Calcium hexahydrophthalate rigidifying nucleating agent, and preparation method and application thereof

Abstract

The application discloses a calcium hexahydrophthalate rigidifying nucleating agent and a preparation method and application thereof, and belongs to the field of plastic additives. The preparation method of the application uses a mixed solution of water and an organic solvent as a reaction solvent, which can effectively improve the solubility of raw materials and then improve the reaction efficiency. The preparation method of the application can prepare a calcium hexahydrophthalate rigidifying nucleating agent with uniform component distribution, which has single-water cis calcium hexahydrophthalate and anhydrous cis calcium hexahydrophthalate with different mass ratios. The nucleating agent can be applied to polypropylene modification, thereby realizing stable regulation and control of the performance of polypropylene products. The mass ratio of the single-water cis calcium hexahydrophthalate and the anhydrous cis calcium hexahydrophthalate in the nucleating agent can be determined by XRD.

Description

Technical Field

[0001] This invention belongs to the field of plastic additives, specifically relating to a calcium hexahydrophthalate stiffening nucleating agent, its preparation method, and its application. Background Technology

[0002] Thermoplastics are a widely used type of plastic product. These plastics melt upon heating, harden upon cooling, and can be repeatedly processed and recycled. Their properties are adjustable, and they possess excellent processing performance, high production efficiency, excellent electrical insulation and chemical resistance, and ease of lightweighting. They are used in everyday packaging, building pipes, automobiles, electronics, medical devices, textiles, and other fields. Polypropylene is a typical thermoplastic, but its crystallization temperature is relatively low and its crystallization time is relatively long, resulting in products whose rigidity does not meet the requirements of certain applications. Introducing nucleating agents into polypropylene to construct heterogeneous nucleation is a common method to improve the crystallization and mechanical properties of polypropylene. Under the action of heterogeneous nuclei, the crystallization induction period of polypropylene is shortened, the crystallization temperature is increased, the crystallization rate is accelerated, and a large number of uniformly sized and stable spherulites are formed, significantly improving the rigidity of the product and balancing toughness.

[0003] Commonly used stiffening nucleating agents include HPN20e, HPN68L, and NA21, among which HPN20e, representing calcium hexahydrophthalate (CHP), is a typical stiffening nucleating agent. This type of nucleating agent can effectively increase the crystallization rate, improve the rigidity of the product, and balance toughness, achieving a balance between stiffness and toughness. Patent CN1292018C discloses a method for synthesizing CHP in a saline environment. In an aqueous environment, CHP readily combines with one molecule of water of crystallization to obtain CHP monohydrate. Studies have shown that anhydrous CHP and CHP monohydrate have different effects on the modification of polypropylene. The properties of polypropylene products can be adjusted by simply physically mixing anhydrous CHP and CHP monohydrate. However, physical mixing may result in uneven mixing, leading to unstable performance adjustment. Summary of the Invention

[0004] In view of the above background, the purpose of this invention is to provide a calcium hexahydrophthalate-based stiffening nucleating agent, its preparation method, and its application. This method can directly prepare a calcium hexahydrophthalate-based stiffening nucleating agent in which monohydrated cis-hexahydrophthalate and anhydrous cis-hexahydrophthalate are uniformly mixed at different mass ratios. Applying this nucleating agent to polypropylene modification can achieve the purpose of adjusting the properties of polypropylene products.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a calcium hexahydrophthalate-based nucleating agent includes the following steps: (1) Dissolve calcium hydroxide in the reaction solvent, add cis-hexahydrophthalic anhydride, the molar ratio of cis-hexahydrophthalic anhydride to calcium hydroxide is 1:1, and stir the reaction at a certain temperature for a period of time.

[0006] (2) Filter the reaction mixture and dry the filter residue under vacuum at room temperature for 2 h to obtain calcium cis-hexahydrophthalic acid monohydrate; (3) The calcium monohydrate cis-hexahydrophthalic acid is dried at a certain temperature for a certain time to obtain the calcium hexahydrophthalic acid-based stiffening nucleating agent.

