The objective of this SEED Statement of Need (SON) is to develop solvents that do not contain known and emerging chemicals of concern in their formulations and show relevancy for military non-aqueous cleaning applications. These solvents, used mainly as cleaning and degreasing fluids, need to meet relevant military performance requirements including cleaning time, compatibility, and flammability, while eliminating chlorinated and fluorinated compounds, volatile organic compounds (VOCs), hazardous air pollutants (HAPs), and other regulated materials. Relevant requirements for military cleaning solvents can be found in specifications such as ASTM D 4376, MIL-T-81533, MIL-PRF-680, and MIL-PRF-32295.

Proposals should include a plan to conduct a Sustainability Analysis[1] of appropriate proportion to the proposed research and development. Proposals should establish a lifecycle framework that can mature as the technology or process advances through the acquisition process. This tiered approach aims to develop and document a minimum data set at each stage of research and development that can be used to make informed decisions and streamline transition to an acquisition program. The Sustainability Analysis may include varying depths of data and information that can inform: the goal and scope of an analysis; the identity and quantity of relevant inputs and outputs to the system; and the estimation of life cycle impacts and costs.

The use of emerging chemicals of concern in vapor degreasing solvents is at risk due to regulation and potential lack of production. Program Managers, installations, and Warfighters across all Services would benefit from new, innovative and improved weapons systems vapor degreasers and cleaners. These would reduce worker and environmental regulatory risks and improve asset operational performance and readiness. 

Solvents and degreasers are used to effectively remove grease, oil, tar, etc., from military equipment to increase their operating efficiency. Cleaning products and contact cleaners are used in military repair facilities for vapor degreasing, flux removal, and to clean fiber optic connectors in secure link manager assemblies (SLMAs) and primary modem assemblies (PMAs) and aerospace oxygen systems. Non-destructive testing (NDT) solvent cleaner/remover is used for pre-cleaning before NDT and for removing excess surface penetrant from an inspection area before applying developer during liquid penetrant testing. 

Vapor degreasing is a cleaning process that uses vaporized solvents to remove oils, greases, and waxes from equipment. The simplest vapor degreasing unit contains a solvent sump and a headspace where the solvent vapor is concentrated. The heated sump at the bottom of a vapor degreasing unit boils the liquid solvent to create a vapor that displaces the air commonly referred to as a vapor blanket. The vapor rises and fills the headspace of the unit, which is contained by the cooling system at the open top of the unit. Thus, the solvent undergoes cyclic vaporization and condensation processes. The temperature difference between the vapor blanket and colder hardware to be cleaned allows for the vapor to condense on the part and dissolve any oil, grease, or wax. The part is cleaned by the condensed solvent containing the dissolved contaminant. Once the contaminant is removed from the hardware, the part dries immediately by drawing the hardware through the cooling system. Additionally, the hot and cold zones of the unit allow for the solvent mixture to be separated and recycled back into the process over hundreds of times, making the process more efficient and cost effective.

Vapor degreasing solvents leave no residue and have no flash or fire point to enable safe use. Traditional solvent-based cleaners have been based on chlorinated solvents, including trichloroethene (TCE), perchloroethylene (PERC), n-propyl bromide (nPB) and 1,1,1-trichloroethane. However, various regulations have resulted in a high degree of replacement of these solvents with ones that have lower chlorine content. To enable these to be used safely, additional chemical additives must be used to eliminate fire hazards. Modern vapor degreasing solvents utilize trans-dichloroethene (TDCE) and require addition of significant percentages of fluorinated chemical(s) for fire suppression. This azeotrope chemistry allows the vapor degreasing process to occur at the boiling point of the solvent without flammability concerns and without changing bath composition. The chemicals utilized to enable this azeotrope are currently non-regulated chemicals of concern. 

It is important that any alternative vapor degreasing formulations are nonflammable and compatible with the materials being cleaned, which are typically polymers, elastomers, and metals. These key requirements, along with others, can be found in specifications such as ASTM D 4376, MIL-T-81533, MIL-PRF-680, and MIL-PRF-32295. The DLA assist tool can be used to download these specifications: https://assist.dla.mil/online/start/

To meet the objectives of this SEED SON, proposals should not exceed $250,000 in total cost and approximately one year in duration. Work performed under the SEED SON should investigate innovative approaches that entail high technical risk and/or have minimal supporting data. At the conclusion of the project, sufficient data and analysis should be available to provide risk reduction and/or a proof-of-concept. SEED projects are eligible for follow-on funding if they result in a successful initial project.