- Email: [email protected]
Powder Coating and Films
FOCUS QECC is a joint venture established by Evonik, DEG and Jiaozhou Finance Investment Center (JFIC) in 1994 based in Qingdao (Shandong Province), China. It has production capacity of approximately 75 thousand metric tons of Carbon Black per annum. The plant is equipped with three production lines and its main manufacturing focus is on high-end Carbon Black products. Through its proximity to key customers, connection to one of China's largest ports and modern transportation infrastructure, the Qingdao facility is an excellent logistics base for participation in future market growth. Orion will initially step into the established joint venture in place of Evonik and DEG, but OEC and JFIC are in advanced talks regarding the transfer of JFIC shares to Orion in accordance with regulations governing Chinese state-owned enterprises. "We are pleased with the progress made on bringing this facility back into our global carbon black manufacturing network,'' said Jack Clem, CEO of Orion. "We believe that this acquisition will greatly improve our ability to serve the highly important Chinese market, as well as the rest of Asia-Pacific, over and above the current use of our global network for exports to that region.'' The agreement is subject to Chinese government review and other customary closing conditions and is expected to close in the fourth quarter of 2015. The European Commission approved Orion's prospective acquisition of QECC concurrent with its consideration of the sale of Evonik's Carbon Black business to Rh"ne Capital and Triton Advisors in 2011. Until the closing, Orion and QECC will continue to operate independently.
Original Source: European Coatings Journal, 19 October 2015 (website: http://www. european-coatings.com/) Copyright dmg events (MEA) Ltd 2015
TECHNOLOGY Preparation of Modified Nano ZnO/ Polyester/TGIC Powder Coating Nanocomposite and Evaluation of its Antibacterial Activity Powder coating nanocomposite with antibacterial properties is the aim of this study. For this purpose, nano zinc oxide was modified by vinyltrimethoxysilane (VTMS) and Triethoxy(methyl)silane (TEMS). Then various percentages of modified and nonmodified nano ZnO (1, 3 and 5%), polyester resin and triglycidyl isocyanurate as a hardener were blended by twin screw extruder. Prepared polymer–matrix composite (PMC) was atomized and coated by electrostatic method on aluminum plates. Finally, samples were cured for 10 min at 200 8C. For investigating the thermal stabilities of modified nano particles,
December 2015
ON
POWDER
thermogravimetric analyses (TGA) were used. Antibacterial properties of coatings were investigated by gram negative bacteria Escherichia coli and gram positive Staphylococcus aureus. The results showed that the coatings demonstrate significant antibacterial activity by increasing amounts of ZnO nanoparticles (5%) when were modified by VTMS. Surface of nano ZnO was successfully modified with TEMS and VTMS. FTIR spectra confirmed this modification. TGA results showed that the thermal stability of modified nano ZnO with VTMS is more compatible in blending process than TEMS. Also the SEM images represented a good dispersion of modified nano particle in polymeric matrix and the best dispersion was for VTMS. The antibacterial experiments showed that the efficiency of coatings containing modified nano ZnO is more than unmodified ones. The maximum antibacterial against both E. coli and S. aureus were 99 and 99.5% for VTMS-ZnO, respectively.
Original Source: Composites Part B: Engineering, Volume 82, 1 December 2015, Pages 190–195 Found on ScienceDirect (website: www.sciencedirect.com) Copyright 2015 Elsevier Ltd
Improving Adhesion of Powder Coating on PEEK Composite: Influence of Atmospheric Plasma In aeronautic industries, powder coatings are increasingly used because of environmental considerations. During the deposition of such a coating on a substrate piece, the main objective is to obtain a good coating/ substrate adhesion. In this study, the targeted substrate is a Poly-(Ether EtherKetone)-(PEEK) based composite material. Due to the poor surface energy of PEEK, a surface treatment is necessary in order to enhance its adhesion with the coating. In this purpose, atmospheric plasma treatment has been chosen and the influence of plasma parameters has been studied. Four scan speed nozzles and three gases (Air, N2 and Argon) plasma has been tested. The increase of adhesion with increasing wettability, polarity and nanoroughness has been evidenced. A particular study of the type of grafted polar functionalities according to gas nature allowed to better understand the plasma mechanism and the cross-impact of polarity and nanoroughness in adhesion enhancement. This work highlights the influence of plasma parameters on PEEK composite treated surface, which leads both on roughness modifications at nano-scale and chemical functionalization. Firstly, the influence of increasing exposure time on adhesion enhancement has been evidenced. The obtained increase of wettability is directly linked with increase of surface polarity and nanoroughness. Secondly, this study shows the most important influence of the gas nature. Indeed, we see that the nature of grafted polar functions on substrate surface depends on
C OAT I N G S the gas used. In this case, it is possible to have a less rough surface but still more favorable to adhesion because of a more efficient created bond strength. The better impact of grafted single bond C–O and grafted nitrogen functions have been evidenced. In the case of nitrogen plasma treatment, the functionalization by imine groups seems to be more convenient. Moreover this study demonstrates the interest of considering both plasma (Air, N2, Argon) and atmospheric gases species in the case of an atmospheric plasma treatment. As a conclusion, we evidenced that nitrogen and air plasma treatment notably increase adhesion of epoxy powder coating on PEEK based composites. Using air as gas treatment is very convenient for industrial applications because it considerably reduces manufacturing costs by the ease of implementation.
