A class of amide-based β-nucleating agents for polyacrylonitrile and their preparation methods

Abstract

This invention relates to a class of amide-based β-nucleating agents for polypropylene and their preparation methods. These nucleating agents are carboxylate complexes with amide structures synthesized by reacting tetrahydrophthalic anhydride with 1,4-cyclohexanediamine. The complexes are obtained by a semi-solid reaction of the amide product with a metal hydroxide under organic solvent conditions. These nucleating agents can increase the crystallization peak temperature of polypropylene and exhibit high β-crystal-induced nucleation efficiency. The β-crystal content in polypropylene modified with these nucleating agents reaches up to 96.3%, and the agents are characterized by low dosage, low production cost, high efficiency, and good stability.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis and functional materials technology, specifically to a class of amide-based β-nucleating agents, their preparation methods, and their application in polypropylene nucleation. Background Technology

[0002] Polypropylene (PP) is a thermoplastic semi-crystalline resin material with propylene as its monomer. In the 1950s, Natta, building on Ziegler's research, first synthesized polypropylene with high regularity. In the 1960s, the Italian company Montecatini commercialized polypropylene, marking the beginning of its industrial applications. As a general-purpose resin material, polypropylene possesses excellent mechanical properties, superior insulation properties, ease of processing, and environmental friendliness, making it widely used in chemical, automotive, home appliance, building materials, daily consumer goods, and textile industries. For over sixty years, polypropylene has been the world's second-largest consumer of thermoplastic resin materials. In 2020, global polypropylene production reached over 91 million tons, and domestic consumption in China reached 40 million tons by the end of 2022. With economic development and improved living standards, people's demands for material conditions are increasing, and polypropylene, applicable to all aspects of life including clothing, food, housing, and transportation, is increasingly driving up both production and consumption.

[0003] Polypropylene can be classified into isotactic polypropylene (iPP), syndiotactic polypropylene (sPP), and atactic polypropylene (aPP) based on its spatial arrangement; and into five crystal forms—α, β, γ, δ, and pseudo-hexagonal—based on its crystal arrangement and spherulite morphology. Currently, the α and β crystal forms are the most widely used in practical applications. The α crystal form is a monoclinic crystal system with the following cell parameters: Alpha-crystalline polypropylene is thermodynamically stable and can be produced during conventional processing. It possesses high tensile strength and flexural modulus, but its impact strength is relatively poor, limiting its applications. Beta-crystalline polypropylene is hexagonal, with the following unit cell parameters: β-crystalline polypropylene is thermodynamically unstable and therefore not easily generated kinetically; it requires processing under specific conditions to obtain it.

[0004] Nucleating agents are substances that improve the crystallization properties of polypropylene. Adding nucleating agents during the blending process is a common method to improve the processing and mechanical properties of polypropylene. The addition of nucleating agents can increase the crystallization temperature of polypropylene, shorten the crystallization time, and enhance mechanical properties. Based on their properties, nucleating agents can be classified into α-nucleating agents and β-nucleating agents.

[0005] Polypropylene α-nucleating agents can be mainly classified into inorganic nucleating agents, organic nucleating agents, and polymeric nucleating agents.

[0006] 1. Inorganic α-nucleating agents are mainly inorganic fillers, such as kaolin, talc, and magnesium oxide. These nucleating agents can increase the crystallization peak temperature of polypropylene, but they are difficult to disperse in the matrix.

[0007] 2. Organic α-nucleating agents can be classified into sorbitols, aromatic carboxylates, organophosphates, and rosins. They can improve the crystallization temperature, transparency, and heat distortion temperature of polypropylene, but their synthesis cost is relatively high.

[0008] 3. Polymer-based α-nucleating agents are currently not technologically mature and there are no industrialized products yet.

[0009] Polypropylene β-nucleating agents can be mainly classified into inorganic nucleating agents, organic nucleating agents, and polymeric nucleating agents.

