There are many processes in textile printing and dyeing production, such as dyeing, printing, and applying chemical oils. In these processes, foam is produced during printing and dyeing, especially in the occasions where the stirring effect is intense, such as high temperature, high pressure jet overflow dyeing and other processes, the foaming is particularly intense. The production of foam can easily cause the fabric to float, uneven dyeing and other problems, so the use of defoaming agent is also particularly important.
Ⅰ. Features of defoaming agent
1. Fast defoaming and good foam suppression performance.
2. It does not affect the basic properties of the foaming system.
3. Good diffusibility and permeability.
4. Chemical stability.
5. No physiological activity, no corrosion, no toxicity, no adverse side effects.
6. Non-flammable, non-explosive, high safety.
Ⅱ. Classification of defoaming agent
Generally speaking, the textile printing and dyeing defoaming agent can be divided into: organic defoaming agent and polysiloxane defoaming agent (usually called silicone defoaming agent).
1. Organic defoaming agent-liquids with low surface tension that are insoluble in water. The use concentration of this type of defoaming agent is relatively large, about 0.1%-0.4%, and the defoaming effect is often not easy to last.
2. Polysiloxane defoaming agent-the main composition is polydimethylsiloxane of molecular weight; in addition to the above six advantages, the low concentration of this type of defoaming agent is another feature. In solution when the content is 1-60ppm, it can play a good and long-lasting defoaming effect, so it is especially suitable for high temperature and high pressure jet overflow dyeing industry, because in this case, dyeing is carried out at high temperature and vigorous stirring.