PA / PP (polyamide / polypropylene) composite material for vehicle runner plate as well as preparation method and application of PA / PP composite material

Abstract

The invention belongs to the field of polymer compositions, and particularly relates to a PA / PP composite material for a vehicle runner plate and a preparation method and application of the PA / PP composite material. The PA / PP composite material for the vehicle runner plate comprises the following components in parts by weight: 35-50 parts of PA6, 20-35 parts of PP, 25-35 parts of glass fibers, 0.2-0.5 part of an antioxidant and 0.3-0.6 part of a compatilizer, and the relative viscosity of the PA6 is 2.3-2.8. The melt index of the PP is 3-8 g / 10 min; the compatilizer is PP-co-MAH (polypropylene-co-maleic anhydride), and the content of the MAH is 40%-60%; the preparation method comprises the following steps: weighing and uniformly mixing the compatilizer and PP according to a formula, and carrying out melt blending and granulation through a double-screw extruder to obtain a premix; the preparation method comprises the following steps: weighing the rest components except the glass fiber according to the formula, uniformly mixing, adding the mixture and the premix from a main feeding port, adding the glass fiber into a double-screw extruder from a side feeding port, and carrying out melt blending and granulation to obtain the composite material. The composite material meets the long-term high-temperature alcoholysis-resistant performance index requirement, is low in cost, and can better replace a PA66 composite material to be applied to a runner plate of a vehicle heat management integrated module.

Description

Technical Field

[0001] The present invention belongs to the field of polymer compositions, and particularly relates to a PA / PP composite material for vehicle flow channel plates, a preparation method thereof, and an application thereof. Background Art

[0002] The thermal management of new energy vehicles directly affects the vehicle safety and service life. The flow channel plate, through its precisely designed internal flow channels (e.g., the main channel is connected to the water pump, and the branch channels lead to different subsystems such as the engine, battery, motor, and air conditioner), and intelligent control, realizes the efficient distribution of the coolant, and is the "transportation hub" of the vehicle thermal management system. Its performance directly affects the overall vehicle energy efficiency, battery life, and driving safety, and has become one of the key technologies especially in new energy vehicles.

[0003] As an important structural component in the integrated module of the vehicle thermal management system, the flow channel plate is in contact with the coolant under long-term high-temperature conditions, and has relatively high requirements for properties such as high-temperature alcoholysis resistance of the material. Moreover, in order to ensure the safety of the heat sources (especially the battery) of new energy vehicles, the thermal management of new energy vehicles is more stringent than that of traditional fuel vehicles.

[0004] A modified composite material based on nylon 66 (also known as PA66) is regarded as a material that can be used for the flow channel plates of hybrid and range-extended new energy vehicles because of its excellent heat distortion temperature and high-temperature tensile properties. However, nylon 66 has a high cost and does not meet the cost reduction requirements of users. If PA6 is used, the water absorption rate and high-temperature alcoholysis resistance performance cannot meet the requirements.

[0005] Currently, there is no low-cost material that can meet the actual use conditions of the heat flow channel plates of new energy vehicles and provide a material with good comprehensive high-temperature alcoholysis resistance, water absorption rate, processing efficiency, cost, and other properties. Summary of the Invention

[0006] In order to solve the technical problems existing in the prior art, the present invention provides a composite material with good high-temperature alcoholysis resistance effect, low water absorption rate, good tensile strength and retention rate performance, high processing efficiency, and low cost, a preparation method thereof, and an application thereof. Specifically, it is achieved through the following technical solutions: The PA / PP composite material for vehicle flow channel plates, by weight, comprises the following components: PA6 35 - 50 PP 20 - 35 Glass fiber 25 - 35 Antioxidant 0.2 - 0.5 Compatibilizer 0.3 - 0.6 The relative viscosity of the PA6 is 2.3 - 2.8; The melt index of the PP is 3 - 8 g / 10min; The compatibilizer is PP-co-MAH (maleic anhydride grafted polypropylene), wherein the MAH content is 40wt% - 60wt%. Preparation method: After weighing and mixing the compatibilizer and PP according to the formula, melt blending and pelletizing are carried out by a twin-screw extruder to obtain a premix; the remaining components except glass fiber are weighed and mixed according to the formula, and are added together with the premix from the main feeding port, and the glass fiber is added from the side feeding port to the twin-screw extruder, and after melt blending and pelletizing, a composite material is obtained.

