1、 Accuracy of external dimensions of insulation strips
The inaccurate accuracy of the external dimensions of the insulation strip not only affects the quality of the profile composite, but also easily leads to the deviation of the external dimensions and the generation of internal stress of the composite insulation profile. This will directly affect the "three properties" (water tightness, air tightness, and wind pressure resistance) of the insulation doors and windows. To obtain accurate dimensions in nylon extrusion, high-precision molds and high-quality nylon materials with stabilizers must be available.
2、 Glass fiber structure inside the insulation strip
The internal structural quality of the insulation strip is a principle guarantee for the strength and stability of the profile.
1. Reasons for choosing glass fiber reinforcement
Due to the creep properties of nylon 66. The phenomenon where the deformation increases with time under a certain external stress. In order to suppress the creep of nylon 66, experiments have shown that nylon 66 reinforced with glass fibers is equivalent to aluminum alloy in terms of strength, rigidity, and thermal deformation temperature. It avoids the risk that the insulation strip will fall off from the profile due to the thermal expansion.
Currently, multiple manufacturers on the market are selling nylon 66 insulation strips. After testing, it has been found that some are completely filled with cheap minerals (such as calcium carbonate, talc powder, etc.), while others are reinforced by mixing most of the minerals with a small amount of glass fiber (less than 10wt%) for filling; Even nylon 66 needs to be filled with non engineering plastics such as polypropylene, polyvinyl acetate, etc!
2. Glass fiber arrangement
The horizontal and vertical arrangement of fiberglass in the insulation strip can improve both the longitudinal and transverse tensile strength. But to achieve horizontal and vertical arrangement of fiberglass, it is necessary to have suitable molds, propulsion screws, and specialized hexagonal fixtures, which are currently only mastered by Germany.