Original Source: Applied Surface Science, 1 December 2015, Volume 357, Part A, Pages 1196–1204. Found on Science Direct (website: www.sciencedirect.com) Copyright 2015 Elsevier Ltd
New Pigment Achieves Dark-Blue Styling Depth Effect German Merck Group launched the new special effect pigment Tigris Blue as part of the Xirallic NXT range. The name is based on white tigers and their blue eyes. The blue pigment is the third product in the Xirallic NXT range, which also includes Panthera Silver and Leonis Gold. The pigment developed by Mercks Global Marketing Coatings, Pigments & Functional Materials Division catches the light and provides an impressive depth to the dark blue styling as well as elegant black designs. The special effect pigment gives an innovative, threedimensional elegance to black and dark blue automotive coatings. The pigment is also suitable for plastic coatings, industrial coatings and powder coatings. The pigment can be applied externally and internally and may be combined with other colour and special effect pigments.
Original Source: Farbe und Lack (Online Version), 22 Sep 2015, (website: http://www. farbeundlack.de/) (in German) Copyright Vincentz Network 2015
Powder Coating and Films This chapter reviews powder coating both spray application and bulk application. As each technique is discussed, advantages and disadvantages are covered. Direct application of films to substrate by lamination and adhesive bonding is included. Spray powder process included corona charging, tribocharging, and hot flocking. Thick and thin films are considered and some special issues with thick film coatings are discussed. Bulk coating is primarily fluidized bed coating. Special
5
FOCUS formulation practices of powder coatings are presented along with lists of commercial powder fluorocoating products. Film lamination of fluoropolymer films is included in this edition. Included is fluoropolymer film production by three processes: melt extrusion, paste extrusion, and skiving. Since films for laminating are often surface treated to improve adhesion, this subject is reviewed. Included are sodium etch, plasma, flame, and corona treatments. Films are adhered to substrates by heat bonding and adhesive laminating. Finally, commercial fluoropolymer films are listed.
Original Source: Fluorinated Coatings and Finishes Handbook (Second Edition): The Definitive User’s Guide, A volume in Plastics Design Library 2016, Pages 185–209. Found on ScienceDirect (website: www.sciencedirect. com) Copyright 2015 Elsevier Ltd
BYK Ceraflour 964 - a New ProcessOptimized Wax Additive In response to the demands of costoptimized application processes, BYK has launched a new wax additive with a particularly low melting point, the Ceraflour 964. With excellent degassing features, this new product is effective in baking and extruding, especially in low-temperature and beta-HAA systems. Furthermore, it does not affect gloss and surface tension nor form a wax film on the surface. Even when used in clear coatings, it assures retention of transparency.
