Low-odor reinforced polypropylene composite material and preparation method thereof

Abstract

The invention discloses a low-odor reinforced polypropylene composite material and a preparation method thereof. The low-odor reinforced polypropylene composite material is prepared from 55-90 parts by weight of polypropylene resin, 5-40 parts by weight of glass fibers, 2-5 parts by weight of polypropylene grafted glycidyl methacrylate, 0.5-3 parts by weight of a composite adsorbent and 0.5-2 parts by weight of other auxiliary agents. Wherein the composite adsorbent is formed by compounding an inorganic carrier with an adsorption function and an organic component with an adsorption or catalytic conversion function. Through a whole-process solution integrating'source reduction-process adsorption / catalysis-deep desorption ', the odor and the VOCs content of the glass fiber reinforced polypropylene composite material are remarkably reduced, and meanwhile, the core mechanical properties of high strength and high toughness of the glass fiber reinforced polypropylene composite material are completely kept.

Description

Technical Field

[0001] This invention relates to the field of polymer material modification technology, specifically to a low-odor reinforced polypropylene composite material and its preparation method. Background Technology

[0002] Polypropylene (PP) and its glass fiber reinforced composites are widely used in the automotive interior field, but the volatile organic compounds (VOCs) and irritating odors generated during their processing and use severely restrict their application in high-end models.

[0003] To reduce odor, existing technologies have evolved from single physical adsorption to multi-mechanism synergistic approaches. For example, CN101469094A discloses the use of modified attapulgite for physical adsorption; CN118652569A and CN119931203A respectively propose aminated zeolite-supported catalysts and COF@ZnO composite materials, attempting to combine adsorption and catalytic functions. Industry research (see "Research Progress on Low-Odor Polypropylene Composite Materials for Automotive Use") also points out that combining different functional materials (such as large specific surface area adsorbents with molecular sieves or metal oxide catalysts) is an important direction for improving odor removal efficiency.

[0004] However, existing synergistic schemes based on binary composites still have significant limitations: 1. Insufficient synergistic efficiency: Simple "adsorption + catalysis" combinations often lack efficient internal interaction channels, resulting in limited catalytic conversion efficiency for small molecule strong odor substances; 2. Difficulty in achieving both performance and quality: The excessive addition of functional components in pursuit of deodorization effects can easily damage the mechanical strength and toughness of glass fiber reinforced polypropylene. 3. Unsatisfactory long-term effect: The saturation problem of physical adsorption has not been fundamentally solved, and there is a risk of odor rebound.

[0005] Therefore, how to achieve deep and long-lasting odor removal while fully maintaining the core mechanical properties of the material has become a technical challenge that urgently needs to be overcome in this field. Summary of the Invention

[0006] In view of this, the present invention provides a low-odor reinforced polypropylene composite material and its preparation method to solve the problems mentioned in the background art. Through a complete process solution integrating "source reduction - process adsorption / catalysis - deep desorption", the odor and VOCs content of glass fiber reinforced polypropylene composite material are significantly reduced while its core mechanical properties of high strength and high toughness are fully maintained.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention first provides a low-odor reinforced polypropylene composite material, which is prepared by weight of 55-90 parts polypropylene resin, 5-40 parts glass fiber, 2-5 parts polypropylene grafted glycidyl methacrylate (PP-g-GMA), 0.5-3 parts composite adsorbent, and 0.5-2 parts other additives. The composite adsorbent is composed of an inorganic carrier with adsorption function and an organic component with adsorption or catalytic conversion function.

[0008] Furthermore, the polypropylene resin is a homopolymer polypropylene resin, and the melt flow rate at 230℃ and 2.16kg is (1-100) g / 10min. Furthermore, the glass fiber is a continuous alkali-free glass fiber with a single filament diameter of 10-20 μm.

[0009] Furthermore, the polypropylene grafted with glycidyl methacrylate has a melt flow rate of (20-100) g / 10 min at 230°C and 2.16 kg, a grafting rate of 1%-2%, and a GMA monomer residual content of less than 500 ppm.

[0010] Furthermore, the inorganic carrier is attapulgite soil with a specific surface area ≥350 m². 2 / g, with a pore size of 2-50 nm.

