A self-adhesive polyolefin automotive paint color-changing protective film and its manufacturing equipment

Abstract

This utility model discloses a self-adhesive polyolefin automotive paint color-changing protective film and its manufacturing equipment, aiming to solve the problems of high cost, poor weather resistance, and difficult air venting during construction of existing color-changing films. The protective film adopts a multi-layer composite structure, including an adhesive layer, a base color layer, a colored layer, a scratch-resistant layer, and a protective PET film layer from the inside out. The core layer material is a blend of polypropylene (PP) or polyethylene (PE) and hydrogenated styrene block elastomer (SEBS / SEPS), and functional additives are added to improve scratch resistance and weather resistance. The manufacturing equipment includes a four-layer co-extrusion casting system, a PET film synchronous lamination device, and a cooling and shaping mechanism. The four-layer co-extrusion process achieves continuous material lamination, and combined with a textured release film or inorganic microsphere air venting design, production costs are reduced while product performance is improved. This color-changing film has a scratch resistance of 15N and passes the UV aging test for 1500 hours, making it widely applicable to automotive paint color-changing and protection scenarios.

Description

Technical Field

[0001] This utility model belongs to the field of automotive protective materials technology, and in particular relates to a self-adhesive polyolefin automotive paint color-changing protective film and its manufacturing equipment. Background Technology

[0002] As Chinese car culture gradually takes root, car color changing is becoming a popular modification option. Combining colored car bodies with protective films creates a unique style and highlights individuality, which will undoubtedly play a significant role in boosting car sales.

[0003] Currently, car color-changing films are not yet widespread, and many people consider them to be high-end products. The purpose of this utility model patent is to make the polyolefin car paint color-changing protective film both beautiful and economical, so that consumers will be willing to accept it.

[0004] Consumers have a need for self-adhesive car wrapping films that can be changed to other colors in a short period of time without damaging the original paint. It's understood that many car owners change their wraps three times a year, or even more. Currently, TPU car wrapping films are expensive and difficult to popularize, while PVC car wrapping films, although cheaper, are prone to aging, making them less appealing to car owners.

[0005] Chinese patent CN216466684U relates to a TPU multi-layer color-changing car wrap, comprising a protective layer, a multi-layer effect color-changing layer, a TPU transparent base layer, and an adhesive layer, arranged sequentially from top to bottom. The protective layer includes a release protective layer and a multi-functional protective layer. The TPU transparent base layer uses TPU as the substrate layer, giving it good light transmission, flexibility, and shrinkage. The adhesive layer includes an adhesive layer and an anti-stick layer. This patent can achieve beneficial effects such as multi-layer color changing, distinct visual layers, and easy application. However, its use of TPU material as the transparent base layer results in a high product price. In addition, its multi-layer processing technology uses a technique of coating each layer on the TPU base layer, which is an outdated process. The coated adhesive layer is prone to peeling off, and the processing environment requires chemical solvents, making the process environmentally unfriendly. Utility Model Content

[0006] To address the aforementioned technical issues, the research and development direction of this utility model protective film is to create a novel self-adhesive polyolefin automotive paint protection film that is competitively priced with PVC automotive color-changing films and comparable in quality to TPU automotive color-changing films. The manufacturing equipment for this utility model achieves continuous material composite through a four-layer co-extrusion casting process, combined with a textured release film or inorganic microsphere venting design, reducing production costs while improving product performance.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by this utility model is as follows:

[0008] A self-adhesive polyolefin automotive paint color-changing protective film includes a multi-layer structure stacked sequentially from the inside out. The multi-layer structure includes at least four core functional layers, which, from the inside out, are:

[0009] Adhesive layer, used for bonding to the car paint surface;

[0010] The base color layer is located outside the adhesive layer;

[0011] The colored layer is located outside the base color layer;

[0012] A scratch-resistant layer is located outside the colored layer;

[0013] The four core functional layers are integrally formed by co-extrusion process, with each layer arranged sequentially along the thickness direction and composite without gaps.

[0014] Furthermore, the multilayer structure also includes a protective PET film layer, which is located outside the scratch-resistant layer and is bonded to the scratch-resistant layer.

[0015] Furthermore, the multilayer structure also includes a textured release film layer, which is located inside the adhesive layer, and the surface of the textured release film layer is provided with a textured surface.

[0016] Furthermore, the textured release film layer is made of PET material, and the mesh count of the textured surface is 500-2000 mesh.

[0017] Furthermore, the adhesive layer has a thickness of 20–30 μm, and inorganic microspheres are distributed within the adhesive layer, with a particle size of 5–30 μm.

[0018] Furthermore, the total thickness of the four core functional layers is 80–130 μm, wherein:

[0019] The thickness of the adhesive layer is 20–30 μm;

[0020] The thickness of the base color layer is 20–35 μm;

[0021] The thickness of the colored layer is 20–35 μm;

[0022] The thickness of the scratch-resistant layer is 20–30 μm.

[0023] An apparatus for manufacturing the self-adhesive polyolefin automotive paint color-changing protective film, comprising:

[0024] An extrusion system comprising four extruders, the discharge ends of which are connected to the same co-extrusion die via screws;

[0025] The co-extrusion die includes a multi-layer distribution channel and a four-layer co-extrusion flat die head, wherein the multi-layer distribution channel is connected to the four extruders in a one-to-one correspondence;

[0026] The cooling and shaping mechanism includes a first cooling roller and a second cooling roller arranged sequentially along the protective film forming direction. The first cooling roller is a mirror roller, and the second cooling roller is an anti-sticking roller.

