Emulsion polymerization is a unique chemical process widely used to produce waterborne resins with various colloidal and physicochemical properties. This technique is used in the production of a wide range of speciality polymers which are used in adhesives, paints, binders for textiles, nonwoven fabrics, construction chemicals etc.
This process involves emulsification of the relatively hydrophobic monomer in water by an emulsifier, followed by the initiation reaction with a suitable initiator. The process of emulsification of monomers and stabilizing this emulsion is highly complex. Successful emulsification and its stabilization is dependent on the HLB value of the surfactant which is being used as the emulsifier. In addition to the HLB value, a variety of other factors also need to be taken into consideration while choosing an emulsifier which include the temperature at which emulsification is done, solvents used in the system, the pH at which the process is carried out among others.
Choosing the correct emulsifier for emulsion polymerization is crucial. Spectra provides a complete range of emulsifiers for emulsion polymerization. These products guarantee a high level of efficiency, consistency and provide value-added benefits.
APEO free emulsifiers for emulsion polymerization perform equally well as the APEO based products, but have an added advantage of being biodegradable. Slowly and steadily, the outlook of the industry is changing where the focus is now on developing APEO free alternatives to conventional APEO based emulsifiers. These products are based on ethoxylated straight chain and branched fatty alcohols. These products are nonionic as well as anionic.
These emuslifiers can be divided into two classes:
- Nonionic emusifiers
- Anionic emulsifiers
The primary advantages of using nonionic emulsifiers are their stability over a wide pH range and freeze thaw stability. Added benefits of nonionics are their stability to hard water and relatively less foaming character than the anionics. We have a wide range of nonionic products that encompass the entire HLB spectrum. These products are based on alkyl phenols, fatty alcohols, branched alcohols and esters. They are excellent emulsifiers which can work in both oil in water and water in oil systems. Specific products can be used at elevated temperatures, be compatible with a wide variety of solvents, or be stable at any pH.
The main function of anionic emulsifiers is to produce a stable monomer emulsion and to prevent the formation of coagulum during the manufacturing process, in order to reduce grit levels. We have a wide variety of anionic surfactants in our basket. The primary advantages of using anionic surfactants are their ability to control the particle size in the emulsion and the added stability of the so formed emulsions. These products are based on ether sulfates, sulfonates, phosphate esters and sulfosuccinates.