[0011] Furthermore, the organic component is a mixture of 13X molecular sieve and cerium oxide in a weight ratio of 1:1, both of which are industrial grade.

[0012] Furthermore, the weight ratio of the inorganic carrier to the organic component is (1-3):(0.5-2).

[0013] Furthermore, the other additives include at least one of antioxidants, light stabilizers, lubricants, and pigments. Their addition is not particularly limited and can be selected as needed. The antioxidants, light stabilizers, lubricants, and pigments are all conventional additives in the art. For example, the antioxidants include primary antioxidants and secondary antioxidants. The primary antioxidant can be a hindered phenolic antioxidant, and the secondary antioxidant can be a phosphite antioxidant. Antioxidants can be used alone or in combination. The light stabilizer can be a hindered amine light stabilizer. The lubricant can be zinc stearate, calcium stearate, polyethylene wax, etc., and can be used alone or in combination. The pigment can be selected from carbon black, etc., and can dye the material into different colors according to different needs. Since these are all known additives, they will not be described in detail here.

[0014] The present invention also provides a method for preparing a low-odor reinforced polypropylene composite material as described in any of the preceding claims, comprising the following steps: S1. Activate the molecular sieve at 350-400℃ for 2-4 hours, activate the attapulgite at 200-350℃ for 2-4 hours, and activate the cerium oxide at 105-120℃ for 2-4 hours. S2. Thoroughly mix the treated attapulgite, molecular sieve, and cerium oxide to obtain a composite adsorbent; S3. The glass fiber is prepared for use after surface cleaning. S4. Polypropylene resin, polypropylene grafted glycidyl methacrylate, composite adsorbent and other additives are thoroughly mixed and added from the main feed port of the twin-screw extruder. The treated glass fiber is added from the exhaust port of the twin-screw extruder. After melt blending, extrusion pelletizing and odor post-treatment, a low-odor reinforced polypropylene composite material is obtained. In this process, melt two-stage devolatilization-adsorption purification is carried out simultaneously during melt blending and extrusion pelletizing.

[0015] Furthermore, in step S4, the odor post-treatment adopts a three-tank series drying method, the drying temperature is 120-140℃, and the drying hot air blower power is greater than 60kW.

[0016] Furthermore, the surface cleaning treatment involves placing glass fibers at 80°C. Thoroughly purge under a nitrogen atmosphere at 100℃.

[0017] Furthermore, the melt undergoes two-stage devolatilization. Adsorption and purification include: First-stage devolatilization: A vacuum is drawn after the extruder exhaust port, with a vacuum level of [missing information]. 0.06~ 0.08 MPa; Second-stage devolatilization: Vacuuming is performed in zone 10 of the extruder, with a vacuum level of [missing value]. 0.09~ 0.095 MPa; Furthermore, activated carbon adsorption devices are installed on the air inlet pipes of the vacuum pumps used for both vacuuming operations.

[0018] Furthermore, the temperatures of each zone of the twin-screw extruder are as follows: Zone 1 190-210℃, Zone 2 190-210℃, Zone 3 200-210℃, Zone 4 200-210℃, Zone 5 190-200℃, Zone 6 190-200℃, Zone 7 190-200℃, Zone 8 190-200℃, Zone 9 190-200℃, and Zone 10 190-200℃; the screw speed is 300-500 rpm.

[0019] Thirdly, this invention discloses the application of the aforementioned low-odor reinforced polypropylene composite material in the preparation of automotive interior parts. It can be used to prepare dashboard frames, etc.

[0020] The principle of the low-odor reinforced polypropylene composite material provided by this invention is as follows: Polypropylene resin itself contains a small amount of volatile small molecules, which can be further generated during high-temperature melt processing due to molecular chain breakage, mainly including irritating substances such as aldehydes, esters, and ketones. This invention uses homopolymer polypropylene, whose molecular structure is simpler and purer than copolymer polypropylene, and therefore contains fewer volatile small molecules.

