Bio-Based Coatings Based on Monomer-Grafted Alkyd Ester Resins (RFT-335)
The utilization of plant or vegetable oils and other renewable resources for commercial applications is gaining momentum as a result of the emerging disadvantages originating from the use of petrochemicals (that is, higher oil prices, waste disposal, climate change, etc.). As the coatings industry seeks to decrease its dependence on petrochemicals, resurgence in the use of natural oils as eco-friendly starting materials is increasing.
Scientists working at NDSU have discovered monomer-grafted sucrose ester resins that were synthesized and characterized for their coating properties. Solvent borne resins were prepared by polymerizing styrene in the presence of the sucrose ester resins. At a composition of 50% styrene and 50% sucrose ester, the resulting coatings had extremely fast tack-free drying times, comparable to a commercial styrenated alkyd resin. However, the styrenated sucrose ester resin had a much lower viscosity than the commercial resin, meaning that higher solids coatings can be prepared. In addition, water dispersible resins were prepared by grafting a mixture of styrene and acrylic acid with the sucrose ester resin. These were crosslinked with a melamine-formaldehyde resin to yield coatings that exhibit excellent hardness, adhesion, and flexibility.
- Bio-based coatings; renewable, biodegradable, and less impact on the environment.
- Produce coatings exhibiting excellent hardness, adhesion, and flexibility.
- Prepared coatings have extremely fast, tack-free drying times.
- Uses soybean/vegetable oils and other renewables rather than petrochemicals
- Produces flexible and tough surface coatings.
This NDSU invention relates to the monomer-grafting of partially esterified sucrose esters (PESEs) of fatty acids from soybean oil to yield styrenated PESEs (SPESEs) by grafting styrene and styrene and acrylic acid on the fatty acid backbones using t-butoxy radicals as an abstracting initiator. Not all of the unsaturated sites need to be consumed on the fatty acid backbone of the alkyd resin compositions to allow for and encourage cross-linking by autoxidation using, for example, a cobalt drier after the reaction and upon coating. The chemical properties of the resulting SPESEs have comparable coating properties and viscosity to a commercial styrenated soya based alkyd at a higher solids content. SPESEs were also made to be water-reducible by grafting a copolymer composed of styrene and acrylic acid. The extent of neutralization was maintained at 75% for all formulations to facilitate water dispersion. Cross-linking using melamine-formaldehyde resin resulted in cross-linked films with high solvent resistance while maintaining coating flexibility.
This technology is patent pending with fully preserved PCT patent rights and is available for licensing/partnering opportunities.
Henry Nowak, Technology Manager
NDSURF Tech Key RFT, 335, RFT335
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