[0027] A PET film laminating device includes at least one pressure cylinder and a pressure roller, the pressure roller being used to press a PET film onto a protective film surface;

[0028] The edge trimming and winding device includes a traction roller and a take-up roller, and a tension adjustment mechanism is provided between the traction roller and the take-up roller.

[0029] Furthermore, the surface of the first cooling roller is chrome-plated and polished, and the surface of the second cooling roller is sprayed with an anti-stick coating. The surface temperature of the first cooling roller and the second cooling roller is 10-30°C.

[0030] Furthermore, the inner diameter of the pressure cylinder of the PET film composite device is 120mm, and the unit pressure of the pressure roller can be adjusted to 0.6-1MPa.

[0031] Furthermore, the edge-cutting and winding device integrates a tension sensor closed-loop feedback system, which achieves dynamic tension adjustment through PLC, servo drive and PID algorithm, with a winding tension of 50-100N.

[0032] Furthermore, the equipment also includes a twin-screw extruder for pre-granulation of the adhesive layer material to prevent the mixture from clogging at the hopper inlet of the single-screw extruder.

[0033] The beneficial effects achieved by this utility model are as follows:

[0034] 1. Cost and performance balance: The PP / PE and SEBS / SEPS blend system replaces the expensive TPU and the easily aged PVC, reducing the cost by more than 30%, while the tensile strength is ≥25MPa and the elongation is >500%, meeting the mechanical performance requirements of automotive protective films.

[0035] 2. Ultra-long aging resistance life: Through the synergistic effect of UV absorbers, light stabilizers and antioxidants, combined with the UV blocking effect of white masterbatch titanium dioxide, the aging resistance life is ≥5 years.

[0036] 3. Excellent scratch resistance: The scratch-resistant layer contains 5% to 10% scratch-resistant agent and passes the 15N five-finger scratch test.

[0037] 4. High-efficiency exhaust and construction adaptability: The exhaust design uses textured PET film or inorganic microspheres, and there are no air bubbles left during water spraying / hot air construction. The peel force is 10-12N / 25mm, and there is no adhesive residue.

[0038] 5. The base coat and color coat have a Shore A hardness of less than 90, ensuring a firm bond at the edges of the automotive paint without peeling off.

[0039] 6. Environmental protection and process stability: The solvent-free co-extrusion casting process achieves zero VOC emissions, and the cooling temperature ≤130℃ ensures that the PET film is not deformed.

[0040] 7. Color diversity and appearance texture: By combining a base color layer (low saturation) with a color layer (high saturation), matte, pearlescent, and metallic colors can be achieved, balancing color vibrancy and stability. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the six-layer structure of the self-adhesive polyolefin automotive paint color-changing protective film of Embodiment 1 of this utility model.

[0042] Figure 2 This is a schematic diagram of the four-layer co-extrusion composite process of the self-adhesive polyolefin automotive paint color-changing protective film of Embodiment 1 of this utility model.

[0043] Figure 3 This is a top view of the four-layer co-extrusion composite equipment for the self-adhesive polyolefin automotive paint color-changing protective film of Embodiment 1 of this utility model.

[0044] In the picture:

[0045] 1. Textured release film layer; 2. Adhesive layer; 3. Base color layer; 4. Colored layer; 5. Scratch-resistant layer; 6. Protective PET film layer; 7. Extruder; 8. Screw; 9. Four-layer co-extrusion flat die head; 10. Co-extrusion die; 11. Point B; 12. Point A; 13. Anti-stick roller; 14. Mirror roller; 15. First guide roller; 16. PET film unwinding roller; 17. Second guide roller; 18. PET textured film or textured paper unwinding roller; 19. PET textured film pressure roller; 20. Third guide roller; 21. Vacuum equipment; 22. Cooling air knife; 23. Take-up roller; 24. Traction roller; 25. Feed hopper; 26. Distributor. Detailed Implementation

[0046] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not all features. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0047] In this document, the term "embodiment" means that a particular feature, method, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] The self-adhesive polyolefin automotive paint color-changing protective film disclosed in this utility model is prepared by a multi-layer co-extrusion casting process. The specific method steps and parameters are described in detail below:

[0049] 1. Material Preparation

[0050] 1.1. Substrate and Elastomer:

[0051] Polypropylene (PP): Select F800E, F800EDF or F800F with a melt flow rate (MFR) of 5-10 g / 10 min (230℃, 2.16 kg);

[0052] The F800EDF is a copolymer PP used to enhance flexibility in the base color layer, while the F800E / F is a homopolymer PP used to ensure strength in the functional layer. The two work together to form a synergistic effect in the composite structure.

[0053] Polyethylene (PE): Linear polyethylene 7042, metallocene polyethylene 2010HA or MLLDPE 8415 can be selected as blending components for PP;

[0054] The 7042 is a linear low-density PE used for base color layers and color layers. It is characterized by low cost and is suitable for conventional colors and general scenarios.

[0055] The 2010HA and MLLDPE 8415 are metallocene linear low-density PEs used for scratch-resistant layers and highly weather-resistant protective films. They have high tensile strength and excellent puncture resistance, making them suitable for high-end vehicles or long-term outdoor use.

[0056] Elastomers: SEBS (such as Corten G1657, G1645, Baling 507), SEPS (such as 7311, 2063) or POE (such as 8411, 2060, 6102), wherein the Shore A hardness of the elastomer is 30 to 40.

[0057] The SEBS is a hydrogenated styrene block elastomer, including: Kerté G1657 and Baling 507, used for the adhesive layer, base layer, and color layer, and has the characteristics of excellent weather resistance, viscosity adjustment, and low-temperature flexibility.

[0058] The SEPS is a hydrogenated styrene-isoprene block elastomer, including 7311 and 2063, used in colored layers and scratch-resistant layers, and features high transparency, resistance to yellowing, and good compatibility with color masterbatches.

