polyurethane chemistry and · past, present and future dr. xudongfeng executive director institute...
TRANSCRIPT
4/4/2013
1
Polyurethane Chemistry and Products:Past, Present and Future
Dr. Xudong FengExecutive DirectorExecutive Director
Institute For Molecular EngineeringUniversity of Chicago
Agenda
• Polyurethane Chemistry Introduction
• Applications – Chemistry and Socioeconomic Impact
• Innovation in PU Chemistry
• Polyurethane (Isocyanate) Emissions and DegradationDegradation
• Health and Safety Considerations
• Summary
4/4/2013
2
Introduction
UrethaneIsocyanate Alcohol
AmineIsocyanate Water CO2 gas
Otto BayerDR Patent 11.11.1937
UreaIsocyanate Amine
Commercial Isocyanates in the Polyurethane Industry
• Aromatic– TDI MDI MonomersTDI, MDI Monomers– pMDI (polymeric MDI)
• AliphaticHDI IPDI H MDI– HDI, IPDI, H12MDI Monomers
– HDI and IPDI homopolymers
4/4/2013
3
Isocyanate Reaction Pathways
Uretdione“Dimer”
RNHCOOR’
RNHCO
Allophanate
RNCO
NO O
R‐NCO
(RNHCOOH)
H2O
OCN‐R‐N=C=N‐RNCO
Carbodiimide
Uretonimine
RNHCOOR’Urethane
R’OH
R‐NCO
IsocyanurateTrimer
Allophanate
RNCO
NO O
(RNHCOOH)
RNH2 + CO2
RNHCONHRUrea
RNHCONHR’Urea
RNHCONHR’
RNHCOBiuret
R‐NCORHHCOR’ + CO2
Amide
Monomeric Diisocyanate Relative Reactivity
Isocyanate k1 k2
TDI 400 33TDI 400 33
MDI 320 110
HDI 1 0.50
H12MDI 0.57 0.40
IPDI 0.62 0.23
OCN R NCOHO R'
OCN R NCO
OH
R'HO R"
R" OC
N
O
RH
NH
CO
O
R'k1 k2
4/4/2013
4
Relative volatility of isocyanate types
• HDI Isocyanurate trimer 0.00052• HDI Biuret 0.93• Monomeric MDI 1• Polymeric MDI 1• H12MDI diisocyanate 1• IPDI diisocyanate 48• HDI diisocyanate 1,100• TDI diisocyanate 2,500y ,• Water 1,800,000• Solvent (methyl ethyl ketone) 9,100,000• Methyl isocyanate 34,800,000
Polymeric MDI Composition
50% PURE
TARS ETC.
2,4’
4,4’
HIGH FUNCTIONALITY SPECIES
Diisocyanate
Triisocyanate
2 3 4 5 6 7 8 9 Others
POLYMERIC MDI IS A MIXTURE OF ISOMERS AND OLIGOMERS WITH ANAVERAGE FUNCTIONALITY OF 2.7 AND 31.5% NCO GROUPS
FUNCTIONALITY
4/4/2013
5
Polymeric Aliphatic Isocyanates
NH
(CH2)6 NCO
N (CH ) NCON(CH2)6OCN
O
NH
(CH2)6 NCOO
(CH2)6OCN
(CH2)6
NCO
(CH2)6 NCON
N
N
O
OO N
O
N
O
N O
(CH2)6-NCO
(CH2)6OCN
(CH2)6OCN
Asymmetric Trimer
(CH 2)6 NCOOCN
HDI
Biuret
Trimer Isocyanurate Iminooxadiazindione
NH
(CH2)6 NCON(CH2)6OCN
OO
O
R
Allophanate
N N
O
O
(CH2)6(CH2)6 NCOOCN
Dimer Uretdione
Aliphatic Polyisocyanate Oligomers
Trimer (n=3) Typical Oligomer Breakdown
Pentamer (n=5)
Heptamer (n=7)
n = 1 <0.01%n = 3 ~ 50%n = 5 ~ 20%n = 7 ~ 10%n = 9 ~ 6%n = >9 ~ 14%n = oligomer #
*Product contains fractions of trimers, pentamers, heptamers, and higher oligomers.
