Several types of dryer fabric softeners have been available. One type of dryer fabric softener is available as a dryer sheet. The dryer sheet is placed in the dryer along with wet laundry. The sheet is often a nonwoven fabric containing a solid composition that includes a fabric softener and a fragrance. During the drying cycle, the temperature increases as the laundry dries, causing the fabric softener to melt and transfer from the nonwoven sheet to the laundry. Dryer sheets are generally provided for a single use. If the dryer sheet becomes entangled with an article of laundry, excessive deposition onto that piece of laundry may result in “spotting.” Spotting is the condition where concentrated fabric softener causes a dark spot on a laundry item. For certain dryer sheet products, it is believed that dispensing of the fabric softener is primarily caused by the heat of the dryer melting the fabric softener on the dryer sheet. It is believed that this mostly takes place near the end of the drying cycle when the temperature within the dryer increases.
Dryer sheets containing fabric softeners are described by U.S. Pat. No. 3,442,692 to Gaiser; U.S. Pat. No. 3,686,025 to Morton; U.S. Pat. No. 4,834,895 to Cook et al.; U.S. Pat. No. 5,041,230 to Borcher, Sr. et al.; and U.S. Pat. No. 5,145,595 to Morris et al.
Another type of dryer fabric softener is available as a pouch containing a fabric softener composition. The pouch can be attached to the dryer drum. During the drying cycle, the increase in temperature can melt a portion of the composition inside the pouch. The melted composition then passes through the pouch and transfers to the laundry. The pouch type dryer fabric softener can be available for multiple uses. An example of the pouch type dryer fabric softener was available under the name “Free 'N Soft” from Economics Laboratory of St. Paul, Minn. Examples of pouch type dryer fabric softeners are disclosed by U.S. Pat. No. 3,870,145 to Mizuno; U.S. Pat. No. 3,967,008 to Mizuno et al.; and U.S. Pat. No. 4,098,937 to Mizuno et al.
Additional fabric softener compositions are disclosed by U.S. Pat. No. 3,972,131 to Rudy et al. and U.S. Pat. No. 4,035,307 to Fry et al.