| Abstract: | A new method is described for the measurement of foaming under laboratory conditions, which permits measurements to be made from room temperature up to 140d? Con liquors which can be taken through a simulated high-temperature (HT) dyeing cycle. Results obtained by this technique show that: - 1 There is a universal tendency for foaming to decrease as the temperature is raised, and to become insignificant under HT conditions.
- 2 The solid forms of disperse dyes usually give much greater foam volumes than the liquid forms of the same dyes at the same concentration of dye.
- 3 Marked differences are found in the tendency of different dispersing agents to foam.
- 4 Existing antifoaming agents of the silicone emulsion type are effective defoamers in the early stages of the dyeing cycle, but lose their effectiveness after a period at top temperature, so that there is little control of foam by this type of product on cooling back to below the boil.
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