Original Source: PPCJ, Polymers, Paint, Colour Journal, Sep 2015, 205 (4612), 4 (website: http://www.polymerspaintcolourjournal.com/) Copyright dmg events (MEA) Ltd 2015
Sun Chemical Launches its Series of Pearlescent Pigments for Exterior Coatings Sun Chemical Performance Pigments has launched its new SunMica Exterior XC product line, a series of 13 pearlescent special effect pigments specifically geared for exterior coatings applications, especially powder coatings. Available in all major colors, including six particle size distributions of pearlescent white, SunMica Exterior XC consists of thin natural mineral mica flakes coated with optical layers of titanium dioxide and/or iron dioxide that have been specially treated to have exceptional outdoor durability. SunMICA Exterior XC pigments add depth, shimmer and sparkle, providing unlimited styling possibilities. The Exterior XC line offers excellent weather stability, outstanding lightfastness, humidity resistance, batch-to-batch color consistency, and superior intercoat adhesion in most coating applications. Geared toward the automotive, auto custom finishes and accessories, architectural, lawn & garden equipment and outdoor furniture markets,
6
ON
POWDER
SunMica Exterior XC pigments are compatible with both solvent and waterborne coatings, powder and coil coatings, 2K isocyanates, alkyds, epoxy, UV curables and stuccos. SunMica Exterior XC joins Sun Chemical's large family of effect pigments, including the Benda-Lutz family of metallic pigments. Sun Chemical's SunMica XC special effect pigments were on display at ABRAFATI 2015 in Sao Paulo, Brazil on 1315 Oct 2015.
Original Source: Sun Chemical, 6 Oct 2015. Found on SpecialChem Coatings and Inks Formulation, (website: http://www. specialchem4coatings.com) Copyright Sun Chemical 2015
New Surfaces Delay Ice Formation If you've ever waited on an airport runway for your plane to be de-iced, had to remove all your food so the freezer could defrost, or arrived late to work because you had to scrape the sheet of ice off your car windshield, you know that ice can cause major headaches. "People intuitively know that frost can be bad,'' said Amy Betz, a professor in mechanical engineering at Kansas State University. Betz and her colleagues have created a surface that can significantly delay frost formation, even at temperatures of down to 6 degrees Celsius below freezing. The surface is biphilic, meaning it repels water in some areas and attracts it in others. Previous research by other groups has focused mainly on the frost-preventing properties of superhydrophobic surfaces. In general, the surfaces work by repelling water droplets before they have time to freeze. There is little research, however, on surfaces that mix hydrophobic and hydrophilic areas. Betz had experience working with such biphilic surfaces for boiling experiments - in 2012 she and her colleagues found that superhydrophilic surfaces with superhydrophobic hexaganol spots resulted in the most efficient transfer of heat during boiling, compared to surfaces with uniform wettability. She wondered how similar "split personality'' surfaces would affect ice formation. Betz, along with fellow Kansas State University mechanical engineering professor Melanie Derby, and students Alexander Van Dyke and Diane Collard, created three different biphilic surface patterns. Each surface consisted of hydrophilic circles on a hydrophobic background. For two of the surfaces, the circles were 200 micrometers across, and either arranged in an even grid, like the dots on the 4-side of dice, or staggered, like the dots on the 5-side of dice. The third surface consisted of smaller, 25 micrometer-sized circles in an even grid. The researchers also made a purely hydrophobic surface and a purely hydrophilic surface. The team then tested the surfaces by placing them in a chamber at a range of set temperatures and humidities and waiting for three hours to see if frost formed. Ice crystals appeared at the warmest temperatures for
C OAT I N G S the hydrophilic surface - at about 1-2 degrees Celsius below freezing. The hydrophobic surface decreased the temperature required for freezing in the three-hour time frame by about an additional 1 degree Celsius. But the biphilic surfaces had the most success. At 60 percent relative humidity, all three biphilic surfaces required temperatures around 6 degrees below freezing before ice would form in the threehour window. The researchers attribute the frost-busting properties to the unusual condensation and coalescence dynamics on the biphilic surfaces. Small droplets about 5 micrometers in diameter initially formed on both the hydrophobic and hydrophilic areas, Betz said, but as the droplets grew, they merged with other droplets, and became confined to the hydrophilic spots. Each time a droplet merged with another droplet it released energy held by surface tension, because the surface area of the new droplet was smaller than the combined surface area of the two droplets prior to merging. The new droplet was also larger, which increased the energy removal needed to freeze it. Both factors delayed the freezing of the droplets, the researchers said. The researchers made the surfaces from silicon wafers and a thin coating of a hydrophobic chemical commonly used in the semiconductor industry. The surfaces were strong enough to withstand hundreds of hours of testing over two years, but Betz said that more robust materials would likely be used for commercial applications of frost resistant surfaces. She said airplane wings are one obvious application, but there are many others, including in refrigerators, air conditioners, and air-cooled condensers in power plants.
