Poly (vinyl alcohol)—based formaldehyde-free curable aqueous composition
AssigneeDynea Oy
InventorsElena Pisanova, Robert Schmidt, Alexander Tseitlin
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Abstract
A formaldehyde-free curable aqueous composition containing polyvinyl alcohol, a multi-functional crosslinking agent, and, optionally, a catalyst. The composition may be used as a binder for non-woven products such as fiberglass insulation. The non-woven products are formed by contacting the formaldehyde-free curable aqueous composition with fibrous components and the mixture is cured to form a rigid thermoset polymer providing excellent strength and water resistance of the cured nonwoven product.
Claims28
A curable aqueous composition prepared by a process comprising combining the following components:
- (a) a hydroxy-containing polymer which is a combination of polyvinyl alcohol and at least one member selected from the group consisting of starch, modified starch and a sugar;
- (b) a multi-functional crosslinking agent which includes citric acid as a first nonpolymeric polyacid and optionally at least one selected from the group consisting of a second nonpolymeric polyacid, salts thereof, an anhydride, and a nonpolymeric polyaldehyde, and optionally
- (c) a catalyst;
- wherein the weight ratio of (a):(b) is from 95:5 to about 35:65,
- wherein the pH of the curable composition is increased in a positive direction to at least 1.25 upon addition of a nitrogenous base,
- wherein said polyvinyl alcohol has a viscosity up to 10 centipoise when in a 4% aqueous solution at 20° C.
A method of forming a curable aqueous composition comprising the following steps:
- a step of combining (a) a hydroxy-containing polymer with (b) a multi-functional crosslinking agent which includes citric acid as a first nonpolymeric polyacid and optionally at least one selected from the group consisting of a second nonpolymeric polyacid, salts thereof, an anhydride, and a nonpolymeric polyaldehyde, and optionally
- (c) a catalyst to form a curable aqueous composition;
- and
- a step of adding sufficient nitrogenous base to raise the pH in a positive direction to at least 1.25;
- wherein the weight ratio of (a):(b) is from 95:5 to about 35:65;
- and
- wherein said hydroxy-containing polymer is a combination of polyvinyl alcohol and at least one member selected from the group consisting of starch, modified starch and a sugar,
- wherein said polyvinyl alcohol has a viscosity up to 10 centipoise when in a 4% aqueous solution at 20° C.
A method for forming a nonwoven material comprising the following steps:
- combining (a) a hydroxy-containing polymer with (b) a multi-functional crosslinking agent which includes citric acid as a first nonpolymeric polyacid and optionally at least one selected from the group consisting of a second nonpolymeric polyacid, salts thereof, an anhydride, and a nonpolymeric polyaldehyde, and optionally (c) a catalyst to form a curable aqueous composition;
- and
- a step of adding sufficient nitrogenous base to raise the pH in a positive direction to at least 1.25;
- and
- combining the curable aqueous composition with nonwoven fiber, and
- heating the curable aqueous composition and nonwoven fiber at 130° C. to 250° C. for sufficient time to effect cure,
- wherein the weight ratio of (a):(b) is from 95:5 to about 35:65;
- and
- wherein said hydroxy-containing polymer is a combination of polyvinyl alcohol and at least one member selected from the group consisting of starch, modified starch and a sugar,
- wherein said polyvinyl alcohol has a viscosity up to 10 centipoise when in a 4% aqueous solution at 20° C.
A curable aqueous composition prepared by a process comprising combining the following components:
- (a) a hydroxy-containing polymer which is a combination of polyvinyl alcohol and at least one member selected from the group consisting of starch, modified starch and a sugar;
- (b) a multi-functional crosslinking agent which includes citric acid as a first nonpolymeric polyacid and optionally at least one selected from the group consisting of a second nonpolymeric polyacid, salts thereof, an anhydride, and a nonpolymeric polyaldehyde,
- (c) a base, and optionally
- (d) a catalyst;
- wherein the weight ratio of (a):(b) is from 95:5 to about 35:65,
- wherein the pH of the curable composition is increased in a positive direction to at least 1.25 upon addition of a nitrogenous base,
- wherein said polyvinyl alcohol has a viscosity up to 10 centipoise when in a 4% aqueous solution at 20° C.
Dependencies are inferred from the claim text.