Fire-retardant and smoke-suppressant rigid polyurethane foam composites

Abstract

Purpose The purpose of this paper is the production of fire retardant and smoke suppressant rigid polyurethane foam (RPUF) with lower toxicity by using several fire-retardant combinations. Design/methodology/approach Fire-retardant additives with cooling effect, barrier ash formation effect, gas-phase inhibition effect and smoke suppressant effect combined to produce an optimum outcome on RPUF. The additive amount and burning time correlation were studied to find out the minimum amount of fire-retardant to obtain fire-retardant polyurethane foam. Findings Zinc borate powder was coated with 1.5 wt % of stearic acid and hydroxy stearic acid. Polyammonium diborates (PABs) were synthesized and used as a fire-retardant and smoke suppressant for rigid PU foam. Fire-retardant rigid polyurethane foams (FR-RPUF) composites formed by using several combinations of zinc borate, aluminum trihydroxide, trischloroisopropyl phosphate (TCPP), PABs, zinc borate coated with stearic acid and hydroxy stearic acid. Produced FR-RPUF were horizontal burning grade, and burning time was in the range of 1–10 s. Research limitations/implications There were limitations during the mixing of fire-retardant powders with polyol due to the high viscosity of the mixture. Practical implications FR-RPUF foam with lower toxicity can be produced industrially with these fire-retardant combinations. Social implications FR-RPUF could be produced by using non-toxic additives. During a fire, these additives do not evolve toxic gases. The TCPP content of RPUF foam was reduced, and fire-retardant PU with lower toxicity was produced. Originality/value Coated zinc borate and the combinations of the fire-retardants were successful in producing non-toxic fire-retardant and smoke suppressant PU foam.

Smoke suppressant and fire‐retardant polyurethane‐polyisocyanurate (PIR) foam

“…Inorganic fillers 28 and combustion modifiers 4 affect the density of PIR foam during the formation. Solid additive particles may act as heterogeneous nucleation sites, reducing the size of foam cells and increasing density 29 .…”

“…Unfortunately, it diffuses out of PUF to the environment and causes health problems. It is possible to reduce the amount of TCPP in the formulations when used together with other non‐toxic fire retardants in rigid PU formulations 4 . Another way of reducing the diffusion of TCPP out of PUF during usage is its microencapsulation with melamine‐formaldehyde 5 …”

“…Zinc borate is a well‐known smoke suppressant and contributes to a certain extent to fire retardancy. The ATH and Zinc borate mixtures in RPUF result in fire‐retardant and smoke‐suppressant foam 4,9 …”

“…It is possible to reduce the amount of TCPP in the formulations when used together with other non-toxic fire retardants in rigid PU formulations. 4 Another way of reducing the diffusion of TCPP out of PUF during usage is its microencapsulation with melamine-formaldehyde. 5 Inorganic fire-retardant compounds such as ammonium polyphosphate, 6 melamine phosphate, 7 melamine borate, 8 zinc borate, 9 and nanoclay 10 are also non-toxic fire-retardant for PUF.…”

“…The ATH and Zinc borate mixtures in RPUF result in fire-retardant and smoke-suppressant foam. 4,9 PIR (PU-PIR) foam contains both polyurethane and polyisocyanurate groups. PIR foam is especially preferred in the construction industry due to its high stability, superior thermal resistance, and dimensional stability.…”