Static-Mixing Laboratory TechniquesFor Aliphatic Polyurea Coatings

David W. House, Dejan Ilijevski, Ray Scott, and John Leon

Presented at the Polyurea Development Association

December 1, 2000

A Typical Formulation for a Sprayed,Aliphatic Polyurea Coating

A-Side: Isophorone diisocyanate

JEFFAMINE D-2000

JEFFAMINE D-2000

JEFFAMINE T-5000

Curative(s)

B-Side:

NCO

NCO

H2N R1 NH2

NH2

R2

R2 R2

NH2H2N

R1

R1 NH2R1H2N

Low molecular weightpolyamine(s)

Benefits of Polyurea Coatings

* Improved physical properties* Very fast cure time - fast turnaround time* Fast physical property development (24h)* Virtually unaffected by moisture* Essentially unaffected by ambient temperature* Do not require catalyst* Better thermal stability

Challenges

* Very short pot life* High formulation viscosity

- Effective mixing- Application and adhesion to substrate- Surface uniformity

Solution

* Specialized equipment* Formulation development

High-Pressure, Impingement Mixing

* Handles pot lives of 2+ seconds* Heated components (160-170 oF)* High pressures (2000-3000 psi)* Uses spray gun to continuously deliver the

atomized formulation* Component volumes in gallons* Excellent in field use (large-scale)

High-PressureImpingement Mixing

Iso Resin

Challenge

* Lab-scale formulation development

Solution Requirements

* Screen large number of formulations in a short time* Mimic field equipment (impingement mixing)* Handle the very fast reaction kinetics

- Equipment size- Component volumes- Change-over time

Static Mix Gun Assembly

Static (Motionless) Mixing

* Uses extrusion to static mix the componentsand a draw down knife to spread the coating

* Low pressures (about 80 psi)* Room temperature and higher* Component volumes in grams* Fast, simple clean-up (disposable cartridges)* Quick screening of many different formulations

* Inexpensive (equipment and chemicals)* Small, uses minimal lab space* Uses same basic formulation parameters as

those used in impingement mixing* Technique is easy to learn* Handles pot lives of 10+ seconds

Coatings Made Using Impingement Mixingversus Static Mixing

Clearlink 1000

• Clear, colorless liquid• Equivalent Weight 161• Specific Gravity 0.90 at 68oF (20oC)

• Ames Test Nonmutagenic• LD50 (acute oral, rat) 482 mg/kg

Cycloaliphatic Secondary Diamine

• Viscosity 36 cSt at 100oF (38oC)• Pour Point -44oF (-42oC)• Flash Point (PMCC) 325oF (163oC) min• Vapor Pressure < 1 mm Hg at 68oF (20oC)

Comparison of Static Mixing to Impingement Mixing

Impt Static StaticFormulation Mixing Mixing Mixing

A-SideDesmodur I (%) 45 44.6 39.2JEFFAMINE D-2000 (%) 55 55.4 60.8

% NCO 14.8 14.5 12.2Index 105 105 105

B-SideJEFFAMINE D-2000 (%) 32.2 35.0 49.3JEFFAMINE T-5000 (%) 8.6 15.2 12.7Clearlink 1000 (%) 46.8 49.8 38.0TiO2 (%) 12.4 0.0 0.0

Comparison of Static Mixing to Impingement Mixing

Impt Static StaticProcessing Mixing Mixing Mixing

Volume Ratio (A/B) 1.00 1.00 1.00Weight Ratio (A/B) 0.96 1.08 1.08

Spray/Cartridge Temp. (oF) 140 73 73Coating Thickness (mil) 41 31 34

Pot Life (sec) 9 ~ 15 < 20Tack-Free Time (min) --- 3.5 15

Comparison of Static Mixing to Impingement Mixing

Impt Static StaticPhysical Properties Mixing Mixing Mixing

Hardness, inst. (Shore D) 43 60 48

Tensile Strength (psi) 2820 4060 4170100% Modulus (psi) 1350 1560 1040Elongation (%) 500 530 600

Tear Resistance (pli) 500 630 490Tear Prop. Resist. (pli) 525 550 400

Resilience (%) 40 41 40

Comparison of Static Mixing to Impingement Mixing

Impt StaticFormulation Mixing Mixing

A-SideDesmodur I (%) 45 39.6JEFFAMINE D-2000 (%) 55 60.4

% NCO 14.8 12.4Index 105 105

B-SideJEFFAMINE D-2000 (%) 40.7 50.7JEFFAMINE T-5000 (%) 9.9 12.8VESTAMIN IPD 7.7 2.0 Clearlink 1000 (%) 30.8 34.5

Comparison of Static Mixing to Impingement Mixing

Impt StaticPhysical Properties Mixing Mixing

Hardness, inst. (Shore D) 42 48

Tensile Strength (psi) 2510 4340100% Modulus (psi) 1200 1075Elongation (%) 470 600

Tear Resistance (pli) 415 500Tear Prop. Resist. (pli) 345 390

Resilience (%) 39 45

Volume Ratio (A/B)Weight Ratio (A/B)Coating Thickness (mil)

1.001.0334

1.001.0533

1.001.0633

1.001.0836

1.001.0928

A-SideDesmodur I (%)

