断桥铝门窗的中枢纽部件是在两部份铝合金型材间起到连接作用的“隔热条”，隔热条的这种使用性质决定了其必需同时具备较高的力学性能，否则在长期使用过程中因为其自身的老化易造成门窗、幕墙断裂脱落，存在重大质量安全隐患，所以隔热条的材质选择显得至关重要。
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.
杂质的存在会给隔热条力学性能带来一定的影响，对此部分厂家通过加入某些增强剂，可以使隔热条初期力学机能得到改善，但因为这些材料是经由多次反复加工使用，树脂基体内存在大量可致降解的自由基，经由一段时间的使用，部份树脂将发生分子链的断裂，如尼龙6相邻分子间的氢键结合比拟尼龙66弱，耐热机能相对较差，在加工成型及后期使用中都易发生降解，从而影响隔热条整体性能。
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.
断桥铝门窗具有重量轻、强度高、刚性好、耐腐无毒、防火机能优异、采光面积大、装饰效果好、使用寿命长等特点，因此广泛为社会所接受。但是，因为劣质原材料成份复杂，其在性能方面存在根本缺陷，经由一段时间的使用后，隔热条非常容易老化，力学性能下降，给产品带来很大的质量隐患和安全隐患。然而目前因为原料、生产成本大幅上涨，国内隔热条市场极为混乱，各种劣质隔热条浑水摸鱼，瞒天过海，原材料档次也相差甚远，有正牌料、水口料和回收垃圾料之别，质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.