Original Source: Applied Physics Letters, 6 October 2015, Volume 107, Issue 14, (website: www.aip.org) Copyright AIP Publishing LLC 2015
Overcoming Adhesion Failures of UV Coatings with Atmospheric Plasma Treatment UV curable coatings are becoming an increasingly popular alternative to conventional coatings. Compared with thermal coatings, UV coatings provide a number of benefits to plastic part manufacturers including enhanced appearance, improved performance, and various process worker safety, and environmental advantages. But, same high speed curing and highly-crosslinked chemistry that underlie these benefits can also make adhesion failures more likely. This paper examines the problem of adhesion common to UV curable liquid and powder coatings, and describes some tradeoffs associated with popular methods to reduce adhesion problems. Atmospheric plasma provides an especially attractive method of enhancing adhesion of UV cure coatings to a wide range of plastic materials.
December 2015
Original Source: European Coatings Journal, 19 October 2015 (website: http://www. european-coatings.com/) Copyright dmg events (MEA) Ltd 2015
TECHNOLOGY Preparation of Modified Nano ZnO/ Polyester/TGIC Powder Coating Nanocomposite and Evaluation of its Antibacterial Activity Powder coating nanocomposite with antibacterial properties is the aim of this study. For this purpose, nano zinc oxide was modified by vinyltrimethoxysilane (VTMS) and Triethoxy(methyl)silane (TEMS). Then various percentages of modified and nonmodified nano ZnO (1, 3 and 5%), polyester resin and triglycidyl isocyanurate as a hardener were blended by twin screw extruder. Prepared polymer–matrix composite (PMC) was atomized and coated by electrostatic method on aluminum plates. Finally, samples were cured for 10 min at 200 8C. For investigating the thermal stabilities of modified nano particles,
December 2015
ON
POWDER
thermogravimetric analyses (TGA) were used. Antibacterial properties of coatings were investigated by gram negative bacteria Escherichia coli and gram positive Staphylococcus aureus. The results showed that the coatings demonstrate significant antibacterial activity by increasing amounts of ZnO nanoparticles (5%) when were modified by VTMS. Surface of nano ZnO was successfully modified with TEMS and VTMS. FTIR spectra confirmed this modification. TGA results showed that the thermal stability of modified nano ZnO with VTMS is more compatible in blending process than TEMS. Also the SEM images represented a good dispersion of modified nano particle in polymeric matrix and the best dispersion was for VTMS. The antibacterial experiments showed that the efficiency of coatings containing modified nano ZnO is more than unmodified ones. The maximum antibacterial against both E. coli and S. aureus were 99 and 99.5% for VTMS-ZnO, respectively.
Original Source: Composites Part B: Engineering, Volume 82, 1 December 2015, Pages 190–195 Found on ScienceDirect (website: www.sciencedirect.com) Copyright 2015 Elsevier Ltd
Improving Adhesion of Powder Coating on PEEK Composite: Influence of Atmospheric Plasma In aeronautic industries, powder coatings are increasingly used because of environmental considerations. During the deposition of such a coating on a substrate piece, the main objective is to obtain a good coating/ substrate adhesion. In this study, the targeted substrate is a Poly-(Ether EtherKetone)-(PEEK) based composite material. Due to the poor surface energy of PEEK, a surface treatment is necessary in order to enhance its adhesion with the coating. In this purpose, atmospheric plasma treatment has been chosen and the influence of plasma parameters has been studied. Four scan speed nozzles and three gases (Air, N2 and Argon) plasma has been tested. The increase of adhesion with increasing wettability, polarity and nanoroughness has been evidenced. A particular study of the type of grafted polar functionalities according to gas nature allowed to better understand the plasma mechanism and the cross-impact of polarity and nanoroughness in adhesion enhancement. This work highlights the influence of plasma parameters on PEEK composite treated surface, which leads both on roughness modifications at nano-scale and chemical functionalization. Firstly, the influence of increasing exposure time on adhesion enhancement has been evidenced. The obtained increase of wettability is directly linked with increase of surface polarity and nanoroughness. Secondly, this study shows the most important influence of the gas nature. Indeed, we see that the nature of grafted polar functions on substrate surface depends on
C OAT I N G S the gas used. In this case, it is possible to have a less rough surface but still more favorable to adhesion because of a more efficient created bond strength. The better impact of grafted single bond C–O and grafted nitrogen functions have been evidenced. In the case of nitrogen plasma treatment, the functionalization by imine groups seems to be more convenient. Moreover this study demonstrates the interest of considering both plasma (Air, N2, Argon) and atmospheric gases species in the case of an atmospheric plasma treatment. As a conclusion, we evidenced that nitrogen and air plasma treatment notably increase adhesion of epoxy powder coating on PEEK based composites. Using air as gas treatment is very convenient for industrial applications because it considerably reduces manufacturing costs by the ease of implementation.
