A polypropylene composition, its preparation method and application

Abstract

This invention discloses a polypropylene composition, its preparation method, and its applications, belonging to the field of polymer material modification technology. The polypropylene composition comprises a matrix polypropylene, a second polypropylene, a polyolefin elastomer, a masterbatch A composed of bismaleimide monomers, a third polypropylene, zirconium phosphate, and a silane coupling agent, masterbatch B. This invention achieves excellent interfacial compatibilization and controllable crosslinking within the polyolefin elastomer phase through the reaction of maleic anhydride and dodecyl diamine with bismaleimide monomers. Simultaneously, ball-milled modified zirconium phosphate provides efficient heterogeneous nucleation, significantly improving the crystallinity of the matrix. The resulting polypropylene composition better balances rigidity and toughness, broadening the application prospects of polypropylene materials in high-performance fields.

Description

Technical Field

[0001] This application belongs to the field of polymer material modification technology, and in particular relates to a polypropylene composition, its preparation method and application. Background Technology

[0002] Polypropylene (PP), as a general-purpose plastic, possesses excellent comprehensive properties, but its inherent low-temperature brittleness and insufficient rigidity limit its application in some fields with high mechanical performance requirements. PP is typically toughened using polyolefin elastomers (POE), but the addition of POE significantly reduces the material's crystallinity and rigidity, leading to a contradiction of "toughening without rigidity."

[0003] To overcome this contradiction, various methods have been employed in existing technologies. For example, preparing PP / POE masterbatches using reactive monomers or crosslinking agents is one approach. However, some crosslinking agents (such as short-chain bismaleimide) have poor compatibility with the polyolefin matrix, easily leading to uneven dispersion and powder-to-particle separation during premixing and processing, thus limiting their reaction efficiency and performance improvement in the final composition. Furthermore, relying solely on elastomer toughening is insufficient to significantly improve matrix rigidity.

[0004] On the other hand, adding rigid inorganic fillers (such as zirconium phosphate) is a direct way to improve the rigidity of materials, but the uniform dispersion and good interfacial bonding of the filler in the polymer matrix are technical challenges. If the filler is poorly dispersed, it is prone to agglomeration, which not only affects its nucleation effect but may also become stress concentration points, leading to a decrease in the toughness of the material.

[0005] Therefore, developing a polypropylene composition that can balance rigidity and toughness has significant research and application value. Summary of the Invention

[0006] To address the technical problem of balancing rigidity and toughness in existing polypropylene compositions, the primary objective of this invention is to provide a polypropylene composition.

[0007] Another object of the present invention is to provide a method for preparing the above-described polypropylene composition.

[0008] Another object of the present invention is to provide the application of the above-mentioned polypropylene composition in the preparation of automotive parts and power tool parts.

[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: This invention protects a polypropylene composition comprising the following components in parts by weight: 100 parts of polypropylene matrix; In addition to the 100 parts of the base polypropylene, the composition also includes 10-60 parts of the second polypropylene; 20-33 parts of the polyolefin elastomer; 0.5-3 parts of the bismaleimide monomer, forming masterbatch A; and 5-15 parts of the third polypropylene; 0.5-3 parts of zirconium phosphate; and 0.1-5 parts of the silane coupling agent, forming masterbatch B. The bismaleamic acid monomer is obtained by reacting maleic anhydride with 1,12-dodecyldiamine. The preparation method of the masterbatch B is to ball-mill polypropylene powder, zirconium phosphate and silane coupling agent until the characteristic diffraction peaks of the original zirconium phosphate crystal plane disappear in the XRD pattern of the masterbatch B, and a diffraction peak appears at 2θ=4.53°.

