Vicat softening temperature of plastics is the temperature at which a standard flat ended indenter penetrates one millimeter into the surface of the material under test under a specified load.The test is conducted by placing a test specimen taken from the sample under test on a flat platform inside a liquid bath and applying compression load over its upper face through a flat ended indenter.The load is applied by placing dead weights on the upper end of the indenter. After the test specimen attains the temperature of the bath, the bath temperature is increased gradually till the indenter penetrates by exctly 1 mm into the test specimen.The bath tempera- ture in deg C at which this happens is recorded and reported as the vicat Softening temperature of the sample under test. The Vicat softening temperature apparatus for plastics consists of a hinged metallic frame which serves as support for the test specimen.The frame is fitted with a bush for supporting a rod carrying a hardened indenting tip at its lower end and a loading platform near its top to place the weights on. A dial gauge is fitted at the upper end of the frame to measure the movement of the rod.The whole assembly can be immersed in a liquid bath consisting of a glass beaker heated with the help of anelectric heater cum magnetic stirrer having provisions for controlling the rate of heating and stirring independently. The bath has a thermometer to measure its temperature. The hinged frame is mounted over a casted base. The base is finished in Dark grey hammertone painting and the other components are bright chrome/Zinc plated to give a corrosion resistant finish.The parts which are immersed in the bath during the test are made from brass. The indenter is made from high speed steel. TECHNICAL DATA : Size of test specimen : 12 x 12 mm x 3 to 6.4 mm thick Area of indenting tip : 1 mm2 Length of indenting tip : 3 mm Load on the tip : 1 Kg or 5 Kg. Dial gauge : 0 -10 mm x 0.01 mm
Specification for Rigid PVC sheet IS 10810 - 1984 : Methods of test for cables Part 22 : Vicat softening point ASTM D 1525 - 1982 : Vicat softening temperature of plastics BS 2782 - 1970 : Methods of testing plastic method 102 D, 102 F, 102 J : Vicat Softening Temperature.