Emerox and Infigreen polyols in HR foams

Emery Oleochemicals has introduced Emerox renewable and Infigreen recycled polyols as part of its range of eco-friendly polyols for flexible polyurethanes. These have potential applications in the automotive sector where OEMs are increasingly demanding green alternatives to conventional materials.

Emerox polyols are produced via Emery Oleochemicals’ proprietary ozonolysis technology. InfiGreen polyols are aromatic polyether/ester polyols, produced via our proprietary chemical process that uses scrap polyurethane foam as the key raw material.

In this paper, the performance characteristics of Emerox and Infigreen polyols are demonstrated as a partial drop-in replacement for conventional polyether polyols in resilient TDI-based flexible polyurethane foams. The impacts of Emerox and Infigreen polyols are evaluated on the foaming reaction profiles and on the key physical properties of free-rise and moulded high resilient polyurethane foams.

Introduction

Emery Oleochemicals started working on ozonolysis of fatty acids, with commercial implementation in the 1960’s. Emerox polyols can be produced from several types of natural oils to yield bio-polyols with the possibility of a high level of polyol structure customization and improved consistency over existing natural oil polyols (NOPs). This should enable higher incorporation levels in polyurethane applications.

Automotive consumers are increasingly expecting their cars to be greener, and these renewable or recycled polyurethane foams give benefits in areas of comfort, safety and protection and energy conservation.

Translating these benefits to consumers with better gas mileage and comfort; demand for polyurethane flexible foams alone is set to rise by a compound annual growth rate of 12.2%. This is estimated to generate revenue of $1.1 billion by 2018 for the industry and is the fastest growing applications for green and bio-polyols.

Emerox polyols are renewable NOPs. NOPs, are derived from triglycerides like vegetable oils or natural fats. Except for castor oil, all other natural oils have to be chemically modified to introduce hydroxyl groups to enable them to be used as polyols.

There are several hydroxylation processes available for fatty acids, and most of these processes involve the oxidation of the C=C double bond. However, depending on the source of oil used and inconsistencies in the oils, the properties on NOPs can vastly vary.

Emery Oleochemicals’ process includes ozonolysis of natural oils to produce mono- and di- aliphatic carboxylic acids, which are separated according to their composition. These are then esterified to produce Emerox polyols. This technology enables polyols with a broad range of hydroxyl numbers; with well controlled functionality and molecular structure. Emerox 14001 and Emerox 14055 grades are designed for use in flexible foams.

Infigreen polyols are produced from scrap polyurethane foam using a proprietary two-stage process that uses chemolysis to depolymerize the foam and is followed by second proprietary step which reduces polydispersity and gives polyol with desired Equivalent  Weight.

Infigreen polyols have been developed with a range of range of hydroxyl numbers for products including flexible and rigid foam. The viscosity of InfiGreen polyols is comparable to the conventional polyols. Emery Oleochemicals has developed Infigreen 300, Infigreen 100, and Infigreen 60 polyols for flexible polyurethane foams.

This paper shows the performance of Emerox and Infigreen polyols in a model resilient TDI-based polyurethane foam system. Emerox and Infigreen polyols were added as partial replacements for polyether polyols in the model formulation, and systematically correlated with the changes in reactivity of the system and final properties of the free-rise and moulded foams.

Scrap polyurethane seat cushions are a big issue for the auto industry. Worldwide several billion lbs of scrap polyurethane foam is landfilled, either as production scrap or post-consumer scrap when cars are decommissioned. This has created 1 billion lbs (454kt) of landfilled auto seat foam alone.

Raw materials, grades and suppliers are shown in Table 1.

Table 1. Materials Used in Preparation of Model Flexible Resilient Polyurethane Foams
Designation	Type	Supplier
POLYOLS
Poly G 85-29	Ethylene oxide caped polyether triol (Eq. wt. = 2157)	Arch
DVV 6340	Catalytically Active Polyether Polyol (Eq. wt. = 1753.1)	Dow
Emerox® 14001	Polyester Polyol (Eq. Wt. = 935)	Emery
Emerox® 14055	Polyester Polyol (Eq. Wt. = 1100)	Emery
InfiGreen® 60	Aromatic polyether polyol (Eq. Wt. = 935) Experimental	Emery
InfiGreen® 100	Aromatic polyether polyol (Eq. Wt. = 311)	Emery
InfiGreen® 300	Aromatic polyether polyol (Eq. Wt. = 18)	Emery
SURFACTANTS
Tegostab B 4690	Polyether/Silicone Oil Mix	Evonik
CELL OPENER
Lumulse POE 26	Ethoxylated glycerol; Eq. Wt. = 416.2	Lambent
CROSS-LINKERS
DEOA 99%	Diethanolamine; Eq. Wt. = 35.04	Aldrich
CATALYSTS
Dabco 33LV	33% Triethylene diamine in dipropylene glycol	Air Products
Niax A1	bis(2-dimethylaminoethyl) ether	Momentive
BLOWING AGENT
	Water Deionized
ISOCYANATES
Lupranate TD80	2,4’- rich Toluene Diisocyanate (F=2.2; Eq. wt. = 87.54)	Dow

