Aluminum composite panel is a new type of material made of surface-treated and coated aluminum as the surface and polyethylene and polypropylene plastic mixed as the core layer, which is compounded by a series of processes. Since aluminum composite panel is composed of two materials (metal and non-metal) with different properties, it retains the main characteristics of the original composition materials (metal aluminum, non-metal polyethylene plastic) and overcomes the shortcomings of the original composition materials, thus obtaining many excellent material properties, such as luxury, colorful decoration, weather resistance, corrosion resistance, impact resistance, fire prevention, moisture resistance, sound insulation, heat insulation, shock resistance; light weight, easy processing and molding, easy handling and installation. These characteristics have opened up a broad application prospect for aluminum composite panels. The production of aluminum composite panel seems to be very simple to the layman, but in fact it is a new product with high technical content, so there is a certain technical difficulty in the quality control of aluminum composite panel products.
The following mainly discusses the factors affecting the 180° peel strength of aluminum composite panels.
1. The quality of the aluminum foil itself：
It’s a relatively hidden problem, but has been reflected in the quality of aluminum composite panels. On the one hand, there is the problem of heat treatment process of aluminum, on the other hand, there are aluminum sheets and producers who are not strict in quality control when using recycled aluminum scrap. This requires producers of aluminum composite panels to establish business transactions to ensure material quality after evaluating all aspects of the material producers and identifying qualified subcontractors.
2. Pre-treatment problems of aluminum sheet：
The quality of cleaning and chemical layer of aluminum plate is directly related to the composite quality of aluminum-plastic plate. Aluminum plate should first be cleaned to remove surface oil and impurities, etc., so that the surface forms a dense chemical layer, in order to produce a good bonding polymer film. But some manufacturers in the pre-treatment process on the temperature of the treatment fluid, concentration, processing time, treatment fluid updates, etc. control is not strict, affecting the quality of cleaning.
What's more, individual new manufacturers do not carry out any pre-treatment of aluminum plate and directly use. All these will certainly lead to poor composite quality, 180 ° peel strength is low or unstable.
3. Core material selection issues：
Because the polymer film and PE bonding with other plastics compared to the best effect and moderate price, non-toxic, easy to process. Some small manufacturers choose PVC with poor bonding effect and deadly poisonous gas when burning in order to reduce cost, or use PE recycled material or PE raw material mixed with off-cuts. This will lead to different compounding temperature because of the different types of PE, aging degree, etc., and the final surface is unstable compounding quality.
4. Problems of polymer membrane selection：
Polymer film is a kind of bonding material with special properties, which affects the main factor of compound quality. The polymer film is two-sided, with three co-extruded layers. One side is bonded with metal, the other side is bonded with PE, and the middle layer is PE substrate, the nature of the two sides is completely different. The price difference between the two sides of the material is huge. The material for bonding with aluminum plate needs to be imported and is expensive.
Therefore, some polymer film manufacturers make a big deal about it and use a lot of PE fusion material to cut corners and make huge profits. The use of polymer film is directional and the positive and negative sides cannot be swapped. Polymer film is a kind of self-dissolving film, incomplete fusion will lead to false composite. Early strength is high, a long time, due to the influence of weathering will reduce the strength, and even bulging or open glue and other phenomena.