N N
NOR
O
(C H2)6O
RN N
N OR
O
OR
Pentamer
4/4/2013
6
Chemistry introductionUnparalleled Versatility and Utility
NN
O
O
O
O
Segmentation: Chemistry is the key !• Hard and soft segments
P l l t i t lliHN
HN OO
HN
HN
O
O
O
OHydrogen bonding inUrethane Linkages:
• acts as non‐covalent “crosslinking”•Vital to good elastomeric properties
• Polyols to give crystalline oramorphous properties
Soft segment Hard segment
Agenda
• Polyurethane Chemistry Introduction
• Applications – Chemistry and Socioeconomic Impact
• Innovation in PU Chemistry
• Polyurethane (Isocyanate) Emissions and DegradationDegradation
• Health and Safety Considerations
• Summary
4/4/2013
7
Polyurethane Application Versatility74.968.662.456.2
1.2
1.11.00 9
SealantsC.A.S.EC.A.S.E
49.943.737.431.225.018.712.56.25.65.04.43.73 1
Density, lbs/ft 3
0.90.80.70.60.50.40.30.20.10.090.080 07
Specific Gravity, gm
s/cc
FoamFoam
3.12.51.91.30.6
0.070.060.050.040.030.020.01
0 10 20 30 40 50 60 70 80 90 40 50 60 70 80
Shore A Hardness Shore D Hardness
Polyurethane Foam Cell Formation
BUBBLES GROW BUT DONOT TOUCH AT THIS STAGE THE PU IS MICROCELLULAR
BUBBLES TOUCH TO FORM
CO2
CARBON DIOXIDE SEPARATESFROM REACTING PHASE AND DIFFUSES INTO NUCLEATION
POINTS
THE PU IS MICROCELLULAR TO FORMCELL WINDOWS
CLOSED
CLOSED CELL FOAM
CO2 CO2
MIXED LIQUIDSWITH
NUCLEATING AIR
INTERCONNECTING LABYRINTH
CLOSED CELL
OPEN CELL FOAM
4/4/2013
8
Rigid PU Foam Chemistry
• Polyols– Low MW– High Functionality
• pMDI – highly branched• Structure
– Highly crosslinked– Rigid– Small closed cell traps gases– Thermal insulation
Flexible PU Foam Chemistry• Polyether Polyols
– Vary MW and functionality• TDI diisocyanateTDI diisocyanate
– Lower crosslink density than rigid• Water reaction produces Carbon Dioxide as
the principle method of expanding the foam • Additives controls
– Reactivity– Cell size and breathability– Flammability– Color
• High Resiliency Foam – Memory Foam– Hybrid of Rigid and Flexible
4/4/2013
9
Coatings TechnologyWide Variety of application techniques and markets
Solventborne Waterborne100% solids
1 Component‐Moisture cure‐Blocked Iso
2 Component‐Polyol‐Crosslinker
2 Component‐Polyol/urea‐Crosslinker
2 Component‐PolyurethaneDispersion
‐Crosslinker
1 Component‐PolyurethaneDispersion
Crosslinking improves propertiesCrosslinking improves propertiesAbrasionChemicalWeatheringStrength
Thermoplastic Polyurethane (TPU)
Aliphatic I t
Aromatic I t
Non-yellowingUV resistance
Polyether
IsocyanateIsocyanate
Polyester
UV resistance
• Cut & Scratch Resistance• Superior Wear Resistance
• Hydrolysis Resistance• Fungus & Moisture Resistance
• Higher Mechanical Properties• Fuel & Oil Resistance • Heat Stability• Better Inherent UV Stability
• Cold Temperature Flexibility • Resistant to Salt Water Cracking • Ozone Resistance• Better Transparency
4/4/2013
10
Socioeconomic Impact of Polyurethanes in the US*
• The PU Industry directly generates $19.7 B in output and 37,700 jobsoutput and 37,700 jobs
• Multiplier effect impacts jobs and output in downstream industries:• Additionally, the PU industry indirectlysupports $40.1 B in output and 165,000 jobs
• In total: $59.9 B in output and 202,600 jobs$ p , j• PU products are used in industries generating $245.5 B in output and employing nearly 1 million workers
*”The Economic Impact of the Polyurethane Industry in 2010”, Economics & Statistics Department of the American Chemistry Council
Agenda
• Polyurethane Chemistry Introduction
• Applications – Chemistry and Socioeconomic Impact
• Innovation in PU Chemistry
• Polyurethane (Isocyanate) Emissions and DegradationDegradation
• Health and Safety Considerations
• Summary
4/4/2013
11
Historical Development: Isocyanates and Polyurethane Technologies
1930’s Isocyanates/urethanes developed by Otto Bayer 1940’s Addition to alkyds to improve quality/productivity1950’s Commercialization of Flexible Foam (TDI/Polyester)1960’s Development of aliphatic polyurethane coatings
PMDI for rigid foams1970’s Aqueous polyurethane dispersions (PUDs)
Elastomers, Footwear, High Resilience Flex FoamUrethane acrylate resins
1980’s Two component (2K) urethane coatingsSpray foam building insulationAutomotive energy absorption for passenger safetyAutomotive energy absorption for passenger safety
1990’s 2K waterborne coatingsHydrophilic polyisocyanates and functional PUDsCommercialization of visco-elastic memory foamRadiation curable PUDs
2000’s 2K WB PUR with excellent chemical resistanceCo-solvent free PUD/acrylic dispersions
Rigid PUR / PIR Insulation Foams Innovation Drivers
“PolyIso”Growth
HCFCsHFCs HCs
HFOs
“Microcell”
PolyIso
“Polyurethane”Low “ODP”
No “ODP”
Page 22
1960 20121980 2000Oil EmbargoEPCAOzone DepletionFlammability Stds.
