Preparation method of automobile door panel

Abstract

The invention provides a preparation method of an automobile door panel. The preparation method specifically comprises the following steps: baking a raw material plate or a felt material; a structure is formed on the back face of the baked raw material plate or felt material in an injection molding mode through a mold pressing-injection molding-punching forming method, and therefore a semi-finished product framework is obtained; the semi-finished product framework is subjected to hole site punching treatment and then is subjected to polishing treatment and punching treatment in sequence, and a finished product framework is obtained; and compounding the finished skeleton with a skin or a fabric through an adsorption method or a hot pressing method, and further assembling to obtain the automobile door panel. Compared with the prior art, the raw material plate or the felt material is baked firstly, so that the material is more uniform, waste in the subsequent processing process is reduced, the utilization rate of the material is increased, and the structure is formed on the back surface of the raw material plate or the felt material in an injection molding manner by adopting a mold pressing-injection molding-punching forming method; the finished skeleton is compounded with the skin or the fabric through an adsorption method or a hot pressing method, so that tight combination between the skin or the fabric and the skeleton can be ensured, and the quality problems of bubbles, wrinkles and the like are avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of automotive sheet materials, and particularly relates to a preparation method for automotive door panels. Background Art

[0002] With the rapid development of the automotive industry and the continuous improvement of vehicle performance and comfort by consumers, the design and manufacturing technologies of automotive components are also constantly advancing. As an important part of the automotive interior, automotive door panels not only perform functions such as protecting the safety of passengers in the vehicle and reducing noise, but also have an important impact on the aesthetics and comfort of the vehicle. Therefore, the design and manufacturing quality directly relate to the overall quality of the vehicle.

[0003] Traditional manufacturing processes for automotive door panels mainly include multiple steps such as material selection, mold design and production, injection molding, and surface treatment. However, the existing production processes have the following problems:

[0004] 1. Complex processes: From raw material preparation to the completion of the final product, the entire production process involves multiple processes, including but not limited to pretreatment, injection molding, cooling, demolding, trimming, etc., which results in low production efficiency.

[0005] 2. High cost: Due to the cumbersome processes and the need to use precision production equipment, the production cost is relatively high. In addition, the complex processes also increase the defective rate, further raising the cost.

[0006] 3. Long production cycle: The serial operation of multiple steps prolongs the production cycle of a single product, making it difficult to meet the rapidly changing market demands, especially in small batch or customized production modes.

[0007] 4. High environmental protection pressure: Traditional manufacturing processes may produce harmful substance emissions, which have a certain impact on the environment and do not conform to the current social advocacy for green production.

[0008] 5. Limited product performance: Existing automotive door panels still need to be improved in terms of mechanical strength, heat resistance, chemical resistance, etc., especially in terms of high strength, lightweight, and environmental protection performance.

[0009] In view of the above problems, there is an urgent need in the market for a new method that can simplify the process flow, reduce costs, shorten the production cycle, improve product performance, and at the same time meet environmental protection requirements to improve the production of automotive door panels. Summary of the Invention

[0010] In order to solve the above existing technical problems, the present invention provides a preparation method for automotive door panels, which realizes the efficient and high-quality preparation of automotive door panels by optimizing the process parameters of each step.

[0011] The preparation method of the automotive door panel provided by the present invention specifically includes the following steps: S1. Bake the raw material board or felt material; S2. Inject a structure on the back of the baked raw material board or felt material by means of molding - injection - punching to obtain a semi - finished skeleton; S3. After subjecting the semi - finished skeleton to hole punching treatment, perform grinding treatment and drilling treatment in sequence to obtain a finished skeleton; S4. After the finished skeleton is compounded with the skin or fabric by adsorption or hot - pressing method, further assembly is carried out to obtain the automotive door panel.

[0012] Compared with the prior art, by baking the raw material board or felt material first, the present invention can make the material more uniform, reduce waste in the subsequent processing process, and improve the material utilization rate. By using the method of molding - injection - punching to inject a structure on the back of the raw material board or felt material, this design can effectively increase the overall structural strength of the door panel and also ensure the lightweight requirement of the door panel; the finished skeleton is compounded with the skin or fabric by adsorption or hot - pressing method, and such a process can ensure the tight combination between the skin or fabric and the skeleton, avoiding quality problems such as bubbles and wrinkles, thereby improving the appearance beauty and touch of the product.

[0013] In some embodiments, fibers are doped in the raw material board or felt material, and the fibers are selected from at least one of PP fiber, PET fiber, PA fiber, glass fiber, hemp fiber, and bamboo fiber.

