Polypropylene composite material with high impact resistance and high fluidity and preparation method thereof

Abstract

The invention discloses a polypropylene composite material with high impact resistance and high fluidity and a preparation method thereof. The polypropylene composite material is prepared from the following components in parts by weight: 300 to 425 parts of polypropylene resin, 25 to 50 parts of a toughening agent, 50 to 150 parts of talcum powder, 1.5 parts of an antioxidant, 2.5 parts of a dispersing agent and 0.5 to 2 parts of an aluminate coupling agent. The talcum powder is modified by using the aluminate coupling agent, and the crosslinking density in an organic phase is enhanced, so that the mechanical property of the polypropylene composite material is improved, and the polypropylene composite material disclosed by the invention has high impact resistance and high flowability.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and particularly relates to a high-impact and high-fluidity polypropylene composite material and a preparation method thereof. Background Art

[0002] Talc is a hydrated magnesium silicate mineral with a lamellar structure. It possesses high electrical insulation, excellent heat resistance, general insensitivity to strong acids and alkalis, strong oil absorption and hiding power, and excellent lubricity and machinability. my country is relatively abundant in talc resources. As a functional filler, talc can increase the heat distortion temperature of filled polypropylene (PP), reduce molding shrinkage, and enhance material rigidity. The addition of ultrafine talc can also improve PP's impact resistance and impart excellent surface properties. Talc-filled PP composites, due to their lightweight, low-cost, easy processing, mature modified products, recyclability, and excellent overall performance, have gained widespread recognition in the automotive and home appliance industries, with their application growing annually. Numerous domestic and international companies and research institutes have conducted research on this topic and achieved significant results.

[0003] Currently, talc-filled polypropylene on the market is typically filled directly to reduce costs, improve mechanical properties, thermal stability, and enhance the dimensional stability of the finished product. However, PP's macromolecular chains are non-polar, resulting in poor compatibility with inorganic fillers, making it prone to phase separation or delamination, which can lead to a decrease in the material's impact resistance. Therefore, talc modification is often used to address this issue.

[0004] Existing talc modification technologies mostly use silane coupling agents, titanate coupling agents or homemade surfactants for surface treatment. Wang Duo et al. used the self-developed surfactant R(C2H4O)nSO4Na to treat talc powder (Wang Duo, Lei Zeyichuan, Zhou Jing. Research on surface modifiers for PP-filled talc powder [J]. Applied Chemical Industry, 2024, 53(01): 131-132.); Ding Yunsheng et al. used silane coupling agent to modify talc powder (Ding Yunsheng, Geng Hongwei, Wang Sengshan. Effect of crystallinity and phase morphology of talc powder / polypropylene composite materials on their mechanical properties [J]. Polymer Materials Science and Engineering, 2005, (05): 90-93.); Li Qingjiang used phosphate coupling agent to treat the surface of talc powder to improve the dispersibility of talc powder and its affinity with polypropylene (Li Qingjiang. Effect of phosphate coupling agent (FX-1) on the properties of PP / POE / Talc composite materials [J]. Plastics, 2014, 43(01): 33-35+10.). However, these modification methods are costly and have strict production conditions. The modified talc powder is prone to performance degradation in high temperature or high humidity environments, and there is still room for improvement in impact resistance and fluidity. Summary of the Invention

[0005] To solve the above problems, the present invention provides a polypropylene composite material with high impact resistance and high fluidity and a preparation method thereof. The surface of talcum powder is modified by using an aluminate coupling agent, which effectively increases the bonding force between the resin and the talcum powder and improves various properties of the composite material. The prepared polypropylene composite material has high impact resistance and high fluidity.

[0006] To achieve the above-mentioned object, the technical solution of the present invention is: a high-impact and high-flow polypropylene composite material, wherein the components and proportions of the polypropylene composite material are as follows: 300-425 parts of polypropylene resin, 25-50 parts of toughening agent, 50-150 parts of talc, 1.5 parts of antioxidant, 2.5 parts of dispersant, and 0.5-2 parts of aluminate coupling agent.

[0007] Preferably, the components and proportions of the polypropylene composite material are: 375 parts of polypropylene resin, 25 parts of toughening agent, 100 parts of talc, 1.5 parts of antioxidant, 2.5 parts of dispersant, and 1.5-2 parts of aluminate coupling agent.

[0008] Preferably, the polypropylene resin is homopolypropylene or copolymer polypropylene, or a mixture of the two. The melt flow rate of the homopolypropylene or copolymer polypropylene is 10-30 g / 10 min (230° C., 2.16 kg).

