Textile materials, which are different in fibre content, weave type, density and thickness, as well as multi-layered synthetic leathers, are used in soft furniture upholstery production. Deformation - relaxation behaviour, which depends on mechanical properties of such materials differs significantly, also. From this standpoint substantial problem exists in soft furniture production, because the dimensions of its upholstery patterns, i.e. initial pretention must be adjusted taking into account the differences of applied materials mechanical properties. Otherwise external view and quality of upholstery may be unacceptable due to obvious visual material excess on soft furniture surfaces, which is called pull-on ease. The aim of this investigation was to determine the dependencies between three different levels of soft furniture upholstery pre-tension and corresponding values of pull-on ease. New testing method presented in this study allows defining soft furniture upholstery deformational behaviour and its regularities in respect to the initial dimensions of upholstery patterns.

DOI: http://dx.doi.org/10.5755/j01.ms.18.4.3099

The effect of uniaxial pre-tension level upon the regularities of fused two-layer systems biaxial behaviour is analysed in this research work. Initial pre-tension of 0.0 %, 0.4 %, 0.8 %, 1.2 %, 1.7 % and 2.1 % was applied in longitudinal and transverse directions separately. Cotton fabric (100 %) of plain weave was used as a base material for the investigated systems. Biaxial punching was performed with three types of interlinings: woven, nonwoven and knitted, which differed not only in surface density, but in the density of adhesive layer, i. e. 52 and 76 dots/cm 2. The samples of fused systems were punched from the side of the base cotton fabric in order to maintain the same friction force between the punch and the specimen. The results of the investigations have shown that not only punching strength Pmax, N, and punching height Hmax, mm, differ with the increase of pre-tension level in longitudinal and transverse directions, but also different number of punching force peaks is characteristic for the investigated two-layer systems, which is related to the structure of applied interlining.

Upholstery materials during their performance experience biaxial deformations, which are effected by friction in the contact zones: material-to-human skin, material-to-material, and material-to-inner parts of the furniture. The aim of this research was to define the effect of friction in the punch-to-specimen contact zone upon the tearing character and strength of non-perforated and perforated synthetic leathers under biaxial punching. Tests were performed with three different punches. The variation of friction coefficients in the punch-to-leather contact zone was achieved by the application of four different lubricants. Leather samples were investigated on the face (vinyl) and reverse (textile) sides. The results of the investigations confirmed that the maximal punching force Pmax increases with an increase in the punch size. The same tendency is valid in cases where different levels of friction act in the punch-to-specimen contact zone or whether the specimens were punched from both sides. Dependencies exist between area S of the punch-to-specimen contact zone during tearing and the average static μSA and dynamic μDA friction coefficients.