[0010] 1. Inorganic β-nucleating agents: These nucleating agents mainly include ZnO, La2O3, CaCO3, etc. They have poor compatibility with polypropylene melt, uneven dispersion, and are prone to agglomeration. The amount added is larger than that of other nucleating agents and the nucleation effect is poor; therefore, their application is limited.

[0011] 2. Organic β-nucleating agents

[0012] 2.1 Fused ring nucleating agents: Fused ring nucleating agents were the earliest discovered nucleating agents. However, due to their large conjugated structures, which are often colored and require large amounts, their nucleation effect is poor, thus limiting their application.

[0013] 2.2 Organic carboxylic acids and their salts nucleating agents: mainly organic dicarboxylic acid salt nucleating agents such as succinate, adipate, and terephthalate. These nucleating agents have relatively high nucleation effects, but they have poor thermal stability and are prone to decomposition at high temperatures. In addition, these nucleating agents have high production costs, which limits their industrial applications.

[0014] 2.3 Amide Nucleating Agents: Amide nucleating agents include aromatic amide nucleating agents and aliphatic amide nucleating agents. First discovered by Shinraika Co., Ltd. of Japan in the 1990s, they have been extensively studied. Amide nucleating agents have good compatibility with polypropylene and excellent nucleation effects. Aromatic nucleating agents, due to their good nucleation effect and high thermal stability, have already seen some products commercialized; however, they have disadvantages such as requiring the use of some toxic and harmful chemical reagents during production.

[0015] 3. Rare Earth Nucleating Agents: Rare earth nucleating agents are a type of nucleating agent based on rare earth element carboxylates, independently developed in my country. Main products include WBG-1 and WBG-2, which feature low dosage, no coloring, and good thermal stability. They are currently commercialized and widely used. However, their structure and nucleation mechanism are still unclear.

[0016] 4. Polymer-based nucleating agents: Polymer-based nucleating agents are a new type of polypropylene β-nucleating agent discovered in the last decade. Because polymer-based nucleating agents have similar structures to polypropylene solvents, they exhibit better dispersibility in polypropylene according to the principle of "like dissolves like," and their compatibility is superior to other nucleating agents. For example, ethylene and styrene-acrylonitrile copolymers can induce β-crystal formation in polypropylene. However, currently discovered polymer-based nucleating agents have poor nucleation efficiency and require high dosages, leading to two problems: 1) High dosage of nucleating agent means higher cost; 2) The amount of nucleating agent added affects the mechanical properties, gloss, rheological properties, and other physical properties of the polypropylene base material. Therefore, the application prospects of this type of nucleating agent are very limited.

[0017] CN114773673A, "An Amide β-Crystal Nucleating Agent and Its Application," utilizes hexahydrophthalic anhydride and p-phenylenediamine as raw materials to synthesize amide carboxylic acids, which are then reacted with a metal salt solution to prepare amide carboxylate nucleating agents. However, this method may result in incomplete reactions of the raw materials, i.e., the coexistence of monoamides and diamides. Furthermore, sodium bicarbonate needs to be added dropwise to adjust the pH during salt formation, making the process complex, and the final synthesized product exhibits poor heat resistance.

[0018] CN113292787A, entitled "A β-Crystal Nucleating Agent and Its Preparation Method and Application," utilizes tetrahydrophthalic anhydride and p-phenylenediamine as raw materials to synthesize amide carboxylic acids, which are then reacted with a metal salt solution to prepare amide carboxylate nucleating agents. However, this method suffers from incomplete reaction due to excessive amine in the raw materials. Salt formation also requires the addition of sodium bicarbonate to adjust the pH, making the process complex. Its heat resistance and β-nucleation effect in homopolymer polypropylene have not been reported. Summary of the Invention

[0019] The purpose of this invention is to provide a class of amide-based β-nucleating agents, their preparation methods, and their application in polypropylene materials.