[0059] The POE is a polyolefin elastomer, including 8411, 2060, and 6102, used for the base color layer and scratch-resistant layer, and has the characteristics of excellent processing fluidity, low cost, and excellent compatibility with PP / PE.

[0060] The term POE refers to polyolefin elastomers with an octene content exceeding 20%, while polyolefin elastomers with an octene content less than or equal to 20% are referred to as POP.

[0061] The elastomer accounts for 15% to 25% of the mass of the base color layer, and the mass ratio of PP to elastomer is 1.5 to 3.

[0062] 1.2. Functional additives:

[0063] Scratch-resistant agents: SR100B, KM-1 or SD-199 (addition amount 5-10%);

[0064] Anti-aging additives: UV absorber 531 (less than 1%), light stabilizer 2020 (less than 0.5%), antioxidant 1010 (less than 0.5%);

[0065] Penetration enhancer: HPN20E (addition amount ≤0.3%);

[0066] Microspheres: Transparent inorganic microspheres (particle size 5-30μm, addition amount ≤0.5%).

[0067] 1.3. Masterbatch:

[0068] White masterbatch (titanium dioxide content 65%, addition amount 10-20%);

[0069] Color masterbatch (high / low saturation, such as red, green, yellow, and blue; the amount added should be adjusted according to the supplier's recommended ratio).

[0070] 1.4. PET film:

[0071] Textured PET release film (500-2000 mesh, 120μm thickness);

[0072] Protective PET film (50μm thick, double-sided release or single-sided glossy).

[0073] 2. Preparation process

[0074] 2.1. Blending and granulation:

[0075] Add PP / PE, elastomer, color masterbatch and additives to a high-speed mixer in proportion and mix for 10-15 minutes until uniform;

[0076] Select a single or twin-screw extruder for granulation based on the characteristics of the granules. The adhesive layer material must be granulated using a twin-screw extruder with an extrusion temperature of 160–190℃ and a rotation speed of 300–400 rpm to obtain specialized granules for each layer.

[0077] 2.2. Multilayer co-extrusion casting:

[0078] Using a four-layer co-extrusion casting machine (die width 2000mm), the temperature settings for each extruder are as follows:

[0079] First layer (adhesive layer): 155~165℃;

[0080] Third / fourth layer (color masterbatch layer): 170~180℃;

[0081] Fifth layer (scratch-resistant layer): 180~190℃;

[0082] Melt flow rate control: The MFR of each layer is maintained at 5-6 g / 10 min (190℃, 2.16 kg), and the flow rate is matched by adjusting the screw speed;

[0083] Lamination process: PET textured film and protective PET film are laminated on a mirror roller (the protective film temperature is 60-80℃ after cooling by the mirror roller). The lamination temperature is ≤130℃ to avoid PET deformation.

[0084] 2.3. Trimming and winding:

[0085] After the cast film is stretched by the traction roller (stretch ratio 1.05 to 1.3), it is cut into rolls with a width of 1.52m and a winding tension of 50 to 80N.

[0086] 3. Implementation of the exhaust scheme

[0087] 3.1. Option 1: Adding microbeads

[0088] Add 0.3% to 0.5% inorganic microspheres (particle size 5 to 30 μm) to SEBS / SEPS hot melt pressure-sensitive adhesive, and mix evenly by twin-screw extrusion to obtain microsphere-containing adhesive granules;

[0089] The thickness of the adhesive layer is controlled at 20-30μm. When applying the film, the microbeads form tiny channels on the surface of the adhesive layer, which can quickly expel air when used with a felt scraper.

[0090] 3.2. Option 2: Textured PET Composite

[0091] In the four-layer co-extrusion casting process, a 120μ thick, 500-2000 mesh textured PET release film is laminated with an adhesive layer, with the textured side facing the adhesive layer;

[0092] The composite pressure is 0.3-0.5 MPa, and the cooling roller temperature is 70℃, to ensure that the mesh structure is completely transferred to the adhesive surface.

[0093] 4. Performance Testing Methods

[0094] 4.1. Mechanical properties: Tensile strength (≥25MPa) and elongation (>500%) shall be tested according to GB / T 1040.3;

[0095] 4.2. Weather resistance: The UVA-340 aging test (1500 hours) was conducted according to GB / T 16422.3, and the performance change rate was <10%.

[0096] 4.3. Scratch resistance: After 100 scratches using a five-finger scratch tester (load 15N), no obvious scratches were observed.

[0097] 4.4. Peel strength: The peel strength to automotive paint is tested according to GB / T 2792 (>10N / 25mm), and there is no residue.

[0098] Example 1

[0099] The self-adhesive polyolefin automotive paint color-changing protective film in Example 1 is a six-layer structure red high-saturation color-changing protective film, and the film application is carried out using a hot air film application process.

[0100] like Figure 1 As shown, the materials and thicknesses of each layer of the six-layer red high-saturation color-changing protective film are as follows:

[0101] The sixth layer is a protective PET film layer 6, the material of which is PET, and the thickness of which is 50μm;

[0102] The fifth layer is a scratch-resistant layer 5, which is made of PP F800E + POP8411 ​​+ SR100B scratch-resistant agent + light stabilizer 2020, and has a thickness of 25μm.

[0103] The fourth layer is a colored layer 4, which is made of PP F800E+POE8411+red masterbatch+light stabilizer 2020, and has a thickness of 30μm.

[0104] The third layer is the base color layer 3, which is made of PP F800EDF + POE8411 + white masterbatch + light stabilizer 2020, with SEBS accounting for 20%, and the thickness of the base color layer 3 is 30μm.

