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Funded by: Funded by:
UNIVERSITY OF CASTILLA-LA MANCHA
INSTITUTE OF CHEMICAL AND ENVIRONMENTAL
TECHNOLOGY
GLOBAL PROCESS OF FLEXIBLE POLYURETHANE FOAMS RECYCLING BY
SPLIT – PHASE GLYCOLYSIS
D. Simón, A. de Lucas, Ana M. Borreguero and Juan
F. Rodríguez
Funded by: Funded by:
1.1. Essential concepts
1.2. Recycling Processes
i) Physical Processes
ii) Chemical Processes
INDEX
1. INTRODUCTION
2. EXPERIMENTAL INSTALLATION
3. RESULTS AND DISCUSSION
3.2. Catalyst selection
3.3. Optimal conditions
3.4. Glycolysis upper phase
3.5. Glycolysis bottom phase
3.1. Low weight glycol selection
Funded by: Funded by:
1. INTRODUCTION
1.1. ESSENTIAL CONCEPTS
Polyurethane synthesis
n HO-R-OH + n O=C=N-R´-N=C=O [ -CO-NH-R´-NH-CO-O-R-O- ]n
Polyol Isocyanate Urethane
Polyurethane types
-Foams
-CASE
Flexible Rigid
Funded by: Funded by:
1. INTRODUCTION
1.1. ESSENTIAL CONCEPTS
PU world consumption in 2010
>12 million tons
6º in the plastic market
Production in Spain in 2010
≈ 200.000 tons
7º in the national plastic market
elastomers
8.8% duromers 0.4%
flexible foams
44.2% integral foams
7.0%
rigid foams
37.3%
others
2.3%
GREAT AMOUNT OF WASTES
RECYCLING
Funded by: Funded by:
1. INTRODUCTION
1.2. RECYCLING PROCESSES
i) Physical Processes
ii) Chemical Processes
• Hydrolysis
Φ-NH-CO-O-R’ + H2O Φ-NH2 + CO2 + HO-R’
Urethane Water Amine Polyol
• Aminolysis
Φ-NH-CO-O-R’ + NH2-R” Φ-NH-CO-NH-R” + HO-R’
Urethane Amine Urea Polyol
• Phosphorolysis
• Pyrolysis
Funded by: Funded by:
1. INTRODUCTION
1.2. RECYCLING PROCESSES
ii) Chemical Processes
• Glycolysis
Φ-NH-CO-O-R’ + OH-R”-OH Φ-NH-CO-O-R”-OH + HO-R’
Urethane Glycol Carbamate Polyol
Large glycol excess Biphasic product Split – Phase
Bottom phase
Upper phase
Recovered polyol Glycol excess
Funded by: Funded by:
2. EXPERIMENTAL INSTALLATION
Scrap PU foam Recovered Polyol
Funded by: Funded by:
GLYCOLYSIS AGENT (G.A):
Low weight glycol + catalyst
INDUSTRIAL PU FOAM WASTE
Polyether Polyol F-4811 + TDI
RECOVERED POLYOL
GLYCOLYSIS AGENT EXCESS
1. JACKETED 1L FLASK
2. REFLUXING CONDENSER
3. N2 ATMOSPHERE
4. STIRRER
5. TEMPERATURE CONTROL SYSTEM
6. CONTINUOUS FEEDER
2. EXPERIMENTAL INSTALLATION
Funded by: Funded by:
3. RESULTS AND DISCUSSION
3.1. LOW WEIGHT GLYCOL SELECTION
glycol / DEA
0 20 40 60 80 100 120 140 160 180 200 0
5
10
15
20
25
MEG
MPG DEG
0 20 40 60 80 100 120 140 160 180 200
0
10
20
30
40
50
60
70
80
90
MEG
MPG
DEG
OLIGOMERS POLYOL
WPU:Wag = 1:1.5
WDEG:WDEA = 6:1
T = 190 ºC