[0021] The main function of compatibilizers is to improve the interfacial compatibility between polypropylene and glass fiber. Conventional choices, such as coupling agents or anhydride grafts (e.g., PP-g-MAH), often contain a large amount of residual small molecules with an irritating odor. This invention uses polypropylene grafted with glycidyl methacrylate (PP-g-GMA), which is an epoxy graft and can improve compatibility through a ring-opening reaction between the epoxy groups and the polar groups on the glass fiber surface. Furthermore, PP-g-GMA itself contains very little residual monomer (GMA) and has almost no irritating odor.

[0022] Attapulgite has an extremely high specific surface area and nanoscale micropores, enabling it to efficiently adsorb high molecular weight volatile organic compounds (VOCs) during processing. Pre-processing heat treatment aims to remove pre-adsorbed impurities and restore its adsorption capacity.

[0023] A mixture of 13X molecular sieve and cerium oxide is used as the functional component to perform adsorption and catalytic conversion. 13X molecular sieve has a pore size of 10 Å, enabling efficient adsorption of small-molecule VOCs such as aromatics, branched hydrocarbons, aldehydes, and ketones. It is also heat-resistant (withstanding 600℃), and the pre-processing heat treatment is intended to remove pre-adsorbed volatile small molecules. Cerium oxide, as a metal oxide catalyst, can catalytically convert volatile small molecules (such as hydrocarbons) generated during processing into water and carbon dioxide, thereby fundamentally reducing odorous substances. Its pre-processing heat treatment aims to improve catalytic conversion efficiency.

[0024] Attapulgite, 13X molecular sieve, and cerium oxide exhibit a significant synergistic effect in VOC removal: Attapulgite, with its extremely large specific surface area (≥350 m² / g) and nanoscale micropores (2-50 nm), is primarily responsible for adsorbing high molecular weight VOCs; 13X molecular sieve, with its specific pore size, has a strong adsorption capacity for small molecule VOCs; and cerium oxide can catalytically oxidize some of the adsorbed small organic molecules into water and carbon dioxide, thereby preventing their re-release. This adsorption-conversion synergistic mechanism is key to achieving deep odor removal.

[0025] The catalytic mechanism of cerium oxide is based on its unique oxygen vacancy mechanism: cerium oxide has a fluorite-type crystal structure, and its catalytic activity originates from the abundant oxygen vacancies present in the crystal. At high temperatures, some Ce... 4+ Reduced to Ce 3+ This causes lattice oxygen to detach, forming positively charged oxygen vacancies. Oxygen molecules (O2) can adsorb onto these vacancies and be activated into highly reactive surface-adsorbed oxygen species, which in turn completely oxidize organic molecules (such as aldehydes).

[0026] The process of cerium oxide catalytic oxidation reaction can be simplified as follows: (1) Lattice oxygen release: CeO2 → CeO 2-x +x[O] lattice (Lattice oxygen) (2) Oxygen adsorption and activation: O2 + oxygen vacancy → 2O adss (Surface adsorption of oxygen) (3) Catalysis (taking acetaldehyde as an example) CH3CHO + 5[O] → 2CO2 + 2H2O (4) Reduction of Ce2O3 + 1 / 2O2 → 2CeO2 Before entering the extruder, the glass fibers pass through a hot air channel to remove residual wetting agents and other contaminants from their surface. During the extrusion process, a medium vacuum is drawn after the exhaust port to remove volatile gases generated by the degradation of macromolecules. A high vacuum is drawn in the tenth zone of the extruder to remove small molecules desorbed from the glass fiber surface and small molecules remaining in the melt. Activated carbon is added to the pipes of the two vacuum pumps to adsorb the extracted volatile substances and prevent secondary pollution.

[0027] In the post-treatment stage of particle odor, a three-tank series drying method is used. The composite material particles circulate continuously in the three tanks, while fresh air is introduced from the outside. With the help of a high-power hot air blower and high heating temperature, the trace small molecules remaining in the particles can be more effectively discharged.

[0028] Compared with the prior art, the beneficial effects of the present invention are: 1. Significantly low odor effect: By selecting low-odor homopolymer polypropylene and PP-g-GMA compatibilizer, odor sources are reduced at the source; and through a composite adsorbent with adsorption-catalysis synergistic function, VOCs are efficiently captured and converted during processing. The resulting composite material can achieve an odor level as low as 2.6-2.9, and the content of many characteristic VOCs is significantly lower than that of the comparative example.

