ABSTRACT
High resiliency moulded foam is normally tested under standard laboratory conditions, e.g. 23 ± 2°C, 50 ± 5% RH but other conditions may be specified. It is well known that critical foam properties such as hardness and resiliency are influenced by environmental changes. This may affect foam performance especially in automotive seating applications. Changes in seating support, durability and comfort may occur and critical safety components such as occupant sensors may be affected.
We have measured property changes that result from different climatic conditions from −30 to +95°C and 0 to 95% RH. A number of foam chemistries both experimental and in worldwide production have been thoroughly examined for property responses after conditioning. Cushion hardness, hysteresis loss and thickness have been shown to change after environmental conditioning. Resiliency as measured by ball rebound also responds to climatic changes. We have analyzed our extensive data for temperature or relative humidity responses and for the combined response to both of these variables. Also we are able to demonstrate combined responses of properties that contribute to seating comfort as a function of climatic conditions. Therefore, we are able to demonstrate to automotive seating designcrs/engineers the temp/RH ranges where an important cushioning parameter such as seating hardness (and hence H-point) is relatively consistent Thus, important safety components such as occupant seating sensors should remain functional over a relatively wide range of climatic conditions. Seating of various constructions, e.g. metal pan, flexible suspension, sinespring wire, have been tested to ascertain foam responses specific to these constructions. Full details of foam seat performance after environmental conditioning will be discussed.
