Preparation method of high-temperature-resistant decorative film for automobile exterior trim and coating-free treatment process thereof

Abstract

This invention discloses a method for preparing a high-temperature resistant decorative film for automotive exteriors and its paint-free treatment process, relating to the field of automotive decorative parts technology. The invention uses a high-melting-point polymer film as a substrate, coating one or more polymer layers onto the surface of the polymer film. The film prepared using this invention can be laminated with various metal substrates (such as stainless steel, aluminum, galvanized steel, etc.) and then processed through stamping, rolling, injection molding, etc., to meet the performance and appearance requirements of automotive interior and exterior parts and panels, eliminating the need for painting and other chemical surface treatment processes. This invention also provides a paint-free treatment process for automotive exterior parts. This process uses a method for preparing a high-temperature resistant decorative film specifically for automotive exteriors, and then laminates it with the metal substrates of automotive interior and exterior parts through online bonding or lamination.

Description

Technical Field

[0001] This invention relates to the field of automotive decorative accessories technology, specifically to a method for preparing a high-temperature resistant decorative film for automotive exteriors and its paint-free treatment process. Background Technology

[0002] With the continuous increase in people's travel needs, the global automotive industry is booming. Besides mainstream trends such as low-carbon environmental protection and artificial intelligence, the automotive exterior decoration field is also undergoing rapid transformation to cater to the trend of high-end appearance and meet consumers' increasingly demanding aesthetic needs. Currently, the surface preparation processes for automotive exterior components mainly rely on painting, pre-coating, and chemical treatments (electroplating, anodizing), and most of these are high-energy-consuming and high-polluting (high VOC emissions) manufacturing methods. Furthermore, they cannot adapt to various complex molding and preparation requirements, greatly limiting the production methods of automotive parts manufacturers and the assembly and integration methods of OEMs.

[0003] Compared to surface treatments such as painting, pre-coating, and chemical treatment, surface coating is a more economical, environmentally friendly, and flexible process. However, existing decorative films used in home appliances and construction are mostly cast films or blown films made by melting pigments and plastic particles with color masterbatches. These materials cannot meet the performance standards, appearance texture, and saturation requirements of the automotive exterior industry. In addition, car wraps (commonly known as car covers) commonly used in the automotive industry are mostly used for personalized exterior modifications in the automotive aftermarket. These films are mainly composed of modified polyurethane and polyvinyl chloride. Although they have short-term outdoor weather resistance and a bright and saturated appearance, they are too soft and easily scratched, making them unsuitable for various complex outdoor working conditions. While existing decorative films in the automotive exterior industry have high surface quality, strong adhesion to metal substrates, are not easily worn or peeled off, and have excellent weather resistance, they cannot adapt to manufacturing processes in high-temperature environments, such as integrated high-temperature lamination and high-temperature injection molding. Patent document CN105339404 discloses a paint substitute film for automobiles including a polymer layer. This decorative film has chemical resistance, weather resistance and tensile strength similar to paint, but its high temperature resistance is generally poor and cannot meet the process requirements of integrated high temperature lamination and high temperature injection molding. Summary of the Invention

[0004] To achieve the above objectives, the present invention specifically adopts the following technical solution: A method for preparing a high-temperature resistant decorative film for automotive exteriors and its paint-free treatment process, comprising a substrate layer, an interface layer, and a surface layer from the inside out, and further including the following preparation steps: S1: The substrate layer uses a high-melting-point polymer film as the substrate; S2: An interface layer is coated on the outside of the substrate layer; S3: Apply a surface layer to the outside of the interface layer.

[0005] Furthermore, the substrate layer is any one of polyamide compounds, fluoropolymers, polyetheretherketones, polyimides, polyethylene terephthalate, and polyphenylene sulfide.

[0006] Furthermore, the substrate layer has a melting point ≥150℃.

[0007] Furthermore, the coating thickness of the substrate layer is 10µm to 200µm.

