Executive summary

Executive summary updated: August 22, 2025

ExxonMobil commissioned Sphera to conduct a cradle-to-gate comparative product carbon footprint study of their Proxxima™ resin system according to ISO 14067. This study would allow ExxonMobil and its stakeholders to understand the global warming potential (GWP) performance of their two-part resin and catalyst system versus alternatives. The GWP results of 1 liter of Proxxima resin system were compared to three alternative thermoset resin system formulations.

When comparing the Proxxima resin system (Proxxima resin + Proxxima catalyst) with its alternatives, a functional unit was used, expressed as one liter of formulated resin system. This is because some of the main applications of these resins are typically designed based on specific dimensions, such as in wind turbine blades and pipe coatings.

While the study considered both mass and a high value chemical (HVC) allocation methods, mass allocation was the default method as it is the best comparative basis for this study. Specifically, the data for the alternative thermoset resin systems are based on Managed LCA Content (MLC) 2022.2 (formerly known as GaBi database) which largely takes a mass/energy allocation approach. Allocation sensitivities were not tested for the alternative resin systems. It should be noted that, even with the implementation of the HVC allocation method, a more conservative approach, the Proxxima resin system is still much lower than the three alternatives.

The study is limited to the cradle-to-gate analysis assuming that the alternative products have similar usage and marginal GWP impact from the end-of-life (EoL) stage.

A cradle-to-gate carbon footprint of product (CFP) study comparing Proxxima resin system and alternative thermoset resin systems was conducted by Sphera Solutions, Inc. The study, commissioned by ExxonMobil, enables the understanding of the global warming potential (GWP) performance of the two-part Proxxima resin and catalyst system according to ISO 14067. The CFP estimates of 1 liter of Proxxima resin system were compared to three alternative thermoset resin system formulations that are commercially available: epoxy, polyurethane, and vinyl ester resin systems.

Primary data for the manufacturing of the Proxxima resin system, including the main feedstock, were based on market reports and expert estimates. Secondary data for the background systems and alternative thermoset resin systems were based on Managed LCA Content (MLC) 2022.2 (formerly known as GaBi database) and model using LCA for Experts (LCA FE) 10 (formerly known as GaBi software).

Compared with the three alternative thermoset resin systems, Proxxima system (Proxxima resin + Proxxima catalyst) showed an improved CFP performance on a cradle-to-gate basis (Figure 1). Note that since such comparison only concerns a single impact category, it cannot support comparative assertions about the overall environmental superiority of Proxxima system over the alternative thermoset resin systems covered in this study per ISO 14044 (ISO, 2006). However, the results can support comparative footprint statements per ISO 14067 and ISO 14026, with great care on the implications of assumptions on the functional unit, system boundary definition, allocation approach, data source, and other factors in the comparison. Sensitivity analyses to allocation methods and secondary data sources did not result in changes to the directional comparative estimates.

1. Raw material extraction / acquisition
2. Material processing

Life Cycle Inventory (LCI) Data Sources
Primary data for the manufacturing of the Proxxima resin system, including the main feedstock, were based on market reports and expert estimates. Secondary data for the background systems and alternative thermoset resin systems were based on Managed LCA Content (MLC) 2022.2 (formerly known as GaBi database).¹

Allocation Procedures

• Mass allocation for foreground data
• Allocation of background data (energy and materials) from the MLC (2022)¹

Geographic and Time Coverage
US manufacturing for Proxxima resin system. Secondary data for the epoxy system represents China, which is among the largest producers in the world. Secondary data for polyurethane and vinyl acetate (precursor of vinyl ester resin) systems are EU and US, respectively, which are selected based on data availability. It should be noted that the EU and US are also leading manufacturers of polyurethane and vinyl ester resin. The intended time coverage for the study is the year 2022 as the primary data collected is representative of this year. Background data (i.e., production of raw materials, energy, and ancillary materials) were obtained from Sphera’s MLC (2022.2) and are generally representative of the years 2018-2022. The results of the study are representative of 2022 and are expected to be relevant unless there is a significant technological change.

Cut-Off Criteria
All available energy and material flow data were included. In cases where no matching life cycle inventories were available, proxy data were applied.

Life Cycle Impact Assessment (LCIA) Method
IPCC AR6 GWP100, incl. biogenic CO2. Biogenic greenhouse gas emissions and removals were included in the calculations, but are not deemed significant and therefore are not documented separately in this summary.

Software: LCA for Experts (LCA FE) 10 (formerly known as Gabi software) developed by Sphera Solutions, Inc.¹

Third Party Review: Reviewed by an independent third-party critical review panel of three experts and confirmed to be conducted according to and in compliance with ISO 14067:2018.

Final Comment: As stated, this study is limited to the cradle-to-gate analysis, assuming that the alternative products have similar usage and marginal GWP impact from the EoL stage. Future comparative analysis for a specific end-use application on a cradle-to-grave base may provide opportunities for evaluating the carbon footprint of the Proxxima resin system over the full life cycle, however, it is not part of this study’s goal and scope.

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