Sag resistant, formaldehyde-free coated fibrous substrate
AssigneeAWI Licensing LLC
InventorsLida Lu, Kenneth G. Caldwell
Life of this patent
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Abstract
The present invention relates to an improved formaldehyde-free coated fibrous substrate. The coating includes a crosslinked binder system which forms three dimensional networks when heat cured. After the coating is applied to the back of fibrous substrate and cured, the coating is capable of hygroscopic expansion which imparts excellent anti-sag properties. The coating is compatible with other coating systems with neutral or mild alkaline pH. The improvement being the binding system is neutralized with a volatile base so that it evaporates quickly so as not to hinder the cross-linking reaction.
Claims19
A method of manufacture of a sag-resistant building panel comprising
- applying a coating composition to a major surface of a substrate, the coating composition comprising:
- a polymeric binder comprising polyacrylic acid;
- a polyol crosslinker selected from the group consisting of diethanolamine, triethanolamine, glycerol, dextrose, sucrose, fructose, sorbitol, and combinations thereof;
- a neutralizing agent;
- liquid carrier;
- and
- a filler, wherein the filler and polymeric binder are present at a weight ratio ranging from about 2:1 to about 6:1;
- wherein the coating composition is formaldehyde-free and has a pH of at least 8;
- and
- drying the coating composition applied to the substrate such that the liquid carrier is evaporated to form the sag-resistant building panel.
A method of manufacture of a sag-resistant building panel comprising
- applying an aqueous coating composition to a major surface of a fibrous substrate, the coating composition comprising:
- a polymeric binder comprising polyacrylic acid;
- a hydroxyl-functional crosslinker;
- a neutralizing agent;
- filler;
- a wetting agent;
- and
- wherein a weight ratio of filler to polymeric binder ranges from about 2:1:
- to about 6:1, and the coating composition has a metal ion concentration of less than 1000 ppm;
- and
- drying the coating composition applied to the fibrous substrate such that the liquid carrier is evaporated to form the sag-resistant building panel.
A method of manufacture of a sag-resistant building panel comprising
- applying a coating composition to a major surface of a fibrous substrate, the coating composition comprising a blend of:
- a polymeric binder comprising polyacrylic acid that is at least partially neutralized with a volatile base;
- a crosslinker;
- liquid carrier;
- filler;
- a wetting agent;
- and
- wherein the coating composition is formaldehyde-free and is free of any single or multi-valence metal ions selected from sodium, potassium, and calcium, and the coating composition has a pH of at least about 6;
- wherein the filler and polymeric binder are present at a weight ratio ranging from about 2:1 to about 6:1;
- and
- drying the coating composition applied to the fibrous substrate such that the liquid carrier is evaporated to form the sag-resistant building panel.
Dependencies are inferred from the claim text.