Injection molding part for auxiliary instrument assembly of vehicle, preparation method and vehicle

Abstract

The invention provides an injection molding part for a vehicle auxiliary instrument assembly, a preparation method and a vehicle. The injection molding part provided by the invention is prepared from a polypropylene composite material, wherein the polypropylene composite material at least comprises the following components in parts by weight: 30-35 parts of high-crystallinity co-polypropylene; 25 to 30 parts of homo-polypropylene; 25 to 30 parts of glass fiber; 3-5 parts of a toughening agent, 2-3 parts of a nucleating agent and 0.2-0.4 part of crystal whiskers; wherein the specification of the glass fiber is 2400 tex. The polypropylene composite material prepared according to the proportion can realize the light weight of the auxiliary instrument.

Description

Technical Field

[0001] The present application relates to the field of vehicles, and more specifically, to an injection molded part for a vehicle auxiliary instrument assembly, a preparation method thereof, and a vehicle. Background Art

[0002] With the development trend of lightweight automobiles, injection molded parts made of polypropylene composite materials have been widely used in automobile parts. Thermoplastic polypropylene has good processability and recyclable properties, so its products can be seen everywhere in our daily life. However, due to the mechanical properties of thermoplastics such as strength and hardness, there is still a certain gap between them and metal materials, so thermoplastic products are generally used as non-structural parts and are difficult to bear loads as structural parts.

[0003] With the compounding of thermoplastic polypropylene and glass fiber, its hardness and strength are greatly enhanced. Compared with unmodified thermoplastic polypropylene, the tensile strength of the reinforced composite material is increased by about 2 times, the flexural strength is increased by more than 1.4 times, and the flexural modulus is increased by about 2.2 times; at the same time, the dimensional stability is optimized, the thermal deformation is reduced, the shrinkage rate is reduced, the material hardness is increased, and the water absorption is reduced; and the thermal stability is improved, and its heat-resistant temperature can be greatly increased compared with unmodified polypropylene, and it can be used in products with high temperature resistance and strength requirements.

[0004] With the gradual increase in the demand for lightweighting, how to reduce the density of materials while ensuring the performance and cost of the product, and achieve good comprehensive performance that meets product needs, low-density and lightweight polypropylene composite materials have become the key research direction of major scientific research institutes. Summary of the invention

[0005] The present application provides an injection molded part for a vehicle auxiliary instrument assembly, a preparation method, and a vehicle, which can achieve lightweighting of the auxiliary instrument.

[0006] Specifically, the present application is implemented through the following technical solutions:

[0007] One aspect of the present application provides an injection molded part for a vehicle auxiliary instrument assembly, wherein the injection molded part is made of a polypropylene composite material, and the polypropylene composite material at least includes the following components counted in parts by weight:

[0008] 30-35 parts of high crystalline copolymer polypropylene;

[0009] Homopolymer polypropylene 25-30 parts;

[0010] Glass fiber 25-30 parts;

[0011] 3-5 parts of toughening agent, 2-3 parts of nucleating agent, 0.2-0.4 parts of whiskers;

[0012] The specification of the glass fiber is 2400tex.

[0013] Optionally, the polypropylene composite material further comprises the following components counted in parts by weight:

[0014] Antioxidant 0.1-0.3 parts, lubricant 0.1-0.3 parts, scratch resistant agent 0.1-0.3 parts, light stabilizer 0.05-0.15 parts.

[0015] Optionally, the toughening agent is selected from one or more of ethylene propylene diene monomer rubber (EPDM), ethylene propylene rubber (EPR), thermoplastic elastomer (SEBS), and polyolefin elastomer (POE).

[0016] Optionally, the side portion of the injection molded part includes a first side wall and a second side wall that are arranged opposite to each other, the first side wall is used to fix parts inside the injection molded part, a surface of the first side wall is provided with a first reinforcing rib that protrudes outward, and the first reinforcing rib is distributed in a polygonal shape, and along the height direction of the injection molded part, the first side wall includes a first area, a second area, and a third area that are arranged in sequence up and down, and the number of parts fixed in the second area is greater than the number of parts fixed in the first area, and greater than the number of parts fixed in the third area;

[0017] The first reinforcing ribs in the first area are distributed as a plurality of first polygons, the first reinforcing ribs in the second area are distributed as a plurality of second polygons, and the first reinforcing ribs in the third area are distributed as a plurality of third polygons, wherein the number of sides of the second polygons is greater than the number of sides of the first polygons and greater than the number of sides of the third polygons.

[0018] Optionally, the surface of the second side wall is provided with second reinforcing ribs protruding outward, and the second reinforcing ribs are distributed in the form of a plurality of regular hexagons on the second side wall.

[0019] Optionally, the side portion of the injection molded part also includes a third side wall, the third side wall connects the first side wall and the second side wall, the third side wall is provided with a drawer opening, and the third side wall is also provided with a third reinforcing rib, the third reinforcing rib extends toward the interior of the injection molded part, and the cross-section of the third reinforcing rib is a double H-shape.

