Case Report: Green Synthesis of Hybrid Non-Isocyanate Polyurethane/ Green Polyurethane developed by Hybrid Coating Technologies

Author: Alonzo Bell

Date Published: 04/02/2023

Case Report: Green Synthesis of Hybrid Non-Isocyanate Polyurethane/ Green Polyurethane developed by Hybrid Coating Technologies.

Case Report: Synthesis of Hybrid Non-Isocyanate Polyurethane/ Green Polyurethane by Hybrid Coating Technologies

The focus area of the award: greener synthetic pathways, greener reaction conditions, and design of greener chemicals

The Winners of the Green Chemistry Awards of 2015, who produced synthesis routes to develop hybrid non-isocyanate polyurethane (HNIPU). Isocyanates are known as toxic hazards to humans and wildlife when combusted and can produce harmful amines, nitrogen oxides, hydrogen cyanide and carbonate molecules.

This new innovation considers molecular weights of different amine groups. Some low molecular weight amines can have acute toxicity and be corrosive (via conventional synthesis). HCT, also considers high molecular weight amines which can be less toxic and more stable for synthesis via non-isocyanate reaction. 

By exploring alternate routes to synthesize polyurethane, HCT was able to develop non-isocyanate highly efficient products especially for painting and flooring. Hybrid Coating Technologies benefits from this innovation includes; increased wear resistance which is two times better than premium conventional coatings and adhesion properties which are 10-30% higher than in previous methods. 

Category: small business, academia, special environment benefit

These companies currently use conventional methods of polyurethane synthesis; Bayer, BASF,  Woodbridge, Mitsubishi & Co Plastics, Dow, Tosoh Corporation , Huntsman International LLC, DIC Corporation, Eastman Chemical Company and many more. 

Synthesis of non-isocyanate polyurethane products is coming into competition with the conventional methods due to its feasibility, cost competitiveness, and removal of the toxic reactants in the production process. With the use of (HUMS) which means hydroxyalkyl urethane modifiers, derived from first generation biofuels, the substances are reacted with polyamines with primary amino groups, mono/pericyclic carbonates, and epoxy oligomers. The (HUMS) are now used in acrylic based coatings such as foams, paints, coatings, adhesives, and insulation.  

Some companies which have implemented green polyurethane technology includes; Hybrid Coating Technologies/Nanotech Industries, Industrial FInishes & Systems, National Renewable Energy Laboratory (NREL),  EuroTech,  Strategic Environmental Research and Development Program (SERDP), Momentive Performance Materials Inc., and Bio NIPU. 

The challenge/problem that it addresses: background of the reaction/process/technology

Conventional Polyurethane paints can be very permeable and porous. The hybrid non-isocyanate polyurethane alternative has enhanced properties while proposing minimal to no threat to human or public safety. According to Hybrid Coating Technologies, this green technology can save customers 30-60% on application costs.  

The product via non-isocyanate synthesis is a cross linked a-polymer chain and a b-hydrourethane molecule with enhanced structures and stoichiometry. With the use of Hydroxyalkyl Urethane Modifiers (HUMS) derived from first generation biofuels, the substances are reacted with polyamines with primary amino groups, mono/pericyclic carbonates, and epoxy oligomers. 

Many countries are looking to ban polyurethane manufacturing in the near future such as China, Europe and some states in the US. Europe has been very progressive noticing the effects of polyurethane products, and minimizing their production or use. For example, swimsuits made for the olympics in Europe have been banned for their polyurethane foams. As of now Europe has adopted the REACH program which prohibits pure polyurethane products from being manufactured solely on its own. 

In California, polyurethane spray foams and flame retardant sprays have been restricted and prevented from being used. Isocyanate products due to their toxicity to humans and wildlife are monitored and regulated by the EPA.  

The improvement/innovation: for instance:  reagents, solvents, conditions, waste generation; 

Conventional Methods PU Synthesis

In one method of conventional synthesis the reactants are polyols (r-chain bonded to a diol), methylene di-phenyl di-isocyantate (MDI), and toluene di-isocyanate. The di-isocyanates react with the diols to complete the reaction. The product forms a polyurethane molecule. Common reactants via synthesis this route are; Tolylene-2,4-diisocyanate (2,4-TDI), 1,4-Phenylene diisocyanate (MDI), and Hexamethylene diisocyanate (HDI). These isocyanate polymers are manufactured by Bayer Mondur and BSF Lupranat. 