Preparation and testing of flexible foams In all cases 10% of model polyol was replaced by 10% of Emerox or Infigreen as straight substitution. No other changes were made to the formulation. All flexible foams were hand mixed with a laboratory high-torque mixer. For free-rise foams, polyol and isocyanate were mixed for 5 seconds, then transferred into a rectangular box, before cream time was reached. The foaming profile, including cream time, gel time, and rise time, was measured on all free-rise foams. After the rise time, the foams were immediately placed in an air-circulating oven preheated at 75°C for 30 minutes to complete the cure. Molded foams were made into blocks 30x30x5cm. The thoroughly mixed polyol and isocyanate were transferred to an aluminium mould preheated at 75°C before the cream time. After 210s in the mould at 75°C, foams were demoulded and crushed. After at least 24 hours of additional cure at room conditions, the foams were cut and tested. A list of test methods used in evaluation of the foams is shown in Table 2.  

Table 2. Methods Used for Testing Flexible Foams
FLEXIBLE FOAMS	Standard	Test
Core Density, kg/m3	ASTM D 3574	Test A
Resilience (Ball Rebound), %	ASTM D 3574	Test H
Tear Resistance, N/m	ASTM D 3574	Test F
Tear Strength, Die C	ASTM D624
Dry Compression Set	ASTM D 3574	Test D
(50% Deflection), % Loss	(Ct Calculation)
Wet Compression Set	ASTM D 3574	Test D, L
(50% Deflection), % Loss	(Ct Calculation)
CFD (25%,50%, and 65% Deflection), psi	ASTM D 3574	Test C
Tensile Strength, psi	ASTM D 3574	Test E
Elongation, %	ASTM D 3574	Test E

  Results and discussion I.  Emerox and Infigreen polyols – 10 percent polyol replacement Foam density Foams prepared with 10% of Emerox and 10% Infigreen exhibited similar or higher foam density compare to the reference foam for free-rise foams (see below). Resilience The foams prepared with 10% of Emerox or Infigreen polyols showed resilience higher than 50%, which is comparable to the reference foam. However, free-rise formulations containing Emerox 14055 and Infigreen 100 and moulded foam containing Infigreen 300 gave resilience just below 50% (see below). Hysteresis The free-rise foams prepared with 10% of Emerox or Infigreen were very close to the reference foam with hysteresis of 18-25%: reference foam hysteresis was 19%. The moulded foams’ hysteresis was 19-29% compared to 20% for the reference foam. Compression set data The wet and dry compression set data show the free-rise foams made with InfiGreen and Emerox polyols had comparable dry compression sets to the reference foam. Wet compression set was typically higher in free-rise foam with Infigreen and Emerox polyols compared to the reference foams. Molded foams containing Emerox and Infigreen polyols were comparable to the reference. The exception was the moulded foam formulation made with Infigreen 300. This had higher wet compression set than the reference. See below. Tensile properties The tensile strength of free-rise foams prepared with Emerox and Infigreen polyols was similar or slightly lower than the reference foam. The tensile strength of the tested foams was 11.2-14.8psi (77.2-101kPa) compared to the reference foam tensile strength of 14.4psi (99kPa) (see below). The moulded foams gave tensile strengths between 19.0—28.0psi (131-193kPa), although Infigreen 300 gave tensile strength of 13.9 psi (95.8kPa). Reference moulded foam had a tensile strength of 18.6psi (128.2kPa). Elongation at break of free-rise foams prepared with the Emery Oleochemicals’ polyols were overall comparable to the reference foam (see below). Tear strength The tear strength (Die C) of free-rise foams prepared with the drop-in polyols was higher than the reference foam. Typically it was 6.2-10.2 N/cm compared to 4.8 N/cm for the reference foam. (See below) With the exception of Infigreen 300 polyol formulation all the other substitutes in moulded foams gave higher tensile strength (Die C) than the reference. The tear strengths (Die C) for the polyol-substituted moulded foams were 19.0—28.0 N/cm and the reference foam was 18.6 N/m. Molded foam made with Infigreen 300 polyol had a tear strength of 13.9 N/cm The trouser tear strength of Emery Oleochemicals’ polyol free-rise foams was comparable or higher at 2.36-3.63 N/cm compared to the reference foam trouser strength of 2.27 N/cm. While moulded foams were generally higher or comparable to reference foams in terms of tear strength, Infigreen 300 polyol substitution resulted in a slightly lower trouser strength (see below). Constant Force Deflection (CFD) The CFD of free-rise foams was higher than reference foam except for the substitution with InfiGreen 300 which was comparable. In moulded foams Infigreen gave a lower CFD than the reference. The other substituted foams had higher CFD. We measured CFD by applying increasing pressure to samples until two levels of deflection were reached. The pressure needed to reach 25% deflection for polyol substituted foams was 0.4-1.19 psi (2.8-8.2 kPa) compared to the reference foam 25% CFD of 0.11 psi (0.76kPa). Free rise foams prepared with 5-20% of Emerox 14001 polyol had comparable density to the reference foam formulation and density increased with increased addition of Emerox 14001 up to the maximum addition of 50% by weight of the polyol component. Resiliency generally decreased in free-rise as the substitution rate of Emerox 14001 increased. The data shows Emerox 14001 can be substituted up to 15% polyol, without any modification in the formulation, and still produce free-rise foams with at least 50% resilience. The resiliency of moulded foams followed the same trend as the free-rise foams. It fell with increased loading of Emerox 14001. Molded foams containing up to 20% polyol substituted with Emerox 14001, had resiliency >50%. We expect it will be possible to modify the formulation to give highly resilient foams with more than 20% Emerox 14001. Below 5% of Emerox 14001 polyol substitution hysteresis was very close to the reference foam (18.9%). However, as the proportion of polyol was replaced by Emerox 14001, increased so did hysteresis. Compression set data Dry compression set was evaluated on samples subjected to 70°C for 22 hours. For the wet compression set evaluation, the samples were subjected to 50°C and 100% humidity for 22 hours. The data show that the free-rise foams with up to 30% substitution of Emerox 14001 had comparable dry compression set to the reference foam. There was no difference in wet compression set in free rise foams at up to 10% substitution of Emerox 14001. However at substitution levels at 15% and above the wet compression set was somewhat higher than the reference foam. Up to 30% of the polyol can be substituted with Emerox 14001 to give foam with comparable or slightly increase dry and wet compression set. We expect it will be possible to adjust formulations so resilient foams could be produced with Emerox 14001 with reduced dry and wet compression sets. Tensile properties At substitution levels between 5-50% tensile strength was comparable to reference foam. In moulded foams, tensile strength rose with the substitution rate. Overall, elongation at break of free-rise and moulded foams were comparable to the reference foams Compounded with the tensile strength data, it can be concluded that the addition of Emerox 14001 increases the toughness of the moulded resilient foams. Tear strength (die C) Overall, the tear strength (die C) of free-rise foams with up to 50% Emerox 14001 polyol was comparable to the reference foam. Molded foams showed increase tear strength (die C) with the addition of Emerox 14001 (see below). Constant Force Deflection (CFD) In free-rise CFD increased with the degree of Emerox 14001 substitution. In moulded foams CFD remained fairly unchanged with the addition of Emerox 14001. Initial data clearly shows that Emerox 14001 and 14055 and Infigreen 60, 100 and 300 polyols, at 10%% substitution, were suitable for high resilience foam applications.

