2015-10-06 / News

Coex sealing wire: who invented it?

The coex sealing wire in the insulating profile is used to create a perfect seal of the assembled system, and as well as ensuring a reliable moisture barrier, also brings about an additional safeguard against displacement of the assembly. Most insulbar® insulating profiles as well as other insulating bars are supplied with coex wire nowadays as a standard feature at no additional cost.

What many people don't know: This coextruded sealing wire was actually originally developed at Ensinger. At the beginning of the nineteen nineties, a patent for the product was granted to the plastics specialist. This put an end finally to the laborious manual closure of profile ends prior to powder coating which had been customary in the past. The mono sealing wire frequently used at the time was actually made of a pure hot-melt glue which was unable to withstand the powder coating process without melting. If an additional plugging work stage was not carried out, it would drip out of the profile ends.

Then as now, the special feature of coex sealing wire is the carefully coordinated interaction between the material of the core and sheath. The pre-stretched polyamide core is sheathed in hot-melt glue. What is known as the memory effect of the PA66 causes the wire core to contract, taking with it the hot-melt glue at the wire ends and so preventing the glue from dripping out at the ends of the profile. As the glue sheath melts while the coating is being baked, the capillary joint between the insulating bar and the aluminium profile is filled and a splash-proof seal is created.

Since the Ensinger patent expired, other manufacturers quickly climbed onto the bandwagon, and today all customary insulating profiles are fitted with coextruded sealing wire.