[0105] The second layer is adhesive layer 2, the material of adhesive layer 2 is SEBS G1657+C5 tackifier, and the thickness of adhesive layer 2 is 25μm;

[0106] The first layer is a textured release film layer 1, which is a 500-2000 mesh PET textured release film with a thickness of 120 μm.

[0107] The self-adhesive polyolefin automotive paint color-changing protective film of Example 1 uses a manufacturing equipment, such as... Figure 2 , Figure 3 As shown, it includes: an extrusion system, a co-extrusion die, a cooling and shaping mechanism, a film unwinding device, a PET film laminating device, a defect detection device, and an edge trimming and winding device;

[0108] The extrusion system includes four single-screw extruders 7, corresponding to the melt extrusion of the adhesive layer 2, base color layer 3, color layer 4, and scratch-resistant layer 5 materials, respectively. The discharge port of each extruder 7 is connected to the co-extrusion die 10. One end of each extruder 7 is connected to the feeding hopper 25, and the other end is connected to the distributor 26 through the screw 8. The distributor 26 is connected to the four-layer co-extrusion flat die head 9. The adhesive layer adopts a special pretreatment equipment: the special pretreatment equipment refers to the adhesive layer material being granulated by a twin-screw extruder before use, which is independent of the four single-screw extruders, to avoid material blockage when using the mixture directly. The granulation temperature is 160-180℃ to ensure that SEBS / SEPS and the thickener are evenly dispersed.

[0109] The co-extrusion die employs a multi-layer distribution channel designed by computer simulation, with a die lip width of 2000 mm and a temperature control of 180–190 °C. Channel optimization ensures that the melt flow rate (MFR) deviation of each layer is ≤5%, and the total film thickness deviation is controlled within 1–2% (MFR = 5–6 g / 10 min at 190 °C and 2.16 kg). The co-extrusion mechanism of the co-extrusion die is a four-layer co-extrusion flat die head 9 with a built-in 1000-mesh tubular filter to effectively control crystal points (≤3 crystal points per square meter of 0.5 mm).

[0110] The cooling and shaping mechanism includes a first cooling roller (mirror roller 14) and a second cooling roller (anti-stick roller 13), both with surface temperatures controlled between 10 and 30°C (to prevent condensation); the mirror roller 14 has a diameter of 400 mm and a chrome-plated and polished surface; the anti-stick roller 13 has a Teflon-coated surface and a diameter of 300 mm.

[0111] The film unwinding mechanism includes a PET film unwinding roller 16 and a first guide roller 15, which are disposed above the first cooling roller (mirror roller 14) and are used to simultaneously release the textured PET release film and the protective PET film. The unwinding tension is 50-60N.

[0112] The PET film laminating device includes a PET textured film pressure roller 19, which provides a unit pressure of 0.6 to 1 MPa through a pressure cylinder with an inner diameter of 120 mm, and simultaneously laminates a protective PET film (sixth layer) and a textured release film (first layer); the textured release film is a 500-2000 mesh PET film, and the PET textured film pressure roller 19 ensures that the textured structure is completely transferred to the adhesive layer surface.

[0113] The edge trimming and winding device includes a take-up roller 23, a traction roller 24, and a third guide roller 20. The traction roller 24 provides traction and is guided to the take-up roller 23 via the third guide roller 20. The edge trimming and winding device integrates a tension sensor closed-loop feedback system, which integrates PLC, servo drive, and PID algorithm. Dynamic adjustment is achieved through recursive calculation of roll diameter and torque compensation. The winding tension is 80-100N, and the traction speed is 10-15m / min, ensuring smooth winding.

[0114] The defect detection device is a high-precision image processing system that uses transmitted / reflected light to illuminate the thin film surface and acquires images through a line scan camera. It can detect defects (such as crystal points and bubbles) with a diameter ≥0.01mm, and the detection data is stored in real time.

[0115] The equipment adopts a T-shaped layout: the film unwinding device and the PET film laminating device are respectively located on both sides of the cooling and setting mechanism, and the extrusion system and co-extrusion die are located above the cooling and setting mechanism, together forming a T-shaped layout; the mirror roller 14 and the anti-stick roller 13 are below the four-layer co-extrusion die head 9, the take-up roller 23 of the final product is on the far left, the traction roller 24 is in the middle position between the take-up roller 23 and the anti-stick roller 13, the PET textured film pressure roller 19 is to the lower left of the mirror roller 14, and the non-textured PET film... The unwinding roller 16 is located to the right of the mirror roller 14. The edge material generated by the core four-layer co-extruded film is wound up and stored separately by the edge trimming device. In addition, there is a vacuum device 21 between the core four-layer co-extruded film and the PET film, and a cooling air knife 22 is located on the upper left of the mirror roller 14. The four extruders 7 are combined together and share a four-layer co-extruded flat die head 9, which is arranged in a T-shape with the cooling unwinding device. This together forms a T-shaped layout, which solves the space limitation problem of traditional casting equipment and realizes the synchronous lamination of multi-layer protective films and optimized venting.