[0014] Compared with the prior art, by adding fibers, the present invention has the following advantages: The addition of fibers significantly improves the mechanical strength, stiffness, and toughness of the door panel, making it not easily deformed or damaged when impacted, and improving the safety performance; compared with traditional metal materials, these fiber materials are usually lighter, which helps to reduce the overall weight of the vehicle, thereby improving fuel economy and reducing carbon emissions. Especially glass fiber and PA fiber, they have good thermal stability and dimensional stability, and can maintain their shape unchanged even in high - temperature environments, and are suitable for the automotive interior environment; while PP fiber and PET fiber have good corrosion resistance and can resist the erosion of various chemicals, extending the service life of the door panel; natural fiber materials such as hemp fiber and bamboo fiber are renewable resources, and produce less waste during the production process and are easy to recycle, meeting the requirements of sustainable development. By selecting appropriate fiber materials, the production cost can be controlled while ensuring performance, achieving the optimal cost - effectiveness.

[0015] In some embodiments, in step S1, the baking temperature is 180 - 280 °C, and the baking time is 40 - 140 s.

[0016] Compared with the prior art, the advantages of the present invention using the above parameters are as follows: in the temperature range of 180 - 280 °C, it can ensure that the fibers and matrix materials in the raw material board or felt are uniformly heated, avoiding problems such as local overheating or insufficient heating. Uniform heating helps the fibers to disperse and fix better, improving the overall performance of the material. The baking time of 40 - 140 seconds is relatively short, which can significantly improve the efficiency of the production line, reduce energy consumption, and lower production costs. The short baking time also helps to reduce the degradation risk of the material at high temperatures and maintain the original performance of the material.

[0017] In some embodiments, in the step S2, the parameters of the molding and injection molding processes are as follows: the clamping force is 180 - 210T, the injection time is 2 - 15s, and the injection temperature is 200 - 250 °C.

[0018] Compared with the prior art, the advantages of the present invention using the above parameters are as follows: a higher clamping force can ensure that the mold is tightly closed during the injection molding process, preventing material overflow, and at the same time ensuring the uniform distribution of the material in the mold cavity, which helps to improve the density and surface quality of the product; a shorter injection time can quickly inject the molten material into the mold cavity, reducing the degradation of the material at high temperatures, and at the same time ensuring that the material quickly fills the mold cavity, avoiding the formation of bubbles and voids; in the temperature range of 200 - 250 °C, the material can reach the best fluidity and plasticity, which helps to improve the filling effect and molding quality of the material. At the same time, an appropriate temperature can reduce the internal stress of the material and improve the mechanical properties of the product.

[0019] In addition, the present invention uses a vertical injection molding machine, which has the following advantages: small floor area: due to its vertical layout, the vertical injection molding machine can save floor space in the workshop and is suitable for production environments with limited space; convenient operation: for some products that require manual operation or auxiliary assembly, the vertical injection molding machine has its operation surface close to the ground, making the operation more convenient; suitable for multi-cavity molds: the vertical machine can better handle multi-cavity molds, which is beneficial to improving production efficiency In some embodiments, in the step S3, the pressure of the punching process is 1600 - 1800 KN.

[0020] Compared with the prior art, the advantages of the present invention using the above parameters are as follows: high pressure can ensure that the punching tool can quickly and accurately penetrate the material when contacting the material, reducing burrs and irregularities at the edges and improving cutting accuracy. High pressure can reduce the deformation of the material during the punching process and ensure that the size and shape of the cut parts meet the design requirements.

[0021] In some embodiments, in the step S4, the material of the skin is selected from one of TPO, PU, PVC, ultra-fine fiber, and genuine leather; the material of the fabric is selected from one of suede-like fabric, knitted fabric, flocked blanket surface, tufted blanket surface, and printed non-woven fabric.

[0022] Compared with the prior art, the advantages of the present invention in using the above materials are as follows: The selection of a variety of materials can meet the needs and preferences of different customers, providing diverse interior styles. Different materials have different touches and appearances, which can enhance the comfort and high-class sense of the interior. All kinds of materials have good abrasion resistance, tear resistance and weather resistance, ensuring the long-term use performance of the interior. Some materials (such as TPO, ultra-fine fiber) have the characteristics of environmental protection and recyclability, meeting the requirements of sustainable development in modern manufacturing.

[0023] In some embodiments, in the step S4, the adsorption method is selected from female mold adsorption, male mold adsorption or vacuum activation.

