The use of organosilicone as spray dyeing defoamer has been reported in many literatures. The old dyeing process, the general application of dimethyl polysiloxane defoaming agent, can achieve satisfactory defoaming agent effect, and ensure the uniform dyeing. The new dyeing process, however, uses high-temperature and high-pressure machinery, in which the dye is moved by a jet of dye fluid and is dyed at the same time. Although the resulting foam can be defoamed by ordinary silicone defoaming agents, but at high temperature and pressure, the general siloxane defoaming agents will produce thin film precipitation and make the stained material produce spots. The use of block copolymers can overcome these disadvantages because the components of the defoaming agent are soluble in cold water rather than in hot water, so they have an antifoaming effect. However, the defoaming effect of only using this copolymer defoaming agent is not satisfactory. If a certain amount of fog SiO2 is added to the copolymer, the satisfactory defoaming effect can be achieved and the fabric with uniform dyeing can be produced.
Polyether modified silicone defoaming agent is easy to emulsify in water, also known as "self-emulsifying defoaming agent". When the turbidity point temperature is above, it loses its solubility and mechanical stability to water, and is resistant to acid, alkali and inorganic salts. It can be used for defoaming under harsh conditions, and is widely used for defoaming in the high temperature dyeing process and fermentation process of polyester fabric. In addition, it can also be used in the defoaming of diethanolamine desulfurization system and various oil agents, cutting fluid, non-freeze liquid, water-based ink system and other defoaming, also suitable for the printing industry photosensitive resin plate making, wash off the uncured resin defoaming, is a very representative, excellent performance, widely used silicone defoaming agent.
In order to improve the lipophilicity for water-based inks, coatings and cutting fluids, part of methyl group in the copolymer molecules of polyether modified silicone is replaced by long-chain alkyl group, which can play a more effective role in the defoaming effect. In order to have better defoaming ability below the turbturbity-point temperature, commercial self-emulsifying defoaming agent is usually equipped with dimethylsilicone oil -- white carbon black paste, then the polyether-modified silicone surface active agent can be used as the emulsifier of dimethylsilicone oil and play a dispersing and emulsifying role under the turbturbity-point temperature.