[0008] Furthermore, the interface layer is composed of epoxy polymers, polyurethane polymers, and silicone polymers.

[0009] Furthermore, the surface layer is composed of one or more of aliphatic polyurethane polymers, acrylic polymers, silicone-modified polyester polymers, and fluoropolymers.

[0010] A paint-free treatment process for automotive exterior parts involves using a high-temperature resistant decorative film for automotive exterior parts prepared by the method described in any one of claims 1 to 9, and then applying or laminating the film to the metal substrate of the automotive interior and exterior parts via online lamination or lamination.

[0011] The beneficial effects of this invention are as follows: 1. This invention can be combined with various metal substrates (such as stainless steel, aluminum, galvanized steel, etc.) and then processed through stamping, rolling, injection molding and other processes to meet the performance and appearance requirements of automotive interior and exterior parts and panels, eliminating the need for painting and other chemical surface treatment processes.

[0012] 2. The high-temperature resistant decorative film obtained by the present invention has a beautiful surface appearance, rich texture and saturation, and excellent performance. It has excellent high-temperature resistance, weather resistance, and formability, and has strong adhesion to metal substrates, making it less prone to wear and peeling.

[0013] 3. This invention can significantly improve the quality of automotive parts manufacturers and OEMs, achieve lightweighting, increase efficiency, reduce costs, and alleviate environmental pressure. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the high-temperature resistant decorative film of the present invention; Reference numerals: 1. Substrate layer; 2. Interface layer; 3. Surface layer. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] like Figure 1 As shown in the figure, this embodiment provides a method for preparing a high-temperature resistant decorative film for automotive exteriors. The method uses a high-melting-point polymer film as a substrate and coats two layers of polymer coating on the surface of the polymer film to form a high-performance, colorful, high-temperature resistant, and high-weather-resistant automotive-grade decorative film. This decorative film can be applied to metal online or laminated with various metals for continuous molding of automotive interior and exterior parts, eliminating the need for repainting and turnover of automotive interior and exterior parts.

[0018] In this embodiment, high weather resistance refers to a product whose decorative film passes the exposure test for ≥1200 hours under the cyclic conditions of GB / T16422.2-2014; automotive-grade performance means that the decorative film must meet the enterprise standards set by a certain automobile OEM, such as scratch resistance, adhesion, water resistance, chemical resistance, acid and alkali resistance, high and low temperature cycling resistance, surface pencil hardness, and light aging resistance. Example 1

[0019] In this embodiment, the specific steps of the preparation method of the high-temperature resistant decorative film for automotive exterior trim are as follows: Step S1: Select a polyimide film with a thickness of 10um~200um as the substrate, preferably with a substrate thickness of 30-50um; the polyimide film is a high melting point polymer film, wherein high melting point means melting point ≥150℃.

[0020] Step S2: Select a formulation coating based on aliphatic polyurethane polymer as the material for the polymer coating; or, those skilled in the art may use other coupling compounds to improve the high adhesion and appearance requirements of the surface layer and the substrate; the coating type is not limited to solvent-based, water-based, single-component, or two-component coatings.

[0021] Step S3: Apply the coating from step S2 onto the substrate using a 90# ​​wire rod, place it in a 100°C forced-air oven for 5 minutes, and then cure it at 230°C to obtain a high-temperature resistant decorative film A for automotive exteriors.

[0022] In further preferred embodiments, a wide variety of colors and surface appearances can be achieved by adding pigments, fillers, and polymer (resin) types.

[0023] This embodiment provides a paint-free treatment process for automotive exterior parts. The process uses a high-temperature resistant decorative film A for automotive exterior parts, prepared using the method described in Example 1. This film is then laminated or bonded to the metal substrate of the automotive interior and exterior parts via online lamination or bonding. The resulting roll and flat materials are then subjected to stamping, rolling, and high-temperature co-extrusion molding processes. This process is particularly suitable for paint-free automotive exterior parts and other chemical treatment procedures. Treatment method: After lamination, a high-gloss black coating is applied using a 90# ​​wire rod, dried at 100°C for 2 minutes, and then placed at 230°C for 3 minutes.

