Analysis of the causes of aluminum composite panel peeling.
Aluminum-plastic sheet is a new material made of surface treated and coated baked aluminum sheet as the surface, polyethylene, polypropylene plastic mixed as the core layer, after a series of process composite. Because the aluminum-plastic sheet is composed of two materials (metal and non-metal) with very different properties, it retains the main characteristics of the original composition materials (metal aluminum, non-metal polyethylene plastic), but also overcomes the shortcomings of the original composition materials, and thus obtains many excellent material properties, such as luxury, colorful decorative, weather resistance, corrosion resistance, resistance to impact, fire prevention, moisture resistance, sound insulation, heat insulation, shock resistance; light weight, easy processing and molding, easy handling and installation, etc. 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 panel.
1. Quality of the aluminum foil itself.
This is a relatively hidden problem, but it has been reflected in the quality of the aluminum foil. On the one hand, there is the problem of heat treatment process of aluminum, on the other hand, some aluminum sheets and producers are not strict in quality control when using recycled aluminum scrap. This requires the producers of aluminum composite panels to establish business transactions to ensure the quality of materials after evaluating all aspects of the material producers and determining qualified subcontractors.
2. Pre-treatment problem of aluminum plate.
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 impurities, etc., so that the surface to form a layer of 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 pretreatment of aluminum plate and use it directly. All these will certainly lead to poor composite quality, 180 ° peel strength is low or unstable.
3. The choice of core materials.
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 toxic gas when burning in order to reduce cost, or use PE recycled materials or PE raw materials 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 for the composite quality is not stable.
4. polymer film selection issues.
Polymer film is a bonding material with special properties, which affects the main factors of composite quality. Polymer film has a two-sided, three-layer co-extrusion. One side is bonded with metal, the other side is bonded with PE, the middle layer is PE substrate, the nature of the two sides are 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.
Analysis of common quality problems in aluminum curtain wall projects.
1. Discoloration and decoloration of aluminum composite panel.
The discoloration and decoloration of aluminum composite panels are mainly caused by the improper selection of panels. Aluminum composite panels are divided into indoor panels and outdoor panels, and the surface coating of the two types of panels is different, which determines their application to different occasions. The surface of the panels used indoors is generally sprayed with resin coating, which cannot adapt to the harsh natural environment outdoors, and if used outdoors, it will naturally accelerate the aging process and cause the phenomenon of discoloration and decolorization. Outdoor aluminum composite panel surface coating is generally selected to anti-aging, anti-UV ability of fluorocarbon resin coating, the price of this plate is expensive. Some construction units cheat the owner, with the indoor plate posing as anti-aging, anti-corrosion quality fluorocarbon plate, to squeeze unreasonable profits, thus causing serious discoloration and decolorization of the aluminum plate used in the project.
2. Aluminum plastic plate open glue, shedding.
Aluminum plastic plate open glue, shedding, mainly due to improper selection of adhesives. As the ideal adhesive for outdoor aluminum composite panel project, silicone adhesive has unique and superior conditions. Previously, China's silicone adhesive mainly depends on imports, the price of many people deterred, only those high-rise buildings on the expensive curtain wall project to dare to ask for. Now, China's Zhengzhou, Guangdong, Hangzhou and other places have put into production different brands of silicone rubber, resulting in a big drop in prices. Now, in the purchase of aluminum composite panels, the salesman will recommend the kind of special fast-drying adhesive. This kind of glue can be used indoors, in the climate change of the outdoor, it will appear plate open glue, deglue phenomenon.
3. deformation of the surface of aluminum composite panel, drum.
The reasons for the deformation and drumming of the surface of aluminum composite panel are many. Previously in the construction, this kind of quality problems, we had thought that the quality of the plate itself; later, after we focus on the analysis only to find that the main problem in the paste aluminum composite plate on the grass-roots plate, followed by the quality of the aluminum composite plate itself. Dealers often provide us with the construction process of aluminum composite panel, the recommended base material is mainly high density board, woodworking board and so on. In fact, this kind of material in outdoor use, its service life is very fragile, after the wind, sun, rain, will certainly produce deformation. Since the grass-roots materials are deformed, then as the surface layer of aluminum composite panel that there is no reason to deformation? It can be seen that the ideal outdoor base material should be after rust-proof treatment angle steel, square steel pipe knotted into the skeleton is better. If conditions allow, the use of aluminum profiles as a skeleton is more ideal.
This kind of metal materials made of skeleton, its cost is not much higher than the wood keel, high density board, can really ensure the quality of the project.
4. Aluminum plastic plate glue seam neatly.
When aluminum composite panel is decorated on the surface of the building, there is generally a gap of certain width between the panels. For the sake of aesthetic needs, generally have to fill in the gap with black sealant. In order to save time, some constructors do not use paper tape to ensure the neatness and rules of gluing, but use the protective film on the surface of aluminum composite panel as a substitute. As the aluminum composite panel is cut, the protective film will produce different degrees of tearing situation, so use it as a substitute for the protective tape, it is impossible to clean up the glue seam neatly.