Hakidashimado

I came across an article on Bioplastics News[1] about a new process from VTT (Finland) to produce lignin substitute for phenol in phenol-formaldehyde adhesives. This is a great development, and should help as we find substitutes for petroleum-based products. However, the article contains an inaccuracy that, like many other well-meaning articles, continues to lead people to think certain chemicals are categorically bad. It is a pet peeve of mine, because often, the simplistic “solutions” can be worse than the “problem”, and in the big picture, take away useful options for a sustainable future—without needing to.

In the article, they say:

Traditionally phenol and formaldehyde containing adhesives are used in wood products such as plywood, laminated veneer lumber, particle wood panels and laminates. There is a strong legal drive from sanitary authorities in Canada the US and the EU towards more stringent limitations up to a complete ban of phenol formaldehyde (PF) adhesives in wood panels. The reasons is that they are actually releasing formol for years after manufacturing.

The push by various “sanitary” (?) authorities is to eliminate the use of UREA-formaldehyde resins since the reaction that polymerizes (cures) the adhesive is REVERSIBLE under high humidity and temperature conditions. The PHENOL-formaldehyde reaction is not reversible. (And, the only real relationship observed between formaldehyde and cancer is a slightly elevated rate of nasopharyngeal cancer in people who work with the material-so it is listed as “suspected”, but hey, let’s not let a lack of evidence stop us from responding to hysteria).

Several things to be aware of: -if the manufacturer uses poorly formulated resin, there can be excess formaldehyde that is released. -urea-formaldehyde resin in US wood panel factories is generally used as a premixed product from a large adhesive supplier, made with the least amount of formaldehyde needed to cure the adhesive, and tested to meet a number of industry and government standards -urea-formaldehyde resin in factories overseas is often mixed in the factory to save cost, by workers with variable levels of education, and may or may not be tested to meet a standard. When you purchase your inexpensive particleboard products, please think about news reports of imported products where foreign government officials had been bribed to pass untested materials that were later found to be hazardous. There are more reasons than labor costs that US-Canadian-EU products cost more. -In the EU, the particleboard is often made with isocyanate adhesives. When properly made and cured, the only formaldehyde emitted comes from the wood when it is hot-pressed, and that dissipates within days of manufacture. Uncured adhesive reacts with moisture in the wood to completely cure it. However, manufacturing the adhesive uses isocyanates; the Bhopal, India industrial accident injured and killed thousands of people surrounding the plant. For workers, isocyanate is toxic at much lower levels than formaldehyde (OSHA permissible exposure limits are 0.02 ppm for isocyanate vs 0.75 ppm for formaldehyde).

Of all the wood adhesives, phenol-formaldehyde gives superior bonding and product durability in wet or dry conditions. It is better than epoxy, pMDI, acrylics, both in bond strength and wet durability, and It allows the use of small diameter forest thinnings as useful products, sequestering carbon dioxide for the (longer) lifetime of the product. Using small diameter material improves forest health, reduces wildfire risk, and by thinning, an uneven age management strategy benefits wildlife and watersheds while helping forest land owners afford to keep the land in forest.

There is no perfect technology or manufacturing method. Taking away this useful and durable adhesive reduces the choices to adhesives which have shorter lifespans, less resistance to moisture and shorter time for CO2 sequestered, or higher potential for harm in the event of accidental release.

[1] https://bioplasticsnews.com/2017/03/06/vtt-finland-develops-catlignin-a-reactive-lignin-for-wood-adhesives/ [2] https://en.wikipedia.org/wiki/Bhopal_disaster