[0020] Optionally, the injection molded part further comprises a top wall, three sides of which are respectively connected to the first side wall, the second side wall and the third side wall, and along the thickness direction of the injection molded part, the length of the top wall is less than the length of the first side wall;

[0021] Along the thickness direction of the injection molded part, the first region includes a first sub-region and a second sub-region distributed side by side front and back, and the side length of the top wall includes the side length of the first sub-region and part of the side length of the second sub-region, the reinforcement ribs of the first sub-region are distributed in a plurality of squares, and the reinforcement ribs of the second sub-region are distributed in a plurality of rectangles.

[0022] Optionally, the top wall is provided with at least one first protrusion facing the inside of the injection molded part, and at least one second protrusion facing the outside of the injection molded part; and / or

[0023] The top wall is provided with a plurality of weight-reducing holes.

[0024] Another aspect of the present application provides a method for preparing an injection molded part for a vehicle auxiliary instrument assembly, comprising:

[0025] The raw materials are mixed to form a polypropylene composite material, wherein the raw materials include: 30-35 parts of high crystalline copolymer polypropylene, 25-30 parts of homopolymer polypropylene, 25-30 parts of glass fiber, 3-5 parts of toughening agent, 2-3 parts of nucleating agent, 0.2-0.4 parts of whisker, 0.1-0.3 parts of antioxidant, 0.1-0.3 parts of lubricant, 0.1-0.3 parts of scratch resistance agent, 0.05-0.15 parts of light stabilizer, wherein the specification of the glass fiber is 2400tex;

[0026] The molten polypropylene composite material is integrally injection-molded into the injection molded part through an injection mold.

[0027] Optionally, in the step of integrally injecting the molten polypropylene composite material into the injection molded part through an injection mold, the temperature of the injection mold is 50-60°C, the melt temperature is 230-240°C, the injection speed is 40-60mm / s, the back pressure is 165-170bar, and the holding pressure is 30-42MPa.

[0028] Another aspect of the present application provides a vehicle, comprising the injection molded part described in any one of the above items.

[0029] The present application provides an injection molded part for a vehicle auxiliary instrument assembly, a preparation method, and a vehicle. The glass fiber has a relatively fine specification and is a composite material made according to the ratio of the present application. In fact, polyethylene material (PVE) is added to the glass fiber composite polypropylene material to plasticize the composite material, thereby changing the ratio of the raw materials. In addition, the glass fiber has a relatively fine specification, and the polypropylene composite material finally made has a relatively small density as measured by experiments, which can achieve lightweight materials. Products made of the modified polypropylene composite material of the present application are more than 7% lighter than traditional materials, which can achieve lightweight products. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of a secondary instrument assembly showing an exemplary embodiment;

[0031] Figure 2 is a schematic diagram of an injection molded part shown in an exemplary embodiment of the present application;

[0032] Figure 3 is a left view of an injection molded part shown in an exemplary embodiment of the present application;

[0033] Figure 4 is a right side view of an injection molded part shown in an exemplary embodiment of the present application;

[0034] Figure 5 is a front view of an injection molded part shown in an exemplary embodiment of the present application;

[0035] Figure 6 is a top view of an injection molded part shown in an exemplary embodiment of the present application;

[0036] Figure 7 It is a flow chart of a method for preparing injection molded parts shown in an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0037] Here, the technical solutions in the embodiments (or "implementations") of the present application will be described clearly and completely in conjunction with the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0038] If there are terms involving directional indications or positional relationships in the embodiments of the present application (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings); if the specific posture changes, the directional indication or positional relationship will also change accordingly. In addition, the terms "first", "second", etc. involved in the embodiments of the present application are only used for the purpose of convenience of description and cannot be understood as indicating or implying relative importance.

[0039] At present, the main types of automotive interior and exterior brackets are made of 30% glass fiber and polypropylene resin, with a density of more than 1.15g / cm3. Composite materials have a high density. With the development trend of lightweight automobiles, combined with Figure 1 and Figure 2 The present application provides an injection molded part 100 for a vehicle auxiliary instrument assembly. The vehicle auxiliary instrument is composed of the injection molded part 100 and a skin 200 . The injection molded part 100 is also the skeleton of the auxiliary instrument, and the skin 200 surrounds the outside of the injection molded part 100 .

[0040] The injection molded part 100 is made of a polypropylene composite material, which is mainly a composite of glass fiber and polypropylene. The polypropylene composite material at least includes the following components counted by weight: 30-35 parts of high-crystalline copolymer polypropylene, such as 30 parts, 32 parts, 35 parts, etc.; 25-30 parts of homopolymer polypropylene, such as 25 parts, 28 parts, 30 parts, etc.; 25-30 parts of glass fiber, such as 25 parts, 26 parts, 30 parts, etc.; and 3-5 parts of toughening agent, such as 3 parts, 4 parts, 5 parts, etc. Nucleating agent 2-3 parts, such as 2 parts, 2.5 parts, 3 parts, etc. Whisker 0.2-0.4 parts, such as 0.2 parts, 0.3 parts, 0.4 parts, etc. The specification of the glass fiber is 2400tex.

