▎ 摘　　要

NOVELTY - Coating composition, which, when coalesced, forms a water vapor permeable air barrier, comprises acrylic latex, 1-10 wt.% glycol ether and 0.25-5 wt.% humectant, the coating composition has a viscosity ranging from 5000-500000 centipoise, which is measured at 77 degreesF (25 degreesC) using a Brookfield HB viscometer equipped with Spindle 3 at 2.5 revolutions per minute, where an air barrier formed by the coating composition has a water vapor permeance greater than 1 permeance at 35 mil film thickness when measured at 77 degreesF. (25degrees C.) and 50% relative humidity, according to ASTM E96/E96M-16, Method B. USE - Coating composition for use in exterior sheathing panel of a building (claimed), wood, engineered wood, metal, concrete, CMU (concrete masonry unit), other waterproofing coatings and sealants, gypsum, and plastics. ADVANTAGE - The coating compositions should form crack-free coatings suitable for air barrier, and the formed coatings should preferably present desirable properties, such as good elongation and good water vapor permeability. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) a method of forming an air barrier on a substrate, which involves: i. applying a coating composition to a surface of the substrate, wherein the coating composition coalesces to form a water vapor permeable air barrier on the substrate; and (2) a substrate coated with an air barrier, the air barrier being formed by coalescing a coating composition on the surface of the substrate.