Introduction
Additives are one of the important ingredients of paints, inks and industrial coatings as they can make or break the final surface performance of the product. The two most widely used coating additives are silicone emulsions and wax emulsions. Their purpose is the same- to improve the surface properties, but they work differently, perform differently and are used for different applications.
Silicone Emulsions
Silicone emulsions are additives consisting of silicone oil dispersed in an aqueous phase. It is widely used in coating formulations, printing inks, personal care products, textile, leather, indirect food contact applications, etc. Silicone surface additives are important for various industrial applications such as formulation of paints, inks and coatings. These additives possess the ability to reduce surface tension and improve wetting on various substrates which makes them advantageous for industrial applications. They are non-toxic, highly effective in low concentrations and compatible with a wide range of water-based and solvent-based systems.
Benefits and Applications of Silicone Emulsions
Wax emulsions and dispersions are formulated additives consisting of fine and stabilized wax particles homogeneously distributed in water. It is a liquid form due to which it can be incorporated in inks and coating formulations simply by mixing. The particle size of wax emulsions is generally less than 1 micron which also minimizes their effect on coating gloss. Wax-based additives and wax emulsions are most commonly used for optimizing the final performance of coatings and inks as they can efficiently control the surface properties. Typically, waxes are considered surface conditioner additives as they significantly influence the surface properties of any coatings and modify the surface free energy.
Benefits and Applications of Wax Emulsions
Wax additives are st commonly used for due to their flexibility of use and significant positive impacts on various types of formulations. Some of the important functions of wax emulsions are to include slip, rub resistance, abrasion resistance, anti-blocking and mar resistance. These functions can be achieved with the addition of a small number of wax additives. Normally, 2-4% of this amount is enough to achieve any or some of those functions. The working mechanism of wax emulsions is also known as the blooming mechanism. This mechanism allows molten wax particles to float to the surface and as the coating cools gradually, recrystallization of wax can take place by forming a thin and continuous wax-enriched surface layer. This blooming mechanism becomes more prominent as the softer the wax is or the lower the melting point is.
Wax emulsions are used in various industries and for various applications like coating of fibrous cellulosic products such as paper, corrugated cardboard, craft paper, boxboard, etc. to impart moisture resistance. They are also used in the application of molten wax due to their ability of easy handling, application and ability to formulate with other aqueous-based ingredients. Wax emulsions are more particularly used in paper and packaging coatings, wood finishes, printing inks, floor care products, etc.
Comparison of Silicone Emulsions and Wax Emulsions
Both silicone emulsions and wax emulsions have clear strengths in terms of surface performance. However, they excel in different areas. Below stated are some of aspects where both the additives work differently:
- Friction and Slip: Both silicone and wax emulsions tend to reduce the coefficient of friction on coated surfaces. However, silicone emulsions can achieve lower friction levels with smaller amounts of addition. For example, addition of just 0.3% of silicone emulsions can yield the lowest coefficient of friction outperforming polythene wax emulsions.
- Abrasion and Scratch Resistance: Wax emulsions can correlate more positively in terms of particle size distribution by providing rub resistance, soft feel and anti-blocking performance where bigger particle size leads to better performance of the application. On the other hand, silicone emulsions provide abrasion resistance at comparatively lower concentrations making them ideal for high-performance applications.
- Water Repellency: Silicone emulsions are more advantageous in terms of water repellency. Waxes are such additives that can significantly influence the surface properties of any coating by improving their water repellency and protecting its appearance. However, silicone emulsions possess hydrophobicity and have an ability to form a durable hydrophobic film on drying which gives it an edge to sustain water resistance over time.
- Gloss: Wax emulsions with very fine particles have a minimal effect on gloss making them an ideal choice for high-gloss formulations. Silicone emulsions are also gloss-friendly at low addition levels but they should be chosen carefully to avoid any surface defects at higher concentrations.
- Compatibility and Ease of Use: Wax emulsions are easy to incorporate making them a suitable choice for inks, coatings, and graphic arts. They are also a straightforward choice for formulators working with standard coating systems. On the other hand, silicone emulsions are easy to use but require careful dosage control to avoid issues like over-addition which can cause intercoat adhesion problems.
How to Choose the Correct Option
It is important to know the purpose of one’s coating while selecting between silicone emulsions and wax emulsions.
- Silicone Emulsions: Silicone emulsions should be used if one needs maximum slip and lubricity at low addition levels. They are considered a suitable choice for wood coating, industrial paints or specialty inks.
- Wax Emulsions: Wax emulsions should be used if one need a cost-effective easy-to-incorporate surface conditioner, etc. It is a go-to choice for applications where sustainability is a priority.
Take Away
This is a brief explanation about silicone emulsions, wax emulsions, their benefits and applications, the key difference between them and how to choose the correct option. We hope this information will be effective for you. Please let us know through your valuable feedback and the suggestion in the drop box.