Polypropylene composite material as well as preparation method and application thereof

Abstract

The invention discloses a polypropylene composite material which comprises the following components in parts by weight: 19-51 parts of first polypropylene; 5-30 parts of second polypropylene; 5-10 parts of an elastomer; 10 to 20 parts of talcum powder; 0.2 to 0.4 part of a dispersant; 0.1 to 0.7 part of magnesium aluminum hydrotalcite; and 0.1-0.3 part of a porous adsorbent. The dispersing agent is introduced to improve the dispersion of the second polypropylene and the inorganic matter, and the talcum powder, the magnesium-aluminum hydrotalcite and the porous adsorbent with specific particle sizes are introduced to improve the foaming performance of the system under high-humidity and high-temperature conditions due to acidity.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a polypropylene composite material and a preparation method and application thereof. Background Art

[0002] Polypropylene has many advantages such as light density, high industrialization, wide variety and low cost, and is widely used in automotive interior and exterior decoration and functional parts. Major OEMs have begun to conduct preliminary research or require the use of some recycled materials in the injection molding process of parts. At the same time, due to the trend of electric vehicles, there will be more design innovations in shape than traditional fuel vehicles. Under the premise of relatively low density, the requirements for material fluidity, rigidity and toughness are higher than traditional materials.

[0003] However, because the recycled materials have been used once, their molecular chains are shortened, the molecular weight changes, and their mechanical properties such as bending modulus and notched impact strength are relatively attenuated; secondly, small molecular weight substances can be further sheared in the subsequent modification and injection molding process, the molecular chain segments are further reduced, and acidic substances are generated. This causes bubbles to appear in parts under high temperature and high humidity (40°C temperature, 100% humidity for 240 hours), which in turn causes the appearance of sprayed parts to be poor under high temperature and high humidity conditions. Summary of the invention

[0004] The purpose of the present invention is to overcome the above technical defects and provide a polypropylene composite material with high modulus and the advantages of not being easy to bubble under the conditions of 40°C temperature and 100% humidity, as well as a preparation method and application thereof.

[0005] The present invention is achieved through the following technical solutions: A polypropylene composite material, comprising the following components in parts by weight: 19-51 parts of first polypropylene; 5-30 parts of the second polypropylene; Elastomer 5-10 parts; 10-20 parts of talcum powder; Dispersant 0.2-0.4 parts; 0.1-0.7 parts of magnesium aluminum hydrotalcite; 0.1-0.3 parts of porous adsorbent; The average particle size of the magnesium aluminum hydrotalcite is in the range of 0.1 μm to 2.0 μm, the average particle size of the talcum powder is in the range of 1 to 20 μm, and the average particle size of the porous adsorbent is in the range of 1 μm to 20 μm.

[0006] The polypropylene resin content in the second polypropylene is 95-99 wt%, and the polyethylene content is 1-5 wt%; preferably, the second polypropylene is recycled, with a polypropylene resin content of 95-99 wt% and a polyethylene content of 1-5 wt%, and it can be sourced from the corrugated inner barrel of a washing machine.

[0007] The melt index range of the first polypropylene and the second polypropylene applicable to the present invention is 10-50 g / 10 min (2.16 kg, 230 °C), and the test standard is ISO 1183.

[0008] In the polypropylene composite material of the present invention, the sum of the first polypropylene and the second polypropylene accounts for not less than 40 wt% of the total weight, and the second polypropylene accounts for not less than 5 wt% of the total weight.

[0009] The elastomer is a polyolefin elastomer, and the polyolefin elastomer is selected from at least one of ethylene-octene copolymer and ethylene-butene copolymer, preferably ethylene-octene copolymer.

[0010] Preferably, the average particle size range of the talcum powder is 8-12 μm; The dispersant is selected from at least one of polyolefin-based hyperdispersants, amide-based dispersants, and stearic acid-based dispersants.

[0011] The polyolefin-based hyperdispersant is a hyperbranched polymerized dispersant.

[0012] The amide-based dispersant is a stearic acid amide-based lubricant.

[0013] The stearic acid-based dispersant is zinc stearate or calcium stearate.

[0014] The porous adsorbent is selected from at least one of molecular sieves, diatomaceous earth, and porous silicates, and its pore size range is 0.3-50 nm.

[0015] Preferably, the average particle size range of the porous adsorbent is 8-12 μm; The average particle sizes of the magnesium aluminum hydrotalcite, talcum powder, and porous adsorbent in the present invention are tested by a laser particle size analyzer.

[0016] It is possible to choose whether to add 0-2 parts of additives according to the actual situation, and the additives are selected from at least one of antioxidants and light stabilizers.