[0041] Wherein, the whisker can be magnesium oxysulfide whisker, which can form a good interface with the polypropylene matrix, can more effectively transfer stress, prevent the expansion of cracks, and thus improve the overall strength of the material. An exemplary whisker can be 152-type magnesium oxysulfide whisker. A nucleating agent can accelerate the crystallization rate, and an exemplary nucleating agent can be maleic anhydride.

[0042] This application actually adds polyethylene material (PVE) to glass fiber composite polypropylene material to plasticize the composite material, thereby changing the ratio of the raw materials. In addition, the specifications of the glass fiber are relatively fine, and the final polypropylene composite material has a relatively low density after experimental measurement, which can achieve lightweight materials. In addition, the products made of the modified polypropylene composite material of this application are more than 7% lighter than traditional materials, which can achieve lightweight products.

[0043] In one embodiment, the polypropylene composite material further includes the following components counted by weight: 0.1-0.3 parts of antioxidants, 0.1-0.3 parts of lubricants, 0.1-0.3 parts of scratch resistant agents, and 0.05-0.15 parts of light stabilizers. Specific components may be 0.2 parts of antioxidants, 0.2 parts of lubricants, 0.2 parts of scratch resistant agents, and 0.1 parts of light stabilizers. Light stabilizers can improve the light stability of composite materials, and an exemplary light stabilizer may be a light stabilizer 770 group. The antioxidant is 1010 antioxidant. Lubricants are conducive to the mixing of various raw materials. And scratch resistant agents can improve the scratch resistance of materials and other effects. Exemplarily, lubricants may include at least one of polyethylene wax, polypropylene wax, etc. The scratch resistant agent may include at least one of tetraboride, nano zirconium oxide, erucic acid amide, and oleic acid amide, etc.

[0044] In another embodiment, the toughening agent is selected from one or more of ethylene propylene diene monomer rubber (EPDM), ethylene propylene rubber (EPR), thermoplastic elastomer (SEBS), and polyolefin elastomer (POE). The toughening agent can improve the toughness of the composite material, improve the crack resistance, and improve the mechanical strength of the manufactured polypropylene composite material.

[0045] In one embodiment, in combination Figure 2 and Figure 3 The side of the injection molded part 100 includes a first side wall 110 and a second side wall 120 that are arranged opposite to each other. The first side wall 110 is used to fix the parts inside the injection molded part 100. The surface of the first side wall 110 is provided with a first reinforcing rib that protrudes outward, and the first reinforcing rib is distributed in a polygonal shape. Along the height direction z of the injection molded part 100, the first side wall 110 includes a first area 111, a second area 112, and a third area 113 that are arranged in sequence up and down. The number of parts fixed in the second area 112 is greater than the number of parts fixed in the first area 111, and greater than the number of parts fixed in the third area 113.

[0046] The first reinforcing ribs of the first area 111 are distributed in a plurality of first polygons 20, the first reinforcing ribs of the second area 112 are distributed in a plurality of second polygons 30, and the first reinforcing ribs of the third area are distributed in a plurality of third polygons 40. The number of sides of the second polygon 30 is greater than the number of sides of the first polygon 20, and greater than the number of sides of the third polygon 40. And the uniform distribution of the sides of the second polygon 30 is also greater than that of the first polygon 20 and the third polygon 40. The structural strength is related to the symmetry and uniformity of the structure. Structural shapes with better symmetry and uniformity can usually disperse and resist external forces more effectively. Therefore, the structural strength of the second polygon 30 of the present application is greater than that of the first polygon 20 and the third polygon 40.

[0047] There are many fixing points of the parts such as the bracket and the wiring harness inside the auxiliary instrument in the second area 112, so the second area 112 bears a greater load and requires greater strength. Therefore, in this embodiment, the first reinforcing ribs in the second area 112 are arranged to be distributed as a plurality of second polygons 30. The first reinforcing ribs of different shapes are divided into three areas to meet the strength requirements of different areas. According to the installation conditions of parts at different positions, when the auxiliary instrument is assembled inside the vehicle, the corresponding in-vehicle environment of different areas, the shapes of different side walls, the brackets inside the injection molded part 100, and the fixing positions of the wiring harness all need to be considered, and the shape distribution of the first reinforcing ribs is designed in combination with the strength requirements of each location.

[0048] In one embodiment, the first polygon 20 is a quadrilateral, which includes a square and a rectangle. The second polygon 30 is a regular hexagon, that is, a honeycomb distribution. The third polygon 40 is a rectangle.

[0049] It should be noted that the regular hexagon of the second polygon 30 will adapt to the outline of the second area 112, presenting a partial structure or deformation of the regular hexagon. The structural strength of the regular hexagon is greater than that of the quadrilateral and the rectangle.

