Water Based Resins & Binders For The Coatings Industry
There are several classes of water based resins and binders and within those classes, a plentitude of products to choose from. Water based products have gained strong popularity versus their solvent based counterparts through continued technological advancements in the last quarter century. A lot of this is driven by VOC regulations, worker safety/exposure and other environmental concerns. Solvent based products still have a place for use; water based products are driving the evolution of the coatings industry. The uses for these types of coatings are wood finishes, architectural coatings, cement, pavement and infrastructure coatings, elastomeric roof coatings, machinery, and heavy equipment, textiles and fibers, paper, and leather coatings. Coatings are used in many facets of our lives and the possibilities continue to evolve.
The binder classes can include 100% acrylic, styrene, styrene acrylic, butadiene, vinyl acrylic, acrylic-epoxy, acrylic – urethane hybrids, urethane dispersions of polyether, aromatic, and aliphatic urethanes, to name a few. Some of the performance choices within the product classes can include but are not limited to: self-crosslinking (resins that self-crosslink at ambient air temperatures with minimal or no need for external crosslinking agents like isocyanates/poly aziridines/carbodiimides ), low or no volatile organic compounds, formaldehyde free, minimal MIT content or MIT alternatives, APEO free, and more.
There are products that can contain photoinitiators, UV absorbers, stabilizers, blockers, and gaining momentum. These are resins that can have a flame retardant or water repellent encapsulated into the polymer backbone as compatible with the polymer matrix. With encapsulation onto the backbone of the polymer matrix, this process can minimize or at times eliminate the need to pre or post treat a substrate with a flame retardant or water/oil/stain repellent, thus saving extra steps in the manufacturing process which can result in time/handling/labor and energy cost benefits. When one chooses a resin or binder it can be a very complicated endeavor. One has to consider environmental compliance-downstream affects, price, and packaging-delivery options before they even get to thinking about the chemistry itself, then one has to evaluate the following:
- Target lifespan of the coating
- Wetting/flow/open time/leveling
- Recoatability
- Tackiness or brittleness – TG of the coating
- Elongation/Elasticity/Flexibility
- Adhesion/cohesion wet and dry
- Abrasion wet and dry
- Blocking
- Freeze/thaw efficiency where applicable
- VOC
- Viscosity or rheology of the resin
- MFFT- Minimal film formation temperature
- Particle size
- How the coating will stand up to wear and tear such as washability
- Scrubbability
- Stability with the colorants that may be involved-compatibility
- Cure times or process in manufacturing conditions,
- Resistance to solvents
- Weathering resistance including uv resistance
- Salt and water resistance
- Traffic wearing
Combine all this with the multiple ways a coating can be applied such as roll, spray, brush, pad, curtain, calendar, knife/air or forward-reverse synchronized roll coating machines and one can see making the right choice can be a daunting task.
When all is done properly however, the end results can be very beneficial in regards to life extension of the coated substrate, aesthetics, serviceability, enhanced performance, and of course energy savings.
Depending on the manufacturing facilities process or the products field of application, the curing process can include hot air tunnels, gas fired infra-red, UV/EB radiation or natural outdoor curing from the sun, are all to be considered when choosing the right resins or binders for the job. There’s an old saying in the coatings world, when it’s finished it’s finished, with our product lines of Meracryl, Merithane, Sorabind and Sorathane resins, our technical coatings staff stand ready to help you formulate the proper systems for your resin, binder and coatings requirements, and we offer custom blending of resins to offer turnkey or close to turnkey products, at First Source Worldwide, we help you finish!
About the Author: Jerry Fitzpatrick