[0029] 2. Multi-stage systematic control: Beyond simply adding adsorbents, it innovatively integrates glass fiber surface purification, two-stage vacuum online devolatilization of the melt, and high-temperature dynamic post-treatment of particles, forming a comprehensive low-odor control system from raw materials and processing to post-treatment. Comparative examples 6-10 demonstrate that the absence of any process step will lead to a decline in odor performance.

[0030] 3. Excellent performance balance: While achieving ultra-low odor, the core mechanical properties of the composite material are not compromised, and the high strength characteristics of glass fiber reinforced polypropylene are maintained, perfectly balancing the dual requirements of low odor and high strength.

[0031] 4. Suitable for automotive interiors: The product fully meets the odor and VOCs standards of automotive OEMs for interior materials, and is especially suitable for automotive interior components such as dashboard frames where odor requirements are stringent. Detailed Implementation

[0032] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0034] The specific information of the raw materials used in the following examples and comparative examples is as follows: Polypropylene resin, melt index (1-100) g / 10min (230℃, 2.16Kg), brand is Wuhan Petrochemical, grade is SZ30S; Glass fiber, with a single filament diameter of 10-20μm, brand name Taishan Glass Fiber, grade name TM315; Polypropylene grafted with glycidyl methacrylate (PP-g-GMA), melt index is (20-100) g / 10min (230℃, 2.16Kg), grafting rate is 1%-2%, GMA monomer residual content is less than 500ppm, brand is Shanghai Lihao; grade is ADK-01; Attapulgite, with a specific surface area ≥350 m2 / g and a pore size of 2-50 nm, is branded by Jiangsu Shenlite Mining and graded Ansac® 100. 13X molecular sieve, pore size 10Å, brand is Dalian Haixin Chemical.

[0035] Cerium oxide, industrial grade purity, brand name Sichuan Wonaixi, grade number 077.

[0036] In the examples and comparative examples, the molecular sieve, cerium oxide, and attapulgite were all pre-activated: the 13X molecular sieve was activated at 380°C for 3 hours, the attapulgite was activated at 280°C for 3 hours, and the cerium oxide was activated at 110°C for 3 hours.

[0037] The main antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], branded by BASF, Germany.

[0038] The co-antioxidant is tris[2,4-di-tert-butylphenyl]phosphite, branded by BASF, Germany.

[0039] The light stabilizer is 2-(2'-hydroxy-3',5'-bis(a,a-dimethylbenzyl)phenyl)benzotriazole, branded by BASF Germany, and designated as UV-P.

[0040] The lubricants include zinc stearate, calcium stearate, and polyethylene wax, branded as Dongguan Hanwei, grade AV300. All materials are commercially available, commonly used products.

[0041] It is understood that the above-mentioned raw materials and reagents are merely examples of some specific embodiments of the present invention, making the technical solution of the present invention clearer, and do not mean that the present invention can only use the above-mentioned reagents. The specific scope shall be determined by the claims. In addition, unless otherwise specified, "parts" in the examples and comparative examples refer to parts by weight.

[0042] Any range described in this invention includes the endpoint, any value between the endpoints, and any subrange consisting of the endpoint or any value between the endpoints.

[0043] Example 1 (1) Weigh 61 parts of polypropylene resin, 5 parts of polypropylene grafted glycidyl methacrylate, 30 parts of glass fiber, 2.6 parts of attapulgite, 0.3 parts of 13X molecular sieve, 0.3 parts of cerium oxide, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, 0.3 parts of light stabilizer, and 0.1 parts of lubricant.

[0044] (2) Glass fiber pretreatment: First, the glass fiber is purged with nitrogen at 90°C through a hot air duct to remove volatile pollutants adsorbed on its surface, and then set aside. (3) Add all the above raw materials except glass fiber to a high-speed mixer and stir for 3-5 minutes to obtain a uniformly mixed material. Add the mixture through the main feed port of the twin-screw extruder, and add the glass fiber through the hot air channel and then through the exhaust port of the twin-screw extruder. After melt blending, extrusion drawing and pelletizing, the mixture is processed.

