Cholesteric copolyisocyanates

• US 5,847,068 A
• Filed: 04/03/1997
• Issued: 12/08/1998
• Est. Priority Date: 04/03/1997
• Status: Expired due to Fees

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Novak, Bruce M., Keller, Harald, Zentel, Rudolf, Maxein, Georg
• Primary Examiner(s): GORR, RACHEL F
• Application Number:
  US08/834,745
• Time in Patent Office: 614 Days
• Field of Search: 528/44, 528/56, 528/69, 528/73, 528/75, 525/452
• US Class Current: 528/69
• CPC Class Codes: C08G 18/02 of isocyanates or isothiocyanates only
• CPC Class Codes: C09K 19/00 Liquid crystal materials

Abstract

Cholesteric copolyisocyanates with repeating units of the formulae: ##STR1## and, where appropriate, of the formula ##STR2## where R¹ is a chiral aliphatic or aromatic radical,

R² is a crosslinkable radical, and

R³ is an achiral radical,

and polymers obtainable by crosslinking the copolyisocyanates according to the invention with a polymerizable solvent, and pigments comprising the polymers according to the invention, are described.

Claims

1. A cholesteric copolyisocyanate with repeating units of the formulae:

##STR6## and, where appropriate, of the formula ##STR7## where R¹ is a chiral aliphatic or aromatic radical,

R² is a crosslinkable radical, and

R³ is an achiral radical.

2. The copolyisocyanate as claimed in claim 1, where R¹ is selected from chiral branched or unbranched alkyl, alkoxyalkyl, alkylthioalkyl, cycloalkyl, alkylphenyl or C₃ -C₉ -epoxyalkyl radicals or radicals from esters of C₁ -C₆ -fatty acids with C₁ -C₆ -alkanols or C₃ -C₉ -dialkyl ketones, where R¹ can have 1, 2 or 3 substituents which are identical or different and are selected from alkoxy groups, di-C₁ -C₄ -alkylamino groups, CN, halogen atoms or C₁ -C₄ -alkylthio groups.

3. The copolyisocyanate as claimed in claim 1, where the main chain of the radical R¹ has a length of from 3 to 12 carbons.

4. The copolyisocyanate as claimed in claim 1, where R¹ is selected from the group consisting of ##STR8##

5. The copolyisocyanate as claimed in claim 1, where R¹ is 2,6-dimethylheptyl.

6. The copolyisocyanate as claimed in claim 1, where R² is selected from the group consisting of C₃ -C₁₁ -alkenyl radicals, C₄ -C₁₁ -vinyl ether residues, ethylenically unsaturated C₃ -C₁₁ -carboxylic acid residues and esters of ethylenically unsaturated C₃ -C₆ -monocarboxylic acids with C₂ -C₆ -alkanols, wherein bonding to the nitrogen atom takes place via the alkanol residue of the ester.

7. The copolyisocyanate as claimed in claim 1, where R² is selected from the group consisting of residues of methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, ethyl acrylate and ethyl methacrylate.

8. The copolyisocyanate as claimed in claim 1, where R³ is selected from the group consisting of branched or unbranched alkyl, alkoxyalkyl, alkylthioalkyl, C₃ -C₉ -epoxyalkyl, cycloalkyl, alkylaryl radicals and radicals from esters of C₁ -C₆ -fatty acids with C₁ -C₆ -alkanols and C₃ -C₉ -dialkyl ketones, where R³ optionally has 1, 2 or 3 substituents which are identical or different, and are selected from the group consisting of alkoxy groups, dialkylamino groups, CN, halogen atoms and C₁ -C₄ -alkylthio groups.

9. The copolyisocyanate as claimed in claim 1, where the main chain of the radical R³ has a length of from 4 to 12 carbons.

10. The copolyisocyanate as claimed in claim 1, where R³ is n-hexyl, n-heptyl or n-octyl.

11. The copolyisocyanate as claimed in claim 1, where components a), b) and c) are present in the a:

b;

c ratio of molar amounts of about 1-20;

1-20;

50-98.

12. A cholesteric polymer obtained by

i) dissolving copolyisocyanates as claimed in any of the preceding claims in a polymerizable solvent, and

ii) crosslinking the copolyisocyanates and solvent together.

13. The polymer as claimed in claim 12, wherein the polymerizable solvent is selected from esters of α

,β

-unsaturated C₃ -C₆ -mono- or dicarboxylic acids with C₁ -C₁₂ -alkanols, vinyl ethers, vinyl esters, epoxides, N-vinylpyrrolidone, N-vinylcaprolactam, vinylaromatic compounds, and compounds containing two or more crosslinkable groups.

14. The polymer as claimed in claim 12, wherein styrene is employed as polymerizable solvent.

15. A pigment, comprising polymers as claimed in claim 12.

16. The copolyisocyanate as claimed in claim 11, where components a), b) and c) are present in the a:

b;

c;

ratio of molar amounts of about 5-15;

5-15;

65-90.

17. The copolyisocyanate as claimed in claim 11, where components a), b) and c) are present in the a:

b;

c;

ratio of molar amounts of about 15;

10;

75.

18. A coating composition, comprising copolyisocyanates as claimed in claim 1 or pigments as claimed in claim 15.

19. A process for preparing copolyisocyanates as claimed in claim 1, which comprises polymerizing the monomers underlying components a), b) and optionally, c) in the presence of a catalyst of the formula CpTiCl₂ OCH₂ CF₃, CpTiCl₂ CH₃ or CpTiCl₂ N(CH₃)₂, where Cp is η

⁵ -cyclopentadienyl.

20. The copolyisocyanate as claimed in claim 3, where the main chain of the radical R¹ has a length of from 6 to 10 carbons.

21. The copolyisocyanate as claimed in claim 20, where the main chain of the radical R¹ has a length of from 6 to 8 carbons.

22. The copolyisocyanate as claimed in claim 9, where the main chain of the radical R³ has a length of from 6 to 8 carbons.

23. The copolyisocyanate as claimed in claim 22, where the main chain of the radical R³ has a length of from 6 to 8 carbons.