Page 184 - Handbook of Adhesion Promoters

9

Selection of

Adhesion Promoters

for Different Products

9.1 ADHESIVES
A number of commercial adhesion promoters are suggested for the use in adhesives,
including Chartwell C-516.72.HR, C-523.72HRW, and F-505.2, Escorex 2173, Fancryl
FA-512AS, Geniosil GF 92 and 93, Priplast 3132, Silquest A-1106, Sipomer PAM 100,
200 and 4000, Uniplex 260, and Visiomer TMPTMA. They contain the following active
compounds: carboxyl/hydroxyl-, amino-, mercapto- silanes, aminopropylsilsesquioxanes,
dicyclopentenyloxyethyl acrylates, phosphate esters of polyethylene glycol
monomethacrylate, ethyl methacrylate phosphate, aromatic modified aliphatic hydrocar-
bon resin, and semicrystalline polyester diols.
Pressure sensitive adhesives were able to replace physical bonds destroyed by envi-
ronmental influences, such as aging and water attack by bonds reformed due to their rheol-
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ogy and high molecular mobility.
Aminopropylphosphonic acid was investigated as a short-chain bifunctional adhe-
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sion promoter for an aluminum alloy and an epoxy amine adhesive. Formation of ionic
bonds on the aluminum oxyhydroxide surface due to acid/base interactions resulted in a
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strong inhibition of this anodic de-adhesion process.
The binary combinations of adhesion-promoting (γ-aminopropyltriethoxysilane) and
non-adhesion-promoting (octadecyltrichlorosilane) silanes were patterned onto an oxide
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adherend surface of polyvinylbutyral. Adhesion depends on size, shape, and area ratio of
the silanes, in many cases resulting in a reduction of adhesion compared with that for a
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pure APS film, but in other cases producing enhancements of as much as 80%. The great-
est adhesion was achieved using square islands, 12 mm × 12 mm in size, surrounded by
1.5 mm wide borders. As the crack propagates through a heterogeneous surface, it will
blunt at the end of an adhesive patch, and it must re-nucleate at the start of the next adhe-
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sive domain.
An acetic acid content of 0.25 wt% acted as an adhesive promoter for ethyl 2-cyano-
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acrylate adhesive.
Degreasing, etching, plasma, grit-blasting, and silanization were the treatments used
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on the surface of alumina ceramics. The treatments removed organic contaminants from
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the alumina, resulting in a higher surface free energies.