Additives with both compatibility and nucleation properties, their preparation methods and applications

Abstract

This invention discloses an additive possessing both compatibility and nucleation properties, its preparation method, and its application. The preparation method of the additive is as follows: Polypropylene grafted with maleic anhydride is dissolved in xylene, and then methyl 3-amino-4-methoxybenzoate is added for reaction. After precipitation, filtration, and drying, the additive possessing both compatibility and nucleation properties is obtained. In the additive of this invention, the benzene ring of the N-substituted phenyl compound / 4-{[2-methoxy-5-(methoxycarbonyl)phenyl]amino}-4-oxobutyric acid serves as a crystal growth surface, inducing epitaxial crystallization of PP chains, promoting PP nucleation, and improving the heat resistance of PP resin. The carboxyl group of 4-{[2-methoxy-5-(methoxycarbonyl)phenyl]amino}-4-oxobutyric acid undergoes an esterification reaction with the hydroxyl group on the surface of CaCO3, improving the hydrophobicity of CaCO3 and enhancing the compatibility of PP / CaCO3. This additive with compatibility and nucleation properties can improve the mechanical properties of PP / CaCO3.

Description

Technical Field

[0001] This invention relates to the field of PP modification technology, and in particular to additives, preparation methods and applications that combine compatibility and nucleation properties. Background Technology

[0002] Polypropylene (PP) is one of the lightest plastics available, boasting excellent molding properties, glossy surfaces, and superior heat and corrosion resistance. It is widely used in injection molding, extrusion, woven fabrics, films, high-impact copolymers, thin-wall injection molding, fibers, and thermoformed products. PP products have a broad range of downstream applications. Due to its low density, good chemical resistance, and high melting temperature, it is one of the most widely used plastics in microwave food containers. Even so, PP still has drawbacks such as poor impact resistance and toughness, typically requiring modification with inorganic fillers to enhance its mechanical properties. Furthermore, calcium carbonate (CaCO3) is widely used in PP modification due to its low cost, high whiteness, and wide availability. However, the rich hydrophilic groups on the surface of CaCO3, such as hydroxyl and carboxyl groups, lead to its tendency to agglomerate and poor compatibility with the PP resin matrix, reducing the mechanical properties of the composite material. Therefore, surface modification treatment of CaCO3 is necessary.

[0003] To improve the compatibility of PP and CaCO3, current methods involve hydrophobic modification of CaCO3 or compatibilization modification of the PP / CaCO3 system by adding compatibilizers. For example, the two-step enhancement effect of compatibilizers and nucleating agents has solved the problems of poor compatibility and easy agglomeration between PP and CaCO3. However, the preparation process of modifying CaCO3 and compatibilizers separately, preparing nucleation masterbatches, and finally melt extrusion granulation is complex and not conducive to large-scale industrial production. Similarly, when the amount of CaCO3 added is small, adding compatibilizers can improve the interfacial compatibility between PP and CaCO3, thus improving the mechanical properties of the composite material. However, as the amount of CaCO3 added increases, the interfacial interaction between PP and CaCO3 also strengthens, and the compatibilization effect of compatibilizers alone still results in poor CaCO3 dispersion and poor mechanical properties of the composite material. Summary of the Invention

[0004] Based on the problems existing in the background technology, this invention proposes an additive, preparation method and application that have both compatibility and nucleation properties, which can overcome the problem of poor compatibility between PP and CaCO3, effectively improve the crystallinity of PP, and improve the mechanical properties and heat resistance of PP.

[0005] The present invention proposes a method for preparing an additive with both compatibility and nucleation properties, the method steps of which are as follows: polypropylene grafted with maleic anhydride is dissolved in xylene, and then methyl 3-amino-4-methoxybenzoate is added to react. After precipitation, filtration and drying, the additive with both compatibility and nucleation properties is obtained.

[0006] Preferably, the molar ratio of polypropylene grafted with maleic anhydride to methyl 3-amino-4-methoxybenzoate is 1:1-1.2.

[0007] Preferably, the reaction temperature is 115-135℃ and the reaction time is 3-5h.

[0008] The additive prepared by the above method proposed in this invention has both compatibility and nucleation properties.

[0009] The present invention relates to the application of the above-mentioned additives with both compatibility and nucleation properties in modified PP materials.

[0010] Preferably, the method steps are as follows: PP, CaCO3 and additives are mixed at high speed and then melt-extruded.

