Cyclic highly water-resistant calcium carbonate coupling agent, synthesis method and application thereof

Abstract

The invention discloses a cyclic high water-resistant calcium carbonate coupling agent, which is synthesized by the following method: taking boric acid and toluene, stirring, adding cycloheptanol dropwise, completing the addition for 1h, and then heating and refluxing for 6h; cooling to room temperature, adding diethanolamine dropwise, completing the addition for 1h, and then heating and refluxing for 12h, removing toluene and diethanolamine by vacuum distillation to obtain a cyclic high water-resistant calcium carbonate coupling agent. The present invention also discloses a synthesis method and application of a cyclic high water-resistant calcium carbonate coupling agent. The cyclic high water-resistant calcium carbonate coupling agent provided by the present invention introduces a hydrophobic cyclic large steric hindered group on the B-O bond, which can effectively suppress the attack of water molecules, slow down the hydrolysis rate, enhance the hydrolysis stability and practicality of the borate coupling agent, and significantly improve the quality and performance of calcium carbonate powder and downstream products.

Description

Technical Field

[0001] The invention relates to a calcium carbonate coupling agent, in particular to a cyclic highly water-resistant calcium carbonate coupling agent and a synthesis method and application thereof. Background Art

[0002] Calcium carbonate, as a high-quality filler, is widely used in industries such as rubber, plastics, papermaking, coatings, inks, and pharmaceuticals. However, due to the hydrophilic and oleophobic nature of inorganic powders, they are difficult to disperse evenly in organic media, resulting in a decrease in the mechanical properties of the material. Therefore, they must be surface modified or activated before filling. The central boron atom of borate coupling agents has a unique valence electron configuration, which further helps improve the mechanical properties of materials. They possess excellent properties not found in other traditional coupling agents or surface modifiers, and their synthesis and performance research have attracted widespread attention. However, traditional borate coupling agents have poor hydrolytic stability, resulting in poor dispersibility and flowability of the activated powder, which seriously affects the quality and performance of downstream products, thus limiting their application. Summary of the Invention

[0003] Borate coupling agents have poor hydrolytic stability, resulting in increased oil absorption and poor dispersibility and fluidity of the modified calcium carbonate, seriously affecting the quality and performance of downstream products. This invention introduces a hydrophobic cyclic, large steric group at the BO bond, effectively inhibiting water attack and slowing hydrolysis. This enhances the hydrolytic stability and practicality of the borate coupling agent, significantly improving the quality and performance of calcium carbonate powder and downstream products.

[0004] One of the objects of the present invention is to provide a cyclic highly water-resistant calcium carbonate coupling agent.

[0005] Specifically, a cyclic highly water-resistant calcium carbonate coupling agent is synthesized by the following method: boric acid and toluene are stirred, cycloheptanol is added dropwise over 1 hour, and then the temperature is raised to reflux for 6 hours; the mixture is cooled to room temperature, diethanolamine is added dropwise over 1 hour, and then the temperature is raised to reflux for 12 hours, and the toluene and diethanolamine are removed by reduced pressure distillation to obtain a cyclic highly water-resistant calcium carbonate coupling agent.

[0006] The molar ratio of boric acid to cycloheptanol is 1:1.

[0007] The molar ratio of boric acid to diethanolamine is 0.4:0.4-0.5.

[0008]

[0009] A second object of the present invention is to provide a method for synthesizing the above-mentioned cyclic highly water-resistant calcium carbonate coupling agent.

[0010] Specifically, the synthesis method of the cyclic highly water-resistant calcium carbonate coupling agent comprises the following steps: taking boric acid and toluene, stirring, adding cycloheptanol dropwise over 1 hour, and then heating and refluxing for 6 hours; cooling to room temperature, adding diethanolamine dropwise over 1 hour, and then heating and refluxing for 12 hours; and removing toluene and diethanolamine by reduced pressure distillation to obtain the cyclic highly water-resistant calcium carbonate coupling agent.

[0011] The molar ratio of boric acid to cycloheptanol is 1:1.

