Romans, France -- Manufacturers of polyurethane hot-cast elastomers used to have to perform a delicate balancing act, according to French expert Baule. If they choose to use methylene diphenyl diisocyanate (MDI) as a raw material, "they must be extremely careful to observe processing parameters such as product temperatures, mould temperatures and machine settings with meticulous accuracy," the Romans-based group said.
But if they opt for toluene diisocyanate (TDI) prepolymers, with their broad range of processing options, they have to take ensure they do not exceed the maximum concentration of TDI permitted at the workplace.
Baytec MAX, a new generation of amine-crosslinked prepolymers, now offers a way out of this dilemma. Developed by Bayer MaterialScience and Baule, it contains no TDI whatsoever, yet it remains easy to process.
Baule, which will tell Chinese customers about the development in a presentation on Thurs 8 Sept at 2.00 pm at the UTECH Asia/PU China 2011 event in Shanghai, says this technology is more than just an alternative to TDI prepolymers and prepolymers with low-free-TDI content of less than 0.1 percent. "Instead, this range of products is an innovation that provides manufacturers with a safe, easy method of producing polyurethane cast elastomers with an altogether superior range of properties," the company claims.
Tests by Baule have revealed that the resulting polyurethane elastomers possess excellent mechanical properties and also have exceptional abrasion resistance and hydrolytic stability.
Common aromatic amines such as MOCA (2,2' dichloro-4,4'-methylene dianiline) are suitable as crosslinking agents for the Baytec MAX system. Tests have shown that Baytec XL1705 is an appropriate curative, perfectly-priced option for processors who want to have a TDI and MOCA free system.
Polyurethane elastomers based on the new MDI prepolymers "demonstrate outstanding mechanical properties such as high elongation and excellent tear and tear propagation resistance.
In this respect, even very soft systems are far superior to their conventional counterparts," the company observes.