Automobile trunk interior trim part and manufacturing method and application thereof

Abstract

The invention relates to an automobile trunk interior trim part and a manufacturing method and application thereof, the automobile trunk interior trim part comprises a raising carpet layer and a composite base material layer which are arranged from outside to inside, and the composite base material layer is of a layered structure formed by compounding a PP film and a PET forming felt. Compared with the prior art, a traditional PE film is replaced with the PP film, the integrated forming technology is replaced with the split forming technology, and on the premise that the advantages of light weight and low cost of a PET forming felt base material are reserved, the rigidity, heat resistance and surface attractiveness of parts can be synchronously improved.

Description

Technical Field

[0001] This invention relates to the field of automotive interior parts technology, and in particular to an automotive trunk interior part, its manufacturing method, and its application. Background Technology

[0002] The side panel of the trunk is a key interior component of the car trunk system. Its main functions are to cover the internal sheet metal structure to improve aesthetics, prevent stored items from scratching the rough sheet metal, and play a role in sound absorption and insulation, which helps to improve the vehicle's NVH performance.

[0003] Currently, SUV trunk side panels on the market generally adopt a split upper and lower assembly structure. The upper part is usually a PP (polypropylene) injection-molded plastic substrate, used to provide support for the main structure; the lower part is a soft felt assembly, whose typical structure includes, from the outside to the inside, a pile carpet surface layer 1, a PE (polyethylene) film adhesive layer 3, and a PET (polyethylene terephthalate) molded felt 22, such as... Figure 1 As shown, this felt assembly is mostly manufactured using an integrated hot-press molding process, where a pile carpet and PET molded felt are bonded together using a PE film under heat and pressure. The upper and lower parts are mechanically connected primarily through ultrasonic welding of BOSS columns or a snap-fit ​​structure.

[0004] However, the existing structure and process described above have several inherent defects that restrict further improvement in product performance: First, the structural rigidity and dimensional stability are insufficient. The core support layer of the felt assembly is a composite structure of "PE film + PET molded felt," which has relatively weak overall rigidity. During long-term storage or use, it is prone to warping, collapse, and other plastic deformations due to internal stress or external loads, affecting assembly reliability and appearance quality. Second, environmental reliability is poor. The heat resistance of PE and PET materials is limited. When the vehicle is in a high-temperature or sun-exposed environment in summer, the temperature inside the trunk may rise sharply, causing the felt assembly to soften, deform more severely, and even leading to problems such as interlayer delamination and blistering, making it difficult to guarantee product durability. Finally, the surface texture and aesthetics are compromised. During the high-temperature and high-pressure one-piece molding process, the pile surface of the pile carpet is easily over-compressed, resulting in a poor pile feel and hardened touch, affecting the high-end look and user experience of the interior.

[0005] Patent publication number CN116080162A discloses a side trim panel for an automotive trunk using a fiberglass composite structure. This design replaces the core layer of the felt assembly with a fiberglass board, forming a multi-layered composite structure of "pile carpet / first PP film / fiberglass board / second PP film / non-woven fabric". While the fiberglass board significantly improves the rigidity, sound insulation, and flame retardant properties of the parts, the fiberglass board and multi-layered composite structure lead to a significant increase in raw material and manufacturing costs; the parts are also heavier, which is detrimental to overall vehicle lightweighting; furthermore, the structure is relatively complex, requiring higher standards of production process control.

[0006] Therefore, when faced with the cost and performance requirements of different vehicle models, how to develop a new solution that can simultaneously improve the rigidity, heat resistance and surface aesthetics of parts while retaining the advantages of lightweight and low cost of PET molding felt substrate has become a practical and important technical problem in this field. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art and provide an automotive trunk interior part, its manufacturing method and application, which can simultaneously improve the rigidity, heat resistance and surface aesthetics of the parts while retaining the advantages of lightweight and low cost of PET molded felt substrate.

[0008] The objective of this invention can be achieved through the following technical solutions: One of the technical solutions of the present invention is to provide an interior trim component for a car trunk, comprising a pile carpet layer and a composite substrate layer arranged from the outside to the inside, wherein the composite substrate layer is a layered structure composed of PP film and PET molded felt.

