Foam control agents are a product of a variety of chemical formulations that are used to either prevent the formation of foam or destroy the foam once it has been formed. When they are used to prevent the formation of foam, they are called anti-foaming agents and in the second case, they are called defoamers. Most of the foam control products available today are able to do both the jobs.
Defoamers are surface active agents but they are highly insoluble in water. A defoamer works by dispersing in the liquid in the form of droplets and thus forming an emulsion. When it comes into contact with the combination of air and water, its surface active properties come into play and cause it to spread rapidly within the liquid. If the liquid already contains other surface active agents, then the defoamer spreads even more rapidly.
Some anti-foaming agents contain hydrophobized silica particles or ethylene-bis-stearamide particles. They operate by piercing the surface of the foam bubbles making them cleave together to form large bubbles. These large bubbles then float to the top of the liquid and break due to external pressure. Earlier oil was the main ingredient in defoamers but due to environmental concerns, it was changed to other ingredients which are 100% active.
It is very important to use the correct dosage of defoamers. A very less dosage will not cause the action of defoamers to take place. An overdose of defoamers will affect the performance of other agents that may be added in the liquid. It also leads to the formation of very tiny foam bubbles which will be very difficult to get rid of. These agents are used in various industrial applications like the paper industry and also for food grade foam control.
Mold release agents are basically lubricating oils, solid lubricants, fluids or waxes which form a film on surfaces which prevents other materials from attaching on that surface. These agents are not like non-stick coatings which you see in pans. They are non-curing and have to be applied from time to time to be effective.
These release agents can be sourced from chemical companies who not only manufacture the agents but also market and supply them. But there are some mold manufacturers who along with preparation of molds also supply mold release agents which are specific for their products.
There are two types of release agents; non-permanent and semi-permanent. The first agent has to be reapplied after every use while the latter has to be reapplied if it comes in contact with moisture and other chemicals. The manufacturer of the agent will provide information as to how to handle and dispose the agents. They will also list its properties and how it reacts when it comes in contact with other chemicals.
Mold release agents can be used with molds that are made up of stone, plaster, plastic, fiberglass, rubber and various metals and alloys. Before you select a release agent, you need to analyze what material is the mold made up of and what technique were used to make it. One of the most popular agents is Teflon.