[0020] This application utilizes an amidation reaction between tetrahydrophthalic anhydride and 1,4-cyclohexanediamine to obtain amide carboxylic acid compounds. The amide structure introduces a dicarboxyl group into the traditional amide structure, further reacting with metal hydroxides to form salts, achieving a synergistic effect between the amide and carboxylic acid structures. This nucleating agent exhibits milder synthesis conditions than traditional amide nucleating agents, eliminating the need for highly polluting organic acylation agents and solvents such as N,N'-dimethylformamide, sulfoxide, oxalyl chloride, and pyridine, resulting in a simpler production process and easier industrialization. Furthermore, this invention is the first to utilize a semi-solid method, directly using more basic hydroxides for salt formation, improving the utilization rate of metal atoms while reducing the number of salt formation steps. This novel nucleating agent has a well-defined and simple molecular structure, good thermal stability, and requires only a small dosage. It can increase the crystallization peak temperature and crystallization temperature of polypropylene, while also exhibiting high β-crystal-induced nucleation efficiency; the β-crystal content in polypropylene modified with this nucleating agent reaches as high as 96.3%.

[0021] The technical solution adopted in this invention is:

[0022] A type of amide-based β-nucleating agent for polypropylene, wherein the β-nucleating agent is an aliphatic amide carboxylic acid product obtained by amidation reaction of tetrahydrophthalic anhydride and 1,4-cyclohexanediamine in an organic solvent, dissolving the product in an organic solvent, and reacting it with a metal hydroxide in a semi-solid reaction.

[0023] The structure of the amide carboxylic acid product is shown in Formula I, and the structure of the aliphatic amide carboxylic acid salt product is shown in Formula II:

[0024]

[0025]

[0026] The general formula of the β-nucleating agent is represented by Formula II, where M represents one of calcium, magnesium, lanthanum, zinc, and barium, and x is 2 or 3.

[0027] The preparation method of the β-nucleating agent of the present invention includes the following steps:

[0028] (1) Tetrahydrophthalic anhydride and 1,4-cyclohexanediamine were dissolved in an organic solvent to carry out an amidation reaction to obtain a crude product with an amide structure. Unreacted impurities were removed by washing with an organic solvent multiple times to obtain an amide carboxylic acid structure product, i.e. Formula I.

[0029] (2) After dissolving the above amide carboxylic acid structure product in an organic solvent, add the corresponding metal hydroxide to carry out a semi-solid reaction. After the reaction is completed, remove the organic solvent by vacuum distillation to obtain the aliphatic amide carboxylic acid salt product, namely Formula II.

[0030] Further, in step (1), the molar ratio of tetrahydrophthalic anhydride to 1,4-cyclohexanediamine is (2.1-2.5):1.

[0031] Further, in step (1), when tetrahydrophthalic anhydride undergoes an amidation reaction with 1,4-cyclohexanediamine, the organic solvent is at least one of chloroform, tetrahydrofuran, methanol, acetone, benzene, and toluene.

[0032] Furthermore, in step (1), the reaction between tetrahydrophthalic anhydride and 1,4-cyclohexanediamine is carried out at room temperature for 12–24 h.

[0033] Further, in step (2), the metal hydroxide is at least one of calcium hydroxide, magnesium hydroxide, lanthanum hydroxide, zinc hydroxide, and barium hydroxide.

[0034] Furthermore, in step (2), the molar ratio of the amide carboxylic acid structural product to the metal hydroxide is 3:(2-3).

[0035] Furthermore, in step (2), when the amide carboxylic acid product reacts with the metal hydroxide in a semi-solid reaction, the organic solvent is at least one of methanol, dimethyl sulfoxide, n-hexane, and benzene.

[0036] Furthermore, in step (2), the reaction between the amide carboxylic acid product and the metal hydroxide is carried out at room temperature for 8 to 24 hours.

[0037] The β-nucleating agent prepared by the above method can increase the crystallization peak temperature of isotactic homopolymer polypropylene (iPP-T30S) and has a high β-crystal-induced nucleation efficiency. The β-crystal content in polypropylene modified by this type of nucleating agent is as high as 96.3%, and it has the characteristics of low dosage, low production cost, high efficiency and good stability.

