Rigid and toughened polypropylene composite material and preparation method thereof

Abstract

The invention discloses a reinforced and toughened polypropylene composite material 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 and 2.5 parts of a dispersing agent. The talcum powder with the optimal particle size and the optimal silicon content range is selected to carry out filling modification on the polypropylene material PP, so that the rigidity and the toughness of the polypropylene composite material product are greatly enhanced.

Description

Technical Field

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

[0002] Polypropylene (PP) has become the second-largest thermoplastic in the global plastics industry due to its low cost, high density, easy processing, excellent mechanical properties, and good chemical and temperature resistance. PP is widely used in a variety of applications, including automotive, consumer electronics, packaging, and toys. However, PP's linear hydrocarbon structure results in rapid crystallization and low melt strength, making the preparation of PP plastics with customized structures and high strength a significant challenge. To this end, both academia and industry have made significant efforts. Numerous studies have shown that nanofillers (such as cellulose nanocrystals, talc, and fiber reinforcements) are effective fillers for improving PP strength.

[0003] Talc is a naturally occurring silicate mineral that is formed by a combination of mineralogy, chemical properties, and crystal morphology. The diversity and complexity of talc products are a notable characteristic of talc products. PP is the most important target for talc-filled modified plastics. Talc-filled modified PP can increase the heat distortion temperature, enhance dimensional stability, reduce molding shrinkage, and improve rigidity. The addition of ultrafine talc masterbatch as a reinforcing filler to PP not only significantly improves the rigidity, surface hardness, creep resistance, and electrical insulation properties of PP products, but also enhances impact strength and impact resistance, imparting excellent surface properties. Talc also acts as a melt flow promoter and acts as a synergist with certain flame retardants. When added in small amounts, talc acts as a nucleating agent, refining the grain size and enhancing the crystallinity of the PP, thereby improving various mechanical properties and enhancing its transparency. The application of talc-filled PP modified materials in automobile and home appliance parts is increasing year by year due to its light weight, low price, easy processing, mature modified products, recyclability and excellent comprehensive performance.

[0004] Dou Qiang et al. used a small amount of POE toughening and talcum powder filling to prepare a special material for bumpers of mid- and low-end cars and light vehicles with good comprehensive performance and low cost, which was successfully used in Isuzu series light vehicles (Dou Qiang, Development of special material for polypropylene automobile bumpers. Plastics, 2004, (33) 1: 16-19); Shen Xin et al.'s research showed that a blend of POE with a mass fraction of 20%, talcum powder with a mass fraction of 15%, and a PP graft compatibilizer can produce a special material for automobile bumpers with good toughness and rigidity (Shen Xin, Wang Wei. PP / POE / Talc powder is a special material for automobile bumpers. Plastics Industry, 2005 (33) 4: 61-62); Lin Mingde et al. used the principle of high-order structure design to study the surface modification of talc powder and its filling PP to prepare a super polyolefin (SOP) polymer with elastomer as the matrix and talc powder as the filler. The structure and performance were discussed, indicating that this material has better comprehensive performance than traditional rubber-toughened PP when used to produce automobile bumpers (Lin Mingde, Yu Qiang. Research status of PP / elastomer / talc powder composite materials. China Plastics, 2002 (16) 4: 6-10). Cheng Lizhen et al. (Cheng Lizhen, Research on PP Special Materials for Fukang Automobile Instrument Panels. Plastics Technology, 2003, 3:10-13) used homopolymer PP, copolymer PP, talc, toughening agent, etc. to obtain PP special materials for automobile instrument panels with relatively ideal comprehensive performance. Among them, a high-filled polypropylene composite alloy with 30 parts of talc: Koshita Akir et al. used a melt blend of copolymer PP, EPDM, etc. plus 20-25 parts of talc and hydroxy magnesium sulfate to obtain a PP blend with good low-temperature toughness, heat resistance, high hardness, high mechanical strength, good appearance, and good processing fluidity, which is used as PP special materials for automobile instrument panels.

[0005] Particle size, silicon content, etc. are the main parameters of talc performance, and their influence on the performance of PP after filling is particularly important. In the current literature, there are few reports on in-depth and systematic research on different talc-modified polypropylene. Summary of the Invention

[0006] The object of the present invention is to provide a polypropylene composite material with increased rigidity and toughness and a preparation method thereof. The prepared polypropylene composite material has higher rigidity and toughness.

[0007] To achieve the above-mentioned purpose, the technical solution of the present invention is: a polypropylene composite material with increased rigidity and toughness, wherein 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 powder, 1.5 parts of antioxidant, and 2.5 parts of dispersant.