[0045] During melt blending, extrusion drawing, and pelletizing, two-stage devolatilization and online purification are carried out simultaneously: the first stage of devolatilization is a medium vacuum of -0.07MPa after the exhaust port of the twin-screw extruder, and the second stage of devolatilization is a high vacuum of -0.095MPa in the tenth zone of the twin-screw extruder (both vacuuming continues until the end of pelletizing). At the same time, activated carbon treatment is added to the air inlet pipes of the two vacuum pumps.

[0046] (4) The composite material after pelleting is subjected to odor post-treatment to obtain low-odor reinforced polypropylene composite material. The odor post-treatment is as follows: the obtained composite material particles are dried in three tanks in series. The temperature of the drying tanks is 130℃, the power of the hot air blower is 85KW, and the drying time is 4h.

[0047] The temperatures of each zone of the twin-screw extruder are as follows: Zone 1 190℃, Zone 2 190℃, Zone 3 200℃, Zone 4 210℃, Zone 5 200℃, Zone 6 200℃, Zone 7 200℃, Zone 8 200℃, Zone 9 200℃, and Zone 10 190℃; the screw speed is 300-500 rpm. Example 2 (1) Weigh 60.2 parts of polypropylene resin, 5 parts of polypropylene grafted glycidyl methacrylate, 30 parts of glass fiber, 3 parts of attapulgite, 0.5 parts of 13X molecular sieve, 0.5 parts of cerium oxide, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, 0.3 parts of light stabilizer, and 0.1 parts of lubricant.

[0048] (2) Glass fiber pretreatment: First, the glass fiber is purged with nitrogen at 90°C through a hot air duct to remove volatile pollutants adsorbed on its surface, and then set aside. (3) Add all the above raw materials except glass fiber to a high-speed mixer and stir for 3-5 minutes to obtain a uniformly mixed material. Add the mixture through the main feed port of the twin-screw extruder, and add the glass fiber through the hot air channel and then through the exhaust port of the twin-screw extruder. After melt blending, extrusion drawing and pelletizing, the mixture is processed.

[0049] During the melt blending, extrusion drawing and pelletizing processes, two-stage devolatilization and online purification are carried out simultaneously: the first stage of devolatilization is a medium vacuum of -0.07MPa after the exhaust port of the twin-screw extruder, and the second stage of devolatilization is a high vacuum of -0.095MPa in the tenth zone of the twin-screw extruder (both vacuuming continues until the end of pelletizing). At the same time, activated carbon treatment is added to the air inlet pipes of the two vacuum pumps. The temperatures of each zone of the twin-screw extruder are as follows: Zone 1 190℃, Zone 2 190℃, Zone 3 200℃, Zone 4 210℃, Zone 5 200℃, Zone 6 200℃, Zone 7 200℃, Zone 8 200℃, Zone 9 200℃, and Zone 10 190℃; the screw speed is 300-500 rpm.

[0050] (4) The composite material after pelleting is subjected to odor post-treatment to obtain low-odor reinforced polypropylene composite material. The odor post-treatment is as follows: the obtained composite material particles are dried in three tanks in series. The temperature of the drying tanks is 130℃, the power of the hot air blower is 85KW, and the drying time is 4h.

[0051] Example 3 (1) Weigh 61.8 parts of polypropylene resin, 5 parts of polypropylene grafted glycidyl methacrylate, 30 parts of glass fiber, 2 parts of attapulgite, 0.2 parts of 13X molecular sieve, 0.2 parts of cerium oxide, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, 0.3 parts of light stabilizer, and 0.1 parts of lubricant.

[0052] (2) Glass fiber pretreatment: First, the glass fiber is purged with nitrogen at 90°C through a hot air duct to remove volatile pollutants adsorbed on its surface, and then set aside. (3) Add all the above raw materials except glass fiber to a high-speed mixer and stir for 3-5 minutes to obtain a uniformly mixed material. Add the mixture through the main feed port of the twin-screw extruder, and add the glass fiber through the hot air channel and then through the exhaust port of the twin-screw extruder. After melt blending, extrusion drawing and pelletizing, the mixture is processed.