[0050] The wall thickness of the injection molded part 100 can be designed to be 2.5-3.0mm, such as 2.5mm, 2.8mm, 3.0mm, etc. The height of the first reinforcing rib protruding from the surface of the first side wall 110 is 2mm. The first area 111 faces the inside of the injection molded part (not shown in the figure), and a 1*3mm rectangular weight-reducing hole and a 1*2mm oblong weight-reducing hole can be designed. Under the requirement of ensuring the strength of the first area 111, the weight-reducing hole is designed to meet the demand for lightweight. At the same time, the first area 111 also includes two first mounting and fixing bosses 51, and the surface of the mounting and fixing bosses is provided with a groove-shaped fixing hole for fixing and connecting with the skin 200 of the auxiliary instrument through a threaded connector. The threaded connector can be an M6 bolt. The mounting and fixing boss protrudes outward from the surface of the first side wall 110, and the height is greater than the height of the first reinforcing rib protrusion. The second area 112 is provided with a second mounting and fixing boss 52, and the third area 113 is provided with a third mounting and fixing boss 53. The number of mounting and fixing bosses in different areas is related to the shape of the epidermis 200 corresponding to the first side wall 110. More mounting and fixing bosses are set in the corresponding areas of the epidermis 200 with larger surface area and heavier mass to ensure the stability of the fixed mounting surface between the epidermis 200 and the first side wall 110. Specifically, the height of the first mounting and fixing boss 51 located in the first area 111 is 10mm-15mm, and the width is 5mm-10mm. The height of the second mounting and fixing boss 52 located in the second area 112 is 9mm-12mm, and the width is 3mm-8mm. The height of the third mounting and fixing boss 53 located in the third area 113 is 10mm-12mm, and the width is 5mm-8mm. The different heights are related to the distance between different areas of the epidermis 200 and the side wall area of ​​the injection molded part.

[0051] Due to the limitation of space design, the second area 112 can be partially cut out of the regular hexagon to match the outline of the second area 112 and the outline of the mounting boss and other parts. The rectangular first reinforcing ribs of the third area 113 are mostly composed of 3mm*4mm rectangles 41, but based on the limitation of the space design of the third area 113 structure, a partial structure 42 of 1*1 triangles with two corners removed from the rectangle can be designed. Or other first reinforcing rib shapes that are deformed on the basis of the 3mm*4mm rectangle 41, in order to make the first reinforcing ribs in the shape of 3mm*4mm rectangles 41, more and more reasonable distribution can be made in the third area.

[0052] In one embodiment, in combination Figure 4The surface of the second side wall 120 is provided with a second reinforcing rib protruding outward, and the height of the second reinforcing rib protruding can be 2mm. The second reinforcing ribs of the second side wall 120 are distributed in a plurality of regular hexagons. There are fewer parts, wiring harnesses or brackets inside the auxiliary instrument distributed near the second side wall 120, and fewer installation points need to be designed, so the second side wall 120 does not need a complex second reinforcing rib structure design to meet the strength requirements.

[0053] The second side wall 120 is provided with four fourth mounting and fixing bosses 54, with a height of 9mm-12mm and a width of 3mm-8mm. Due to space design limitations, the second reinforcing ribs of the second side wall 120 can be distributed by cutting off a part of the structure on the basis of a regular hexagon to match the contour of the second side wall 120 and the contour of the mounting and fixing bosses and other parts.

[0054] In one embodiment, reference Figure 2 and Figure 5 The side wall of the injection molded part 100 also includes a third side wall 130, which connects the first side wall 110 and the second side wall 120. The third side wall 130 is provided with a drawer opening 131, and the third side wall 130 is also provided with a third reinforcing rib 132, the third reinforcing rib 132 extends toward the inside of the injection molded part, and the cross-section of the third reinforcing rib 132 presents a double H shape, specifically two Hs are horizontally distributed and connected to each other. The H-shaped structure can disperse stress more effectively. When external force acts on the structure, the double H-shaped reinforcing ribs can evenly transfer stress to the entire structure, thereby avoiding damage caused by excessive local stress. Since the third side wall 130 is provided with a drawer opening 131, the structure is relatively weak. The third reinforcing rib 132 can strengthen the overall strength of the third side wall 130 on the one hand, and can also strengthen the strength of the drawer opening 131 on the other hand.

[0055] The third reinforcing rib 132 has a width of 40 mm to 60 mm and a length of 150 mm to 200 mm, and a length extending toward the interior of the injection molded part is 150 mm to 200 mm.

[0056] In one embodiment, in combination Figure 6 The injection molded part 100 also includes a top wall 140, which is the table top of the auxiliary instrument assembly. The three sides of the top wall 140 are respectively connected to the first side wall 110, the second side wall 120 and the third side wall 130. Along the thickness direction y of the injection molded part, the length of the top wall 140 is less than the length of the first side wall 110. From the top view, the top wall and the first side wall 110 and the second side wall 120 are The user usually chooses to place cups, keys, mobile phones and other items on the countertop, so the countertop also needs strong structural strength.