[0011] Preferably, the mass ratio of PP, CaCO3 and additives is 5:1:0.025-0.075.

[0012] Preferably, the melt extrusion conditions are: screw speed of 200-300 rpm, feeding speed of 5-7 Hz, and extrusion temperature range of 165, 170, 170, 175, 180, 185, 190, 190, 190, 185, 180℃.

[0013] Beneficial technical effects of the present invention:

[0014] (1) In this invention, maleic anhydride grafted onto polypropylene undergoes a substitution reaction with methyl 3-amino-4-methoxybenzoate, resulting in the one-step synthesis of an N-substituted phenyl compound with both nucleating properties and compatible 4-{[2-methoxy-5-(methoxycarbonyl)phenyl]amino}-4-oxobutyric acid. This invention utilizes a one-step synthesis process for the substitution reaction, which is simple and avoids lengthy separation and purification processes in post-processing.

[0015] (2) In the N-substituted phenyl compound / 4-{[2-methoxy-5-(methoxycarbonyl)phenyl]amino}-4-oxobutyric acid of the present invention, the benzene ring on the N-substituted phenyl compound serves as a crystal growth surface, inducing epitaxial crystallization of PP chains, promoting PP nucleation, and improving the crystallinity and heat resistance of PP resin; the carboxyl group of 4-{[2-methoxy-5-(methoxycarbonyl)phenyl]amino}-4-oxobutyric acid undergoes esterification with the hydroxyl group on the surface of CaCO3, improving the hydrophobicity of CaCO3 and enhancing the interfacial compatibility of PP / CaCO3. The additive with compatibility and nucleation properties improves the mechanical properties of PP / CaCO3. Attached Figure Description

[0016] Figure 1 This is a comparison FTIR image of PP-g-MAH and the auxiliary agent N-SPC / MMCPAOA proposed in this invention;

[0017] Figure 2 Comparison of crystallization / melting curves for PP, PP / CaCO3, and PP / CaCO3 / additive N-SPC / MMCPAOA proposed in this invention; where (a) is the cooling crystallization process and (b) is the heating melting process.

[0018] Figure 3 This is a schematic diagram of the synthesis mechanism of the auxiliary agent N-SPC / MMCPAOA proposed in this invention;

[0019] Figure 4 This is a schematic diagram of the compatibility mechanism of the additive N-SPC / MMCPAOA proposed in this invention in the PP / CaCO3 system. Detailed Implementation

[0020] The present invention will be further explained below with reference to specific embodiments.

[0021] Example 1

[0022] The method for preparing modified PP materials proposed in this scheme has the following steps:

[0023] S1: Weigh 20g of polypropylene grafted with maleic anhydride (PP-g-MAH, purchased from Huangshan Beno Technology Co., Ltd.) and add it to 100mL of xylene; then, heat to 115℃ until completely dissolved; then, weigh 1g of methyl 3-amino-4-methoxybenzoate (AMBME) and add it to the above solution, react at 115℃ for 4h to obtain the product solution.

[0024] S2: Pour the above solution into a beaker containing 110 mL of methanol and stir continuously with a glass rod to precipitate the product; then, filter the suspension to obtain the preproduct. Place the preproduct in an oven at 80 °C and dry for 4 h to obtain the auxiliary agent N-substituted phenyl compound (N-SPC) / 4-{[2-methoxy-5-(methoxycarbonyl)phenyl]amino}-4-oxobutyric acid (MMCPAOA).

[0025] S3: Weigh 1 kg PP, 0.2 kg CaCO3 and 10 g of the above-mentioned additive N-SPC / MMCPAOA, and mix them at high speed to obtain a mixture.

[0026] S4: Melt and extrude the mixture described in S3. The screw speed is 200 rpm, the feeding speed is 5 Hz, and the extrusion temperature range is set to 160, 165, 170, 175, 180, 185, 190, 190, 190, 185, 180℃.

[0027] Example 2

[0028] The method for preparing modified PP materials proposed in this scheme has the following steps:

[0029] S1: Weigh 25g of PP-g-MAH and add it to 100mL of xylene; then, heat to 115℃ until completely dissolved; then, weigh 1g of AMBME and add it to the above solution, and react at 115℃ for 4h to obtain the product solution.