[0010] This invention addresses the traditional challenge of significantly reduced rigidity in the toughening modification of polypropylene. It innovatively employs long-chain C12-bismaleamic acid (C12-BMA) as a reactive compatibilizer, combined with a ball-milled silane coupling agent intercalation / pre-dispersed zirconium phosphate nucleating masterbatch, to construct a synergistic system. C12-BMA, with its excellent compatibility, achieves efficient compatibilization at the PP-POE interface during processing, inducing the formation of an ultrafine, uniform elastomer dispersion phase, providing a foundation for high toughness. Simultaneously, ball-milled zirconium phosphate, as a highly efficient heterogeneous nucleating agent, significantly improves the crystallinity of the PP matrix, thereby significantly enhancing rigidity. The combination of these two components through stepwise masterbatch preparation ultimately produces a significant synergistic effect in the composite material, achieving a balanced unity of high rigidity, high toughness, and high crystallinity.

[0011] Masterbatch B was prepared by ball milling. When the characteristic diffraction peaks of the original zirconium phosphate crystal plane disappeared in the XRD pattern and a diffraction peak appeared at 2θ=4.53°, the ball milling treatment achieved the effect of zirconium phosphate intercalated silane coupling agent.

[0012] Preferably, the preparation method of the bismaleimide monomer refers to the prior art, specifically as follows: A relative excess of maleic anhydride and 1,12-dodecyl diamine were dissolved separately in chloroform. The diamine solution was slowly added dropwise to the anhydride solution under stirring at room temperature. After reacting at room temperature for 4 hours, the mixture was filtered, washed with chloroform, and dried under vacuum at 40°C to obtain the bismaleimide monomer C12-BMA.

[0013] Preferably, the polyolefin elastomer has a mass content of 15-20 wt% in the polypropylene composition.

[0014] Preferably, both the matrix polypropylene and the second polypropylene are in granular form.

[0015] Preferably, the melt index of the matrix polypropylene is 2.0~8.0 g / 10min at 230℃ / 2.16kg.

[0016] Preferably, the melt index of the second polypropylene is 2.0~8.0 g / 10min at 230℃ / 2.16kg.

[0017] Preferably, the third polypropylene is in powder form. Powdered polypropylene is more conducive to uniform mixing during the ball milling process. The powder with better rigidity can avoid adhering to the tank wall during the ball milling process, which helps the mechanical action and intercalation effect of zirconium phosphate and silane coupling agent, and improves the processing effect.

[0018] Preferably, the melt index of the third polypropylene is 10~15 g / 10min at 230℃ / 2.16kg.

[0019] Preferably, the molar ratio of maleic anhydride to 1,12-dodecyldiamine is 1~2.5:1.

[0020] Preferably, the zirconium phosphate has a lateral dimension of 1~3μm and a sheet diameter and thickness of 50~100nm.

[0021] The lateral dimension is the maximum length along any direction on the plane of the zirconium phosphate sheet.

[0022] Preferably, the ball milling conditions are: ball milling speed of 300~700 rpm and ball milling time of 20~50 min.

[0023] A method for preparing the above-mentioned polypropylene composition includes the following steps: S1. Preparation of Masterbatch A: Melt extrusion granulation of second polypropylene, polyolefin elastomer, bismaleimide monomer and initiator; S2. Preparation of Masterbatch B: The third polypropylene, zirconium phosphate and silane coupling agent are ball-milled to obtain composite masterbatch B; S3. Melt extrusion granulation of masterbatch A, masterbatch B and matrix polypropylene.

[0024] Preferably, the initiator in step S1 is a peroxide initiator, and its mass fraction is 0.1 to 0.3% of the mass of masterbatch A.

[0025] Preferably, the silane coupling agent in step S2 is selected from at least one of γ-aminopropyltriethoxysilane, γ-aminopropyldimethoxyethoxysilane, or N-β-(aminopropyl)ethylenediaminomethylpropyltrimethoxysilane.

[0026] Preferably, the masterbatch A in step S1 is prepared by melt blending, with a blending temperature of 180~200℃, a rotation speed of 50~70 rpm, and a blending time of 8~12 minutes.

[0027] The application of the above-mentioned polypropylene composition in the preparation of automotive and home appliance parts and piping systems is also within the scope of protection of this invention.

