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A Colorless Epoxy Catalysts |
Hycat AO-3
A common problem with various epoxy cures is the tendency for the cured products to be colored due to the components in the formulation, sensitivity to elevated cure temperatures and the chemical interaction of the catalyst during the cure. Combine with this the requirements for catalytic latency and ease of use for component blending only adds to the quest for the ideal cure system. Hycat™ AO-3, produced by Dimension Technology Chemical Systems, Inc., achieves these goals of clear and colorless and fast cures when reacting anhydrides with diglycidyl ether of bisphenol A, diglycidyl ether bisphenol F and cycloaliphatic diepoxides. Other epoxides are expected to behave favorably in similar formulations. Commonly used catalysts do not give these desired results. For example, a large difference in color was observed comparing the use of different cure catalysts. In a typical formulation of diglycidyl ether of bisphenol F (DER 354) and methylhexahydrophthalic anhydride (Lindride 52D) with 2.0 % catalyst loading at 120°C there is a noticeable change in color or uniformity of cure when comparing Hycat™ AO-3 to tetrabutylammonium bromide (TBABr) or 1,8-diaza-bicyclo[5.4.0]undec-7-ene (DBU) and benzyldimethylamine (BDMA).
Additionally, Hycat™ AO-3 gave good cure time and hardness values.
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TBABr
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DBU
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BDMA
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Hycat™ AO-3
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Cure Time (min.)
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8-12
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8-12
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4-8
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12-16
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Hardness Test, Durometer Type D
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86
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88
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86
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89
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Again, when diglycidyl ether of bisphenol A (DER 332) was reacted with MHHPA (Lindride 52D) with 2.0 % Hycat™ AO-3 catalyst loading at 120ºC, a clear and colorless cure resulted. By contrast, using the catalysts TBABr, DBU, and BDMA resulted in highly colored cures or considerable voids throughout the cure.
And as before, the cure time and hardness was favorable.
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TBABr
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DBU
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BDMA
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Hycat™ AO-3
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Cure Time (min.)
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8-12
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8-12
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8-12
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12-16
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Hardness Test, Durometer Type D
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86
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87
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86
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89
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