[0116] The manufacturing process of a six-layer red high-saturation color-changing protective film using the aforementioned manufacturing equipment in Example 1 is briefly described below:

[0117] like Figure 2As shown, the key equipment in the processing technology is a four-layer co-extrusion casting molding equipment, which includes four extruders 7, each a single-screw extruder, corresponding to four layers of material. These four layers correspond to the second layer (hot melt pressure-sensitive adhesive layer), the third layer (white / low-saturation masterbatch layer), the fourth layer (colored masterbatch layer), and the fifth layer (scratch-resistant layer). The adhesive layer employs a dedicated pretreatment process: this dedicated pretreatment process refers to the adhesive layer material being granulated first by a twin-screw extruder, using an underwater die granulation process, independent of the four single-screw extruders, to avoid material blockage when directly using the mixture; the granulation temperature is 160–180℃ to ensure uniform dispersion of the elastomer and tackifier; the four extruders 7… The discharge port is connected to the co-extrusion die 10 via the screw 8, and is used to extrude the molten PP / PE, SEBS / SEPS / POP / POE, masterbatch and additive mixture in proportion. The co-extrusion die 10 adopts a multi-layer distribution channel design, which integrates four layers of melt into one, with a die lip width of 2000mm and a temperature control of 170~190℃. It is extruded through the four-layer co-extrusion flat die head 9 to the surface of the sixth protective PET film layer 6 driven by the mirror roller 14. When the mirror roller 14 is driven to point A 11, it is cooled and squeezed by the cooling air knife 22. When it rotates to point B 12, it is covered and squeezed by the first layer of mesh release film layer 1 driven by the PET mesh film pressure roller 19, forming a six-layer composite protective film. The minimum distance between point A and point B is 400mm.

[0118] The sixth protective PET film layer 6 is released by the PET film unwinding roller 16 and driven by the first guide roller 15 to the mirror roller 14. The mirror roller 14 drives the sixth protective PET film layer 6 to the four-layer co-extrusion die 9. Here, a vacuum device 21 evacuates the surface of the sixth protective PET film layer 6 before it enters the four-layer co-extrusion die 9 to extrude four layers of melt. Vacuuming between the four-layer co-extruded film and the PET film eliminates gaps between them, which is beneficial for improving the flatness of the film. Under vacuum, it is squeezed and driven by the mirror roller 14 and combined with the four-layer melt. The mirror roller 14 is the first cooling roller, which simultaneously performs initial cooling on the protective film formed by the four-layer melt and the protective PET film layer 6. The temperature of the protective film after being cooled by the mirror roller 14 is 60-80℃.

[0119] The first layer of anilox release film 1 is released by the PET anilox film or anilox paper unwinding roller 18 and guided by the second guide roller 17 to the PET anilox film pressure roller 19. The PET anilox film pressure roller 19 provides a unit pressure of 0.6 to 1 MPa through a pressure cylinder with an inner diameter of 120 mm, and simultaneously laminates the protective PET film (sixth layer) and the anilox release film (first layer) on the mirror roller 14. The anilox release film is a 500-2000 mesh PET film, and the PET anilox film pressure roller 19 ensures that the anilox structure is completely transferred to the adhesive layer surface.

[0120] The anti-stick roller 13 is the second cooling roller. The temperature of the protective film after being cooled by the anti-stick roller 13 is 25-30℃. The six-layer protective film is cooled again by the anti-stick roller 13 and pulled by the traction roller 24. It is then guided by the third guide roller 20 to the take-up roller 23 to enter the edge trimming and winding process. The width of the edge trimming roll is 1.52m, and the curing time is not less than 24 hours. After passing through the traction and winding device, the traction, edge trimming and winding of the protective film are completed, and finally a finished product of a six-layer red high-saturation color-changing protective film is formed.

[0121] The manufacturing method of the six-layer red high-saturation color-changing protective film of Example 1 includes the following steps:

[0122] 1. Material Preparation

[0123] Fifth layer (scratch-resistant layer 5): Mix polypropylene F800E (70%), POP8411 ​​(23%), SR100B scratch-resistant agent (5%), and light stabilizer 2020 (2%) by mass ratio, stir evenly, and then add to the extruder hopper.

[0124] Fourth layer (color layer 4): Mix F800E (68%), POE8411 (30%), red masterbatch (2%), and light stabilizer 2020 (2%), stir evenly, and then add to the extruder hopper.

[0125] The third layer (base color layer 3): Mix F800EDF (63%), POE8411 (25%), white masterbatch (10%, titanium dioxide concentration 65%), and light stabilizer 2020 (2%), stir evenly, and then add to the extruder hopper.

[0126] Second layer (adhesive layer 2): Kronen SEBS G1657 (60%) + C5 resin (40%), mix evenly and add to the extruder hopper.

[0127] 2. Four-layer co-extrusion casting film

[0128] Using a 2000mm wide four-layer co-extrusion casting machine, the temperatures of each layer were set as follows: second layer (adhesive layer 2) 160℃, third layer (base color layer 3) 180℃, fourth layer (color layer 4) 180℃, and fifth layer (scratch-resistant layer 5) 190℃.

[0129] The thickness of the film layers after extrusion lamination is as follows: second layer (adhesive layer 2) 25μ, third layer (base color layer 3) 30μ, fourth layer (colored layer 4) 30μ, fifth layer (scratch-resistant layer 5) 25μ, and the total thickness is 110μ.

[0130] 3. PET film lamination and venting

[0131] On mirror roller 14 (cooled temperature 60-80℃), the co-extruded film is laminated with a 120μ mesh PET release film (mesh count 500-2000 mesh), and a 50μ protective PET protective film layer 6 (sixth layer) is laminated simultaneously.

[0132] 4. Cooling and winding

[0133] After the protective film is cooled by the cooling roller (temperature 25-30℃ after cooling), it is wound up at a speed of 10-15m / min to obtain the finished product.

[0134] 5. Performance Testing

[0135] Tensile strength 28MPa, elongation 550%, peel force 12N / 25mm, no residue; passes UVA aging for 1500 hours and five-finger scratch test for 15N.

[0136] Example 2

[0137] Example 2 shows a self-adhesive polyolefin automotive paint color-changing protective film, which is a five-layer blue matte color-changing protective film. The film application process uses a water spraying application technique.