[0057] Along the thickness direction y of the injection molded part 100, the first region 111 includes a first sub-region 1111 and a second sub-region 1112 that are arranged side by side in the front and back directions, and the side length of the top wall 140 includes the side length of the first sub-region 1111 and the side length of part of the second sub-region 1112. The first reinforcing ribs of the first sub-region 1111 are distributed in a plurality of squares, and the first reinforcing ribs of the second sub-region 1112 are distributed in a plurality of rectangles. The structural strength of the square is greater than that of the rectangle, and the rectangle can be lightweight relative to the square.

[0058] The table top of the injection molded part 100 is located above the first sub-area 1111, and users generally place items such as mobile phones and keys on the table top. The entire first sub-area 1111 and part of the second sub-area 1112 serve as side walls to support the top wall 140. Therefore, the first sub-area 1111 requires greater structural strength than the second sub-area 1112. Therefore, the first reinforcing rib of the first sub-area 1111 is designed to be a square. Since the second sub-area 1112 does not require greater strength, it can be designed as a rectangular first reinforcing rib to meet the needs of partial lightweighting. The square is a 5mm×5mm square 21, and the rectangle can include a 5mm×8mm, 5mm×3mm rectangle 22. For some local structures with less force, it can be designed as a pentagonal grid structure formed by removing the 1×1 triangle from the corner of the 8×3 rectangular grid.

[0059] In one embodiment, the top wall 140 is provided with at least one first protrusion 141 facing the inside of the injection molded part 100, and at least one second protrusion 142 facing the outside of the injection molded part 100. The first protrusion 141 and the second protrusion 142 are provided to increase the area of ​​the table top, that is, the force-bearing area of ​​the table top. Compared with the table top with a completely planar structure, the table top of this embodiment can withstand a greater collision strength along the thickness direction y of the auxiliary instrument. The second protrusions 142 are distributed on both sides of the first protrusion 141, and the top wall presents a "concave" shape. On the surface of the second protrusion 142, in order to ensure the installation of the epidermis 200, a fifth mounting and fixing boss 55 can be provided. On both sides of the first protrusion 141, the second protrusion 142 on one side is designed as 6 fifth mounting and fixing bosses 55, and the second protrusion 142 on the other side is designed as 3 fifth mounting and fixing bosses 55. In addition, multiple first protrusions 141 and second protrusions 142 can also be provided.

[0060] The top wall 140 is provided with a plurality of weight-reducing holes, which can achieve lightness while meeting the required strength of the table. The size of the weight-reducing holes is 6mm*8mm, and the plurality of weight-reducing holes are arranged in a 6*3 pattern, with 18 holes provided.

[0061] The structural design of the injection molded part 100 is based on the mechanical properties of the polypropylene composite material, the force analysis of each position of the auxiliary instrument assembly, the stiffness and strength analysis, and the consideration of lightweight.

[0062] refer to Figure 7 The present application also provides a method for preparing an injection molded part for a vehicle auxiliary instrument assembly, comprising:

[0063] S100, mixing raw materials to form a polypropylene composite material, wherein the raw materials include: 30-35 parts of high crystalline copolymer polypropylene, 25-30 parts of homopolymer polypropylene, 25-30 parts of glass fiber, 3-5 parts of toughening agent, 2-3 parts of nucleating agent, 0.2-0.4 parts of whisker, 0.1-0.3 parts of antioxidant, 0.1-0.3 parts of lubricant, 0.1-0.3 parts of anti-scratch agent, 0.05-0.15 parts of light stabilizer, wherein the specification of the glass fiber is 2400tex.

[0064] S200, integrally injecting the molten polypropylene composite material into the injection molded part through an injection mold.

[0065] The specific step S100 may include, firstly, weighing the raw materials according to the ingredient formula, mixing the high crystalline copolymer polypropylene, homopolymer polypropylene, toughening agent, nucleating agent and other related additives in a high-speed mixer, then adding the mixture into the extruder for plasticization and mixing, the melt after sufficient mixing enters a special die, and the raw glass fiber will pass through the special die, and complete dispersion, infiltration and melt wrapping in the special die. So that each glass fiber is compounded with polypropylene. Then, under the action of traction, it is cooled and shaped through a die and cut to form a blend, extrusion and granulation.

[0066] The extruder temperature is set between 120 and 280°C according to product performance requirements, the speed is 450r / min, the injection temperature is 190-210°C, the injection pressure is 30MPa, and the screw speed is set to 359r / min. The extruded pellets are dried at 85°C for 2h.

[0067] The above experimental process can prepare a glass fiber reinforced polypropylene composite material that has strength and stiffness that meet the performance requirements of the auxiliary instrument assembly and is low-cost and lightweight.

[0068] Reinforcement ribs and weight-reducing holes of different shapes and numbers are designed at different positions. The shape of the injection molded part is determined through joint analysis of the material and structure, and then injection molding is performed.

[0069] Therefore, the injection molded parts of the vehicle auxiliary instrument assembly manufactured in the present application can meet the design requirements such as modality, lightness, and stiffness, and achieve lightweight.

[0070] In one embodiment, in the step of integrally injecting the molten polypropylene composite material into the injection molded part through an injection mold, the temperature of the injection mold is 50-60° C., the melt temperature is 230-240° C., the injection speed is 40-60 mm / s, the back pressure is 165-170 bar, and the holding pressure is 30-42 MPa. The injection speed refers to the moving speed of the screw or plunger during injection.