[0007] Further, in step (1), the reaction solvent is a mixture of water and an organic solvent in a volume ratio of 1:1, wherein the organic solvent is one or more of methanol, ethanol, isopropanol, acetone, tetrahydrofuran, and acetonitrile.

[0008] Furthermore, in step (1), the reaction temperature is 25-80℃ and the reaction time is 1-12 h.

[0009] Furthermore, in step (2), the vacuum drying temperature is room temperature or ambient temperature.

[0010] Furthermore, in step (3), the drying temperature is 50-200℃ and the drying time is 10 min-24 h.

[0011] Furthermore, the nucleating agent is composed of calcium monohydrate and calcium anhydrous cis-hexahydrophthalate in different mass ratios, wherein the mass fraction of calcium monohydrate is 0-100%, preferably 30%-70%.

[0012] The ratio of the two calcium salts in the nucleating agent was determined by the peak height ratio of the main diffraction peaks of monohydrate and anhydrous cis-hexahydrophthalic acid calcium by XRD analysis of the obtained calcium hexahydrophthalic acid calcium nucleating agent.

[0013] Application: The application of the calcium hexahydrophthalate-based stiffening nucleating agent in polypropylene modification: By adjusting the mass ratio of monohydrated cis-hexahydrophthalate and anhydrous cis-hexahydrophthalate in the nucleating agent, the crystallization temperature and mechanical properties of the modified polypropylene can be adjusted.

[0014] The beneficial effects of this invention are: (1) The preparation method of the present invention uses a mixed solution of water and organic solvent as the reaction solvent, which can effectively improve the solubility of raw materials and thus improve the reaction efficiency.

[0015] (2) The preparation method of the present invention can prepare a calcium hexahydrophthalate-based stiffening nucleating agent by adjusting the drying time and temperature. In this nucleating agent, monohydrated cis-hexahydrophthalate and anhydrous cis-hexahydrophthalate are uniformly mixed at different mass ratios. Applying this nucleating agent to the modification of polypropylene can achieve stable control of the properties of polypropylene products. Attached Figure Description

[0016] Figure 1 The image shows the XRD pattern of the nucleating agent obtained in Example 1. Figure 2 The image shows the XRD pattern of the nucleating agent obtained in Example 2. Figure 3 The image shows the XRD pattern of the nucleating agent obtained in Example 7. Detailed Implementation

[0017] A method for preparing a calcium hexahydrophthalate-based nucleating agent includes the following steps: (1) Dissolve calcium hydroxide in the reaction solvent, add cis-hexahydrophthalic anhydride, the molar ratio of cis-hexahydrophthalic anhydride to calcium hydroxide is 1:1, and stir the reaction at 25-80℃ for 1-12 h.

[0018] (2) Filter the reaction mixture and dry the filter residue under vacuum at room temperature for 2 h to obtain calcium cis-hexahydrophthalic acid monohydrate; (3) The calcium monohydrate cis-hexahydrophthalic acid calcium is heated at 50-200℃ for 10 min-24 h to obtain the calcium hexahydrophthalic acid calcium-based stiffening nucleating agent.

[0019] The ratio of the two calcium salts in the nucleating agent was determined by the peak height ratio of monohydrate cis-hexahydrophthalic acid calcium and anhydrous cis-hexahydrophthalic acid calcium by XRD analysis of the obtained calcium hexahydrophthalic acid calcium nucleating agent.

[0020] In step (1), the reaction solvent is a mixture of water and an organic solvent in a volume ratio of 1:1. The organic solvent is one or more of methanol, ethanol, isopropanol, acetone, tetrahydrofuran, and acetonitrile.

