulfosuccinic acid added to the buffer solution is as follows: buffer solution: chitosan oligosaccharide: 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride: N-hydroxysuccinimide: ethanol solution of 3,4-dihydroxybenzoic acid: sulfosuccinic acid = 100mL: 5~6g: 2.2~2.6g: 1.5~2g: 10~20mL: 3~5g.

[0009] Furthermore, in step (1), after the addition of materials is completed, the mixture is stirred and reacted for 10 to 15 hours.

[0010] Further, in step (2), the ratio of palmitic acid, N,N-dimethyl-1,2-ethylenediamine, deionized water, and sodium 3-chloro-2-hydroxypropanesulfonate is palmitic acid: N,N-dimethyl-1,2-ethylenediamine: deionized water: sodium 3-chloro-2-hydroxypropanesulfonate = 12-16g: 7-10g: 50-60mL: 6-8g.

[0011] Furthermore, in step (2), the heating reaction temperature is 80±5℃ and the reaction time is 10~15h.

[0012] Furthermore, in step (2), the inert gas is nitrogen or argon.

[0013] Further, in step (3), the concentration of calcium chloride in the aqueous solution of calcium chloride is 40-60 g / L, and the solvent is water; the ratio of the additional solution, the additive, and the sodium carbonate solution added to the aqueous solution of calcium chloride is: aqueous solution of calcium chloride: additional solution: additive: sodium carbonate solution = 10 mL: 3-6 mL: 0.3-0.5 g: 12-20 mL, wherein the concentration of sodium carbonate in the sodium carbonate solution is 50-55 g / L, and the solvent is water.

[0014] Furthermore, in step (3), after adding the material, the mixture is kept at 50±10℃ and stirred for more than 60 minutes, and the aging time is more than 3 hours.

[0015] The beneficial effects of this invention are as follows: the porous calcium carbonate filler prepared by the method described in this invention has a large specific surface area. Adding the filler to the resin matrix can significantly increase the bonding surface between the filler and the matrix, improve the bonding force between the filler and the matrix, and improve the overall performance of the composite material. This invention, by introducing the aforementioned additional solution and additives during the synthesis of calcium carbonate, can significantly increase the specific surface area of ​​the final filler particles, indicating that the pore distribution and density on the filler surface are improved. This may be because: firstly, by attaching 3,4-dihydroxybenzoic acid and sulfosuccinic acid to the amino group of the chitosan oligosaccharide molecule, phenolic hydroxyl groups are introduced into the chitosan oligosaccharide molecule. Utilizing the negative charge of the phenolic hydroxyl groups, they coordinate with calcium ions through charge matching, thereby controlling the particle size, morphology, and crystal form of calcium carbonate particles during the reaction to form calcium carbonate, thus increasing the specific surface area of ​​the particles. Secondly, by introducing sulfonic acid groups, the strong complexation between the sulfonic acid groups and calcium ions plays an important role in inducing calcium carbonate crystal nucleation and inhibiting crystal growth. Subsequently, by synthesizing additives, which are added as activators to the reaction process, the aggregation of calcium carbonate crystals can be prevented, the grain size of the filler particles can be reduced, and the dispersibility of the particles can be improved. Attached Figure Description

[0016] Figure 1 A comparison chart showing the specific surface area of ​​calcium carbonate prepared by the methods described in each embodiment and comparative example. Detailed Implementation

[0017] The present invention will be further described below with reference to the embodiments.

[0018] Example 1

[0019] A method for preparing highly dispersible porous nano-calcium carbonate filler, comprising the following steps:

[0020] (1) Disodium hydrogen phosphate dodecahydrate was dissolved in deionized water and the pH was adjusted to 5.5 with 1 mol / L sodium hydroxide aqueous solution to prepare a buffer solution. The concentration of disodium hydrogen phosphate in the buffer solution was 0.05 mol / L. An ethanol solution of 3,4-dihydroxybenzoic acid was prepared. The concentration of 3,4-dihydroxybenzoic acid in the ethanol solution was 20 g / 100 mL, and the solvent was ethanol. Chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added to the buffer solution under stirring. After the addition was completed, the mixture was stirred for 10 min to mix evenly. Then the 3,4-dihydroxybenzoic acid was added. An ethanol solution of 3,4-dihydroxybenzoic acid and sulfosuccinic acid were prepared. Chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, and sulfosuccinic acid were added to the buffer solution. The ratio of the ethanol solution of 3,4-dihydroxybenzoic acid to sulfosuccinic acid was 100 mL: 5 g: 2.2 g: 1.5 g: 10 mL: 3 g. After the addition was complete, the mixture was stirred at room temperature for 10 h. Then, the pH was adjusted to neutral with a 1 mol / L sodium hydroxide aqueous solution or a 1 mol / L hydrochloric acid solution to obtain the additional solution.

