Compression set of PU foam mattresses with self-clamping joints and sandwich structure
This paper deals with research on the impact of composition on compression set of the PU foam mattresses. Three type of mattress composition, with sandwich structure and self-clamping joints, were used for research. The fourth type, which contained traditional glued joint, served as a reference. During static compression of mattresses, the properties of the individual layers have been recorded or calculated, such as Young’s modulus, shear modulus and coefficient of shear friction, which were necessary for the SolidWorks simulation of the permanent deformation. The results, as well as simulations of mattress compositions, have proven that the compression set is strictly dependent on the loading time. The highest permanent deformation was recorded for mattress type A and the lowest ones for mattress type B, which had permanent deformation almost identical to that of the composition with glued joints. The last two mattress types had permanent deformation 35 % greater. It is clear from the results that the properties of selfclamping joints in upholstery can equal those of conventional glued joints. Using self-clamping joints is more advantageous in that they exclude the negative effects of glues as well as the gluing process itself.