| Résumé : |
The introduction of a water-based equivalent to CAB rheology modifers offers considerable cost savings and performance advantages for manufacturers of water-based coatings. The author shows how CMCAB works.
For over 40 years cellulose acetate butyrates (CABs)have been used to modify the rheology and to improved hardness to solvent-based coatings.
However, as pressure on released VOCs has increased, the use of water-based systems have, in recent years, become more important. It has been estimated that around 50% of the OEM automotive basecoats applied in Western Europe use an aqueous coating basecoat formulation.
Automotive refinish paints, industrial metal, wood, a,d plastic coatings are also being pressured into the water-based route and much development is being directed into this area.
Water-based coatings, however, suffer from several disadvantages compared to their solvent-based precursors. Substrate wetting arising from water's high surface tension, its slow drying rate, and the susceptibility of its evaporation rate to changes in relative humidity, all contribute to difficulties in maintaining constant properties in the appearance and application of water-based coatings can be duplicated in a variety of water-based systems with carboxymethylcellulose acetate butyrate (CMCAB). |
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New applications for CAB in POLYMERS PAINT COLOUR JOURNAL - PPCJ, Vol. 192, N° 4452 (05/2002)
