1. New Amine Curatives for Polyurea Coatings and Caulkings
Paul Wiggins, Judith Orgad and John Lee
In this presentation I will share with the work that we have been doing in the lab in developing new amine curatives and testing them in polyurea systems.
Albemarle Corporation
Process Development Center
Gulf States Road
Baton Rouge, LA 70805
(225)
Polyurethanes 2005 Technical Conference and Trade Fair
October 17-19, 2005

2. Curative Growth Opportunities
Hot Cast Polyurethane
Good Dynamic Properties
Optically Clear Elastomers
Coatings
Polyurea Spray Coatings
Polyurethane Coatings
Room Temperature Cast Polyurethane
Tire fill
RIM
Run Flat Tire
Here I will share we you the opportunities that have lead us to develop new curatives.
In hot cast polyurethane, Ethacure 100 can be used to make small wheels or castors but it is too fast to make larger wheels. Ethacure 300 has the correct cure profile for larger wheels but does not have the dynamic properties. There is an opportunity for a slower curative with good dynamic properties. Presently small optically clear elastomers can be made as shown here in this gas mask but the system is too fast to make larger castings. There is a need for a slower curative that will provide an optical clear elastomer.
In the coatings area Ethacure 100 is used in polyurea spray coating but its speed makes it difficult to process when it is the sole curative so a slower curative would be welcomed by the formulators. Ethacure 300 has seen limited use in polyurethane coatings because of poor UV resistance so a slower curative would good UV resistance is needed.
In room temperature cast the use of amine curative are limited in tire fill because they are too fast and a slower curative would allow more to be incorporated into the formulation and provide better properties.
In RIM applications such as the run flat tire, a slower curative would allow the designer of the parts more latitude in designing more complex parts.

3. Goal
To provide cure speed flexibility in selecting amine curing agents for polyurea and polyurethane applications.
To test rapidly.
To compare against standard Ethacure® 100 base formulations.

4. Baseline Formulation
The formulation below is a standard polyurea system containing Albemarle’s Ethacure® 100 curative. We will evaluate other curatives and curative blends against the properties obtained from this standard formulation.
Side A Component
Rubinate® 9480 MDI, 14.9 % NCO
Side B Components
Jeffamine® D-2000 polyether amine
66.1
Jeffamine® T-5000 polyether amine
5.8
Ethacure® 100 aromatic diamine
28.1

5. Processing
A MIXPAC DP pneumatic dispensing gun was used with the static mixers listed below:
The polyurea was extruded onto a steel plate and cured at room temperature for 2 weeks before physical property measurement.
Elements
I.D. EA 30
0.37”
MS 06-48 48
0.25”

6. Processing

7. Processing

8. Processing

9. Processing

10. Processing

11. Baseline Formulation Using Ethacure® 100 Curative
The Ethacure® 100 polyurea system is fast.
In a static mixer the viscosity increases rapidly making it a challenge to get adequate mixing.
Conditions were varied in order to improve the mixing and provide good physical properties.

12. Mixing Conditions and Gel Times
The effects of heating the A-side and B-side were tested.
At higher temperatures the viscosity was reduced making the residence time in the static mixer shorter but also shortening the gel time.
The most consistent results were obtained when the A-side and B-side were heated.

13. Physical Properties Temperature 25°C 50°C 66°C 67°C
Static mixer, units 30 48
Gel Time, sec 7
<2
Shore D hard., (0sec/10sec)
46/42
45/42
44/41
45/40
Tensile Str., psi
2100
2050
2250
2310
Elongation, %
330
350
320
370
Modulus (100%)
1300
1280
1360
Modulus (300%)
2040
2170
2030
Tear strength, pli
450
430
460

14. Key Market Needs – New Curatives
Cure speed versatility – curatives to meet needs of variety of end-user applications
Good properties – clarity, UV, strength
Low cost is critical in most applications
Good H&E product characteristics are needed for customer acceptance of new materials
In Conclusion
New materials are costly to introduce (H&E testing, etc.) – need good opportunities

