Whether looking for a brilliant metallic sparkle, the smooth luster of solid metal or the functional attributes of a high opacity pigment, Silberline has the product for you. Additional help in recommending the best product is also readily available from our technical service and product applications team. Contact information for our technical support team can be found on the back cover of this guide. Below is a brief list outlining a few basics designed to help with the selection of the most appropriate pigment for your particular application. This technology providesaluminium pigment in a low-dusting, low-VOC pellet or granule for a varietyof polymers.
When incorporated into polymers in a silver masstone, these pigments can achieve a metallic colour similar to brushed steel or anodised aluminium. All of these grades can be combined with transparent pigments and dyes to produce extraordinarily clean, bright metallic colours. They can also be incorporated into polymers at a very low addition level typically 0.
In uncoloured polymers, SILVET LR gives very bright silver metallic effects, and in coloured polymer, cost effective superior performance alternatives to pearlescent effects are achieved. Tirso Martins, , Cj. All Rights Reserved. Individual product information and material safety data sheets are available fromSilberline upon request and must be referred to because of potential serious hazards associated with the use of these products.
This pre-mix is then passed through the extrusion, kibbling and milling stages of production to yield a metallic-effect powder coating with excellent over spray recyclability and suitability for tribo as well as corona application. However, pigment damage during extrusion is difficult to completely eliminate, therefore this approach is generally used for sparkle or hammer-finish metallic powder coatings.
Dry blending process - The metallic pigment is generally supplied in the form of a free-flowing powder where the metallic particles are completely encapsulated by a uniform and coherent silica matrix. The dry blending process involves gentle tumble blending of the finished powder coating resin with the surface-treated metallic pigment in a double cone blender. This type of process provides a metallic-effect powder coating with excellent chemical and humidity resistance often suitable for one-coat application. The type of metallic pigment available allows the formulation of metallic effects approaching some more traditional wet coating effects.
Bonding process - The metallic pigment is physically attached or bonded to the finished powder coating particles through a combination of mechanical action and heat.
High-Solids Solventborne Coatings
This approach provides a metallic-effect powder coating with superior recovery of over spray, however, the mechanical action does result in some pigment damage that can reduce the intensity of the metallic effect as well as reducing chemical stability performance. A number of surface-treated metallic pigments are available for powder coatings, particularly for addition via either the dry blending or bonding processes. Surface treatment by silica matrix provides excellent compatibility with most powder coating resin chemistries, while a polymer encapsulation is also available providing a metallic pigment with good compatibility, particularly with acrylic powder coatings.
Each of these surface treatments improves the spray efficiency of the metallic-effect powder coating whether by electrostatic or tribo application methods. The surface treatments have also been shown to improve bonding efficiency when added via the bonding process. The other major advantage of the surface treatment is the excellent chemical and humidity stability of the final powder coating due to improved pigment stability, particularly when added by dry blending.
Metallic Effects in Radiation-Cure Coatings Metallic pigments without surface treatment are in use in two-pack radiation-cure coatings where the pigment is isolated to prevent reaction with the monomer used in the coating. More recently, surface-treated metallic pigments have been developed that allow excellent one-pack stability.
The surface treatment is generally a modification of silica encapsulation of the metallic pigment, and the resulting product is usually supplied in the form of a low- or zero-VOC pigment or paste exhibiting excellent compatibility with radiation-cure coatings. The high light reflectivity of metallic pigments results in almost no adverse effects on the curing or speed of curing of the formulated coating.
Conclusion Metallic pigments have continued to develop at a pace that allows their use in an ever-wider range of coating applications and meeting designer's desire for added value, product differentiation and consumer appeal. The emergence of compliant coatings to meet ever more demanding environmental considerations while maintaining excellent performance requirements has challenged metallic pigment manufacturers to provide pigments tailored for use in those compliant coatings.
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Metallic pigment manufacturers have risen to that challenge through advanced pigment technologies and surface treatments that are meeting those demands. Metallic pigments and metallic effects will continue to evolve to meet present and future market requirements. For further information, visit www. Silberline Ltd. Report Abusive Comment Thank you for helping us to improve our forums. Is this comment offensive? Please tell us why. This website requires certain cookies to work and uses other cookies to help you have the best experience.