[0038] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0039] (1) The molar ratio of tetrahydrophthalic anhydride and cyclohexanediamine in this invention is 2.1 to 2.5:1, which can fully ensure the reaction is complete and ensure that both amino groups of the diamine can be amidated, thereby reducing the formation of monoamide carboxylic acid.

[0040] (2) The heat resistance temperature of the material synthesized in this invention exceeds 250°C, which can fully meet the production and processing conditions of polypropylene.

[0041] (3) The present invention utilizes a semi-solid method and the corresponding hydroxide to react directly, reducing the salt formation reaction steps and the use of solvents, which is beneficial to industrial production.

[0042] (4) The nucleating agent synthesized in this invention has a high β-induction efficiency, which can reach at least 60% and up to 96.3% β-crystal conversion rate.

[0043] In summary, this invention has developed a nucleating agent for polypropylene with an amide structure, which can increase the crystallization peak temperature of polypropylene or induce the formation of β-spherulites. This provides a new product development approach for industrial production and opens up new avenues for exploring the structure of amide-based nucleating agents, offering valuable insights and references. It also solves production problems related to early-stage structural exploration. The nucleating agent of this invention can be synthesized at room temperature under mild conditions, using fewer toxic and harmful reagents, and has low raw material costs. Furthermore, the nucleating agent exhibits good thermal stability, resulting in a high β-crystal content in modified polypropylene. It demonstrates excellent performance in isotactic homopolymer polypropylene (iPP-T30S), has a wide range of applications, and shows promising prospects for industrial application. Attached Figure Description

[0044] Figure 1 This is the hydrogen NMR spectrum of NA.

[0045] Figure 2 The infrared spectra of NA with nucleating agents NA-Ca, NA-Mg, NA-La, NA-Zn, and NA-Ba are shown.

[0046] Figure 3 This is the TG weightlessness plot for NA.

[0047] Figure 4 Comparison chart of DSC test results for NA-Ca salt and NA-Mg salt.

[0048] Figure 5 Comparison charts of DSC tests applied to NA-La salt, NA-Zn salt, and NA-Ba salt.

[0049] Figure 6 Comparison chart of DSC test results for compound nucleating agents. Detailed Implementation

[0050] The present invention will be further explained and described below with reference to specific embodiments and accompanying drawings.

[0051] Example 1

[0052] A type of amide carboxylate β-nucleating agent for polyacrylamide is prepared by the following steps:

[0053] (1) 0.025 mol of tetrahydrophthalic anhydride was added to a 250 mL flask containing 60 mL of tetrahydrofuran. Then, 0.01 mol of 1,4-cyclohexanediamine was added in portions to the reaction solution. After reacting at room temperature for 24 h, a white precipitate formed in the solvent. Centrifugation yielded a white solid crude product. The crude product was washed with 30 mL of tetrahydrofuran and purified by centrifugation until NMR detection showed no impurities. It was then placed in a vacuum drying oven at 60 °C for 12 h until the product's mass no longer changed, yielding the intermediate product NA. The 1H NMR spectrum and structural formula of NA are shown below. Figure 1 As shown. The structural formula of the product is:

[0054]

[0055] (2) 15 mmol of NA was added to a 100 mL flask containing 50 mL of methanol, followed by the addition of 15 mmol of calcium hydroxide. The mixture was reacted at room temperature for 12 h. The methanol solvent was removed by vacuum distillation to obtain a white solid. This solid was then dried in a vacuum oven at 100 °C for 12 h until the product's mass no longer changed, yielding the nucleating agent NA-Ca with the following structural formula:

[0056]

[0057] Example 2

[0058] A type of amide carboxylate β-nucleating agent for polyacrylamide is prepared by the following steps:

[0059] (1) 0.023 mol of tetrahydrophthalic anhydride was added to a 250 mL flask containing 60 mL of chloroform. Then, 0.01 mol of 1,4-cyclohexanediamine was added to the reaction solution in portions. After reacting at room temperature for 12 h, a white precipitate was formed in the solvent. The white solid crude product was obtained by centrifugation. The crude product was washed with 30 mL of chloroform and purified by centrifugation until no impurities were detected by NMR. The product was then placed in a vacuum drying oven at 60 °C for 12 h until the quality of the product no longer changed. The intermediate product NA was finally obtained.

