MCPU targets TCPP-free PIR foam with soy-based additive

MCPU Polymer Engineering has developed a soy-based reactive additive that it says can replace the halogenated flame retardant TCPP in rigid polyisocyanurate insulation foam without compromising processing or finished-product performance.

The US company will present its results at the CPI Polyurethanes Technical Conference in Orlando, Florida, on 7 October.

In a commercial PIR formulation, 15 parts of conventional polyester polyol were replaced with MCPU’s phosphorylated soy-based additive. The modified foam reportedly matched the flame-retardant performance of the TCPP-containing reference system in DIN 4102 B2 testing.

MCPU said the substitution produced no significant change in thermal resistance, yield stress, density or foam-processing characteristics compared with the fossil-based control.

The work forms part of a materials-development framework that MCPU calls “biocongruent chemistry”. It uses soy-, lignin- or silicone-derived reactive components within established polymer formulations, rather than attempting to replace the entire system with bio-based raw materials.

MCPU said the approach is intended to preserve performance throughout a product’s service life while making the material more susceptible to biological degradation after disposal.

The company also tested a polyurethane carpet-backing formulation in which a blend of its soy additive and a non-halogenated phosphate flame retardant replaced 20 parts of polyol and filler. MCPU said the material matched the flame-spread performance of a Class I-rated commercial carpet.

Soil-burial tests reportedly showed greater mass loss in PIR foams containing soy- and lignin-based polyols than in fully petroleum-based control materials. The modified foams nevertheless retained most of their measured mechanical properties during the test period.

In a separate field trial, soy-modified polyurethane elastomers underwent measurable degradation during 112 days of exposure to wastewater-treatment conditions without what MCPU described as a meaningful loss of mechanical performance.

The company is commercialising the approach for foam, elastomer, adhesive and coating formulations. Its Yellow Jacket additives are designed to replace part of the conventional polyol component and become incorporated into the polymer network.

MCPU developed the underlying research with Gogte Institute of Technology in India, the National Institute for Materials Advancement in Kansas, Purosil and consultancy LCA Design.

The conference paper was written by Saeed Fosshat, Enoch K. Acquah, Xian Xian Du and Thomas M. Garrett of MCPU, Andrew H. Garrett of Purosil and Katie Soulliere of LCA Design.

The full paper and supporting test data have not yet been made publicly available. Detailed information on the biodegradation conditions, mass-loss rates and longer-term effects on foam performance is therefore still to come.

Photo: Soybeans, Yellow Jacket additive and a block of rigid foam © MCPU Polymer Engineering

MCPU Polymer Engineering