Malonic acid ester/triazole mixed blocked HDI trimer/formaldehyde stabilization
AssigneeBayer Aktiengesellschaft
InventorsEberhard König, Hans-Ulrich Meier-Westhues, Thomas Klimmasch
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Abstract
The present invention relates to blocked polyisocyanate crosslinking agents, to the production thereof and to the use thereof in single-component stoving lacquers, particularly OEM clear lacquers (original equipment material, initial lacquer coating).
Claims8
An aliphatic and/or cycloaliphatic polyisocyanate having blocked isocyanate groups wherein
- A) 5-95 equivalent % of the isocyanate groups are blocked with an acidic CH ester,
- B) 5-95 equivalent % of the isocyanate groups are blocked with 1,2,4-triazole,
- C) 0-10 equivalent % of the isocyanate groups are blocked with a blocking agent different from A) and B),
- D) the percentages of A), B) and C add up to 100%, and
- E) said aliphatic and/or cycloaliphatic polyisocyanate having blocked isocyanate groups contains 0.05-1.0 mole of formaldehyde in chemically incorporated form, based on 1 equivalent of blocked NCO groups.
A process of producing a non-crystallizing aliphatic and/or cycloaliphatic polyisocyanate having blocked isocyanate groups which comprises reacting an aliphatic and/or cycloaliphatic polyisocyanate having blocked isocyanate groups wherein
- A) 5-95 equivalent % of the isocyanate groups are blocked with an acidic CH ester,
- B) 5-95 equivalent % of the isocyanate groups are blocked with 1,2,4-triazole,
- C) 0-10 equivalent % of the isocyanate groups are blocked with a blocking agent different from A) and B), and
- D) the percentages of A), B) and C add up to 100% with 0.05-1.0 mole of formaldehyde, based on 1 equivalent of blocked isocyanate groups.
An aliphatic and/or cycloaliphatic polyisocyanate having blocked isocyanate groups wherein
- A) 5-95 equivalent % of the isocyanate groups are blocked with an acidic CH ester,
- B) 5-95 equivalent % of the isocyanate groups are blocked with 1,2,4-triazole,
- C) 0-10 equivalent % of the isocyanate groups are blocked with a blocking agent different from A) and B),
- D) the percentages of A), B) and C add up to 100%, and
- E) said aliphatic and/or cycloaliphatic polyisocyanate having blocked isocyanate groups contains 0.8-5.0% by weight of formaldehyde in chemically incorporated form, based on the weight of said aliphatic and/or cycloaliphatic polyisocyanate having blocked isocyanate groups.
A process of producing a non-crystallizing aliphatic and/or cycloaliphatic polyisocyanate having blocked isocyanate groups which comprises reacting an aliphatic and/or cycloaliphatic polyisocyanate having blocked isocyanate groups wherein
- A) 5-95 equivalent % of the isocyanate groups are blocked with an acidic CH ester,
- B) 5-95 equivalent % of the isocyanate groups are blocked with 1,2,4-triazole,
- C) 0-10 equivalent % of the isocyanate groups are blocked with a blocking agent different from A) and B), and
- D) the percentages of A), B) and C add up to 100% with 0.8-5.0% by weight of formaldehyde, based on the weight of said aliphatic and/or cycloaliphatic polyisocyanate having blocked isocyanate groups.
Dependencies are inferred from the claim text.