[0009] Furthermore, the PP film in the composite substrate layer is adjacent to the pile carpet layer.

[0010] Furthermore, the thickness of the pile carpet layer is 2-3 mm, and the weight is 400-600 g / m². 2 ; The PP film has a thickness of 1~2mm and a basis weight of 110~150g / m³. 2 Its Shore hardness is 70-80, and its melting point is 164-170℃; The PET molding felt has a thickness of 3-4 mm and a basis weight of 1100-1500 g / m². 2 .

[0011] The second technical solution of the present invention provides a method for manufacturing interior trim parts for a car trunk, comprising the following steps: S1. Prefabricated composite substrate layer: PP film is combined with PET molding felt to form a composite substrate layer; S2. Laying and Separate Pressing: Lay the pile carpet layer in the mold cavity, and then cover the pile carpet layer with the composite substrate layer to form a composite material between the pile carpet layer and the composite substrate layer. S3. Post-processing: Remove the molded parts from the mold and trim them to obtain the finished luggage side panel.

[0012] Furthermore, in step S1, the PP film and PET molding felt are formed by thermal bonding.

[0013] Furthermore, the parameters for the thermal bonding are: heating temperature of 240~260℃ and heating time of 160~180s. If the heating temperature is too low or the heating time is insufficient, the material will not be fully cured, and the internal structure will not be sufficiently softened, thus affecting its tensile properties and reducing its ductility. The PET molding felt will then be prone to breakage during subsequent processing. Conversely, if the heating temperature is too high or the heating time is too long, the material is prone to overheating, leading to thermal degradation or even localized carbonization, resulting in embrittlement of the molding felt and a significant reduction in its mechanical properties.

[0014] Furthermore, the thermal bonding is performed in an oven, which is preheated to 240~260°C before heating.

[0015] Furthermore, in step S2, the pile carpet layer is laid in the mold cavity with the carpet surface facing down, and then the composite substrate layer is covered on the pile carpet layer with the PP film facing down.

[0016] Furthermore, in step S2, the pile carpet layer and the composite substrate layer are bonded together as one unit through a pressing process.

[0017] Furthermore, the parameters of the pressing process are: pre-pressure 2-3 MPa, pre-pressure time 10-20 s; holding pressure 13-16 MPa, holding pressure time 80-100 s. If the applied pressure is insufficient, the preset hole position cannot be completely cut off, and manual finishing is required. This process is not only inefficient but also easily causes scratches or damage to the material. On the other hand, if the pressure is too high, although the punching effect can be guaranteed, it will aggravate the wear of the die edge, affect its service life, and increase production costs.

[0018] Furthermore, the pile carpet layer is an independent, uncomposite single material layer before pressing; the PP film and PET molded felt in the composite substrate layer are pre-composite intermediates before pressing. The pile carpet layer and the composite substrate layer are formed by hot-melt bonding of the PP film during the pressing process.

[0019] The third technical solution of the present invention is to provide an application of an interior trim component for an automobile trunk, wherein the interior trim component is used to manufacture a side trim panel for an automobile trunk.

[0020] Compared with the prior art, the present invention has the following advantages: (1) Significantly improve the rigidity and dimensional stability of parts: Replacing the adhesive layer material from PE film to PP film is the core of this solution. The Shore hardness of PP material (approximately 70-80) is significantly higher than that of PE material (approximately 61-63). Shore hardness is an indicator of a material's resistance to elastic deformation; the higher the value, the "harder" the material and the stronger its resistance to deformation. Therefore, PP film, as an intermediate adhesive layer, provides a more robust "skeleton" for the entire composite substrate layer, greatly enhancing the overall structural rigidity and creep resistance of the parts, thus solving the problem of easy deformation after long-term storage. The reduced deformation also avoids collisions and abnormal noises caused by changes in gaps with surrounding parts.

