Clariant says its halogen-free flame retardants can lock in fire protection for renewable polyurethane foams

Urethanes Technology International reported how Polyurethane foams with permanent flame retardants offer a novel way to pass the well-respected Cal 117 flammability standard earlier this year in a paper which discussed how manufacturers can use reactive halogen-free flame retardant Exolit OP 560. This is a reactive polyol with an hydroxyl value of around 450. The paper showed how this technology can be used  to develop low emission flexible foams that meet internationally accepted flammability standards such as Cal TB 117 (California Technical Bulletin 117, a flammability test for upholstered furniture using a small flame).

In the furniture and bedding industries, large quantities of non-reactive flame retardants are traditionally used to achieve flame resistance for flexible foams. These flame retardants, which are merely physically mixed into the foam, can migrate out of the foam matrix and are associated with adverse environmental and health consequences.

“Clariant’s Exolit OP 560 phosphonate liquid flame retardant addresses these concerns by eliminating unwanted emissions. The grade chemically reacts into the PU foam polymer and therefore does not migrate and remains fixed within a foam formulation, also resulting in reduced amounts of volatile organic compounds (VOCs),” said Adrian Beard, Clariant’s head of marketing for flame retardants.

According to the company, the phosphonate’s effectiveness and high polymer compatibility allows it to be used at low dosage in the foam matrix, which adds to its overall sustainability. By applying Green Urethanes’ unique processing characteristics, the amount of flame retardant required for flexible foam to pass the smolder and open flame tests in California TB 117 is reduced by 80%.

The company said the product can further benefit PU applications due to its ageing stability, low smoke density and smoke gas corrosivity as well as recyclability.


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