Hygroscopy is described as an objects ability or characteristic to absorb/ give up moisture into its surrounding atmosphere. A great way to think of this is a tree. We all know that trees “suck up” co2 from the atmosphere and release oxygen back into it. Nylon plastic parts do the same with moisture based on the humidity of their environment.
Nylon has great thermal and electrical insulating properties but the problem with nylon in professional industries is that it becomes brittle and susceptible to cracking under pressure when it is too dry. Many of the automated processes dealing with manufacturing these parts requires using force on them
This poses a unique challenge to OEM manufacturers of these types of parts because very special storage is required to handle these products.
The good new is, even if a part is 25 years old, it can still be reconstituted with moisture to make them usable again.
How To Re-Moisturize Nylon Connectors – see documentation
When we think of evaporated water in our atmosphere, we do not often associate minerals with the liquid. This factor is important for re-moisturizing parts because precious metals are used in many of them, and corrosion is possible and likely if the wrong methods are used.
De-Ionized water MUST be used for this process as it has had the minerals naturally present in the water removed so that no static charge can build on the part and cause corrosion.
Step 1. – Environment
The absolute most important part of this process is the environment. Nylon’s properties make it so that if the part is more dry than its atmosphere it will absorb moisture readily until it is fully saturated.
This process take around 24 hours for most nylon objects as long as the environment’s humidity is constantly higher than the object.
At C-T Wire Prep Inc. we use heat-sealed packing style bags to humidify and store terminals and connectors for longevity.
The other more expensive option which serves companies well with many different parts being treated, a humidified storage room can be a better solution. although, this solution comes with a host of other issues related to mold and moisture damage to structures.
Step 2. – Sponge
The easiest way to hold moisture for a period of time in the enclosed environment is to use a sponge sealed inside the bag with a metered dosage of de-ionized water.
linked HERE is a document directly from Molex International describing the process.
Although there are specifications on how much water is to be used (25ml per 1kg parts), you must account for other hygroscopic components inside the atmosphere as well. Any cardboard reels and paper separation tape will also absorb the moisture readily and so must be offset to achieve the desired moisture in the parts.
In conclusion, there is hope for your parts! We have had some success with re-constituting very old parts, but it sometimes requires up to 1 week with multiple treatments.