Original Source: Applied Surface Science, 1 December 2015, Volume 357, Part A, Pages 1196–1204. Found on Science Direct (website: www.sciencedirect.com) Copyright 2015 Elsevier Ltd
New Pigment Achieves Dark-Blue Styling Depth Effect German Merck Group launched the new special effect pigment Tigris Blue as part of the Xirallic NXT range. The name is based on white tigers and their blue eyes. The blue pigment is the third product in the Xirallic NXT range, which also includes Panthera Silver and Leonis Gold. The pigment developed by Mercks Global Marketing Coatings, Pigments & Functional Materials Division catches the light and provides an impressive depth to the dark blue styling as well as elegant black designs. The special effect pigment gives an innovative, threedimensional elegance to black and dark blue automotive coatings. The pigment is also suitable for plastic coatings, industrial coatings and powder coatings. The pigment can be applied externally and internally and may be combined with other colour and special effect pigments.
Original Source: Farbe und Lack (Online Version), 22 Sep 2015, (website: http://www. farbeundlack.de/) (in German) Copyright Vincentz Network 2015
Powder Coating and Films This chapter reviews powder coating both spray application and bulk application. As each technique is discussed, advantages and disadvantages are covered. Direct application of films to substrate by lamination and adhesive bonding is included. Spray powder process included corona charging, tribocharging, and hot flocking. Thick and thin films are considered and some special issues with thick film coatings are discussed. Bulk coating is primarily fluidized bed coating. Special
5
FOCUS formulation practices of powder coatings are presented along with lists of commercial powder fluorocoating products. Film lamination of fluoropolymer films is included in this edition. Included is fluoropolymer film production by three processes: melt extrusion, paste extrusion, and skiving. Since films for laminating are often surface treated to improve adhesion, this subject is reviewed. Included are sodium etch, plasma, flame, and corona treatments. Films are adhered to substrates by heat bonding and adhesive laminating. Finally, commercial fluoropolymer films are listed.
Original Source: Fluorinated Coatings and Finishes Handbook (Second Edition): The Definitive User’s Guide, A volume in Plastics Design Library 2016, Pages 185–209. Found on ScienceDirect (website: www.sciencedirect. com) Copyright 2015 Elsevier Ltd
BYK Ceraflour 964 - a New ProcessOptimized Wax Additive In response to the demands of costoptimized application processes, BYK has launched a new wax additive with a particularly low melting point, the Ceraflour 964. With excellent degassing features, this new product is effective in baking and extruding, especially in low-temperature and beta-HAA systems. Furthermore, it does not affect gloss and surface tension nor form a wax film on the surface. Even when used in clear coatings, it assures retention of transparency.
Original Source: PPCJ, Polymers, Paint, Colour Journal, Sep 2015, 205 (4612), 4 (website: http://www.polymerspaintcolourjournal.com/) Copyright dmg events (MEA) Ltd 2015
Sun Chemical Launches its Series of Pearlescent Pigments for Exterior Coatings Sun Chemical Performance Pigments has launched its new SunMica Exterior XC product line, a series of 13 pearlescent special effect pigments specifically geared for exterior coatings applications, especially powder coatings. Available in all major colors, including six particle size distributions of pearlescent white, SunMica Exterior XC consists of thin natural mineral mica flakes coated with optical layers of titanium dioxide and/or iron dioxide that have been specially treated to have exceptional outdoor durability. SunMICA Exterior XC pigments add depth, shimmer and sparkle, providing unlimited styling possibilities. The Exterior XC line offers excellent weather stability, outstanding lightfastness, humidity resistance, batch-to-batch color consistency, and superior intercoat adhesion in most coating applications. Geared toward the automotive, auto custom finishes and accessories, architectural, lawn & garden equipment and outdoor furniture markets,
6
ON
POWDER
SunMica Exterior XC pigments are compatible with both solvent and waterborne coatings, powder and coil coatings, 2K isocyanates, alkyds, epoxy, UV curables and stuccos. SunMica Exterior XC joins Sun Chemical's large family of effect pigments, including the Benda-Lutz family of metallic pigments. Sun Chemical's SunMica XC special effect pigments were on display at ABRAFATI 2015 in Sao Paulo, Brazil on 1315 Oct 2015.