Montreal ProtocolNAECA / CAAEnergy StandardsCodes
HCFCs
Energy StandardsCodes“Green” Stds. / CodesGHG concerns
CFCs
4/4/2013
12
Innovation Driver in Coatings Applications
N
ON
N
NO
O O
OCN
H
N SO3 NR3H
owth O
OOUrethaneacrylate
Ionic hydrophilic trimer
N N
N OO
OR
R
R
NCO
NCOOCNN N
O
O
RR NCOOCN
ROCN N CO
CO
O
NH
R
R'
NCO
OCN
O O O
Gro
UretdionTrimer
Allophanate
R O C NH
R'n
1960 2010
NH
O
O R' O
O
NH
R NH
O
nO
OCN – R – N – CO – N – R – NCO
CO – N – R – NCOH
H
Biuret
Polyurethanes ‐ Dispersions/Prepolymers
Enable Waterborne system
Agenda
• Polyurethane Chemistry Introduction
• Applications – Chemistry and Socioeconomic Impact
• Innovation in PU Chemistry
• Polyurethane (Isocyanate) Emissions and DegradationDegradation
• Health and Safety Considerations
• Summary
4/4/2013
13
Polyurethane Application/Use Considerations‐ Aerosolizing
• Processes involve spray applications (e.g., foam and coatings) can generate airbornefoam and coatings) can generate airborne monomeric and polymeric isocyanate aerosols
• Monomeric isocyanate vapor pressures influence potential airborne concentrations: ‐ the more volatile isocyanate monomers (e.g., TDI
and HDI) have a greater potential to release airborne concentrations than the less volatile isocyanate monomers (e.g., MDI and H12MDI)
• Releases of airborne isocyanate can occur when a polyurethane product is thermally degraded
Polyurethane Application/Use Considerations– Thermal Degradation
• Polyurethane, like all organic material, will burn when supplied with sufficient heat and air
• When a fire occurs the gases produced depend upon the temperature, the amount of oxygen and some catalytic effects.
• In a fire situation typical off‐gases of PUR include:– Carbon dioxide, carbon monoxide and carbon (soot)– Water– Nitrogen oxides (NO2, N2O, N2O5) commonly referred to as NOx– Hydrogen cyanide– Isocyanates
• Other plastics and wood emit similar gases when burned
4/4/2013
14
Polyurethane Products in Fires: Acute Toxicity of Smoke and Fire Gases*
• Toxic effluents in fires are influenced by multiple factors.
• Combustible materials (synthetic or man made) generally• Combustible materials (synthetic or man‐made) generally produce toxic products when burned.
• Carbon monoxide is the most prevalent and abundant toxicant in fires involving natural products and synthetic materials under most combustion conditions.
• The acute toxicity of natural and synthetic materials e acute to c ty o atu a a d sy t et c ate a s(including polyurethanes) appears to be more similar than different.
* Polyurethane Products in Fires: Acute Toxicity of Smoke and Fire Gases. T. Landry, J. Pauluhn, D. Daems, K. Reimann. International Isocyanate Institute.
Thermal Degradation of Car Paintin Body Shop Repair*
• Generation of airborne isocyanates was identified during cutting, grinding, and sanding operations in Body Repair Shops
• Highest levels of airborne
Grind
ing
isocyanates were seen during the cutting process Cutting
*Boutin, M., Dufresne, A., Ostiguy, C., Lesage J. Determination of Airborne Isocyanates Generated During the Thermal Degradation of Car Paint in Body Repair Shops . Annals of Occupational Hygiene, vol. 50, no 4, 2006, p. 385‐393.
