Process for preparing oligomeric aliphatic diols, polycarbonatediols based thereon and prepolymers thereof

• US 20040152861A1
• Filed: 01/22/2004
• Published: 08/05/2004
• Est. Priority Date: 01/31/2003
• Status: Active Grant

• Current Assignee: Bayer AG
• Original Assignee: Bayer AG
• Inventors: Ruprecht, Hans-Dieter, Schmidt, Manfred, Nefzger, Hartmut, Bauer, Erika, Barnes, James-Michael
• Granted Patent: US 6,977,290 B2
• Time in Patent Office: Days
• US Class Current: 528/76
• CPC Class Codes: C07C 41/09 by dehydration of compounds containing hydroxy groups
• CPC Class Codes: C07C 43/135 having more than one ether bond
• 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 18/44 Polycarbonates
• CPC Class Codes: C08G 64/0208 saturated
• CPC Class Codes: C08G 64/305 and alcohols
• CPC Class Codes: C08G 65/34 from hydroxy compounds or their metallic derivatives C08G65/26 takes precedence

Abstract

The present invention relates to a method for preparing oligomeric aliphatic diols, polycarbonatediols based thereon and NCO-terminated prepolymers obtainable therefrom. The inventive compounds may find use in the preparation of polyurethanes.

Claims

1. In a process for preparing oligomeric aliphatic diols, the improvement comprising including a phase separation step in the work up of the reaction mixture to give an organic and an aqueous phase.

3. A process for preparing polycarbonatediols comprising reacting an oligomeric aliphatic diol prepared according to claim 1 with a sub-stoichiometric amount of a carbonate donor in the presence of a catalyst.

4. The process according to claim 3, wherein the catalyst comprises a basic magnesium salt.

5. The process according to claim 3 wherein the carbonate donor comprises diphenyl carbonate.

6. A process for preparing NCO-terminated prepolymers comprising reacting sub-stoichiometric amounts of the polycarbonatediol made according to claim 4 with a polyisocyanate.

7. The process according to claim 6, wherein the polyisocyanate comprises diphenylmethane diisocyanate.

8. In a process of preparing polyurethane, the improvement comprising incorporating at least one oligomeric aliphatic diol made according to claim 1.

10. In a process of preparing polyurethane, the improvement comprising incorporating at least one NCO-terminated prepolymer made according to claim 6.

2. A process for preparing oligomeric aliphatic diols comprising:

oligomerizing an aliphatic diol in the presence of an acid catalyst and an entraining agent, wherein the water formed is distilled off azeotropically,

adding an aqueous base to the reaction mixture after reaching the desired degree of oligomerization and hydrolyzing any esters formed during oligomerization,

adjusting the pH of the reaction mixture of 4.0 to 8.0 by adding non-oxidizing inorganic acids or the salts thereof, and,

isolating, dewatering and filtering the organic phase after phase separation of the reaction mixture.

9. In a process of preparing polyurethane, the improvement comprising incorporating at least one oligomeric aliphatic diol made according to claim 2.