[0060] (2) 15 mmol of NA was added to a 100 mL flask containing 50 mL of ethanol, followed by the addition of 15 mmol of magnesium hydroxide. The mixture was reacted at room temperature for 24 h. The ethanol solvent was removed by vacuum distillation to obtain a white solid. This solid was then dried in a vacuum oven at 100 °C for 12 h until the product's mass no longer changed, yielding the nucleating agent NA-Mg with the following structural formula:

[0061]

[0062] Example 3

[0063] A type of amide carboxylate β-nucleating agent for polyacrylamide is prepared by the following steps:

[0064] (1) 0.021 mol of tetrahydrophthalic anhydride was added to a 250 mL flask containing 60 mL of toluene. Then, 0.01 mol of 1,4-cyclohexanediamine was added to the reaction solution in portions. After reacting at room temperature for 18 h, a white precipitate was formed in the solvent. The white solid crude product was obtained by centrifugation. The crude product was washed with 30 mL of diethyl ether and purified by centrifugation until no impurities were detected by NMR. The product was then placed in a vacuum drying oven at 60 °C for 12 h until the quality of the product no longer changed. The intermediate product NA was finally obtained.

[0065] (2) 15 mmol of NA was added to a 100 mL flask containing 50 mL of dimethyl sulfoxide, followed by the addition of 10 mmol of lanthanum hydroxide. The reaction was carried out at room temperature for 16 h. The dimethyl sulfoxide solvent was removed by vacuum distillation to obtain a white solid. This solid was then dried in a vacuum oven at 100 °C for 12 h until the product's mass no longer changed, finally yielding the nucleating agent NA-La, with the following structural formula:

[0066]

[0067] Example 4

[0068] A type of amide carboxylate β-nucleating agent for polyacrylamide is prepared by the following steps:

[0069] (1) 0.022 mol of tetrahydrophthalic anhydride was added to a 250 mL flask containing 60 mL of methanol. Then, 0.01 mol of 1,4-cyclohexanediamine was added to the reaction solution in portions. After reacting at room temperature for 16 h, a white precipitate was formed in the solvent. The white solid crude product was obtained by centrifugation. The crude product was washed with 30 mL of methanol and purified by centrifugation until no impurities were detected by NMR. Then, it was placed in a vacuum drying oven and dried at 60 °C for 12 h until the quality of the product no longer changed. Finally, the intermediate product NA was obtained.

[0070] (2) 15 mmol of NA was added to a 100 mL flask containing 50 mL of n-hexane, followed by the addition of 15 mmol of zinc hydroxide. The reaction was carried out at room temperature for 18 h. The n-hexane solvent was removed by vacuum distillation to obtain a white solid. This solid was then dried in a vacuum oven at 100 °C for 12 h until the product's quality no longer changed, ultimately yielding the nucleating agent NA-Zn, with the following structural formula:

[0071]

[0072] Example 5

[0073] A type of amide carboxylate β-nucleating agent for polyacrylamide is prepared by the following steps:

[0074] 1. Add 0.022 mol of tetrahydrophthalic anhydride to a 250 mL flask containing 60 mL of tetrahydrofuran. Then, add 0.01 mol of 1,4-cyclohexanediamine to the reaction solution in portions. After reacting at room temperature for 20 h, a white precipitate is formed in the solvent. Centrifuge to obtain a white solid crude product. Wash the crude product with 30 mL of tetrahydrofuran and centrifuge to purify it until NMR detection shows no impurities. Then place it in a vacuum drying oven at 60 °C for 12 h until the quality of the product no longer changes, and finally obtain the intermediate product NA.

