The individual service manager is not generally aware of the large amounts of cleaning solvents that are used in the electronics industry. Setting aside those that are used in 'closed" systems (where release of solvents to the atmosphere is minimized or virtually eliminated), hundreds of thousands of gallons of cleaning solvents are use each year in the electronics industry. The environmental impact of these is considerable, as a substantial portion of them evaporate into the air.
Not only do solvents present a potential hazard to human health in the workplace, they often combine with other chemicals, forming layers of often-phototropic smog. While few solvents have the potential impact of the chlorofluorocarbons, they are nevertheless of considerable concern to environmental authorities and concerted efforts are underway to limit their use. A measure of things to come are California (and other States) restrictions on the amount of solvents permitted in paints and other coatings, and strict regulations governing processes which have the potential to release any solvents into the atmosphere (such as compressed-air based paint spraying).
Manufacturers and service organizations operating coast-to-coast are finding it increasingly difficult to cope with the numerous and differing standards as to what an acceptable cleaning solvent and its permissible level of usage. This makes the use of "centralized stores" purchasing, with its attendant economies, quite hard to manage. Indeed what may be legal in one area of a state may well be banned in another area of the very same state.
Stabilant 22 is a virtually non-toxic liquid polymer that is applied to electromechanical contacts, and then left in place. Unlike a cleaner it is not "hosed" on the connector and wiped off. Very little must be used as a coating of less than 0.5 to 1 mils in thickness are usually sufficient to treat the connector.
Unlike cleaners, Stabilant 22 is an initially non-conductive material that, under the action of an electric field gradient, switches to a conductive state. This gradient designed so that the switching action takes places only within the mating contacts and NOT between adjacent contacts. Thus there is no leakage, and the material can be used to coat an entire connector at a single application.
Generally, Stabilant 22 imparts the reliability of a soldered joint to an electromechanical contact without forming a physical bond.
Stabilants have been in some field trial applications for over fifteen years now, without showing any sign of reduced effectiveness. The material has a high molecular weight and a very low vapor pressure, thus it is not prone to evaporation.
Once again let us emphasize the point that unlike some other contact treatments containing oils, Stabilant 22 will not cross-link when exposed to certain materials such as high sulfur brass, or when used on connectors having elastomer or most plastic components with accelerant and curing agents, or when used on contacts where cross-link promoting agents are present in the environment. The phenomena of 'varnishing' does not occur with Stabilant 22.
The material is available as a concentrate, Stabilant 22 or in a solvent-diluted form, as Stabilant 22A or Stabilant 22E (either with isopropanol or ethanol), The diluted material has 4 parts of solvent to 1 part of Stabilant 22 by volume, and is much thinner, and therefore easier to apply to contacts such as socketed IC's.
Some end users prefer to buy larger quantities and use industrial syrettes to apply the material onto connections. Camel's hair or sable brushes can be used to brush it on card-edge connectors. Cards can also have their edge connectors dipped into the dilute material.
Solvent burden/year is the average amount of cleaning solvent used per year to keep a piece of electronic equipment operating over its useful life.
In the trial use of a solvent to clean contacts in an older computer, we found that it took about 20 mL of an isopropanol-perchloroethylene based material to clean a 100-contact card-edge connector. Even though some was left on the wiper used, it too evaporated. The equipment became erratic in operation four months later, and the contacts had to be re-cleaned. In the proceeding year, the same approximate pattern had been repeated to the point where we could safely say that the annual solvent usage for that set of contacts was about 60 mL. The next time that we had the equipment malfunction we used 2mL of Stabilant 22A which released 1.6 mL of isopropanol to the atmosphere. No further service was needed for three and a half-years, (the equipment was sold in working order), thus the solvent burden of that connector was about 0.46 mL/year. This is a reduction in solvent burden of 130:1.
Had the concentrate (Stabilant 22) been used there would have been no solvent burden as the vapor pressure of that material is very low and virtually no evaporative losses take place.
