Aqueous polyurethane-polyurea dispersions
AssigneeStahl International B.V.
InventorJuergen Muenter
Life of this patent
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Abstract
The present invention relates to aqueous polyurethane-polyurea dispersions which stabilize a foam—produced by mechanical expansion—without addition of further foam-stabilizing components in such a way that aqueous foams are obtainable which are stable both during temporary storage and during processing, so that they can be applied in the form of foam also by customary application methods and substantially retain the foam structure even after drying.
Claims19
Process for the preparation of a foam-stabilising aqueous polyurethane-polyurea dispersion, comprising the steps of
- A) first a polyurethane prepolymer containing NCO groups—having an NCO functionality of less than two—is produced by reacting
- A1) polyisocyanates with
- A2) polymeric polyols, polyamines, or a mixture thereof, wherein the polymeric polyols, polyamines, or mixture thereof have number average molecular weights of 400 to 8000 g/mol,
- A3) isocyanate-reactive, non-ionically hydrophilising compounds which are polyoxyalkylene ethers which contain at least one hydroxyl or amino group,
- A4) isocyanate-reactive compounds containing C7-24-alkyl or C7-24-alkenyl groups, and having 2, 3, or 4 isocyanate-reactive groups, and
- A6) isocyanate-reactive, ionically or potentially ionically hydrophilising compounds,
- and
- B) the still free NCO groups of the prepolymer are reacted with a compound A8), wherein the compound A8) is selected from the group consisting of isocyanate-reactive amino alcohols, monoamines, polyamines, hydrazine, hydrazides and mixtures thereof, in an amount such that a theoretical ratio of the isocyanate-reactive NH groups of the compound A8) to the NCO groups of the prepolymer from 0.8 to 1.2 is achieved,
- wherein no foam-stabilizing additives are included in said dispersion.
An aqueous foam-stabilising polyurethane-polyurea dispersion made by a process comprising the steps of
- A) first a polyurethane prepolymer containing NCO groups—having an NCO functionality of less than two—is produced by reacting
- A1) polyisocyanates with
- A2) polymeric polyols, polyamines, or a mixture thereof, wherein the polymeric polyols, polyamines, or mixture thereof have number average molecular weights of 400 to 8000 g/mol,
- A3) isocyanate-reactive, non-ionically hydrophilising compounds which are polyoxyalkylene ethers which contain at least one hydroxyl or amino group,
- A4) isocyanate-reactive compounds containing C7-24-alkyl or C7-24-alkenyl groups and having 2, 3, or 4 isocyanate-reactive groups, and
- A6) isocyanate-reactive, ionically or potentially ionically hydrophilising compounds
- and
- B) the still free NCO groups of the prepolymer are reacted with a compound A8), wherein the compound A8) is selected from the group consisting of isocyanate-reactive amino alcohols, monoamines, polyamines, hydrazine, hydrazides and mixtures thereof, in an amount such that a theoretical ratio of the isocyanate-reactive NH groups of the compound A8) to the NCO groups of the prepolymer from 0.8 to 1.2 is achieved,
- wherein no foam-stabilizing additives are included in said dispersion.
Dependencies are inferred from the claim text.