Chemical Engineering August 2020 - 28

Cover Story
Building a Sustainable
Coatings Infrastructure
Recent advancements in coatings technologies are driving the industry toward more
sustainable performance
Madison Sloan,
L. Elise Matolyak
and
Rebecca Chen
PPG
IN BRIEF
CHEMISTRY AND
FORMULATION
SUSTAINABLE SYSTEM
INTEGRATION
LIFECYCLE ASSESSMENT
G
lobally,
there has been an increase
in the number of chemicals
identified as " chemicals of
concern, " as well as restrictions
on the emissions of volatile organic compounds
(VOCs), resulting in new federal
initiatives and driving the development of
new manufacturing processes. One of the
more significant global initiatives for chemical
restriction is China's 13th Five-Year
Plan (2016-2020), which has identified environmental
protection as a key objective
[1]. China's Five-Year Plan is driving more
government regulations involving sustainability
and corporate social responsibility,
especially in manufacturing processes [1].
These regulations have a major impact,
specifically for paints and coatings, since
solvent-borne technologies will be restricted
in China by the end of 2020 [1].
Advantages
Thus, technological advancements in industrial
coatings are essential in this environmentally
conscious world to support
coatings end-users as they make transitions
in technology (Figure 1).
The complexity of changing the industrial
culture mandates that manufacturers consider
how best to implement sustainable
coatings systems. As manufacturers are increasingly
cognizant of the globalization of
products, they are keenly aware of environmental
requirements that must be considered.
This article covers some industrial developments
related to sustainable coatings,
as well as methods to facilitate their implementation
as an industry standard.
Chemistry and formulation
With increasing regulations and heightened
awareness about the environmental impact
TABLE 1. COATINGS TECHNOLOGIES TO REDUCE OR ELIMINATE VOCS
Technology
Powder [2]
· Can apply a thick coat in one
application (≥ 50 μm)
· Requires no mixing or stirring
· Has efficient material use (potential of
100% transfer efficiency)
High-solids [3, 4, 5]
· Can apply thick or thin coat
· Has less overspray compared to
conventional coatings
Waterborne [6,7]
· Can apply thick or thin coat
· Uses water for cleanup
· Is compatible with conventional and
electrostatic application equipment
Radiation-cure [8,9 ]
· Can apply thin coat (< 50 μm)
· Has efficient material use (nearly
100% transfer efficiency)
26
Limitations
· Requires special handling of heated parts
· Uses electrostatic application systems, making complex
shapes difficult to coat
· Difficult to incorporate metal flake pigments
· Is not applied to plastic substrates
· Does not eliminate solvent completely
· Has shorter pot life than conventional coatings
· Usually requires heating
· Flow properties and drying rates can fluctuate with humidity
and temperature
· High surface tension can lead to poor flow and dewetting
· Requires equipment compatible with waterborne systems
· Requires atmospheric-controlled storage conditions
· Tends to be low solid content
· Is typically best applied to flat materials
· Is limited to thin coatings
· Requires specific ultraviolet equipment
· Can result in yellow color
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Chemical Engineering August 2020

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