R. Basu and R. Hulse
Honeywell International, Inc
Buffalo Research Laboratory
Buffalo, NY 14210 USA
In the past 20 years the solvent industry has gone through a great deal of change. In the early 1990's, CFC-113 and 1,1,1-trichloroethane were the workhorses of the industry.
The Montreal Protocol, to phase-out substances that deplete the Earth's protective Ozone Layer, was implemented in the mid 1990's to reduce chemicals with ozone depletion potential. After phase-out of the CFC solvents, the solvent industry fragmented to a variety of cleaning solutions.
The electronics industry was a large user of CFC solvents and many of these applications changed to aqueous based cleaners. Some of the industries moved to chlorinated and brominated solvents such as trichloroethylene and n-propyl bromide.
Other industries changed to no-clean fluxes. But those alternatives are now facing various problems: e.g. aqueous based cleaners use a lot of energy, require long drying times, use equipment that requires frequent maintenance, and require a large footprint; no-clean fluxes leave flux residues; and trichloroethylene and n-propyl bromide have toxicity issues. In response to these serious issues newer solvents and blends are being introduced in the marketplace.
In this pursuit the company developed a new low global warming potential fluorinated solvent for precision cleaning. This solvent has a mosaic of properties that make it a good solution in the solvent domain. It is non-flammable, has low toxicity, environmentally friendly, low surface tension, rapid drying, excellent solvency and a number of other favorable properties. In this paper we will review the properties and performance of the new solvent.
In this paper we have described the characteristics of a new solvent 1233zd(E) or trans-1-chloro-3,3,3-trifluro-1-propene which showed excellent promise as a solvent for defluxing and other cleaning applications. It has better environmental and toxicity properties compared with many other solvents in the marketplace today and can be used in vapor degreasers. It is also a stable, non-flammable product with reasonable compatibility with materials. Presently 1233zd(E) registration for solvent and other uses is underway in many countries.
The control and capture of a solvent for reuse should be a requirement for considering it as an alternative. It seems that, in this case, the proposed alternative (with a boiling point of 19C /66F) is expected to be used in vacuum or tightly closed systems. Many production facilities operate at 27C/80F and so would not be able to use this product.
Are there no other options available with a boiling point of 50C/122F or higher?
The delta T between ambient temperature and the boiling point is one of the critical parameters that actually dictates the "vapor cleaning time" in a vapor cleaning process.
