When processing components using metal injection molding (MIM), binders are extremely important. Multi-component combinations of several polymers make up the architectural binders. Usually, a binder is made up of a core component to which different additives such as plasticizers, stabilizers, and dispersants are added.
Binders are primarily used to help shape the component during injection molding and to give the formed component strength. Until the sintering process begins, the metal particles are held together and shaped by the binder. The binders are combined with metal powders to create feedstocks, which are then utilized as injection molding starting materials. After molding, binders are taken out before the component is sintered.
The dispersion of metal particles, the shaping process, the size of the shaped component, and the final characteristics of the sintered component are all impacted by the binders’ characteristics.
When it comes to metal particles, the binder should have a low contact angle. Better binder wetting to the powder surface due to the low contact angle will facilitate mixing and molding. The metal particles and the binder ought to be inert in relation to one another. Metal particles shouldn’t react with the binder, and the binders shouldn’t be broken down or polymerized by the metal particles.
Several rheological conditions must be met by the binder powder combination (feedstock) in order for the components to be successfully molded without developing any flaws. For successful molding, the feedstock’s viscosity should fall within a certain range. Powders and binders will separate during the molding process if the viscosity is too low.
Conversely, an excessively high viscosity will hinder the mixing and molding procedure. The feedstock should have the property of a significant rise in viscosity upon cooling, in addition to the need for an optimal viscosity range during the molding process.
Binders can significantly increase the carbon footprint of petroleum-based interior architectural paints. Paint compositions can lessen their environmental effects and carbon footprint by using bio-based binders. Carbon dioxide (CO₂) is transformed into biomass by plants using the energy from sunlight during photosynthesis. The sequestered carbon can contribute to a reduction in the total amount of CO₂ in the atmosphere when biomass from these plants is used as feedstocks on a large scale. Furthermore, as the emissions linked to fossil feedstocks are decreased, using plant-based feedstocks in binders instead of fossil feedstocks lowers the CO₂ footprint.
How can we tell if sustainable solutions are effective? is a question that frequently accompanies their assertions.
Apart from the bio-carbon content, other sustainability advantages include lowering carbon emissions, substituting safer ingredients for substances of concern, and lowering volatile organic compounds (VOCs) from the paint formulation. To guarantee that bio-based architectural binders are devoid of purposefully added perfluoroalkyl substances (PFAS) and alkylphenol ethoxylates (APEO) without sacrificing performance, companies have taken advantage of the study on compounds of concern. Additionally, these binders are low in volatile organic compounds (VOCs) and can be used to manufacture paints with ultra-low VOC level criteria of less than 5 g/L.
