I've been trying to research what kind of tile was originally used in the kitchen and laundry room area of my house and I believe it might have have been KenFlex vinyl flooring. Unfortunately KenFlex doesn't manufacture floor tiles anymore and according to some information I found online KenFlex tile might contain unhealthy levels of asbestos which can become problematic if the tile is damaged and in need of repair (which is the case in many areas of my home).
I'm not sure how we're going to deal with the current floors since the kitchen is a real mess and most of the original tile has been covered up or removed and replaced by some rather ugly stuff that was probably manufactured in the '90s. We may be able to save the floor in the laundry room but we won't really know until we can get in there and start working on the place.
In the meantime I thought I'd share some original ads (published 1953-56) for KentFlex flooring. Just click on the images to see larger full size versions of the ads.