In Great Britain, Dunlop used to make zippered "matress boxes" out of cotton covered red double sided rubber, to go over their DUNLOPILO matresses for the National Health Service, but they were discontinued in the late 60's because they are a fire hazzard.
They would ignited, often from smouldering bedclothes due to a cigarette, and then burn fiercely, whereas a PVC one would only melt, but not catch fire.