[0024] Compared with the prior art, the present invention can select the above three adsorption methods, and the specific selection basis is as follows: The female mold adsorption process uses a female mold with a leather grain pattern, which can ensure clear and uniform leather grains without stretching deformation, and is particularly suitable for occasions requiring high-quality leather grain effects; The male mold adsorption mold is usually processed from aluminum alloy, with low manufacturing cost, long mold life and high production efficiency; The vacuum activation process can achieve high-precision adsorption and fixation, ensuring uniform distribution and tight fitting of materials.

[0025] In some embodiments, the parameters of the female mold adsorption are as follows: heating temperature 120 - 200 °C, adsorption time 10 - 60 s, adsorption pressure -60 kPa to -80 kPa.

[0026] The advantages of the present invention in using the above parameters are as follows: Within this temperature range, the material can reach the best softening state, which is beneficial to the uniform distribution and forming of the material on the female mold. This helps to ensure the clarity and uniformity of the leather grains, reducing the occurrence of blurred or incomplete leather grains; And the appropriate adsorption time can ensure the full fitting of the material on the female mold, while avoiding over-stretching or deformation of the material caused by too long adsorption time, maintaining the integrity of the leather grains.

[0027] In some embodiments, the parameters of the male mold adsorption are as follows: heating temperature 120 - 170 °C, adsorption time 15 - 40 s, adsorption pressure -60 kPa - -80 kPa.

[0028] The advantages of the present invention in using the above parameters are as follows: Within this temperature range, the material can reach the best softening state, which is beneficial to the uniform distribution and forming of the material on the male mold. This helps to ensure the tight fitting of the material on the male mold, reducing the generation of bubbles and voids; The appropriate adsorption time can ensure the full fitting of the material on the male mold, while avoiding over-stretching or deformation of the material caused by too long adsorption time, maintaining the integrity and performance of the material.

[0029] In some embodiments, the parameters of the vacuum activation are as follows: the heating temperature is 45 - 75°C, the pressure holding time is 15 - 50 s, and the vacuum degree is -60 kPa to -80 kPa.

[0030] The advantages of the present invention using the above parameters are as follows: within this temperature range, the material can reach an appropriate softening state, which is beneficial to the uniform distribution and molding of the material on the mold. The lower heating temperature can reduce the thermal degradation of the material and maintain the physical properties of the material; the moderate pressure holding time can ensure the full adhesion of the material to the mold, while avoiding excessive stretching or deformation of the material caused by too long pressure holding time, and maintaining the integrity and performance of the material; the moderate vacuum degree can ensure the rapid and uniform adsorption of the material on the mold, reduce the generation of bubbles and voids, and improve the density of the material.

[0031] In some embodiments, in step S4, the parameters of the hot pressing method are as follows: the heating temperature is 45 - 75°C, and the pressure holding time is 15 - 90 s.

[0032] The advantages of the present invention using the above parameters are as follows: within this temperature range, the material can reach an appropriate softening state, which is beneficial to the uniform distribution and molding of the material on the mold. The lower heating temperature can reduce the thermal degradation of the material and maintain the physical properties of the material; the moderate pressure holding time can ensure the full adhesion of the material to the mold, while avoiding excessive stretching or deformation of the material caused by too long pressure holding time, and maintaining the integrity and performance of the material.

[0033] In some embodiments, in step S4, the adhesive used for adsorption is glue, and the material of the glue is selected from one of reactive polyurethane hot melt adhesive, reactive polyolefin hot melt adhesive, non-reactive polyolefin hot melt adhesive, and waterborne polyurethane adhesive.

[0034] Compared with the prior art, the advantages of the present invention using the above glue are as follows: the reactive polyurethane hot melt adhesive has a very high bonding strength, can provide a long-term stable bonding effect, has excellent chemical resistance, and can resist the erosion of various chemical substances, and is suitable for various environments; the reactive polyolefin hot melt adhesive has good initial tackiness, can provide sufficient adhesion in a short time, has excellent heat resistance, and can maintain stable performance at high temperatures; the non-reactive polyolefin hot melt adhesive has a fast curing speed, can significantly improve production efficiency and reduce waiting time; while the waterborne polyurethane adhesive is solvent-free, has good environmental protection performance, and meets the sustainable development requirements of modern manufacturing. Detailed Embodiments

[0035] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following provides a detailed description of specific embodiments of the present invention. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not used to limit the parameter range described in the present invention. Reasonable variations derived therefrom are still within the protection scope of the claims of the present invention.