[0028] Compared with the prior art, the present invention has the following beneficial effects: The polypropylene composition provided by this invention achieves excellent interfacial compatibilization and controllable crosslinking within the polyolefin elastomer phase by bismaleimide monomers obtained through the reaction of maleic anhydride and dodecyl diamine. At the same time, ball-milled modified zirconium phosphate provides efficient heterogeneous nucleation, significantly improving the crystallinity of the matrix. The resulting polypropylene composition better balances rigidity and toughness. Attached Figure Description

[0029] Figure 1 Photographs showing the adsorption and dispersion of C12-BMA (Example 1) and C6-BMA (Comparative Example 1) on the surface of PP / POE mixed particles.

[0030] Figure 2 This is a comparison of the torque-time curves of masterbatch A (using C12-BMA) and comparative masterbatch (using C6-BMA) during the melt blending process.

[0031] Figure 3 This is a comparison XRD pattern of masterbatch B, polypropylene matrix, and original zirconium phosphate in Example 1 of the present invention.

[0032] Figure 4 The image shows a comparison of the XRD patterns of masterbatch B, polypropylene matrix, and raw zirconium phosphate in Comparative Example 6 of this invention. Detailed Implementation

[0033] The present invention is further illustrated below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions in the art or as recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from the conventional market. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention are within the scope of protection claimed by the present invention.

[0034] I. The reagents used in the various embodiments and comparative examples of this invention are described below: Matrix polypropylene 1#: Yangzi Petrochemical PPH-T03-S, melt index 3.5 g / 10min at 230℃ / 2.16 kg.

[0035] Second polypropylene 1#: Yangzi Petrochemical PPH-T03-S, melt index 3.5 g / 10min at 230℃ / 2.16 kg.

[0036] Second polypropylene #2: Maoming Petrochemical PPH-M06, with a melt index of 6 g / 10 min at 230℃ / 2.16 kg.

[0037] Third polypropylene 1#: Z30S powder from Ningxia Baofeng Energy Group Co., Ltd., with a melt index of 20 g / 10 min at 230℃ / 2.16 kg.

[0038] The third polypropylene #2: Maohua Shihua PP-150 powder, with a melt index of 12g / 10min at 230℃ / 2.16kg.

[0039] Polyolefin elastomer: POE, Dow Chemical Engage 8150.

[0040] C12-BMA: Relatively excess maleic anhydride and 1,12-dodecyl diamine were dissolved separately in chloroform. The diamine solution was slowly added dropwise to the anhydride solution under stirring at room temperature. After reacting at room temperature for 4 hours, the mixture was filtered, washed with chloroform, and dried under vacuum at 40°C to obtain C12-BMA.

[0041] C6-BMA: The preparation method is the same as that of C12-BMA, except that 1,12-dodecyldiamine is replaced with an equimolar amount of hexamethylenediamine to obtain C6-BMA.

[0042] C10-BMA: The preparation method is the same as that of C12-BMA, except that 1,12-dodecyldiamine is replaced with an equimolar amount of 1,10-decanediamine to obtain C10-BMA.

[0043] C14-BMA: The preparation method is the same as that of C12-BMA, except that 1,12-dodecyldiamine is replaced with an equimolar amount of 1,14-tetradecyldiamine to obtain C14-BMA.

[0044] Initiator: Dicumyl peroxide (DCP), commercially available.

[0045] Zirconium phosphate (ZrP): Sichuan Mianzhu Yaolong Chemical Co., Ltd.

[0046] Silane coupling agent: γ-aminopropyltriethoxysilane KH550, commercially available.

[0047] II. Test Indicators (1) Flexural modulus: tested according to GB / T 9341-2008 standard.

[0048] (2) Elongation at break: Tested according to GB / T 1040-2006 standard, with a tensile rate of 50 mm / min.

[0049] (3) Notched impact strength: Tested according to GB / T 1843-2008 standard, type A notch.

[0050] (4) Crystallinity: Determined by differential scanning calorimetry (DSC) and calculated based on enthalpy of fusion.