[0007] Optionally, the PP is homopolymerized PP.

[0008] Optionally, the glass fiber is chopped glass fiber.

[0009] Optionally, the antioxidant is at least two of hindered phenol, phosphite, thioether, polyaromatic amine or hindered amine.

[0010] Optionally, it further includes fatty acid amide lubricants, and the fatty acid amide lubricants include one or more of ethylene bis-fatty acid amide, ethylene bis-stearamide, erucamide, oleamide, stearamide.

[0011] Optionally, it further includes one or more of color powder, nucleating agent, toughening agent, coupling agent.

[0012] This application also provides a preparation method of the foregoing composite material, including the following steps: During the preparation of the premix, the barrel temperature of the twin-screw extruder is 230°C - 265°C, and the main screw rotation speed is 300 - 450 r / min; during the preparation of the final composite material, the barrel temperature of the twin-screw extruder is 180°C - 210°C, and the main screw rotation speed is 300 - 450 r / min.

[0013] This application also provides an application of the foregoing composite material in the flow channel plate of a vehicle thermal management integration module.

[0014] Compared with the prior art, in this application, the relative viscosity of PA6 is 2.4 - 2.8, and the melt index of PP is 3 - 8 g / 10min. By controlling the similar melt viscosity, the mixing effect of PA6 and PP melts is improved, and the tendency of stratification of the two resins caused by fluidity during the injection molding process is prevented.

[0015] In addition, the applicant unexpectedly found that, compared with 3 to 10 parts of the commonly used PP-g-MAH (maleic anhydride grafted polypropylene), the present application uses PP-co-MAH (about one-tenth of the dosage) which is much lower than the dosage of the conventional PP-g-MAH. The special preparation method combined with the formula produces a synergistic effect, and instead improves the long-term high-temperature alcoholysis resistance of the composite material, and the technical effect is difficult to predict. The applicant believes that the possible mechanism is as follows: on the one hand, the selection of the viscosity / melt index of PA6 and PP fully provides the probability of the movement and proximity of the molecular chains of the two. On the other hand, during the process that PP-co-MAH is first physically entangled with the PP chain segment and then reactively blended with PA6, a large amount of ring-opening polymerization occurs between the extremely high content of MAH in PP-co-MAH and the PA6 molecular chain, playing an important compatibilizing role at the interface between the alloy PP and the PA6 molecule. In addition, due to the relatively large interfacial tension of the relatively large number of PA6 molecular chains formed by the reaction polymerization, only a small amount of PP can be wrapped inside, forming small-sized and evenly distributed "island structures", which to a certain extent extends the path of small molecule alcohol intrusion and greatly improves the alcoholysis resistance of the material. In the conventional processing method, PA6 is more likely to undergo a chemical bond reaction with multiple MAH sites on the same PP-co-MAH molecular chain, and the large steric hindrance seriously affects the entanglement of the PP-co-MAH molecular chain and PP, thereby reducing the compatibilization effect.

[0016] In addition, it should be noted that PP-g-MAH, as a commonly used compatibilizer, has a large addition amount, is relatively easy to disperse in industrial production (such as a twin-screw extruder), and has a low cost. PP-co-MAH (maleic anhydride copolymerized polypropylene) is not a component used as a compatibilizer in this field.

[0017] The composite material of the solution of the present application meets the requirements of the long-term high-temperature alcoholysis resistance performance index, and has a low cost, and can better replace the composite material of PA66 and be applied to the flow channel plate of the vehicle thermal management integration module. Description of the Drawings

[0018] Figure 1 It is a scanning electron microscope comparison diagram of etched PP for Example 2 (left) and Comparative Example 2 (right). Detailed Embodiments

[0019] The following elaborates the specific embodiments of the present application in detail through examples. However, the specific implementation of the present application does not limit the technical solution of the present application. Any non-substantive changes such as replacing common technical solutions in the art using the technical solutions described in the embodiments of the present application are within the protection scope of the present application.

[0020] Unless otherwise specified, the technologies used in the following examples are all conventional technologies known to those skilled in the art and do not need to be described in detail; the instruments, equipment, reagents, etc. used, unless otherwise specified in this specification, can be obtained by those skilled in research and technology in the field through public channels.