4/4/2013
15
Agenda
• Polyurethane Chemistry Introduction
• Applications – Chemistry and Socioeconomic Impact
• Innovation in PU Chemistry
• Polyurethane Emission and Degradation ToxicityToxicity
• Health and Safety Considerations
• Summary
Relative volatility of isocyanate types
• HDI Isocyanurate trimer 0.00052• HDI Biuret 0.93• Monomeric MDI 1• Polymeric MDI 1• H12MDI diisocyanate 1• IPDI diisocyanate 48• HDI diisocyanate 1,100• TDI diisocyanate 2,500y ,• Water 1,800,000• Solvent (methyl ethyl ketone) 9,100,000• Methyl isocyanate 34,800,000
4/4/2013
16
Health and Safety Considerations• Exposure Routes
– Inhalation, Dermal, Eye, Ingestion
• Hazard communication– MSDS and Label Review– Safe Use & Handling Literature Review– Workplace Training
• Best Practices: – Routine Air Monitoring – Appropriately designed ventilation; particularly local exhaust pp p y g ; p y
ventilation – Proper use of personal protective equipment (PPE)– Effective workplace practices or housekeeping standards– Medical Surveilance
Agenda
• Polyurethane Chemistry Introduction
• Applications – Chemistry and Socioeconomic Impact
• Innovation in PU Chemistry
• Polyurethane (Isocyanate) Emissions and DegradationDegradation
• Health and Safety Considerations
• Summary
4/4/2013
17
Summary
• PUR chemistry offers versatility and unique properties to meet various application requirements
• PUR chemistry contributes to sustainability by directly impacting reduced energy usage and solvent levels, while extending product life
• Similar to other chemicals, isocyanates used in the polyurethanes industry are reactive chemicals that need to be handled in a safe manner. Such that:– There is a need for appropriately designed ventilation, proper
use of personal protective equipment (PPE), and effective workplace practices/housekeeping standards
– Safe use and handling of isocyanates should be achieved in accordance with the principals of Product Stewardship and Best Industry Practices.
Backup
4/4/2013
18
Polyurethane Products in Fires: Acute Toxicity of Smoke and Fire Gases
Thermoplastic Polyurethane (TPU)
Raw Materials: HO\/\/\/\/\/OH + OCN - R - NCO + HO\/\/\OH
Polyol Diisocyanate Chain Extender
TPU is a multi-phase block-copolymer made from three raw materials:
Polyol Diisocyanate Chain Extender
MultiphaseD i St t
/\/\/\/\/\/ \/\/\/\/\/ \/\/\/\/\/\/\/\/\/\/\ \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/ \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/ /\/\/\/\/\/\/\/\/\/\/\/\/\ \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/ \/\/\/\/\/\/\/\
Polymer Block:
O O O OII II II II
- CHN - R - NHC - O\/\/\/\/\/O - CNH - R - NHC - O\/\/\O -n
Soft segment Hard segment
Domain Structure: /\/\ /\/\/\/\/\/\/\/\/ /\/\/\/\/\/\/\/\/\/\/ \/\/\/\/\/\/\/\
HS-Crystallite
Hard Segment: Imparts rigidity, hardness, & flexural modulus characteristics and determines the upper use of temperature.
Soft Segment: Imparts elasticity, flexibility & resilience and determines the low temperature performance.
4/4/2013
19
2K Solventborne CoreactantsCoreactants typically make up a majority of the polyurethane resin systemStrongly influencing modulus, Tg, elasticity, VOC
• Acrylics– Fast physical dry– Low iso demand– UV resistance
• Polyesters– Chemical Resistance– Versatile chemistry
UV i t
• Polyethers– Low cost– Hydrolytic stability– High Solids
• Polyaspartates– Weatherable– High Solids
Hi h P d ti it– UV resistance – High Productivity
• Polyamines– Rapid cure– High Solids– Chain extender
2K Solventborne Crosslinkers
HDI PolyisocyanateBiuretBiuret
Low MWBiuret
Low MWBiuret
High MWTrimer
High MWTrimer
Fast Drying
IPDI Polyisocyanate
HDI/IPDI Polyisocyanateblend
L o w V i s c o s i t y
HDI Polyisocyanate
IsocyanurateTrimer
IsocyanurateTrimer
UretdioneUretdione Low MWTrimer
Low MWTrimerAllophanateAllophanate
ModifiedTrimersModifiedTrimers PrepolymersPrepolymers
IPDIIPDIHardness
Blends
Blends
AsymmetricTrimer
AsymmetricTrimer
IPDITrimer
IPDITrimerSuitable for blending in
2K WB coatings UV and weather resistanceWater, chemical, solvent resistanceCombination of hardness and flexibilityVariations in Structure and MW modify physical properties
4/4/2013
20
2K Waterborne Crosslinkers
Low Viscosity Low VOC
Higher Functionality
Low Viscosity, Low VOC
AllophanateAllophanate
ImprovedPerformance
RobustProcessing
ImprovedChemical
Resistance
ImprovedWeather
Resistance
Easy mixing
IsocyanurateTrimer
IsocyanurateTrimer
ureaureaAllophanateAllophanate UreaUrea
Chemicalresistance Easy mixing
Polyether modified
Lower MW Lower MW
Fast Drying (Tg)Chemical resistance
IsocyanurateTrimer
IsocyanurateTrimer
IPDI Polyisocyanate
HDI Polyisocyanate
Lower Viscosity Lower Viscosity