[0051] III. Experimental Methods Preparation method: S1. Preparation of Masterbatch A: Polypropylene, polyolefin elastomer, bismaleimide monomer and 0.3 parts by weight of peroxide initiator (DCP) are melt-blended in an internal mixer at 190°C and 60 rpm for 10 minutes, and then discharged and granulated. S2. Preparation of Masterbatch B: Polypropylene powder, layered zirconium phosphate, and silane coupling agent (KH550) are added to a ball mill at 500 rpm for 30 minutes to obtain composite masterbatch B. At this point, if... Figure 3 As shown, the characteristic diffraction peaks of the original zirconium phosphate crystal plane disappear in the XRD pattern of masterbatch B, at 2 θ A diffraction peak appears at 4.53°. S3. The masterbatch A obtained in step S1 and the masterbatch B obtained in step S2 are melt-blended with the matrix polypropylene in a twin-screw extruder. The screw speed of the twin-screw extruder is 80 r / min, and the temperature of each section is set as follows: 185℃, 195℃, 210℃, 190℃, 180℃.

[0052] Table 1 Components of Examples 1-9

[0053] Example 10 The preparation method is the same as in Example 1, except that the ball milling time for preparing masterbatch B is 20 min. At this time, the characteristic diffraction peaks of the original zirconium phosphate crystal plane disappear in the XRD pattern of masterbatch B. θ A diffraction peak appears at 4.53°.

[0054] Example 11 The preparation method is the same as in Example 1, except that the ball milling time for preparing masterbatch B is 50 min. At this time, the characteristic diffraction peaks of the zirconium phosphate crystal plane disappear in the XRD pattern of masterbatch B. θ A diffraction peak appears at 4.53°.

[0055] Comparative Example 1 The components and methods are the same as in Example 1, except that C6-BMA is used instead of C12-BMA.

[0056] Comparative Example 2 The components and methods are the same as in Example 1, except that C10-BMA is used instead of C12-BMA.

[0057] Comparative Example 3 The components and methods are the same as in Example 1, except that C14-BMA is used instead of C12-BMA.

[0058] Comparative Example 4 The components and methods are the same as in Example 1, except that zirconium phosphate is not added.

[0059] Comparative Example 5 The components are the same as in Example 1, the only difference being the preparation method: The same mass fractions of polypropylene, polyolefin elastomer, bismaleimide monomer, and 0.3 parts by mass of peroxide initiator (DCP), polypropylene powder, layered zirconium phosphate milled for 30 min, and silane coupling agent (KH550) were simultaneously melt-blended with the matrix polypropylene in a twin-screw extruder. The screw speed of the twin-screw extruder was 80 r / min, and the temperatures of each section were set as follows: 185°C, 195°C, 210°C, 190°C, and 180°C.

[0060] Comparative Example 6 The composition and method are the same as in Example 1, except that the ball milling treatment was insufficient when preparing masterbatch B, with a ball milling time of only 10 min. The XRD pattern of masterbatch B is shown below. Figure 4 The characteristic diffraction peaks of the zirconium phosphate crystal plane still exist in 2. θ No diffraction peaks were observed at 4.53°.

[0061] IV. Performance Test Results Table 2 Test Results of Examples and Comparative Examples

[0062] As can be seen from Examples 1 and 2, in polypropylene systems with different melt indices, the composite system using C12-BMA in this invention exhibits significantly better impact strength and flexural modulus than the comparative examples, indicating that this technical solution has good matrix adaptability. Furthermore, polypropylene with higher crystallinity possesses higher strength and stiffness while maintaining good toughness, making it an excellent polypropylene material.

[0063] As can be seen from Examples 5 and 6, although the flexural modulus, elongation at break, and impact strength of the material fluctuate to some extent when the PP / POE ratio in masterbatch A changes, the overall performance remains at a high level. This indicates that C12-BMA can achieve effective interface control under different pre-dispersion structure conditions, enabling the elastomer phase to form a stable phase structure with the polypropylene matrix, demonstrating good interfacial compatibility and structural stability. This also shows that C12-BMA can react effectively under different PP / POE ratios, demonstrating its wide adaptability.