[0012] The molar ratio of boric acid to diethanolamine is 0.4:0.4-0.5. That is, the amount of diethanolamine in the present invention is preferably 0.40-0.50 mol.

[0013] A third object of the present invention is to provide an application of the cyclic highly water-resistant calcium carbonate coupling agent, particularly in the modification of calcium carbonate powder.

[0014] Specifically, the cyclic highly water-resistant calcium carbonate coupling agent is used in the modification of calcium carbonate powder. The calcium carbonate powder is placed in a modifying machine, heated and stirred, and the cyclic highly water-resistant calcium carbonate coupling agent is added dropwise to obtain highly activated calcium carbonate powder with excellent dispersibility and fluidity.

[0015] The amount of the dropwise added cyclic highly water-resistant calcium carbonate coupling agent is preferably 1.4 to 1.8% of the mass of the calcium carbonate powder.

[0016] The heating temperature is preferably 80-90°C.

[0017] The stirring time is preferably 15 to 20 minutes.

[0018] Technical effects of the present invention:

[0019] The cyclic, highly water-resistant calcium carbonate coupling agent provided by this invention incorporates a hydrophobic, cyclic, and bulky steric group on the B-O bond, effectively inhibiting water attack, slowing hydrolysis, and enhancing the hydrolytic stability of the borate coupling agent. The hydrolytic stability of the cyclic, highly water-resistant calcium carbonate coupling agent was 864 hours, compared to the 8-20 hours for conventional borate esters, demonstrating its superior hydrolytic stability.

[0020] 2. The cyclic highly water-resistant calcium carbonate coupling agent provided by the present invention can significantly reduce the oil absorption value of calcium carbonate powder, improve its dispersibility and fluidity, and significantly enhance the hydrolysis stability and practicality, thereby improving the quality and performance of calcium carbonate powder and downstream products, and has significant economic and promotional value.

[0021] The inventors have verified through experiments that the oil absorption value of heavy calcium carbonate powder is 36g / 100g. After modification with a cyclic highly water-resistant calcium carbonate coupling agent, the oil absorption value is reduced to 14-16g / 100g, and the powder has excellent dispersibility and fluidity. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to specific embodiments.

[0023] Example 1

[0024] (1) Boric acid 0.4 mol, toluene 200 mL, stirred, cycloheptanol 0.4 mol was slowly added dropwise over 1 hour, the temperature was raised and refluxed for 6 hours, and the solvent was removed by distillation under reduced pressure to obtain cycloheptanol borate.

[0025] (2) Add 200 mL of toluene, slowly dropwise add 0.42 mol of diethanolamine, complete the addition over 1 hour, heat and reflux for 12 hours, and remove toluene and diethanolamine by vacuum distillation to obtain a cyclic highly water-resistant calcium carbonate coupling agent with a yield of 85%.

[0026] (3) Calcium carbonate powder modified with a cyclic highly water-resistant calcium carbonate coupling agent (1250 mesh, oil absorption value of 36g / 100g) was added in an amount of 1.4% of the mass of the calcium carbonate powder. After heating to 80°C and stirring for 15 minutes, highly activated calcium carbonate powder with excellent dispersibility and fluidity was obtained, and its oil absorption value was 15g / 100g of calcium carbonate powder.

[0027] Example 2

[0028] (1) Boric acid 0.4 mol, toluene 200 mL, stirred, cycloheptanol 0.4 mol was slowly added dropwise over 1 hour, the temperature was raised and refluxed for 6 hours, and the solvent was removed by distillation under reduced pressure to obtain cycloheptanol borate.

[0029] (2) Add 200 mL of toluene, slowly dropwise add 0.45 mol of diethanolamine, complete the addition over 1 hour, heat and reflux for 12 hours, and remove toluene and diethanolamine by vacuum distillation to obtain a cyclic highly water-resistant calcium carbonate coupling agent with a yield of 86%.

[0030] (3) Calcium carbonate powder modified with a cyclic highly water-resistant calcium carbonate coupling agent (1250 mesh, oil absorption value of 36g / 100g) was added in an amount of 1.6% of the mass of the calcium carbonate powder. After heating to 80°C and stirring for 16 minutes, highly activated calcium carbonate powder with excellent dispersibility and fluidity was obtained, and the oil absorption value was 14g / 100g of calcium carbonate powder.

