Precautions for PE color-coated aluminum coils in the production of aluminum-plastic panels

Precautions for PE color-coated aluminum coils in the production of aluminum-plastic panels

In the process of producing aluminum-plastic panels, PE color-coated aluminum coils are one of the key raw materials. Their quality and processing methods have an important impact on the performance and appearance of the final product. The following is a detailed analysis of the precautions for PE color-coated aluminum coils in the production of aluminum-plastic panels based on the information I searched:

1. Cleaning and pretreatment

PE color-coated aluminum coils must be strictly cleaned and pretreated before use to ensure that the surface is clean and to avoid impurities affecting the adhesion of the coating. The cleaning process usually includes spray degreasing, water washing, neutralization, chemical treatment, water washing, drying, cooling and winding steps .

Degreasing and neutralization: remove lubricants, antioxidants and dirt on the surface to form a chemical protective film to improve the antioxidant capacity and extend the life of the paint film .

Drying and cooling: After the aluminum coil is preheated to 95°C, it is pulled into the laminating process and hot-pressed and laminated using the uncooled temperature of the PE plate (50-60°C) to ensure uniform coating .

Incomplete cleaning: If the cleaning is not thorough, the coating will peel off or the adhesion will not be strong, affecting the durability of the aluminum-plastic panel.

2. Coating process

The coating of PE color-coated aluminum coil is a key step in the production of aluminum-plastic panel, which directly affects its surface quality and weather resistance. Common coating methods include roller coating and spray coating. Commonly used coatings include polyester resin (PE), polyvinylidene fluoride (PVDF), etc..

Coating thickness: Fluorocarbon coatings usually adopt a three-layer structure (primer, topcoat, and varnish), with a total thickness of 30μm. Each layer needs to be baked at above 200℃ for about 60s.

Coating uniformity: If the coating is too thin, it will cause drawing and uneven surface; if it is too thick, it will easily bubble, and it will not dry after the oven and will easily stick.

Drying control: The drying temperature and time must be strictly controlled. If the time is too long, it will easily cause the coating to burst, and if the time is too short, the drying will not be thorough.

Coating selection: Different coatings have different requirements for aluminum plates and need to be selected according to specific needs. For example, polyester resin is suitable for interior decoration, while fluorocarbon resin is suitable for harsh climate environments.

Environmental requirements: The workshop should maintain a dust-free environment to prevent dust from falling onto the paint surface, resulting in unqualified appearance.

3. Composite process

The composite of PE color-coated aluminum coil and PE core material is the core link in the production of aluminum-plastic panels, and its quality directly affects the overall performance of the product.

Composite temperature: During hot pressing composite, the heating temperature of the aluminum coil and the PE core material is controlled at 200-220℃ to ensure strong adhesion.

Composite pressure: During the hot pressing composite process, it is necessary to extrude the PE plate with a rubber roller to ensure that the polymer film is coated on both the upper and lower sides at the same time, and it is required to be wrinkle-free and bubble-free.

Composite materials: PE core materials are usually three-layer structures (adhesive/PE/adhesive), which are produced by co-extrusion or layering to ensure the close combination of the core material and the aluminum plate.

Composite quality: Factors affecting peel strength include polymer film thickness, maleic anhydride content, melting point, etc., which need to be adjusted according to process parameters .

Post-composite processing: The composite aluminum-plastic panel needs to be cooled, shaped and laminated with a protective film to ensure its flatness and stability .

4. Protective film and lamination

The protective film is an important measure to prevent the surface of the aluminum-plastic panel from being damaged during transportation and processing.

Protective film thickness: It is recommended to use a protective film with a thickness of 5-7 threads. The viscosity should not be too high to avoid subsequent removal difficulties .

Lamination process: The protective film needs to be laminated after cooling to ensure that the temperature is appropriate to avoid the film layer from falling off due to excessive temperature .

Film peeling time: The protective film should be peeled off within 45 days after the aluminum coil is installed, otherwise it will be difficult to peel off the film or the glue will be transferred .

5. Cutting and processing

The cutting and processing of the aluminum-plastic panel should be carried out according to the design specifications to ensure dimensional accuracy and edge quality.

Cutting accuracy: After cutting, the aluminum-plastic plate needs to be trimmed to ensure that the edge is smooth and avoid burrs or gaps .

Processing environment: The processing environment temperature should be above 7°C. The gap between the processing rollers should be adjusted according to the thickness of the aluminum coil, and foreign matter should be removed to ensure that the coating does not fall off .

Processing direction: When installing aluminum coils of the same color on the same plane, the flow direction should be consistent, otherwise visual color difference will occur .

6. Transportation and storage

During transportation and storage, PE color-coated aluminum coils should be protected from moisture, oxidation and damage.

Moisture-proof: Aluminum coils should be wrapped in plastic film and placed in a dry environment to avoid oxidation .

Anti-oxidation: Avoid opening the package immediately when suddenly moving from a low-temperature area to a high-temperature area to avoid oxidation .

Anti-damage: Avoid collision and extrusion during transportation to prevent scratches or cracks on the coating .

7. Quality control

During the entire production process, the quality of each link must be strictly controlled to ensure that the performance and appearance of the final product meet the standards.

Coating uniformity: If the coating is too thin, it is easy to draw; if it is too thick, it is easy to bubble. Therefore, the coating thickness needs to be strictly controlled .

Peel strength: The thickness, maleic anhydride content, melting point and other parameters of the polymer film need to be optimized to improve the peel strength .

Color difference control: There may be color differences between different batches of aluminum coils. It is necessary to add a color difference comparison procedure before sales and use .

Environmental protection requirements: VOCs emissions should be minimized during the production process, and powder coatings should be used instead of solvent-based coatings to reduce environmental pollution .

8. Special process requirements

Hot pressing and laminating: During hot pressing and laminating, it is necessary to ensure that the contact surface temperature of the aluminum coil and the PE core material is uniform to avoid local overheating or overcooling resulting in poor bonding .

Cooling system: The cooling system needs to match the increased production speed to ensure that the aluminum-plastic panel cools quickly and maintains flatness .

Pressing and molding: The aluminum-plastic panel is pressed into a concave and convex structure through pressing and molding equipment to improve structural strength and safety of use .

9. Safety and environmental protection

Safe operation: During the unwinding, laminating and cutting of aluminum coils, protective equipment must be worn to avoid mechanical injuries.

Environmental treatment: Wastewater, waste gas and waste packaging materials generated during the production process must be properly handled to reduce the impact on the environment.