Advances in Low-Density Flexible Polyurethane Foams by Optimized Incorporation of High Amount of Recycled Polyol

Abstract

An industrially manufactured recycled polyol, obtained by acidolysis process, was for the first time proved to be a possible replacement of the reference fossil-based polyol in a low-density formulation suitable for industrial production of flexible polyurethane foams. The influence of increasing recycled polyol amounts on the properties of the polyurethane foam has been studied, also performing foam emission tests to evaluate the environmental impact. Using 10 pbw recycled polyol in the standard formulation, significant differences of the physical properties were not observed, but increase of the recycled polyol amount to 30 pbw led to a dramatic decrease of the foam air flow and a very tight foam. To overcome this drawback, N,N′-bis[3-(dimethylamino)propyl]urea was selected as tertiary amine catalyst, enabling the preservation of foam properties even at high recycled polyol level (30 pbw). Foam emission data demonstrated that this optimized foam formulation also led to an important reduction of volatile organic compounds. The results open the way for further optimization studies in low-density flexible polyurethane foam formulations, to increase the reutilization of the polyurethane waste and reduce the amount of petroleum-based raw materials.

Insight into Chemical Recycling of Flexible Polyurethane Foams by Acidolysis

“… 25 The increasing deformation of PUFs with increasing RP content in the formulations was previously attributed to the presence of low-molecular-weight impurities in the polyols, such as amine-terminated aromatic residues of hard segments and/or the glycol reagent in the case of glycolysis, which react with diisocianate and lead to stiffer PUFs enriched with hard segments. 25 , 39 , 40 , 45 , 46 …”

“…For this reason, none of the PUF recycling methods is able to produce high-quality virgin-like polyols that would allow foam manufacturers to produce new flexible PUFs exclusively from the recycled polyol (RP) without compromising their properties. 22 , 23 , 39 , 40 …”

Synthesis of a new bifunctional molecule based on castor oil and CO2 useful for polyurethanes

“…The epoxidized molecule obtained under best epoxidation conditions (Amberlite IR-120 at 8 h) was carbonated with CO 2 at 6 MPa. 1 HNMR spectrum of the product obtained after the carbonation reaction is shown in Figure 5. As shown, the signals at 2.8-3.1 ppm, corresponding to the protons of oxirane ring decreased, while the protons of the cyclic carbonate appeared at 4.39-4.91 ppm.…”

“…The global PU foam market is projected to grow from around 15 million tons in 2020 to 20 million tons in 2025. 1 PU materials have a large number of applications due to their excellent physical and mechanical properties such as elasticity, durability, and abrasive resistance. 2 They are used for the production of elastic and rigid foams, high-performance coatings, seals, and adhesives.…”

“…I G U R E 2 1 HNMR spectrum of ME-RAM F I G U R E 31 HNMR spectrum of the epoxidized ME-RAM using Amberlite IR-120 at 48 C for 8 h…”