[0021] In this application, the melt index of PP is measured according to the standard method of GB / T 3682.1-2018.

[0022] In the following specific embodiments, the raw materials used are as follows, but it is not intended to limit the source of the products.

[0023] PA6 has a relative viscosity of 2.4, from Guangdong Xinhui Meida Acrylic Fiber Co., Ltd., M2400; PA6 has a relative viscosity of 2.8, from Guangdong Xinhui Meida Polyamide Co., Ltd., M32800; PA6 has a relative viscosity of 2.0, from Guangdong Xinhui Meida Polyamide Co., Ltd., M2000; PP has a melt index of 3 g / 10 min, from Sinopec Zhenhai Refining & Chemical Company, T03; PP has a melt index of 8 g / 10 min, from Yanshan Petrochemical, K1008; PP has a melt index of 16 g / 10 min, from Donghua Energy (Ningbo) New Materials Co., Ltd., Y16; Glass fiber: from Chongqing International Composite Materials Co., Ltd., ECS301HP-3-H; PP-co-MAH (maleic anhydride copolymerized polypropylene): from Mitsubishi Chemical (Shanghai) Co., Ltd. with a MAH content of 50 wt%, Diacarna 30M; PP-g-MAH (maleic anhydride grafted polypropylene): with a MAH grafting rate of 1.03 wt%, from Jiayirong Compatibilizer Jiangsu Co., Ltd., Fine-Blend CMG5701; Antioxidant 1010: from BASF; Antioxidant 168: from Lian An Long; Lubricant: ethylene bisstearamide (EBS), from Guangzhou Fenghua Chemical Technology Co., Ltd.

[0024] The preparation method of the composite material is as follows. It should be noted that the method of screw extrusion granulation is a conventional means used by those skilled in the art in the plastic processing process and does not need to be elaborated.

[0025] Except for Comparative Example 5, the preparation methods of each example and comparative example are as follows: The preparation methods of Examples 1-7 and Comparative Example 6 for the composite material are as follows: After weighing and mixing the compatibilizer and PP according to the formula, they were melt-blended and pelletized by a twin-screw extruder to obtain a premix. Among them, the barrel temperature of the twin-screw extruder was 180°C to 210°C, and the main screw speed was 300 to 450 r / min; the remaining components except glass fiber were weighed and mixed according to the formula, and then added to the main feed port together with the premix. Glass fiber was added to the twin-screw extruder from the side feed port, and after melt-blending and pelletizing, a composite material was obtained. Among them, the barrel temperature of the twin-screw extruder was 230°C to 265°C, and the main screw speed was 300 to 450 r / min.

[0026] The preparation methods used in Comparative Examples 1 to 5 were as follows: The other components except glass fiber were weighed and mixed according to the formula, added from the main feed port, and glass fiber was added to the twin-screw extruder from the side feed port. After melt-blending and pelletizing, a composite material was obtained. Among them, the barrel temperature of the twin-screw extruder was 230°C to 265°C, and the main screw speed was 300 to 450 r / min. It should be noted that under normal circumstances, when using PP-g-MAH as a compatibilizer, those skilled in the art can meet the compatibilization requirements by using the direct addition method.

[0027] The performance characterization and testing methods of the composite materials were as follows: Preparation of test specimens: The pellets of each example and comparative example were dried in an oven at 80 - 100°C for 4 - 6 h, and then injection-molded into standard specimens according to the requirements of each standard for relevant performance testing, with the mold temperature being 60 - 100°C.

[0028] Tensile strength, MPa: ISO 527-1, 5 mm / min, 1A type specimen.

[0029] Alcoholysis test: The sample to be treated was placed in a solution of water:ethylene glycol 1:1, and soaked at 120°C for different times (0 h, 1000 h). After taking out the specimen, it was rinsed with tap water and then dried for 3 h, and then the performance was evaluated.

[0030] The tensile strength retention rate is the change rate of the tensile strength of the material before and after the alcoholysis experiment, and the calculation method is: Tensile strength retention rate = Tensile strength after alcoholysis of the material / Tensile strength before alcoholysis of the material × 100%.