JEFFAMINE D-2000 (%)

% NCOIndex

26.773.3

7.0105

33.166.9

9.7105

38.161.9

11.8105

42.157.9

13.4105

45.055.0

14.8105

B-SideJEFFAMINE D-2000 (%)JEFFAMINE T-5000 (%)

Clearlink 1000 (%)

36.147.916.0

29.142.628.4

23.438.338.3

18.834.846.4

15.031.953.1

Effect of Clearlink 1000 Level on Polyurea Coatings

Pot Life (sec)Tack-free Time (min)

< 302.5

< 304.0

< 306.0

< 309.0

< 30> 10

Hardness, instant (Shore D) After 10 sec (Shore D)

17 (56A)9 (41A)

31 (79A)20 (68A)

4636

5445

6050

0

10

20

30

40

50

60

70

10 20 30 40 50 60

Clearlink 1000 Level, %

Har

dn

ess,

Sh

ore

DEffect of Clearlink 1000 Level on Hardness

56A

79A

95A

41A

68A

88AInstantAfter 10 sec

0

500

1000

1500

2000

2500

3000

3500

10 20 30 40 50 60

Clearlink 1000 Level, %

Ten

sile

Str

., p

si

0

100

200

300

400

500

600

700

800

900

1000

Elo

ng

atio

n, %

Effect of Clearlink 1000 Level on Tensile Strengthand Elongation

0

100

200

300

400

500

600

10 20 30 40 50 60

Clearlink 1000 Level, %

Tea

r S

tren

gth

, pli

Resistance

Propagation

Effect of Clearlink 1000 Level on Tear Strength

Formulations for the Chain Extender Level Study

Isocyanate Component

VESTANAT IPDIJEFFAMINE D-2000

%NCO

A

4555

14.8

B

4555

14.8

C

4555

14.8

D

4555

14.8

E

4555

14.8

Resin Blend

JEFFAMINE D-2000JEFFAMINE T-5000VESTAMIN IPDAClearlink 1000Ti02

48.1714.9622.830.0

10.64

48.6212.1516.5711.6011.05

45.6110.0111.9621.0211.12

40.669.897.6930.7710.00

32.188.600.00

46.7812.38

Index = 105, Iso/Resin Ratio = 1.00:1.00

Effect of Clearlink 1000 Levelon Physical Properties

0

10

20

30

40

50

60

Har

dn

ess,

Sh

ore

D

0 sec 10 sec

12 pbw 21 pbw 31 pbw 47 pbw

0

500

1000

1500

2000

2500

3000

Tensile Str.

Ten

sile

Str

., ps

iEffect of Clearlink 1000 Level

on Physical Properties

0

100

200

300

400

500

Elong. Tear R.

Elo

ng, %

/Tea

r, p

li

Pbw Clearlink 1000: 12, 21, 31, 47.

Effect of Isocyanate Index on Physical Properties

Isocyanate Index 0.95 1.00 1.05 1.10 1.15 1.20

Isocyanate Component

VESTANAT IPDIJEFFAMINE D-2000

%NCO

4555

14.8

4555

14.8

4555

14.8

4555

14.8

4555

14.8

4555

14.8

Resin Blend

JEFFAMINE D-2000JEFFAMINE T-5000VESTAMIN IPDAClearlink 1000

43.2115.4315.4325.93

44.7015.5913.5126.20

45.8316.6712.5025.00

46.6717.7811.1124.44

47.2518.689.89

24.18

48.6519.469.73

22.16

Iso/Resin Ratio = 1.00:1.00

0

500

1000

1500

2000

2500

3000

Tensile Str.

Ten

sile

Str

., ps

iEffect of Isocyanate Index on Physical

Properties: ~25 pbw CL1000, 41 Shore D

0

100

200

300

400

500

600

700

800

Elong. Tear R.

Elo

ng, %

/Tea

r, p

li

Index: 95, 100, 105, 110, 115, 120

QUV Weatherometer Study2000 Hours Exposure to a UV B-313 Bulb

0

500

1000

1500

2000

2500

Un

its

Tensilepsi

Elong. % Mod100%

Mod300%

Tear pli

Unexposed 2000 hr QUV

Elcometer Adhesion Strengthof a Clearlink 1000-Based Polyurea Coating

0

200

400

600

800

1000

1200

1400

Ad

hes

ive

Str

., p

si

Concrete Smooth Steel Blasted Steel 2 mil Blasted

100%CF

100%AF

85%CF

Conclusions

* A new laboratory technique has been developed for screeningpolyurea and polyurethane impingement-mixed formulations

* The static mixing method is fast, easy to learn, inexpensive,requires no specialized equipment or lab preparation, andneeds minimal space.

* The technique mimics the physical properties of coatingsmade using impingement mixing and is useful forestablishing trends

Summary

The use of Clearlink 1000 in polyurea coatings...

* Produces light-stable coatings* Increases working time* Improves adhesion to substrate

Significantly increases:* Hardness* Tensile strength* Elongation* Tear Strength

Acknowledgement

Aureliano Perez, Jr. and Kenneth M. Hillmanof Huntsman Corporation, USA

“It just sprays better”