Method for producing polyurethane prepolymer having a low content of monomers

• US 20050020706A1
• Filed: 06/18/2004
• Published: 01/27/2005
• Est. Priority Date: 12/18/2001
• Status: Abandoned Application

• Current Assignee: Henkel KGaA (Henkel AG & Co KGaA)
• Original Assignee: Henkel KGaA (Henkel AG & Co KGaA)
• Inventors: Bolte, Gerd, Hupfer-Bolte, Heike Ulrike, Kollbach, Guido, Hassel, Nina
• Application Number:
  US10/871,343
• Publication Number:
  US 20050020706A1
• Time in Patent Office: Days
• US Class Current: 521/159
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/42 Polycondensates having carboxylic or carbonic ester groups in the main chain
• CPC Class Codes: C08G 18/48 Polyethers
• CPC Class Codes: C08G 18/792 formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates
• CPC Class Codes: C08G 2101/00 Manufacture of cellular products
• CPC Class Codes: C08G 2190/00 Compositions for sealing or packing joints
• CPC Class Codes: C09J 175/04 Polyurethanes

Abstract

This invention describes a process for the production of isocyanate-terminated polyurethane prepolymers by reacting polyisocyanates in stages with polyols and to their use.

Claims

1. A process for the production of isocyanate-terminated polyurethane prepolymers, in which polyisocyanates are reacted with polyols,

(I) the polyisocyanate used in a first synthesis stage being

a) at least one nonsymmetrical diisocyanate,

b) the polyol being at least one polyol with an average molecular weight (M_n) of 60 to 3000 g/mol,

c) the ratio of isocyanate groups to hydroxyl groups being in the range from 1.5:

1 to 3;

1,

d) an organometallic compound or ε

-caprolactam being added as catalyst and, after the reaction,

(II) in a second synthesis stage,

a) at least one other polyol being added so that the overall ratio of isocyanate groups to hydroxyl groups is in the range from 1.1;

1 to 2;

1.

2. A process as claimed in claim 1, characterized in that at least one nonsymmetrical diisocyanate from the group comprising toluene diisocyanate (TDI) either in the form of the pure isomer or as a mixture of several isomers;

1-isocyanatomethyl-3-isocyanato-1,5,5-trimethyl diisocyanate (isophorone diisocyanate, IPDI);

2,4-diphenylmethane diisocyanate is used in the first synthesis stage.

3. A process as claimed in claim 1, characterized in that at least one polyol with an average molecular weight (M_n) of 200 to 1200 g/mol is used in the first synthesis stage.

4. A process as claimed in claim 1, characterized in that at least one polyether polyol with a molecular weight (M_n) of 100 to 3000 g/mol and/or at least one polyester polyol with a molecular weight (M_n) of 100 to 3000 g/mol is/are used in the first synthesis stage.

5. A process as claimed in claim 1, characterized in that polyether polyols with a molecular weight of 100 to 10000 g/mol and/or polyester polyols with a molecular weight of 200 to 10000 g/mol are used in the second synthesis stage.

6. A process as claimed in claim 1, characterized in that the monomer concentration in the polyurethane prepolymer produced is below 0.3% by weight.

7. A process as claimed in claim 1, characterized in that the polyurethane prepolymer has a Brookfield viscosity at 100°

C. (as measured to ISO

     2555) in the range from 100 mPas to 15000 mPas.

8. The use of the isocyanate-terminated polyurethane prepolymer produced by the process claimed in any of claims 1 to 7 for the production of reactive one- or two-component adhesives/sealants.

9. The use claimed in claim 8 for the production of reactive hotmelt adhesives and solventless or solvent-containing laminating adhesives.

10. The use of the isocyanate-terminated polyurethane prepolymer produced by the process claimed in any of claims 1 to 7 for the production of assembly foams, potting compounds and rigid, flexible and integral foams.