[0036] It should be noted that the endpoints and any values within the ranges disclosed herein are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0037] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. In some cases, for the purpose of clarification or facilitation of citation, terms with conventional meanings are defined herein. Such definitions herein should not be construed as indicating a significant difference from the conventional understanding in the art. The technical methods described or cited herein are generally well understood by those skilled in the art and are adopted by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments follows the protocols and parameters provided by the manufacturers.

[0038] The following describes the technical effects of the present invention in conjunction with specific embodiments.

[0039] Example 1: This example provides an automotive door panel, which is prepared by the following method: S1. Bake the raw material plate. The raw material plate is doped with fibers, and the fibers are PP fibers and PET fibers. The baking temperature is 180°C, and the baking time is 140 s. S2. Inject a structure on the back of the baked raw material plate through a molding - injection - punching forming method to obtain a semi - finished skeleton. The parameters for molding and injection are as follows: the clamping force is 180 T, the injection time is 2 s, and the injection temperature is 250°C. S3. After subjecting the semi - finished skeleton to hole punching treatment, perform grinding treatment and drilling treatment in sequence to obtain a finished skeleton. The pressure for punching treatment is 1600 KN. S4. After the finished skeleton and the skin are combined by adsorption, the automotive door panel is obtained through further assembly. The material of the skin is TPO; the adsorption method is female mold adsorption, and the parameters of the female mold adsorption are as follows: heating temperature 70°C, adsorption time 10 s, adsorption pressure -60 kPa. The adhesive used for adsorption is glue, and the material of the glue is reactive polyurethane hot melt adhesive.

[0040] Example 2 This example provides an automotive door panel, which is obtained through the following preparation method: S1. Bake the felt material. The felt material is doped with fibers, and the fibers are bamboo and wood fibers. The baking temperature is 160°C, and the baking time is 110 s. S2. Inject a structure on the back of the baked felt material through a molding - injection - punching method to obtain a semi - finished skeleton. The parameters of the molding and injection processes are as follows: clamping force 190 T, injection time 6 s, injection temperature 240°C. S3. After the semi - finished skeleton undergoes hole punching treatment, it is successively subjected to grinding treatment and hole drilling treatment to obtain a finished skeleton. The pressure of the punching treatment is 1650 KN. S4. After the finished skeleton and the fabric are combined by hot pressing, the automotive door panel is obtained through further assembly. The parameters of the hot pressing method are as follows: heating temperature 120°C, holding pressure time 15 s; the adhesive used for adsorption is glue, and the material of the glue is non - reactive polyolefin hot melt adhesive.

[0041] Example 3 This example provides an automotive door panel, which is obtained through the following preparation method: S1. Bake the raw material board. The raw material board is doped with fibers, and the fibers are glass fibers. The baking temperature is 210°C, and the baking time is 95 s. S2. Inject a structure on the back of the baked raw material board through a molding - injection - punching method to obtain a semi - finished skeleton. The parameters of the molding and injection processes are as follows: clamping force 195 T, injection time 8 s, injection temperature 225°C. S3. After the semi - finished skeleton undergoes hole punching treatment, it is successively subjected to grinding treatment and hole drilling treatment to obtain a finished skeleton. The pressure of the punching treatment is 1700 KN. S4. After the finished skeleton and the skin are combined by adsorption or hot pressing, the automotive door panel is obtained through further assembly. The material of the skin is genuine leather; the adsorption method is vacuum activation, and the parameters of the vacuum activation are as follows: heating temperature 60°C, holding pressure time 35 s, vacuum degree -70 kPa; the adhesive used for adsorption is glue, and the material of the glue is water - based polyurethane glue.

[0042] Example 4 This embodiment provides an automotive door panel, which is obtained through the following preparation method: S1. Bake the felt material. The felt material is doped with fibers, and the fibers are hemp fibers. The baking temperature is 180°C, and the baking time is 120 s. S2. Inject a structure on the back of the baked felt material by means of compression molding - injection molding - punching to obtain a semi-finished skeleton. The parameters for compression molding and injection molding are as follows: the clamping force is 200 T, the injection time is 12 s, and the injection temperature is 220°C. S3. After subjecting the semi-finished skeleton to hole punching treatment, perform grinding treatment and drilling treatment in sequence to obtain a finished skeleton. The pressure for punching treatment is 1750 KN. S4. After the finished skeleton is compounded with the fabric by means of vacuum activation, the automotive door panel is obtained through further assembly. The material of the fabric is suede-like; the parameters for vacuum activation are as follows: the heating temperature is 130°C, the pressure holding time is 25 s, and the vacuum degree is -75 kPa; the adhesive used for adsorption is glue, and the material of the glue is reactive polyolefin hot melt adhesive.