[0021] The obtained calcium hexahydrophthalate nucleating agents were analyzed by XRD. The main diffraction peak of monohydrate cis-hexahydrophthalate calcium was 7.3, and that of anhydrous cis-hexahydrophthalate calcium was 6.7. The ratio of the two calcium salts in the nucleating agent was determined by the peak height ratio of the two diffraction peaks. Example 1

[0022]

[0023] Calcium hydroxide (2.40 g, 32.4 mmol) was dissolved in 20 mL of a mixed solvent of water and ethanol (volume ratio 1:1), and cis-hexahydrophthalic anhydride (5.00 g, 32.4 mmol) was added. The mixture was stirred at 50 °C for 5 h. The reaction mixture was filtered, and the residue was dried under vacuum at room temperature for 2 h to obtain 6.96 g of solid, with a yield of 94.0%. The dried solid was dried at 50 °C for 24 h to obtain a calcium hexahydrophthalate-based nucleating agent. XRD analysis showed that this nucleating agent contained only calcium hexahydrophthalate monohydrate. Example 2

[0024] The specific operation of this embodiment is the same as that of Example 1, except that the dried solid is dried at 110°C for 5 h. The resulting calcium hexahydrophthalate-based hardening nucleating agent was tested by XRD and found to contain monohydrate cis-hexahydrophthalate calcium and anhydrous cis-hexahydrophthalate calcium, with a mass ratio of monohydrate cis-hexahydrophthalate calcium to anhydrous cis-hexahydrophthalate calcium of 7:3. Example 3

[0025] The specific operation of this embodiment is the same as that of Example 1, except that the dried solid is dried at 130°C for 2 hours. The resulting calcium hexahydrophthalate-based hardening nucleating agent was tested by XRD and found to contain monohydrate cis-hexahydrophthalate calcium and anhydrous cis-hexahydrophthalate calcium, with a mass ratio of 5:5 between monohydrate and anhydrous cis-hexahydrophthalate calcium. Example 4

[0026] The specific operation of this embodiment is the same as that of Example 1, except that the dried solid is dried at 160°C for 1 h. The resulting calcium hexahydrophthalate-based hardening nucleating agent was tested by XRD and found to contain monohydrate cis-hexahydrophthalate calcium and anhydrous cis-hexahydrophthalate calcium, with a mass ratio of monohydrate cis-hexahydrophthalate calcium to anhydrous cis-hexahydrophthalate calcium of 3:7. Example 5

[0027] The specific operation of this embodiment is the same as that of Example 1, except that the reaction is carried out at 80°C for 1 hour. The reaction yield is 95.1%. The calcium hexahydrophthalate nucleating agent obtained after drying is found by XRD testing to contain only calcium monohydrate cis-hexahydrophthalate. Example 6

[0028] Calcium hydroxide (1.44 kg, 19.4 mol) was dissolved in 20 L of a mixed solvent of water and acetone (volume ratio 1:1), and cis-hexahydrophthalic anhydride (3.00 kg, 19.4 mol) was added. The mixture was stirred at 25 °C for 12 h. The reaction mixture was filtered, and the residue was dried under vacuum at room temperature for 2 h to obtain 4.21 kg of solid, with a yield of 94.8%. The dried solid was dried at 80 °C for 12 h to obtain a calcium hexahydrophthalate-based nucleating agent. XRD analysis showed that this nucleating agent contained only calcium hexahydrophthalate monohydrate. Example 7

[0029] The specific operation of this embodiment is the same as that of Example 6, except that the dried solid is dried at 200°C for 10 min. The resulting calcium hexahydrophthalate nucleating agent was tested by XRD and found to contain only anhydrous cis-calcium hexahydrophthalate.

[0030] Comparative Example 1

[0031] Calcium hydroxide (2.40 g, 32.4 mmol) was dissolved in 20 mL of water, and cis-hexahydrophthalic anhydride (5.00 g, 32.4 mmol) was added. The mixture was stirred at 50 °C for 5 h. The reaction mixture was filtered, and the residue was dried under vacuum at room temperature for 2 h to obtain 5.79 g of solid, with a yield of 78.2%. The dried solid was dried at 50 °C for 24 h to obtain a calcium hexahydrophthalate-based nucleating agent. XRD analysis showed that this nucleating agent contained only calcium hexahydrophthalate monohydrate.