[0071] The specific injection molding process is to add the raw materials into the barrel of the injection molding machine, and perform injection molding according to the above-mentioned process parameters. The back pressure of the present application is 165-170bar and the holding pressure is 30-42MPa, which can realize the rapid filling of the mixture into the mold. The use of the process parameters of the present application has a great impact on the filling of the plastic melt, significantly reducing defects such as weld lines and warping, and the product obtained by injection molding has high apparent quality, no appearance flow marks, high tensile strength and tensile modulus. In addition, the injection molding speed does not affect the product quality as much as the melt temperature and mold temperature, but it will directly affect the injection molding cycle. In order to improve the injection molding efficiency and reduce the injection molding cycle, the injection molding speed needs to be reasonably optimized.

[0072] Increasing the mold temperature can effectively reduce the internal stress and orientation of the product, and improve the supercooling of the mold, which is beneficial to improving the surface quality of the product. However, the mold temperature cannot be too high, which will reduce the impact strength in the streamline direction and increase the shrinkage rate.

[0073] Increasing the melt temperature is beneficial to the fluidity of the melt and can reduce the shrinkage of the product, but too high a temperature is not desirable. When the melt temperature approaches the upper limit of the injection molding temperature, it is very easy to produce more gas, causing the plastic to have defects such as bubbles, voids, and discoloration.

[0074] Injection speed, back pressure, and holding pressure all have some improvement on the shrinkage and warpage of the product, but not significantly. The main reason is that when the injection time and cooling time reach a certain time, the melt is fully solidified, reaches a sufficiently large rigidity, and tends to a constant value, and the shrinkage rate gradually tends to be stable.

[0075] Table 1 below shows the preparation method of the injection molded part for the vehicle auxiliary instrument assembly of the present application, and the properties of the injection molded parts obtained by using different process parameters.

[0076]

[0077] Table 1

[0078] The first column shows the process parameters used in the process of preparing auxiliary instruments using traditional polypropylene composite materials. The second to sixth columns are prepared using the polypropylene composite materials of the present application, with different process parameters used for the injection molded parts provided by the present application. According to Table 1, the appearance of the products in the second to sixth columns is significantly improved compared to the first column, which shows that the composite materials provided by the present application can be used to make injection molded parts with better appearance quality. The fifth and sixth columns can obtain products with fewer or no shrinkage marks, which shows that suitable process parameters can meet the requirements of product appearance.

[0079] The following are examples of the present application:

[0080] Example 1

[0081] First, weigh the raw materials according to the following mass ratio: 32 parts of high crystalline copolymer polypropylene, 28 parts of homopolypropylene, 26 parts of glass fiber, 4 parts of toughening agent ethylene propylene diene monomer rubber (EPDM), 2.5 parts of nucleating agent maleic anhydride, 0.3 parts of 152 type magnesium oxysulfide whisker, 0.2 parts of 1010 antioxidant, 0.2 parts of lubricant polyethylene wax, 0.2 parts of scratch resistant agent tetraboride, and 0.1 parts of light stabilizer 770 group.

[0082] Secondly, the raw materials are mixed evenly in a high-speed mixer, and then the mixture is added to the extruder for plasticization and mixing. The fully mixed melt enters a special die, and the continuous glass fiber will also pass through the special die, where it will be dispersed, infiltrated and wrapped with the melt. Then, it is cooled and shaped through the die under traction and cut to form a blend and extrusion granulation. The extruder is set at an extrusion temperature of 200°C, a speed of 450r / min, an injection temperature of 190°C, an injection pressure of 30MPa, and a screw speed of 359r / min. The extruded pellets are dried at 85°C for 2h. Finally, a polypropylene composite material is obtained. After testing, the density of the polypropylene composite is 1.05g / cm 3 .

[0083] Example 2

[0084] First, weigh the raw materials according to the following mass ratio: 30 parts of high crystalline copolymer polypropylene, 25 parts of homopolypropylene, 25 parts of glass fiber, 3 parts of toughening agent ethylene propylene diene monomer rubber (EPDM), 2 parts of nucleating agent maleic anhydride, 0.2 parts of 152 type magnesium oxysulfide whisker, 0.1 parts of 1010 antioxidant, 0.1 parts of lubricant polyethylene wax, 0.1 parts of scratch resistant agent tetraboride, and 0.05 parts of light stabilizer 770 group.

[0085] Secondly, the raw materials are mixed evenly in a high-speed mixer, and then the mixture is added to the extruder for plasticization and mixing. The fully mixed melt enters a special die, and the continuous glass fiber will also pass through the special die, where it is dispersed, infiltrated and wrapped with the melt, and then cooled and shaped through the die under traction and cut to form a blend, extrusion and granulation. The extruder is set at an extrusion temperature of 200°C, a speed of 450r / min, an injection temperature of 190°C, an injection pressure of 30MPa, and a screw speed of 359r / min. The extruded pellets are dried at 85°C for 2h. Finally, a polypropylene composite material is obtained. After testing, the polypropylene composite has a density of 1.03g / cm3.

