Waxes are a useful formulation tool which can enable the developer to alter many performance improving functions of an coating or ink’s surface to meet the requirements of their usings. Wax additives are used extensively due to their flexibility of use and significant positive impact on many formulation types.
Slip or lower coefficient of friction
Rub and abrasion resistance
Blocking or anti-blocking
Tianshiwax offers a broad line of specialty micronized powders, dispersions, emulsions and other specialty wax additives
Polyethylene wax – a hard synthetic wax used for slip, scratch and abrasion resistance. Oxidised grades may be easily incorporated.
Polypropylene wax – a hard wax useful for abrasion resistance and matting. The only wax which will not increase slip property and may impart a textured or rubbery feel.
Fischer-Tropsch wax – a hard wax used for scratch resistance, slip and anti-blocking.
Amide wax – used for slip, anti-blocking and very sandable. A wide range of melting points to suit processing or drying conditions.
Paraffin wax – the wax of choice when hydrophobicity is required. May also be recommended for slip and release properties.
Carnauba wax – the hardest natural wax. Used for slip, anti-blocking and scratch resistance.
PTFE powder– chemically resistant and recommended for high degrees of slip.
Formulation and mechanisms of waxes in coatings
A micronized wax’s efficiency is partly governed by its particle size which must be in the formulator’s thoughts when factoring the coating’s dry film thickness . Too small a particle in relation to the film weight will result in too little protection; and too large a particle will result in the wax being more easily removed from the binder when abraded and therefore in the long run offering little protection. A “just right” scenario where 25% to 33% of the wax protrudes from the dry film surface should offer adequate protection to the coating as well as to impart other properties which may be desired. This emergence of the particles from the coating layer is called the “Ball-Bearing Effect”. As well as offering physical improvements to the coating, this effect may also give rise to matting of the coating due to protruding particles scattering light reflected from the surface.
When thinking about particle size it is also important to note that this may have an effect on the surface properties within the working limits of the particle size. For example, a smaller particle will have less of an effect on gloss and as particle size increases, an improvement in slip and anti-blocking may be seen.
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