Sticky/Oily substance in telephone cords.

[LM Ericsson]

I was dusting my telephone collection today and I came across one of my telephone's handset and line cords have this oily substance on them. I have never noticed this and not all my telephones have this issue. What is causing this?

[unbeldi]

I presume these  are plastic or synthetic rubber cords?  Are these original cords?
Some of these materials indeed are known to re-liquify, or components oozing out, after some time in some conditions.

For example, I have a box of Western Electric modular cords, sealed in their original plastic bags, from the 1980s or so, and most of them exhibit the same phenomenon. They are very sticky as if covered with glue. The stuff is very hard to remove even with alcohol or acetone.

Synthetic rubber often contained softeners such as oils that were added in high percentage before coagulation, providing the softness that was achieved with natural rubber.  A third of the weight of such rubbers may actually be such added plasticizing compounds.

[LM Ericsson]

Indeed yes. One of them is the cords of my Decotel Candlestick telephone.

[Matilo Telephones]

I understood that this is often the softening agents leaking out of cords of lesser quality. In the case of PVC cords that is.
It also causes stickyness of the cords and damages other plastics and painted surfaces.

Wouldn't depolymerisation of the PVC cause the cord to go brittle?

[unbeldi]

I understood that this is often the softening agents leaking out of cords of lesser quality. In the case of PVC cords that is.
It also causes stickyness of the cords and damages other plastics and painted surfaces.

Wouldn't depolymerisation of the PVC cause the cord to go brittle?

Depolymerization indeed is a break down of the structure of the plastic, so you would expect brittleness eventually. But the synthetic plastics used for cords are never really hard plastics, rather they are elastomers, just not as soft as natural rubber, and so they are softened by additives.  When the oils leak out, they become less elastic, stiffer. For them to completely dry out, would probably take a very long time.
Natural rubber actually hardens worse than synthetic kinds usually, and becomes brittle and breaks up. We all have seen that in old telephones many times.

[TelePlay]

They are very sticky as if covered with glue. The stuff is very hard to remove even with alcohol or acetone.

Have you tried something closer to the dielectric constant of the sticky stuff? Acetone is quite polar, alcohol not as much. I haven't tried it but was wondering if something like mineral oil, corn oil, etc. might disolve the stuff better and then. when clean of the sticky substance, the oil desolving oil could be simply cleaned off with dishwashing soap and water. Any thoughts?


xzzx - polar - xzzx

[unbeldi]

They are very sticky as if covered with glue. The stuff is very hard to remove even with alcohol or acetone.

Have you tried something closer to the dielectric constant of the sticky stuff? Acetone is quite polar, alcohol not as much. I haven't tried it but was wondering if something like mineral oil, corn oil, etc. might disolve the stuff better and then. when clean of the sticky substance, the oil desolving oil could be simply cleaned off with dishwashing soap and water. Any thoughts?

You may be right, but personally, I have not experimented much, acetone did a quick job of getting a lot of the stickiness off, but I ran a cord through the acetone-soaked towel just very quickly as not to damage the plastic with the solvent, which could conceivably dissolve the whole thing.  I suspect my box full of them will sit for another decade before being used up.

[Russ Kirk]

They are very sticky as if covered with glue. The stuff is very hard to remove even with alcohol or acetone.

Have you tried something closer to the dielectric constant of the sticky stuff? Acetone is quite polar, alcohol not as much. I haven't tried it but was wondering if something like mineral oil, corn oil, etc. might disolve the stuff better and then. when clean of the sticky substance, the oil desolving oil could be simply cleaned off with dishwashing soap and water. Any thoughts?

you state Acetone is quite polar.  what does that mean?

Also to all, i find this thread quite informative.  I have also noticed the stickiness of my cords on storage. it is quite annoying. I used the bell system cord cleaner in the past but ran out of my stock many years ago.  I do have a suggestion for this thread, is there anyway the title can be changed to someting with sticky cords?  That way we can find it easily in the future.

Thanks!

[Kenton K]

I regularly use degreaser or alcohol to remove the cord grime. Works great.

Kk