The advantages and disadvantages of sealing strip performance affect the important performance indexes of doors and windows such as air tightness, waterproof and heat loss of building doors and windows and the firmness of doors and windows to a great extent. Therefore, the state has formulated the national standard GB12002-89 "plastic door and window sealing" for a long time to standardize the production and inspection of sealing.
However, the current quality and price of rubber and plastic sealing strips for doors and windows in the building materials market are very chaotic. The price is 156000 yuan a ton, and the price is only 6000 yuan a ton. The price difference is nearly 10000 yuan, and the quality varies greatly. We all know what to do. Many manufacturers say that their seals are in accordance with the national standard GB12002-89, and qualified test reports can be issued by authorized institutions. According to the rubber seals of well-known manufacturers currently used in the industry and the sealing strip samples sent by the manufacturers, the effect of hot air aging performance of the project in the heating weight loss index is surprising: no one is qualified for more than 10 samples.
According to the provisions of GB12002-89 standard, the hot air aging performance of sealing strip shall be 3% in the heating weight loss index. The heating weight loss of the actual test results is 7.17% ~ 22.54%, which is far beyond the scope of the national standard.
For such a sealing strip, a large amount of low boiling point plasticizer or plasticizer substitute is added to the formula. This seal in the new era, flexibility, flexibility is still very good. However, with the passage of time, the plasticizer has greater volatility, good sealing elasticity and softening deterioration, which not only affects the sealing performance from the impact force of doors and windows, but also affects the firmness of door and window assembly.
In addition, the plasticizer content of the sealant is too high, and it is in contact with the migration phenomenon of PVC resin during the use of plasticizer. Causes shadows and swelling of the local fan frame. In other words: in contact with the seal on the sealing surface, there is a wide and narrow, non wiping, black stain and white body, forming a strong contrast, which greatly affects the appearance. The color of the plasticizer is due to migration and local uplift. (since the sliding doors and windows are not exposed in contact with the profile of the parts, the local coloring and expansion of the profile can not be observed in general. The open doors and windows are in the open state, and the expansion phenomenon has been exhausted since the contact between the seal and the corresponding profile.) although the local coloring and expansion profile will not cause serious consequences for the failure of the frame and fan profile, But it has seriously affected the appearance of plastic doors and windows. After all, this is a defect. After all, the image effect of plastic doors and windows is very poor.
In order to maintain the image of plastic doors and windows and care about the healthy and strong growth of this emerging industry, seal manufacturers should actually produce a truly qualified seal, and plastic door and window assembly plants should use truly qualified high-quality seals.