Advantages of Fluorinated Solvents Over Aqueous Cleaning

cleaning solder flux with fluorinated cleaning solvents

Reading Time: 4 minutes

For many industries like medical device, aerospace and automotive, parts and components be cleaned and degreased before they are assembled or shipped. While many cleaning solutions exist on the market, regulations for cleaning chemicals are becoming more stringent.

The United States is committed to implementing the Montreal Protocol on Substances that Deplete the Ozone Layer that requires many manufacturers to use more environmentally sustainable cleaning solutions like fluorinated solvents or aqueous cleaning.

Both these cleaning methods can help manufacturers reduce their use of unfavorable chemicals while effectively cleaning parts.   Each has different advantages and disadvantages that should be carefully considered before selecting one to clean your substrates or fit into your facility processes.

What are Fluorinated Solvents?

Fluorinated solvents, or fluorosolvents, are high-performance chemicals that clean dirt, oil, fingerprints, solder paste residue, electronics flux, and other contaminants from high-value parts and components.

Fluorosolvents are regarded as environmentally sensible because they have:

  • No flash point
  • No ozone depletion potential (ODP)
  • Low global warming potential (LGWP)
  • Low surface tension
  • Nonexplosive and nonflammable
  • Stability and can be recycled

Because of their low surface tension, fluorosolvents better penetrate the surface of a contaminant while being gentle. Substrates including metals, plastics, polyurethanes and fluoroelastomers can be effectively cleaned using with fluorinated cleaning solvents.

What is Aqueous Cleaning?

Aqueous cleaners use water as the primary solvent along with other cleaning agents. As water alone is not usually powerful enough to break down contaminants, it must be combined with additives such as surfactants, detergents, emulsifiers, inhibitors, anti-foaming agents, pH buffers, builders, deflocculants or chelating agents.

Depending on the type of substrate and contaminants, the water also may be treated to become more acidic or alkaline to work effectively. Acidic aqueous solutions are more effective at removing contaminants like scale, rust, and oxides from metal. Alternatively, alkaline aqueous solutions are better at removing salts, oxides, organic soils, metal chips and grease. In addition, alkaline aqueous solutions can be used at a wider range of temperatures than acidic solutions.

Soaking in water, even water with added chemicals, is not typically effective for removing contaminants on high-value parts. That’s because aqueous cleaning systems also must employ heat, agitation or pressure spray to effectively clean intricate parts or hard-to-remove contaminants.

Cost Savings with Fluorinated Cleaning Solvents

Although fluorinated solvents may cost more per pound, some studies show that aqueous systems increase total system costs by 30% by using water.  In addition, aqueous equipment is large, expensive and may require a significant reconfiguration of space to install in your facility. Fluorosolvents use a vapor degreaser, which requires less space and energy due to shorter cleaning and drying cycles.

Aqueous systems do not dry parts on their own and require post-processes like infrared drying, which consume additional energy and manpower. They are also known to leave water spots, so you must use deionization or reverse osmosis processes to avoid them. Fluorosolvents do not leave water spots or residue so the cleaning method doesn’t require additional processes.

When using aqueous cleaning, heating water is a critical step to ensure parts and components are fully cleaned. While fluorosolvents also require heat, their boiling point is significantly lower than water, requiring less energy usage and time. Aqueous systems must also be carefully monitored during the cleaning cycle to ensure that the water level, pH and soap concentration stay at the correct levels.

Fluorinated solvents are exceptionally stable and can be reused over and over again, giving them a lower cost per use. Aqueous cleaners, on the other hand, come with additional costs to reclaim and recycle water or manage waste oil. The table below shows a comparison of the properties of these two cleaning methods.

Properties of Fluorinated Solvents vs. Aqueous Cleaning

Fluorinated Solvents Aqueous Cleaning
Cleaning formula Single cleaning fluid or a custom blend to remove specific contaminants. Additives and compounds added to water can include detergents, surfactants, and buffers.
Sustainability New cleaning fluids are more sustainable with low GWP and zero ODP; exceptional stability. of solvents means they can be reused and recycled without losing effectiveness. Additives can range from very mild, non-toxic to very strong and dangerous.
Energy Demand Parts dry on their own. Energy required for pre-treating, heating cleaning water and drying parts.
Part Geometry Complex such as small, intricate steel parts with tiny holes. Simple parts.
Footprint Cleaning conducted in a single machine in one step Three-step process requires multiple wash stations, rinsing baths and heaters extends footprint
 Post-Cleaning Results Leaves no residue or spots Leave spots or stains: must use deionization or reverse osmosis processes to avoid them.
Cleaning Time 10 minutes as parts are cleaned in a one-step process Up to 30 minutes as parts move through multiple cleaning stations
Ideal contaminants for removal Nonpolar contaminants: halogenated, oxygenated and hydrocarbon soils such as machine oil, grease, and fingerprints. Polar or inorganic contaminants including salt, soap and rust.

 

Applications

The goal of using specific cleaning processes is to clean parts at lowest cost while safeguarding the environment and worker safety. Fluorinated solvents are compatible with a wide range of materials and can be used with most plastics, elastomers, metals and substrates.  They are ideal for removing fingerprints, electronics flux, oil, grease and other contaminants from high-value and complex parts.  They provide exact cleaning for most precision applications.

As some cleaning agents added to aqueous solvents are very strong, they can react aggressively to some metals, plastics and other materials.  Prior to cleaning, parts must be tested for compatibility and post clean tested to ensure no reactive material is left behind.  After cleaning, wastewater must be treated for disposal.  Aqueous solvents are mostly ideal for removing inorganic contaminants such as salt, soap, rust and other oxidation.  It also works well when combined with other cleaning processes like rust preventers and brighteners.

AsahiKlin Fluorinated Solvents

AGC created the AsahiKlin AE-3000 series of fluorinated solvents as an environmentally sensible solution to replace halogenated solvents with unfavorable environmental properties. AE-3000 solvents are approved for use as:

  • Precision cleaning solvents
  • Defluxing agents for electronic circuitry
  • Carrier solvents for silicone
  • Fluorinated lubricants and moisture displacement fluids

They can also be used in most existing vapor degreasing equipment with little or no modification, eliminating the need for costly equipment conversions or additions. To learn how you can incorporate AsahiKlin fluorinated cleaning solvents, contact an AGC product expert.

AGC Chemicals