In the construction of buildings, the climate zone, the orientation of the façade and the width of the windows are some of the variables that determine the characteristics of the construction materials for door and window frames.
The higher and higher thermal insulation performance required by the market of steel structures makes the thermal bridge rupture increasingly widespread in aluminium profiles.
The thermal bridge rupture is obtained through a polyamide profile mechanically placed between two aluminium profiles of the window frame. Normally, this polyamide profile is incorporated before the coating stage: in these cases, it undergoes the same treatment and coating processes of the aluminium profiles, which causes a bad finish in the area of the polyamide. Although the types of defects may be different, the poor finish is typically due to the presence of some bubbles, also called "blistering", as can be seen in fig. 1. The size of the bubbles is in direct relation to the degree of moisture in the polyamide. Several laboratory studies have shown that the water present in the polyamide, because of the evaporation due to the heat of polymerisation, stretches or lifts the organic coating in the melting stage and thus remains trapped, forming the bubbles of the blistering effect.
Adapta has developed a new line of powder coatings called ADAPTA NBP (Non-Blistering Polyamide), which minimises this defect by allowing the moisture present in the polyamide to be released. In this way, a uniform finish is obtained, especially with the textured finishes, which are usually the most critical ones. The product can be customised on request in terms of colour, and can be developed in a standard or a super-durable polyester.
This innovation takes place simultaneously with the launch of the new "NEON Collection", including a wide range of fluorescent colours.
For further information: www.adaptacolor.com
Picture: On the left, the blistering effect that can be observed on a normal coating. On the right, the demonstration of how with the new powder coatings from the ADAPTA NBP range, the blistering effect is minimised because the moisture content of the polyamide is released, thus ensuring a uniform finish.