General Background and Information

What Is Bromothane?

“Normal Propyl Bromide” (nPB) is the full chemical name for the active ingredient in the Bromothane solvents. It also can be called 1-bromopropane or 1-propyl bromide, and is a colorless, nonflammable organic cleaning fluid engineered to be used in vapor degreasers. It has the chemical formula C3H7Br and the CAS number 106-94-5.  Based on the element bromine, nPB is a unique liquid selected by MicroCare and Chemtura to be the cornerstone upon which the Bromothane family of cleaners is built.

Bromine is a halogenated material. It is related chemically to the other halogens, which means they are all in the same column on the periodic table of the elements (if you’re interested, see col. 17 on the right-hand side of the Table). Other halogens include chlorine, fluorine and iodine, all of which are widely used as cleaning products. nPB is a great replacement for the chlorinated solvents like perc and TCE, the old CFC cleaners, and more modern ozone-depleting hydrochlorofluorocarbons like HCFC-141b and HCFC-225, and the fully-fluorinated materials (PFCs).

What is DuPont™ Vertrel®?

Vertrel® is the brand name for a family of ozone-safe solvents made by the DuPont Company for precision cleaning. Specifically, the term Vertrel® describes a group of fluorinated solvents and specialty fluids. At their core, each product is based on HFC-43-10mee which is also known as 2,3-dihydrodecafluoropentane; the chemical formula for the material is C5H2F10 and the CAS Number is 138495-42-8. It is a clear, colorless liquid with “zero” ozone depletion and low global warming potential.

Unique physical properties of HFC-43-10 include a high density, low viscosity and low surface tension. These attributes, combined with its nonflammability, chemical and thermal stability, low toxicity, and ease of recovery by distillation, make HFC-43-10mee ideal for a broad range of applications including vapor degreasing and cold-wiping.

By itself, it is a very mild solvent, but the solvency can easily be enhanced by use of appropriate azeotropes of alcohols, hydrocarbons, esters, etc. Most of the commercial products also contain other ingredients, such as alcohols, trans-1,2 dichloroethylene, and/or HFC-365, which tailor the solvent’s performance to specific cleaning requirements. All but two of the Vertrel® products are true azeotropes or exhibit azeotropic-like behavior, which means they can be used repeatedly and safely in heated cleaning systems.


Which MicroCare Products Are Used to Deflux Circuit Boards?

Today’s electronics are often cleaned with either (a) MicroCare CMS defluxer, (b) DuPont™ Vertrel® SFR flux remover, or (c) Bromothane R. Each has different benefits and weaknesses; see the product specs for details.

Which MicroCare Products Are Used to Remove Oils and Grease?

The MicroCare fluids easily dissolve all types of oils, lubricants and even light greases. Once the oil is dissolved in the cleaning fluid, the oil will be removed from the parts and trapped in the “boil sump” of the vapor degreaser where it can be easily cleaned out during routine maintenance. The parts come out clean, dry and at room temperature.

For this application, try the following recommendations: (a) MicroCare® HDS degreaser; (b) DuPont™ Vertrel® SDG degreaser, or (c) Bromothane™ S.

Which MicroCare Products Are Used to Remove Particulate?

Another common chore for MicroCare fluids is displacement cleaning. In this application, the specific gravity of the MicroCare fluids and the very low surface tension of the solvent deliver cleaning results simply not possible with aqueous or hydrocarbon cleaners.  The addition of an alcohol or other polar solvent to a formulation is also very helpful in removing particulates from non-conductive surfaces such as plastics.  The polar solvent makes the formulation more electrically conductive and helps wickaway static charges which cause particulates to adhere to the surface.

For these applications, MicroCare normally recommends MicroCare CCA degreaser, DuPont™ Vertrel® SDG, or Bromothane R. These are highly polar, extremely dense solvents. They will flush the contamination away in a manner that aqueous cleaners simply cannot match. See the Product Specifications for details.

Which MicroCare Products Are Used to Remove Water and Water Spots (Solvent Drying)?

Using a MicroCare cleaner to remove excess water after an aqueous or semi-aqueous pre-cleaning process is a great “one-two” punch. This is technically called “solvent drying.” If there is only a small amount of water to remove, DuPont™ Vertel® XP or MicroCare® CFIPA are good choices. Drying with these types of products is called absorption drying because the polar components in these products absorb the water on the parts. For applications with large amounts of water, DuPont Vertrel® XDA/XFA is an excellent combination. These products are used in a process called displacement drying.  The additives in these products cause water to bead up and float to the surface of the immersion sump. See the Product Specifications for details; also visit the Learning Center.

Which MicroCare Products Should I Use to Deposit Coatings or Lubricants?

This is another application that showcases the versatility of the MicroCare products. When components are dipped into the bath containing the coating, diluted in the MicroCare fluid, the coating goes on smoothly and evenly across the surface on the part. Drips and runs are minimized because the MicroCare fluids evaporate quickly as the part is removed from the bath. It’s a fast, simple and highly effective process.

