The backing of a carpet can often be overlooked and yet it is one of the most important factors of the carpet’s construction. A carpet’s primary backing is the depository of the face yarn. Both the primary and secondary back provide dimensional stability. A carpet with poor dimensional stability will tend to shrink and pull away from the walls, or will stretch resulting in ripples on both glue down and stretch in installations. A carpet’s backing additionally plays a very important roll in how well a carpet will seam.
Which way does the fuzzy side go?
Most everyone in the carpet business is familiar with the saying “fuzzy side up.” That fuzzy side is the “face” of the carpet. The “back” is that other side, and it can be made from a variety of fabrics, yarn, natural or synthetic materials. A carpet may have only a primary back, which is the fabric that the fuzzy material is tufted, woven or bonded into. A tufted carpet with a single back is referred to as a “single” or “unitary” back carpet. A “conventional tufted carpet” is one with both a primary and secondary back with some type of scrim or attached cushion that is laminated to it.
Back, Woven & Knitted Carpet:
The most common backing materials are jute, kraftcord, linen, polyester, olefin (polypropylene), rayon, cotton and combinations of these materials. These materials are the “construction yarns” comprising chain warp, stuffer warp, and shot or fill which are interwoven with the face yarn during the manufacturing of the carpet.
Primary Back Tufted Carpet
Primary backing materials are manufactured as both woven and non-woven fabrics in which the pile yarn is inserted by tufting, needle punching, stitching, embedding or bonding. Primary back is the carrier fabric for the pile yarn and should not be confused with secondary backing which is a reinforcing fabric laminated to the back of tufted carpet subsequent to the tufting process. Some synthetic primary backings have nylon fiber attached to their upper surfaces to make them union dyeable with nylon pile yarns.
Secondary Back “Fabric” Tufted Carpet
Usually woven jute, or woven or non-woven olefin (polypropylene). The fabric is laminated to the back of carpet (usually with latex adhesive) to reinforce and increase dimensional stability, strength, stretch resistance, stiffness, and hand. Because secondary backing is visible, whereas primary backing is concealed under the pile yarn in finished carpet, dealers and installers often refer to secondary backing simply as “backing.”
Backing Fabrics
Both woven and non-woven primary and secondary backing is made for tufted carpet. It is primarily polypropylene, but some jute and other materials are used. It is important to remember that woven backing is not the same as woven carpet.
Woven polypropylene backing presently accounts for 95% of the secondary market and 90% of the primary market. As of 1996 the secondary market was shared by Amoco and Synthetic Industries with additional companies sharing part of the primary production. Amoco is the world’s largest backing supplier with their woven polypropylene primary backing representing more than 50% of the North American primary backing and their ActionBac representing more than 50% of the secondary backing market. Polypropylene backing can now be made from recycled polypropylene and these are expected to be a player in the near future.
Spunbonded backings are made in both polyester and polypropylene. They are primarily used in the automotive industry as moldability and dimensional stability are very important. They also represent about 80% of the carpet tile and six-foot roll market. Some spunbonded is used for lower price printed loops as they create less needle deflection than woven backing.
Secondary Back Attached Cushion
This cushion is laminated to the primary back. The most common cushions are polyurethane foam, high-density foam, sponge rubber, woven fiber, latex with an embossed pattern, solid vinyl and foam-type vinyl.
Unitary Backing
A single fabric backing with high rubber content latex or hot-melt resin compound laminated to the bottom side. A unitary backing system is used to increase dimensional stability, tuft bind of the individual fibers, minimize edge ravel at seams and snagging of rows on looped pile construction.
Article from Carpet Inspectors Handbood
by Terry Weinheimer and Kevin Weinheimer
FloorCentral.com
The end user and the floor covering professional need to understand what is covered in a warranty and who the warrantor is. Often more than one warranty and more than one warrantor cover a flooring product. The company that produced the product usually offers a warranty. The company that manufactured the yarn or other components of the finished floor covering product will usually have some type of warranty. Additional warranties may include those of flurochemical companies; hardwood finish product manufacturers, distributors, cushion manufacturers, dealers, installers and others.