[0075] 2. Add 15 mmol of NA to a 100 mL flask containing 50 mL of benzene, then add 15 mmol of barium hydroxide. React at room temperature for 8 hours. Remove the benzene solvent by vacuum distillation to obtain a white solid. Then place it in a vacuum drying oven at 120 °C for 12 hours until the product's quality no longer changes, finally obtaining the nucleating agent NA-Ba, with the following structural formula:

[0076]

[0077] Figure 2 The images show the infrared spectra of nucleating agents NA-Ca, NA-Mg, NA-La, NA-Zn, and NA-Ba. It can be seen that by comparing the infrared spectra of NA with the products after the semi-solid conversion, the characteristic absorption peaks of the NH, C=O, and CN structures of the amide structure did not change significantly before and after the conversion, indicating that the amide structure remained stable before and after mixing. After mixing NA with metal hydroxide via the semi-solid method for 24 hours, the infrared spectrum at 1400 cm⁻¹... -1 1560cm -1 The appearance of new absorption peaks on the left and right indicates the presence of COO-, suggesting the formation of the corresponding carboxylate.

[0078] Figure 3 The image shows the TG weight loss plot of NA. It can be seen that NA has a high heat resistance temperature, exceeding 250℃ from the decomposition curve, which meets the processing requirements of polypropylene.

[0079] Application examples

[0080] The following describes the performance of the nucleating agents NA-Ca, NA-Mg, NA-La, NA-Zn, and NA-Ba prepared in Examples 1-5 for polypropylene nucleation.

[0081] The common components are as follows (by weight):

[0082] Polypropylene, grade T30S powder, 100 parts; antioxidant 168, 0.1 parts; antioxidant 1010, 0.05 parts; calcium stearate, 0.1 parts.

[0083] Nucleating agents were added according to Table 1, for a total of 18 experiments. The data in the table are the number of parts added by weight.

[0084] Table 1. Different nucleating agent formulations

[0085]

[0086]

[0087] The above formula was added to a torque rheometer for intensive mixing. The torque rheometer parameters were: temperature of 200℃ in all four zones, rotation speed of 50 r / min, and mixing for 500 s to obtain the final test sample. The DSC curve was tested using a differential scanning calorimeter. The DSC curve test conditions were: heating rate of 10℃ / min, heating from 50℃ to 210℃, holding the temperature for 4 min, then cooling to 50℃, holding the temperature for 4 min, and then heating from room temperature to 210℃. The first heating and holding were to eliminate thermal history. The test results were taken from the crystallization curve after the first cooling and the melting curve after the second heating. The temperature range was 50~210℃.

[0088] The β crystal content was calculated using the DSC method. Two peak areas were obtained by fitting the data using the built-in software's integral calculation, representing ΔH respectively. β and ΔH α Substitute into the formula in Given the standard enthalpy for the corresponding crystal forms, the standard enthalpies for β-crystal and α-crystal are 170 J / g and 178 J / g, respectively. Calculate the crystallinity X of β-crystal and α-crystal. β and X α Then use the formula Calculate the β crystal conversion rate (i.e., β-crystal content). The β-crystal content of each application formulation was calculated using the method described above, as shown in Table 2. The DSC test results for each nucleating agent's individual application formulation are as follows: Figure 4 , Figure 5 As shown, barium salts exhibit superior β-nucleation induction compared to other metal salts used alone. DSC tests of various nucleating agent combination formulations are shown below. Figure 6 As shown, barium / calcium, barium / lanthanum, and barium / zinc complexes exhibit excellent effects in inducing β-nucleation.