[0053] During the melt blending, extrusion drawing and pelletizing processes, two-stage devolatilization and online purification are carried out simultaneously: the first stage of devolatilization is a medium vacuum of -0.07MPa after the exhaust port of the twin-screw extruder, and the second stage of devolatilization is a high vacuum of -0.095MPa in the tenth zone of the twin-screw extruder (both vacuuming continues until the end of pelletizing). At the same time, activated carbon treatment is added to the air inlet pipes of the two vacuum pumps. The temperatures of each zone of the twin-screw extruder are as follows: Zone 1 190℃, Zone 2 190℃, Zone 3 200℃, Zone 4 210℃, Zone 5 200℃, Zone 6 200℃, Zone 7 200℃, Zone 8 200℃, Zone 9 200℃, and Zone 10 190℃; the screw speed is 300-500 rpm.

[0054] (4) The composite material after pelleting is subjected to odor post-treatment to obtain low-odor reinforced polypropylene composite material. Odor post-treatment is as follows: the obtained composite material particles are dried in three tanks connected in series. The temperature of the drying tanks is 130℃, the power of the hot air blower is 85KW, and the drying time is 4h.

[0055] Comparative Example 1 (1) Weigh 64.2 parts of polypropylene resin, 5 parts of polypropylene grafted glycidyl methacrylate, 30 parts of glass fiber, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, 0.3 parts of light stabilizer, and 0.1 parts of lubricant.

[0056] Steps (2), (3), and (4) are the same as in Example 1.

[0057] Comparative Example 2 (1) Weigh 61 parts of polypropylene resin, 5 parts of polypropylene grafted glycidyl methacrylate, 30 parts of glass fiber, 3.2 parts of attapulgite, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, 0.3 parts of light stabilizer, and 0.1 parts of lubricant.

[0058] Steps (2), (3), and (4) are the same as in Example 1.

[0059] Comparative Example 3 (1) Weigh 61 parts of polypropylene resin, 5 parts of polypropylene grafted glycidyl methacrylate, 30 parts of glass fiber, 1.6 parts of 13X molecular sieve, 1.6 parts of cerium oxide, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, 0.3 parts of light stabilizer, and 0.1 parts of lubricant.

[0060] Steps (2), (3), and (4) are the same as in Example 1.

[0061] Comparative Example 4 (1) Weigh 61 parts of polypropylene resin, 5 parts of polypropylene grafted glycidyl methacrylate, 30 parts of glass fiber, 3.2 parts of 13X molecular sieve, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, 0.3 parts of light stabilizer, and 0.1 parts of lubricant.

[0062] Steps (2), (3), and (4) are the same as in Example 1.

[0063] Comparative Example 5 (1) Weigh 61 parts of polypropylene resin, 5 parts of polypropylene grafted glycidyl methacrylate, 30 parts of glass fiber, 3.2 parts of cerium oxide, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, 0.3 parts of light stabilizer, and 0.1 parts of lubricant.

[0064] Steps (2), (3), and (4) are the same as in Example 1.

[0065] Comparative Example 6 The preparation method is the same as in Example 1. The only difference is that there is no activated carbon treatment on the air inlet pipes of the exhaust port vacuum pump and the tenth zone vacuum pump in step (3).

[0066] Comparative Example 7 The preparation method is the same as in Example 1, except that the odor post-treatment in step (4) is omitted.

[0067] Comparative Example 8 The preparation method is the same as in Example 1, except that there is no activated carbon treatment on the air inlet pipe of the exhaust port vacuum pump in step (3).

[0068] Comparative Example 9 The preparation method is the same as in Example 1, except that there is no activated carbon treatment on the air inlet pipe of the vacuum pump in the tenth zone in step (3).

[0069] Comparative Example 10 The preparation method is the same as in Example 1, except that step (2) glass fiber pretreatment is omitted.

[0070] Test case The polypropylene composite materials obtained in Examples 1-3 and Comparative Examples 1-10 were subjected to tensile strength, flexural modulus, and cantilever beam notched impact strength tests, and the measured physical property results are shown in Table 1.

