Metals are inherently unstable and have a tendency to revert to their more stable mineral forms due to chemical reactions with their environment. At a high level, that's corrosion.

Corrosion silently deteriorates metal, slowly degrading material integrity over time. The reaction between the metal and its environment - rain, snow, humidity, salt air, chemicals, etc. - begins when water and oxygen in the environment come into contact with the metal. La expansión de volumen del óxido es, aproximadamente, de dos a cuatro veces superior que la del metal original. Esta expansión del volumen del óxido causa agrietamiento en la capa de óxido, lo que habilita el ingreso de agua y oxígeno, que, a su vez, genera más óxido.

How quickly corrosion causes deterioration, and the kind of corrosion depends on the metal type and environmental conditions - and the metal protection used to coat the substrate. Two coating technologies that are widely used to deliver corrosion protection for a variety of applications include flash rust inhibitors and adhesion promoters. These additives are used to protect metal substrates like ferrous metal, zinc alloy and aluminum from corrosion and improve direct-to-metal adhesion, as well as intercoat adhesion.

Cómo superar los desafíos vinculados con la corrosión

Protecting metal from corrosion presents multiple challenges, which can depend on factors like metal type, environmental conditions and the end-use application. Cost and complexity is one of the challenges to overcome, especially as end users want to minimize costs by reducing the number of coats needed. More end users want to move away from a primer, midcoat and topcoat and more toward direct-to-metal coatings (DTM). With DTM coatings, one layer of coating has to do the same job of providing adhesion, corrosion and resistance to weathering that was previously done by three layers of coatings.

VOC regulations are another challenge, which has meant moving to more water-borne coatings. Not all water-borne coatings provide the same performance as solvent-borne coatings, which is why additives that can enhance the performance of the coating are becoming increasingly more important.

Inhibidores de oxidación rápida

Flash rust inhibitors are called upon to enable the metal used in machinery, equipment, cans, coils and more to stand up to a variety of conditions that can cause corrosion. They prevent or delay the formation of flash rust on metal surfaces, which can happen when exposed metal surfaces rapidly develop a layer of rust due to exposure to oxygen and moisture in the air.

Flash rust inhibitors are always needed in water-borne metal coatings because water is used as a solvent, as well as in direct-to-metal (DTM) coatings because they come in direct contact with the metal without the use of a primer. As soon as water comes in contact with the substrate, it can begin forming flash rust. Los inhibidores de oxidación no se necesitan en el recubrimiento superior, porque ya se habría aplicado un imprimador.

Activadores de adhesión

Achieving strong adhesion between the corrosion protection coating and the metal substrate is critical for long-term performance. That's why adhesion promoting additives are used so the coating tightly adheres to the substrate to prevent water and other species from getting to the metal substrate, slowing down or preventing corrosion for an extended period of time. Water will eventually get to the metal, but a good adhesion promoter can significantly slow it down. Both adhesion promoters and flash rust inhibitors can be used simultaneously to deliver additional benefits.

Aditivos de protección contra la corrosión de Lubrizol

Lubrizol has developed multiple technologies to protect metal from corrosion and improve direct-to-metal adhesion, as well as intercoat adhesion. These additives are compatible in both water-borne and solvent-borne coating systems, and react with the metal to deliver desired properties without impacting the stability of the coating system. They can be incorporated as a component in DTM coatings, primers or wash primer formulations.

Lubrizol adhesion promoters and flash rust inhibitors are proven in a variety of applications, including:

• Recubrimientos OEM y VR de automoción
• Recubrimientos para latas
• Recubrimientos para bobinas
• Recubrimientos para transporte comercial 
• Recubrimientos líquidos para techos (para techos de metal)
• Recubrimientos protectores
• Acabados para metales generales

Lubrizol flash rust inhibitor technologies are designed to protect ferrous metal, zinc alloy and aluminum substrates. Lubrizol adhesion promoters are polymeric phosphate esters used to improve the adhesion of a wide variety of solvent-borne and water-borne coatings to metal substrates. They are proven to improve the adhesion of coatings to a variety of metal substrates. These additives are especially effective on aluminum, but also work well on cold-rolled and galvanized steel and can even improve adhesion to poorly prepared surfaces.

Resultados de la prueba de pulverización de sal que muestran la inhibición de la corrosión con un aditivo de Lubrizol a la derecha y sin un aditivo a la izquierda.

Resultados de la prueba de trama cruzada que muestran la adhesión con un aditivo de Lubrizol a la izquierda y sin un aditivo a la derecha.

Pasivación de pigmentos metálicos

Certain Lubrizol adhesion promoters can also be used to protect untreated metallic pigments, such as aluminum flake and mica-based effect pigments, from degradation in water-borne coatings by passivation of the pigment surface. La pasivación de la superficie del pigmento también puede mejorar la resistencia a la humedad de recubrimientos de efecto metálico con base acuosa. Passivation of untreated metallic and effect pigments using Lubrizol adhesion promoters is a cost-effective formulation strategy for achieving stable and consistent color and appearance matches in water-borne coatings.