Modified polypropylene-based composite material as well as preparation method and application thereof
By preparing modified polypropylene-based composite materials, the problem of insufficient performance of plastic pipes in Panax notoginseng planting pillars was solved, and high-performance, low-cost support pillars were used to replace wooden pillars, which are suitable for planting supports for crops such as Panax notoginseng.
Patent Information
- Application Number
- CN202510757979.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-09
- Publication Date
- 2025-09-16
AI Technical Summary
When existing plastic pipes are used as planting supports for shade-loving crops such as Panax notoginseng, they have insufficient tensile, bending, compressive and impact resistance, poor aging resistance, and high cost, and cannot replace wooden pillars for long-term use.
Modified polypropylene-based composite materials are prepared by adding modified inorganic fillers, toughening agents, lubricants and antioxidants using a twin-screw extruder and hot pressing-cold pressing process to improve their mechanical properties.
Modified polypropylene-based composite materials have excellent mechanical properties, can be used for a long time, are low-cost, environmentally friendly, and reduce resource waste. They are suitable for supporting the planting of crops such as Panax notoginseng.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical application field of modified polypropylene plastic pipes, and specifically relates to a modified polypropylene-based composite material and a preparation method and application thereof. Background Art
[0002] At present, the pillars of shade sheds and sunshade nets used for growing shade-loving crops such as Panax notoginseng are made of fir, miscellaneous wood or bamboo. However, wooden pillars are relatively expensive and their supporting performance will be greatly affected when they are in outdoor environments for a long time. In addition, the use of a large number of wooden pillars will also cause a certain amount of resource waste. Replacing the above-mentioned wooden pillars with plastic pipes can achieve the goal of reducing wood consumption and realizing the long-term recycling of pillars. However, there are currently no specific practical cases of using plastic pipes as pillars. When replacing existing wooden pillars, there will be insufficient performance, including tensile strength, bending strength, compression strength, impact resistance, and aging resistance, as well as high manufacturing costs. In actual use, it is necessary to design the structure of the polypropylene support pipe so that it can fix the sunshade net while not being pulled up by the influence of severe weather such as strong winds, affecting agricultural operations. Summary of the Invention
[0003] In response to the shortcomings of the existing technology, the present invention provides a modified polypropylene-based composite material with excellent mechanical properties and a preparation method thereof. The mechanical strength of the modified polypropylene composite material is comparable to that of wooden pillars, and it can be used as a support pillar for planting crops such as Panax notoginseng and can be used for a long time under outdoor conditions.
[0004] The present invention is achieved through the following technical solutions: A modified polypropylene-based composite material is prepared from the following components in parts by weight: 59-84.6 parts of polypropylene, 10-25 parts of modified inorganic filler, 5-20 parts of toughening agent, 0.1-0.5 parts of lubricant, 0.05-0.5 parts of light stabilizer, and 0.01-0.3 parts of antioxidant.
[0005] The polypropylene is a low melt index polypropylene, and its melt index is less than 4g / 10min under standard testing.
[0006] The modified inorganic filler is surface-treated with a silane coupling agent to enhance its interaction with the polypropylene matrix. The specific preparation method is as follows: the silane coupling agent is added to ethanol, stirred and mixed, and then sprayed on the surface of the inorganic filler. After drying in an oven, the modified inorganic filler can be obtained; the inorganic filler is calcium carbonate, glass fiber, etc., the silane coupling agent is γ-aminopropyltriethoxysilane, the mass ratio of the silane coupling agent to the inorganic filler is 1:200-1:400, the drying temperature is 60-80°C, and the time is 12 hours.
[0007] The toughening agent is ethylene-octene copolymer (POE) elastomer.
[0008] The lubricant is a stearic acid lubricant.
[0009] The light stabilizer is an anti-ultraviolet aging agent (2,6-di-tert-butyl-p-methylphenol).
[0010] The antioxidant is a hindered phenol antioxidant.
[0011] The present invention also provides a method for preparing the modified polypropylene-based composite material, comprising the following steps: Polypropylene, modified inorganic filler, toughening agent, lubricant, light stabilizer and antioxidant are weighed according to the proportion, mixed evenly to obtain a mixture, added into a twin-screw extruder, melt-blended and extruded to obtain particles, and then hot-pressed and cold-pressed to obtain a modified polypropylene-based composite material.
