ADDITIVES TO IMPROVE OPEN-TIME AND FREEZE-THAW CHARACTERISTICS OF WATER-BASED PAINTS AND COATINGS

摘要

Waterborne coatings are described having an acceptable balance of properties both during the storage of coating, application and drying. The period in which irregularities in a freshly applied coating can be repaired without resulting in brush marks is referred to as the open time. Aqueous coatings generally employ dispersed high molecular weight polymers as binders. These binders often provide short open times when the coating is dried since the dispersed polymer particles tend to be immobilized quickly in the edge region of an applied coating. As a result, the viscosity of the coating increases rapidly, which leads to a limited window of workability. The instant invention provides additives that are not volatile but that will extend the time that the film is malleable after after it is applied without interfering with other attributes, such as the resistance of the coating to freezing while in the can prior to application.

主权项

1. A coating composition comprising: (a) at least one latex polymer; (b) water; and (c) at least one open time and freeze-thaw additive in an amount effective to increase the open time and freeze thaw properties of the coating composition the additive having the structural formulawherein n=2, x=10-12, y=0-10, z=0-10 and t=0-10, BO denotes a moiety derived from butylene oxide and SO denotes a moiety derived from styrene oxide and R is hydrogen or a C1-C22 alkyl group and wherein the additive is present in an amount greater than about 0.5% by weight of the polymer.