High-durability long glass fiber reinforced polypropylene composite material and preparation method thereof

Abstract

The invention discloses a high-durability long glass fiber reinforced polypropylene composite material and a preparation method thereof. The composite material is prepared from the following raw materials in parts by weight: 40 to 80 parts of polypropylene resin, 20 to 60 parts of continuous glass fiber, 1 to 5 parts of compatilizer and 0.2 to 2 parts of durable additive. The flame retardant ammonium polyphosphate and aluminum hydroxide are combined with the epoxy resin to achieve a synergistic effect, the inorganic metal flame retardant aluminum hydroxide is used as a heat concentration point at high temperature, ammonium polyphosphate around the inorganic metal flame retardant aluminum hydroxide is decomposed to form a carbon layer to isolate oxygen, and meanwhile, the aluminum hydroxide and the epoxy resin neutralize acid substances generated by decomposition of ammonium polyphosphate, so that the flame retardant effect is improved. And the epoxy resin can also capture free peroxide, so that the degradation speed of the polypropylene is further reduced, and the thermo-oxidative aging life of the material is prolonged. The high-durability long glass fiber reinforced polypropylene composite material disclosed by the invention is a material which has high thermo-oxidative aging life and can be used for automobile parts with high service life requirements.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer materials, and particularly relates to a high-durability long-glass-fiber-reinforced polypropylene composite material and a preparation method thereof. BACKGROUND

[0002] Long-glass-fiber-reinforced polypropylene (PP-LFT) material plays an increasingly important role in the automotive field due to its excellent comprehensive performance. It not only can significantly reduce the weight of the automobile, thereby reducing fuel consumption and carbon emissions, meeting the core development trend of the current automobile industry lightweight and energy saving and emission reduction, but also has high specific strength, specific stiffness and good impact resistance, which can meet the stringent requirements of automobile structural parts on mechanical properties. In addition, the PP-LFT material also has good molding processability, which can realize one-time injection molding of complex parts, effectively improve production efficiency and reduce manufacturing cost, and its chemical stability and corrosion resistance also help to improve the service life of automobile parts. These characteristics make the PP-LFT material widely used in many key parts such as automobile bumper support, main and auxiliary instrument panel skeleton, door inner base plate, seat skeleton, chassis parts, etc., and become an important force to promote the upgrading and technological progress of automobile materials.

[0003] At present, the requirement for the heat-oxidative aging performance of PP-LFT material in the automotive field is continuously improved, which is mainly due to the following background technical factors. First, with the continuous development of automobile technology, the structure layout in the engine compartment is increasingly compact, resulting in a significant increase in the working temperature of the engine and surrounding parts. As a commonly used material for engine surrounding parts, the PP-LFT material is exposed to high temperature environment for a long time, and its heat-oxidative aging problem is increasingly prominent. Second, the rapid development of new energy vehicles puts forward higher requirements for the heat resistance of materials, especially in the areas around the battery pack and motor controller, not only the temperature is high, but also there are electric field, magnetic field and other composite stresses in some environments, which accelerate the heat-oxidative aging process of the material. Third, the automobile industry continuously improves the requirements for the service life and reliability of parts, and the PP-LFT material parts need to maintain stable mechanical properties and structural integrity in a longer service period, while heat-oxidative aging will lead to molecular chain rupture and crosslinking of the material, thereby reducing the strength and toughness of the material, affecting the safety and durability of the parts. In addition, the use of automobiles in different regions and climate conditions faces a larger temperature fluctuation range, and the frequency of extreme high temperature environment increases, which further tests the heat-oxidative aging performance of the PP-LFT material. Therefore, improving the heat-oxidative aging performance of the PP-LFT material has become one of the key directions of current automobile material research and development to meet the actual needs of the continuous development of the automobile industry. SUMMARY

[0004] In order to overcome the existing technical deficiencies, the application provides a kind of high durability long glass fiber reinforced polypropylene composite material.It is a kind of high-quality material developed to improve the heat-aging resistance of long glass fiber reinforced polypropylene composite material from the market.

[0005] The technical scheme adopted by the application to solve its technical problems is:

[0006] A kind of high durability long glass fiber reinforced polypropylene composite material is prepared from the following ingredients by weight parts: polypropylene resin 40-80 parts, continuous glass fiber 20-60 parts, compatibilizer 1-5 parts, and durability aid 0.2-2 parts.

[0007] The high durability long glass fiber reinforced polypropylene composite material described above,

[0008] The polypropylene resin is a blend of copolymerized polypropylene and homopolymerized polypropylene, with copolymerized polypropylene accounting for 55% and homopolymerized polypropylene accounting for 45%;

[0009] The continuous glass fiber is one of Tianshan Glass Fiber TCR738-2400 continuous glass fiber, Chongqing International 4305PM-2400 continuous glass fiber, or Owens Corning SE4805-2400 continuous glass fiber, or a combination of two.

[0010] The compatibilizer is one of MAH-g-PP, MAH-g-POE, or MAH-g-PS, or a combination of two.

[0011] The durability aid is a combination of ammonium polyphosphate, aluminum hydroxide, and epoxy resin.

[0012] The preparation method of the high durability long glass fiber reinforced polypropylene composite material described above has the following steps:

[0013] 1) The raw materials of polypropylene resin, compatibilizer, and durability aid are weighed according to the weight ratio, mixed uniformly in a high-speed mixer, and then fed into a dip tank through a twin-screw extruder;

[0014] 2) The continuous glass fiber is subjected to stretching, cooling, pelletizing, and drying after passing through the dip tank;

[0015] 3) The long glass fiber reinforced polypropylene material obtained in step 2 is injection molded into ISO standard bars for standby, with the bar specifications being 170*10*4mm.