[0064] Compared to Example 1, the amount of zirconium phosphate in Example 7 was reduced to 0.8 parts. The flexural modulus (1280 MPa), impact strength (35.2 kJ / m²), and crystallinity (43.5%) were slightly lower than in Example 1, but still remained at a high level. This indicates that a good balance of rigidity and toughness can still be achieved by appropriately reducing the amount of zirconium phosphate, demonstrating the wide adaptability of the formulation.

[0065] Compared to Example 1, Example 8 increased the zirconium phosphate content to 2.3 parts. The flexural modulus (1480 MPa) and crystallinity (46.2%) were significantly improved, but the elongation at break (520%) and impact strength (22.3 kJ / m²) decreased significantly. This indicates that excessive zirconium phosphate sacrifices some toughness, but the overall performance is still superior to Comparative Examples 4 and 5, validating the preferred range of zirconium phosphate.

[0066] As can be seen from Examples 10-11, as the ball milling time increased from 20 min to 50 min, the flexural modulus and crystallinity of the material further improved, while the elongation at break and impact strength decreased slightly. This indicates that the degree of filler dispersion and lamellar exfoliation have a significant impact on the microstructure of the material. A moderate ball milling time is beneficial for improving the nucleation efficiency and interfacial bonding strength of lamellar α-zirconium phosphate, but excessive strengthening of interfacial constraints may restrict the movement of matrix chain segments, thereby reducing toughness.

[0067] Comparative Examples 1, 2, and 3 used C6-BMA, C10-BMA, and C14-BMA to replace C12-BMA in Example 1, respectively. The results showed that both excessively short (C6) and excessively long (C14) chain lengths were detrimental to interfacial compatibility and dispersion: C6-BMA had poor compatibility with the polypropylene matrix, was prone to aggregation during processing, leading to uneven elastomer dispersion and a significant decrease in impact strength and flexural modulus; while C14-BMA showed improved compatibility, its reactivity was reduced, its crosslinking degree was insufficient, and its impact strength and crystallinity were significantly inferior to the C12-BMA system. This indicates that the C12 chain length achieves an optimal balance between compatibility and reactivity.

[0068] Comparative Example 4 did not add zirconium phosphate, relying solely on the elastomer toughening system in masterbatch A. Compared to Example 1, although the elongation at break was still higher, the flexural modulus and crystallinity were significantly reduced, indicating that the matrix rigidity could not be effectively improved without the heterogeneous nucleation effect of zirconium phosphate, thus confirming the key role of zirconium phosphate in achieving a balance between rigidity and toughness.

[0069] Comparative Example 5 employed a one-time blending method. Before the C12-BMA underwent a crosslinking reaction with the polyolefin macromolecules, it preferentially reacted with the amino groups on the surface of the KH550 modified zirconium phosphate through an acid-base neutralization reaction. A large number of active sites were anchored on the filler surface, preventing uniform diffusion to the POE / PP interface and the elastomer phase, resulting in insufficient crosslinking network construction. Simultaneously, the interfacial compatibility between the filler and the matrix was not effectively improved, limiting the heterogeneous nucleation of zirconium phosphate. Compared to Example 1, the crystallinity of Comparative Example 5 decreased from 45.5% to 38.2%, the flexural modulus decreased from 1350 MPa to 1150 MPa, the notched impact strength decreased significantly from 38.1 kJ / m² to 15.5 kJ / m², and the elongation at break decreased from 820% to 450%. This clearly demonstrates that a step-by-step process (preparing masterbatch A and masterbatch B separately, then mixing them) is crucial to ensuring that each component performs its function and achieving a balance between rigidity and toughness.

[0070] When preparing masterbatch B in Comparative Example 6, ball milling was performed for 10 minutes. Figure 4 As shown, the characteristic diffraction peaks of the original zirconium phosphate crystal plane are still present in the XRD pattern of masterbatch B. No diffraction peak appears at 2θ=4.53°, indicating that insufficient ball milling treatment cannot induce the intercalation effect of silane coupling agent and zirconium phosphate.

