Cleaning Agents for Cured and Uncured Urethane

 

 

The following is some information on the cleaning agents for cleaning urethanes.  We do not carry these materials.  The recommended suppliers’ links are at the end of the document.  Please contact the suppliers directly.  Many cleaning agents have high volatility and are flammable.  Please consult your supplier for the safety and handling information.

  

Methyl Ethyl Ketone (MEK)

 

This can be used as a general cleaning material to clean tools, molds, and machine.  Acetone can be used as a cleaning agent, but since MEK has slower vaporizing rate, MEK is easier to use than Acetone.  MEK is still volatile and flammable. You have to be very careful handling this material.  Make sure you use this in a well-ventilated area.

 

Dibasic Ester (DBE)

 

This has low vapor rate than MEK, and it is not considered to be flammable.  (It is still combustible, which is same flammability as the paint thinner.)  You can use this to soak your lines, machines, and tools.  This material swells the solidified urethane material and makes it very soft, so it is easier to remove.  Since this does not vaporize quickly, small residual will be left in your line and machines or mold.  You may use MEK or your production resin raw material (polyol or isocyanate whichever is used in the line) to flush the small left over after DBE is used. In this way, you can limit the amount of MEK you use to reduce the fire hazard.

 

N-Methyl Pyrrolidone (NMP)

 

If DBE is not strong enough, you can look at NMP.  Like DBE, NMP has a low vapor rate.  This has stronger solvency than DBE, so it can break down more persistent urethane stuck in your mold, lines, and parts.  However, the toxicity level of this material is higher than DBE.  So, if DBE works well for most of the parts, you probably want to stay with DBE.  You would probably want to try limiting the use of NMP if possible.  Again, this does not vaporize away; so you need to flush with MEK or your production resin raw materials to clean.

 

Other Information

 

Small amount of these cleaning agents should not affect overall properties of your polyurethane product.  However, these cleaning agents sometimes contain high concentration of water.  Lower the water concentration better it is.  Ideally, water concentration should be lower than 0.3% in the cleaning solvent.  If it contains high amount of water in your cleaning agent, be sure to dry the cleaning agent completely before you start your production.

 

Alcohol cleaning agent can clean urethane off as well.  However, alcohol reacts with isocyanate component in the part-A material, and it will affect the quality of your product.  Avoid using alcohol cleaning agent where you cannot be sure it is completely dried. 

 

Aliphatic hydrocarbon materials such as mineral spirits or paint thinner do not clean polyurethane.  Aromatic hydrocarbon such as Aromatic 160 can clean polyurethane.  If the odor is not a problem, you may use aromatic hydrocarbon for cleaning.

 

If you prefer to keep the lines of the machine filled with liquid material while the machine is idle for an extended period, DBE may not be a good choice, because it can solidify from residual material or may affect rubber and plastic parts (gaskets and hoses) on your casting equipment.  If you want to keep liquid inside the lines for an extended period of time, we recommend using mineral seal oil.  Mineral seal oil is less invasive to rubber and plastic parts, and fairly easy to handle.

 

 

Source Information

 

You may obtain these cleaning agents from the following sources.  Please check with these suppliers for your local sources.

 

 

Ashland Distributions

http://www.ashland.com/

  

Brenntag

http://www.brenntagnorthamerica.com/en/pages/companyProfile/index.html

  

Univar

http://www.univarusa.com/

 

 

 

 

 

For any questions, please contact Northstar Polymers.

 

Northstar Polymers, LLC

3444 Dight Avenue South

Minneapolis, MN 55406

Tel: 612.721.2911

Fax: 612.721.1009

E-mail: info@northstarpolmers.com

 

 

 

 

 

 

 

 

Revised: April 8, 2011