[0012] The temperature of the extruder is 160-200° C., and the speed of the extruder is 30-150 rpm.
[0013] The hot pressing-cold pressing is performed at a pressure of 10-15 MPa and 160-200° C. for 150-500 seconds, and then at a pressure of 5-10 MPa for 60-120 seconds.
[0014] The present invention also provides the application of the modified polypropylene-based composite material in the planting of crops such as Panax notoginseng. The modified polypropylene composite material can be used to manufacture pillar products for awnings, especially for preparing pillar supports for Panax notoginseng planting, which can replace wooden pillars and can be recycled.
[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The modified polypropylene-based composite material of the present invention can be recycled and has lower cost: Compared with wooden pillars, polypropylene pillars can be recycled repeatedly during their service life, and the overall use cost is lower.
[0016] (2) The crop pillars made of the modified polypropylene-based composite material of the present invention are more environmentally friendly and can be recycled repeatedly. They can also reduce the problems of pests and diseases that may be caused by traditional wooden pillars, and are beneficial to the growth of crops such as Panax notoginseng.
[0017] (3) The toughness, impact resistance and strength of the modified polypropylene-based composite material of the present invention are adjustable, and its performance can be optimized and regulated compared to traditional wooden columns.
[0018] (4) The production process of the modified polypropylene-based composite material of the present invention is simple, and the process of preparing it into crop pillars is simple, without the need for new pipe molds and equipment. It has lower cost, good tensile and bending resistance and aging resistance, and is worthy of promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 The SEM cross-sectional photographs of the composite materials, wherein (a) Example 3; (b) Example 1; (c) Example 2; (d) Comparative Example 1; Figure 2 This is a structural diagram of the Panax notoginseng pillar. DETAILED DESCRIPTION
[0020] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. The following embodiments are intended to further illustrate the present invention rather than to limit the scope of the present invention.
[0021] The polypropylene used in the embodiment of the present invention is a low melt index polypropylene, and its melt index is less than 4.0 g / 10 min.
[0022] Example 1
[0023] A method for preparing a modified polypropylene plastic composite material comprises the following steps: (1) After 10 mL of γ-aminopropyltriethoxysilane (KH550) and 200 mL of anhydrous ethanol were mixed evenly, the mixture was sprayed on the surface of 5 g of calcium carbonate inorganic filler and dried in an oven at 60 °C for 12 h to obtain a modified inorganic filler; (2) 75 parts by weight of polypropylene, 20 parts by weight of ethylene-octene copolymer (POE) elastomer, 5 parts by weight of the modified inorganic filler treated above, 0.5 parts by weight of magnesium stearate lubricant, 0.05 parts by weight of UV aging agent (2,6-di-tert-butyl-p-methylphenol), and 0.02 parts by weight of hindered phenol antioxidant 1010 were mixed and uniformly obtained to obtain a mixture; (3) The mixed material was added to a twin-screw extruder (LSHJ-20, Shanghai Kechuang Rubber & Plastic Machinery Equipment Co., Ltd.), the extrusion temperature was set to 175°C (from the feeding section to the die section), the feed rate was set to 1.5 rpm, and the screw speed was set to 50 rpm. The moisture content of the material during extrusion by the twin-screw extruder was less than 0.5 wt%. After cooling, the material was placed in a pelletizer and cut into pellets. (4) The pellets were dried at 60 °C for 8 h to reduce the moisture content of the material to less than 0.5 wt%, and then placed in a flat vulcanizer, hot pressed at a pressure of 10 MPa and 180 °C for 300 s, and then cold pressed at a pressure of 5 MPa for 60 s to form a polypropylene-based composite material.