Funded by: Funded by:
3. RESULTS AND DISCUSSION
3.1. LOW WEIGHT GLYCOL SELECTION
glycol / DEA
Propylenic glycols increase phases mutual
solubility
MPG provides a strong polluted
product
DPG does not allow phase separation
DEG SEEMS TO OFFER THE BEST
PERFORMANCE
DPG
polyol
10 12 14 16 18
10 min
40 min
1 h 40 min
3 h 40 min
retention time (min) GLYCOL MEG DEG MPG DPG*
Viscosity 25ºC (cp) 830 584 632 346
Acidity (mg KOH/g) 0.016 0.010 0.014 0.073
Hydroxyl number (mg KOH/g) 157 155 179 -
Water (%) 0.55 0.42 0.23 0.51
% Polyol ( w/w) 72 83 63 <25
Optimal glycol: DEG
Funded by: Funded by:
3. RESULTS AND DISCUSSION
3.2. CATALYST SELECTION
ALKALINE – ALKALINE EARTH
0
10
20
30
40
50
60
70
80
90
0 50 100 150 200
time reaction (min)
% b
y w
eig
ht
Li
Na
K
Ca
Sr
Sn
Ba
0
5
10
15
20
0 50 100 150 200
time reaction (min)
% b
y w
eig
ht Li
Na
K
Ca
Sr
Ba
Sn
WPU:WDEG = 1:1.5
Ccat =6*10-2 m DEG
Tª = 190 ºC
Funded by: Funded by:
TRANSITION METAL
3. RESULTS AND DISCUSSION
3.2. CATALYST SELECTION
0
10
20
30
40
50
60
70
80
90
0 50 100 150 200
time reaction (min)
% b
y w
eig
ht
Co
Ni
Cu
Zn
Y
Sn
0
2
4
6
8
10
12
14
16
18
20
0 50 100 150 200
time reaction (min)
% b
y w
eig
ht
Co
Ni
Cu
Zn
Y
Sn
WPU:WDEG = 1:1.5
Ccat =6*10-2 m DEG
Tª = 190 ºC
Funded by: Funded by:
CATION Viscosity
25ºC (cp)
Hydroxyl number
(mg KOH/g)
Total amine
(mg KOH/g) Poliol (%)
Li 570 172 6.69 82.4
Na 584 178 6.04 74.7
K 591 171 9.59 79.0
Ca 576 171 8.78 79.3
Sr 598 176 7.64 81.5
Ba 619 197 0.40 79.3
Co 1068 191 8.80 75.3
Ni 667 181 14.60 79.0
Cu 1454 235 0.28 71.0
Zn 705 184 16.27 80.3
Y > 2000 175 19.62 51.2
Sn 550 198 5.23 82.3
3. RESULTS AND DISCUSSION
STANNOUS OCTOATE IMPROVED
ALTERNATIVE TO THE DESCRIBED CATALYSTS
3.2. CATALYST SELECTION
Funded by: Funded by:
Surprisingly Sn Octoate that
catalyses the PU foaming process,
also catalyses the glycolysis
process¡¡¡
3. RESULTS AND DISCUSSION
3.2. CATALYST SELECTION
Funded by: Funded by:
3. RESULTS AND DISCUSSION
3.3. OPTIMAL CONDITIONS
3.3.1. CATALYST CONCENTRATION
Reaction # PU foam (g) DEG (g) Stannous octoate (g) Stannous octoate
(moles)
Stannous octoate
(% G.A.)
R-1 300 440 10.5 0.026 2.3
R-2 300 442 8 0.020 1.8
R-3 300 444 6 0.015 1.3
R-4 300 446 4 0.010 0.9
Tr=190ºC WPU:WG.A=1:1.5
Funded by: Funded by:
3. RESULTS AND DISCUSSION
3.3. OPTIMAL CONDITIONS
3.3.1. CATALYST CONCENTRATION
At low catalyst concentration, there is a strong dependence with the improvement in the reaction time, but at high concentrations
the slope of the dependence curve decreases.
