Study On Rheological Properties Of The Materials Used In Soft Instrument Panel

The demand for soft instrument panel used in general and luxury automobiles is increasing around the word due to its comfortable feel, uniform thickness and clear pattern.Rheological properties of silicon rubber, epoxy resin and thermoplastic polyurethane powder used to make the soft instrument panel are essential to the high clarity and fidelity of automotive instrument skins’ pattern. The main contents of this thesis are as follows:1. The silicon rubber mould is manufactured by a kind of two-component silicon rubber.Curing mechanism of the addition reaction between double bond of vinyl resin and Si-H bond of silicon oil is researched. The strain of linear regime is identified. The time sweep experiments under the multi-wave oscillatory frequency were performed to study relationship between sweep frequencies and curing time and the activation energy of the reaction is received. A right model is used to describe the curing kinetics of the two-compnent silicon rubber.2. The curing process of epoxy resin of the mould was researched. As the reaction temperature increasing, the curing rate of the two-component epoxy resin speeds up, and the cure time is short. The relationship is established between degree of cure and time. It is concluded that the curing kinetics of the epoxy resin used obey the Kamal autocatalytic kinetic model.3. Rheological properties and mechanical properties of TPU powder are researched in this thesis. The powder N1 and N2 used to make the automotive instrument skins are confirmed to be a kind of polyester-type thermoplastic polyurethane. The effect of temperature on the melting process and flowability is studied to confirm the minimum heating temperature of the mould. The flowability of N1 is higher than N2 blow 220℃,while its lower than N2 above 220℃. The mechanical properties and thermal properties are researched, the heat resistance, tensile properties and wear resistance of N2 is better thanN1, but elongation at break is less than N1, it can be concluded that the content of hard segment in N1 is more than that in N2.