Latex is an adhesive material applied by the carpet or rug manufacturer to anchor tufts to the back, give additional weight and to hold the backing onto the rug.
Latex starts to deteriorate as soon as it is put into service, similar to the rotting of automobile tires, elastic bands in garments and rubber bands. The breakdown is caused by gases in the air, floor waxes, traffic and sunlight.
A complex mixture, latex contains many chemicals affecting both its wear properties and cost. Chemicals are added to latex in an effort to retard this breakdown, but cannot prevent its taking place. Other chemicals are added to reduce cost. Such chemicals could be compared to gravel in a concrete mixture; they take up space but have no adhesive properties. Increased use of this material reduces the adhesive power of the latex, causing an earlier breakdown and, therefore, a separation of the backing from the rug.
The more expensive latex compounds will better withstand aging as well as cleaning, but even these will deteriorate eventually. The rate of the deterioration is influenced by the ingredients of the rubber mixture as well as the conditions under which it is used. This breakdown will not take place evenly, but will appear in smaller areas in the form of "bubbles" or separation. In many cases, it is more apparent along the rug edges exposed to gases in the air.