Mildew-resistant Acetoxy-cure Silicone Sealant
This information reflects our best understanding of product composition in 2022.
This common product describes one-component silicone sealants containing a fungicide to make them resistant to mold and mildew. These sealants are composed of reactive siloxanes and silanes that cure upon contact with moisture in the air....
This common product describes one-component silicone sealants containing a fungicide to make them resistant to mold and mildew. These sealants are composed of reactive siloxanes and silanes that cure upon contact with moisture in the air. Structural sealants can be classified as acid-cure (acetoxy) or neutral-cure (alkoxy). Mold- and mildew-resistant silicone products are typically acetoxy sealants, though neutral cure products are available. Acetoxy cure sealants release acetic acid upon curing, giving them their characteristic vinegar smell. While acetic acid can be corrosive to some substrates, acetoxy cure sealants can still be used on a wide variety of substrates to prevent mold and mildew formation around fixtures. They are commonly used in damp environments such as locker rooms, lavatories, and can be applied to bathtubs, shower stalls, sinks, countertops, and other plumbing fixtures.
Acetoxy cure sealants tend to adhere better to substrates than neutral cure sealants, but some substrates may still require a primer. While not identified as common, some can contain fungicides based on arsenic. See the All Contents tab for details on all substances identified in mold- and mildew-resistant silicone sealants.