Within the range of chemical specialties that Concentrol makes, emulsions and dispersions have become one of the most important families. They are products that have often been developed to solve specific problems, with a high degree of specialization, often with close collaboration with our customers and that have been adapted to different chemical and industrial sectors.

Emulsions are products that typically contain a water-insoluble liquid, water and emulsifiers, so that a stable liquid product is obtained.

A dispersion, likewise, is a preparation consisting of a solid insoluble in water, water and emulsifiers, to also achieve a stable liquid product.

The use of water as a carrier of the insoluble active product offers clear advantages over other carriers such as solvents. For example, and this list is not exhaustive, no toxicity, no volatile polluting emissions (VOC), the fact that it is not harmful to the environment, its low cost and the safety in its handling by avoiding the use of flammable solvents.

On the other hand, achieving good stability of emulsions and dispersions is a considerable technical challenge. These have been, however, the challenges that Concentrol has willingly faced throughout its history, which has enabled us to develop the wide range of water-based products we currently market.

In the family of emulsions, those based on the chemistry of silicones have become very important. The chemistry of silicones is currently in many fields, from the control of unwanted formation of foam, to improving wetting and levelling of multiple coatings, the improvement of resistance to water, abrasion, scratching, improvements in gliding, shine enhancement, non-stick effects and other effects that in many cases are achieved with a very low dosage.

Silicone emulsions typically contain a silicone component (usually a silicone oil, polydimethylsiloxane), water and the appropriate emulsifiers. From a chemical point of view, silicone oil is a finite chain of silicon and oxygen atoms bonded to each other. Silicon itself has two unions to organic groups that in many cases are methyl groups (CH3) that confer their semi-organic characteristics to the silicone chain.

 

 

As we have said, one of the main difficulties in the world of emulsions is to achieve a product that is sufficiently stable over time. It is necessary to avoid the natural tendency to separate between the insoluble fluid (silicone in this case) and the water.

This is achieved with the selection of the most suitable emulsifier system for each insoluble fluid. The outcome thus, in the normal phase emulsions, is to obtain small silicone oil spheres enveloped by an aqueous matrix. Achieving the right size as well as a distribution of this size as homogeneously as possible are necessary requirements to achieve optimum stability in the emulsion.

Depending on the size of the particle, silicone emulsions are classified into two subfamilies, macro and micro-emulsions.

Characteristics of silicone macro-emulsions:

  • White appearance, stable emulsions with different % of silicone content
  • Typical average particle size = 0.1 to 1 micron
  • They can be formulated using silicone oil with different viscosities, being the most common 350 cps and 1000 cps
  • Once applied, when the steam has evaporated, the silicone remains on the external surfaces, where they offer benefits such as the reduction of the dynamic coefficient of friction, which provides a lubricant effect.

Characteristics of silicone micro-emulsions:

  • Transparent appearance, very stable in extreme conditions
  • Very small average size of the particles (<0.4 microns)
  • Silicone oil usually has a very high viscosity type (> 100000 cps)

Micro-emulsions of silicone are the ones that have a greater stability to dilution in water, being stable in any proportion and over time. They are also the most suitable for use as an additive in complex formulations as they have a very limited tendency to interact negatively with other components.

The EMULTROL PS-2470 silicone emulsion has shown, over the years, a number of advantages over those obtained by similar silicone emulsions, becoming a benchmark in many sectors of use.

Used as an additive in coating formulations offers improvements in slip and improved abrasion and mar resistance. It has been highly effective in acrylic, epoxy, polyester and polyurethane formulations.

Its high compatibility makes it suitable both in the let down and post-addition, in dosages ranging from 0.5% to 0.05%.

Used as a component in the formulation of adhesives of acrylic type, such as PSA adhesives that are used in the labelling of bottles and other supports, increases the performance in the stage of label cutting or converting by decreasing residue on the cutting blade. Thus, an increase of productivity in the manufacture of labels is achieved by reducing the necessary stops for the cleaning of the cutting blade.

This is achieved without any of the disadvantages that, typically, are associated with the industrial use of silicones, such as contamination, wetting problems, or defects in subsequent painting or adhesion.

The EMULTROL PS-2470 silicone emulsion is fully compatible with both acrylic dispersion and rosewood resin dispersion, and is also compatible with the rest of the usual components of adhesive formulations, such as moisturizers, antifoaming agents and biocides

Its dosing of use is between 2% and 6% relative to the total weight of the adhesive in wet, and thanks to its low viscosity, can be incorporated at any time to the formulation.

The high compatibility of the emulsion EMULTROL PS-2470, with an average particle size of less than 0.2 microns, is able to offer the advantages of a silicone fluid without any of the inconveniences that are commonly found with their use.

 

CONCLUSIONS
Water-based emulsions and dispersions are beneficial in several aspects, such as that they do not generate volatile pollutant emissions (VOC), are not harmful to the environment, they are safer when handling and at the same time are cheaper; among other advantages. For all this, Concentrol has worked with the challenge of achieving the best results with water-based products and currently sells a wide range of products with this profile.

In the case of EMULTROL PS-2470 emulsion, a product with a high compatibility and great results has been achieved that are superior to those of a silicone emulsion. This is a reference that has become a benchmark for different sectors of use and does not present any of the drawbacks of silicone products, hence their success and the great advantages of its formula.

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