MicroCare CF is the most commonly used carrier agent for PTFE coatings because both PTFE and the MicroCare fluids are based on fluorine, so they work well together. The Bromothane fluids are better for silicone coatings and lubricants and can be dissolved in concentrations up to 15% or so. See the Product Specifications for details.

MicroCare produces a family of PTFE coatings pre-mixed and ready-for-use. These are marketed under the "DuraGlide™" name. For more details, visit the MicroCare Medical web site.

Are the MicroCare Cleaning Fluids Mil-Spec Approved?

Many of the MicroCare cleaners are used on newer military applications but not for the very oldest mil specs. In the 1990s the military, in conjunction with the I.P.C., developed MIL-STD-2000 as a performance-based cleaning specification for military applications. In effect, MIL-STD-2000 allowed the manufacturer to use any solvent they wanted provided the manufacturer could prove the new cleaning method was at least as good as the old cleaning method. Today, virtually all cleaning is done to these new standards (with the exception of a very few old military and nuclear projects). Contact MicroCare for more details.

Which Cleaner Is Best in a Hand-Wiping Application, to Remove Oil and Grease from Metal Parts?

For hand-dipping or hand-wiping application, use MicroCare HDS precision degreaser. Many MicroCare cleaners also are available in aerosol and pump sprays; visit the MicroCare web site for details on those products. In general, the Bromothane solvents are not suitable for hand-wipe applications because the worker exposure would jump far over the recommended safety level of 10 ppm.

Can I Get MicroCare Products in Aerosol Sprays?

Usually, yes. MicroCare packages a wide variety of the cleaning fluids into aerosol packages. For more details about the specific products and where their applications, visit the MicroCare web site.

However, MicroCare feels strongly that while the Bromothane family of cleaners are very safe when properly used in engineered systems which minimize worker exposures, aerosols are prone to abuse and will subject workers to exposures in excess of the recommended Bromothane exposure limits of 10 ppm. So the Bromothane cleaners are not available in aerosol.

Can I Get a Custom Blend or Customized Packaging of the precision cleaning products?

Absolutely.  There are many different blends and mixtures of the MicroCare cleaners and the Bromothane in the MicroCare labs. Many are just sitting on the shelf waiting for the right application. We have a wide array of options already on the market (which will save you money) but if you need something extra special we have a proven track record of delivering custom blends, as well. Contact MicroCare for details.

Health & Safety Issues

What is the Toxicity Rating for the Precision Cleaning Fluids?

All the MicroCare cleaners have their toxicity ratings listed prominently on the MSDS sheets.  In general, the MicroCare cleaning products and the Dupont Vertrel® specialty fluids can be considered very safe for workers and relatively “non-toxic.” The Bromothane cleaners do have some special toxicity concerns and MicroCare has implemented a strong product stewardship program to manage those.

Specifically, DuPont has set the Threshold Limit Values (TLV) for the Vertrel® fluids to be around 200 parts per million (ppm) which is considered very safe. MicroCare uses similar ratings for the MicroCare-branded materials. All of the Bromothane products are classed at 10 parts per million.

The Threshold Limit Value (TLV) of 10 ppm for the Bromothane solvents is much lower than the ratings some companies use. MicroCare uses the Threshold Limit Value (TLV) for nPB that was established by the American Conference of Industrial Hygienists (ACGIH). This TLV applies to the Bromothane brand solvents sold by MicroCare and to all other versions on nPB marketed by other companies under other brand names.

The decision on the TLV of nPB was not without controversy. Other companies had urged higher threshold levels, as high as several hundred ppm.  But MicroCare feels strongly that the ACGIH decision is the best standard to use.

For more details, see the Learning Center.

How Can I Monitor the Vapors from the Cleaning Fluids?

The vapors from the MicroCare cleaners are generally not hazardous, but monitoring the vapors is an important part of a company’s worker safety program. MicroCare requires an annual air quality monitoring program as part of the Bromothane product stewardship program. All Bromothane users are required to conduct a simple workplace exposure test using air monitoring badges to assure worker safety. This is an excellent process and is applicable to the other MicroCare cleaners besides just the Bromothane products.

The exposures badges are an easy way for the employee to determine the exposure to a chemical. While wearing the badge on the collar of their shirt, each employee simply goes about their daily routine. After wearing the badge for eight hours, the badge is sent to an independent lab to determine exposure levels.

Is It Safe to Heat These Cleaners? Does the Solvent Break Down Under Heat?

Yes, it is safe to heat the MicroCare cleaners, the Dupont Vertrel® products and the Bromothane cleaning agents. In fact, they are designed for it!

First, these cleaning products have no flashpoint and are nonflammable. In addition, they are extremely stable. This means that under normal conditions during storage and use the products will not deteriorate in any way.

