Cyanoacrylate alkoxyalkyl

Using a more hydrophilic cyanoacrylate than the n-butyl and n-octyl cyanoacrylates that are presently used as nonabsorbable tissue adhesives — for this, alkoxyalkyl cyanoacrylates such as methox-... 

A more hydrolytically labile cyanoacrylate than the n-butyl, isobutyl, and n-octyl cyanoacrylates to yield polymers that, under facile hydrolysis of their ester group, produce water-soluble by-products and hence meet the minimum requirement for being an absorbable polymer — for this the alkoxyalkyl cyanoacrylates were chosen. 

A cyanoacrylate with a flexible side chain to yield a more pliable polymer than those of alkyl cyanoacrylate without compromising adhesive joint strength — for Ihis, alkoxyalkyl cyanoacrylates were selected to meet the minimum compliance required for the resulting polymer. 

Anyone who has used cyanoacrylates on a continuous basis in an area with poor ventilation is familiar with the pungent, irritating, acrylic-type odor. The relatively high vapor pressure of the cyanoacrylate monomers which contributes to the odor can also cause evaporation from uncured fillets the vapors precipitate as a white haze on surfaces adjacent to the bondline. On bright, decorative, or transparent parts this may be unacceptable, often requiring the use of an alternative adhesive. Good ventilation helps, but not universally. This has led to the development and marketing of alkoxyalkyl cyanoacrylate adhesives, which structurally are merely ethyl cyanoacrylates with methoxy or ethoxy... 

The fourth type of cyanoacrylates presented in Fig. 2 are the alkoxyalkyl esters. Methoxyethyl cyanoacrylate and methoxyisopropyl cyanoacrylate esters have all the desirable properties of the methyl, ethyl, and allyl cyanoacrylates, with the added advantage of low vapor pressure. As a result, these monomers have little or no odor, which makes them popular for use in environments where ventilation is a problem. The low vapor pressure also reduees the fogging of adjaeent parts so often seen with regular cyanoaerylates on damp days, a problem discussed in more detail below. 

Tbe lower esters of alkyl 2-cyanoacrylates (eg, methyl, ethyl esters) provide adhesives with excellent lap-shear strengths to a variety of different substrates (3). They are, however, brittle materials and generally require the addition of a rubber-toughening agent to improve peel strength and impact resistance (4). The low esters have pungent odors whereas the higher esters, in particular the alkoxyalkyl esters, are virtually odorless (3). 

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