[0024] For testing purposes, a high-temperature resistant decorative film A for automotive exteriors is applied to the surface of 304 stainless steel. After lamination and composite process, a high-gloss black coating is applied using a 90# ​​wire rod. After drying at 100℃ for 2 minutes, it is placed at 230℃ for 3 minutes to obtain test sample A.

[0025] Based on the above test sample A, the following test is conducted, which is designated as test sample A: (1) Bond strength test: The test method shall be carried out in accordance with QJ / GAC 1240.055-2022.

[0026] (2) Corrosion resistance test: The medium spray salt test shall be conducted in accordance with GB / T 10125, and the test time shall be 480h.

[0027] (3) High weather resistance test: Performed according to the conditions of (1) in GB / T16422.2-2014.

[0028] (4) High temperature resistance test: Place the sample to be tested in an environment of 250℃ for 2 minutes and observe the surface changes. Example 2

[0029] This embodiment provides a method for preparing a high-temperature resistant decorative film for automotive exteriors, the specific steps of which are as follows: Step S1: Select a polyimide film with a thickness of 10um~200um as the substrate, preferably with a substrate thickness of 50um; the polyimide film is a high melting point polymer film, wherein high melting point means melting point ≥150℃.

[0030] Step S2: Select a formulation coating based on silicon-modified polyester polymer as the material for the polymer coating.

[0031] Step S3: Roller-coating a polyester polymer onto the substrate surface to obtain a pretreated substrate.

[0032] Step S4: Apply the coating from step S2 onto the pretreated substrate using a 90# ​​wire rod, place it in a 100°C forced-air oven for 5 minutes, and then cure it at 230°C to obtain a high-temperature resistant decorative film B for automotive exteriors.

[0033] In further preferred embodiments, a wide variety of colors and surface appearances can be achieved by adding pigments, fillers, and polymer (resin) types.

[0034] This embodiment provides a paint-free treatment process for automotive exterior components. The process utilizes the high-temperature resistant decorative film B for automotive exteriors prepared in Example 3. This film is applied to the metal substrate of the automotive interior and exterior components via online lamination or bonding. The resulting roll and flat materials are then subjected to stamping, rolling, and high-temperature co-extrusion molding processes. This process is particularly suitable for paint-free automotive exterior components and other chemical treatment procedures. Treatment method: After lamination, a high-gloss black coating is applied using a 90# ​​wire rod, dried at 100°C for 2 minutes, and then placed at 230°C for 3 minutes.

[0035] For testing purposes, a high-temperature resistant decorative film B, specifically designed for automotive exteriors, is applied to the surface of 304 stainless steel. After lamination and composite processes, a high-gloss black coating is applied using a 90# ​​wire rod. The film is then dried at 100°C for 2 minutes and placed at 230°C for 3 minutes to obtain test sample B.

[0036] Based on the above test sample B, the following test is conducted, which is designated as test sample B: (1) Bond strength test: The test method shall be carried out in accordance with QJ / GAC 1240.055-2022.

[0037] (2) Corrosion resistance test: The medium spray salt test shall be conducted in accordance with GB / T 10125, and the test time shall be 480h.

[0038] (3) High weather resistance test: Performed according to the conditions of (1) in GB / T16422.2-2014.

[0039] (4) High temperature resistance test: Place the sample to be tested in an environment of 250℃ for 2 minutes and observe the surface changes. Example 3

[0040] This embodiment provides a method for preparing a high-temperature resistant decorative film for automotive exteriors, the specific steps of which are as follows: Step S1: Select a polyimide film with a thickness of 10um~200um as the substrate, preferably with a substrate thickness of 36um; the polyimide film is a high melting point polymer film, wherein high melting point means melting point ≥150℃.

[0041] Step S2: Select a formulation coating based on silicon-modified polyester polymer as the material for the polymer coating.

