What is the problem of bulging and delamination of aluminum honeycomb panels on the curtain wall?

Views:20 Author:Site Editor Publish Time:2026-10-13 15:27:16 Orgin:Site

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Aluminum honeycomb panels bulging and peeling off after two years on the wall? The problem lies in these four obstacles:

Aluminum honeycomb panels have a light weight, high flatness, and a large surface that is not easily deformed. In recent years, they have been increasingly used in high-rise curtain walls. But there is also another situation that follows: the board has been on the wall for one or two years, and the board inexplicably bulges, with corners curled and severe delamination of the entire board. On high-altitude walls, this is no longer a visual issue, but a hidden danger of falling boards.

Bulging and delamination seem to have two problems: bulging is a "gas" problem - water vapor or volatile substances inside the panel expand due to heat, causing the panel to lift up; Degumming is a problem of "sticking" - glue and aluminum are "separated". The two can also trigger each other: bulges loosen the adhesive layer, allowing moisture to flow in after delamination, and accelerating larger bulges.

At the root, there are actually four hurdles: glue, panel treatment, composite technology, and edge sealing.

1、Glue: It should be correct, and the usage should be even more accurate

There are inherent differences in the selection of adhesive types. At present, there are three mainstream routes: polyurethane two-component adhesive is flexible and temperature resistant, but the adhesive is sensitive to moisture and problems can occur if the environmental humidity is not well controlled; Epoxy adhesive has good adhesion and moisture resistance to aluminum, but the disadvantage is that the adhesive film is brittle and the peel strength is not high after long-term wind vibration. According to industry test data, the 180 ° peel strength of epoxy adhesive film process is about 4N/mm; The continuous thermal composite process of thermoplastic film can reach about 18N/mm, which is 3-5 times that of the former. The weather resistance attenuation is also small, but the equipment investment is large and small factories do not have it. As for those who use ordinary universal glue or hot melt adhesive to impersonate structural glue, they will crack at low temperatures and soften at high temperatures, and after being installed on the wall, they will basically appear after a winter and summer.

Even if the right adhesive is used, excessive mixing errors, prolonged placement after applying adhesive before applying pressure (surface crust cannot penetrate), and premature release of pressure before curing time, will all leave weak bonding areas that appear to be adhered but are not actually firmly bonded. This type of defect cannot be detected during factory inspection, and it will appear after a temperature difference between winter and summer. In addition, there may be residual solvents or incomplete curing in the adhesive. In summer, when the surface of the board is exposed to 60 to 70 degrees Celsius, the gas expands and directly pushes out bubbles.

2、Panel treatment: The adhesive is not aluminum, it is the "surface" of aluminum

This is a process that cannot be ignored. The surface of aluminum naturally has a layer of oxide film, as well as rolling oil and handprint oil stains. If not cleaned thoroughly, the adhesive will stick to dirty things, not to the aluminum.

The standard practice is to first clean and degrease, and then perform chrome or phosphating conversion treatment to allow the adhesive and aluminum to form a stable bond. There is also a very practical experience in the industry: adding an epoxy primer on the back of the aluminum alloy panel before lamination is equivalent to placing a "transition bridge" between the aluminum and the adhesive, which can significantly improve the bonding strength between the aluminum plate and the adhesive layer, and also improve the resistance to moisture and heat aging. There is a consensus in the metal bonding industry that the same adhesive, with or without a proper primer, can have a several fold difference in bonding life in humid and hot environments. This process is worth specifying in the technical requirements for high temperature and high humidity areas in the south and coastal projects.

After processing, there is a time limit requirement: the board cannot be left for a long time. If it is left for a long time, it will oxidize and absorb moisture again, which is equivalent to white processing. So when purchasing, priority should be given to manufacturers who have pre-treatment lines, degreasing conversion base coating composite lines, which are more controllable than outsourcing the board for secondary processing.

3、Process: Cold pressed plate and hot pressed plate are not the same thing

Based on the core material and adhesive, the exterior wall panel is subjected to constant temperature hot pressing at a temperature between 140 ° C and 180 ° C for the adhesive to fully infiltrate and solidify in place (incomplete curing below 140 ° C and easy deformation of the aluminum plate above 180 ° C); The cold pressed plate at room temperature can still stick to the factory, but its adhesion and weather resistance are one level worse. After several years of temperature difference alternation, the probability of delamination is significantly higher. Honeycomb cores are stored in damp conditions with high moisture content, and during hot pressing, the water evaporates and cannot be discharged, which is also a direct source of bulging. Industry inspections have also found that most initial defects are concentrated at the corners of the honeycomb grille where there is insufficient adhesive. In the future, under repeated wind loads, small defects will expand into large-scale delamination.

4、 Edge banding: boards with water ingress, without longevity

The four sides of the board are the only exposed positions of the honeycomb core. Without sealing the edges, rainwater flows into the core grid, causing corrosion of the aluminum core and hydrolysis of the adhesive layer. In winter, freezing can also widen the gaps, leading to failure spreading from the edges to the center. By the time the edges are visible to the naked eye, there is often already a circle of decay inside. The edges and corners generated by on-site cutting and bending must also be repaired with edge sealing. Coastal projects have salt spray erosion, and higher requirements for board configuration and edge sealing maintenance.

Cost accounting: savings in the open, losses in the dark

Reference for the South and East China markets from 2025 to 2026: Hot pressed all aluminum honeycomb panels with 20-25mm thick and 1.5mm fluorocarbon roller coated panels for exterior walls, with a comprehensive price of about 350-600 yuan/m. Common practices for low-priced panels include replacing paper cores or recycled cores, negative tolerance for panel thickness, cold pressing instead of hot pressing, and cutting off edge seals - the appearance and authenticity are almost indistinguishable.

Once the exterior wall panels are bulging and debonding in bulk, the comprehensive cost of rework usually reaches 1.5-2 times the cost of new panels, including the dismantling of hanging baskets, high-altitude dismantling, and re supply and installation stacking, and does not include project delays and breach of contract compensation.

Three things that the construction party can do

1） Specific technical requirements: hot pressing process, panel epoxy primer, four side edge sealing, aluminum core material, panel measured thickness, do not just write the four words "aluminum honeycomb board";

2）Price vigilance: For exterior wall panels that are significantly lower than the market price, first inquire about the adhesive type, core material, and process, rather than negotiating discounts first;

3）Site inspection: Cut open the middle of the board to check the core material, measure the thickness of the panel with a caliper, and tear off the cut material by hand - if the genuine product breaks, the honeycomb core and adhesive layer will not peel off; At the same time, request the peel strength test report and verify the configuration according to JG/T334-2012 "Aluminum Honeycomb Composite Panel for Building Exterior Walls".

Drum debonding is not a problem with materials like aluminum honeycomb panels, but rather a process that is skipped. Guarding the Four Passes, it remains one of the most mature lightweight slab solutions for high-rise curtain walls.