Emulsion Packing
ANIONIC BITUMEN EMULSION
Anionic Bitumen Emulsion, the tiny droplets of bitumen are electronegative recharged. In Cationic bitumen emulsion the tiny droplets of bitumen are electro positively charged. The average and commonly used between emulsions is cationic between emulsions. Selection of positive or negative recharge between emulsions depends upon the mineral composition of aggregate on which it is used Ex: In case of silica rich aggregates the surface of silica is aggregate is positively charged therefore cationic bitumen emulsion is used which helps in better spreading and binding of bitumen with aggregates.
APPLICATION OF EMULSION ANIONIC
Anionic Bitumen Emulsion application involves the application of negatively charged drops of asphalt to a negatively charged surface. All of the components resist one another. The only way for the emulsion to break is through water evaporation. As more water evaporates, the particles are forced closer and closer together until they can no longer be separated by a water film. At this point, droplets congregate into larger and larger drops, eventually forming a sheet of asphalt on the road.
REASONS TO USE ANIONIC BITUMEN EMULSIONS OVER CATIONIC EMULSION
The Anionic Stable Grade Bitumen Emulsion, also known as the SS60, is a versatile and forgiving product. Compared to its cationic countertype, the CSS60, the SS60 has several advantages. The 5 top-of-mind reasons to select anionic bitumen emulsions instead of cationic emulsions for slow set applications are:
- Cationic emulsions are corrosive,
- Anionic emulsions are safer,
- User-friendly,
- Storage stable, and
- Eco-friendly.
1) CATIONIC EMULSIONS ARE CORROSIVE
The anionic SS60 has an alkaline pH typically between 11 and 12. On the other hand, the cationic CSS can have a pH as low as 1. In other words, CSS is highly acidic. With an acidic pH, cationic emulsions have a tendency of devouring mild steel parts of emulsion mills, pumps, and tanks. Another victim of the corrosive pH is its steel drum packaging.
2) ANIONIC EMULSIONS ARE SAFER
With CSS being highly acidic, it is also not as user friendly and safe as anionic emulsions. Of course, in both cases it is advisable to use the appropriate personal protective equipment (PPE). However, the low pH of cationic emulsions warrants additional care, whereas anionic bitumen emulsions have been proven to be safe for use in the waterproofing of fishponds. When it comes to protecting human workers and animal life, anionic emulsions are the better choice.
3) ANIONIC BITUMEN EMULSIONS ARE USER-FRIENDLY
This type of emulsion is more suitable for handwork and labor enhanced construction practices. Anionic emulsions are an excellent example of user-friendly bituminous products that have a long track record of gainfully employing local laborers. There is a large focus on job creation and enabling women in the road construction industry. These men and women perform essential maintenance, construction of slurry seals and penetration McAdam construction techniques on their local road system.
4) ANIONIC EMULSIONS ARE STORAGE STABLE
Because anionic bitumen emulsions have a long shelf-life, many engineers consider it more suited for transport into remote locations than their cationic countertype. This knowledge stems from years of practical experience. Also, the product has earned the reputation of best choice for use in rural and remote road construction. In such places, the surrounding infrastructure is often insufficient, such as appropriate storage conditions. Also, construction rates are slow. Thus, anionic emulsions are the most appropriate choice here.
5) ANIONIC EMULSIONS ARE ECO-FRIENDLY
Our planet is facing huge climatic and pollution challenges. Anionic bitumen emulsions are manufactured with emulsifiers originating from natural and renewable resources. The resin-based emulsifiers are responsibly harvested from oxygen producing trees. Thus, they promote the protection of trees with the eco-friendly production of emulsions.
ANIONIC AND CATIONIC WATER BASED EMULSIONS
An emulsion can be Anionic, Cationic, and Non-Ionic. An Anionic emulsion has a negative charge, a Cationic emulsion has a positive charge, and a Non-ionic emulsion has no charge. Most of the things in the world are Anionic and that is why the majority of Research and Development, formulating, and lab testing has been done in the Industrial Coatings Industry to make coatings from Anionic systems. When an Anionic emulsion is mixed with a Cationic emulsion a strong bond develops and the result is the changing of the substance to a solid. This result is not ideal to be used as a coating because it cannot be applied to substrates. When you apply a Cationic emulsion to an Anionic substrate there is usually better adhesion. Therefore, a Cationic emulsion tends to have better adhesion properties than an Anionic emulsion because of the positive charge. Anionic emulsion is alkali soluble so therefore susceptible to dissolving by high pH or alkaline detergents. Cationic emulsion will not dissolve that easily in alkaline solutions or alkaline detergents. Anionic emulsions will have very good resistance to acids. Cationic emulsions will readily dissolve in acid solutions once the film is dry. Emulsion polymers usually dry faster and in certain cases this is not ideal. An example is in gravure printing where a cylinder is rolled through ink to print onto the intended substrate. The company that is using the ink doesn’t want to have the ink dry up quickly on the cylinder. In this case an ink chemist may choose to add a calculated amount of a solution to the Cationic Emulsion to increase the open time and create better flow for printability. With that added solution the emulsion will provide the print with excellent resistance properties, but sometimes adding a solution can reduce resistance properties and separate other chemicals from the emulsion.
BREAKING CHARACTERISTICS OF ANIONIC BITUMEN
Emulsions exist for ease of application. After application the water to should evaporate and leave the asphalt cement. In a surface treatment, after emulsion and aggregate have been applied to the road surface, the emulsion should “break” leaving the asphalt cement holding the aggregate. At that point traffic may be allowed on the surface without loss of aggregate. The type of emulsion used has a large effect on the speed of the “break” of an emulsion. Almost all surfaces have a net negative charge. The strength or intensity of this negative charge may be different from material to material. Because of this phenomenon, anionic and cationic emulsions break in different ways. In an application of anionic emulsion, negatively charged drops of asphalt are applied to a negatively charged surface. All components repel each other. The only way the emulsion can break is through the loss of water by evaporation. As more and more water is lost through evaporation, the particles are forced closer and closer together until they can no longer be separated by a film of water. At this point, droplets coalesce into larger and larger drops and ultimately a sheet of asphalt on the road.