[0017] Preparation method of polypropylene composite material, comprising the following steps: Mix each component evenly according to the ratio, and extrude and pelletize through a twin-screw extruder to obtain the polypropylene composite material. Among them, the temperature of the screw is set as follows: the temperature of zone 1 is 75 - 85°C, the temperature of zone 2 is 185 - 195°C, the temperature of zone 3 is 185 - 195°C, the temperature of zone 4 is 185 - 195°C, the temperature of zone 5 is 185 - 195°C, the temperature of zone 6 is 185 - 195°C, the temperature of zone 7 is 185 - 195°C, the temperature of zone 8 is 185 - 195°C, the temperature of zone 9 is 185 - 195°C; the main machine speed is 400 - 500 revolutions per minute; the length-diameter ratio of the twin-screw extruder is (44 - 48):1.

[0018] It is also possible to pre-mix the talcum powder and the dispersant evenly.

[0019] The polypropylene composite material of the present invention is used for preparing vehicle-mounted parts, especially suitable for vehicle-mounted parts with coatings on the surface, such as sprayed bumpers, sprayed side beams, all-plastic tailgate outer panels and other parts.

[0020] The present invention has the following beneficial effects: The present invention improves the modulus by introducing an elastomer and talcum powder with a specific average particle size, improves the dispersion of recycled polypropylene and inorganic substances by introducing a dispersant and thus improves the mechanical properties. At the same time, introducing specific average particle size of magnesium aluminum hydrotalcite and porous adsorbent can reduce the acidity of the system, improve degradation and thus increase the modulus, and can also improve the defect of easy foaming of the polypropylene composite material caused by the influence of the system acidity under the conditions of high temperature and high humidity (40°C, 100% humidity, 240 hours). Specific embodiments

[0021] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made. These all belong to the protection scope of the present invention.

[0022] The sources of the raw materials used in the present invention are as follows: The first polypropylene A: PP EP548RQ, Tianjin Petrochemical; The first polypropylene B: PP SP179 (Lanzhou Petrochemical), Lanzhou Petrochemical; The second polypropylene: sourced from the inner barrel of a corrugated washing machine, and after pulverization, raw material particles are obtained, with a polypropylene resin content of 98 wt% and a polyethylene content of 2 wt%.

[0023] The elastomer A: ethylene-butene copolymer, POE ENAGE 7447, Dow Chemical; The elastomer B: ethylene-octene copolymer, POE ENAGE 8842, Dow Chemical; The talcum powder was purchased from Guangzhou Tianyuan and then different raw materials with different average particle sizes were obtained through screening: Talcum powder A: The average particle size is 1.34 μm; Talcum powder B: The average particle size is 8.34 μm; Talcum powder C: The average particle size is 12.0 μm; Talcum powder D: The average particle size is 18.69 μm; Talcum powder E: The average particle size is 0.42 μm; Talcum powder F: The average particle size is 29.41 μm; Dispersant A: Hyperbranched polymeric dispersant, grade HBP-158, Wuhan Hyperbranched Resin Technology Co., Ltd.; Dispersant B: Amide dispersant, TR451, Struktol; Dispersant C: Stearic acid dispersant, SAK-ZS-P, Singapore Sanyi; The magnesium-aluminum hydrotalcite was purchased from Kyowa Chemical Industry Co., Ltd. of Japan, and different raw materials with different average particle sizes were obtained through screening: Magnesium-aluminum hydrotalcite A: The average particle size is 0.37 μm; Magnesium-aluminum hydrotalcite B: The average particle size is 1.95 μm; Magnesium-aluminum hydrotalcite C: The average particle size is 0.07 μm; Magnesium-aluminum hydrotalcite D: The average particle size is 4.77 μm; Molecular sieve 13X was purchased from Dalian Haixin, and then different raw materials with different average particle sizes were obtained through screening: Molecular sieve A: The average particle size is 1.15 μm; Molecular sieve B: The average particle size is 8.08 μm; Molecular sieve C: The average particle size is 11.69 μm; Molecular sieve D: The average particle size is 19.73 μm; Molecular sieve E: The average particle size is 0.51 μm; Molecular sieve F: The average particle size is 28.48 μm; Diatomite: No. 611, Shengzhou Xinglong, the average particle size after screening is 10.4 μm; Porous silicate: KF-AB201, Chongqing Baozhuan, the average particle size is 5 ± 0.5 μm; Antioxidant: Antioxidant 1010 and Antioxidant 168, the mixing ratio is 1:1, Tianjin Lian An Long.