[0024] Example 2
[0025] A method for preparing a modified polypropylene plastic composite material comprises the following steps: (1) After 10 mL of γ-aminopropyltriethoxysilane (KH550) and 200 mL of anhydrous ethanol were mixed evenly, the mixture was sprayed on the surface of 5 g of calcium carbonate inorganic filler and dried in an oven at 60 °C for 12 h to obtain a modified inorganic filler; (2) 65 parts of polypropylene, 20 parts of octene-polyolefin copolymer (POE) elastomer, 15 parts of the modified inorganic filler treated above, 0.5 parts of magnesium stearate lubricant, 0.05 parts of UV aging agent (2,6-di-tert-butyl-p-methylphenol), and 0.02 parts of hindered phenol antioxidant 1010 were mixed uniformly to obtain a mixture; (3) The mixed material was added to a twin-screw extruder (LSHJ-20, Shanghai Kechuang Rubber & Plastic Machinery Equipment Co., Ltd.), the extrusion temperature was set to 175°C (from the feeding section to the die section), the feed rate was set to 1.5 rpm, and the screw speed was set to 50 rpm. The moisture content of the material during extrusion by the twin-screw extruder was less than 0.5 wt%. After cooling, the material was placed in a pelletizer and cut into pellets. (4) The pellets were dried at 60 °C for 8 h to reduce the moisture content of the material to less than 0.5 wt%, and then placed in a flat vulcanizer, hot pressed at a pressure of 10 MPa and 180 °C for 300 s, and then cold pressed at a pressure of 5 MPa for 60 s to form a polypropylene-based composite material.
[0026] Example 3
[0027] A method for preparing a modified polypropylene plastic composite material comprises the following steps: (1) After 10 mL of γ-aminopropyltriethoxysilane (KH550) and 200 mL of anhydrous ethanol were mixed evenly, the mixture was sprayed on the surface of 5 g of glass fiber inorganic filler and dried in an oven at 60 °C for 12 h to obtain a modified inorganic filler; (2) 65 parts of polypropylene, 20 parts of octene-polyolefin copolymer (POE) elastomer, 15 parts of the modified inorganic filler treated above, 0.5 parts of magnesium stearate lubricant, 0.05 parts of UV aging agent (2,6-di-tert-butyl-p-methylphenol), and 0.02 parts of hindered phenol antioxidant 1010 were mixed uniformly to obtain a mixture; (3) The mixed material was added to a twin-screw extruder (LSHJ-20, Shanghai Kechuang Rubber & Plastic Machinery Equipment Co., Ltd.), the extrusion temperature was set to 175°C (from the feeding section to the die section), the feed rate was set to 1.5 rpm, and the screw speed was set to 50 rpm. The moisture content of the material during extrusion by the twin-screw extruder was less than 0.5 wt%. After cooling, the material was placed in a pelletizer and cut into pellets. (4) The pellets were dried at 60 °C for 8 h to reduce the moisture content of the material to less than 0.5 wt%, and then placed in a flat vulcanizer, hot pressed at a pressure of 10 MPa and 180 °C for 300 s, and then cold pressed at a pressure of 5 MPa for 60 s to form a polypropylene-based composite material.
[0028] Example 4
[0029] A method for preparing a modified polypropylene plastic composite material comprises the following steps: (1) After 10 mL of γ-aminopropyltriethoxysilane (KH550) and 200 mL of anhydrous ethanol were mixed evenly, the mixture was sprayed on the surface of 5 g of glass fiber inorganic filler and dried in an oven at 60 °C for 12 h to obtain a modified inorganic filler; (2) 70 parts by weight of polypropylene, 15 parts of octene-polyolefin copolymer (POE) elastomer, 15 parts of the modified inorganic filler treated above, 0.5 parts of magnesium stearate lubricant, 0.05 parts of UV aging agent (2,6-di-tert-butyl-p-methylphenol), and 0.02 parts of hindered phenol antioxidant 1010 were mixed uniformly to obtain a mixture; (3) The mixed material was added to a twin-screw extruder (LSHJ-20, Shanghai Kechuang Rubber & Plastic Machinery Equipment Co., Ltd.), the extrusion temperature was set to 175°C (from the feeding section to the die section), the feed rate was set to 1.5 rpm, and the screw speed was set to 50 rpm. The moisture content of the material during extrusion by the twin-screw extruder was less than 0.5 wt%. After cooling, the material was placed in a pelletizer and cut into pellets. (4) The pellets were dried at 60 °C for 8 h to reduce the moisture content of the material to less than 0.5 wt%, and then placed in a flat vulcanizer, hot pressed at a pressure of 10 MPa and 180 °C for 300 s, and then cold pressed at a pressure of 5 MPa for 60 s to form a polypropylene-based composite material.