[0031] Example 3

[0032] (1) Boric acid 0.4 mol, toluene 200 mL, stirred, cycloheptanol 0.4 mol was slowly added dropwise over 1 hour, the temperature was raised and refluxed for 6 hours, and the solvent was removed by distillation under reduced pressure to obtain cycloheptanol borate.

[0033] (2) Add 200 mL of toluene, slowly dropwise add 0.50 mol of diethanolamine, complete the addition over 1 hour, heat and reflux for 12 hours, and remove toluene and diethanolamine by vacuum distillation to obtain a cyclic highly water-resistant calcium carbonate coupling agent with a yield of 88%.

[0034] (3) Calcium carbonate powder modified with a cyclic highly water-resistant calcium carbonate coupling agent (1250 mesh, oil absorption value of 36g / 100g) was added in an amount of 1.8% of the mass of the calcium carbonate powder. After heating at 90°C and stirring for 20 minutes, highly activated calcium carbonate powder with excellent dispersibility and fluidity was obtained, and the oil absorption value was 16g / 100g of calcium carbonate powder.

[0035] The cyclic highly water-resistant calcium carbonate coupling agent provided by the present invention can not only effectively surface-modify calcium carbonate powder, significantly reduce oil absorption, and improve dispersibility and fluidity, but also effectively solve the defect of easy hydrolysis of traditional borate coupling agents, thereby enhancing practicality, significantly improving the quality and added value of calcium carbonate powder and downstream products, and expanding the application field.

[0036] It should be noted that the above is a preferred embodiment of the present invention. For those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. Cyclic high water-resistant calcium carbonate coupling agent, characterized by: The synthesis method is as follows: boric acid and toluene are stirred, cycloheptanol is added dropwise over 1 hour, and then the temperature is raised to reflux for 6 hours; the mixture is cooled to room temperature, diethanolamine is added dropwise over 1 hour, and then the temperature is raised to reflux for 12 hours, and the toluene and diethanolamine are removed by vacuum distillation to obtain a cyclic highly water-resistant calcium carbonate coupling agent; The molar ratio of boric acid to cycloheptanol is 1:1; The molar ratio of the boric acid to diethanolamine is 0.4:0.4-0.5; the amount of the diethanolamine is 0.40-0.50 mol; The structural formula of the cyclic highly water-resistant calcium carbonate coupling agent is:

2. A method for synthesizing a cyclic highly water-resistant calcium carbonate coupling agent, characterized in that: Take boric acid and toluene, stir, add cycloheptanol dropwise, add completely over 1 hour, then heat and reflux for 6 hours; cool to room temperature, add diethanolamine dropwise, add completely over 1 hour, then heat and reflux for 12 hours, remove toluene and diethanolamine by vacuum distillation to obtain a cyclic highly water-resistant calcium carbonate coupling agent; The molar ratio of boric acid to cycloheptanol is 1:1; The molar ratio of the boric acid to diethanolamine is 0.4:0.4-0.5; the amount of the diethanolamine is 0.40-0.50 mol; The structural formula of the cyclic highly water-resistant calcium carbonate coupling agent is:

3. The use of the cyclic highly water-resistant calcium carbonate coupling agent according to claim 1 in the modification of calcium carbonate powder, characterized in that: Place the calcium carbonate powder in a modifier, heat and stir, and add a cyclic highly water-resistant calcium carbonate coupling agent to obtain highly activated calcium carbonate powder with excellent dispersibility and fluidity.

4. The use of the cyclic high water-resistant calcium carbonate coupling agent according to claim 3 in the modification of calcium carbonate powder, characterized in that: The amount of the dropwise added cyclic high water-resistant calcium carbonate coupling agent is 1.4-1.8% of the mass of the calcium carbonate powder.

5. The use of the cyclic high water-resistant calcium carbonate coupling agent according to claim 3 in the modification of calcium carbonate powder, characterized in that: The heating temperature is 80-90° C.; the stirring time is 15-20 minutes.

Images