[0138] The materials and thicknesses of each layer of the five-layer blue matte color-changing protective film are as follows:

[0139] Fifth layer (protective PET film layer 6): 120μ double-sided release PET film;

[0140] Fourth layer (scratch-resistant layer 5): F800E + POP8411 ​​+ SR scratch-resistant agent + light stabilizer 2020, thickness 30μ;

[0141] The third layer (color layer 4): F800E+POP2060+blue masterbatch+light stabilizer 2020, thickness 35μ;

[0142] Second layer (base color layer 3): F800EDF + POE8411 + moon white masterbatch + light stabilizer UV944, thickness 35μ;

[0143] First layer (adhesive layer 2): SEBS G1645 + C5 resin + microbeads, thickness 30μ.

[0144] The manufacturing equipment for the five-layer blue matte color-changing protective film in Example 2 is basically the same as that in Example 1, except that:

[0145] 1. Co-extrusion die runner design: For the five-layer structure (without textured release film layer), the melt distribution ratio of the multi-layer distribution runner is adjusted by computer simulation to ensure that the thickness of the adhesive layer (first layer) is precisely controlled at 30μ (deviation ≤5%).

[0146] 2. PET film laminating device: Simultaneously laminates double-sided release PET film only. The unit pressure of the pressure cylinder is adjusted to 0.8-1MPa to meet the surface texture requirements of matte film.

[0147] 3. Cooling temperature optimization: The temperature of the mirror roller (14) is controlled at 25-30℃, and the temperature of the anti-stick roller (13) is 20-25℃, which is suitable for the requirements of the water spraying film application process for the flatness of the film surface.

[0148] Method for manufacturing the five-layer blue matte color-changing protective film of Example 2:

[0149] 1. Material Preparation

[0150] Fourth layer (scratch-resistant layer 5): Mix F800E PP resin (69%) + POP8411 ​​(20%), SR100B scratch-resistant agent (10%), and light stabilizer 2020 (1.0%), and stir until homogeneous.

[0151] The third layer (color layer 4): a mixture of F800E (67%) + POP2060 (30%), blue masterbatch (1.5%), and light stabilizer 2020 (1.5%).

[0152] Second layer (base color layer 3): a mixture of F800EDF (72%), POE8411 (25%), moon white masterbatch (20%), and light stabilizer UV944 (1.5%).

[0153] First layer (adhesive layer 2): Hot melt pressure-sensitive adhesive with Kron SEBS G1645 (70%) + C5 resin (29.7%) + microspheres (0.3%, 30μ) as the main components.

[0154] 2. Four-layer co-extrusion casting film

[0155] Casting machine temperature settings: first layer (adhesive layer 2) 155℃, second layer (base color layer 3) 175℃, third layer (color layer 4) 180℃, fourth layer (scratch-resistant layer 5) 185℃.

[0156] Film thickness: first layer (adhesive layer 2) 30μ, second layer (base color layer 3) 35μ, third layer (color layer 4) 35μ, fourth layer (scratch-resistant layer 5) 30μ, total thickness 130μ.

[0157] 3. PET film lamination and venting

[0158] Double-sided release PET film is simultaneously laminated on mirror roller 14 (temperature 75℃ after cooling).

[0159] 4. Cooling and winding

[0160] Rapid cooling is achieved through the anti-stick roller 13 (temperature 25℃ after cooling), with a winding speed of 10-15m / min.

[0161] 5. Performance Testing

[0162] Bubbles disappeared within 30 seconds after water spraying and film application; tensile strength was 26 MPa; elongation was 520%; UVA aging time was passed; and 12N five-finger scratching was passed.

[0163] Example 3

[0164] The self-adhesive polyolefin automotive paint color-changing protective film in Example 3 is a five-layer high weather-resistant protective film, and the film application process uses a hot air film application process.

[0165] The five-layer high-weather-resistant protective film has been adjusted for the following key materials:

[0166] The fifth layer contains 0.2% HPN20E anti-reflective agent (the amount of anti-reflective agent added is controlled below 0.3%) and KM-1 (5%) scratch-resistant agent; the scratch-resistant agent KM-1 can be replaced with SD-199;

[0167] The third / fourth layer anti-aging additives are compounded as follows: UV531 (0.3%) + light stabilizer 2020 (0.4%) + antioxidant 1010 (0.2%).

[0168] The substrate uses MLLDPE 8415 (fourth layer) and PP F800EDF (third layer).

[0169] Method for manufacturing the five-layer high weather-resistant protective film of Example 3:

[0170] 1. Material Preparation

[0171] Fifth layer (scratch-resistant layer 5): a mixture of MLLDPE 8415 (83%), SEPS7311 (10%), KM-1 scratch-resistant agent (5%), UV absorber 3346 (1.5%), antioxidant 1010 (0.3%), and transparent agent HPN20E (0.2%).

[0172] Fourth layer (color layer 4): MLLDPE 8415 (78%), SEPS7311 (20%), yellow masterbatch (1.2%), UV absorber 3346 (1.5%), antioxidant 1010 (0.3%).

[0173] The third layer (base color layer 3): MLLDPE 8415 (72%), SEPS7311 (24%), milky white masterbatch (2.2%), UV absorber 3346 (1.5%), antioxidant 1010 (0.3%).

[0174] The second layer (adhesive layer 2) is a hot melt pressure-sensitive adhesive mainly composed of Baling SEBS 507 (80%), C5 resin (19.5%), and microspheres (0.5%, 5μ).

[0175] 2. Four-layer co-extrusion casting film

[0176] Casting machine temperatures: second layer (adhesive layer 2) 165℃, third layer (base color layer 3) 170℃, fourth layer (color layer 4) 170℃, fifth layer (scratch-resistant layer 5) 180℃.

