As known we have presented some additives which are required for coatings sector with their spesific properties regarding to high quality products in our recent articles. One of these additives is micronized wax, which has small particle size in powder, dispersion or emulsion form.
Waxes are obtained from natural sources such as animals, plants, petroleum products and also synthetically.
Natural waxes come from the animals beeswax, spermaceti and as plants Carnauba wax, from the leaves of the Brazilian palm tree. Waxes are chemically synthesized by polymerization of ester, alcohol and carboxylic acid or their mixtures.
Wax polymers produced synthetically for various purposes and Fischer-Tropsch, polyethylene, polypropylene, polytetrafluoroethylene (PTFE) and polyamide, etc based types are used for coatings in order to get scratch resistance, rub resistance, mar resistance, water repellency, silky hand feel or soft touch effect, matting, texture effect.
Micro Powders Inc. (MPI) V has been developing and manufacturing innovative specialty micronized waxes, wax dispersions and emulsions since 1971.
Micronization, not to be confused with the term micro crystalline, describes the process in which large pieces of material, generally in the size range of 0.1 cm to 1.0 cm, are reduced in size to 1 to 100 microns depending on end use requirements.
Lots of methods have their own specialized equipment and advantages but the air jet process is the most widely used.
There are two wax mechanisms; one of them is mobilized wax particles in coating coming to the surface, the other one is blooming effect with a wax film forming on the coating surface.
Micropowders wax types are used for the applications such as; architectural coatings, industrial coatings, powder coatings, printing inks, wood coatings. Let us have a look to Micropowders’ wax types and technical specialties in detailed.
Natural Waxes
Natural Waxes generally refers to Carnauba, beeswax, spermacetti wax, and other like compounds. Carnauba is the only one of this group that can be easily micronized.
Microcrystalline
Derived from the residual still bottoms during the oil refining process. Not well suited for micronization.
Synthetic (Fischer-Tropsch)
Derived from the oxidation of coal to form carbon monoxide. Hydrogenated in the presence of an iron / nickel catalyst. Forms fully saturated hydrocarbon chains (50–100 carbons). It provides economical slip (<COF) and scratch resistance. MP®-12, MP®-22, MP®-22VF; XF; XXF are some of them.
Polyethylene (PE)
Polyethylene waxes come from the huge family of petroleum derived products known as Polyolefins. These polymers are produced by transition metal catalysis, normally at low pressure in the gas phase, in solution or in a slurry.
High Density Polyethylene (HDPE), Linear Low-Density Polyethylene (LLDPE) and Very Low-Density Polyethylene (VLDPE) are members of this family.
Low pressure polyethylenes are commercially available in the density range of 0.88 to 0.963 g/cc.[ ] Higher melting point, increase solvent resistance, maximum rub, abrasion and mar resistance. XF grades give excellent transparency and gloss retention. MPP®-230F; VF, PP®-620F; VF; XF; XXF; MPP®-123 are some of them.
Polypropylene (PP)
Polypropylene waxes are low density, high molecular weight and high melt point. Three key MPI grades of PP are; PropylMatte® 31, Micropro®, MicrolMatte®.PropylMatte® 31 is 100% polypropylene which provides consistent matting and gloss control.
Extreme toughness, good heat resistance, excellent anti- blocking, Improved burnishing and scuff resistance. Micropro®&MicroMatte® are modified polypropylene. It provides consistent gloss control, abrasion resistance, burnishing resistance, excellent surface “feel”, good heat resistance.
Higher melt point; extreme “toughness”, Improved scratch and “burnishing” resistance, excellent anti-blocking properties, some of them are Micropro 200, Micropro® 440W, PropylMatte® 31, MicroMatte® 1213 UVW.
Polytetrafluoroethylene (PTFE)
Made from recycled tape and extrusion products of PTFE, or directly from polymerized tetrafluoroethylene. PTFE is usually irradiated to reduce its molecular weight so that it may be micronized.
Once micronized, it becomes a very effective “wax” but its density of 2.2 g/cc and high cost have limited its use to all but the most high performance coatings. Some of PTFE waxes are called as Fluo® HT, Fluo® HTI-2, Fluo® 300; XF, Fluo® 625F-H, Fluo® 750TX Etc.
There are also blends of PTFE&Synthetic waxes which are Synfluo ® series. These are more economical than 100% PTFE wax. Their improved wax “mobility” provides excellent gloss retention, excellent lubricity (<COF) properties and scratch resistance as well. Synfluo® 170VF, Synfluo® 172VF; XF; Synfluo® 178VF; XF are some of the series which have different particle sizes.
Polyfluo® waxes (PE/PTFE) are melt-blends of polyethylene&PTFE in varying ratios and particle sizes. These waxes have rub and mar resistance of the PE and heat resistance and lubricity of the PTFE.
Also, they improved stability (no settling) and lower cost than 100% PTFE. Some of them are Polyfluo® 150, Polyfluo® 190, Polyfluo® 400XF. Polysilk® waxes are combinations of PE&PTFE&Amide. They provide slip and silky hand feel, improved scratch, rub and heat resistance.
Amides (EBS)
Amides describes the group of metal stearates and bisstearamides used as wax lubricants in coatings applications. Zinc stearate is the stearate metal complex of zinc and is often used as a sanding aid. Micromide® waxes are 100% Amide (EBS) or a combination wax with PTFE.
They offer excellent surface slip (<COF), scratch resistance and transparency. Superslip® waxes (PE/Amide) are combinations of polyethylene (PE) and bisstearamide (EBS) waxes. They provide lubricity (<COF) without the use of PTFE.
They offer excellent surface smoothness and “hand feel”, burnish resistance in low gloss systems. Micromide 520; XF, Superslip® 6515XF; Superslip® 6520; SuperGlide® 904; XF are some of them.
Aquawaxes (Oxidized); designed for water-based systems. Oxidation increases wax polarity, improved in-can stability. Some of them are Aquawax® 214VF,AquaPoly® 215VF, AquaPolyfluo 411, AquaPolysilk® 19’ Etc. Microspersion® dispersions are unique aqueous wax dispersions available with or without binder.Microspersion® 22-
50, Microspersion® 190-50, Microspersion ® 411-50, Microspersion® 31HD-40 are very successful types. Texture additives; unique texturizing agents with carefully controlled particle sizes for consistent texture effect. PropylTex® (polypropylene), AquaTex® (oxidized PE), NyloTex® (Nylon 6) are very successful.
Boysan Boya San. ve Tic. A.Ş. is glad to serve to the market with Micro Powders, Inc. products in Turkey and Turkic Republics with own 49-year-old technical and commercial experience.
Tuğba Sadıç
Technical Manager
Boysan A.Ş.
