SCA Hygiene Products (SCA) holds a patent on "adult incontinence products" -- that is, adult diapers. The company sued First Quality Baby Products for infringing on its patent for a disposable diaper that can be taken on and off like underwear -- think Pull-Ups, but for adults.
A Long Waiting Period
Back in 2003, SCA sent a letter to First Quality saying something along the lines of, "Hey, we think one of your products infringes on our patent." First Quality responded by saying, "Hey, actually, it looks like your diaper has the same construction as our diaper, which was patented before yours was. Looks like our patent invalidates yours. Go figure."