[0024] Preparation methods of the example and comparative example polypropylene composites: According to the ratio, mix each component evenly, and extrude and pelletize through a twin-screw extruder to obtain the polypropylene composites. Among them, the temperature of the screw is set as follows: the temperature of zone 1 is 80°C, the temperature of zone 2 is 190°C, the temperature of zone 3 is 190°C, the temperature of zone 4 is 190°C, the temperature of zone 5 is 190°C, the temperature of zone 6 is 190°C, the temperature of zone 7 is 190°C, the temperature of zone 8 is 190°C, the temperature of zone 9 is 190°C; the main machine speed is 450 revolutions per minute; the length-diameter ratio of the twin-screw extruder is 48:1.

[0025] Each test method: (1)Flexural modulus: Adopt the ISO 178 test standard. Under the condition of 23°C, with a speed of 2 mm / min and a span of 64 mm, the required flexural modulus is 1700 - 1900 MPa.

[0026] (2)Test for resistance to condensation water blistering on the material surface: To save test time, it is equivalently replaced by boiling in water at 90°C for 4 hours. Specifically: The material adopts the test standard of ISO 4628-1-2003, using a 100 cm * 100 cm sample plate. Place the sample plate in a constant temperature water bath at 90°C and boil it for 4 h. After boiling, take out the sample plate and place it at room temperature. It is required to observe the sample plate 24 hours after the test, visually check the density and size of the bubbles on the sample plate, and the blistering grade < 2S2 level.

[0027] Among them, the first number represents the blister density; 0: No defect; 1: Very few defects; 2: Relatively few defects; 3: Moderate number of defects; 4: Relatively large number of defects; 5: Very large number of defects.

[0028] Among them, the number after S represents the blister size; 0: Invisible under 10 times magnification; 1: Visible only under 10 times magnification; 2: Visible to the naked eye; 3: Size less than 0.5 mm; 4: Size 0.5 - 5 mm; 5: Size greater than 5 mm.

[0029] Table 1: Weight parts of each component and test results of the polypropylene composites in Examples 1 - 7 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 First Polypropylene A 20 50 First Polypropylene B 35 35 35 35 35 Second Polypropylene 5 20 30 20 20 20 20 Elastomer A 5 8 10 8 8 8 8 Talc A 10 15 20 15 15 15 15 Dispersant A 0.2 0.3 0.4 0.3 0.3 Dispersant B 0.3 Dispersant C 0.3 Magnesium Aluminum Hydrotalcite A 0.1 0.4 0.7 0.4 0.4 0.4 0.4 Molecular Sieve A 0.1 0.2 0.3 0.2 0.2 Diatomite 0.2 Porous Silicate 0.2 Antioxidant / 0.2 0.2 0.2 0.2 0.2 0.2 Flexural Modulus, MPa 1820 1717 1811 1711 1744 1752 1738 Condensate Foaming 1S1 1S1 0S0 1S1 1S1 1S1 1S1 Table 2: Weight parts of each component and test results of the polypropylene composites in Examples 8 - 12 Example 8 Example 9 Example 10 Example 11 Example 12 First Polypropylene B 35 35 35 35 35 Second Polypropylene 20 20 20 20 20 Elastomer A 8 8 8 8 Elastomer B 8 Talc A 15 15 Talc B 15 Talc C 15 Talc D 15 Dispersant A 0.3 0.3 0.3 0.3 0.3 Magnesium Aluminum Hydrotalcite A 0.4 0.4 0.4 0.4 Magnesium Aluminum Hydrotalcite B 0.4 Molecular Sieve A 0.2 0.2 Molecular Sieve B 0.2 Molecular Sieve C 0.2 Molecular Sieve D 0.2 Antioxidant 0.2 0.2 0.2 0.2 0.2 Flexural Modulus, MPa 1822 1803 1752 1728 1704 Condensate Foaming 1S1 1S1 0S0 0S0 1S1 As can be seen from Examples 2 / 10 - 12, the preferred examples of the average particle size of talcum powder and porous adsorbent have better high-temperature and high-humidity foaming resistance (i.e., condensation water resistance foaming performance) and flexural modulus.

[0030] As can be seen from Example 2 / 8, when the elastomer is preferably ethylene-octene copolymer, the flexural modulus is higher.