[0008] 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, and 2.5 parts of dispersant.

[0009] 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).

[0010] Preferably, the toughening agent is one of ethylene-octene copolymer (POE), ethylene-propylene rubber (EPR), and styrene-butadiene-styrene block copolymer (SBS).

[0011] Preferably, the talc powder has a particle size of 2-18 μm and a silicon content of 55-60.

[0012] The antioxidant is one of antioxidant 1010, antioxidant 1076, and antioxidant 168, or a mixture of two of them.

[0013] Preferably, the dispersant is one of EBS and PE wax.

[0014] The present invention also discloses a method for preparing the rigidity-enhanced and toughness-enhanced polypropylene composite material, comprising the following steps:

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

[0016] Step 2: Mixing: Add the pretreated raw materials 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;

[0017] Step 3, melt blending: add the mixed materials in step 2 into the 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 41, and feeding frequency 13.

[0018] Step 4: Extrusion granulation: The material after melt blending is extruded from the head of a twin-screw extruder, and is water-cooled, drawn into strips, and pelletized to obtain composite polypropylene material particles.

[0019] If the toughening agent used in step 1 is POE, it is first dried; the talc powder is dried at 100-120° C. for 3-5 hours to remove moisture.

[0020] Talc is a layered silicate mineral with a plate-like morphology due to weak van der Waals forces. When the shear stress is reduced, talc delaminates and becomes evenly distributed within the polymer matrix. This flaky structure positively impacts the rigidity and creep resistance of plastic materials at high temperatures, making it suitable for use as a reinforcing filler.

[0021] The layered talc is exfoliated by the shear forces of melt blending and dispersed into the matrix as a complete flake structure. This not only forms a comprehensive solid filler network but also regulates the aggregate structure, improving the composite's crystallization properties. This increases the crystallinity of the polymer matrix between the talc layers, while also acting as a barrier to the migration of small molecules within the matrix. Talc, when added as a heterogeneous nucleating agent, can induce high-temperature nucleation of PP in small amounts, expanding the temperature range for PP crystal nucleation and growth. This facilitates the production of a larger number of crystals and enhances crystallization, thereby improving the mechanical properties of PP.

[0022] The present invention selects talc powder with an optimal particle size and an optimal silicon content range to fill and modify the polypropylene material PP, thereby greatly enhancing the rigidity and toughness of the reduced propylene composite material product. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to specific examples, but the present invention is not limited to these embodiments.

[0024] Example 1:

[0025] Step 1, raw material preparation: weigh, by weight, 375 parts of homopolymer polypropylene resin (melt flow rate 18 g / 10 min, 230° C., 2.16 kg), 25 parts of ethylene-octene copolymer (POE), 100 parts of HYT-05C talc (particle size: 4.218 μm, silicon content: 59.56), 0.5 parts of antioxidant 1010, 1 part of antioxidant AT168, and 2.5 parts of EBS;

[0026] Step 2: Mixing: Add the pretreated raw materials 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;

[0027] Step 3, 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 1 180-190°C, zone 2 190-200°C, zone 3 200-210°C, zone 4 210-220°C, die head 190-210°C, main engine frequency 41, and feeding frequency 13;

[0028] Step 4: Extrusion granulation: The melt-blended material is extruded from the head of a twin-screw extruder, and is water-cooled, drawn, and pelletized to obtain composite polypropylene material particles.

[0029] Performance tests: The cantilever beam impact strength (23°C / notch 2mm), tensile strength (50mm / min), elongation at break (gauge length 50mm), bending performance (15mm / min), melt index (230°C / 2.16kg), shrinkage (23°C / 170.7mm) and density (23°C) of the polypropylene composite material prepared above were tested respectively.

[0030] Example 2:

[0031] Step 1, raw material preparation: weigh, by weight, 375 parts of homopolymer polypropylene resin (melt flow rate 18 g / 10 min, 230° C., 2.16 kg), 25 parts of ethylene-octene copolymer (POE), 100 parts of T-325 talc powder (particle size: 5.5 μm, silicon content: 60), 0.5 parts of antioxidant 1010, 1 part of antioxidant AT168, and 2.5 parts of EBS;

[0032] Step 2: Mixing: Add the pretreated raw materials 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;

[0033] Step 3, 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 1 180-190°C, zone 2 190-200°C, zone 3 200-210°C, zone 4 210-220°C, die head 190-210°C, main engine frequency 41, and feeding frequency 13;

[0034] Step 4: Extrusion granulation: The melt-blended material is extruded from the head of a twin-screw extruder, and is water-cooled, drawn into strands, and pelletized to obtain composite polypropylene material particles.