Such a compound is known as a crosslinker for it produces, on reaction with the resin, a three-dimensional structure similar to the polyurethane formed from a polyol and an isocyanate. When these two components are mixed together, a chemical reaction takes place between the hydroxyl groups on the polymer acrylic resin and the isocyanate groups on the cross linker:. This reaction proceeds relatively slowly at room temperature, allowing enough time for the paint to be applied, after which the solvent thinner evaporates and the painted item is placed in an oven to accelerate the chemical reaction.
This greatly increases the molecular mass of the polymer causing it to become a three-dimensional molecule and form a hard film, resistant to chemicals. Decorative gloss paints typically contain alkyd polymers resins. A typical resin is that produced from a polyol such as propane-1,2,3-triol glycerol with a dibasic acid such as benzene-1,2-dicarboxylic phthalic anhydride and a drying oil linseed or soybean oil.
Dispersants: K-SPERSE & DISPARLON | King Industries, Inc.
On being heated together, ester linkages are formed, and water is a by-product. The name alkyd is derived from alcohol and anhydride. The first step in making the alkyd polymer is the reaction between the triol and the drying oil to produce a monoglyceride. For example:. The alkyd resins, which generally have relative molecular masses in the range of 10 - 50 , are usually carried in organic solvents solvent-borne paints.
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Turpentine extracted from trees was used in the past as the solvent, but this has been replaced by solvents from petrochemical feedstock, such as 'white spirit' which is a mixture of aliphatic and alicyclic hydrocarbons. Once the alkyd resin is applied, the pendant oil drying groups react with oxygen in the air to form a cross-linked, hard thermoset coating, with a high molecular mass.
Epoxy resins are often used as the binder in industrial coatings primers. They give the paint excellent adhesion together with high resistance to chemicals corrosion , and physical resistance necessary, for example, on ships and chemical storage tanks.
The epoxy resins are made from 1-chloro-2,3-epoxypropane produced from 3-chloropropene and substituted phenols, such as bisphenol A :. The value of n can be controlled to give a range of resins varying from viscous liquids to solids with high melting points. Epoxy resins can be carried in solvents such as aromatic hydrocarbons, alcohols, ketones and esters solvent-borne paints or as dispersions in water water-borne paints as true emulsions. They are not normally used in topcoats for outdoors because they are susceptible to UV degradation, but they make excellent interior coatings and exterior primers.
Pigments give colour and opacity to paints. Amongst the organic pigments, particularly important are azo- , phthalocyanine and anthraquinone derivatives. It has a high refractive index and gives a 'gloss' to the paint. Another widely used inorganic pigment is finely divided calcium carbonate.
This has a low refractive index and is used, together with titanium dioxide, to produce 'matt' paints. Other pigments include iron oxides black, yellow and red , zinc oxide and carbon black. Powdered metals such as zinc and some metal compounds, for example zinc phosphate, have corrosion inhibiting properties. As the paint dries, a film is formed which adheres to the surface of the material to which it is being applied.
Emulsion paints dry by a physical process involving the evaporation of water followed by coalescence of the polymer droplets and their subsequent integration into a hard polymer matrix that acts as a binder for the pigment. On applying gloss paints, the alkyd polymer cross-links by an oxidation reaction with oxygen in the air once the solvent has largely evaporated. This reaction is accelerated using salts of transition metals for example, cobalt and manganese naphthenates.
The transition metal ion with variable oxidation state catalyses cross linking of the polymer chains, producing a hard surface film to the paint.
Effect of some selected pigments on the properties of styrene butadiene rubber
These vary greatly according to the particular end use. The requirements for an automotive topcoat, for example, will be very different to those for a decorative ceiling paint.
Numerous methods are used including: brush, roller, dipping, flowcoating, spraying, hot spraying, electrostatic spraying, airless spraying, electrodeposition, powder coating, vacuum impregnation and immersion. Lead compounds are no longer used in decorative paints and automotive paints.
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The quantity of lead compounds still being used in specialised industrial paints has been greatly reduced and eventually alternatives will be found. This also applies to chromates which, although they perform well and in the past have been extensively used on motor vehicles, are very toxic.