[0021] (2) Palmitic acid and N,N-dimethyl-1,2-ethylenediamine were mixed in a reaction vessel, the reaction vessel was sealed, and nitrogen gas was introduced to purge the air, so that the reaction vessel was under nitrogen protection. Then the mixture was heated to 150°C and kept at that temperature for 5 hours. After the reaction, the reaction vessel was opened, deionized water was added, and the mixture was stirred for 20 minutes to ensure thorough mixing. The liquid phase was then collected by solid-liquid separation. Sodium 3-chloro-2-hydroxypropanesulfonate was added to the liquid phase. The palmitic acid, N,N-dimethyl-1,2-ethylenediamine, deionized water, and 3-chloro-2-hydroxypropanesulfonate used were... The molar ratio of sodium propanesulfonate was palmitic acid: N,N-dimethyl-1,2-ethylenediamine: deionized water: sodium 3-chloro-2-hydroxypropanesulfonate = 12g: 7g: 50mL: 6g; the mixture was then heated to 80℃ and kept at that temperature for 10h, with reflux during the heating process; the deionized water was removed by rotary evaporation of the product, and then acetone (30 times its mass) was added to the rotary evaporated product. The mixture was stirred for 30min to dissolve completely, filtered to remove unreacted sodium 3-chloro-2-hydroxypropanesulfonate, and the acetone was removed by rotary evaporation. The mixture was then dried at 60℃ for 10h to obtain the additive.

[0022] (3) Prepare an aqueous solution of calcium chloride, wherein the concentration of calcium chloride in the aqueous solution of calcium chloride is 40 g / L and the solvent is water; add the additional solution and the additive to the aqueous solution of calcium chloride under stirring, stir for 10 min after the addition is completed and mix evenly, heat to 50°C in a water bath and keep warm, and then add sodium carbonate solution. The ratio of the amount of the additional solution, the additive and the sodium carbonate solution added to the aqueous solution of calcium chloride is aqueous solution of calcium chloride: additional solution: additive: sodium carbonate solution = 10 mL: 3 mL: 0.3 g: 12 mL, wherein the concentration of sodium carbonate in the sodium carbonate solution is 50 g / L and the solvent is water; after the addition, keep warm at 50°C and stir for 60 min, age at room temperature for 3 h, separate solid and liquid, wash the solid phase with ethanol and deionized water three times in sequence, and dry at 80°C for 2 h to obtain the highly dispersible porous nano calcium carbonate filler.

[0023] Example 2

[0024] A method for preparing highly dispersible porous nano-calcium carbonate filler, comprising the following steps:

[0025] (1) Disodium hydrogen phosphate dodecahydrate was dissolved in deionized water and the pH was adjusted to 5.5 with 1 mol / L sodium hydroxide aqueous solution to prepare a buffer solution. The concentration of disodium hydrogen phosphate in the buffer solution was 0.05 mol / L. An ethanol solution of 3,4-dihydroxybenzoic acid was prepared. The concentration of 3,4-dihydroxybenzoic acid in the ethanol solution was 24 g / 100 mL, and the solvent was ethanol. Chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added to the buffer solution under stirring. After the addition was completed, the mixture was stirred for 10 min to mix evenly. Then the 3,4-dihydroxybenzoic acid was added. An ethanol solution of 3,4-dihydroxybenzoic acid and sulfosuccinic acid were prepared, and chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, and sulfosuccinic acid were added to the buffer solution. The ratio of the ethanol solution of 3,4-dihydroxybenzoic acid to sulfosuccinic acid was 100 mL: 5 g: 2.4 g: 1.5 g: 15 mL: 4 g. After the addition was completed, the mixture was stirred at room temperature for 10 h. Then, the pH was adjusted to neutral with 1 mol / L sodium hydroxide aqueous solution or 1 mol / L hydrochloric acid solution to obtain the additional solution.