[0043] Example 5 This embodiment provides an automotive door panel, which is obtained through the following preparation method: S1. Bake the raw material board. The raw material board is doped with fibers, and the fibers are PP fibers and bamboo and wood fibers. The baking temperature is 165°C, and the baking time is 140 s. S2. Inject a structure on the back of the baked raw material board by means of compression molding - injection molding - punching to obtain a semi-finished skeleton. The parameters for compression molding and injection molding are as follows: the clamping force is 210 T, the injection time is 15 s, and the injection temperature is 215°C. S3. After subjecting the semi-finished skeleton to hole punching treatment, perform grinding treatment and drilling treatment in sequence to obtain a finished skeleton. The pressure for punching treatment is 1800 KN. S4. After the finished skeleton is compounded with the skin by means of adsorption, the automotive door panel is obtained through further assembly. The material of the skin is PU, and the adsorption method is male mold adsorption. The parameters for male mold adsorption are as follows: the heating temperature is 125°C, the adsorption time is 30 s, the adsorption pressure is -80 kPa, the adhesive used for adsorption is glue, and the material of the glue is non-reactive polyolefin hot melt adhesive.

[0044] Perform performance tests on the door panels obtained in Examples 1 - 3, as shown in Tables 1 and 2 specifically:

[0045]

[0046]

[0047] Although the present disclosure is disclosed as above, the scope of protection of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will all fall within the scope of protection of the present invention.

Claims

1. A preparation method of an automobile door panel, characterized in that, The preparation method specifically includes the following steps: S1. Bake the raw material board or felt material; S2. Inject a structure on the back of the baked raw material board or felt material by means of die pressing - injection molding - punching to obtain a semi-finished product skeleton; S3. After subjecting the semi-finished product skeleton to punching treatment of holes, perform grinding treatment and drilling treatment in sequence to obtain a finished product skeleton; S4. After the finished product skeleton is compounded with the skin or fabric by adsorption method or hot pressing method, further assembly is carried out to obtain an automobile door panel.

2. The preparation method according to claim 1, wherein Fibers are doped in the raw material board or felt material, and the fibers are selected from at least one of PP fiber, PET fiber, PA fiber, glass fiber, hemp fiber, and bamboo fiber.

3. The preparation method according to claim 1, characterized in that, In the step S1, the baking temperature is 180 - 280 °C, and the baking time is 40 - 140 s.

4. The preparation method according to claim 1, characterized in that, In the step S2, the parameters of die pressing and injection molding are as follows: the clamping force is 180 - 210 T, the injection time is 2 - 15 s, and the injection temperature is 200 - 250 °C.

5. The preparation method according to claim 1, characterized in that, In the step S3, the pressure of punching treatment is 1600 - 1800 KN.

6. The preparation method according to claim 1, characterized in that, In the step S4, the material of the skin is selected from one of TPO, PU, PVC, ultra-fine fiber, and genuine leather; the material of the fabric is selected from one of suede-like, knitted fabric, fleece blanket surface, tufted blanket surface, and printed non-woven fabric.

7. The preparation method according to claim 1, characterized in that, In the step S4, the adsorption method is selected from female mold adsorption, male mold adsorption, or vacuum activation.

8. The preparation method according to claim 7, characterized in that, The parameters of the female mold adsorption are as follows: the heating temperature is 120 - 200 °C, the adsorption time is 10 - 60 s, and the adsorption pressure is -60 kPa to -80 kPa; The parameters of the male mold adsorption are as follows: the heating temperature is 120 - 170 °C, the adsorption time is 15 - 40 s, and the adsorption pressure is -60 kPa - -80 kPa; The parameters of the vacuum activation are as follows: the heating temperature is 45 - 75 °C, the pressure holding time is 15 - 50 s, and the vacuum degree is -60 kPa to -80 kPa.

9. The preparation method according to claim 1, characterized in that, In the step S4, the parameters of the hot pressing method are as follows: the heating temperature is 45 - 75 °C, and the pressure holding time is 15 - 90 s.

10. The preparation method according to claim 1, characterized in that, In the step S4, the binder used for adsorption is glue, and the material of the glue is selected from one of reactive polyurethane hot melt adhesive, reactive polyolefin hot melt adhesive, non-reactive polyolefin hot melt adhesive, and waterborne polyurethane adhesive.

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