A property of paper describing its ability to resist fading, discoloring, or deteriorating when exposed to alkaline (low-pH) substances such as soaps and adhesives. Alkali resistance is an important property when a paper is intended to be used in the packaging of such materials.
The term alkali resistance also refers to a similar ability of a printing ink to resist bleeding, discoloring, fading, or chemically reacting with alkaline materials. Inks intended for use in the packaging of soaps or other alkaline materials need to possess high alkali resistance. (See Pigment.) (See also Soap Resistance.)