Curable composition
A curable composition, useful as a thermosetting binder, having a polycarboxy polymer or co-polymer, an emulsion polymer, and a multifunctional polyol.
1. A curable aqueous composition comprising
(a) at least one polycarboxy (co)polymer comprising at least two carboxylic acid groups, anhydride groups, or salts thereof and chosen from polyesters, oligomers, co-oligomers, solution polymers in aqueous media, and solution copolymers in aqueous media;
(b) polymer particles of at least one emulsion (co)polymer having a glass transition temperature, Tg, of less than 80° C., as determined by the Fox equation;
and (c) at least one polyol selected from the group consisting of “diglycerol, triglycerol, ditrimethylolpropane, 1 to 15-propoxylated pentaerythritol, 1 to 15-ethoxylated pentaerythritol, 1 to 15-propoxylated ditrimethylolpropane, 1 to 15-ethoxylated ditrimethylolpropane, 1-15-ethoxylated dipentaerythritol, 1-15-propoxylated dipentaerythritol, and mixtures thereof”.
2. The curable aqueous composition of claim 1 wherein the at least one emulsion (co)polymer (b) has a glass transition temperature, Tg, of less than 50° C., as determined by the Fox equation.
3. The curable aqueous composition of claim 1 wherein the polycarboxy (co)polymer (a) is an addition polymer or copolymer comprising at least one (co)polymerized ethylenically unsaturated carboxylic acid-containing monomer.
4. The curable aqueous composition of claim 1 further comprising one or more polyols selected from the group consisting of glycerol, ethyleneglycol, diethyleneglycol, triethyleneglycol, hexanediol, trimethylolpropane, sorbitol, sucrose; and glucose.
5. The curable aqueous composition of claim 1 wherein the emulsion (co)polymer is present in an amount of from 1% to 50%, by weight, based on the sum of the weight of the polycarboxy (co)polymer (a) and the weight of the polyol (c), all weights being taken on a solids basis.
6. The curable aqueous composition of claim 1 further comprising a phosphorous-containing accelerator.
7. A method for treating a substrate with the curable aqueous composition as claimed in claim 1 comprising contacting the substrate with the curable aqueous composition or, alternatively, applying the curable aqueous composition to the substrate; and,
heating the curable aqueous composition at a temperature of from 100° C. to 400° C.