The Kawabata Evaluation System (KES) is used to make objective measurements of hand properties. The KES instruments measure mechanical properties that correspond to the fundamental deformation of fabrics in hand manipulation. Five different tests can be performed using KES and the main mechanical characteristics produced, are described below.
The Kawabata system of instruments, featured in the fabric hand laboratory, measures properties of textile fabrics and predicts the aesthetic qualities perceived by human touch. The Kawabata Evaluation System (KES) includes five highly sensitive instruments that measure fabric bending, shearing, tensile and compressive stiffness, as well as the smoothness and frictional properties of a fabric surface. This evaluation can include measurement of the transient heat transfer properties associated with the sensation of coolness generated when fabrics contact the skin during wear. KES provides a unique capability, not only to predict human response, but also to provide an understanding of how the variables of fiber, yarn, fabric construction and finish contribute to the perception of softness. A standard specimen size of 20 x 20 cm is used in three replications. All measurements are directional, except for compression, and are made in both the lengthwise direction, and in the crosswise direction of the sample. Appropriate instrument settings are used for the material being tested.
Scientifically designed protocols used to determine subjective ratings or rankings of fabric softness are also conducted in the laboratory. These studies analyze tactile response to the texture, softness, and other hand properties of fabric materials. Human panel evaluations, used in conjunction with the KES are useful for engineering desirable hand qualities into textile materials.
The system was developed by a team lead by Professor Kawabata in the department of polymer chemistry, Kyoto University Japan. The initial work started in 1968 and the system became commercially available in its present form since 1978.
The system was originally aimed at the objective evaluation of fabric hand, but the sensitivity and comprehensiveness of the tests offered by the system led to its widespread application in other areas such as product, process development process control.
The authors are associated with Applied Chemistry Research Centre (Textile Section), PCSIR Laboratories Complex, Off University Road, Karachi, Pakistan