15. Characteristics of Amine Curing Agents
Aromatics
Aliphatics
Color - +
UV Resistance
Physical Properties
Cost

16. Slower Reacting Curatives
Four new developmental curatives called XP-A, XP-B, XP-C and XP-D were evaluated.
XP-A, XP-B and XP-C are aromatic amines, while XP-D is an aliphatic amine.
Data on the performance of the commercially available Ethacure® 300 curative is also presented.
The Jeffamine® 2000 level in the standard formulation was adjusted to keep the volume ratio of the A-side to B-side at 1:1.

17. Physical Properties
Gel times of the polyurea formulations with the new curatives were longer than those with E-100 (Ethacure 100) while the tensile values were lower than those of E-100 system.
Curative
E-100
XP-A
XP-B
XP-C
XP-D
E-300
Gel Time, sec
<2 61 33 97 42
Shore D Hardness(0sec/10sec)
45/40
28/23
31/27
38/34
44/38
43/40
Tensile Strength, psi
2310
1060
1770
1960
2030
1530
Elongation, %
370
470
350
280
Modulus (100%)
1300
520
970
1045
990
1250
Modulus (300%)
800
1620
2070
1720 --
Tear strength, pli
460
240
320
300
440

18. Gel Time

19. Physical Properties

20. Physical Properties of Blends
E-100 was blended in a 1:1 weight ratio with the other curative in a polyurea formulation.
A balance of physical properties and gel time was obtained. XP-D gave the highest properties.
Curative
E-100
XP-A
XP-B
XP-C
XP-D
Gel Time, sec
<2 11 12 10 14
Shore D Hardness(0sec/10sec)
45/40
36/33
36/34
45/41
Tensile Strength, psi
2310
1740
2160
2530
2670
Elongation, %
370
330
290
340
390
Modulus (100%)
1300
1080
1310
1360
Modulus (300%)
2030
1650
2170
2280
2350
Tear strength, pli
460
400
520

21. Gel Time (sec)

22. Physical Properties

23. XP-D
It should be noted that XP-D is an aliphatic diamine and is a water white liquid.
It has a longer gel time than Ethacure 100.
It can be blended with the low color Ethacure 100-LC to produce a system with long gel times and good physical properties for optical clear parts.

24. Evaluation in Other MDI Systems
Rubinate 9480 is a lower viscosity, slower reacting MDI suited for fast reacting Ethacure It has a high level of 2,4’-isomer. It was used in all our formulations so far.
Rubinate 9009 which has a low 2,4’-isomer content and a high 4,4’isomer content was evaluated with the slower reacting curatives. It was too fast for E-100 in the static mixer.

25. Physical Properties
Higher tensile strengths were obtained with Rubinate 9009.
Formulation
E-300
/9480
/9009
XP-A
9009
Gel Time, sec 42 31 53 17
Physical Properties
Shore D hardness, (0sec/10sec)
43/40
59/52
29/20
50/44
Tensile Str., psi
1530
2430
920
2280
Elongation, %
280
170
420
130
Modulus (100%)
1250
2140
518
2080
Modulus (300%) --
770
Tear strength, pli
440
540
250

26. Conclusions
New experimental slower curing agents/blends have been developed to provide a slower curing system than the standard system containing only Ethacure 100 curative.
An aliphatic amine curative has been found that is slow enough to be used with an MDI prepolymer providing a slower gel time than Ethacure 100.
Rubinate 9009 formulations provided higher tensile strengths than the Rubinate 9480 for the slower curatives.

27. Conclusions (cont.)
Work is continuing with our patent pending process to produce other curatives to optimize cure rate and physical properties.
New amine curatives, both aromatic and aliphatic, have been developed within Albemarle. We are awaiting guidance from our H&E group as to the length and cost of testing these new materials prior to starting a sampling program.