[0177] Film thickness: second layer (adhesive layer 2) 20μ, third layer (base color layer 3) 20μ, fourth layer (color layer 4) 20μ, fifth layer (scratch-resistant layer 5) 20μ, total thickness 80μ.

[0178] 3. PET film lamination and venting

[0179] Simultaneous lamination of double-sided release PET film, followed by pressing with cooling rollers.

[0180] 4. Cooling and winding

[0181] It adopts dual-roll cooling (front roll surface temperature 30℃, rear roll surface temperature 20℃) and winding tension 50N.

[0182] 5. Performance Testing

[0183] 95% gloss, 1.2% haze; passed 1500 hours of UVA aging, peel strength 11N / 25mm, no residue.

[0184] Comparative Example 1

[0185] The protective film in Comparative Example 1 is a five-layer structure without scratch-resistant agent, and the film application process uses a hot air application technique.

[0186] The fifth layer material of Comparative Example 1: PP F800F + POE6102 (without scratch-resistant agent), with 0.2% light stabilizer 2020 added;

[0187] The manufacturing process of Comparative Example 1 is as follows:

[0188] 1. Material Preparation

[0189] Fifth layer: F800F (99.7%), POE6102 (0.1%), light stabilizer 2020 (0.2%) (no scratch resistant agent).

[0190] Fourth layer: F800F (98%), POE6102 (1.8%), blue masterbatch (0.2%), light stabilizer 2020 (0.2%).

[0191] Third layer: F800EDF (97%), POE6102 (2.8%), white masterbatch (0.2%), light stabilizer 2020 (0.2%).

[0192] Second layer: SBS YH796 (60%), C5 / C9 copolymer resin (40%) (without degassing microbeads or textured film).

[0193] 2. Four-layer co-extrusion casting film

[0194] The casting temperature is 170℃ (consistent across all layers), and the total thickness is 110μ (30μ for the second layer).

[0195] 3. Lamination and winding

[0196] Direct lamination with non-textured PET release film, cooling temperature 140℃ (exceeding the upper limit will cause PET deformation).

[0197] 4. Performance Testing

[0198] Residual adhesive is produced after applying the film with hot air; the elongation at break decreases by 60% after 800 hours of UVA aging; scratches appear after rubbing with five fingers at 5N.

[0199] The performance test results of the protective film in Comparative Example 1 showed that obvious scratches appeared after five-finger scratching at 5N, the gloss decreased by 30% after 800 hours of UVA aging, and the residual adhesive test was positive.

[0200] The second layer of SBS elastomer in Comparative Example 1, without the addition of scratch-resistant agent and with only 0.2% light stabilizer, resulted in the failure of residual adhesive and aging resistance.

[0201] Comparative Example 2

[0202] Comparative Example 2 uses a five-layer protective film without scratch-resistant agent, and the film application process employs a water spraying application technique.

[0203] The manufacturing process of Comparative Example 2 is as follows:

[0204] 1. Material Preparation

[0205] Fifth layer: LLDPE7042 (97.5%), KM-1 (2%), UV absorber 3346 (0.2%), antioxidant 1010 (0.1%).

[0206] Fourth layer: F800EDF (95%), POE6102 (4.7%), red masterbatch (0.1%), UV absorber 3346 (0.2%).

[0207] Third layer: F800EDF (95%), POE6102 (4.7%), white masterbatch (0.1%), UV absorber 3346 (0.2%).

[0208] Second layer: Baling SEBS 507 (30%), SIS1105 (30%), C5 resin (40%) (microbead addition of 0.8% exceeds the upper limit).

[0209] 2. Four-layer co-extrusion casting film

[0210] Casting temperature 165℃, total thickness 120μ (second layer 35μ exceeding the upper limit).

[0211] 3. Lamination and winding

[0212] Composite 3000 mesh textured PET film (excessive mesh count causes blockage of the exhaust channel).

[0213] 4. Performance Testing

[0214] After water spraying and applying the film, the bubble residue rate was 30%; after 600 hours of UVA aging, the yellowing ΔE = 5.2; permanent scratches appeared after five-finger scratching at 8N; and adhesive residue remained on the paint surface after peeling.

[0215] The fifth layer of the protective film in Comparative Example 2 contained only 2% scratch-resistant agent, 0.3% UV absorber and antioxidant, and SIS elastomer was added to the second layer, resulting in insufficient scratch resistance and aging resistance.

[0216] Table 1: Comparison of Examples 1-3 and Comparative Examples 1-2

[0217]

[0218]

[0219] Table 2: Comparison of key differences between Examples 1-3 and Comparative Examples 1-2

[0220]

[0221]

[0222] As shown in Table 1-2, Comparative Examples 1-2 had residual adhesive due to the use of SBS / SIS elastomers (poor compatibility); Examples 1-3 all had tensile strength ≥25MPa and elongation >500%, meeting the German Volkswagen QP R015 standard, while the cost was more than 30% lower than TPU film and far lower than similar products on the market; This utility model uses a polypropylene (PP) / polyethylene (PE) and hydrogenated styrene block elastomer (SEBS / SEPS) blend system to replace expensive TPU and easily aging PVC. The SEBS / SEPS addition ratio is controlled at 20%~50%, taking into account both softness and mechanical strength. It is an innovation in materials and achieves a balance between low cost and high performance.