[0032] A calcium hexahydrophthalate-based stiffening and nucleating agent was added to the base material of polypropylene L5E89. After uniform mixing, the mixture was extruded and granulated, and its crystallization temperature was tested. The remaining modified material was injection molded into test strips, placed in a constant temperature and humidity chamber at 23℃ for 48 hours, and then its performance was tested. The test results are shown in the table below:

[0033] Experiments in groups 1-5 of the table used a mixture or pure substance of anhydrous cis-hexahydrophthalic acid calcium and monohydrate cis-hexahydrophthalic acid calcium prepared using the method of this patent. Experiments in groups 6-10 of the table used a mixture obtained by simple physical mixing of anhydrous cis-hexahydrophthalic acid calcium and monohydrate cis-hexahydrophthalic acid calcium. The data in the table show that when using the mixture prepared by the method of this patent, the higher the content of anhydrous cis-hexahydrophthalic acid calcium in the nucleating agent, the higher the crystallization temperature of the modified polypropylene, the stronger its rigidity, and the greater its flexural modulus, while the impact strength and tensile strain at fracture decrease accordingly. However, the performance of the modified polypropylene obtained by simple physical mixing did not show a regular change with the composition of the nucleating agent.

[0034] The nucleating agents used in experiments group 2 and group 7 in the table were subjected to XRD tests. Each sample was tested in triplicate, and the peak height ratio of the main diffraction peaks of anhydrous calcium cis-hexahydrophthalate and calcium cis-hexahydrophthalate monohydrate was calculated. The results are shown in the table below:

[0035] The data in the table show that the anhydrous calcium cis-hexahydrophthalate and calcium cis-hexahydrophthalate mixture prepared by simple physical mixing has poorer homogeneity than the mixture prepared by the method of this patent.

[0036] In summary, the method of this patent can prepare a mixture of anhydrous cis-hexahydrophthalic acid calcium and monohydrate cis-hexahydrophthalic acid calcium, wherein the anhydrous cis-hexahydrophthalic acid calcium and monohydrate cis-hexahydrophthalic acid calcium are uniformly mixed in different mass ratios, thereby achieving stable control of the properties of polypropylene.

[0037] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a calcium hexahydrophthalate-based nucleating agent, characterized in that, Includes the following steps: (1) Dissolve calcium hydroxide in the reaction solvent, add cis-hexahydrophthalic anhydride, and stir the reaction at a certain temperature for a period of time; (2) Filter the reaction mixture and dry the filter residue under vacuum at room temperature for 2 h to obtain calcium cis-hexahydrophthalic acid monohydrate; (3) The calcium monohydrate cis-hexahydrophthalic acid is dried at a certain temperature for a certain time to obtain the calcium hexahydrophthalic acid-based stiffening nucleating agent.

2. The preparation method according to claim 1, characterized in that, The nucleating agent is composed of calcium monohydrate cis-hexahydrophthalic acid and anhydrous calcium monohydrate in different mass ratios, wherein the mass fraction of calcium monohydrate cis-hexahydrophthalic acid is 0-100%.

3. The preparation method according to claim 1, characterized in that, The reaction solvent is a mixture of water and an organic solvent in a volume ratio of 1:1, wherein the organic solvent is one or more of methanol, ethanol, isopropanol, acetone, tetrahydrofuran, and acetonitrile.

4. The preparation method according to claim 1, characterized in that, The reaction temperature is 25-80℃, and the reaction time is 1-12 h.

5. The preparation method according to claim 1, characterized in that, The drying temperature is 50-200℃, and the drying time is 10 min-24 h.

6. A calcium hexahydrophthalate nucleating agent prepared by the preparation method according to any one of claims 1-5.

7. The application of the calcium hexahydrophthalate-based stiffening nucleating agent according to claim 6 in the modification of polypropylene, characterized in that, The crystallization temperature and mechanical properties of the modified polypropylene were adjusted by regulating the mass ratio of monohydrated cis-hexahydrophthalic acid calcium to anhydrous cis-hexahydrophthalic acid calcium in the nucleating agent.

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