[0086] Example 3

[0087] First, weigh the raw materials according to the following mass ratio: 35 parts of high crystalline copolymer polypropylene, 30 parts of homopolymer polypropylene, 30 parts of glass fiber, 5 parts of toughening agent ethylene propylene diene monomer rubber (EPDM), 3 parts of nucleating agent maleic anhydride, 0.4 parts of 152 type magnesium oxysulfide whisker, 0.3 parts of 1010 antioxidant, 0.3 parts of lubricant polyethylene wax, 0.3 parts of scratch resistant agent tetraboride, and 0.15 parts of light stabilizer 770 group.

[0088] Secondly, the raw materials are mixed evenly in a high-speed mixer, and then the mixture is added to the extruder for plasticization and mixing. The fully mixed melt enters a special die, and the continuous glass fiber will also pass through the special die, where it is dispersed, infiltrated and wrapped with the melt, and then cooled and shaped through the die under traction and cut to form a blend, extrusion and granulation. The extruder is set at an extrusion temperature of 200°C, a speed of 450r / min, an injection temperature of 190°C, an injection pressure of 30MPa, and a screw speed of 359r / min. The extruded pellets are dried at 85°C for 2h. Finally, a polypropylene composite material is obtained. After testing, the polypropylene composite has a density of 1.07g / cm3.

[0089] According to the analysis of the above embodiment, it is known that the conventional 30% glass fiber and polypropylene resin are compounded to form a polypropylene composite material. After testing, the density of the polypropylene composite material is measured to be 1.15g / cm3. The density of the polypropylene composite material prepared in the embodiment of the present application is 1.03g / cm 3 -1.07g / cm 3 The density is lower than that of the traditional polypropylene composite material, so the embodiments of the present application can illustrate that the prepared new glass fiber and polypropylene composite material has a lower density and lighter weight.

[0090] In the following, for the above structural design, a comprehensive analysis of the structure's modal, strength stress, etc. is performed to analyze whether its assembly structure meets the design requirements.

[0091] First, the structural modes are compared and analyzed to obtain the first-order modal vibration type and frequency results (see Table 2 for details). The first-order mode of the traditional glass fiber polypropylene reinforced composite material is 33.09Hz, and the first-order mode of the lightweight glass fiber polypropylene reinforced composite material prepared by the present application is 33.21Hz, which meets the design requirement of ≥30Hz. This shows that the strength of the structure designed by the present application, whether it is a traditional polypropylene composite material or a polypropylene composite material provided by the present application, can meet the design requirements of the first-order mode. The structure designed by the present application is optimized to meet the design requirements.

[0092] To simulate the strength of the auxiliary instrument panel under driving conditions, accelerations in three directions are applied to the auxiliary instrument panel system. For vertical impact conditions, the load is -2.5g; for turning conditions, the load is -1g, and the width direction x of the auxiliary instrument is +2g; for emergency braking conditions, the height direction Z of the auxiliary instrument is loaded with -1g, and the width direction x of the auxiliary instrument is loaded with -2g; the required strength is ≤80MPa. Through testing and analysis of vertical conditions, turning conditions, and emergency braking conditions, the maximum stress obtained in the vertical condition is 3.8MPa; the maximum stress obtained in the test turning condition is 2.3MPa; the maximum stress obtained in the test emergency braking condition is 5.8MPa; based on the above strength analysis results, it is found that: through the loading load analysis of the weakest part, the maximum stress value is 5.8MPa, which is much smaller than the design requirement of strength ≤80MPa. It can be concluded that the selection of structural materials and structural optimization are to meet the design requirements.

[0093] Product lightweighting can be achieved through optimization in material selection, structural design, and other aspects. The results show that the auxiliary instrument frame designed in this application, using the lightweight glass fiber reinforced polypropylene composite material provided by this application, can achieve weight reductions of 13.02%, 10.03%, and 9.36% respectively compared to traditional glass polypropylene composite materials, and the assembly achieves an average weight reduction of more than 11%. For example, the mass of a traditional auxiliary instrument assembly made of traditional polypropylene composite materials is 2.45kg, and the mass of an auxiliary instrument assembly made of the lightweight glass fiber reinforced polypropylene composite material of this application is 2.2kg. The lightweight effect is 11.36%.

[0094] The present application also provides a vehicle, which can be a gasoline car, a diesel car, an electric car, or other types of cars. For example, it can be an electric vehicle / electric vehicle (EV), a pure electric vehicle (PEV / BEV), a hybrid electric vehicle (HEV), a range extended electric vehicle (REEV), a plug-in hybrid electric vehicle (PHEV), a new energy vehicle (NEV), etc. Including the injection molded parts provided by the present application above, through the improvement of its materials, the optimization of its structure, and the optimization of its process manufacturing, it can meet the design and product manufacturing, achieve the design requirements of lightweight and strength, provide technical manufacturing for the strengthening of vehicles, and can be widely used in commercial vehicles on the current market.

