THE USE OF NANO ZNO IN PAINTS

Luis TormentoSetembro/2016

Introduction• Nanotechnology is seen as one of the key technologies of the future. Nanotechnology

refers to a wide range of scientific and technological phenomena which focuses on nanoscale (0.1 to 100 nm). It is the science of developing materials through individual control of atoms and molecules to create products that are thousands of times smaller than current technology allows for. The basis of this technology is to modify the inherent material properties such as color, abrasion resistance, conductivity, etc. the reduction of its size without modifying its chemical composition. nano-particles artificially produced have new properties which are important for the development of new products and applications.

• The composition of an organic coating (paint) may be may be a formulation simple or complex, with a variety of materials, each having a specific function. The formulations generally have three components designed to be permanent and serve specific functions in the dry film. These components are the pigment, carrier and additives. Pigments provide color and other functions. The vehicles commonly called ligands act as an adhesive to adhere the pigment particles to the substrate or to each other. Finally, the additives are chemicals which modify the coating properties in fluid or solid state.

Introduction• Organic coatings are essentially pigments dispersed in a solution in a

binder. The binder resin or the basic, is responsible for the physical or chemical properties of the coating, but these are affected by the nature and proportions of the pigments present. The volatile component function is to control the ink viscosity and to facilitate further manufacturing and application. You can not accurately determine which combination of properties will have a formulation. For this fact the applications for a specific paint formulation remains a "technological art". The appearance and application of nano-materials offer new opportunities for the coatings industry. The addition of nano-material coatings to improve the properties of conventional coatings, and produces new multifunctional coatings due to their small size.

Nano Particles Fillers for Coatings• Nano-particles are generally considered as the union of atoms or

molecules with a radius of 100 nm. 1 ray nanometer cluster has about 25 atoms, but many of them are in the cluster surface. Because of this, the intrinsic properties of nano-materials are different from conventional materials, because the majority of the atoms are in different media - in the conventional material atoms are distributed throughout the particle.

• Nano-materials account for almost as much in increased surface area, and are chemically very active due to having a very large number of molecules or atoms on the surface. Substances with high surface areas have physical, chemical, mechanical, optical and magnetic properties improved, and this can be exploited in a variety of structural and non-structural applications. Nano-particles used as fillers or pigments improve characteristics such as wear resistance, erosion resistance and corrosion resistance.

Nano Particles Fillers for Coatings

• Using a nano-scale component to obtain the desired properties. Due to higher surface activity of nano particles, they can absorb more resin compared to conventional pigments, and reduce the clearance between the pigment and the resin. Thus, the nano-particles increase the path of the corrosive species, and improve the protective properties and performance of the coatings. Nano-composites represent a new level in the various fields of science.

Nano Particles Fillers for Coatings

Nano ZnO in Paints and Coatings

• Studies have shown that nano-particles of ZnO and their effects in shape (structure) affect the anticorrosive properties. The particle size and form (structure) has a large effect on mechanical properties, permeability of the film to water vapor and efficiency in protection against corrosion. There is a connection between the size of the spherical particle and the anticorrosive efficiency, the smaller the particle size the better is the corrosion protection of the coating.

• Following is a table with the different properties presented by nano ZnO in various types of paints and coatings

Nano ZnO in Paints and Coatings

Material Characteristics

Polyurethane The ratio effect pigment / binder (P / B) in the anticorrosive properties of polyurethane coatings, applied on steel showed that the corrosion resistance (3.5% NaCl in water per 1000 hours) showed a P / B ratio = 0 . 3 and the common ZnO a ratio P / B = 1. This means that higher anti-corrosion property can be obtained with less amount of nano ZnO.

Acríylics acrylic paints with nano ZnO have better distribution of pigment, still have electrostatic and antibacterial function. Nano ZnO has higher antibacterial effect against Staphylococcus Colibacilus and Stafilococus.

Alkyd The nano ZnO combined with titanium dioxide, has anticorrosive effects, high grade antimicrobial and UV protection (UVA, UVB and UVC).

Nano ZnO in Paints and Coatings

Material Characteristic

Paints for wood Paints with nano ZnO cause moderate mortality in termites (94% in tests with untreated wood). The nano ZnO has a high degree antimicrobial and fungicide on untreated wood.

Navy paints The nanbo ZnO has an extremely harmful effect on the aquatic environment, particularly the aquatic flora and fauna. For this reason, the nano ZnO is used as a component in paints naval use, because due to their toxicity prevents fouling buildup on the paint. His exceptional ability to absorb UV radiation (UVA, UVB and UVC) makes it ideal for outdoor applications, giving additional protection to the resin increasing the durability of marine paint.

Nano ZnO in Paints and Coatings

Material Characteristic

Hygienic coatings Because of its enormous antibacterial power paints based on nano ZnO and titanium dioxide, are used in medical products, packaging for paints for use in pharmaceuticals, food and air conditioning systems. Other applications include hospitals, pharmaceutical units, food processing and places where high disinfection should be performed - do not forget your strong UV protection - to eliminate pathogens. Containers for water storage can also be painted with nano ZnO based paints due to its huge antimicrobial power.

Conclusion• The use of nano ZnO in paints offers many advantages, which we can

highlight:• Better appearance;• Smoother surfaces and easy to clean;• Best scratch resistance (scratch);• Anti-reflective nature;• Good adhesion to different materials;• Resistance to UV (UVA, UVB and UVC);• Good chemical resistance;• Reduced permeability to corrosive media, and therefore with improved anticorrosive

properties;• Optical clarity. For resonance effect in some nano ZnO becomes transparent;• The use of nano ZnO in antibacterial and antimicrobial applications, as well as its

fungicidal effect is a growing field, because these pathogens are becoming increasingly resistant to bactericides and chemical treatments. Nano ZnO is a natural treatment and have no evil power to humans

Conclusão

• Nota final:O nano ZnO apresenta a desvantagem de ser levemente amarelo, mas devido ao seu uso extremamente baixo esse efeito não se torna um problema. Caso necessite utilizá-lo em grandes quantidades sugerimos a combinação com dióxido de titânio (TiO2) para realçar a cor clara da tinta ou revestimento.

Contato

LT QuimicosAv. Pedro Severino Jr., 366 Cjto 35

04310-060 – São Paulo – SP – BrasilLuis TormentoNPD Director

Luis.tormento@ltquimicos.com.brTel: +55 (11) 5581-0708