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New metallic effect pigments for powder coatings
FOCUS areas of industrial finishing, and the major producers are active in promoting their product range. Jotun has introduced Reveal Smooth, a range of semi-matte powders for MDF applications (p3). DuPont announces a contract for its Alesta powders to coat facade and interior decorative items in a 54 floor luxury apartment block in Warsaw, Poland (p4). Interpon has created a new website for its powder coatings range and details of past projects are included (p4). Tiger Drylac has introduced its new range of “Natives and Aliens” powder coating to the North American market (p4). It includes 15 new colours and 20 special effect finishes. It is evident that these companies are fully aware of the important role that powder coatings will play in the future growth areas for industrial coatings. In the new era the customer’s choice of coating will be largely dictated by the cost savings in energy and labour of a one-coat finish, complete freedom from VOC and waste disposal commitments, and the profound effect of almost 100% utilization of the coating on material costs. The problems associated with high energy costs and escalating raw material prices are not going away in the foreseeable future! So where are the growth areas? We must discount any positive expansion in Europe while the Euro currency problems continue to task the ingenuity of both politicians and investors. China is now coming to realise that excess industrial growth rates are invariably accompanied by corresponding increases in labour costs, and its current rate of growth will soon become necessary just to satisfy internal demands. It always happens, but we never learn or provide for the time when export growth becomes static. There is much speculation that frustrated investors, who are currently sitting on most of the pile of global wealth, are turning their attention to the prospect of rich pickings from the Indian market. As a failed joint venture investor in 2
ON
POWDER
India during the early 1990s, I must caution them against the risks of excessive investment in a country sadly lacking in the basic infrastructure that is so essential to sustaining industrial growth. Sid Harris
TECHNICAL
C O AT I N G S stainless steel or RAL 1035, which finds many applications in appliances, shelving and facade components. Paper entitled “Pure and Chemical Resistant Copper, Gold and Champagne Colours for Powder coatings” by Dr P Winkelmann of Eckart GmbH, Germany, presented at the American Coatings Conference, held in Indianapolis on 7-9 May 2012. Copies of the Conference papers in CD format are available from the joint organizers, the Vincentz Network
New metallic effect pigments for powder coatings
Particle functionalization in coatings
A paper presented at the recent American Coatings Conference by Eckart, the German producer of metallic effect pigments, describes its latest efforts in the design of resistant metallic effect pigments for use in high and super durable powder coatings. The large surface area of aluminium flake pigments makes them more prone to oxidation in the presence of water and the metal will also dissolve in acids and bases due to its amphoteric behaviour. To overcome these corrosive influences, Eckart has applied silica to aluminium flake pigments where they link with the hydroxyl groups present on the metal surface. This treatment gives acceptable stability against acids but the silica barrier can be dissolved under basic conditions. Additional barrier protection of the silica treated metal surface can be provided by single or multiple polymer encapsulations. Commercially available aluminium pigments are already established for high performance powder coatings. Unfortunately silica does not combine with brass and copper pigments, and Eckart has developed a process for applying a double coated silica/polymer layer to these metallic pigments giving excellent appearance and chemical resistant qualities. These pigments give better hiding power for metallic effect golden and copper shades than mica pigments. The paper also features a new metallic pigment for producing a resistant champagne colour, a popular finish to simulate
The dispersion of inorganic pigments and extenders in coatings is facilitated by pre-treatment of the inorganic particles with organic components. This treatment has been shown to improve wetting of the particle surface as the first stage in the dispersion process. After dispersion the pigment particles are stabilized as the surface treatment promotes an interaction between the particle surface and the binder. Polyalcohols and polyamines are most commonly used for these surface treatments, and they are adsorbed onto the particle surface by relatively weak hydrogen bonding. These organic materials form dipole-dipole bonds and are frequently soluble in the binder system. It has been shown that this type of surface modification of the extenders, silica and wollastonite, reduces fading in polyester based powder coatings. A paper presented at the recent American Coatings Conference by Drs Fritzen and Rohe of Sachtleben Chemie introduces another method for improvement of wetting and binder bonding of inorganic particles by the use of alkoxysilane wetting agents. These have a different chemical structure with the molecule possessing a pigment-attracting head, which is adsorbed onto the pigment particle, and a bindercompatible tail. The pigmentseeking head of the surfactant forms a stronger covalent bond with the inorganic particle, particularly metal oxides such as JULY 2012
ON
POWDER
India during the early 1990s, I must caution them against the risks of excessive investment in a country sadly lacking in the basic infrastructure that is so essential to sustaining industrial growth. Sid Harris
TECHNICAL
C O AT I N G S stainless steel or RAL 1035, which finds many applications in appliances, shelving and facade components. Paper entitled “Pure and Chemical Resistant Copper, Gold and Champagne Colours for Powder coatings” by Dr P Winkelmann of Eckart GmbH, Germany, presented at the American Coatings Conference, held in Indianapolis on 7-9 May 2012. Copies of the Conference papers in CD format are available from the joint organizers, the Vincentz Network
New metallic effect pigments for powder coatings
Particle functionalization in coatings
A paper presented at the recent American Coatings Conference by Eckart, the German producer of metallic effect pigments, describes its latest efforts in the design of resistant metallic effect pigments for use in high and super durable powder coatings. The large surface area of aluminium flake pigments makes them more prone to oxidation in the presence of water and the metal will also dissolve in acids and bases due to its amphoteric behaviour. To overcome these corrosive influences, Eckart has applied silica to aluminium flake pigments where they link with the hydroxyl groups present on the metal surface. This treatment gives acceptable stability against acids but the silica barrier can be dissolved under basic conditions. Additional barrier protection of the silica treated metal surface can be provided by single or multiple polymer encapsulations. Commercially available aluminium pigments are already established for high performance powder coatings. Unfortunately silica does not combine with brass and copper pigments, and Eckart has developed a process for applying a double coated silica/polymer layer to these metallic pigments giving excellent appearance and chemical resistant qualities. These pigments give better hiding power for metallic effect golden and copper shades than mica pigments. The paper also features a new metallic pigment for producing a resistant champagne colour, a popular finish to simulate
The dispersion of inorganic pigments and extenders in coatings is facilitated by pre-treatment of the inorganic particles with organic components. This treatment has been shown to improve wetting of the particle surface as the first stage in the dispersion process. After dispersion the pigment particles are stabilized as the surface treatment promotes an interaction between the particle surface and the binder. Polyalcohols and polyamines are most commonly used for these surface treatments, and they are adsorbed onto the particle surface by relatively weak hydrogen bonding. These organic materials form dipole-dipole bonds and are frequently soluble in the binder system. It has been shown that this type of surface modification of the extenders, silica and wollastonite, reduces fading in polyester based powder coatings. A paper presented at the recent American Coatings Conference by Drs Fritzen and Rohe of Sachtleben Chemie introduces another method for improvement of wetting and binder bonding of inorganic particles by the use of alkoxysilane wetting agents. These have a different chemical structure with the molecule possessing a pigment-attracting head, which is adsorbed onto the pigment particle, and a bindercompatible tail. The pigmentseeking head of the surfactant forms a stronger covalent bond with the inorganic particle, particularly metal oxides such as JULY 2012