[0223] As shown in Tables 1-2, Examples 1-3 demonstrate that after 1200-1500 hours of UVA-340 aging testing (corresponding to 7-8 years outdoors), the change rate of fracture strength is <10%, which is superior to Comparative Examples 1-2 (without the addition of anti-aging additives, performance decreased by more than 50% after 600 hours). This invention achieves a breakthrough in improving aging resistance by synergistically adding UV absorbers, hindered amine light stabilizers, and antioxidants to the base layer, colored layer, and scratch-resistant layer, controlling the total dosage to 0.5%-2%, and utilizing the UV blocking effect of titanium dioxide in the white masterbatch. This results in a lifespan exceeding 5 years.

[0224] As shown in Table 1-2, Examples 1-3 passed the "five-finger scratch test" with a resistance of 15N; Comparative Examples 1-2, due to the absence of scratch-resistant agent or insufficient dosage (≤2%), showed permanent scratches after only 5-8N. This invention optimizes scratch resistance and self-healing functions by adding 5%-10% of a highly transparent scratch-resistant agent (such as SR100B or KM-1) to the scratch-resistant layer and improving surface smoothness through casting molding.

[0225] This invention employs a solvent-free multilayer co-extrusion casting process, avoiding the toxic volatiles of traditional solvent-based adhesives. By controlling the cooling temperature and film thickness, it ensures the protective film remains undeformed, achieving both environmental friendliness and improved process stability. By using white or low-saturation masterbatch in the base color layer, combined with high-saturation masterbatch in the color layer, and integrating a highly transparent scratch-resistant layer, it achieves a balance between color vibrancy and gloss. Through material system optimization (SEBS / SEPS blending), synergistic use of aging-resistant and scratch-resistant additives, innovative venting design, and environmentally friendly processes, it solves the pain points of existing color-changing films, namely "high price, short lifespan, and difficult construction," achieving a comprehensive advantage of "low cost (comparable to PVC), long lifespan (≥5 years), and high performance (scratch-resistant, residue-free)."

[0226] The foregoing descriptions and embodiments are provided to enable those skilled in the art to understand and apply this utility model patent. Those skilled in the art will readily make various modifications to these contents and apply the general principles described herein to other embodiments without inventive effort. This utility model patent is not limited to the foregoing descriptions and embodiments. Any improvements and modifications made by those skilled in the art based on the disclosure of this utility model patent without departing from its scope should be within the protection scope of this utility model patent.

Claims

1. A self-adhesive polyolefin automotive paint surface refinish protection film, characterized in that, This includes a multi-layered structure arranged sequentially from the inside out, wherein the multi-layered structure includes at least four core functional layers, which are, from the inside out: Adhesive layer, used for bonding to the car paint surface; The base color layer is located outside the adhesive layer; The colored layer is located outside the base color layer; A scratch-resistant layer is located outside the colored layer; The four core functional layers are integrally formed by co-extrusion process, with each layer arranged sequentially along the thickness direction and composite without gaps.

2. The self-adhesive polyolefin automotive paint resurfacing film of claim 1, wherein, The multilayer structure also includes a protective PET film layer, which is located outside the scratch-resistant layer and is bonded to the scratch-resistant layer.

3. The self-adhesive polyolefin automotive paint resurfacing film of claim 1, wherein, The multilayer structure also includes a textured release film layer, which is located inside the adhesive layer, and the surface of the textured release film layer is provided with a textured surface.

4. The self-adhesive polyolefin automotive paint resurfacing film of claim 3, wherein, The textured release film is made of PET material, and the mesh count of the textured surface is 500-2000 mesh.

5. The self-adhesive polyolefin automotive paint resurfacing film of claim 1, wherein, The adhesive layer has a thickness of 20–30 μm, and inorganic microspheres with a particle size of 5–30 μm are distributed within the adhesive layer.

6. The self-adhesive polyolefin automotive paint color-changing protective film according to claim 1, characterized in that, The total thickness of the four core functional layers is 80–130 μm, of which: The thickness of the adhesive layer is 20–30 μm; The thickness of the base color layer is 20–35 μm; The thickness of the colored layer is 20–35 μm; The thickness of the scratch-resistant layer is 20–30 μm.

7. An apparatus for manufacturing the self-adhesive polyolefin automotive paint refinish protection film according to any one of claims 1 to 6, characterized in that, include: An extrusion system comprising four extruders, the discharge ends of which are connected to the same co-extrusion die via screws; The co-extrusion die includes a multi-layer distribution channel and a four-layer co-extrusion flat die head, wherein the multi-layer distribution channel is connected to the four extruders in a one-to-one correspondence; The cooling and shaping mechanism includes a first cooling roller and a second cooling roller arranged sequentially along the protective film forming direction. The first cooling roller is a mirror roller, and the second cooling roller is an anti-sticking roller. A PET film laminating device includes at least one pressure cylinder and a pressure roller, the pressure roller being used to press a PET film onto a protective film surface; The edge trimming and winding device includes a traction roller and a take-up roller, and a tension adjustment mechanism is provided between the traction roller and the take-up roller.

8. The apparatus of claim 7, wherein, The surface of the first cooling roller is chrome-plated and polished, and the surface of the second cooling roller is coated with an anti-stick coating. The surface temperature of the first cooling roller and the second cooling roller is 10-30℃.

9. The apparatus of claim 7, wherein, The inner diameter of the pressure cylinder of the PET film composite device is 120mm, and the unit pressure of the pressure roller can be adjusted to 0.6-1MPa.

10. The apparatus of claim 7, wherein, The edge-cutting and winding device integrates a tension sensor closed-loop feedback system, which achieves dynamic tension adjustment through PLC, servo drive and PID algorithm, with a winding tension of 50-100N.

11. The apparatus of claim 7, wherein, The equipment also includes a twin-screw extruder for pre-granulation of the adhesive layer material to prevent the mixture from clogging at the hopper inlet of the single-screw extruder.

Images