Development And Experimental Study Of Velcro Materials

Velcro, also known as"Magic fastener"or"the hook-loop fastener". Was invented in 1948 by Swiss engineer, George de Mestral. He noticed that his dog's coat and his clothes were covered with cockleburs, his inventor's curiosity led him to study the burrs under a microscope and he noted hundreds of"hooks"on the burrs of burdock. It consists of two layers:a"hook"side, which is a piece of fabric covered with tiny hooks, and a"loop"side,which is covered with even smaller and"hairier"loops. When the two sides are pressed together, the hooks catch in the loops and hold the pieces together. This is Velcro. Velcro experienced from woven molding to injection molding in more than half century and development of Velcro entered a rapidly developing era. Zippers, buttons have been gradually replaced by Velcro and more and more widely used in our actual life. Howerer, the development of common Velcro is still relatively backward, due to its great requirement, varions classification and high cost. According to this, we designed a once-forming scheme to prepare the Velcro using a three-roller calendar to make the molten sheet form the hook shape after extruding from single screw extrusion. But common PA6 can't meet the demands of this forming method. We have to derive a modified PA6 to accomplish this forming by a extensive reading of relative report home and abroad.In this paper, the effect of different compatibilizer content on PA6/PP blending and the effect of Sericite and plasticizer on PA6 were studied. PA6/PP composites were prepared by twin-screw extruder. Compatibility, MFR, rheologic behavior, mechanical properties, microstructure and DSC were studied. The conclusions are as below:(1) The study of PA6/PP-g-MAH/PP composites exhibited good compatibility. When content of PP-g-MAH was between 2 phr and 10 phr, MFR of the composites was decreased. But tensile strength,elongation at break and notched impact strength were increased.(2) Compared with PA6/PP-g-MAH/PP composites, PA6/PP-g-DBM/PP composites had better compatibility, higher MFR and elongations, lower tensile strength and notched impact strength. PP-g-DBM was not noly a good compatibilizer of two-phase interface, but also a good plasticizer of composites. (3) Compared with untreated sericites, treated sericites have a more significant improvement on the strength of the PA6 composites. Content of the sericites has a significant influence on the PA6/sericites composite. Its tensile strength reached to an optimal value with modified sericites is 5wt%.(4) Shear strength and peel strength of Velcro we prepared reached to national standards.