For high-quality consumer tissue products, 100% virgin fiber is normally utilized, and the tissue machine former often has layering capability such that a hardwood fiber (eucalyptus for the softest products) is put in the outer (consumer-facing in the finished product) layer. Both secondary and virgin fiber are used in TAD tissue. The system for production of TAD tissue starts with fiber selection and pulping in a manner similar to the wet-pressed tissue machine. As a result, in places like Europe where energy prices are relatively high, TAD tissue machines are far less common than in North America where energy is relatively inexpensive. This makes TAD drying operations more energy intensive than wet pressing.

The high energy consumption is mainly due to the fact that the non-compressive dewatering means the drying is accomplished by hot air being pulled through the sheet, rather than pressing the water out. Despite the advantages in product quality, the TAD process suffers from the drawback of having high energy consumption compared to wet pressed. Since fiber is usually the highest cost element in a tissue product, reduced fiber cost is the major advantage associated with the use of TAD technology. Improved durability via increased CD stretch is also valuable for tissue products, and TAD machines are thus utilized by some manufacturers, particularly Procter & Gamble, for facial tissue production.įiber savings are possible for TAD tissue since the basis weight of the sheet can be reduced thanks to the higher bulk. Higher bulk allows the manufacture of a large-diameter and firm roll with less fiber compared to wet-pressed tissue and higher absorbency leads to a preferred product, since absorbency is a key property for both bath tissue and paper towels. The improvement in the product properties of bulk and absorbency make TAD tissue production particularly suitable for rolled tissue products such as bathroom tissue and paper towels. Even private label producers are installing TAD machines, indicating the technology has become standard, at least in North America. In North America more than 30% of the tissue production is now done on TAD machines, and several new machines are currently being installed. Among these improved properties are bulk, CD stretch and absorbency. The use of these non-compressive water-removal technologies results in a product with improved properties. There are usually two non-compressive water-removal operations used on the TAD machine: Vacuum dewatering and Through drying.

The principle components in the TAD tissue making system are illustrated in Figure 1. In this process, the web is dewatered and dried by non-compressive means, thereby avoiding the compaction that occurs during wet-pressing of the web in the conventional process. This is often called the “conventional” process because of its widespread use throughout the world (see more here Conventional)īut there is a second process, called “Through-Air Drying” (TAD), that has become a second standard technology over the last two or three decades. Through Air Drying (TAD) tissue making technologyĭry-crepe tissue technology, which involves pressing of the sheet when it is in a wet state, is the most common method of tissue manufacture.

Tad meaning