Stabilants do not contain any ODC's such as CFC'S, HCFC's or Trichloroethylenes, nor are such chemicals used in their manufacture.
Neither the Stabilants themselves, nor any of the inks used on their labels or packaging, contain Lead, Cadmium or Hexavalent Chromium.
Neither Stabilant 22, Stabilant 22A, or Stabilant 22E, are subject to the TSCA (Toxic Substance Control Act) nor are they reportable under SARA Title 111.
As noted, Stabilants are not a chelating agents and thus will not cause heavy metals to become concentrated in effluents. And while there is no evidence of toxicity to marine or littoral life, we recommend, subject to local ordinances, that surplus or contaminated Stabilant materials be destroyed by incineration.
For United States end-users:
Stabilant 22 is not a hazardous waste when discarded as defined in 40CFR261.337
Stabilant 22 is not a halognated solvent when spent as defined in 40CFR261.317,
The total Organic Carbon Content (TOC) of Stabilant 22 is 28%
As the useful life of the Stabilants is generally well in excess of five years, the reduction solvent burden when using either the isopropanol diluted Stabilant 22A or the ethanol-diluted Stabilant 22E, could be as much as 200:1, by volume alone, for the connector in a piece of electronic equipment.
Granted that the Mean Time Between Failure of 4 months is much shorter than a typical MTBF for most electronic equipment, the amount of solvent used was also minimized by careful application. While even a 50:1 reduction in solvent burden is worthwhile, the total elimination of solvent burden by the use of the concentrate Stabilant 22 is even more significant, Stabilant 22 is not a chelating agent, a matter of concern to both those industries producing heavy metal waste, and to the Nuclear power generating industry.
As Stabilant 22 contains no solvents and has an exceptionally low vapor pressure, it is technically not subject to the various rules and regulations governing coatings such as paints and varnishes, and in California's Southwest, the amounts of isopropanol or ethanol (as a solvent) involved in the use of Stabilant 22A or Stabilant 22E, are so small, on a daily basis that there is generally no problem in obtaining a letter of exception from the appropriate agencies. As Stabilant 22A or Stabilant 22E are not packaged in quantities sufficient to be affected the various acts it does not require special labeling in California.
Revision 4
Stabilants are a product of Dayton Wright research & development and are made in Canada
NSCM - CAGE Code / NATO Supplier Code 38948
15 mL of Stabilant 22A (isopropanol-diluted) has NATO Part # 5999-21-900-6937
15 mL of Stabilant 22E (ethanol-diluted) has NATO Part # 5999-21-909-9984
The Stabilants are patented in Canada - 1987; US Patent number 4696832. World-wide patents pending. Because the patents cover contacts treated with the material, a Point-of-sale License is granted with each sale of the material.
Stabilant, Stabilant 22, and product type variations thereof are Trade Marks of D.W. Electrochemicals Ltd.
© Copyright 1987, '88. '89, '90 - D.W. Electrochemicals Ltd. This note may be reproduced or copied, provided its content is not altered. The term "contact enhancer", © 1983 Wright Electroacoustics.
NOTICE: This Application Note is based on customer-supplied information, and D.W. Electrochemicals is publishing it for information purposes only. In the event of a conflict between the instructions supplied by the manufacturer of the equipment on which the Stabilant material was used, and the service procedure employed by our customer, we recommend that the manufacturer be contacted to make sure that warranties will not be voided by the procedures.
While to our knowledge the information is accurate, prospective users of the material should determine the suitability of the Stabilant materials for their application by running their own tests. Neither D.W. Electrochemicals Ltd., their distributors, or their dealers assume any responsibility or liability for damages to equipment and/or any consequent damages, howsoever caused, based on the use of this information.
Stabilant, Stabilant 22, and product type variations thereof are Trade Marks of D.W Electrochemicals Ltd.
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