[0071] Table 1. Performance test results of recycled polypropylene composites in Examples 1-3 and Comparative Examples 1-10

[0072] The test method in Table 1 is as follows: the ambient temperature is (23±2)℃, the ambient humidity is (50±5)%, and all samples are placed in this environment for 24 hours for testing. 1. Impact properties of polypropylene composites: Cantilever beam impact tests were conducted according to the test methods of GB / T1843. The specimen size was 80×10×(4.0±0.2)mm, with a type A notch. 2. Tensile properties of polypropylene composites: Tensile tests were conducted according to the test methods of GB / T1040.2-2006, using type 1A injection molded specimens, at a test speed of 50 mm / min. 3. Bending properties of polypropylene composites: Bending tests were conducted according to the test method of GB / T9341-2008. The sample size was 80×10×(4.0±0.2)mm, the test speed was 2mm / min, and the support span was 64mm.

[0073] The polypropylene composite materials obtained in Examples 1-3 and Comparative Examples 1-10 were subjected to odor testing, and the results are shown in Table 2.

[0074] Table 2 Odor and VOC (μg / m³) of low-odor reinforced polypropylene composites in Examples 1-3 and Comparative Examples 1-10 3 Test results

[0075] The odor ratings in Table 2 are based on the Chang'an VS-00.28—L-06021 test, using a six-level scale from 1 to 6, where 6 is the highest level representing the worst odor and 1 is the lowest level representing the best odor. Generally, a level ≤3 is required to meet the standard. VOC testing is conducted according to Chang'an VS-00.28-L-06017.

[0076] As can be seen from the test results in Table 1, compared with the basic formulation without the composite adsorbent (Comparative Example 1), the tensile strength and flexural modulus of the three embodiments of the present invention remained stable and slightly improved, while the impact strength was significantly optimized (with a maximum improvement of 13.5%). This strongly demonstrates that the low-odor technical solution of the present invention, through the selection of compatibilizers and system processes, not only does not impair the mechanical properties of the materials, but also enhances the overall performance by improving interfacial bonding.

[0077] The odor test results in Table 2 show that: As can be seen from Examples 1-3 and Comparative Examples 1-5, attapulgite, 13X molecular sieve, and cerium oxide have a significant impact on the odor of the materials. The odor decreases with increasing amounts of attapulgite, 13X molecular sieve, and cerium oxide; furthermore, the effect is even better when attapulgite, 13X molecular sieve, and cerium oxide are added together. This result is because attapulgite, 13X molecular sieve, and cerium oxide have a synergistic effect. Attapulgite can efficiently adsorb large molecular weight volatile organic compounds, 13X molecular sieve can efficiently adsorb small molecule volatile organic compounds, and cerium oxide can catalytically oxidize small organic molecules into water and carbon dioxide.

[0078] As can be seen from Examples 1, 2, 4 and 5, attapulgite, 13X molecular sieve and cerium oxide have a synergistic effect, and the combined effect cannot be achieved by using any one of the adsorbents alone.

[0079] As can be seen from Example 1 and Comparative Example 6, removing the activated carbon from the two vacuum pump pipes significantly increases the odor of the material. This is because the volatile small molecules from the vacuum pump continue to diffuse into the material melt, leading to an increase in odor.

[0080] As can be seen from Example 1 and Comparative Example 7, the odor of the material increases dramatically when the subsequent particle drying treatment is omitted. This is because some volatile small molecules remain in the material and will continue to be emitted without drying treatment.

[0081] As can be seen from Example 1 and Comparative Examples 8 and 9, the odor of the material increases slightly when one vacuum pump is removed. This is because the extraction effect of one vacuum pump is weakened, and the content of volatile small molecules in the material melt increases.

[0082] As can be seen from Example 1 and Comparative Example 10, the odor also increases slightly when the glass fiber is not processed through the hot air channel, because the surface of the glass fiber contains a small amount of small molecules and contaminants with irritating odor.

[0083] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0084] Therefore, the above description is only a preferred embodiment of this application and is not intended to limit the scope of this application; that is, all equivalent modifications made in accordance with the scope of the claims of this application shall be within the protection scope of the claims of this application.