[0031] Table 3: Parts by weight of each component of polypropylene composites in Comparative Examples 1 - 6 and test results Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 First Polypropylene B 35 35 35 35 35 35 Second Polypropylene 20 20 20 20 20 20 Elastomer A 8 8 8 8 8 8 Talc A 15 15 15 15 Talc E 15 Talc F 15 Dispersant A 0.3 0.3 0.3 0.3 0.3 0.3 Magnesium Aluminum Hydrotalcite A 0.4 0.4 0.4 0.4 Magnesium Aluminum Hydrotalcite C 0.4 Magnesium Aluminum Hydrotalcite D 0.4 Molecular Sieve A 0.2 0.2 0.2 0.2 Molecular Sieve E 0.2 Molecular Sieve F 0.2 Antioxidant 0.2 0.2 0.2 0.2 0.2 0.2 Flexural Modulus, MPa 1667 1649 1683 1701 1707 1690 Condensate Foaming 1S1 1S1 2S2 2S3 2S2 2S2 As can be seen from Comparative Example 1 / 2, when the average particle size of talcum powder is too small or too large, the mechanical properties are insufficient.

[0032] As can be seen from Comparative Examples 3 / 4, when the average particle size of magnesium-aluminum hydrotalcite is too small or too large, the acid absorption of the system is insufficient and the condensation water resistance foaming performance is insufficient.

[0033] As can be seen from Comparative Examples 5 / 6, when the average particle size of molecular sieve is too small or too large, the acid absorption of the system is insufficient and the condensation water resistance foaming performance is insufficient.

[0034] Table 4: Parts by weight of each component of polypropylene composites in Comparative Examples 7 - 10 and test results Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 First Polypropylene B 35 35 35 35 Second Polypropylene 20 20 20 20 Elastomer A 8 8 8 8 Talc A 15 15 15 0 Dispersant A 0.3 0.3 0.3 0.3 Magnesium Aluminum Hydrotalcite A 0 1.5 0.4 0.4 Molecular Sieve A 0.2 0.2 0 0.2 Antioxidant 0.2 0.2 0.2 0.2 Flexural Modulus, MPa 1604 1687 1631 1119 Condensate Foaming 2S3 1S1 2S2 2S2 As can be seen from Comparative Example 7, when magnesium-aluminum hydrotalcite is not contained, the acidity of the system is too high, not only the condensation water resistance foaming performance is poor, but also the mechanical properties decline.

[0035] As can be seen from Comparative Example 8, if the content of magnesium-aluminum hydrotalcite is too high, the flexural modulus will start to decline, and it is difficult to further improve the anti-condensation water foaming performance.

[0036] As can be seen from Comparative Example 9, when molecular sieve is not contained, the anti-condensation water foaming performance is insufficient.

[0037] As can be seen from Comparative Example 10, when talcum powder is not contained, the flexural modulus is poor and the anti-condensation water foaming performance also declines.

Claims

1. A polypropylene composite material, characterized in that: By weight, it includes the following components: 19-51 parts of first polypropylene; 5-30 parts of the second polypropylene; Elastomer 5-10 parts; 10-20 parts of talcum powder; Dispersant 0.2-0.4 parts; 0.1-0.7 parts of magnesium aluminum hydrotalcite; 0.1-0.3 parts of porous adsorbent; The average particle size of the magnesium aluminum hydrotalcite is in the range of 0.1 μm to 2.0 μm, the average particle size of the talcum powder is in the range of 1 to 20 μm, and the average particle size of the porous adsorbent is in the range of 1 μm to 20 μm.

2. The polypropylene composite material according to claim 1, characterized in that: The second polypropylene is recycled polypropylene, wherein the polypropylene resin content is 95-99wt% and the polyethylene content is 1-5wt%.

3. The polypropylene composite material according to claim 1, characterized in that: The elastomer is a polyolefin elastomer, and the polyolefin elastomer is selected from at least one of ethylene-octene copolymer and ethylene-butene copolymer, preferably ethylene-butene copolymer.

4. The polypropylene composite material according to claim 1, characterized in that: The average particle size of the talcum powder is 8-12 μm.

5. The polypropylene composite material according to claim 1, characterized in that: The dispersant is selected from at least one of polyolefin type super dispersants, amide dispersants and stearic acid dispersants.

6. The polypropylene composite material according to claim 1, characterized in that: The porous adsorbent is selected from at least one of molecular sieves, diatomaceous earth and porous silicate, and the average particle size of the porous adsorbent is in the range of 7 μm to 12 μm.

7. The polypropylene composite material according to claim 1, characterized in that: By weight, the invention further comprises 0-2 parts of auxiliary agents, wherein the auxiliary agents are selected from at least one of antioxidants and light stabilizers.

8. The method for preparing the polypropylene composite material according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: mixing the components uniformly according to the proportion, extruding and granulating through a twin-screw extruder to obtain a polypropylene composite material.

9. A vehicle-mounted component made of the polypropylene composite material according to any one of claims 1 to 7.