Roy Tess Award Cliff Schoff. Delayed (Latent) Catalysis in Coatings Werner J. Blank Consultant

Transcription

1 Roy Tess Award Cliff Schoff Delayed (Latent) Catalysis in Coatings Werner J. Blank Consultant Antoine Carroy, Kurt Dietliker, Tunja Jung, Caroline Lordelot Ciba

2 Why Delay Latent catalyst Delayed catalyst Stabilized Before Application Improved Pot life Improved Stability Lower Losses After Application Controlled cure speed Improved flow leveling

3 Crosslinking Mechanism CRSSLIKER MELAMIE ISCYAATE EPXY SILXAE USATURATI MICHAEL ADDITI Catalyst Acid Base, Metal Base, Acid (cationic) Base, Acid, Metal Free Radical Base

4 Applications Aerospace 2K Automotive Topcoats, EM (Amino), Refinishing 2K Coil Coating Amino Resin Maintenance Epoxy-amine Powder Coating Waterborne 2K

5 ACTIVATI F CATALYST TRIGGER PTLIFE STABILITY EQUILIBRIUM MIXIG HEAT MISTURE XIDATI RADIATI UV X-LIKIG REACTI

6 Catalyst Delay Blocking Catalysts In-situ Catalyst Formation Physical-Mechanical

7 Photoinduced Catalyst: Principals o Arrhenius rate control Thermally stable catalyst Photocleavage: very fast Blocking Catalysts In-situ Catalyst Formation Photoactive blocker Acid catalyst Sulfonium Base catalyst Iodonium Free radical UV

8 Catalyst Delay Blocking Catalysts Evaporation Reaction Thermal decomposition In-situ Catalyst Formation Thermal decomposition of precursor Hydrolysis Reaction xide-salt Thermal Reaction xidation Rearrangement

9 Catalyst Delay Blocking Catalysts Acid-Base Base-Acid Metal Chelate Metal (Acid-salt( Acid-salt) Superacid-Quaternary Amine Superacid-Iodonium, Sulfonium (Photo)

10 10 Amine Blocking of Acid Catalyst, ptsa HMMM crosslinked polyol 8 Rate of Cure Boiling Point, ºC

11 Wrinkling

12 10 Amine Blocking of Acid Catalyst, ptsa pka Amine, Formaldehyde Reaction Rate of Cure TEA IPA DIPA DMEA pka-value

13 1000 REACTIVITY vs. TEMPERATURE Bis A epoxy Amine catalyzed Gel Time. min /T DBU SA-1 SA-501

14 nium Salt Photoinitiators: Latent Superacids I PF 6 - CH 3 Curing of epoxides, oxetane & vinyl ethers in coating and ink applications H 3 C CH 3 Superacid R 3 UV PF 6 - R 2 S R F F H + F P F + F F non-nucleophilic 0.3 Iodonium Sulfonium Thioxanthones R 2 Abs. 0.2, R 2 = H, C 6 H 4 -S-, R 2 C 6 H 4 -S-, R 3 C 6 H 4 -S Wavelength, nm

15 Catalyst Delay In-situ Catalyst Formation Sulfonic acid ester Thermal, Hydrolysis, Photo Amines Thermal Photo Generation Metal catalysts Hydrolysis xides reaction Thermal xidation Rearrangement

16 In-situ Catalyst Formation: Sulfonic Acid Ester Thermal - Hydrolysis S R C H S R 3 = Alkyl, ß-hydroxyalkyl R 3 = Phenyl Photoacid Generation S R 3 Tunable H S R 3 C Deep UV to Visible R 2, R 2 : tunig of the chromophore, thermal stability and solubility R 3 : tuning of acid strength/diffusion properties thermal stability

17 Photoresist Technology UV-Lamp Positive Exposure Mask Resist Image Layer Developing egative Etching Stripping (Photoresist) Substrate

18 In-situ Catalyst Metal Catalysts Formation Hydrolysis 30 Triphenylbismuth Catalyst (0.09%) HDI-Trimer/n-Butanol R-CH 168 hrs. Reaction C, % Hours R-CH 24 hrs. R-CH 0 hrs. TP 3 Bi

19 In-situ Metal Catalyst Formation Reaction + H Bi(RC) 2 - H 3 Bi(H) 3 + RCH 2 Bi(RC) 3 Polyether MDI Elastomer Bi ct. 1/5 mol WATER Viscosity, Poise Days 2 Days 7 Days Time, minutes

20 In-situ Metal Catalyst Formation Reaction R 3 R 3-2 Sn Sn R 3 R 2 R 2 Heat R 2 R 3 Tetraorganostannanes anti β-elimination bis(acyloxy)dialkylstannanes R 2 Sn Sn R 2 1/2 2 R 2 Sn R1 Sn R1 R 2 tetraalkyldistannanes distannoxanes B. Jousseaume,. oiret, M. Pereyre and A. Saux, rganometallics, 13, (1994). B. Jousseaume,. oiret, M. Pereyre, M. Franc and M. Petraud, rganometallics, 11, 3910 (1992).

21 In-situ Base Catalyst Formation Reaction R 2 H R R-C + R 2 H H H C C + H H H +

22 In-situ Photoinduced Base Generation of Amidine Double Bond pka= 8.96 ± 0.20 H CH 3 CH 3 R 2 S hν PLA-1 PLA-2 ITX H Absorban pk a = 12.7 R Wavelength, nm

23 Base Catalyzed Epoxy Reactions R' Many bases can catalyze the reaction of an epoxy group with a functional group R' R H R SH Reaction rate depends on the structure of the epoxy, the reactant and the amine catalyst. pka value does not determine reaction rate. R H R H 2

24 Thiol/Epoxy System: PL-DB catalysis S H H H S S H S H S H H S H S S S S Room Temperature Curing

25 360 Thiol/Epoxy System: Reactivity Coating applied onto glass plate at 70 µm m thickness Byk recorder (12hrs. cycle) after UV exposure (5 m/min. under 2 Hg lamps 100W/cm) Tack-free time (minute) >12 hrs. Without UV With UV 0 o Cat DB 0.5 % DB 0.2 % PLA-1 1.9% + BP 1.9 % PLA-2 1.9% + BP 1.9 %

26 Base Catalyzed Michael Addition Reactions R' H 2 C R R" R' = CH 3 pka R pka 13.0 R-SH pka 10.5

27 Base Catalyzed Isocyanate Reactions R' H 2 C R' = CH 3 pka R pka 13.0 R-C R" R-H pka 17.0 R-SH pka 10.7 H-H pka 15.7

28 Delayed Catalysis in Coatings Essential for Potlife Application Characteristics Film Appearance Photo Catalysis ew Technology Platforms Wide Variety of Crosslinking Mechanisms accessible for radiation curing

29 Acknowledgment Slide 13 Trends in Controlling Reactivity in Epoxy Formulation SPI publications Peter Lucas ERDI Conference Publications 1986 Air Products Slide 19 Private communication with J. Florio, Ram Subrayan King Industries Slide 20 Air Activated rganotin Catalysts for Silicone Curing and Polyurethane Preparation B. Jousseaume,. oiret, M. Pereyre and A. Saux, rganometallics, 13, (1994). B. Jousseaume,. oiret, M. Pereyre, M. Francès and M. Petraud, rganometallics, 11, 3910 (1992).