[0026] (2) Palmitic acid and N,N-dimethyl-1,2-ethylenediamine were mixed in a reaction vessel, the reaction vessel was sealed, and nitrogen gas was introduced to purge the air, so that the reaction vessel was under nitrogen protection. Then the mixture was heated to 160°C and kept at that temperature for 5 hours. After the reaction, the reaction vessel was opened, deionized water was added, and the mixture was stirred for 20 minutes to ensure thorough mixing. The liquid phase was then collected by solid-liquid separation. Sodium 3-chloro-2-hydroxypropanesulfonate was added to the liquid phase. The palmitic acid, N,N-dimethyl-1,2-ethylenediamine, deionized water, and 3-chloro-2-hydroxypropanesulfonate used were... The molar ratio of sodium propanesulfonate was palmitic acid: N,N-dimethyl-1,2-ethylenediamine: deionized water: sodium 3-chloro-2-hydroxypropanesulfonate = 14g: 9g: 55mL: 7g; the mixture was then heated to 80℃ and kept at that temperature for 10h, with reflux during the heating process; the deionized water was removed by rotary evaporation of the product, and then acetone (30 times its mass) was added to the rotary evaporated product. The mixture was stirred for 30min to dissolve completely, filtered to remove unreacted sodium 3-chloro-2-hydroxypropanesulfonate, and the acetone was removed by rotary evaporation. The mixture was then dried at 60℃ for 10h to obtain the additive.

[0027] (3) Prepare an aqueous solution of calcium chloride, wherein the concentration of calcium chloride in the aqueous solution of calcium chloride is 50 g / L and the solvent is water; add the additional solution and the additive to the aqueous solution of calcium chloride under stirring, stir for 10 min after the addition is completed and mix evenly, heat to 50°C in a water bath and keep warm, and then add sodium carbonate solution. The ratio of the amount of the additional solution, the additive and the sodium carbonate solution added to the aqueous solution of calcium chloride is aqueous solution of calcium chloride: additional solution: additive: sodium carbonate solution = 10 mL: 4 mL: 0.4 g: 16 mL, wherein the concentration of sodium carbonate in the sodium carbonate solution is 50 g / L and the solvent is water; after the addition, keep warm at 50°C and stir for 60 min, age at room temperature for 3 h, separate the solid and liquid, wash the solid phase with ethanol and deionized water three times in sequence, and dry at 80°C for 2 h to obtain the highly dispersible porous nano calcium carbonate filler.

[0028] Example 3

[0029] A method for preparing highly dispersible porous nano-calcium carbonate filler, comprising the following steps:

[0030] (1) Disodium hydrogen phosphate dodecahydrate was dissolved in deionized water and the pH was adjusted to 5.5 with 1 mol / L sodium hydroxide aqueous solution to prepare a buffer solution. The concentration of disodium hydrogen phosphate in the buffer solution was 0.05 mol / L. An ethanol solution of 3,4-dihydroxybenzoic acid was prepared. The concentration of 3,4-dihydroxybenzoic acid in the ethanol solution was 26 g / 100 mL, and the solvent was ethanol. Chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added to the buffer solution under stirring. After the addition was completed, the mixture was stirred for 10 min to mix evenly. Then the 3,4-dihydroxybenzoic acid was added. An ethanol solution of formic acid and sulfosuccinic acid were prepared, and chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, ethanol solution of 3,4-dihydroxybenzoic acid, and sulfosuccinic acid were added to a buffer solution. The ratio of buffer solution: chitosan oligosaccharide: 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride: N-hydroxysuccinimide: ethanol solution of 3,4-dihydroxybenzoic acid: sulfosuccinic acid = 100mL: 6g: 2.4g: 2g: 15mL: 4g. After the addition was completed, the mixture was stirred at room temperature for 10 hours. Then, the pH was adjusted to neutral with 1mol / L sodium hydroxide aqueous solution or 1mol / L hydrochloric acid solution to obtain an additional solution.

