We recently participated in a valuable, thought-provoking workshop;1 this annual conference deals with the confluence of military requirements for critical applications of environmental, regulatory and/or legislative changes, and of practical, achieved approaches to production and maintenance of product quality. The emphasis is on surfaces, both cleaning and coating, and on contamination control. The conference is particularly valuable for the forthright, sometimes pointed comments of the speakers and the similarly frank, incisive comments and questions from the audience. This month we will discuss a few topics presented at the workshop.
1 14th Annual International Workshop on Alternatives to Toxic Materials in Industrial Processes (Formerly International Workshop on Solvent Substitution), Scottsdale Arizona, Exchange Monitor Publications & Forums, (December 8-11, 2003).2 M. Duncan, ibid3 K. Kristoff, ibid.4 Section 9002 of the Farm Security and Rural Investment Act of 2002 (FSRIA), 7 U.S. C. 8102. See http://www.biobased.oce.usda.gov/public/index.cfm5 Federal Register, Proposed Rule, Biobased products designation guidelines for Federal procurement, 70730-70746, (December 19, 2003).6 B. Kanegsberg, 14th Annual International Workshop, op cit.7 S. Apel, ibid.8 C. LeBlanc, ibid
Biobased products, derived from renewable plant or animal materials, the topic of several presentationseg. 2,3 raise both opportunities and potential contamination control issues. Given recent legislation4 and near-term regulations,5 the Federal government will, in most cases, have to purchase biobased products. As a consequence, biobased products are likely to be strongly encouraged, even in the private sector. Research and development dollars are being focused on biobased lubricants, oils, and other metalworking fluids as well as on biobased cleaning agents. There are positive aspects to this trend. Products based on renewable resources are important economically and politically. In addition, such products offer the possibility of new, favorable characteristics. For example, nutritionists and chemists at pharmaceutical companies continually find hitherto unknown compounds in plants.
At the same time, introduction of biobased products raises potential contamination control issues. Where biobased products are used for lubricants and metalworking fluids, processes for their effective removal must be devised. In addition some biobased products such as d-limonene are very effective in removing adherent soils. However, d-limonene leaves a residue, albeit one which can be readily removed by sequential rinsing with a more volatile solvent such as isopropyl alcohol.6 Soy-derived materials (methyl soyate) have similar properties. As such products are introduced for more critical applications, establishing appropriate cleanliness verification procedures and surface quality procedures will be imperative.
Contamination Control, Cleanliness Standards
One case study7 involving manufacture of space shuttle windows demonstrates that contamination may still be present even if it has not been observed. An improvement in the optical inspection technique of the windows revealed a previously undetected haze. Subsequent investigation led to the identification of the source of this contamination and to development of a method for removal of the haze.
Knowing the Variables
Results of a survey of implementation of cleaning processes were presented(8). The study, sponsored by the Toxics Use Reduction Laboratory (TURI) of University of Massachusetts, Lowell, involved groups who had worked with TURI to develop alternative surface cleaning processes. Over 70% of the respondents did not know the suppliers or trade names of the cleaning agents currently in use at their company. Understanding the cleaning process is a key to successful contamination control. Changes in soils, materials of construction, or product design, potentially impacts contamination level. Cleaning is an important part of contamination control; and, without a clear understanding of the nature of the cleaning agent, process monitoring is incomplete.
Asking the Questions; the Issues
No resource or event is likely to answer all of oneís questions about contamination control. A key value of this workshop is that contamination control, cleanliness and performance issues are addressed in a forum where frankness, honest discussion of issues, and public interchange between presenters and other attendees is encouraged. As important, those involved in technology advancement and in day to day product performance, interact not only with each other but with those who develop environmental regulations. Because both performance requirements and constraints (e.g. environmental, legislative, costs) are likely to increase, such interchanges continue to be not just relevant but crucial.