Crosslinking Cables - FAQ

Following the sale of the polyolefin cross-linkable compounds business, starting June 1st 2017 all requests for Cogegum® XLPO-HFFR, Polidan® PEX/XLPE and Polidiemme® XLPO have to be sent to the following e-mail address:

Frequently Asked Questions

How much do general properties depend on the crosslinking rate?

In general, mechanical and physical properties don’t depend so much on the crosslinking rate. In some cases, a small decrease in E.B. and increase of tensile modulus can be observed, but differences are not so evident to be quantitatively related to the crosslinking rate

How can we implement a fast method to check the potential crosslinking of the material?

The fastest method is to put a cable sample in hot water at 90-95°C (194-203°F) for 1-2 hs (Polidan® and Polidiemme® G grades) or 4-6 hs (Cogegum® GFR grades); remove completely the water from the specimens and then apply the procedure to determine the crosslinking rate.

How can crosslinking of cable be accelerated?

Crosslinking time of cable can be accelerated by storing the reels in a conditioned chamber where an ambient temperature of 40-50°C (104-122°F) and r.h. around 70-80% is achieved by mean a small steam generator; depending on cable construction and material, crosslinking time may require from 12 to 48 hs to achieve a satisfactory crosslinking rate

Should we expect that the inner coils of the reel crosslink slowly than the outer coils?

No, it has been experienced that normally the inner coils crosslinking speed is the same as the outer coils

Is it necessary to wait for the complete crosslinking before continuing with cable construction?

No, it’s not necessary to wait for the complete crosslinking; after the crosslinking process starts, then the construction of the cable can proceed without affecting the crosslinking or other properties

Are there some extrusion conditions that can improve crosslinking speed?

Setting the water temperature in the cable cooling basin at 50-60°C (122-140°F) and leaving a small amount of water on cable (not dry completely the cable before collecting on the reel) may help to keep moisture level and temperature on cable higher and make crosslinking faster.

Can we increase the Catalyst MB dosage to make crosslinking faster?

Yes, but also the reactivity of the system increase, and extrusion process could be more under risk of pre-crosslinking in the extruder; in case, it is suggested to overdose not more than 30% respect the nominal dosage.