The instant invention relates to compositions comprising polyether modified silicone having at least of a butyl or an acetyl end cap. The instant compositions can be employed in a wide range of compositions including compositions used as de-aerators for reducing, if not eliminating, air bubbles in airless and air assisted spray applied coatings.
Air bubbles and foams in coating formulations are harmful to the coating finish because the bubbles can form and leave craters, pinholes and other surface defects which are undesirable. To control bubble formation, a defoamer or deaerator, can be added to the coating in order to prevent macrofoams or microfoams, respectively.
Foams are usually generated by the additives in the coating system, such as surfactants or emulsifiers, and also by the coating application technique. For example, airless and air assisted spray applications tend to trap air into the coating as the viscosity and thickness of these coatings are usually greater than those applied by conventional spray.
Certain conventional compositions are described in U.S. Pat. Nos. 3,402,192; 3,746,653 and 4,711,714. With respect to U.S. Pat. No. 3,402,192, the primary object of this patent is to provide polyoxyalkylene siloxane copolymers which are useful as surfactants and as emulsifying agents. Another object is to provide a stable nonhydrolyzable surfactant for polyurethane foams which does not give a pneumatic effect in the foam. A further object is to provide superior surfactants for the production of polyurethane foams which exhibit excellent solubility in water and excellent stability in mixtures with polyglycols, amines and fluorocarbons. There is no disclosure of coating compositions or defoaming or deaerating coating compositions.
U.S. Pat. No. 3,746,653 relates to a composition of foam control agent particularly useful in jet dyeing of textiles. The glycol or polyoxyalkylene unit of siloxane glycol copolymer is terminated or capped by the A group. There is no disclosure of the specific nature of this group or any utility in coating compositions or defoaming or deaerating coating compositions.
U.S. Pat. No. 4,711,714 relates to water-insoluble Polyoxyalkylene graft copolymers as anti-foam agents for reducing foaming in crude oil/gas separators. There is no disclosure of coating compositions or any utility in coating compositions or defoaming or deaerating coating compositions.
The disclosure of the previously identified patents is hereby incorporated by reference.
There is a need in this art for a defoamer or deaerator for use in coating compositions.