From 1.3 % to up the improvement in the reaction rate would not be noticeable, approaching zero order behaviour.
Concentration of polyol in the upper phase is not a function of catalyst concentration.
Stannous octoate optimal concentration: 1.3 % G.A.
Funded by: Funded by:
3. RESULTS AND DISCUSSION
3.3. OPTIMAL CONDITIONS
3.3.2. WPU:WG.A
Reaction # PU foam (g) DEG (g) Stannous octoate(g)
Stannous octoate
(moles) WPU:WG.A
R-3 300 444 6 0.015 1:1.5
R-5 400 444 6 0.015 1:1.125
R-6 500 444 6 0.015 1:0.9
WPU:WG.A.=1:0.9; Wcat=1.3 % G.A.; Treaction=189ºC. a) Final product view
b) Homogeneous product. Intense orange coloration detail
a) b)
Tr=190ºC WSnOct=1.3% G.A
Funded by: Funded by:
3. RESULTS AND DISCUSSION
3.3. OPTIMAL CONDITIONS
3.3.2. WPU:WG.A
WPU:WG.A.= 1:0.9 (500 g PU) → low polyol content in the upper phase
WPU:WG.A. = 1:1.125 (400 g PU) → similar polyol content in the upper phase in comparison with 1 : 1.5 ratio (300 g PU)
WPU:WG.A. = 1:1.125 (400 g PU) → reaction time is only 10 minutes more in comparison with 1: 1.5 ratio (300 g PU)
Optimal mass ratio of PU foam to glycolysis agent: 1 : 1.125
Tr=190ºC
WSnOct=1.3% G.A
Funded by: Funded by:
3. RESULTS AND DISCUSSION
3.3. OPTIMAL CONDITIONS
3.3.3. Temperature
Reaction # Temperature (ºC) WPU:WG.A PU foam(g) DEG (g) Stannous octoate
(g)
Stannous octoate
(moles)
R-5 189 1:1.125 400 444 6 0.015
R-7 184 1:1.125 400 444 6 0.015
R-8 179 1:1.125 400 444 6 0.015
179 º C → low polyol content in the upper phase
homogenous product
184 º C → slow recovery process(150 min reaction time)
>189 º C → DEG excessive evaporation
increase of the extent of secondary reactions
Optimal reaction temperature: 189 ºC
→
→
WPU:WG.A=1:1.125 WSnOct=1.3% G.A
Funded by: Funded by:
3. RESULTS AND DISCUSSION
SCRAP FROM
FLEXIBLE PU FOAM
FRESH GLYCOL
CATALYST
TWO PHASE
GLYCOLYSIS
RIGID
POLYOL
BOTTOM PHASE
ALCOXYLATION
VACUUM
DISTILLATION
RECOVERED
GLYCOL
RESIDUE
PROPYLENE
OXIDE
CATALYST RIGID PU
FOAM
UPPER
PHASE
FLEXIBLE
PU FOAM
EXTRACTION
WATER
FLEXIBLE
POLYOL
EXTRACT
Funded by: Funded by:
3. RESULTS AND DISCUSSION
3.4. GLYCOLYSIS UPPER PHASE
Liquid - Liquid Extraction
Optimal Conditions
Temperature: 90ºC
pH: 4-5
Mass ratio: 1:1
Centrifugation
Glycolysis Upper Phase Glycolysis Upper Phase after L-L Extraction
Hydroxyl number(mg KOH/g) 198 Hydroxyl number(mg KOH/g) 63
Funded by: Funded by:
