斷橋鋁門窗的中樞紐部件是在兩部份鋁合金型材間起到連接作用的“隔熱條”，隔熱條的這種使用性質決定了其必需同時具備較高的力學性能，否則在長期使用過程中因為其自身的老化易造成門窗、幕墻斷裂脫落，存在重大質量安全隱患，所以隔熱條的材質選擇顯得至關重要。

　　The core part in insulating window is the two thermal insulating bars that connect two parts of the aluminum frame. The usage of insulating bar has required that it shall possess high mechanical performance; otherwise, its aging may result in falling off of window, door or curtain wall after long tern service, bringing remarkable quality and safety risks. Therefore, the selection of insulating bar is extremely important.

　　雜質的存在會給隔熱條力學性能帶來一定的影響，對此部分廠家通過加入某些增強劑，可以使隔熱條初期力學機能得到改善，但因為這些材料是經由多次反復加工使用，樹脂基體內存在大量可致降解的自由基，經由一段時間的使用，部份樹脂將發生分子鏈的斷裂，如尼龍6相鄰分子間的氫鍵結合比擬尼龍66弱，耐熱機能相對較差，在加工成型及后期使用中都易發生降解，從而影響隔熱條整體性能。

　　The impurities inside insulating bars will bring negative influence to its mechanic performance. Some manufacturers add some reinforcing agent to the insulating bar material to improve its initial mechanic performance. However, since this kind of material has been processed and used for many times, there are a large among of degradable free radicals inside resin. After using for a while, some resin may encounter molecular chain fracture. For example, the combination between hydrogen bonds of neighboring nylon 6 modules is much weaker than that of nylon 66; as result, its thermal-resistance is relatively poor. After being produced into finished products, they may degrade easily and affect the overall thermal insulating performance.

　　斷橋鋁門窗具有重量輕、強度高、剛性好、耐腐無毒、防火機能優異、采光面積大、裝飾效果好、使用壽命長等特點，因此廣泛為社會所接受。但是，因為劣質原材料成份復雜，其在性能方面存在根本缺陷，經由一段時間的使用后，隔熱條非常容易老化，力學性能下降，給產品帶來很大的質量隱患和安全隱患。然而目前因為原料、生產成本大幅上漲，國內隔熱條市場極為混亂，各種劣質隔熱條渾水摸魚，瞞天過海，原材料檔次也相差甚遠，有正牌料、水口料和回收垃圾料之別，質量和性能都相差很大。

　　Since the thermal insulating aluminum window and door have the advantages of light weight, high strength, excellent rigidity, good corruption-resistance, non-hazardous, brilliant flame-resistance, large day lighting area, effective decoration and long service life, they are widely accepted by the society. However, due to application of unqualified material, the product may suffer poor mechanic performance and easy aging after using for a while, resulting in significant quality issues and safety issues. Meanwhile, rapid increase in raw material price drives rapid growth of product cost. Nowadays, the insulating bar market in China is complicated, as a lot of manufacturers adopt unqualified materials. Finally, the difference in quality and performance among branded material, drainage opening material and recycled material is significant.