Fast Curing Polyurea Sealants: Controllable Reactivity ...

1 Fast Curing Polyurea Sealants: Controllable Reactivity with commercially available Secondary Amines Dr. Jay Johnston Bayer Material Science Presented at a meeting of the Thermoset Resin Formulators Association at the Hyatt Regency Savannah in Savannah, Georgia, September 10 11, 2007. This paper is presented by invitation of TRFA. It is publicly distributed upon request by the TRFA to assist in the communication of information and viewpoints relevant to the thermoset industry. The paper and its contents have not been reviewed or evaluated by the TRFA and should not be construed as having been adopted or endorsed by the TRFA.

2 CAS September 2007 Page # 1. Fast Curing Polyurea Sealants: Controllable Reactivity with commercially available Secondary Amines CAS September 2007 Page # 2. Why Does the Market Use Polyurea Sealants? Fast Reactivity Fast return to service used on airports runways Can cut flush to surface within 5 to 20 minutes Insensitivity to atmospheric and substrate moisture Prevents spalling of concrete into joint Cures at low temperatures used in refrigerators Tunable physical properties 1 to 1 volume ratios - easy to meter Reduced VOCs versus other sealants no VOCs possible Good adhesion to most substrates adhesion promoters Plasticizer free formulations CAS September 2007 Page # 3.

3 Target Physical Properties of Polyurea Sealants Gel time 5 to 20 minutes optimum 10 minutes Longer than 15 minutes the sealant may foam Hardness Shore A 85 to 90 preferred Tensile strength optimum 1500 psi not stronger than concrete Maximum elongation As high as possible Tear resistance 250 pli or higher 100% modulus as low as possible Low temperature cure CAS September 2007 Page # 4. Current Polyurea sealant Formulations Primary amines react too rapidly for static mix tube applications 4,4'-SBMDA developed as slower reacting amine Secondary diamines react slowly Polyurea sealants possible Aromatic structure N N.

4 H H. 4,4'-SBMDA. CAS September 2007 Page # 5. Typical Starting Point Formulation for Polyurea Sealant1. JEFFAMINE D-2000 4,4'-SBMDA Titanium dioxide TINUVIN 292 TINUVIN 1130 IRGANOX 1135 Typically applied 1 to 1 by volume with a 14-16% NCO. prepolymer 1 Chemical Suppliers are on the last slide CAS September 2007 Page # 6. Properties of 4,4'-SBMDA-based Sealants Used BAYTEC MP-160 and a 14% NCO. prepolymer 14% NCO prepolymer was blend of BAYTEC MP-160 and DESMODUR E. 210. CAS September 2007 Page # 7. Gel Time of Polyurea Caulk 6.

5 5 BAYTEC . MP-160. 4 Blend Gel Time (m). 3 Gel Time 2. 1. 0. 728B-16% 735A-14%. CAS September 2007 Page # 8. Hardness of Polyurea Caulk 100. BAYTEC MP-160. 98. 96. Shore A Hardness 94. Blend 92. 90 Shore A. 5 sec 88. 86. 84. 82. 80. 728B 735A-14%. CAS September 2007 Page # 9. Tensile Strength of Polyurea Caulk 3000 Too strong for most caulk applications Concrete will break before sealant 2500 BAYTEC MP-160. Tensile Strength (psi). 2000. Tensile 1500 100%. Strength is adequate 200%. 1000 300%. Blend 500. 0. 728B-16% 735A-14%.

6 CAS September 2007 Page # 10. Elongation of Polyurea Caulk 455 Good Elongation BAYTEC . MP-160. 450. 445. Elongation (%). 440 Elongation 435. Blend 430. 425. 728B-16% 735A-14%. CAS September 2007 Page # 11. Tear Resistance of Polyurea Caulk Good Tear Resistance 600. BAYTEC . 500 MP-160. Tear Resistance (pli). 400. Blend 300 Tear 200. 100. 0. 728B-16% 735A-14%. CAS September 2007 Page # 12. Evaluation of Aspartic Esters in Polyurea sealant Formulations Objective Evaluate aspartic ester amines in sealant formulations Reactivity of amines DESMOPHEN NH 1220 very fast DESMOPHEN NH 1520 very slow DESMOPHEN NH 1420 close Blends of DESMOPHEN NH 1520/DESMOPHEN.

7 NH 1420 to adjust Reactivity CAS September 2007 Page # 13. Polyaspartic Esters DESMOPHEN NH-1520 NH-1420 NH-1220. % Solids 100 100 100. Eq Wt 291 277 229. at 25 C (cps) 1500 1500 150. Reactivity low mid high Amine cycloaliphatic cycloaliphatic linear O O. RO OR. RO X OR. N N. O H H O. CAS September 2007 Page # 14. Reactivity of Aspartic Ester Blends 80. 100 % DESMOPHEN NH 1420. 14 % NCO Prepolymer 100 %DESMOPHEN NH 1520. 70 No JEFFAMINES in B-side 60. Gel Time (m). 50. 40. 30 Gel Time 20. 10. 0. 0 25 50 75 100. Desmophen NH 1520 (%).

8 CAS September 2007 Page # 15. Effect of Jeffamine on Aspartic Ester Formulations 200 JEFFAMINE Free Technically possible to make 175 ultra slow Polyurea caulks, 150 But .. G el Time (m). 125 0 % 1520. 25 % 1520. 100. 50 % 1520. 75. 100 % 1520. 50 JEFFAMINE hides the true Reactivity of the aspartic esters 25. 0. 5 10 15 20. CAS September 2007 Page # 16. NCO (%). Optimization of Properties and Process Molecular sieves increases window 100. 75. Foamy 0. NH 1520 (%). 25. 50 50. Shorter Window 75. Gel 100. 25 Times <5M. Brittle 0.

9 0 2 4 6 8 10 12 14 16 18. CAS September 2007 Page # 17. NCO (%). Index Study Determine the effects of index on the physical properties of Polyurea sealants. Base study on DESMODUR E 210 (commercial product). Try to optimize properties with the commercial isocyanate CAS September 2007 Page # 18. Gel Time of Polyurea Caulk Good gel times 95. 100. 9 105. 107. Gel Time (m). Gel Time 110. 8. 763H 763E 763F 763A 763G. CAS September 2007 Page # 19. Tensile Strength of Polyurea Caulk 1000. 95 Adequate tensile strength 107. 900 100 105.

10 800 110. Tensile Strength (psi). 700. 600 Tensile 500 100%. 200%. 400. 300%. 300. 200. 100. 0. 763H 763E 763F 763A 763G. CAS September 2007 Page # 20. Elongation of Polyurea Caulk 600. Good elongations 107 110. 105. 500. 100. 95. 400. Elongation (%). 300 Elongation 200. 100. 0. 763H 763E 763F 763A 763G. CAS September 2007 Page # 21. Tear Resistance of Polyurea Caulk 300. 95. 250 105. 100. 110. Tear Resistance (pli). 107. 200. 150 Elongation 100. 50. 0. 763H 763E 763F 763A 763G. CAS September 2007 Page # 22. Properties of Optimized Desmodur E.