[0016] The application adopts the above technical scheme, and the beneficial effects obtained are:

[0017] The application adopts the synergistic effect of the flame retardant ammonium polyphosphate and aluminum hydroxide combined with epoxy resin, uses the inorganic metal flame retardant aluminum hydroxide as a heat concentration point at high temperature to initiate the decomposition of the surrounding ammonium polyphosphate to form a carbon layer to isolate oxygen, and neutralizes the acid substances generated by the decomposition of ammonium polyphosphate in the epoxy resin, avoiding the catalysis of acid substances on the degradation of polypropylene, and the epoxy resin can also capture free-state peroxide, further slowing down the degradation rate of polypropylene and improving the thermal-oxidative aging life of the material. DETAILED DESCRIPTION

[0018] The technical solutions of the application are further illustrated below in combination with specific examples.

[0019] A high-durability long-glass-fiber-reinforced polypropylene composite material, which comprises (by weight): 40-80 parts of polypropylene resin, 20-60 parts of continuous glass fiber, 1-5 parts of compatibilizer, and 0.2-2 parts of durability aid.

[0020] The polypropylene used in the product is a blend of copolymerized polypropylene and homopolymerized polypropylene, wherein the copolymerized polypropylene accounts for 55%, and the homopolymerized polypropylene accounts for 45%; the continuous glass fiber used is Owens Corning SE4805-2400 continuous glass fiber; the compatibilizer used is MAH-g-PP with a grafting rate of 0.7%; and the durability aid used is a combination of ammonium polyphosphate, aluminum hydroxide and epoxy resin.

[0021] A preparation method of a high-durability long-glass-fiber-reinforced polypropylene composite material:

[0022] 1) The raw materials of polypropylene resin, compatibilizer and durability aid are weighed according to the weight ratio, and then put into a high-speed mixer for mixing, and then passed through a double-screw extruder into an impregnation tank;

[0023] 2) The continuous glass fiber is subjected to the processes of drawing, cooling, pelletizing and drying after passing through the impregnation tank;

[0024] 3) The long-glass-fiber-reinforced polypropylene material obtained in step 2 is injection molded into an ISO standard sample for standby, and the sample has a specification of 170*10*4mm.

[0025] Thermal-oxidative aging performance test method:

[0026] According to the ISO 188 standard, the injection-molded sample is placed in an environmental chamber, the temperature of the environmental chamber is set to 150℃, and the sample is taken out after being placed for a certain time for tensile strength test at a test speed of 5mm / min, the tensile strength retention rate before and after storage is calculated, and the calculation formula is: tensile strength retention rate = tensile strength after storage / tensile strength before storage*100%.

[0027] Table 1 shows the component allocation ratio and tensile strength retention rate test results of each example:

[0028]

[0029] Table 2. Results of the distribution ratio and tensile strength retention rate of each group in the comparative example:

[0030]

[0031] As can be seen from the performance of the above embodiments and comparative examples, the high-durability long glass fiber reinforced polypropylene composite material of the present invention uses a composite flame retardant as an antioxidant, which is practical. With a relatively small amount added, it can well meet the extremely high thermo-oxidative aging requirements of 150℃*2000h. Furthermore, the three components work synergistically, and the absence of any one component will lead to rapid aging and failure of the material. The high-durability long glass fiber reinforced polypropylene composite material of the present invention (Example 1) exhibits superior thermo-oxidative aging resistance compared to the long glass fiber reinforced polypropylene composite material using a traditional antioxidant system (Comparative Example 5). The preparation method of the high-durability long glass fiber reinforced polypropylene composite material of the present invention is simple to operate and can ensure that the long glass fiber reinforced polypropylene composite material has extremely excellent thermo-oxidative aging resistance, making it suitable for industrial production and application.

Claims

1. A high-durability long-glass-fiber-reinforced polypropylene composite material, characterized by, It is prepared from the following ingredients by weight parts: polypropylene resin 40-80 parts, continuous glass fiber 20-60 parts, compatibilizer 1-5 parts, durable auxiliary 0.2-2 parts.

2. The high-durability long-glass-fiber-reinforced polypropylene composite material according to claim 1, characterized in that, The polypropylene resin is a blend of copolymerized polypropylene and homopolymerized polypropylene, wherein the copolymerized polypropylene accounts for 55%, and the homopolymerized polypropylene accounts for 45%.

3. The high-durability long-glass-fiber reinforced polypropylene composite material according to claim 1, characterized in that, The continuous glass fiber is one of Tianshan Glass Fiber TCR738-2400 continuous glass fiber, Chongqing International 4305PM-2400 continuous glass fiber or Owens Corning SE4805-2400 continuous glass fiber or a combination of two.

4. The high-durability long-glass-fiber reinforced polypropylene composite material according to claim 1, characterized in that, The compatibilizer is one of MAH-g-PP, MAH-g-POE or MAH-g-PS or a combination of two.

5. The high-durability long-glass-fiber reinforced polypropylene composite material according to claim 1, characterized in that, The durable auxiliary is a combination of ammonium polyphosphate, aluminum hydroxide and epoxy resin.

6. The process for the production of high durable long glass fiber reinforced polypropylene composites according to any one of claims 1 to 5, characterized in that, The steps are as follows: 1) The raw materials of polypropylene resin, compatibilizer and durable auxiliary are weighed according to the weight ratio, the weighed raw materials are put into a high-speed mixer for mixing, and then they are put into a dipping tank through a double-screw extruder; 2) The continuous glass fiber is subjected to drawing, cooling, pelletizing and drying after passing through the dipping tank; 3) The long glass fiber reinforced polypropylene material obtained in step 2 is injection molded into ISO standard sample bars for standby, and the sample bar specifications are 170*10*4mm.

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