Some unscrupulous merchants use PVC plastic or low-end nylon (such as PA6) to (pass off as) PA66 to reduce costs. The thermal expansion coefficient of PVC plastic is about 5×10⁻⁵/℃, which is far from that of aluminum alloy. During long-term use, due to the imbalance of thermal expansion and contraction, it is easy to cause door and window deformation, air and water leakage, and the thermal insulation effect is greatly reduced. However, high-quality brands like Kaimingde strictly select raw PA66 nylon materials and conduct precise laboratory testing to ensure that every thermal insulation strip has the characteristics of high strength, high toughness, and low thermal conductivity, eliminating the hidden danger of "fake thermal insulation" from the source.
High-quality thermal insulation strips are not only carefully selected in terms of materials but also have unique ingenuity in design. Adopting a multi-cavity structure design, the width of the thermal insulation strip is more than 24mm (ordinary doors and windows are only 14-18mm), forming a wider heat barrier zone and significantly reducing heat conduction between indoor and outdoor. Combined with the unique "double broken bridge" technology, sealing strips are added on both sides of the thermal insulation strip to form a double barrier of "thermal insulation + sealing". According to professional tests, the overall heat transfer coefficient (K value) of doors and windows can be as low as 1.8W/(㎡·K), and the thermal insulation effect is improved by more than 30%.
In addition, the dimensional accuracy of thermal insulation strips is also crucial. Zhimei thermal insulation strips, relying on years of technical precipitation, advanced equipment, and processing technology, produce thermal insulation strips with a deviation of less than 0.05mm, ensuring the precision and consistency of each product. Thermal insulation strips from different batches can be properly (threaded and compounded) on profiles of the same specification, effectively guaranteeing the overall performance of broken bridge aluminum doors and windows.