3. RESULTS AND DISCUSSION
3.4. GLYCOLYSIS UPPER PHASE
FOAM FORMULATIONS
A100-R0 A75-R25 A50-R50 A0-R100
ALCUPOL F-4811 100 75 50 -
Recovered polyol - 25 50 100
OHN polyol mixture 48 50.5 58 63
Water 4.60 4.60 4.60 4.60
Tegoamin 33 0.10 0.10 0.10 0.10
Niax A-1 0.05 0.05 0.05 0.05
Silicon L-620 LV 1.40 1.40 1.40 1.40
Stannous octoate 0.20 0.20 0.20 020
TDI (80:20) 54.58 54.99 56.21 57.02
Index 105 105 105 105
REPLACEMENT UP TO 50% WITHOUT CHANGE
Funded by: Funded by:
3. RESULTS AND DISCUSSION
SCRAP FROM
FLEXIBLE PU FOAM
FRESH GLYCOL
CATALYST
TWO PHASE
GLYCOLYSIS
RIGID
POLYOL
BOTTOM PHASE
ALCOXYLATION
VACUUM
DISTILLATION
RECOVERED
GLYCOL
RESIDUE
PROPYLENE
OXIDE
CATALYST RIGID PU
FOAM
UPPER
PHASE
FLEXIBLE
PU FOAM
EXTRACTION
WATER
FLEXIBLE
POLYOL
EXTRACT
Funded by: Funded by:
10 12 14 16 18
distillate
bottoms
inte
nsit
y (
a.u
.)
retention time (min)
50 mbar DEG
Vacuum distillation
50 mbar
0 50 100 150 200 2500
5
10
15
20
FRESH DEG
RECOVERED
% b
y w
eig
ht
reaction time (min)
WPU:WGA = 1:1.5
WDEG:WOctSn = 3.4*10-2 m
T = 189 ºC:1
Reuse of most excess of glycol after
catalyst adjustment:
OLIGOMERS
3. RESULTS AND DISCUSSION
3.5. GLYCOLYSIS BOTTOM PHASE
Funded by: Funded by:
Mw eq= 147 g/mol
POLYOL INITIATOR mol INITIATOR mol KOH/mol
INITIATOR
mol PO/mol
INITIATOR
SYNTHESIS
TIME (min)
TDA-1 TDA 1.64 0.0208 6.345 80
RDES-0.5 RDES 0.41 0.0205 3.146 74
RDES-1 RDES 0.41 0.0205 6.268 123
RDES-2 RDES 0.41 0.0205 12.537 280
retention time (min)
10 15
residuo de vacio
inte
nsid
ad
(u
.a.)
tiempo de retención (min)
Pm ≈ 300
Pm ≈ 175
DEG
inte
nsity (
a.u
.)
vacuum residue Contains active H :
DEG, aromatic amines, carbamates…
NH2H2N
Polyol R499 based on TDA
3. RESULTS AND DISCUSSION
3.5. GLYCOLYSIS BOTTOM PHASE
Funded by: Funded by:
T100-125 T50-125 T0-125
R-458 100 100 100
TDA-1 101 50 0
RDES-1 0 50 100
Water 1.02 1.09 1.02
POLYCAT-8 1.04 1.04 1.07
Tegostab B8404 2.18 2.13 2.09
MDI 264 249 237
Index 125 124 125
Tc(s) 15 20 20
Tmc(s) 110 110 97
Density (Kg m-3) 72 63 67
T50-125
T0-125
T100-125
BOTTOM PHASE VALORIZATION BOTTOM PHASE VALORIZATION: foaming
FOAM FORMULATIONS
VACCUM RESIDUE CAN BE USED AS
INITIATOR IN THE SYNTHESIS OF NEW
POLYOLS
Funded by: Funded by:
Diego Simón Herrero
UNIVERSITY OF CASTILLA-LA MANCHA
INSTITUTE OF CHEMICAL AND ENVIRONMENTAL
TECHNOLOGY
GLOBAL PROCESS OF FLEXIBLE POLYURETHANE FOAMS RECYCLING BY
SPLIT – PHASE GLYCOLYSIS