Page 194 - Handbook of Adhesion Promoters

9.9 Coil coatings 187

9.9 COIL COATINGS

Coil coatings must be capable of curing at line speeds in excess of 50 m/min, withstand
1
forming processes, resist corrosion, and photodegradation for 25 years or more. Failure is
usually cohesive. The adhesive failure occurs in products of the lower end of the perfor-
1
mance. The level of adhesion promoter has a profound effect on durability both in the ini-
1
tial salt spray and humidity tests as well as on the wet adhesion.
The durable UV cured primer layers for coil coatings contain adhesion promoters. 2
The adhesion promoter, which has a chemical affinity for the metal surface, polymerizes
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with the resin and thereby anchors the cured primer layer to the metal surface. The pho-
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toinitiator is chemically bound to an adhesion promoter.
The methacrylate phosphonic esters (di(trimethylsilyl) 3-acryloyloxypropylphospho-
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nate) are used as adhesion promoters in coil coating. Similar to the previous invention
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they are combined with photoinitiators.
REFERENCES
1 Adhami, S; Abel, M-L; Lowe, C; Watts, JF, Surf. Interface Anal., 44, 1054-8, 2012.
2 Galbo, JP; Dong, Y; Galan, DA; Sitzmann, EV, US88367743, Basf SE, Feb. 5, 2013.
3 Craciun, L; Dong, Y; Polishchuk, O; Koenigsmann, K; Ho, BW, US8372516, Basf SE, Feb. 12, 2013.