The recent European provisions on diisocyanates, will importantly affect also the wood and furniture sector considering the variety of raw materials which can contain such dangerous chemicals. With this short article we would like to briefly remember what these substances are, where they can be found and what are the potential risks associated with their use.
What are diisocyanates and what are they used for?
Diisocyanates are a particular group of chemical substances characterized by high reactivity with other substances to generate new compounds.
The reactivity of diisocyanates is actually double (the prefix "di" precisely indicates this dual functionality). In this way a diisocyanate molecule can then bind simultaneously to two molecules of other substances to generate molecular aggregates which can become very large and complex when the reactivity of the other substances with which it reacts is also double or higher.
The most common diisocyanates are toluene diisocyanate (TDI), methylene bisphenyl isocyanate (MDI) and hexamethylenediisocyanate (HDI) which are widely used especially in the production of polyurethane derivatives such as: foams, plastics, adhesives, coatings and primers for various applications.
In reality, many of these materials have been made with diisocyanates as basic ingredients, but the final product, i.e. the adhesive, the coating, etc., no longer contains them, since these chemical species have completely reacted with the other substances that were used to produce them.
However, there are exceptions that specifically concern some products that maintain their chemical reactivity when used. In particular we are talking about: some types of hardeners for coatings and adhesives (often called catalysts), the hot-melt polyurethane adhesives used in edging or lamination processes, the single-component polyurethane adhesives for the parquet laying and some types of primers sometimes classified as moisture-curing.
Given their high chemical reactivity,
free diisocyanates have always been under the attention of occupational hygiene bodies for the negative effects they can cause when they penetrate the human body.
But what are these effects?
What does the recent European restriction in force since 24 August 2023 stipulate?
Continue reading,
by clicking here...
For info:
Franco Bulian
+039 0432 747231
bulian@catas.com
