Process for the production of uretdione polyisocyanates with improved monomer stability

• US 6,444,778 B1
• Filed: 07/16/2001
• Issued: 09/03/2002
• Est. Priority Date: 07/19/2000
• Status: Expired due to Term

• Current Assignee: Bayer AG
• Original Assignee: Bayer AG
• Inventors: Mager, Dieter, Laas, Hans-Josef, Halpaap, Reinhard
• Primary Examiner(s): Lambkin, Deborah C.
• Application Number:
  US09/906,194
• Publication Number:
  US 20020028930A1
• Time in Patent Office: 414 Days
• Field of Search: 528/61, 528/60
• US Class Current: 528/61
• CPC Class Codes: C08G 18/027 the polymeric products containing urethodione groups
• CPC Class Codes: C08G 18/089 Reaction retarding agents
• CPC Class Codes: C08G 18/798 containing urethdione groups

Abstract

The invention relates to a process for the production of uretdione polyisocyanates with improved storage stability and their use as a starting component for polyurethane plastics, in particular as a crosslinker component for the production of two-component polyurethane coating compositions.

Claims

1. A process for the production of polyisocyanates containing uretdione groups comprising the steps of

oligomerizing a portion of the isocyanate groups of a starting diisocyanate with aliphatically and/or cycloaliphatically bonded isocyanate groups in the presence of a tertiary phosphine,

terminating the oligomerization reaction at a desired oligomerization level and removal of the non-converted excess starting diisocyanate by extraction or thin-layer distillation,

characterized in that the oligomerization reaction is carried out in the presence of ureas of formula (I) and/or amides of formula (II),

wherein

R¹, R² and R³ represent independently of one another a hydrogen atom, a saturated or unsaturated aliphatic or cycloaliphatic, an optionally substituted aromatic or araliphatic group, which may contain up to 18 carbon atoms and optionally up to 3 hetero atoms selected from oxygen, sulfur, nitrogen,

R⁴ has the meaning given for R¹ to R³ or represents the group

wherein X represents a divalent, optionally branched, aliphatic or cycloaliphatic group with up to 12 carbon atoms, and R¹ has the meaning given above,

or

R¹, R² and R³ in formula (I), and

R¹ and R⁴ in formula (II) in combination with each other together with the nitrogen atoms of the urea or amide group, and optionally a further nitrogen atom or an oxygen atom can also form heterocyclic rings with 3 to 6 carbon atoms.

2. The process of claim 1, wherein the diisocyanates comprise 1,6-diisocyanatohexane and/or 1 -isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane.

3. The process of claim 1, wherein the tertiary phosphine comprises trialkyl phosphine.

4. The process of claim 1, wherein the tertiary phosphines are tributyl phosphine and/or trioctyl phosphine.

5. The process of claim 1, wherein the ureas are described by formula (I), wherein

R¹, R² and R³ represent independently of one another a hydrogen atom or a saturated or unsaturated aliphatic or cycloaliphatic group with up to 12 carbon atoms,

and

R¹, R² and R³ in combination with each other together with at least one nitrogen atom of the urea group and optionally a further nitrogen atom or an oxygen atom, can also form heterocyclic rings with 3 to 6 carbon atoms.

6. The process of claim 1, wherein the ureas are described by formula (I), wherein

R¹ represents a hydrogen atom, and

R² and R³ each represent a hydrogen atom or a saturated aliphatic or cycloaliphatic group with up to 8 carbon atoms.

7. The process of claim 1, wherein the amides are described by formula (II), wherein

R¹ represents a hydrogen atom or a saturated aliphatic or cycloaliphatic or an optionally substituted aromatic group with up to 12 carbon atoms,

R⁴ has the meaning given for R¹ or represents the group

wherein X represents a divalent, optionally branched aliphatic or cycloaliphatic group with up to 6 carbon atoms, and R¹ has the given meaning,

and

R¹ and R⁴ together with the nitrogen atom of the amide group and optionally a further nitrogen atom or an oxygen atom can also form heterocyclic rings with 3 to 6 carbon atoms.

8. The process of claim 1, wherein the amides are described by formula (II), wherein

R¹ represents a hydrogen atom or a saturated aliphatic group with 1 to 4 carbon atoms, and

R⁴ represents an optionally substituted aromatic group with 1 to 12 carbon atoms.

9. The process of claim 1, wherein the amides are described by formula (II), wherein

R¹ and R⁴ together with the nitrogen atom of the amide group and optionally a further nitrogen atom or an oxygen atom form a heterocyclic ring with 3 to 6 carbon atoms,

or wherein

R¹ represents a hydrogen atom, and

R⁴ represents the group

wherein X represents a divalent aliphatic group with up to 4 carbon atoms.

10. The process of claim 1, wherein the urea is N,N-dimethyl urea and/or N,N-diethyl urea.

11. The process of claim 1, wherein the stabilizer is present in a quantity of 0.02 to 2 wt.-% based on the weight of the starting diisocyanate.

12. The process of claim 1, wherein the stabilizer is present in a quantity of 0.05 to 1 wt.-% based on the weight of the starting diisocyanate.

13. A method of producing polyurethane plastics comprising the step of reacting the polyisocyanates containing uretdione groups according to claim 1 as starting components.

14. A binder composition comprising a crosslinker composition comprising the polyisocyanates containing uretdione groups according to claim 1, optionally in the form in which they are blocked with blocking agents.