[0021] (2) Significantly improved high-temperature resistance: The melting point of PP material (approximately 164~170℃) is much higher than that of PE material (approximately 85~136℃). This means that PP film-based composites can withstand higher ambient temperatures without softening, melting, or losing structural strength. In extreme environments where car trunks may reach 70~80℃ or even higher in summer, PE film-based parts are close to their softening point and are prone to deformation; while PP film-based parts are far from their heat distortion temperature and can still maintain the stability of their shape and function, thus ensuring the durability and reliability of the product.

[0022] (3) Optimizing Surface Texture and Appearance Consistency: In the one-piece molding process, the pile carpet surface layer needs to be heated and pressed for a long time in a high-temperature and high-pressure mold along with the PE film and PET felt. This process will irreversibly damage the carpet pile, making the pile feel worse (similar to being ironed flat), and the high temperature may make the fiber color brighter, resulting in color difference. The key point of the split molding process of the present invention is that the pile carpet itself is not heated in an oven, but is laid directly on the mold as a "cold material". Only the pre-made PP film / PET felt composite needs to be heated. Under pressure, the PP film melt layer of the composite after heating is sufficient to bond well with the back of the pile carpet, while avoiding the front of the pile carpet (carpet surface) being directly exposed to high temperature for a long time. This preserves the original three-dimensionality and soft touch of the pile to the greatest extent, and the color does not change, ensuring consistency and coordination in color and texture with other soft trim parts in the car that have not been treated with the same high temperature, significantly improving the sense of luxury of the interior.

[0023] (4) The main materials of this invention are PP film and PET molding felt, both of which are common and relatively low-cost chemical products, and the raw material costs are controllable. Under the premise of meeting performance requirements, the manufacturing cost is significantly reduced, making it more suitable for cost-sensitive mass-produced models and giving it a stronger price competitiveness. Moreover, the density of PET molding felt is relatively low, which helps to achieve the lightweighting of parts. In addition, the composite substrate layer is only a pre-composite of PP film and PET felt, with a relatively simple structure, a wider process window during heating and molding, and easier control. The production cycle may be faster, the production efficiency is higher, the yield rate is easier to guarantee, and the production risk and management cost are reduced. Attached Figure Description

[0024] Figure 1 A structural diagram of traditional automotive trunk interior components; Figure 2 This is a structural schematic diagram of the interior trim of the car trunk shown in Example 1.

[0025] 1-Pile carpet layer; 2-Composite substrate layer, 21-PP film, 22-PET molding felt; 3-PE film adhesive layer. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments. In the following embodiments or examples, unless otherwise specified, the functional components or structures are conventional components or structures used in the art to achieve the corresponding functions.

[0027] It should be noted that in the description of this invention, the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] Example 1 A type of car trunk interior trim, such as Figure 2 As shown, the material includes a pile carpet layer 1 and a composite substrate layer 2 arranged from the outside in. The composite substrate layer 2 is a layered structure composed of a PP film 21 and a PET molded felt 22. The PP film 21 in the composite substrate layer 2 is adjacent to the pile carpet layer 1.

[0030] In this embodiment, the pile carpet layer 1 has a thickness of 2.5 mm and a weight of 450 g / m². 2 ; The PP film 21 has a thickness of 1.5 mm and a basis weight of 120 g / m³. 2 It has a Shore hardness of 75 and a melting point of 165℃. The PET molding felt 22 has a thickness of 3.5 mm and a basis weight of 1200 g / m². 2 .

[0031] A method for manufacturing an interior trim part for a car trunk includes the following steps: S1. Pre-fabricated composite substrate layer 1: PP film 21 is laminated with PET molding felt 22 to form a PP film / PET molding felt composite. The PP film / PET molding felt composite is placed in an oven preheated to 250°C and heated for 170 seconds to form composite substrate layer 1.

[0032] S2. Laying and Separate Pressing: The pile carpet layer 1 is laid in the mold cavity with the carpet surface facing down. Then, the composite substrate layer 1 is covered on the pile carpet layer 1 with the PP film 21 facing down. Subsequently, the mold is pre-pressed at 2.5 MPa for 15 seconds, and then held at 15 MPa for 90 seconds to form the composite layers. Before pressing, the pile carpet layer 1 is an independent, uncomposite single material layer; the PP film 21 and PET molding felt 22 in the composite substrate layer 2 are pre-composite intermediates before pressing; the pile carpet layer 2 and the composite substrate layer 3 are formed by thermally melting and bonding the PP film 21 during the pressing process.

