Protective apparel includes coveralls, gowns, smocks and other garments whose purpose is either to protect a wearer against exposure to something in the wearer's surroundings, or to protect the wearer's surroundings against being contaminated by the wearer. Examples of protective apparel include suits worn in microelectronics manufacturing cleanrooms, medical suits and gowns, dirty job coveralls, and suits worn for protection against liquids or particulates. The particular applications for which a protective garment is suitable depends upon the composition of the fabric or sheet material used to make the garment and the way that the pieces of fabric or sheet material are held together in the garment. For example, one type of fabric or sheet material may be excellent for use in hazardous chemical protection garments, while being too expensive or uncomfortable for use in medical garments. Another material may be lightweight and breathable enough for use in clean room suits, but not be durable enough for dirty job applications.
The physical properties of a fabric or sheet material determine the protective apparel applications for which the material is suited. It has been found desirable for a wide variety of protective garment applications that the material used in making the protective garment provide good barrier protection against liquids such as body fluids, paints or sprays. It is also desirable that the material used in making protective apparel block the passage of fine dirt, dust and fiber particles. Another group of desirable properties for fabrics or sheet materials used in protective apparel is that the material have enough strength and tear resistance that apparel made using the sheet material not lose its integrity under anticipated working conditions. It is also important that fabrics and sheet materials used in protective garments transmit and dissipate both moisture and heat so as to permit a wearer to perform physical work while dressed in the garment without becoming excessively hot and sweaty. Finally, most protective garment materials must have a resilience that allows them to recover their shape when crushed or otherwise distorted. Recovery after crush is a measurement often used for resiliency. In the context of the present invention, resiliency includes both elastic and plastic deformation as long as the material substantially recovers its original shape and essential properties after the stress gradient that is the cause of the crush has been removed.
Bonding of fabrics to form garments may require fusion of the fabric material with other materials. Such fusion is easier with a material that has a reduced crystalline structure. What is needed therefore is a fabric with a high resilience, as evidenced by crush value, and a lower crystallinity than heretofore available so that bonding with other layers is enhanced. There are multiple situations where the deformation can occur while positioning or using the material of interest. It is then desirable that the material recovers its original shape and essential properties.