[0009] Preferably, the toughening agent is one of ethylene-octene copolymer (POE), ethylene-propylene rubber (EPR), and styrene-butadiene-styrene block copolymer (SBS).

[0010] Preferably, the talc powder has a particle size of 2.5-5.5 μm and a silicon content of 55-60.

[0011] Preferably, the antioxidant is one of antioxidant 1010, antioxidant 1076, and antioxidant 168, or a mixture of two of them.

[0012] Preferably, the dispersant is one of EBS and PE wax.

[0013] Preferably, the aluminate coupling agent is one of the aluminate coupling agents DL-411, DL-411AF, DL-411D, and DL-411DF.

[0014] The present invention also discloses a method for preparing the high-impact and high-fluidity polypropylene composite material, comprising the following steps:

[0015] Step 1: Raw material pretreatment: weigh polypropylene, toughening agent, antioxidant and dispersant according to the proportion;

[0016] Step 2: talc powder modification pretreatment: talc powder and aluminate coupling agent are weighed in proportion and added into a high-speed mixer, the mixing temperature is set to 90-100°C, the speed is 800-1200 r / min, and after mixing for 10-30 minutes, the mixed powder is cooled to room temperature to obtain modified talc powder;

[0017] Step 3: Mixing: Add the pretreated raw materials and modified talc into a high-speed mixer and mix at a speed of 800-1200 r / min for 3-5 minutes to ensure that all components are fully mixed;

[0018] Step 4, melt blending: add the mixed materials in step 3 into a twin-screw extruder for melt blending. The temperature of the twin-screw extruder is set as follows: zone 1 180-190°C, zone 2 190-200°C, zone 3 200-210°C, zone 4 210-220°C, die head 190-210°C, main engine frequency 35-45, and feeding frequency 10-15;

[0019] Step 5, extrusion granulation: the material after melt blending is extruded from the head of a twin-screw extruder, and is water-cooled, stretched, and pelletized to obtain composite polypropylene material particles.

[0020] Wherein, if the toughening agent is POE, it needs to be dried.

[0021] The talc powder in step 2 is dried at 100-120° C. for 3-5 hours to remove moisture before being modified.

[0022] For polypropylene composite materials, improving their impact resistance can enhance the durability of the material and reduce the damage caused by external impact, which is particularly important for applications (such as automobile bumpers) that need to withstand frequent collisions or external impacts. And good fluidity makes polypropylene composite materials uniform and easy to be processed into various shapes and sizes during processing such as injection molding and extrusion, with short molding cycle and high production efficiency. Therefore, in order to improve the performance of polypropylene composite materials in related fields, the present invention is mainly directed to the study of aluminate coupling agent modified talcum powder, and systematically studies the impact of its impact resistance and flow properties on talcum powder-filled PP composite materials.

[0023] The present invention adopts aluminate-modified talc powder. The aluminate coupling agent has the characteristics of high surface reactivity with inorganic fillers, light color, non-toxicity, high thermal decomposition temperature, etc., and is very suitable for large-scale production of modified talc powder.

[0024] The coupling agent of the present invention uses an aluminate coupling agent, which is added to a talc powder at a ratio of 0.5-2 wt%. The mixture is added to a high-speed mixer at 90-120°C, stirred at 800-1200 rpm for 10-30 minutes, and then rapidly cooled. Through the synergistic effects of temperature, shear force, and the ratio, the aluminate coupling agent effectively coats the surface of the talc powder, forming a "molecular bridge" connecting the inorganic filler and the organic matrix.

[0025] The hydroxyl groups in the aluminate coupling agent undergo an esterification reaction with organic compounds containing carboxyl groups, forming ester bonds. These bonds can increase the crosslink density in the organic phase, thereby improving the mechanical properties of the composite material. The aluminum ions form coordination bonds between the organic and inorganic phases, further enhancing their binding force and compatibility, allowing for better interaction between the organic and inorganic phases, effectively improving the composite material's performance and imparting high impact resistance and fluidity to the polypropylene composite material of the present invention.

[0026] The high-impact, high-flowability polypropylene composite material of the present invention and its preparation method have the following advantages:

[0027] The interfacial properties of talc and the mechanical strength of composite materials are significantly improved, and the fluidity and impact resistance of the composite materials filled with modified talc are significantly improved.

[0028] The modification has high uniformity, stable product quality, light color, non-toxicity, low odor, wide application range, no need for diluent, easy to use and low price. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to specific examples, but the present invention is not limited to these embodiments.

