Easy-care and durable press finishes are generally applied to cellulose and cellulose blends fabrics, but other fibers can benefit from these finishes. There are many words and phrases available to describe this application;
- Durable press
- Minimum care
- Easy to iron
- Wash and wear
- Crease resistant
- Permanent press
- Shrink proof
- Wrinkle resistant
- Wrinkle free
The most technically correct description would be "Cellulosic anti-swelling" or "Cellulosic cross linking" finishes.
In addition to the dimensional stability properties, the sheen of calendered fabrics (permanent chintz) and the stand and hand of pile fabrics are generally improved by resin finishes.
The primary effects of easy-care finishes on cellulose are:
- Reduction in swelling and shrinkage
- Improved wet and dry wrinkle recovery (*CRA)
- Smoothness of appearance after drying.
- Retention of intentional creases and pleats.
* CRA (crease recovery angle), is the sum of the crease recovery angles of warp and the fill directions of the fabric, increases from about 1500 to about 3000
An unavoidable side effect of the cellulosic crosslinking finishes is reduction in elasticity and flexibility of the cellulose fibers. This produces a considerable decrease in abrasion resistance, tear and tensile strength on cellulose.
Mechanisms of easy-care finishes
The primary cause of shrinkage of cellulosic fibers is the fact that these fibers can readily absorb moisture. This absorbed moisture facilitates internal polymer chain movements in the amorphous fiber areas by lubrication. It disrupts the internal hydrogen bonding between these polymer chains. When a moisture laden cellulosic fiber is stressed, the internal polymer chains of amorphous areas are free to move to relieve that stress. Hydrogen bonds can reform between the polymer chains in their sifted position. With no restoring forces available, a newly formed wrinkle or crease will remain until additional processes (ironing for example) apply adequate moisture and mechanical forces to overcome the internal forces.
The swelling of cellulosic fibers by moisture can be reduced by application of self crosslinking king urea or melamine products as well as products that mainly crosslink with cellulose molecules.
Without such a crosslinking finish, cellulose fibers can take up more than 10% of their weight in water. As the fibers swell, the fabric must crease and shrink to relieve the internal stress caused by swelling.