Monday, October 22, 2012

White Isn't Always White

Today's post isn't about polymers per se but about additives for polymers. With the exceptions of pigments and dyes, the manufacturers of most additives strive for a lack of color in the their products, with Nirvana being "water white". This has always struck me as a strange term, and newcomers to the industry need to have it explained to them the first time they hear it, but "water white" does not refer in any way, shape or form to "white", but rather to the "water" aspect - they are as clear as water.

The term is most commonly used for petroleum-based products, and often the "water" is dropped so that we are left with such liquids as "white oils", "white mineral oils" and "white gas". There are many hydrocarbon-based resins (polymerized olefinic materials of low molecular weight, often used as tackifiers) that are sold as "water white", but the term is even used to sell modified rosin compounds that are nearly colorless when molten.

I'm not having any luck finding the origin of the term, but given that it came from the petroleum industry that is used to working with liquids that are as black as anything you can find, I can imagine that liquids that are purified as much as possible could be "white". Any other ideas?

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