[0031] (2) Palmitic acid and N,N-dimethyl-1,2-ethylenediamine were mixed in a reaction vessel, the reaction vessel was sealed, and nitrogen gas was introduced to purge the air, so that the reaction vessel was under nitrogen protection. Then the mixture was heated to 170°C and kept at that temperature for 4 hours. After the reaction, the reaction vessel was opened, deionized water was added, and the mixture was stirred for 20 minutes to ensure thorough mixing. The liquid phase was then collected by solid-liquid separation. Sodium 3-chloro-2-hydroxypropanesulfonate was added to the liquid phase. The palmitic acid, N,N-dimethyl-1,2-ethylenediamine, deionized water, and 3-chloro-2-hydroxypropanesulfonate used were... The molar ratio of sodium propanesulfonate was palmitic acid: N,N-dimethyl-1,2-ethylenediamine: deionized water: sodium 3-chloro-2-hydroxypropanesulfonate = 14g: 9g: 55mL: 7g; the mixture was then heated to 80℃ and kept at that temperature for 10h, with reflux during the heating process; the deionized water was removed by rotary evaporation of the product, and then acetone (30 times its mass) was added to the rotary evaporated product. The mixture was stirred for 30min to dissolve completely, filtered to remove unreacted sodium 3-chloro-2-hydroxypropanesulfonate, and the acetone was removed by rotary evaporation. The mixture was then dried at 60℃ for 10h to obtain the additive.

[0032] (3) Prepare an aqueous solution of calcium chloride, wherein the concentration of calcium chloride in the aqueous solution of calcium chloride is 50 g / L and the solvent is water; add the additional solution and the additive to the aqueous solution of calcium chloride under stirring, stir for 10 min after the addition is completed and mix evenly, heat to 50°C in a water bath and keep warm, and then add sodium carbonate solution. The ratio of the amount of the additional solution, the additive and the sodium carbonate solution added to the aqueous solution of calcium chloride is aqueous solution of calcium chloride: additional solution: additive: sodium carbonate solution = 10 mL: 5 mL: 0.4 g: 18 mL, wherein the concentration of sodium carbonate in the sodium carbonate solution is 55 g / L and the solvent is water; after the addition, keep warm at 50°C and stir for 60 min, age at room temperature for 3 h, separate solid and liquid, wash the solid phase with ethanol and deionized water three times in sequence, and dry at 80°C for 2 h to obtain the highly dispersible porous nano calcium carbonate filler.

[0033] Example 4

[0034] A method for preparing highly dispersible porous nano-calcium carbonate filler, comprising the following steps:

[0035] (1) Disodium hydrogen phosphate dodecahydrate was dissolved in deionized water and the pH was adjusted to 5.5 with 1 mol / L sodium hydroxide aqueous solution to prepare a buffer solution. The concentration of disodium hydrogen phosphate in the buffer solution was 0.05 mol / L. An ethanol solution of 3,4-dihydroxybenzoic acid was prepared. The concentration of 3,4-dihydroxybenzoic acid in the ethanol solution was 28 g / 100 mL, and the solvent was ethanol. Chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added to the buffer solution under stirring. After the addition was completed, the mixture was stirred for 10 min to mix evenly. Then the 3,4-dihydroxybenzoic acid was added. An ethanol solution of formic acid and sulfosuccinic acid were prepared, and chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, and ethanol solution of 3,4-dihydroxybenzoic acid and sulfosuccinic acid were added to a buffer solution. The ratio of buffer solution: chitosan oligosaccharide: 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride: N-hydroxysuccinimide: ethanol solution of 3,4-dihydroxybenzoic acid: sulfosuccinic acid = 100mL: 6g: 2.6g: 2g: 20mL: 5g. After the addition was completed, the mixture was stirred at room temperature for 10 hours. Then, the pH was adjusted to neutral with 1mol / L sodium hydroxide aqueous solution or 1mol / L hydrochloric acid solution to obtain an additional solution.

[0036] (2) Palmitic acid and N,N-dimethyl-1,2-ethylenediamine were mixed in a reaction vessel, the reaction vessel was sealed, and nitrogen gas was introduced to purge the air, so that the reaction vessel was under nitrogen protection. Then the mixture was heated to 180°C and kept at that temperature for 4 hours. After the reaction, the reaction vessel was opened, deionized water was added, and the mixture was stirred for 20 minutes to ensure thorough mixing. The liquid phase was then collected by solid-liquid separation. Sodium 3-chloro-2-hydroxypropanesulfonate was added to the liquid phase. The palmitic acid, N,N-dimethyl-1,2-ethylenediamine, deionized water, and 3-chloro-2-hydroxypropanesulfonate used were... The molar ratio of sodium propanesulfonate was palmitic acid: N,N-dimethyl-1,2-ethylenediamine: deionized water: sodium 3-chloro-2-hydroxypropanesulfonate = 16g: 10g: 60mL: 8g; the mixture was then heated to 80℃ and kept at that temperature for 10h, with reflux during the heating process; the deionized water was removed by rotary evaporation of the product, and then acetone (30 times its mass) was added to the rotary evaporated product. The mixture was stirred for 30min to dissolve completely, filtered to remove unreacted sodium 3-chloro-2-hydroxypropanesulfonate, and the acetone was removed by rotary evaporation. The mixture was then dried at 60℃ for 10h to obtain the additive.