[0030] Example 1:

[0031] 1. Preparation

[0032] The composition of the polypropylene composite material includes the following components in parts by weight: 375 parts of polypropylene resin, 25 parts of toughening agent, 100 parts of talc, 1.5 parts of antioxidant, 2.5 parts of dispersant, and 1.5 parts of aluminate coupling agent.

[0033] Preparation method: comprising the following steps:

[0034] Step 1: Raw material pretreatment: Weigh polypropylene, toughening agent, antioxidant and dispersant in proportion. If the toughening agent is POE, it needs to be dried;

[0035] Step 2: Talc modification pretreatment: First, dry the talc at 100°C for 3 hours to remove moisture; weigh the talc and aluminate coupling agent in proportion and add them to a high-speed mixer. Set the mixing temperature to 110°C and the speed to 1000 r / min. After mixing for 30 minutes, quickly cool the mixed powder to room temperature;

[0036] Step 3: Mixing: Add the modified talc pretreated in step 2 and the polypropylene, toughening agent, antioxidant and dispersant prepared in step 1 into a high-speed mixer and mix at a speed of 1200 r / min for 5 minutes to ensure that the components are fully mixed;

[0037] Step 4, melt blending: add the mixed materials in step 3 into a twin-screw extruder for melt blending. The temperature of the twin-screw extruder is set as follows: zone 1 190°C, zone 2 200°C, zone 3 210°C, zone 4 220°C, die head 210°C, main engine frequency 40, and feeding frequency 12;

[0038] Step 5, extrusion granulation: the material after melt blending is extruded from the head of a twin-screw extruder, and is subjected to water cooling, stranding, and pelletizing to obtain the polypropylene material particles.

[0039] The talc powder is selected to have an average particle size of 5 μm and a silicon content of more than 60%.

[0040] The aluminate coupling agent is aluminate coupling agent DL-411.

[0041] Performance Testing

[0042] Unmodified talc was filled into PP resin (copolymer PPEP548R as the main resin and copolymer PP1215C as the auxiliary resin) to prepare sample 1 with 20% talc filled PP. The modified talc prepared in Example 1 was filled into PP resin to prepare sample 2 with 20% modified talc filled PP. The performance of each sample was tested, and the results are shown in Table 1.

[0043] Table 1 Test data of various performances of samples

[0044]

[0045] Results show that compared to the unmodified talc-filled PP sample prepared using the method of the present invention, the suspended impact strength increased by 43.6% and the melt index increased by 52.7%. This indicates that the polypropylene composite material prepared using the method of the present invention significantly improves impact resistance and melt index, while exhibiting minimal decreases in tensile strength and flexural strength, essentially maintaining its original performance.

[0046] Example 2:

[0047] 1. Preparation

[0048] A high-impact, high-fluidity polypropylene composite material comprises the following components, measured by weight: 375 parts of polypropylene resin, 25 parts of a toughening agent, 100 parts of talc, 1.5 parts of an antioxidant, 2.5 parts of a dispersant, and 2 parts of an aluminate coupling agent.

[0049] The preparation of the modified talc-filled PP with high impact resistance and high fluidity comprises the following steps:

[0050] Step 1: Raw material pretreatment: Weigh polypropylene, toughening agent, talc, antioxidant and dispersant in proportion. If the toughening agent is POE, it needs to be dried; talc is dried at 100°C for 3 hours to remove moisture;

[0051] Step 2: Talc modification pretreatment: weigh the talc and coupling agent in a certain proportion and add them into a high-speed mixer. Set the mixing temperature to 110°C and the speed to 1000 r / min. After mixing for 30 minutes, quickly cool the mixed powder to room temperature.

[0052] Step 3: Mixing: Add the pretreated modified talc, polypropylene, toughening agent, antioxidant and dispersant into a high-speed mixer and mix at a speed of 1200 r / min for 5 minutes to ensure that all components are fully mixed;

[0053] Step 4, melt blending: add the mixed materials into a twin-screw extruder for melt blending. The temperature of the twin-screw extruder is set as follows: zone 1 190°C, zone 2 200°C, zone 3 210°C, zone 4 220°C, die head 210°C, main engine frequency 40, and feeding frequency 12;

[0054] Step 5, extrusion granulation: the material after melt blending is extruded from the head of a twin-screw extruder, and is water-cooled, stretched, and pelletized to obtain composite polypropylene material particles.

[0055] In this embodiment, the talc powder is selected from talc powder with an average particle size of 2.5 μm and a silicon content of more than 60%.