[0042] Step S3: Roller-coating a polyester polymer onto the substrate surface to obtain a pretreated substrate.

[0043] Step S4: Apply the coating from step S2 onto the pretreated substrate using a 90# ​​wire rod, place it in a 100°C forced-air oven for 5 minutes, and then cure it at 230°C to obtain a high-temperature resistant decorative film C for automotive exteriors.

[0044] In further preferred embodiments, a wide variety of colors and surface appearances can be achieved by adding pigments, fillers, and polymer (resin) types.

[0045] This embodiment provides a paint-free treatment process for automotive exterior parts. The process utilizes the high-temperature resistant decorative film C for automotive exterior parts prepared in Example 5. This film is applied to the metal substrate of the automotive interior and exterior parts via online lamination or bonding. The resulting roll and flat materials are then subjected to stamping, rolling, and high-temperature co-extrusion molding processes. This process is particularly suitable for paint-free automotive exterior parts and other chemical treatment processes. Treatment method: After lamination, a high-gloss black coating is applied using a 90# ​​wire rod, dried at 100°C for 2 minutes, and then placed at 230°C for 3 minutes.

[0046] For testing purposes, a high-temperature resistant decorative film C, specifically designed for automotive exteriors, is applied to the surface of 304 stainless steel. After lamination and composite processes, a high-gloss black coating is applied using a 90# ​​wire rod. The film is then dried at 100°C for 2 minutes and placed at 230°C for 3 minutes to obtain test sample C.

[0047] Based on the above test sample C, the following test is conducted, which is designated as test sample C: (1) Bond strength test: The test method shall be carried out in accordance with QJ / GAC 1240.055-2022.

[0048] (2) Corrosion resistance test: The medium spray salt test shall be conducted in accordance with GB / T 10125, and the test time shall be 480h.

[0049] (3) High weather resistance test: Performed according to the conditions of (1) in GB / T16422.2-2014.

[0050] (4) High temperature resistance test: Place the sample to be tested in an environment of 250℃ for 2 minutes and observe the surface changes.

[0051] Example for comparison: The test comparison table for test cases A, B, and C is shown in Table 1 below:

[0052] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0053] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-temperature resistant decorative film for automotive exteriors, characterized in that, The preparation process includes, from the inside out, a substrate layer (1), an interface layer (2), and a surface layer (3), and also includes the following preparation steps: S1: The substrate layer (1) is a high-melting-point polymer film as the substrate; S2: Apply an interface layer (2) to the outside of the substrate layer (1); S3: Apply a coating layer (3) to the outside of the interface layer (2).

2. The method for preparing a high-temperature resistant decorative film for automotive exteriors according to claim 1, characterized in that, The substrate layer (1) is any one of polyamide compounds, fluoropolymers, polyether ether ketones, polyimides, polyethylene terephthalate, and polyphenylene sulfide.

3. The method for preparing a high-temperature resistant decorative film for automotive exteriors according to claim 1, characterized in that, The substrate layer (1) has a melting point ≥150℃.

4. The method for preparing a high-temperature resistant decorative film for automotive exteriors according to claim 1, characterized in that, The coating thickness of the substrate layer (1) is 10um~200um.

5. The method for preparing a high-temperature resistant decorative film for automotive exteriors according to claim 1, characterized in that, The interface layer (2) is composed of epoxy polymers, polyurethane polymers and silicone polymers.

6. The method for preparing a high-temperature resistant decorative film for automotive exteriors according to claim 1, characterized in that, The surface layer (3) is composed of one or more of aliphatic polyurethane polymers, acrylic polymers, silicone-modified polyester polymers, and fluoropolymers.

7. A paint-free treatment process for automotive exterior parts, characterized in that, The high-temperature resistant decorative film for automotive exteriors, prepared by the method described in any one of claims 1 to 9, is then laminated or bonded to the metal substrate of automotive interior and exterior components via online application.

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