MDI and Worker Safety

MDI and Worker Safety

I read with interest your July/August issue (Vol. 6, No. 7). I was particularly drawn to your article on Louisiana-Pacific’s new siding line, SmartStart.

While you were accurate in noting that MDI binder is more resistant to moisture and swelling than the competitors’ resin, I would like to comment on your portrayal of MDI as “more hazardous than other common binders at the manufacturing stage.” I am a representative of ICI, the company that supplies Rubinate® binder (a brandname for MDI and trademark of ICI Americas Inc.) for LP’s SmartStart panels.

MDI is a chemical that has been used for more than 40 years for various commercial purposes. It is used to produce polyurethane foam insulation that keeps our homes warm, our refrigerators cool, as well as in bedding and car seats. MDI is also a bonding agent used in wood composites such as Oriented Strand Board (OSB). In fact, almost 50% of North American mills making OSB use MDI binder, many of them Rubinate binder from ICI.

In addition to MDI, the other type of resin commonly used to manufacture OSB is phenol formaldehyde (PF). As with any chemical, such as gasoline or a household cleaner, special safety handling and use measures must be followed when using both MDI and PF resins. Instructing our customers and their workers on the safe and proper handling of Rubinate binder is and has been a high priority of ICI.

Of course, questions always arise about the safe use of chemicals. Rubinate has been extensively tested and used in the OSB industry for years. In fact, our customers using Rubinate binder have shown it can be safely controlled in the mill. Monitoring the work area where Rubinate is used and implementing the appropriate engineering controls and personal protective equipment further safeguard the work environment.

It should be noted that Rubinate binder provides numerous important benefits. Because Rubinate binder actually reacts with moisture present in wood, using it instead of formaldehyde binder resins can allow mill dryers to operate at lower temperatures resulting in reduced VOC emissions from the process. Due to the unique binding chemistry of Rubinate binder, it may be possible to produce high quality wood composites such as OSB at reduced densities, using less wood and extending the natural resource. Additionally, Rubinate binder contains no formaldehyde and therefore does not add to the formaldehyde emissions already being released naturally from the wood itself.

C. John Galbraith

Business Manager

ICI Polyurethanes

West Deptford, New Jersey

From the Editors:

We appreciate the advantages of MDI binders and your comment that all chemicals must be handled appropriately. However, we stand by our statement that MDI is more hazardous to factory workers than PF resins. In fact, we were informed of worker health problems from exposure to MDI at Trus-Joist MacMillan’s TimberStrand facility in Deerwood, Minnesota.