Table 3. Reaction Profile for Emerox® 14001 Polyol Substituted HR Free-Rise
Weight Substitution	0	5	10	20	30	40
Mix Time (s)	5	5	5	5	5	5
Cream Time,	9	9	9	10	15	14
Gel Time (s)	24	24	25	25	28	30
Rise Time, (s)	45	55	85	75	70	74
Post-cure Time	30 min @
Time + Temp	75°C

Overall, the foams prepared from these polyols exhibited comparable properties as the model reference foams for both free rise and moulded foam applications. In cases where the from the addition of Infigreen or Emerox polyols were negative, it is believed that adjustments to the foam formulations could be made to overcome these deficiencies as no other adjustments to the foam formulation were made in this study. The data for Emerox 14001 demonstrates that this polyol can be used in TDI resilient foam formulation at reasonable high loading. The addition of Emerox 14001 did not significantly affect the foaming reaction profile, and stable free rise foams were produced with up to 50% drop in substitution rate. It was determined that the addition of Emerox 14001 improved the overall tensile properties and tear strength of moulded TDI foams. In moulded TDI foams, addition of Emerox 14001 at up to 30% substitution rate did not affect the dry and wet compression sets. As is the case with most NOPs, the drop in addition of Emerox 14001 did result in reduction in resilience and increase in hysteresis, but it is expected that these properties can be improved with formulation adjustments. Authors Michael Brooks, Ashley Maloney, Steve Turner, Jeff Barnhorst, Bryan King and Ibrahim Sendijarevic Emery Oleochemicals, 4900 Este avenue, Cincinnati, Ohio Acknowledgements We would like to thank Vahid Sendijarevic and his team at Troy Polymers for their guidance and assistance with foaming experiments and data collection. About Emery Oleochemicals With revenue of US $1billion (2013), the company is headquartered in Malaysia with manufacturing plants spanning three continents - Asia pacific, North America, and Europe. Emery Oleochemicals’ global operations are backed by a diverse workforce and an extensive distribution network covering over 50 countries worldwide.