[0089] The test results are shown in Table 2:

[0090] Table 2. Test results of β-crystal content for different nucleating agent formulations

[0091]

[0092]

[0093] Table 2 shows that adding nucleating agents alone indicates that the newly synthesized tetrahydrophthalic anhydride amide carboxylic acid metal salts have a β-induced nucleation effect, with β-crystal contents all above 68%. A comparative analysis revealed that barium salt alone exhibited the best β-crystal nucleation effect, reaching 92.24%. This is because barium salts have a larger atomic size, resulting in a higher degree of matching between their spatial structure and the lattice parameters of polypropylene β-crystals after salt formation, making it easier to induce β-crystal formation. Combining amide carboxylic acids revealed excellent synergistic effects with barium / calcium, barium / lanthanum, and barium / zinc, achieving β-crystal contents of 96.2%, 95.2%, and 93.5%, respectively. This may be related to the formation of multi-coordinate metals after metal salt combination, where a single metal ion may complex with multiple acid radicals, and some π-bond structures exist between the acid radicals, thus elongating its spatial c-axis and better matching the lattice parameters of polypropylene β-crystals, thereby inducing the formation of more β-crystals.

[0094] The above embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or evolutions made without departing from the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. A class of β-nucleating agents, characterized in that, The β-nucleating agent refers to an aliphatic amide carboxylic acid product obtained by amidation reaction of tetrahydrophthalic anhydride and 1,4-cyclohexanediamine in an organic solvent, followed by dissolving the product in an organic solvent and reacting it with a metal hydroxide via a semi-solid reaction. The structure of the amide carboxylic acid product is shown in Formula I, and the structure of the aliphatic amide carboxylic acid salt product is shown in Formula II: The general formula of the β nucleating agent is represented by Formula II, where M represents one of calcium, magnesium, lanthanum, zinc, and barium, and x is 2 or 3; the nucleating agent has high β-induction efficiency, and can achieve a maximum β crystal conversion rate of 96.3%.

2. The method for preparing the β-nucleating agent according to claim 1, characterized in that, Includes the following steps: (1) Tetrahydrophthalic anhydride and 1,4-cyclohexanediamine were dissolved in an organic solvent to carry out an amidation reaction to obtain a crude product with an amide structure. Unreacted impurities were removed by washing with an organic solvent multiple times to obtain an amide carboxylic acid structure product, i.e. Formula I. (2) After dissolving the above amide carboxylic acid structure product in an organic solvent, add the corresponding metal hydroxide to carry out a semi-solid reaction. The reaction is carried out at room temperature for 8 to 24 hours. After the reaction is completed, remove the organic solvent by vacuum distillation to obtain the aliphatic amide carboxylic acid product, i.e. Formula II.

3. The method for preparing the β-nucleating agent according to claim 2, characterized in that, In step (1), the molar ratio of tetrahydrophthalic anhydride to 1,4-cyclohexanediamine is (2.1-2.5):

1.

4. The method for preparing the β-nucleating agent according to claim 2, characterized in that, In step (2), the metal hydroxide is at least one of calcium hydroxide, magnesium hydroxide, lanthanum hydroxide, zinc hydroxide, and barium hydroxide.

5. The method for preparing the β-nucleating agent according to claim 2, characterized in that, In step (2), the molar ratio of the amide carboxylic acid structure product to the metal hydroxide is 3:(2-3).

6. The method for preparing the β-nucleating agent according to claim 2, characterized in that, In step (1), when tetrahydrophthalic anhydride undergoes an amidation reaction with 1,4-cyclohexanediamine, the organic solvent is at least one of chloroform, tetrahydrofuran, methanol, acetone, benzene, and toluene.

7. The method for preparing the β-nucleating agent according to claim 2, characterized in that, In step (2), when the amide carboxylic acid product reacts with the metal hydroxide in a semi-solid reaction, the organic solvent is at least one of methanol, dimethyl sulfoxide, n-hexane, and benzene.

8. The method for preparing the β-nucleating agent according to claim 2, characterized in that, In step (1), the reaction of tetrahydrophthalic anhydride and 1,4-cyclohexanediamine is carried out at room temperature for 12 to 24 hours.

9. The application of the β-nucleating agent according to claim 1 in polypropylene materials.

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