[0030] Example 5
[0031] A method for preparing a modified polypropylene plastic composite material comprises the following steps: (1) After 10 mL of γ-aminopropyltriethoxysilane (KH550) and 200 mL of anhydrous ethanol were mixed evenly, the mixture was sprayed on the surface of 8 g of glass fiber inorganic filler and dried in an oven at 80 °C for 12 h to obtain a modified inorganic filler; (2) 65 parts of polypropylene, 15 parts of octene-polyolefin copolymer (POE) elastomer, 20 parts of the modified inorganic filler treated above, 0.3 parts of magnesium stearate lubricant, 0.5 parts of UV aging agent (2,6-di-tert-butyl-p-methylphenol), and 0.3 parts of hindered phenol antioxidant 1010 were mixed uniformly to obtain a mixture; (3) The mixed material was added to a twin-screw extruder (LSHJ-20, Shanghai Kechuang Rubber & Plastic Machinery Equipment Co., Ltd.), the extrusion temperature was set to 200 °C (from the feeding section to the die section), the feed rate was set to 1.5 rpm, and the screw speed was set to 150 rpm. The moisture content of the material during extrusion by the twin-screw extruder was less than 0.5 wt%. After cooling, the material was placed in a pelletizer and cut into pellets. (4) The pellets were dried at 60 °C for 8 h to reduce the moisture content of the material to less than 0.5 wt%, and then placed in a flat vulcanizer, hot pressed at a pressure of 12 MPa and 160 °C for 500 s, and then cold pressed at a pressure of 10 MPa for 70 s to form a polypropylene-based composite material.
[0032] Example 6
[0033] A method for preparing a modified polypropylene plastic composite material comprises the following steps: (1) After 10 mL of γ-aminopropyltriethoxysilane (KH550) and 200 mL of anhydrous ethanol were mixed evenly, the mixture was sprayed on the surface of 2 g of glass fiber inorganic filler and dried in an oven at 70 °C for 12 h to obtain a modified inorganic filler; (2) 84.6 parts of polypropylene, 10 parts of octene-polyolefin copolymer (POE) elastomer, 10 parts of the modified inorganic filler treated above, 0.1 parts of magnesium stearate lubricant, 0.1 parts of UV aging agent (2,6-di-tert-butyl-p-methylphenol), and 0.01 parts of hindered phenol antioxidant 1010 were mixed uniformly to obtain a mixture; (3) The mixed material was added to a twin-screw extruder (LSHJ-20, Shanghai Kechuang Rubber & Plastic Machinery Equipment Co., Ltd.), the extrusion temperature was set to 160°C (from the feeding section to the die section), the feed rate was set to 1.5 rpm, and the screw speed was set to 30 rpm. The moisture content of the material during extrusion by the twin-screw extruder was less than 0.5 wt%. After cooling, the material was placed in a pelletizer and cut into pellets. (4) The pellets were dried at 60 °C for 8 h to reduce the moisture content of the material to less than 0.5 wt%, and then placed in a flat vulcanizer, hot pressed at a pressure of 15 MPa and 200 °C for 150 s, and then cold pressed at a pressure of 6 MPa for 120 s to form a polypropylene-based composite material.
[0034] Comparative Example 1 Pure polypropylene was added to a twin-screw extruder (LSHJ-20, Shanghai Kechuang Rubber & Plastic Machinery Co., Ltd.) with an extrusion temperature of 175°C (from the feed section to the die section), a feed rate of 1.5 rpm, and a screw speed of 50 rpm. The moisture content of the material during extrusion was less than 0.5 wt%. After cooling, the material was placed in a pelletizer and cut into pellets. The pellets were dried at 60°C for 8 hours to reduce the moisture content of the material to less than 0.5wt%, and then placed in a flat vulcanizer, hot-pressed at a pressure of 10MPa and 180°C for 300s, and then cold-pressed at a pressure of 5MPa for 60s to form polypropylene material.