[0030] S2: Pour the above solution into a beaker containing 110 mL of methanol and stir continuously with a glass rod to precipitate the product; then, filter the suspension to obtain the preproduct. Place the preproduct in an oven at 80 °C and dry for 4 h to obtain the auxiliary agent N-SPC / MMCPAOA.

[0031] S3: Weigh 1 kg PP, 0.2 kg CaCO3 and 10 g of the above-mentioned additive N-SPC / MMCPAOA, and mix them at high speed to obtain a mixture.

[0032] S4: Melt and extrude the mixture described in S3. The screw speed is 200 rpm, the feeding speed is 5 Hz, and the extrusion temperature range is set to 160, 165, 170, 175, 180, 185, 190, 190, 190, 185, 180℃.

[0033] Example 3

[0034] The method for preparing modified PP materials proposed in this scheme has the following steps:

[0035] S1: Weigh 20g of PP-g-MAH and add it to 100mL of xylene; then, heat to 135℃ until completely dissolved; then, weigh 1g of AMBME and add it to the above solution, and react at 135℃ for 4h to obtain the product solution.

[0036] S2: Pour the above solution into a beaker containing 110 mL of methanol and stir continuously with a glass rod to precipitate the product; then, filter the suspension to obtain the preproduct. Place the preproduct in an oven at 80 °C and dry for 4 h to obtain the auxiliary agent N-SPC / MMCPAOA.

[0037] S3: Weigh 1 kg PP, 0.2 kg CaCO3 and 10 g of the above-mentioned additive N-SPC / MMCPAOA, and mix them at high speed to obtain a mixture.

[0038] S4: Melt and extrude the mixture described in S3. The screw speed is 200 rpm, the feeding speed is 5 Hz, and the extrusion temperature range is set to 160, 165, 170, 175, 180, 185, 190, 190, 190, 185, 180℃.

[0039] Comparative Example 1

[0040] The method for preparing modified PP materials proposed in this scheme has the following steps:

[0041] S1: Weigh 1 kg PP, 0.2 kg CaCO3 and 10 g PP-g-MAH, and mix them at high speed to obtain a mixture.

[0042] S2: The mixture described in S1 is melt-extruded at a screw speed of 200 rpm and a feeding speed of 5 Hz. The extrusion temperature range is set to 160, 165, 170, 175, 180, 185, 190, 190, 190, 185, and 180℃.

[0043] The present invention performs infrared spectroscopy on the PP-g-MAH sample in Example 1 and the N-SPC / MMCPAOA additive, which also has compatibility and nucleation properties, and the results are as follows: Figure 1 As shown in the figure. It can be seen from the figure that, compared to PP-g-MAH, the auxiliary agent with both compatibility and nucleation properties has a higher efficiency at 1700 cm⁻¹. -1 There is an absorption peak at 1617 and 1595 cm⁻¹, which is attributed to the stretching vibration peak induced by C=O; -1 The two rabbit-ear-shaped absorption peaks are absorption peaks of the skeletal vibration of orthophthalene. This indicates that PP-g-MAH and AMBME undergo a substitution reaction to produce N-SPC with a benzene ring and MMCPAOA with a carboxyl group.

[0044] Differential calorimetry (DCS) tests were performed on PP samples, Comparative Example 1 samples, and Sample 1 of Example 1. The results are as follows: Figure 2 As shown in the figure, (a) represents the cooling crystallization process and (b) represents the heating melting process; the thermodynamic parameters of the samples are detailed in Table 1.

[0045] Table 1 Thermodynamic parameters of the samples

[0046]

[0047] Depend on Figure 2 As shown in (a) and Table 1, the crystallization temperature of the PP / CaCO3 / N-SPC / MMCPAOA sample prepared in Example 1 increased, reaching a maximum of 135.93℃, with the crystallization peak approaching the high-temperature region and the crystallization enthalpy also increasing accordingly. During the cooling process, the additive N-SPC / MMCPAOA can provide crystal nuclei at higher temperatures and induce PP molecular chains to attach and grow on them, acting as a nucleating agent. The increased crystallinity of the PP / CaCO3 composite material after adding the additive N-SPC / MMCPAOA indicates that the additive N-SPC / MMCPAOA can promote the crystallization of the PP / CaCO3 composite material.

