How does Plasti Dip become a liquid to a solid rubber from within a can?


I bought some Plasti Dip to use on my wheels and my daughter formed a very good question. How does rubber become a liquid, shoved in a can, stay in there as a liquid, and then dry as a peelable rubber material once applied to a surface? Not just Plasti Dip, but bed liner sprays and other similar products.

I haven’t found a straightforward answer through Google.

In: Chemistry

I always assumed it was always a liquid and then exposing to oxygen solidified it… good question, I’m a plastiDipper too.

If you put powdered sugar/salt in a glass of water, it will dissolve. If you spray this on a surface, it goes on as a liquid. Once it dries, it leaves a white film.

Plasti Dip is basically a 1 part synthetic resin, dissolved in 1-2 parts naptha, and 1 part gasoline. Gasoline and naptha both evaporate quickly, so it dries extra fast.

This is the MSDS, Hexane and Toulene are basically Gasoline; Naptha is camping fuel:

As for bed liners, these are now a bit more complicated. The good ones are a urethane epoxy base. Instead of drying, they cure. They have a chemical mixed in that causes a complex reaction which leads to it hardening over time.

Well, Plasti Dip is PVC-based, so it works a lot like PVC solvent cement: there’s a resin component, some plasticizers, and a volatile solvent. In its most solid form, the PVC molecules stick to each other directly, forming a network not unlike a plate of unsauced spaghetti that has been cooked and allowed to sit until the surface has dried: the strands all stick together and form a big, unified mass. Also like spaghetti, adding a lubricant like oil to let the strands slide past each other lets them behave more like a thick liquid. PVC just uses solvents that evaporate in air.

So, when it’s made, it’s plastic. Then they dissolve the plastic in a solvent to let the strands slide apart and make it a liquid. When you expose it to air, the solvent evaporates and the material re-solidifies. The reason it acts like rubber and not plastic has to do, ironically, with the plasticizers: they let the strands move past each other just a little bit, but they aren’t volatile.

Two primary methods.

One is the material reacts with something in the air to complete a chemical reaction. The substance in the air can either act as an ingredient for the reaction (it becomes part of the new material compound) or as a catalyst (it greatly speeds up the reaction without becoming part of it).

Edit: In the case of the catalyst, the material is probably setting (becoming solid) inside the container. Its just doing so at an extremely slow rate, so it remains useable for a long time.

Two is drying. The material may be stored with a solvent. The solvent evaporates out of the material and the remaining leftover becomes a solid. Good ol’ Elmer’s glue uses this method. The liquid glue has water. Once the water evaporates the glue material is left as a solid.

Just like spray-on glues and paints, the rubber is dissolved in a solvent. Inside the can, there’s nowhere for the solvent to go, so the rubber and the solvent stay in solution. But once you spray the contents of the can out into the world, the solvent can evaporate, leaving just the rubber behind.