In another process; Hexamethelene di-siocyanate and 1,4-Butanediol are reacted with Maghnite-H⁺ to produce the molecule polyurethane. Overall these molecules are porous and permeable, an issue which non-isocyanates synthesized polyurethane can improve. 

Hybrid Non-Isocyanates Synthesis

HCT Developed a specific epoxy amine hydrourethane sequence which has high molecular weight amines which are less toxic, as opposed to low molecular weight amines which can show acute toxicity and be corrosive (via conventional synthesis).

In this route, the hydrolytic stability of the new product is increased which means it will not decompose easily upon contact with water because of strong intermolecular bonding forces. With its enhanced properties, it is resistant to different temperature variances.The non-isocyanate polyurethanes are also non-porous and non permeable structures unlike conventional polyurethanes produced with isocyanates. 

Advantages to this synthesis route include properties such as longer shelf lives of products, heating and cooling resistance, durability, and decrease in corrosion. Impressively, HCT were able to form polyurethane without including any isocyanate functional groups in the reaction. The chemical is also becoming cost-effective and competing with conventional methods. Hydroxyalkyl Urethane Modifiers, (HUM) and other non-isocyanate reactants may improve bonding abilities in the product as well. Another ecological benefit of the innovation is that it lacks the presence of volatile organic carbons (VOC) which can be hazardous to the surrounding environment.

 Examples of applications of the innovations  

Some examples of the innovation are; Non isocyanurate foams for heating & cooling and insulation.  Non-isocyanate coatings for paints are also manufactured for the automobile industry with enhanced resistance and durability properties. Nano Shield and FireProofing Coating are also new technologies introduced by Hybrid Coating Technologies.

Non-isocyanate polyurethane technology for hardwood floors (multi-layered floor applications) has also been developed. By utilizing this synthesis route, one layer of non-isocyanate polyurethane efficiently replaces 3 layers of epoxy resins, which shows the product’s improvements through green polyurethane synthesis. In comparison to conventional polyurethane the green polyurethane is up to four times stronger and endures two times as much abrasive wear. The innovation helps to improve the safety of polyurethane production and consumption, while also being an affordable and feasible alternative to conventional polyurethane synthesis.  

References

California temporarily suspends regulatory action on spray foam. (2021). Chemical Watch. https://chemicalwatch.com/218247/california-temporarily-suspends-regulatory-action-on-spray-foam

Hybrid Coating Technologies Expands Technology with New Polyurethane Patent to Cover Hardwood Floors. (2014). News File. https://www.newsfilecorp.com/release/10881/Hybrid-Coating-Technologies-Expands-Technology-with-New-Polyurethane-Patent-to-Cover-Hardwood-Floors

Korea Production: SR: Polyurethane Resin. (2018). CEIC. https://www.ceicdata.com/en/korea/production-by-major-products/production-sr-polyurethane-resin

Liang, C., Alvarez, U., Gallant, E., Gillis, P, Marques, Y, Abramo, G., Hawkins, T., Dunn, J. Material Flows of Polyurethane in the United States. ACS Publications. https://pubs.acs.org/doi/10.1021/acs.est.1c03654

Plaste Mart. Global demand for Polyurethane to rise with growing need towards energy efficiency. (2016). Smartech Global Solutions Ltd.http://www.plastemart.com/plastic-technical-articles/global-demand-for-polyurethane-to-rise-with-growing-need-towards-energy-efficiency/2029

Polyurethane Global Market Report 2023 – By Product Type (Coatings, Adhesives And Sealants, Flexible And Rigid Foams, Elastomers, Other Product Types), By Raw Material (MDI, TDI, Polyols), By End User Industry (Furniture, Construction, Electronics And Appliances, Automotive, Footwear, Other End Use Industries) – Market Size, Trends, And Market Forecast 2023-2032 . The Business Research Company. (2023). https://www.thebusinessresearchcompany.com/report/polyurethane-global-market-report

Stachak, P., Lukaszewska, I., Hebda, E., Pielichowski. Recent Advances in Fabrication of Non-Isocyanate Polyurethane-Based Composite Materials. (2021). PubMed Central. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8269506/ .  doi: 10.3390/ma14133497