[0048] Depend on Figure 2 (b) and Table 1 show that the melting temperature of the PP / CaCO3 / additive N-SPC / MMCPAOA sample prepared in Example 1 increased to a maximum of 169.22℃, and the melting peak area increased, indicating that the additive N-SPC / MMCPAOA can effectively improve the thermal properties of PP materials.

[0049] Figure 3 This is a schematic diagram of the synthesis mechanism of the auxiliary agent N-SPC / MMCPAOA proposed in this invention. Figure 3 (a) is a schematic diagram of the structure of PP-g-MAH. Figure 3 (b) is a structural diagram of AMBME. Figure 3 (c) is a schematic diagram of the synthesis mechanism of the auxiliary agent N-SPC / MMCPAOA. First, the primary amine of AMBME attacks the anhydride group of PP-g-MAH, opening the ring to form the derivative MMCPAOA. Second, the aromatic framework of AMBME has electron-withdrawing groups, which is conducive to the formation of amide N anions. The generated amide N anions react with the carbonyl group of the free carboxyl group to close the ring and generate N-SPC. The benzene ring on N-SPC serves as the growth surface of the crystal, inducing the epitaxial crystallization of PP chains, promoting PP nucleation, and improving the heat resistance of PP resin.

[0050] Figure 4 This is a schematic diagram illustrating the compatibility mechanism of the additive N-SPC / MMCPAOA proposed in this invention in the PP / CaCO3 system. From... Figure 4It can be seen that during the melt blending process of PP / CaCO3 / additive N-SPC / MMCPAOA, the carboxyl groups on MMCPAAOA undergo esterification with the abundant hydroxyl groups on the surface of CaCO3, thereby making the surface of CaCO3 hydrophobic. MMCPAAOA can improve the compatibility between CaCO3 and PP resin and enhance the mechanical properties of the product.

[0051] The mechanical properties of PP samples, Comparative Example 1 samples, and Example 1 samples were tested in this invention, and the results are shown in Table 2. As can be seen from the table, the PP / CaCO3 / N-SPC / MMCPAOA sample prepared in Example 1 achieved a maximum tensile strength of 32.22 MPa and a maximum elongation at break of 669%. When PP is directly blended with CaCO3, stress concentration and cracking occur during the tensile process due to the poor interfacial compatibility between PP and CaCO3, resulting in a significant decrease in the mechanical properties of the material. However, the mechanical properties of the material are significantly improved after adding the compatibility nucleating agent N-SPC / MMCPAOA, which enhances the compatibility between PP and CaCO3. Furthermore, the N-SPC / MMCPAOA also acts as a nucleating agent, improving the crystallinity of PP, shrinking the polymer volume, increasing intermolecular attraction, and thus improving mechanical properties.

[0052] Table 2. Mechanical property testing of samples

[0053]

Claims

1. A method for preparing an auxiliary agent possessing both compatibility and nucleation properties, characterized in that, The method steps are as follows: Polypropylene grafted with maleic anhydride is dissolved in xylene, and then methyl 3-amino-4-methoxybenzoate is added to react. After precipitation, filtration and drying, an auxiliary agent with both compatibility and nucleation properties is obtained.

2. The method for preparing the auxiliary agent with both compatibility and nucleation properties according to claim 1, characterized in that, The molar ratio of polypropylene grafted with maleic anhydride to methyl 3-amino-4-methoxybenzoate is 1:1-1.

2.

3. The method for preparing the auxiliary agent with both compatibility and nucleation properties according to claim 1, characterized in that, The reaction temperature is 115-135℃, and the reaction time is 3-5 hours.

4. An additive with both compatibility and nucleation properties prepared by the method according to any one of claims 1-3.

5. The application of the additive with both compatibility and nucleation properties as described in claim 4 in modified PP materials.

6. The application of the additive with both compatibility and nucleation properties according to claim 5 in modified PP materials, characterized in that, The method and steps are as follows: PP, CaCO3 and additives are mixed at high speed and then melt extruded.

7. The application of the additive with both compatibility and nucleation properties as described in claim 6 in modified PP materials, characterized in that, The mass ratio of PP, CaCO3 and additives is 5:1:0.025-0.

075.

8. The application of the additive with both compatibility and nucleation properties as described in claim 6 in modified PP materials, characterized in that, The conditions for melt extrusion are: screw speed of 200-300 rpm, feed rate of 5-7 Hz, and extrusion temperature range of 165, 170, 170, 175, 180, 185, 190, 190, 190, 185, 180℃.

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