Claims

1. A low odor, enhanced polypropylene composite, characterized in that, It is prepared from polypropylene resin 55-90 parts, glass fiber 5-40 parts, polypropylene graft glycidyl methacrylate 2-5 parts, composite adsorbent 0.5-3 parts, other auxiliary 0.5-2 parts according to weight parts, wherein, the composite adsorbent is composed of inorganic carrier with adsorption function and organic component with adsorption or catalytic conversion function.

2. The low-odor, reinforced polypropylene composite of claim 1, wherein, The weight ratio of the inorganic carrier to the organic component is (1 3): (0.5 2).

3. The low-odor reinforced polypropylene composite of claim 2, wherein, The inorganic carrier is attapulgite; and / or, the organic component is a mixture of molecular sieve and cerium oxide.

4. The low odor, reinforced polypropylene composite of claim 1, wherein, The polypropylene is homopolymer polypropylene resin, and the melt flow rate thereof under the condition of 230 DEG C and 2.16 kg is 1-100 g / 10 min.

5. The low-odor reinforced polypropylene composite of claim 1, wherein, The polypropylene graft glycidyl methacrylate has a melt flow rate of 20-100 g / 10 min under the condition of 230 DEG C and 2.16 kg, a grafting rate of 1-2%, and a GMA monomer residual content of less than 500 ppm.

6. The low-odor, reinforced polypropylene composite of claim 1, wherein, The glass fiber is continuous alkali-free glass fiber, and the single filament diameter is 10-20 μm.

7. The low-odor reinforced polypropylene composite of claim 1, wherein, The other auxiliary is at least one of antioxidant, light stabilizer, lubricant and pigment.

8. A process for the preparation of a low-odour reinforced polypropylene composite material as claimed in any one of claims 1-7, characterised in that, The method comprises the following steps: S1, the molecular sieve is activated at 350-400 DEG C for 2-4 hours, the attapulgite is activated at 200-350 DEG C for 2-4 hours, and the cerium oxide is activated at 105-120 DEG C for 2-4 hours; S2, the treated attapulgite, molecular sieve and cerium oxide are mixed to obtain a composite adsorbent; S3, the glass fiber is reserved after surface purification; S4, the polypropylene resin, polypropylene graft glycidyl methacrylate, composite adsorbent and other auxiliary are mixed, the polypropylene resin, polypropylene graft glycidyl methacrylate, composite adsorbent and other auxiliary are added from the main feeding port of the double screw extruder, and the treated glass fiber is added from the exhaust port of the double screw extruder; low odor reinforced polypropylene composite material is obtained through melt blending, extrusion granulation and odor post-treatment. The melt two-stage devolatilization-adsorption purification is carried out synchronously during melt blending and extrusion granulation.

9. The preparation method according to claim 8, characterized in that, In step S4, the odor post-treatment adopts three-kettle series drying method, the drying temperature is 120-140 DEG C, and the drying air blower power is greater than 60 kW.

10. The preparation method according to claim 8, characterized in that, The surface cleaning treatment is to place the glass fiber in 80 100°C under nitrogen atmosphere.

11. The preparation method according to claim 8, characterized in that, The melt two-stage devolatilization The adsorptive purification comprises: First-stage devolatilization: A vacuum is drawn after the extruder exhaust port, with a vacuum level of [missing information]. 0.06~ 0.08 MPa; Second stage devolatilization: vacuum was applied in the tenth zone of the extruder at a vacuum level of 0.09 0.095 MPa; Active carbon adsorption devices are arranged on the vacuum pump inlet pipelines of the two vacuumizing processes.

12. The method of claim 8, wherein, The temperature of each zone of the double screw extruder is as follows: zone one 190-210 DEG C, zone two 190-210 DEG C, zone three 200-210 DEG C, zone four 200-210 DEG C, zone five 190-200 DEG C, zone six 190-200 DEG C, zone seven 190-200 DEG C, zone eight 190-200 DEG C, zone nine 190-200 DEG C, and zone ten 190-200 DEG C; and the screw rotation speed is 300-500 rpm.

13. The use of the low odor reinforced polypropylene composite material according to any one of claims 1-7 in the preparation of automobile interior parts.

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