dyeing pvc

[mantid51]

Weird science. Can't find anything on this. I use pvc pipe to make little field aquariums for teachers/kids . Would like to dye the pipe different colors. Dye needs to be stable, non-water-soluble and non-toxic when dried or set. Anyone got some ideas? Organic solvent-soluble anilines? Other?? I know pvc cleaner stains the heck out of it, must be something else.

mantid

[Len2]

mantid,

There are many dyes for PVC. Most are added or mixed in before melting or added at the melt stage, and then pelletized or made into a final product. But, even so, they are used mainly in rigid PVC, they have terrible lightfastness, and they tend to migrate. All in all a poor choice for the application and even worse for flexible PVC.

That being said, for your application, I suppost you could dissolve an AZO or Anthraquinone in a suitable solvent, then stain the "outside" of your aquarium tube.

It would be tricky. Sol Blue 35, Sol Yellow 16, Sol Red 135, might work. I just would not recommend this as a feasible method for coloring clear PVC pipe.

Len

[Dr. Dick]

What ever you do yourself, get the MSDS (Material Safety Data Sheets) for the dye(s) you use or ask the supplier for the aquatic safety data. Many materials that are transported and could get into streams or sewer system via a spill are tested for toxicity to fish.

What ever route you take for your colored PVC, I would test before puting it in the public domain.

[mantid51]

Thanx to all who responded to my query. I ended up trying Ritt dissolved in acetone (because acetone is miscible with water) and dyed some pvc successfully. After outgassing, soaked for a week in salt water without any leaching. Since all I need is cosmetic effect, and the field aquariums won't even be used for more than a few hours at a time to hold and observe critters, I think I've got a winner. All machining is done before glue-up, so acetone won't be able to affect the acrylic faces.

Apparently, the acetone carries the pigment into the surface layers of the polymer where it is inaccessible to water and can't leach out. That's my story an' I'm stickin' to it!

Thanx again, Mantid