No abstract

Comfort is a major selling point for clothes, and tactile comfort is essential; a fabric must be pleasant to the touch. Several textile finishing processes improve fabric touch: sanding (or emerizing) (for 30% of clothes) and raising (for polar fleece, a current popular product), for example. There is no current control system for these processes, which are very often used but not well understood. This study describes a tribological method for investigating sanding and raising, and brings to light the effects of these processes on the fabric surface. A textile fabric is rubbed with a probe of a multidirectional roughness meter, and the signal is studied in the frequency domain. The calculated autospectrum shows several peaks that correspond to the kind of weave or knit and the fabric density. The peak height changes with the process intensity and decreases after sanding or raising, due to a modification of the fabric profile. The multidirectional roughness meter provides information about the fabric surface state and the fundamental directions of fabric relief, which depend on the kind of weave or knit. Observations with a scanning electron microscope and edge extraction of hairs produced by sanding or raising are used to interpret this information.

No abstract

Data analysis of the compression of a fabric can only be done using a mathematical model to smooth the results. The best formula is Van Wyk's, although the meaning of the physical parameters is very difficult to define for a fabric. On the basis of Van Wyck's equation, a study of the compressibility of a fabric whose weft is made of multiple threads (classic ply-yams, open-end, combed or carded) shows that the struc ture of a fabric has a higher value than the structure of a thread. The mechanical properties of a fabric are supposed to be essentially due to its construction and, to a lesser extent, to the threads from which it is made.

We present the results of systematic model experimental investigations on wrinkling instabilities which develop on alginate-based coatings when they are wetted by swelling electrolyte drops. The wrinkles first appear randomly within the wet spot, before they selectively protrude out around the periphery in a quasiperiodical wrinkle pattern. We discuss the critical parameters that drive the emergence (ionic strength and swelling rate) and spatial feature (size and periodicity) of these swelling-induced structures on such complex functional coatings. Beyond their relative aesthetics and their fundamental interest related to morphological instabilities, these reconstruction structures which are invisible to the naked eye can develop in a variety of technological processes (inkjet printing for instance), affecting irreversibly the quality of the products.