Secondary Backing Systems for Carpet

Carpet after being dyed is send for the secondary backing. Here the surface is smoothened and backing is applied. The secondary backing provides dimensional stability while locking individual tufts in place.

The application is easy. It is simply glued to the primary backing with latex. The latex is usually styrene-butadiene synthetic rubber (SBR) compounded with large quantities of powdered filler such as chalk. It has milky appearance. Chemical 4-PC, a by-product of the latex lends the carpet a smell peculiar to new carpet.

It is on the back of the carpet that the latex is applied. Carpet is made to pass through the puddle of latex. Latex is forced down by the blade around all the yarn on the back of the carpet, which locks the yarn into the backing. A second coat of latex is applied thereafter which holds the secondary backing onto the tufted material. This gives the carpet a dimensional stability.


After the completion of gluing of the primary and secondary backings, the carpet is sent to an oven to cure the latex. The Dimensional stability, imparted by the secondary backing, enables the carpet to retain its size and shape after installation.

Secondary backings used today are mainly woven polypropylene which is made of a leno weave of slit film and spun olefin yarns that forms a stretchable, all synthetic secondary backing fabric. The secondary backings are also made of Jute. However jute backings has several major problems, such as potential for browning and rotting.

Some of the secondary backing acts as a moisture barrier. These are commonly made from solid vinyl or urethane. The objective of this backing is to keep water-based spills from penetrating through the carpet. However, these backings also have certain disadvantages. They can trap any moisture trapped under them from evaporating. This can prove harmful to the concrete itself. This can also harm the glue if the carpet is glued down and fail the carpet installation. Since the pad does not absorb a spill, or pet urine, the material tends to spread outward more, making wicking over a larger area more likely. Some of the carpet backings have soft impervious polyethylene backing which traps the liquids where they can be found and cleaned thoroughly before soaking into the padding and through to the floor.

Carpet backings without latex are also being produced by some manufacturers. This system eliminates delamination and gives carpet lighter weight, greater flexibility, easier installation, and more easily recycled. This also eliminates the "new carpet odor".

A polymeric resin is used by the manufacturers in the finishing process. The resin in the heat and curing chamber reacts and creates a foam-like texture in curing chamber. This type of backing encapsulates the yarn for extra tuft bind with a cushion attached and also gives water repellency to provide a moisture barrier.

Carpet backings with urethane system functions as both the adhesive and the secondary backing and adheres to the back of the carpet by reacting with it. This system also acts as a moisture barrier which protects sub-floors and reduces wicking from spills. The Enhancer system of the backing protects the carpet against edge ravel, pilling and fuzzing.

Carpet backings with urethane system functions as both the adhesive and the secondary backing and adheres to the back of the carpet by reacting with it. This system also acts as a moisture barrier which protects sub-floors and reduces wicking from spills. The Enhancer system of the backing protects the carpet against edge ravel, pilling and fuzzing.