[0071] Figure 1 These are dispersion photographs of C12-BMA and C6-BMA during the premixing stage of processing. It can be seen that the light yellow C6-BMA powder is mostly concentrated at the bottom of the bottle, while the white C12-BMA powder is very scarce at the bottom, instead being uniformly adsorbed on the particle surface.

[0072] Figure 2 This is a comparison of the torque-time curves of masterbatch A (using C12-BMA) and the comparative masterbatch (using C6-BMA) during the melt blending process. It can be seen that both exhibit crosslinking reaction peaks in addition to the feeding peak, but the C12-BMA system shows more pronounced and uniform crosslinking.

[0073] Figure 3 The XRD patterns of masterbatch B, polypropylene matrix, and original zirconium phosphate are shown in the figure. The XRD pattern of masterbatch B retains all characteristic diffraction peaks of polypropylene, while the characteristic diffraction peak (11.46°) of the original zirconium phosphate (002) crystal plane almost completely disappears, and a new diffraction peak appears at 2θ = 4.53° (marked with a star in the figure). According to the Bragg equation, the interlayer spacing increases to 1.91 nm, indicating that KH550 achieved intercalation of zirconium phosphate during ball milling.

[0074] Figure 4 No diffraction peaks were observed at 2θ = 4.53°, and characteristic diffraction peaks of the original zirconium phosphate crystal plane appeared at the marked location in the figure.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polypropylene composition, characterized in that, The components included in the following mass fraction calculations are: 100 parts of polypropylene matrix; In addition to the 100 parts of the base polypropylene, the composition also includes 10-60 parts of the second polypropylene; 20-33 parts of the polyolefin elastomer; 0.5-3 parts of the bismaleimide monomer, forming masterbatch A; and 5-15 parts of the third polypropylene; 0.5-3 parts of zirconium phosphate; and 0.1-5 parts of the silane coupling agent, forming masterbatch B. The bismaleamic acid monomer is obtained by reacting maleic anhydride with 1,12-dodecyldiamine. The preparation method of the masterbatch B is to ball-mill polypropylene powder, zirconium phosphate, and silane coupling agent until the characteristic diffraction peaks of the original zirconium phosphate crystal plane disappear in the XRD pattern of the masterbatch B. θ A diffraction peak appears at 4.53°.

2. The polypropylene composition according to claim 1, characterized in that The melt index of the second polypropylene in the masterbatch A is 2.0~8.0 g / 10min at 230℃ / 2.16kg.

3. The polypropylene composition according to claim 1, characterized in that The melt flow index of the third polypropylene powder in the masterbatch B is 10~15 g / 10min at 230℃ / 2.16kg.

4. The polypropylene composition according to claim 1, characterized in that The molar ratio of maleic anhydride to 1,12-dodecyldiamine is 1~2.5:

1.

5. The polypropylene composition according to claim 1, characterized in that The conditions for ball milling are: ball milling speed 300~700 rpm, ball milling time 20~50 min.

6. A process for the preparation of the polypropylene composition according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Preparation of Masterbatch A: Melt extrusion granulation of second polypropylene, polyolefin elastomer, bismaleimide monomer and initiator; S2. Preparation of Masterbatch B: The third polypropylene, zirconium phosphate and silane coupling agent are ball-milled to obtain composite masterbatch B; S3. Melt extrusion granulation of masterbatch A, masterbatch B and matrix polypropylene.

7. The preparation method according to claim 6, characterized in that, The initiator mentioned in step S1 is a peroxide initiator, with a mass fraction of 0.1 to 0.3% of the mass of masterbatch A.

8. The preparation method according to claim 6, characterized in that, The silane coupling agent in step S2 is selected from at least one of γ-aminopropyltriethoxysilane, γ-aminopropyldimethoxyethoxysilane, or N-β-(aminopropyl)ethylenediaminomethylpropyltrimethoxysilane.

9. The preparation method according to claim 6, characterized in that, The masterbatch A mentioned in step S1 is prepared by melt blending at a temperature of 180~200℃, a speed of 50~70 rpm, and a time of 8~12 minutes.

10. The use of the polypropylene composition according to any one of claims 1 to 5 in the preparation of automotive and home appliance parts and piping systems.

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