polyurea spray elastomers an overview of current technology
TRANSCRIPT
Jerry L. Reddinger and Kenneth M. HillmanHuntsman Corporation
Austin, Texas USA
■ 1980’s: Texaco’s Austin Research Laboratories develop polyurea reaction-injection-molding (RIM) for automotive exterior body panel applications.
■ 1989: Texaco’s Austin Research Laboratories develop and introduce 100% solids polyurea spray elastomer coatings.
■ 1990’s: Numerous equipment advances by industry leaders.
■ 1990’s: Huntsman Corporation and ICI Polyurethanes co-develop and commercialize isocyanate prepolymers for polyurea spray.
■ 1990’s: Introduction of key secondary amine chain extenders for use in polyurea elastomer coatings.
■ 2000: Formation of Polyurea Development Association
UreaLinkage
UrethaneLinkage
NR
H
O
O
R'O N
O
Hn
R'HO OH
ROCN NCO +
Catalyst
IsocyanatePrepolymer
Polyol
POLYURETHANEPOLYURETHANE
NR
H
N
O
R'N N
O
HH HnR'
H2N NH2R
OCN NCO +
IsocyanatePrepolymer
Polyamine
POLYUREAPOLYUREA
ResinComponent
POLYUREA Class 1Hybrid
Class 2Hybrid
Class 3Hybrid
PU
MMaaiinn Polyetheramine Polyetheramine Polyetheramine Polyol Polyol
CChhaaiinnEExxtteennddeerr Polyamine
Polyamine(Hydroxyl
Containing)Polyol Polyamine Polyol
CCaattaallyyssttPPaacckkaaggee NONE NONE YES YES YES
NOTE: A myriad of other additives can be incorporated into any of these systems. Examples include pigments, adhesion promoters, UV-absorbers, anti-oxidants, and texturing agents.
■ SPRAYABLE COATING APPLICATIONS
■ TWO COMPONENT, 100% SOLIDS SYSTEMS
■ 1:1 VOLUME MIX RATIO, WIDE FORMULATION LATITUDE
■ FAST REACTIVITY AND CURE WITHOUT A CATALYST
■ RELATIVELY MOISTURE AND TEMPERATUREINSENSITIVE DURING APPLICATION
■ EXCELLENT PHYSICAL PROPERTIES
■ HIGH THERMAL STABILITY (UP TO 175° C)
■ Tensile strength up to 28 MPa (4000 psi)
■ Shore Hardness A30 to D80
■ Elongation up to 1200 %
■ Tear strength up to 127000 N/m (725 pli)
■ 100% Modulus up to 14 MPa (2000 psi)
■ 300% Modulus up to 17 MPa (2500 psi)
CH2
OCN NCO
4,4'-MDI
CH2
OCN
NCO
2,4'-MDI
Aromatic-Based Systems
Aliphatic-Based Systems
H3CCH3 CH3
NCO
NCO
IPDI
CHH2N CH2
CH3
OCH2
CHNH2
CH3
x
x
y
z
x + y + z = ~81
HC
CH2[OCH2CH(CH3)]NH2
CH2[OCH2CH(CH3)]NH2
[OCH2CH(CH3)]NH2
JEFFAMINE® T-5000
Product x
JEFFAMINE D-400 5-6 JEFFAMINE D-2000 32-34
NH2
NH2
CH2
CH3
CH2
H3C
H3C
ETHACURE® 100
NHHN
H3CCH3 CH2
CH3CH2
H3C
UNILINK ® 4200
NH2
NH2
S
SH3C
CH3
H3C
ETHACURE® 300CLEARLINK ® 1000
NH
H3C CH2
CH3
HN
CH3CH2
H3C
SYSTEM TYPE: aromatic or aliphatic
UREA DENSITY INDEX (UDI): directly related to %NCO value of prepolymer
PREPOLYMER TYPE: isocyanate type, isomer distribution, and polyol (polyetheramine) composition can greatly affect overall elastomer properties
INDEX: can be used to help overcome brittleness and extend working time
CROSSLINK DENSITY: can affect brittleness, permeability, and chemical resistance
SECONDARY AMINE CONTENT: modulates system speed
■ Component Viscosity: <2000 cps (at RT) If too high: pump cavitation may occur
If mismatched: large pressure differential may exist
along with poor mixing
■ Operating Pressure: >138 bar (2000 psi) If too low: poor mixing and loss of spray
pattern may occur.
■ System Temperature: 60-80C (150-170F) If too low: poor mixing and loss of spray
pattern may occur.
ISOCYANATE COMPONENTISOCYANATE COMPONENTISOCYANATE COMPONENTISOCYANATE COMPONENT
15.4% NCO MDI-Based
Quasi-Prepolymer 100%
RESIN COMPONENTRESIN COMPONENTRESIN COMPONENTRESIN COMPONENT
JEFFAMINE® D-2000 57.7%
JEFFAMINE® T-5000 5.3%
ETHACURE® 100 18.6%
UNILINK ® 4200 18.6%
Index: 1.05 Volume Ratio: 1:1
Gel Time: 7.0 sTack-Free Time: 12.5 s
Hardness: D51Tensile Strength: 14.7 MPa
(2128 psi)Elongation: 529 %Modulus, 100%: 7.1 MPa
(1027 psi)Modulus, 300%: 10.1 MPa
(1471 psi)Tear Strength: 79846 N/m
(456 pli)
ISOCYANATE COMPONENTISOCYANATE COMPONENTISOCYANATE COMPONENTISOCYANATE COMPONENT
20.4% NCO MDI-Based
Quasi-Prepolymer 100%
RESIN COMPONENTRESIN COMPONENTRESIN COMPONENTRESIN COMPONENT
JEFFAMINE® D-2000 22.0%
JEFFAMINE® D-400 26.0%
JEFFAMINE® T-5000 10.0%
ETHACURE® 100 27.0%
UNILINK ® 4200 15.0%
Index: 1.10 Volume Ratio: 1:1
Gel Time: 2.5 sTack-Free Time: 4.0 s
Hardness: D70Tensile Strength: 24.3 MPa
(3522 psi)Elongation: 73 %Tear Strength: 125372 N/m
(716 pli)
IsocyanateIsocyanateIsocyanateIsocyanate
15.4% NCO MDI-Based 100%
Resin BlendResin BlendResin BlendResin Blend
JEFFAMINE® D-2000 51.4%
JEFFAMINE® T-5000 10.3%
ETHACURE® 100 9.5%
UNILINK ® 4200 20.6%
TIOXIDE ® TiO2 8.2%
INDEX: 1.30 VOLUME A/B: 1:1
WORKING TIME: ~2 min
POLYUREA IS NOT A MIRACLE COATING!!!
■ The appropriate polyurea elastomer system must be selected for the given application.
■ Even the best suited elastomer system will fail without proper substrate preparation.
POLYUREA TRIGGERMANSINCE 1985
CHIP EMERSONCHIP EMERSON RICHARD ROMERORICHARD ROMERO
