1. Plastic Thermal Strips.
The earliest thermal strips were made of plastic. Plastic thermal strip is the most commonly used in the market before PA66 nylon thermal strip.
Plastic strips are cheap, so they have a large market. But its thermal insulation contribution is very little, it can seriously affect the quality of the whole door and window even. Plastic strips can not play the role of energy saving and environmental protection. In 2017, it was published as a class 3 carcinogenic substance by the World Health Organization. So THE COUNTRY IS FORBIDDEN TO USE PLASTIC THERMAL STRIPS IN WINDOWS & DOORS. But the product with low prices are very difficult to ensure.
2. Nylon material (PA 66, PA 6)
Nylon is an engineering plastic. Its heat resistance, strength is much higher than PVC. It usually used in heat and wear resistant places. Nylon products are mainly PA66 and PA6, and PA6 also known as nylon.
PA66(polyamide 66 or nylon 66), compared with PA6, PA66 is more widely used in the automotive industry, instrument shells and other products requiring impact resistance and high strength. Polyamide resin, short for PA, commonly known as Nylon (Nylon). It is a general term for polymers containing amide groups in the backbone repeating units of macromolecules. Among the five engineering plastics, it has the largest output, the largest variety and the widest use. The main varieties of nylon are nylon 6 and nylon 66, which are absolutely dominant. Nylon 6 is polycaprolactam, while nylon 66 is polyhexanediamine adipate. Nylon 66 is 12% harder than nylon 6. Nylon 6 has a melting point of 220 degrees Celsius while nylon 66 has a melting point of 260 degrees Celsius.
Distinction of heat thermal strips
Thermal strip plays a crucial role in the quality of aluminum windows/doors. Good aluminum Windows are using PA66 thermal strips. And INFERIOR aluminum window uses PVC thermal strips. So what's the difference between these two kinds of thermal strips?
1, look at the surface gloss of the strip. The surface of PA66 nylon strip is a kind of frosted texture, the color is black. But the PVC strip looks smooth and white. A side-by-side comparison of the two is clear.
2, Nylon strip PA66 is not burning. But when you light the PVC strip, it burns and you see a little flame, and it smells like plastic. As long as we carefully observe will be able to distinguish between PA66 and PVC strips.
Simple test method of thermal strips:
1, Determine the composition by combustion.
From the fire to extinguish and have a reactive odor is PVC. The ones that smell of burning protein after burning out are PA nylon.
2, The second step visual inspection: observe the surface.
Unqualified insulation strip: surface floating fiber, not smooth;
Qualified heat insulation strip: bright surface, uniform color, no white spot.
3, The third step measurement: measurement size.
The shape dimension accuracy of the heat insulation strip not only affects the quality of the profile composite, but also has an essential impact on the water tightness, air tightness and wind pressure resistance of the heat insulation doors and Windows;
Qualified heat insulation strip size correct, beautiful appearance. Unqualified heat insulation strip outline size is not correct.
4, The fourth step weighing: measurement density.
The internal structure of high quality heat insulation strip is dense, the density is 1.30±0.05. Under normal conditions, we can simply determine the insulation density by weighing the insulation per meter. In the case of Type I 14.8, a good insulation strip weighs around 45g per meter.
5, The fifth step: determine the internal structure of the section.
The internal structure quality of heat insulation bar is the principle guarantee for the strength and stability of heat insulation profile.
Unqualified broken bridge aluminum heat insulation strip: loose internal structure, little glass fiber content, even no glass fiber, and contains a large number of pores, seriously affect the strength of heat insulation strip;
6, The sixth step transverse stretching: test strength.
Generally speaking, each big profile factory has this kind of simple machine, fixture to carry on this test. Sampling 35mm, according to the "Aluminum alloy building profiles for Auxiliary materials - Polyamide heat insulation strip" in the national standard Appendix A process operation. The transverse tensile characteristic value of high quality broken bridge aluminum insulation strip is ≥70MPa.