[0035] Comparative Example 2 80 parts of polypropylene and 20 parts of polypropylene elastomer (EPM) were added to a twin-screw extruder (LSHJ-20, Shanghai Kechuang Rubber and Plastic Machinery Equipment Co., Ltd.). The extrusion temperature was set to 175°C (from the feeding section to the die section), the feed rate was set to 1.5 rpm, and the screw speed was set to 50 rpm. The moisture content of the material during extrusion was less than 0.5 wt%. After cooling, the material was placed in a pelletizer and cut into pellets. The particles were dried at 60°C for 8 hours to reduce the moisture content of the material to less than 0.5wt%, and then placed in a flat vulcanizer, hot-pressed at a pressure of 10MPa and 180°C for 300s, and then cold-pressed at a pressure of 5MPa for 60s to form a polypropylene-based composite material.
[0036] Comparative Example 3 80 parts of polypropylene and 20 parts of octene-polyolefin copolymer (POE) elastomer were added to a twin-screw extruder (LSHJ-20, Shanghai Kechuang Rubber and Plastic Machinery Equipment Co., Ltd.). The extrusion temperature was set to 175°C (from the feeding section to the die section), the feed rate was set to 1.5 rpm, and the screw speed was set to 50 rpm. The moisture content of the material during extrusion was less than 0.5 wt%. After cooling, the material was placed in a pelletizer and cut into pellets. The particles were dried at 60°C for 8 hours to reduce the moisture content of the material to less than 0.5wt%, and then placed in a flat vulcanizer, hot-pressed at a pressure of 10MPa and 180°C for 300s, and then cold-pressed at a pressure of 5MPa for 60s to form a polypropylene-based composite material.
[0037] The effects of different elastomers on the mechanical properties of polypropylene composites are shown in Table 1. It can be seen that although the EPM group has improved impact strength at break and tensile modulus compared with POE, the tensile strength and elongation at break are much lower than those of the POE group, indicating that the addition of POE improves toughness much more than that of EPM. Therefore, POE is selected as a toughening agent in the examples.
[0038] Table 1 Comparison of mechanical properties of different elastomer-modified polypropylene composites
[0039] Table 2 Mechanical properties of modified polypropylene composites
[0040] By combining toughening agents and rigid inorganic fillers, a balance of strength and toughness of the material can be achieved. By comparing calcium carbonate (Example 2) and glass fiber (Example 3) with the same addition amount, it can be found that the addition of both inorganic fillers can improve the rigidity of the material, and its bending / tensile modulus is further enhanced, and the difference is not large. However, compared with calcium carbonate, glass fiber has less effect on the toughness of the composite material. Compared with calcium carbonate composite materials, polypropylene composite materials with glass fiber added have higher segment impact strength and fracture impact energy. The flexural strength of the 65 parts polypropylene / 20 parts POE / 15 parts modified calcium carbonate composite material in Example 2 is 23.68 MPa, and the flexural modulus is 818.82 MPa, while The elongation at break is 51.61%. Replacing calcium carbonate with 15 parts of modified glass fiber can further increase the elongation at break to 76.13% (Example 3). Further changing the POE content found that the mechanical properties of 70 parts of polypropylene / 15 parts of POE / 15 parts of modified glass fiber in Example 4 reached the optimal value, with a flexural strength of 23.79 MPa, a flexural modulus of 896.57 MPa, and an elongation at break of 102.51%. Compared with unmodified polypropylene, its flexural strength, flexural modulus, and elongation at break increased significantly. After further increasing the glass fiber content to 20 parts (Example 5), although the tensile modulus increased, the elongation at break decreased significantly.
[0041] Table 3 Melt flow index of PP and its composite materials
[0042] From the changes in the melt index in Table 3, it can be seen that the addition of toughening agent and inorganic filler glass fiber will increase the melt index of polypropylene to a certain extent, but the melt index of all modified composite materials is below 2.5g / 10min, which meets the processing requirements of pipe extrusion.