[0095] It should be noted that the technical solutions or technical features described in the above embodiments can be combined or supplemented with each other without causing conflicts. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the drawings; all modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. An injection molded part for a vehicle auxiliary instrument assembly, characterized in that: The injection molded part is made of a polypropylene composite material, and the polypropylene composite material at least includes the following components counted by weight: 30-35 parts of high crystalline copolymer polypropylene; Homopolymer polypropylene 25-30 parts; Glass fiber 25-30 parts; 3-5 parts of toughening agent, 2-3 parts of nucleating agent, 0.2-0.4 parts of whiskers; The specification of the glass fiber is 2400tex.

2. The injection molded part for a vehicle auxiliary instrument assembly according to claim 1, characterized in that: The polypropylene composite material further comprises the following components counted by weight: Antioxidant 0.1-0.3 parts, lubricant 0.1-0.3 parts, scratch resistant agent 0.1-0.3 parts, light stabilizer 0.05-0.15 parts.

3. The injection molded part for a vehicle auxiliary instrument assembly according to claim 2, characterized in that: The toughening agent is selected from one or more of ethylene propylene diene monomer rubber (EPDM), ethylene propylene rubber (EPR), thermoplastic elastomer (SEBS), and polyolefin elastomer (POE).

4. The injection molded part for a vehicle auxiliary instrument assembly according to any one of claims 1 to 3, characterized in that: The side portion of the injection molded part comprises a first side wall and a second side wall which are arranged opposite to each other, the first side wall is used to fix parts inside the injection molded part, a first reinforcing rib which protrudes outward is provided on the surface of the first side wall, and the first reinforcing rib is distributed in a polygonal shape, and along the height direction of the injection molded part, the first side wall comprises a first area, a second area and a third area which are arranged in sequence up and down, and the number of parts fixed in the second area is greater than the number of parts fixed in the first area, and greater than the number of parts fixed in the third area; The first reinforcing ribs in the first area are distributed as a plurality of first polygons, the first reinforcing ribs in the second area are distributed as a plurality of second polygons, and the first reinforcing ribs in the third area are distributed as a plurality of third polygons, wherein the number of sides of the second polygons is greater than the number of sides of the first polygons and greater than the number of sides of the third polygons.

5. The injection molded part for a vehicle auxiliary instrument assembly according to claim 4, characterized in that: The surface of the second side wall is provided with second reinforcing ribs protruding outward, and the second reinforcing ribs are distributed in the form of a plurality of regular hexagons on the second side wall.

6. The injection molded part for a vehicle auxiliary instrument assembly according to claim 4, characterized in that: The side portion of the injection molded part also includes a third side wall, which connects the first side wall and the second side wall, is provided with a drawer opening, and is also provided with a third reinforcing rib, which extends toward the interior of the injection molded part, and has a double H-shaped cross-section.

7. The injection molded part for a vehicle auxiliary instrument assembly according to claim 6, characterized in that: The injection molded part further includes a top wall, three sides of which are respectively connected to the first side wall, the second side wall and the third side wall, and along the thickness direction of the injection molded part, the length of the top wall is less than the length of the first side wall; Along the thickness direction of the injection molded part, the first region includes a first sub-region and a second sub-region distributed side by side front and back, and the side length of the top wall includes the side length of the first sub-region and part of the side length of the second sub-region, the reinforcement ribs of the first sub-region are distributed in a plurality of squares, and the reinforcement ribs of the second sub-region are distributed in a plurality of rectangles.

8. The injection molded part for a vehicle auxiliary instrument assembly according to claim 7, characterized in that: The top wall is provided with at least one first protrusion facing the inside of the injection molded part, and at least one second protrusion facing the outside of the injection molded part; and / or The top wall is provided with a plurality of weight-reducing holes.

9. A method for preparing an injection molded part for a vehicle auxiliary instrument assembly, characterized in that: include: The raw materials are mixed to form a polypropylene composite material, wherein the raw materials include: 30-35 parts of high crystalline copolymer polypropylene, 25-30 parts of homopolymer polypropylene, 25-30 parts of glass fiber, 3-5 parts of toughening agent, 2-3 parts of nucleating agent, 0.2-0.4 parts of whisker, 0.1-0.3 parts of antioxidant, 0.1-0.3 parts of lubricant, 0.1-0.3 parts of scratch resistance agent, 0.05-0.15 parts of light stabilizer, wherein the specification of the glass fiber is 2400tex; The molten polypropylene composite material is integrally injection-molded into the injection molded part through an injection mold.

10. The method for preparing an injection molded part for a vehicle auxiliary instrument assembly according to claim 9, characterized in that: In the step of integrally injecting the molten polypropylene composite material into the injection molded part through an injection mold, the temperature of the injection mold is 50-60° C., the melt temperature is 230-240° C., the injection speed is 40-60 mm / s, the back pressure is 165-170 bar, and the holding pressure is 30-42 MPa.

11. A vehicle, characterized in that: The invention comprises the injection molded part according to any one of claims 1 to 8.

Images