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What To Do if PET Straps Get Brittle

PET strap , currently is one of the new types of environmental friendly packaging materials instead of steel straps for strapping tool. In the past few years and the successful development of new materials costs dropped significantly, PET has become a new type of high-strength steel replacement strap.


As most PET producers know , if recycled materials adopted for processing, producing straps would be very brittle , and the rejection rate is quite high. Most supplier may also b worried about how to solve these problems, NUODA will reveal the analysis for  causes and solutions.


In the production of PET material straps with recycled materials , equipment status as follows: Sec. 3 -5 segment single screw machines , drying temperature about 180 ℃ , bake for 6-8 hours , the processing temperature 250 ℃ - 260 ℃. Under this situation, PET is very brittle , the rejection rate is also high, how to solve this problem ?


Analysis : PET plastic is sensitive to water , heating and drying time to degradation of the material itself , a single screw extruder generates frictional heat is easily degraded , so during machining process, should adjust the temperature according to the actual condition. The material is very brittle because the production process of molecular chain get scission ( degradation ) serious , molecular weight is low , viscosity is not enough. Which result PET strap brittle , the rejection rate is too high.


Solution: shorten the drying time by 4-6 hours , adopt the chain extender ( BASF JONCRYL), for preventing degradation , increasing the molecular weight chain extender to enhance intrinsic viscosity . This would decrease the phenomenon of viscosity and brittleness after processing.