[0043] from Figure 1 The cross-sectional SEM analysis of (a) Example 3; (b) Example 1; (c) Example 2; (d) Comparative Example 1 shows that the composite material with glass fiber added produced more voids under impact, indicating that when the material was subjected to external impact, the glass fiber and the elastomer POE particles jointly played a role in delaying the development of cracks. The POE particles absorbed the impact energy by deformation, and the glass fiber absorbed the impact energy by pulling out and breaking. This proves why the glass fiber group is stronger than the calcium carbonate group in mechanical properties.
[0044] Example 7
[0045] The modified polypropylene plastic composite material obtained in Example 4 was used to prepare a pillar for planting Panax notoginseng. Figure 2The figure includes a tube body 1, a fixed base 2, and a fixed line 3. The tube body 1 is 2m long, the outer tube diameter is 12cm, the inner tube diameter is 10cm, and the top of the tube is provided with an external thread about 15cm long for fixing the awning. A fixed base 2 is provided 20cm away from the bottom end of the tube. The fixed base 2 is a hollow cylindrical disk with an inner diameter of 12cm, which can fit with the tube body 1 and be stuck at the bottom position of the tube body 1. The fixed base 2 has 4 circular holes to connect the fixing line 3 to stabilize the tube support.
[0046] The particles prepared in step (2) of Example 4 are used, and according to the structure of the pillar for planting Panax notoginseng, a tube body 1, a fixed base 2, and a fixed line 3 are respectively prepared using a mold according to step (3) of Example, and then assembled to obtain a pillar for planting Panax notoginseng. The pillar is set next to Panax notoginseng, and the top of the tube body 1 has an external thread for fixing the sunshade. After completion, it is observed that Panax notoginseng grows normally and is not easy to fall over. After the planting and harvest of Panax notoginseng, the pillar is removed and stored for use when planting Panax notoginseng again.
[0047] The specific embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.
Claims
1. A modified polypropylene-based composite material, characterized in that: The invention comprises the following components in parts by weight: 59-84.6 parts of polypropylene, 10-25 parts of modified inorganic filler, 5-20 parts of toughening agent, 0.1-0.5 parts of lubricant, 0.05-0.5 parts of light stabilizer and 0.01-0.3 parts of antioxidant.
2. The modified polypropylene-based composite material according to claim 1, characterized in that: The polypropylene is a low melt index polypropylene with a melt index of less than 4.0 g / 10 min.
3. The modified polypropylene-based composite material according to claim 1, characterized in that: The preparation method of the modified inorganic filler is as follows: adding a silane coupling agent to ethanol, stirring and mixing, spraying the mixture on the surface of the inorganic filler, and drying the mixture to obtain the modified inorganic filler; the inorganic filler is calcium carbonate or glass fiber, the silane coupling agent is γ-aminopropyltriethoxysilane, the mass ratio of the silane coupling agent to the inorganic filler is 1:200-1:400, the drying temperature is 60-80°C, and the drying time is 12 hours.
4. The modified polypropylene-based composite material according to claim 1, characterized in that: The toughening agent is an ethylene-octene copolymer elastomer.
5. The modified polypropylene-based composite material according to claim 1, characterized in that: The lubricant is a stearic acid lubricant.
6. The modified polypropylene-based composite material according to claim 1, characterized in that: The light stabilizer is an anti-ultraviolet aging agent (2,6-di-tert-butyl-p-methylphenol).
7. The modified polypropylene-based composite material according to claim 1, characterized in that: The antioxidant is a hindered phenol antioxidant.
8. The method for preparing the modified polypropylene-based composite material according to claim 1, characterized in that: Polypropylene, modified inorganic filler, toughening agent, lubricant, light stabilizer and antioxidant are weighed according to a proportion, mixed evenly to obtain a mixture, added into a twin-screw extruder, melt-blended and extruded to obtain particles, and hot-pressed and cold-pressed to obtain a modified polypropylene-based composite material.
9. The method for preparing the modified polypropylene-based composite material according to claim 8, characterized in that: The extruder temperature is 160-200° C., and the extruder speed is 30-150 rpm; the hot pressing-cold pressing is performed at a pressure of 10-15 MPa and 160-200° C. for 150-500 seconds, and then at a pressure of 5-10 MPa for 60-120 seconds.
10. The modified polypropylene-based composite material according to claim 1 is used as a support for crop planting.