Overview of Liquid Fabric Softeners
Clothes lose some of their original mechanical properties because of the intense stress they experience during laundering, and the textile fibers tend to entangle. Through the drying process, the fibers remain entangled and clothes become stiff. Items made with manufactured fibers tend to get charged with static electricity during tumble drying causing static cling. The use of liquid softeners in home laundering helps eliminate these issues.
Liquid softeners were born in the early 1960’s as simple dispersions of ditallow dimethyl ammonium chloride (DTDMAC), fragrance, electrolyte, colorant, and water. A softener’s active compound or ingredient which is highly water insoluble exists as a vesicle, a bilayer structure, in water. DTDMAC was very effective as a softening and antistatic agent and was cost effective.
All effective home laundry liquid fabric softeners contain a cationic surfactant—a quaternary ammonium compound.
Liquid fabric softeners function by depositing cationic active compounds or ingredients onto fabric surfaces during the rinsing cycle. Dialkyl quaternary softening agents consist of a positively charged amine group and fatty chains. Once the quaternary active attaches to the fabric, the fatty chains orient themselves perpendicular to the fabric surface. This helps prevent fibers from becoming entangled creating a thick, full density. Full fiber lubrication creates less friction on the surface and in between fibers providing a soft hand/feel to fabrics.
A softener’s active ingredient or compound deposition in the rinse cycle can be very high, approaching 90% in some cases. The rinse deposition provided by a liquid fabric softener provides an advantage over dryer sheet softener deposition, as liquid softeners have greater exposure to the fabric surfaces, thus deeper penetration potential to provide a softer hand/ feel. Softer garments provide consumers with the perception of increased tactile comfort during wear.
When clothing is dried in a machine dryer, items made of fibers that naturally contain some moisture like cotton can dissipate charges better than items made of manufactured fibers like polyester. Fabric softeners reduce friction by lubricating fibers, which helps to minimize static buildup in the dryer. In addition, due to the better conductivity properties of softener’s active compounds or ingredients, their use can help neutralize the build up of electric charges generated in a dryer from mixed fiber content loads.
Most all fabric softeners (except the unscented or “free” versions) provide freshness to fabrics by fragrances incorporated into the formulations. These generally provide a fresh dry fabric scent that in some cases can last for several days. Many consumers correlate a fresh wet and dry fabric scent with an impression that an item is fully clean.
The use of liquid fabric softeners usually results in better color appearance of laundered fabrics. The deposition of the softening component lubricates fibers and yarns which reduces fabric abrasion that helps maintain fabric appearance and possibly extends the life of the fabric. Fabric abrasion may cause surface disruptions, such as fuzziness and/or pilling, that can contribute to a faded, worn appearance.
Due to the fiber lubrication and reduction in fiber-tofiber friction from deposited softener active ingredients, liquid softeners help reduce fabric wrinkling. Less wrinkling helps make garments easier to iron.
Liquid fabric softeners are not recommended for use on children’s sleepwear or garments labeled as flame resistant as the softener may reduce flame resistance.
In the mid1980’s, manufacturers converted many liquid softeners to compacted “ultra” formulas by concentrating the active level about three times resulting in smaller, more convenient bottle sizes. To maintain the desired softness performance, manufacturers used combinations of DTDMAC with amidoamine quaternary active ingredients, imidazolinium quaternary active ingredients, or imidazolines.
