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US 4,286,080 AGranted
Extrusion process for the preparation of polyurethane ureas
AssigneeBayer Aktiengesellschaft
InventorsBernd Quiring, Wolfgang Wenzel, Georg Niederdellmann, Hans Wagner, Wilhelm Goyert
Life of this patent
Estimating the term…
Abstract
The present invention relates to a process for the preparation of polyurethane ureas from relatively high molecular weight polyols, diisocyanates, water as chain lengthening agent and optionally short chain glycols in a multishaft extruder equipped with kneading elements.
Claims10
A process for the continuous preparation of polyurethane ureas by reacting, either all at one time or stepwise, a reaction mixture comprising:
- (A) one or more polyisocyanates;
- (B) one or more compounds having an average of at least 1.8 Zerewitinoff-active hydrogen atoms and a molecular weight of from 400 to 10,000;
- (C) water in a quantity of from 0.07 to 40% by weight, based on the sum of Zerewitinoff-active compounds (B), (C) and (D);
- optionally with
- (D) other compounds having one or more Zerewitinoff-active hydrogen atoms and having a molecular weight of from 32 to 400;
- and optionally
- (E) monoisocyanates;
- further characterized in that the equivalent ratio of component (B) to the sum of components (C) and (D) is from 5:1 to 1:30, the molar proportion of component (C) amounts to at least 5% of the sum of (C) and (D) and the equivalent ratio of isocyanate groups to all the Zerewitinoff-active hydrogen atoms, including water, is below 1.1:1, further characterized in that said reaction is carried out in hot screw extruders, comprising:
- (a) multishaft extruders with self-cleaning screws and kneading elements;
- (b) introducing components (A), (B) and optionally (D) and (E) into said hot screw extruder;
- (c) introducing component (C) into said screw-extruder, where the temperature in those extruders is between 120.degree. and 280.degree. C., thereby transferring component (C) into the gaseous phase;
- (d) adjusting pressure and temperature in the reaction zone of the extruders as to keep component C into the gaseous phase;
- (e) adjusting the temperature in the extrusion zone so as to subject the extrudate to a pressure of at least 10 bar.
10 more elements
A process for the continuous preparation of polyurethane ureas by reacting, either all at one time or stepwise, a reaction mixture comprising:
- (A') an isocyanate group-containing prepolymer obtained by prereacting (1) one or more polyisocyanates and (2) one or more compounds having an average of at least 1.8 Zerewitinoff-active hydrogen atoms and a molecular weight in the range of 400 to 10,000;
- (B) water in a quantity of from 0.07 to 40% by weight, based on the sum of Zerewitinoff-active compounds (A',2),(B) and (C);
- optionally with
- (C) other compounds having one or more Zerewitinoff-active hydrogen atoms and having a molecular weight of from 32 to 400;
- and optionally
- (D) monoisocyanates;
- further characterized in that the equivalent ratio of component (A') (2) to the sum of components (B) and (C) is from 5:1 to 1:30, the molar proportion of component (B) amounts to at least 5% of the sum of (B) and (C) and the equivalent ratio of isocyanate groups to all the Zerewitinoff-active hydrogen atoms, including water, is below 1.1:1, further characterized in that said reaction is carried out in hot screw extruders, comprising
- (a) multishaft extruders with self-cleaning screws and kneading elements;
- (b) introducing components (A'), (C) and optionally (D) into said hot screw extruders
- (c) introducing component (B) into said screw extruders, where the temperature in those extruders is between 120.degree. and 280.degree. C., thereby transferring component (B) into the gaseous phase;
- (d) adjusting pressure and temperature in the reaction zone as to keep component (B) in the gaseous phase;
- (e) adjusting the temperature in the extrusion zone so as to subject the extrudate to a pressure of at least 10 bar.
9 more elements
Dependencies are inferred from the claim text.