Lastly, these products are all true azeotropes or near-azeotropic blends which retain their proportions across all the normal temperature ranges, even when distilled. This specific feature makes them ideal for use in heated cleaning systems, and especially in vapor degreasers.

For more details, see the Learning Center.

Are the MicroCare Cleaners Flammable?

The simple answer is no, none of the MicroCare precision cleaners are flammable. All of these products are nonflammable azeotropes or nonflammable near-azeotropes. Specifically, none of the the MicroCare precision cleaners exhibit a tag closed cup flash point. The products are rated as nonflammable according to the Tag Closed Cup Method ( ASTM-D-56). Because of these test results, none of the solvents are classified as flammable liquids by either the National Fire Protection Association (NFPA) or the Department of Transportation (DOT). For further details, check the Product Specification and/or the Safety Data Sheet for the specific product.

(SPECIAL NOTE: Vertrel® XSi and the BromoBooster concentrate are flammable mixtures. These two products need to be handled with all the normal care and caution used on any flammable material, such as isopropyl alcohol. See the Product Specifications for details.)

What Kind of Safety Gear Should I Use With the MicroCare Cleaners?

Skin and eye contact are the most common risks. Impervious gloves and protective clothing are the best choice if there is any potential for skin contact. Gloves, splash goggles, aprons (when handling open drums), and safety shoes with steel toes are highly recommended.

MicroCare recommends gloves made of butyl rubber or other materials to provide optimal protection; Viton® gloves also work adequately. Chose the powderless option if it is important to control nonvolatile residues in your production process. These are widely available from quality distributors everywhere.

What Steps Should Be Taken to Work Safely with MicroCare Cleaning Fluids in Enclosed Areas?

Vapor degreasers filled with the MicroCare cleaners are very safe cleaning systems. However, during maintenance technicians may be exposed to unusually high concentrations of vapors. Users should be aware that solvent vapors are four to eight times heavier than air. These heavy vapors will displace the air in a confined space. In the event of a spill, and before attempting any remediation or control measures, evacuate the area and thoroughly ventilate the work spaces.

If there is any concern that a very high concentration of vapors may exist (such as during a spill) supervisors should follow the safety regulations specified by O.S.H.A. in the U.S. Code of Federal Regulations CFR 29 for safe tank entry procedures. Contact your company’s Health and Safety manager or O.S.H.A. for details on these specifications.

To ventilate a confined area, use fans to force air down to the lowest point in the area. Monitor the composition of the atmosphere in the area. Before it will be safe to enter the area safely without an independent air supply, the oxygen content should be at least 18.5% and the concentration of solvent vapors should be below the AEL for the solvent in use.

Regulatory Issues

How Do I Ship the MicroCare Cleaners? How Do I Dispose of Them?  What Are the RCRA Classifications?

Because the MicroCare cleaners are nonflammable and non-corrosive, they are not regulated as hazardous materials by the Department of Transportation. Even though some cleaning agents are mixtures that include other solvents such as alcohol, none of the mixtures are classified as flammable, poisonous or corrosive by the friendly folks at the D.O.T. They all are shipped under the classification of “Non-Regulated/Non-Hazardous.”

(SPECIAL NOTE: The BromoBooster stabilizer concentrate and the Vertrel® XSi are flammable and are regarded as a hazardous for transportation purposes. From a practical point of view, this is only critical if you are shipping the material by air. For normal ground transportation, it’s mostly a paperwork issue.)

As for disposal, the same rules would apply unless the user has introduced a RCRA hazardous material during use. Users should test the exhausted product to ensure proper RCRA classification for waste disposal and should check local, state, and federal requirements in determining disposition of spent product. Most spent solvent is incinerated in cement kilns; typically that service costs $150 per drum. Contact your hazmat disposal service for details; normally they will require a chemical analysis of the material to determine the exact chipping classification.

Are the MicroCare Cleaning Fluids S.N.A.P. Approved and Accepted?

Yes. All of the MicroCare cleaning fluids products and their ingredients have been reviewed under the Significant New Alternatives Program at the U.S. Department of Environmental Protection. The E.P.A. has made it’s final ruling and approved these cleaners for the marketplace. The approval for nPB (the Bromothane cleaners) is restricted to the metal finishing industry, electronics manufacturing and precision cleaning, but all other products have approvals that are unrestricted.

Are the MicroCare Cleaning Fluids F.D.A. Approved?

No, the MicroCare cleaning fluids are not themselves approved by the U.S. Food and Drug Administration.  The F.D.A. approves products that are marketed as medicines and have proven medicinal benefits, or are part of machines, tools or systems used in medical procedures. It is perfectly acceptable to use the MicroCare cleaning fluids on medical products for cleaning and surface preparation because the solvents evaporate completely and leave no residues. The manufacturer needs to document the cleaning process and may need specific approvals from the F.D.A.