Using carpet as an example, a carpet manufacturer may decline a claim because they believe it to be a fiber problem. A fiber company may decline the same claim because they believe it to be the problem of the Flurochemical Company. At times an inspector may evaluate the same claim for more than one commissioning party before it is settled. While multiple inspections may appear to the consumer, as shifting of the blame, some commissioning companies unfortunately find it necessary. Where the fiber and yarn manufacturer usually handles that portion of the warranty, the carpet manufacturer covers the construction of the components used in the carpet. Some manufacturers extrude and spin their own yarn and in this case they would also cover the fiber, yarn, and construction and possibly the soil and stain resist warranty.
With all cleaning methods a wall-to-wall carpet needs to be thoroughly vacuumed prior to cleaning to remove any heavy soil such as silicates (the primary constituent of soil), without this pre-vacuuming, dirt and sand are forced to the backing of the carpet.
Absorbent Powder / Dry Extraction Cleaning: An absorbent granular material that has been incorporated into a mixture of detergent, solvent and water is brushed into the carpet pile with a machine incorporating a double cylindrical brush. Once the material has dried the carpet is vacuumed to remove the powder and the soil that it has captured. The best use for the absorbent powder cleaning method is the commercial installation where the carpet is cleaned regularly and requires quick drying.
Bonnet/Spin Pad: This method in appearance is similar to the rotary shampoo method. The machine used is essentially the same. A detergent is usually sprayed onto the carpet. A rotating absorbent pad spins and agitates the carpet fibers as the soil is collected into the pad. This method improperly preferred on cut pile carpet can cause untwisting of the face pile. While this method is reasonably quick drying it must be done more often as it is more of a surface cleaning. The best use for this method of cleaning is the commercial installation where they clean regularly and require quick drying.
Cylindrical Foam Shampoo: The cylindrical foam method uses a machine with an air compressor that whips the shampoo solution into heavy foam. The foam is brushed into the carpet with a cylindrical brush. Once the carpet has dried it is vacuumed to remove the shampoo and the particles that have theoretically bonded to it. Not all of the shampoo and soil is actually captured but instead much of it is forced deeper into the pile. While this method is reasonably quick drying it must be done more often as it is more of a surface cleaning. The best use for cylindrical foam cleaning is the commercial installation where they clean regularly and require quick drying.
Rotary Shampoo: The Rotary shampoo method uses chemicals similar to those used with cylindrical foam. The rotary floor machine usually has an attached solution tank for the shampoo solution. The diluted solution is fed through a tub to a “shower-feed” where it is applied to the carpet. While the shampoo is being applied a round brush on the machine is scrubbing the carpet. This shampoo method uses more moisture than the cylindrical brush method. The rotary shampoo method is not recommended for use on cut pile carpet as it can cause untwisting of the face pile.
Steam Cleaning or Hot Water Extraction: With this method a non-foaming detergent is injected into the carpet fibers and is almost simultaneously vacuumed out of the carpet taking the dirt and soil with it. The extraction method when performed a skilled technician and quality chemicals will leave very residue to attract to soil. In the hands of an unskilled person the carpet can be over-wet.
Optical Brighteners (color brighteners): While not a cleaning method, optical brighteners are found in some cleaning products. These brighteners or dyes can make a carpet appear cleaner while at the same time having a harmful effect on carpet fibers. Technical people in the carpet industry have unanimously taken a stand against the use of brightening agents in the cleaning process. But, even with all of the adverse publicity, optical brighteners or color brighteners, as they are often called, are still used in some spot cleaning products, shampoo, dry-foam and extraction detergents. Optical brighteners are actually dyes, which reflect the light and eventually cause yellowing in carpet fibers. For this reason alone they should not be used for normal carpet maintenance.