[0037] (3) Prepare an aqueous solution of calcium chloride, wherein the concentration of calcium chloride in the aqueous solution of calcium chloride is 60 g / L and the solvent is water; add the additional solution and the additive to the aqueous solution of calcium chloride under stirring, stir for 10 min after the addition is completed and mix evenly, heat to 50°C in a water bath and keep warm, and then add sodium carbonate solution. The ratio of the amount of the additional solution, the additive and the sodium carbonate solution added to the aqueous solution of calcium chloride is aqueous solution of calcium chloride: additional solution: additive: sodium carbonate solution = 10 mL: 6 mL: 0.5 g: 20 mL, wherein the concentration of sodium carbonate in the sodium carbonate solution is 55 g / L and the solvent is water; after the addition, keep warm at 50°C and stir for 60 min, age at room temperature for 3 h, separate the solid and liquid, wash the solid phase with ethanol and deionized water three times in sequence, and dry at 80°C for 2 h to obtain the highly dispersible porous nano calcium carbonate filler.

[0038] Comparative Example 1

[0039] A comparative method for preparing calcium carbonate includes the following steps:

[0040] (1) Disodium hydrogen phosphate dodecahydrate was dissolved in deionized water and the pH was adjusted to 5.5 with 1 mol / L sodium hydroxide aqueous solution to prepare a buffer solution. The concentration of disodium hydrogen phosphate in the buffer solution was 0.05 mol / L. Chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and N-hydroxysuccinimide were added to the buffer solution under stirring. After the addition was complete, the mixture was stirred for 10 min to mix thoroughly. Then, sulfosuccinic acid was added, and chitosan oligosaccharide was added to the buffer solution. The ratio of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, and sulfosuccinic acid was buffer: chitosan oligosaccharide: 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride: N-hydroxysuccinimide: sulfosuccinic acid = 100 mL: 6 g: 2.4 g: 2 g: 4 g. After the addition was completed, the mixture was stirred at room temperature for 10 h, and then the pH was adjusted to neutral with 1 mol / L sodium hydroxide aqueous solution or 1 mol / L hydrochloric acid solution to obtain the additional solution.

[0041] (2) Palmitic acid and N,N-dimethyl-1,2-ethylenediamine were mixed in a reaction vessel, the reaction vessel was sealed, and nitrogen gas was introduced to purge the air, so that the reaction vessel was under nitrogen protection. Then the mixture was heated to 170°C and kept at that temperature for 4 hours. After the reaction, the reaction vessel was opened, deionized water was added, and the mixture was stirred for 20 minutes to ensure thorough mixing. The liquid phase was then collected by solid-liquid separation. Sodium 3-chloro-2-hydroxypropanesulfonate was added to the liquid phase. The palmitic acid, N,N-dimethyl-1,2-ethylenediamine, deionized water, and 3-chloro-2-hydroxypropanesulfonate used were... The molar ratio of sodium propanesulfonate was palmitic acid: N,N-dimethyl-1,2-ethylenediamine: deionized water: sodium 3-chloro-2-hydroxypropanesulfonate = 14g: 9g: 55mL: 7g; the mixture was then heated to 80℃ and kept at that temperature for 10h, with reflux during the heating process; the deionized water was removed by rotary evaporation of the product, and then acetone (30 times its mass) was added to the rotary evaporated product. The mixture was stirred for 30min to dissolve completely, filtered to remove unreacted sodium 3-chloro-2-hydroxypropanesulfonate, and the acetone was removed by rotary evaporation. The mixture was then dried at 60℃ for 10h to obtain the additive.