[0035] Performance tests: The cantilever beam impact strength (23℃ / notch 2mm), tensile strength (50mm / min), elongation at break (gauge length 50mm), bending performance (15mm / min), melt index (230℃ / 2.16kg), shrinkage (23℃ / 170.7mm) and density (23℃) of the obtained polypropylene composite materials were tested respectively.

[0036] Example 3

[0037] Step 1, raw material preparation: by weight, weigh 150 parts of homopolymer polypropylene resin (melt flow rate 18 g / 10 min, 230 ° C, 2.16 kg), 225 parts of copolymer polypropylene resin (melt flow rate 25 g / 10 min, 230 ° C, 2.16 kg), 25 parts of ethylene-octene copolymer (POE), 100 parts of HYT-05C (particle size: 4.218 μm, silicon content: 59.56), talc powder, 0.5 parts of antioxidant 1010, 1 part of antioxidant AT168, and 2.5 parts of EBS;

[0038] Step 2: Mixing: Add the pretreated raw materials 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;

[0039] Step 3, 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 1 180-190°C, zone 2 190-200°C, zone 3 200-210°C, zone 4 210-220°C, die head 190-210°C, main engine frequency 41, and feeding frequency 13;

[0040] Step 4: Extrusion granulation: The melt-blended material is extruded from the head of a twin-screw extruder, and is water-cooled, drawn into strands, and pelletized to obtain composite polypropylene material particles.

[0041] Performance tests: The cantilever beam impact strength (23℃ / notch 2mm), tensile strength (50mm / min), elongation at break (gauge length 50mm), bending performance (15mm / min), melt index (230℃ / 2.16kg), shrinkage (23℃ / 170.7mm) and density (23℃) of the obtained polypropylene composite materials were tested respectively.

[0042] Example 4

[0043] Step 1, raw material preparation: by weight, weigh 375 parts of homopolymer polypropylene resin (melt flow rate 18 g / 10 min, 230 ° C, 2.16 kg), 25 parts of ethylene-octene copolymer (POE), 100 parts of T-325 talc powder (particle size: 5.5 μm, silicon content: 60), 0.5 parts of antioxidant 1010, 1 part of antioxidant AT168, and 2.5 parts of EBS.

[0044] Step 2: Mixing: Add the pretreated raw materials 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.

[0045] Step 3, melt blending: add the mixed materials into the 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 41, and feeding frequency 13.

[0046] Step 4: Extrusion granulation: The melt-blended material is extruded from the head of a twin-screw extruder, and is water-cooled, drawn into strands, and pelletized to obtain composite polypropylene material particles.

[0047] Tests: The composite materials were tested for Izod impact strength (23°C / notch 2mm), tensile strength (50mm / min), elongation at break (gauge length 50mm), flexural properties (15mm / min), melt index (230°C / 2.16kg), shrinkage (23°C / 170.7mm) and density (23°C).

[0048] Table 1 Performance test results of materials prepared in various embodiments

[0049]

[0050] The results in Table 1 show that the polypropylene composite material prepared in the present invention has excellent rigidity and toughness.

[0051] The present invention determines the optimal particle size and silicon content range of talc powder used in PP filling modification, thereby greatly enhancing the rigidity and toughness of polypropylene composite products.

[0052] 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 polypropylene composite material with increased rigidity and toughness, characterized in that: In parts by weight, the components and proportions of the polypropylene composite material are: 300-425 parts of polypropylene resin, 25-50 parts of toughening agent, 50-150 parts of talc powder, 1.5 parts of antioxidant, and 2.5 parts of dispersant.

2. The polypropylene composite material according to claim 1, characterized in that 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).

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 method for preparing a polypropylene composite material with increased rigidity and toughness according to claim 1, wherein: The following steps are involved: Step 1: Raw material pretreatment: weigh polypropylene, toughening agent, talc, antioxidant and dispersant according to the proportion; Step 2: Mixing: Add the pretreated raw materials 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 3, 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 1 180-190°C, zone 2 190-200°C, zone 3 200-210°C, zone 4 210-220°C, die head 190-210°C, main engine frequency 41, and feeding frequency 13; Step 4: Extrusion granulation: The melt-blended material is extruded from the head of a twin-screw extruder, and is water-cooled, drawn into strands, and pelletized to obtain composite polypropylene material particles.

8. The method for preparing a polypropylene composite material with increased rigidity and toughness according to claim 1, wherein: The talc powder is dried in advance at 100-120° C. for 3-5 hours to remove moisture.

Images