[0056] The aluminate coupling agent is aluminate coupling agent DL-411.

[0057] 2. Performance Testing

[0058] Unmodified talc was filled into PP resin (copolymer PPEP548R as the main resin and copolymer PP1215C as the auxiliary resin) to prepare sample 3 with 20% talc-filled PP. The modified talc prepared in Example 2 of the present invention was filled into PP resin to prepare sample 4 with 20% modified talc-filled PP. The performance of each sample was tested, and the results are shown in Table 2.

[0059] Table 2 Performance test data of the samples

[0060]

[0061] The results show that the performance of the modified talc-filled PP sample prepared by the method of the present invention is compared with that of the unmodified sample. The impact strength increases by 49.4%, and the melt index increases by 65.7%. It can be seen that the polypropylene composite material prepared by the present invention greatly improves the impact resistance and melt index properties.

[0062] The polypropylene composite material preparation method of the present invention improves the performance of the product and meets the manufacturer's demand for high-quality finished products. Comprehensive performance evaluation shows that the polypropylene composite material prepared by the preparation method has the characteristics of high impact resistance and high fluidity.

[0063] The present invention modifies talc with an aluminate coupling agent. The hydroxyl groups in the aluminate coupling agent undergo an esterification reaction with organic compounds containing carboxyl groups to form ester bonds. This increases the crosslinking density in the organic phase, thereby improving the mechanical properties of the composite material. Aluminum ions form coordination bonds between the organic and inorganic phases, further enhancing their bonding and compatibility, and promoting better interaction between the organic and inorganic phases, thereby effectively improving the performance of the polypropylene composite material.

[0064] The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the creative concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A high-impact and high-flow polypropylene composite material, characterized in that: The components and proportions of the polypropylene composite material are as follows by weight: 300-425 parts of polypropylene resin, 25-50 parts of toughening agent, 50-150 parts of talc, 1.5 parts of antioxidant, 2.5 parts of dispersant, and 0.5-2 parts of aluminate coupling agent.

2. The polypropylene composite material according to claim 1, characterized in that The polypropylene resin is one of homopolypropylene or copolymer polypropylene or a mixture of the two. The melt flow rate of the homopolypropylene or copolymer polypropylene is 10-30 g / 10 min (230° C., 2.16 kg).

3. The polypropylene composite material according to claim 1, characterized in that The toughening agent is one of ethylene-octene copolymer, ethylene-propylene rubber, and styrene-butadiene-styrene block copolymer.

4. The polypropylene composite material according to claim 1, characterized in that The talc powder has a particle size of 2.5-5.5 μm and a silicon content of 55-60.

5. The polypropylene composite material according to claim 1, characterized in that The antioxidant is one of antioxidant 1010, antioxidant 1076, and antioxidant 168, or a mixture of two of them.

6. The polypropylene composite material according to claim 1, characterized in that The dispersant is one of EBS and PE wax.

7. The polypropylene composite material according to claim 1, characterized in that The aluminate coupling agent is one of the aluminate coupling agents DL-411, DL-411AF, DL-411D, and DL-411DF.

8. The method for preparing a high-impact and high-flow polypropylene composite material according to claim 1, wherein: The following steps are involved: Step 1: Raw material pretreatment: weigh polypropylene, toughening agent, antioxidant and dispersant according to the proportion; Step 2: talc powder modification pretreatment: talc powder and aluminate coupling agent are weighed in proportion and added into a high-speed mixer, the mixing temperature is set to 90-100°C, the speed is 800-1200 r / min, and after mixing for 10-30 minutes, the mixed powder is cooled to room temperature to obtain modified talc powder; Step 3: Mixing: Add the pretreated raw materials and modified talc into a high-speed mixer and mix at a speed of 800-1200 r / min for 3-5 minutes to ensure that all components are fully mixed; Step 4, melt blending: add the mixed materials in step 3 into a twin-screw extruder for melt blending. The temperature of the twin-screw extruder is set as follows: zone 1 180-190°C, zone 2 190-200°C, zone 3 200-210°C, zone 4 210-220°C, die head 190-210°C, main engine frequency 35-45, and feeding frequency 10-15; Step 5, extrusion granulation: the material after melt blending is extruded from the head of a twin-screw extruder, and is water-cooled, stretched, and pelletized to obtain composite polypropylene material particles.

9. The method for preparing a high-impact and high-flow polypropylene composite material according to claim 8, wherein: The talc powder in step 2 is dried at 100-120° C. for 3-5 hours to remove moisture before being modified.

Images