[0042] (3) Prepare an aqueous solution of calcium chloride, wherein the concentration of calcium chloride in the aqueous solution of calcium chloride is 50 g / L and the solvent is water; add the additional solution and the additive to the aqueous solution of calcium chloride under stirring, stir for 10 min after the addition is completed and mix evenly, heat to 50°C in a water bath and keep warm, and then add sodium carbonate solution. The ratio of the amount of the additional solution, the additive and the sodium carbonate solution added to the aqueous solution of calcium chloride is aqueous solution of calcium chloride: additional solution: additive: sodium carbonate solution = 10 mL: 5 mL: 0.4 g: 18 mL, wherein the concentration of sodium carbonate in the sodium carbonate solution is 55 g / L and the solvent is water; after the addition, keep warm at 50°C and stir for 60 min, age at room temperature for 3 h, separate the solid and liquid, wash the solid phase with ethanol and deionized water three times in sequence, and dry at 80°C for 2 h to obtain the calcium carbonate of this comparative example.

[0043] Comparative Example 2

[0044] A comparative method for preparing calcium carbonate includes the following steps:

[0045] (1) Disodium hydrogen phosphate dodecahydrate was dissolved in deionized water and the pH was adjusted to 5.5 with 1 mol / L sodium hydroxide aqueous solution to prepare a buffer solution. The concentration of disodium hydrogen phosphate in the buffer solution was 0.05 mol / L. An ethanol solution of 3,4-dihydroxybenzoic acid was prepared. The concentration of 3,4-dihydroxybenzoic acid in the ethanol solution was 26 g / 100 mL, and the solvent was ethanol. Chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added to the buffer solution under stirring. After the addition was completed, the mixture was stirred for 10 min to mix evenly. Then, the following was added: The ethanol solution of 3,4-dihydroxybenzoic acid was prepared by adding chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, and ethanol solution of 3,4-dihydroxybenzoic acid in a buffer solution with the following ratio: buffer solution: chitosan oligosaccharide: 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride: N-hydroxysuccinimide: ethanol solution of 3,4-dihydroxybenzoic acid = 100 mL: 6 g: 2.4 g: 2 g: 15 mL. After the addition was completed, the mixture was stirred at room temperature for 10 h, and then the pH was adjusted to neutral with 1 mol / L sodium hydroxide aqueous solution or 1 mol / L hydrochloric acid solution to obtain an additional solution.

[0046] (2) Palmitic acid and N,N-dimethyl-1,2-ethylenediamine were mixed in a reaction vessel, the reaction vessel was sealed, and nitrogen gas was introduced to purge the air, so that the reaction vessel was under nitrogen protection. Then the mixture was heated to 170°C and kept at that temperature for 4 hours. After the reaction, the reaction vessel was opened, deionized water was added, and the mixture was stirred for 20 minutes to ensure thorough mixing. The liquid phase was then collected by solid-liquid separation. Sodium 3-chloro-2-hydroxypropanesulfonate was added to the liquid phase. The palmitic acid, N,N-dimethyl-1,2-ethylenediamine, deionized water, and 3-chloro-2-hydroxypropanesulfonate used were... The molar ratio of sodium propanesulfonate was palmitic acid: N,N-dimethyl-1,2-ethylenediamine: deionized water: sodium 3-chloro-2-hydroxypropanesulfonate = 14g: 9g: 55mL: 7g; the mixture was then heated to 80℃ and kept at that temperature for 10h, with reflux during the heating process; the deionized water was removed by rotary evaporation of the product, and then acetone (30 times its mass) was added to the rotary evaporated product. The mixture was stirred for 30min to dissolve completely, filtered to remove unreacted sodium 3-chloro-2-hydroxypropanesulfonate, and the acetone was removed by rotary evaporation. The mixture was then dried at 60℃ for 10h to obtain the additive.

[0047] (3) Prepare an aqueous solution of calcium chloride, wherein the concentration of calcium chloride in the aqueous solution of calcium chloride is 50 g / L and the solvent is water; add the additional solution and the additive to the aqueous solution of calcium chloride under stirring, stir for 10 min after the addition is completed and mix evenly, heat to 50°C in a water bath and keep warm, and then add sodium carbonate solution. The ratio of the amount of the additional solution, the additive and the sodium carbonate solution added to the aqueous solution of calcium chloride is aqueous solution of calcium chloride: additional solution: additive: sodium carbonate solution = 10 mL: 5 mL: 0.4 g: 18 mL, wherein the concentration of sodium carbonate in the sodium carbonate solution is 55 g / L and the solvent is water; after the addition, keep warm at 50°C and stir for 60 min, age at room temperature for 3 h, separate the solid and liquid, wash the solid phase with ethanol and deionized water three times in sequence, and dry at 80°C for 2 h to obtain the calcium carbonate of this comparative example.

