What binder/viscous stuff is used in twist style ballpoint pens?

[NightMind]

What binder/viscous stuff is used in (cheap?) twist style ballpoint / rollerball pens to secure cap to the twisting mechanism? 

 

I have a "De Cambridge Germany" branded pen that had oil based G2 refill leak into the twist mechanism, sealing it shut. I was able to dissolve it in the alcohol so twisting mechanism now works again. However, the cap that used to seal the mechanism sitting on top of it no longer has the same grip strength. It seems that I need to apply some more of the high viscosity sticky gel (something akin to never-setting glue?) that was holding it together.

 

So, the question is, what was this stuff and where can I get it?

 

I don't think gluing it shut is a good idea, in my other twist roller with C1 refills sliding the cap held to the twist mechanism via this viscous binder seems to be the intended refilling method.