Additives for fluoroelastomers
Fluoran UR: coated calcium hydroxide, high purity and ultrafine particle size, developed by De Grandi for the curing of fluoroelastomers.
The data sheet
Fluoran UR is a high-purity coated calcium hydroxide developed by De Grandi for the compounding of fluoroelastomers. It combines extreme chemical purity and an ultrafine particle size distribution with a specialised hydrophobic coating, the product of surface-treated powder technology.
It is a white powder and an essential inorganic component in FKM vulcanisation, where it plays a decisive role in achieving optimal physical properties and ensuring process stability.
How it acts
In fluoroelastomer curing Fluoran UR performs a dual function: it is an inorganic activator and, at the same time, an acid acceptor. It neutralises the acidic species that develop during vulcanisation and helps to regulate the curing process.
Both the stability of the process and the physical properties of the vulcanisate depend on this dual action: consistent curing rates, thermal stability and mechanical integrity of the finished compound.
Why it matters
Fluoran UR differs from standard calcium hydroxide on three fronts, all of them connected to consistency of results in production.
Acid acceptorIt is non-hygroscopic: standard calcium hydroxide attracts moisture and degrades, while Fluoran UR remains stable over time, even in humid environments.
A strictly controlled particle profile: 0% above 80 μm and 0.5% above 43 μm, for optimal reactivity.
High active content and minimal impurities: maximum performance as an acid scavenger.
Repeatable curing rates from batch to batch.
Enhances the thermal stability of the vulcanisate.
Contributes to the final mechanical properties of the compound.
Supply
Fluoran UR is available in 20 kg paper bags with an inner polyethylene bag, and in 500 kg big bags. The declared shelf life is 24 months.
The non-hygroscopic nature of the product is what makes this storage life possible: an untreated calcium hydroxide in contact with ambient moisture would lose effectiveness far sooner.
FAQ
Fluoran UR is the high-purity coated calcium hydroxide produced by De Grandi for the compounding of fluoroelastomers (FKM). It is a white powder combining high chemical purity, an ultrafine particle size distribution and a specialised hydrophobic coating. In the compound it acts both as an inorganic activator and as an acid acceptor.
It performs a dual function: it neutralises the acidic species that develop during vulcanisation, acting as an acid acceptor, and it helps to regulate the curing process as an inorganic activator. Process stability and the final physical properties of the vulcanisate both depend on this action.
For three reasons. It is non-hygroscopic: while standard calcium hydroxide attracts moisture and degrades, Fluoran UR remains stable over time even in humid environments. It has an ultrafine, controlled particle size, with 0% of particles above 80 microns, ensuring optimal reactivity. And it has high purity, with high active content and minimal impurities, for maximum performance as an acid scavenger.
The particle profile is strictly controlled: no particles above 80 microns (0%) and only 0.5% above 43 microns. This fineness ensures optimal reactivity and uniform dispersion in the FKM compound.
Fluoran UR is available in 20 kg paper bags with an inner polyethylene bag and in 500 kg big bags. The declared shelf life is 24 months, made possible by the non-hygroscopic nature of the product.
Fluoran UR is produced by De Grandi at its plant in Tromello, in the province of Pavia, Italy. For enquiries, samples and technical documentation you can contact the company on +39 0382 868402 or at info@degrandisrl.it.