Original Source: Sun Chemical, 6 Oct 2015. Found on SpecialChem Coatings and Inks Formulation, (website: http://www. specialchem4coatings.com) Copyright Sun Chemical 2015
New Surfaces Delay Ice Formation If you've ever waited on an airport runway for your plane to be de-iced, had to remove all your food so the freezer could defrost, or arrived late to work because you had to scrape the sheet of ice off your car windshield, you know that ice can cause major headaches. "People intuitively know that frost can be bad,'' said Amy Betz, a professor in mechanical engineering at Kansas State University. Betz and her colleagues have created a surface that can significantly delay frost formation, even at temperatures of down to 6 degrees Celsius below freezing. The surface is biphilic, meaning it repels water in some areas and attracts it in others. Previous research by other groups has focused mainly on the frost-preventing properties of superhydrophobic surfaces. In general, the surfaces work by repelling water droplets before they have time to freeze. There is little research, however, on surfaces that mix hydrophobic and hydrophilic areas. Betz had experience working with such biphilic surfaces for boiling experiments - in 2012 she and her colleagues found that superhydrophilic surfaces with superhydrophobic hexaganol spots resulted in the most efficient transfer of heat during boiling, compared to surfaces with uniform wettability. She wondered how similar "split personality'' surfaces would affect ice formation. Betz, along with fellow Kansas State University mechanical engineering professor Melanie Derby, and students Alexander Van Dyke and Diane Collard, created three different biphilic surface patterns. Each surface consisted of hydrophilic circles on a hydrophobic background. For two of the surfaces, the circles were 200 micrometers across, and either arranged in an even grid, like the dots on the 4-side of dice, or staggered, like the dots on the 5-side of dice. The third surface consisted of smaller, 25 micrometer-sized circles in an even grid. The researchers also made a purely hydrophobic surface and a purely hydrophilic surface. The team then tested the surfaces by placing them in a chamber at a range of set temperatures and humidities and waiting for three hours to see if frost formed. Ice crystals appeared at the warmest temperatures for
C OAT I N G S the hydrophilic surface - at about 1-2 degrees Celsius below freezing. The hydrophobic surface decreased the temperature required for freezing in the three-hour time frame by about an additional 1 degree Celsius. But the biphilic surfaces had the most success. At 60 percent relative humidity, all three biphilic surfaces required temperatures around 6 degrees below freezing before ice would form in the threehour window. The researchers attribute the frost-busting properties to the unusual condensation and coalescence dynamics on the biphilic surfaces. Small droplets about 5 micrometers in diameter initially formed on both the hydrophobic and hydrophilic areas, Betz said, but as the droplets grew, they merged with other droplets, and became confined to the hydrophilic spots. Each time a droplet merged with another droplet it released energy held by surface tension, because the surface area of the new droplet was smaller than the combined surface area of the two droplets prior to merging. The new droplet was also larger, which increased the energy removal needed to freeze it. Both factors delayed the freezing of the droplets, the researchers said. The researchers made the surfaces from silicon wafers and a thin coating of a hydrophobic chemical commonly used in the semiconductor industry. The surfaces were strong enough to withstand hundreds of hours of testing over two years, but Betz said that more robust materials would likely be used for commercial applications of frost resistant surfaces. She said airplane wings are one obvious application, but there are many others, including in refrigerators, air conditioners, and air-cooled condensers in power plants.
Original Source: Applied Physics Letters, 6 October 2015, Volume 107, Issue 14, (website: www.aip.org) Copyright AIP Publishing LLC 2015
Overcoming Adhesion Failures of UV Coatings with Atmospheric Plasma Treatment UV curable coatings are becoming an increasingly popular alternative to conventional coatings. Compared with thermal coatings, UV coatings provide a number of benefits to plastic part manufacturers including enhanced appearance, improved performance, and various process worker safety, and environmental advantages. But, same high speed curing and highly-crosslinked chemistry that underlie these benefits can also make adhesion failures more likely. This paper examines the problem of adhesion common to UV curable liquid and powder coatings, and describes some tradeoffs associated with popular methods to reduce adhesion problems. Atmospheric plasma provides an especially attractive method of enhancing adhesion of UV cure coatings to a wide range of plastic materials.
December 2015