[0033] S3. Post-processing: The molded part is removed from the mold and trimmed to obtain the finished trunk interior trim. This trim is then used as a felt part to manufacture the side panel of the car trunk.

[0034] This embodiment replaces the traditional PE film for interior trim parts with PP film, significantly enhancing the hardness of the trim parts. This makes them less prone to deformation after prolonged storage and reduces the likelihood of rattling noises from other parts. Furthermore, its high-temperature resistance is significantly improved, withstanding temperatures above 120℃. Even in extreme high-temperature environments, the performance of the trunk side trim panel remains unaffected, and it is less prone to deformation after prolonged storage. In addition, by replacing the one-piece molding process with a split molding process, the pile texture of the trunk side trim panel's carpet is significantly improved, and the color matching between the side trim panel and other soft trim parts is significantly enhanced. When pile carpets are heated in an oven, the surface pile flattens, and the color becomes too bright, which is detrimental to color matching with other soft trim parts. In the split molding process, the pile carpet does not require oven heating, resulting in a better surface pile texture and no color change.

[0035] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. An automotive trunk interior trim piece, characterized by, The application relates to a luggage case side panel, which comprises a pile carpet layer (1) and a composite base material layer (2) arranged from the outside to the inside, wherein the composite base material layer (2) is a layered structure composed of a PP film (21) and a PET formed felt (22).

2. The interior trim piece for a trunk of a vehicle of claim 1, wherein, The PP film (21) in the composite base material layer (2) is adjacent to the pile carpet layer (1).

3. The interior trim piece of claim 1, wherein, The pile carpet layer (1) has a thickness of 2-3 mm and a weight of 400-600 g / m 2 ; The PP film (21) has a thickness of 1-2 mm, a weight of 110-150 g / m 2 , a Shore hardness of 70-80, and a melting point of 164-170℃. The PET forming mat (22) has a thickness of 3-4 mm and a grammage of 1100-1500 g / m 2 .

4. The method of any one of claims 1 to 3, wherein the method further comprises the step of: The application further discloses a manufacturing method of the luggage case side panel. ​ S1, pre-preparing a composite base material layer (1): the PP film (21) is combined with the PET formed felt (22) to form the composite base material layer (1); S2, laying and separating and pressing: the pile carpet layer (1) is laid in a mold cavity, and then the composite base material layer (1) is covered on the pile carpet layer (1) to combine the pile carpet layer (1) and the composite base material layer (2) into a shape; S3, post-processing: the shaped part is taken out from the mold, and edge trimming is performed to obtain a finished luggage case side panel.

5. The method of claim 4, wherein the step of applying the adhesive is performed by a hot-melt adhesive gun. In step S1, the PP film (21) and the PET formed felt (22) are combined through heat.

6. The method of claim 5, wherein the step of applying the adhesive is performed by a hot-melt adhesive gun. The heat-combining parameters are as follows: the heating temperature is 240-260 DEG C, and the heating time is 160-180 s.

7. The method of claim 4, wherein the step of applying the adhesive is performed by a hot-melt adhesive gun. In step S2, the pile carpet layer (1) is laid in the mold cavity with the carpet surface facing downward, and then the composite base material layer (1) is covered on the pile carpet layer (1) with the PP film (21) facing downward.

8. The method of claim 4, wherein the step of applying the adhesive is performed by a hot-melt adhesive gun. In step S2, the pile carpet layer (1) and the composite base material layer (2) are integrated through a pressing process.

9. The method of claim 8, wherein the step of applying the adhesive is performed by a hot-melt adhesive gun. The pressing process parameters are as follows: the pre-pressing pressure is 2-3 Mpa, the pre-pressing time is 10-20 s, the pressure maintaining pressure is 13-16 Mpa, and the pressure maintaining time is 80-100 s.

10. The application of the luggage case side panel according to any one of claims 1-3, wherein the inner decoration part is used for manufacturing a luggage case side panel.

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