[0031] Water absorption: According to ISO 62 standard, the sample to be tested was placed under the conditions of a temperature of 75°C and a humidity of 75%RH for different times (0 h (dry state), 24 h, 72 h, 168 h, 240 h) for testing.

[0032] Delamination: Visually observe whether there is delamination in the sample.

[0033] The components and properties of the examples and comparative examples are shown in Table 1 respectively, and the unit of each component in the table is parts by weight.

[0034] Table 1 Component and Performance Test Data of Examples 1 - 7 and Comparative Examples 1 - 6

[0035] The data in Table 1 show that when comparing Example 2 with Comparative Example 2, using 0.5 parts of PP - co - MAH (maleic anhydride copolymerized polypropylene) instead of 5 parts of PP - g - MAH (maleic anhydride grafted polypropylene), after treatment at 75°C and 75% RH for 240 h, the saturated water content is lower. After alcoholysis of the coolant at 120°C for 1000 h, the tensile strength and tensile strength retention rate are higher, above 50 MPa, meeting the actual use requirements. Further, the lower water content of the material and the higher welding strength are more conducive to the subsequent welding process of the parts and improve the product quality.

[0036] In the formulation systems of Comparative Examples 3 and 4, although 0.5 parts of PP - co - MAH were also used, the samples showed a layering phenomenon and poor compatibility effect.

[0037] When comparing Comparative Example 5 with Example 2, the preparation method of the conventional directly blended composite material has poor water content and alcoholysis resistance performance, and layering also occurs, unable to meet the requirements.

[0038] The test specimen of Example 2 was quenched and broken with liquid nitrogen, and the PP phase was etched with xylene, and the cross - sectional micro - morphology was observed by scanning electron microscopy, as shown in Figure 1 the left figure. The micro - morphology diagram of Comparative Example 2 after the same treatment is as shown in Figure 1 the right figure. It can be seen from the figure that the formulation of Example 2 makes the distribution of PP in the system more uniform and the size relatively smaller, indicating better compatibility of the system.

[0039] Finally, it should be noted that the specific embodiments described in the present invention are only illustrative of the spirit of the present invention rather than limiting the protection scope of the present invention. For those of ordinary skill in the art, it is easy to modify the technical solution or make equivalent substitutions without departing from the technical idea and scope of the spirit of the present invention.

Claims

1. PA / PP composite material for vehicle flow channel plate, characterized in that By weight, it comprises the following components: PA6 35 - 50 PP 20 ~ 35 Glass fiber 25 - 35 Antioxidant 0.2 - 0.5 Compatibilizer 0.3 - 0.6 The relative viscosity of the PA6 is 2.3 - 2.8; The melt index of PP is 3 - 8 g / 10min; The compatibilizer is PP - co - MAH, wherein the MAH content is 40wt% - 60wt%; Preparation method: After weighing and mixing the compatibilizer and PP according to the formula, melt - blend and pelletize them through a twin - screw extruder to obtain a premix; Weigh and mix the remaining components except glass fiber according to the formula, and add them together with the premix from the main feed port, and add glass fiber from the side feed port to the twin - screw extruder, then melt - blend and pelletize to obtain the composite material.

2. The composite material according to claim 1, wherein The PP is homopolymer PP.

3. The composite material according to claim 1, characterized in that, The glass fiber is chopped glass fiber.

4. The composite material according to claim 1, characterized in that, The antioxidant is at least two of hindered phenol, phosphite, thioether, polyaromatic amine or hindered amine.

5. The composite material according to claim 1, characterized in that, It also includes fatty acid amide lubricants, and the fatty acid amide lubricants include one or more of ethylene bis - fatty acid amide, ethylene bis - stearamide, erucamide, oleamide, stearamide.

6. The composite material according to claim 1, characterized in that, It also includes one or more of color powder, nucleating agent, toughening agent, coupling agent.

7. The preparation method of the composite material according to any one of claims 1 - 6: During the preparation of the premix, the barrel temperature of the twin - screw extruder is 230°C - 265°C, and the main screw speed is 300 - 450 r / min; During the preparation of the final composite material, the barrel temperature of the twin - screw extruder is 180°C - 210°C, and the main screw speed is 300 - 450 r / min.

8. Use of the composite material according to any one of claims 1 to 6, characterized in that, It is applied in the flow channel plate of the vehicle thermal management integration module.

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