[0048] Comparative Example 3

[0049] A comparative method for preparing calcium carbonate includes the following steps:

[0050] (1) Disodium hydrogen phosphate dodecahydrate was dissolved in deionized water and the pH was adjusted to 5.5 with 1 mol / L sodium hydroxide aqueous solution to prepare a buffer solution. The concentration of disodium hydrogen phosphate in the buffer solution was 0.05 mol / L. An ethanol solution of 3,4-dihydroxybenzoic acid was prepared. The concentration of 3,4-dihydroxybenzoic acid in the ethanol solution was 26 g / 100 mL, and the solvent was ethanol. Chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added to the buffer solution under stirring. After the addition was completed, the mixture was stirred for 10 min to mix evenly. Then the 3,4-dihydroxybenzoic acid was added. An ethanol solution of formic acid and sulfosuccinic acid were prepared, and chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, ethanol solution of 3,4-dihydroxybenzoic acid, and sulfosuccinic acid were added to a buffer solution. The ratio of buffer solution: chitosan oligosaccharide: 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride: N-hydroxysuccinimide: ethanol solution of 3,4-dihydroxybenzoic acid: sulfosuccinic acid = 100mL: 6g: 2.4g: 2g: 15mL: 4g. After the addition was completed, the mixture was stirred at room temperature for 10 hours. Then, the pH was adjusted to neutral with 1mol / L sodium hydroxide aqueous solution or 1mol / L hydrochloric acid solution to obtain an additional solution.

[0051] (2) Prepare an aqueous solution of calcium chloride, wherein the concentration of calcium chloride in the aqueous solution of calcium chloride is 50 g / L and the solvent is water; add the additional solution to the aqueous solution of calcium chloride under stirring, stir for 10 min after the addition is completed and mix evenly, heat to 50°C in a water bath and keep warm, and then add sodium carbonate solution. The ratio of the amount of the additional solution to the amount of sodium carbonate solution added to the aqueous solution of calcium chloride is aqueous solution of calcium chloride: additional solution: sodium carbonate solution = 10 mL: 5 mL: 18 mL, wherein the concentration of sodium carbonate in the sodium carbonate solution is 55 g / L and the solvent is water; after the addition, keep warm at 50°C and stir for 60 min, age at room temperature for 3 h, separate the solid and liquid, wash the solid phase with ethanol and deionized water three times in sequence, and dry at 80°C for 2 h to obtain the calcium carbonate described in this comparative example.

[0052] Example 5

[0053] The specific surface area of ​​the calcium carbonate prepared by the methods described in the above embodiments and comparative examples was tested, and the results are as follows: Figure 1 As shown.

[0054] Depend on Figure 1It is known that the porous calcium carbonate filler prepared by the method described in this invention has a large specific surface area. Adding the filler to the resin matrix can significantly increase the bonding surface between the filler and the matrix, improve the bonding force between the filler and the matrix, and improve the overall performance of the composite material. This invention, by introducing the aforementioned additional solution and additives during the synthesis of calcium carbonate, can significantly increase the specific surface area of ​​the final filler particles, indicating that the pore distribution and density on the filler surface are improved. This may be because: firstly, by attaching 3,4-dihydroxybenzoic acid and sulfosuccinic acid to the amino groups of the chitosan oligosaccharide molecules, phenolic hydroxyl groups are introduced into the chitosan oligosaccharide molecules. Utilizing the negative charge of the phenolic hydroxyl groups, they coordinate with calcium ions through charge matching, thereby controlling the particle size, morphology, and crystal form of calcium carbonate particles during the reaction to form calcium carbonate, thus increasing the specific surface area of ​​the particles. Secondly, by introducing sulfonic acid groups, the strong complexation between the sulfonic acid groups and calcium ions plays an important role in inducing calcium carbonate crystal nucleation and inhibiting crystal growth. Subsequently, by synthesizing additives, which are added as activators to the reaction process, the aggregation of calcium carbonate crystals can be prevented, the grain size of the filler particles can be reduced, and the dispersibility of the particles can be improved.

[0055] The technical solutions provided by the present invention have been described in detail above. For those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing highly dispersible porous nano-calcium carbonate filler, characterized in that the steps include... include: (1) Add disodium hydrogen phosphate dodecahydrate to deionized water and adjust the pH to prepare a buffer solution; Prepare an ethanol solution of 3,4-dihydroxybenzoic acid; add chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide to the buffer solution while stirring, and stir until homogeneous after addition; then add the ethanol solution of 3,4-dihydroxybenzoic acid and sulfosuccinic acid, stir the reaction after addition, and then adjust the pH to neutral to obtain the additional solution; (2) Palmitic acid and N,N-dimethyl-1,2-ethylenediamine are mixed in a reaction vessel, the reaction vessel is sealed, inert gas is introduced to purge the air, and then the mixture is heated to 150-180°C and kept at that temperature for reaction. After the reaction, the reaction vessel is opened, deionized water is added, and the mixture is stirred thoroughly. The liquid phase is then collected by solid-liquid separation. Sodium 3-chloro-2-hydroxypropanesulfonate is added to the liquid phase, and the mixture is heated to react. During the heating reaction, the mixture is refluxed. The deionized water in the product is removed by rotary evaporation, and then acetone is added to dissolve the product completely. The unreacted sodium 3-chloro-2-hydroxypropanesulfonate is removed by filtration, and the acetone is removed by rotary evaporation. The product is then dried to obtain the additive. (3) Prepare an aqueous solution of calcium chloride, add the additional solution and the additive to the aqueous solution of calcium chloride under stirring, stir evenly after the addition is completed, heat and keep warm in a water bath, then add sodium carbonate solution, keep warm and stir after the addition, age at room temperature, separate solid and liquid, wash the solid phase, dry, and obtain the highly dispersible porous nano calcium carbonate filler.

2. The method for preparing a highly dispersible porous nano-calcium carbonate filler according to claim 1, characterized in that, In step (1), the concentration of disodium hydrogen phosphate in the buffer solution is 0.05 mol / L and the pH is 5.5; in the ethanol solution of 3,4-dihydroxybenzoic acid, the concentration of 3,4-dihydroxybenzoic acid is 20-28 g / 100 mL and the solvent is ethanol.

3. The method for preparing a highly dispersible porous nano-calcium carbonate filler according to claim 1, characterized in that, In step (1), the buffer solution contains chitosan oligosaccharide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, an ethanol solution of 3,4-dihydroxybenzoic acid, and sulfosuccinic acid in the following ratio: buffer solution: chitosan oligosaccharide: 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride: N-hydroxysuccinimide: ethanol solution of 3,4-dihydroxybenzoic acid: sulfosuccinic acid = 100mL: 5~6g: 2.2~2.6g: 1.5~2g: 10~20mL: 3~5g.

4. The method for preparing a highly dispersible porous nano-calcium carbonate filler according to claim 1, characterized in that, In step (1), after the material is added, the mixture is stirred and reacted for 10 to 15 hours.

5. The method for preparing a highly dispersible porous nano-calcium carbonate filler according to claim 1, characterized in that, In step (2), the ratio of palmitic acid, N,N-dimethyl-1,2-ethylenediamine, deionized water, and sodium 3-chloro-2-hydroxypropanesulfonate is palmitic acid: N,N-dimethyl-1,2-ethylenediamine: deionized water: sodium 3-chloro-2-hydroxypropanesulfonate = 12-16g: 7-10g: 50-60mL: 6-8g.

6. The method for preparing a highly dispersible porous nano-calcium carbonate filler according to claim 1, characterized in that, In step (2), the heating reaction temperature is 80±5℃ and the reaction time is 10~15h.

7. The method for preparing a highly dispersible porous nano-calcium carbonate filler according to claim 1, characterized in that, In step (2), the inert gas is nitrogen or argon.

8. The method for preparing a highly dispersible porous nano-calcium carbonate filler according to claim 1, characterized in that, In step (3), the concentration of calcium chloride in the aqueous solution is 40-60 g / L, and the solvent is water; the ratio of the additional solution, the additive, and the sodium carbonate solution added to the aqueous solution of calcium chloride is: aqueous solution of calcium chloride: additional solution: additive: sodium carbonate solution = 10 mL: 3-6 mL: 0.3-0.5 g: 12-20 mL, wherein the concentration of sodium carbonate in the sodium carbonate solution is 50-55 g / L, and the solvent is water.

9. The method for preparing a highly dispersible porous nano-calcium carbonate filler according to claim 1, characterized in that, In step (3), after adding the material, the mixture is kept at 50±10℃ and stirred for more than 60 minutes, and the aging time is more than 3 hours.

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