UV stabilized compositions with improved solubility
First Claim
1. A UV-stabilized composition which comprises (a) an aprotic polar solvent, (b) at least one electrochromic compound, and (c) a compound of the formula I ##STR4## wherein R1 is H, a straight or branched alkyl group containing 1 to 18 carbons, or R3 --COO--R4, where R3 is a single bond, or is a straight or branched alkylene group containing 1-6 carbons and R4 is a straight or branched alkyl group containing 1-18 carbons, and if R1 is H or a straight or branched alkyl group containing 1 to 18 carbons, then R2 is R3 --COO--R4, and if R1 is R3 --COO--R4, then R2 is H, a straight or branched alkyl group containing 1 to 18 carbons, or R5 --COO--R6, where R5 is a single bond, or is a straight or branched alkylene group containing 1 to 6 carbons, and R6 is a straight or branched alkyl group containing 1-18 carbons.
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Abstract
The present invention concerns compositions, which comprise an aprotic polar solvent, at least one electrochromic compound, and a compound of the formula I ##STR1## wherein R1 is, for example, tert-butyl, and R2 is, for example, --CH2 --CH2 --COO--R7 --, where R7 is n-butyl or n-pentyl. Among embodiments of the invention are compositions used as media of variable transmittance in electrochromic devices, especially single-compartment, self-erasing, solution-phase electrochromic devices. The compounds of Formula I have increased solubility in aprotic polar solvents used in electrochromic devices and are effective in stabilizing compositions, which comprise at least one electrochromic compound and are useful as media of variable transmittance in electrochromic devices, against degradation due to exposure to UV-radiation. The compounds of Formula I further significantly assist in controlling the gel formation time of cross-linked polymer matrices, which comprise at least one electrochromic compound and are useful as media of variable transmittance in electrochromic devices.
27 Citations
30 Claims
- 1. A UV-stabilized composition which comprises (a) an aprotic polar solvent, (b) at least one electrochromic compound, and (c) a compound of the formula I ##STR4## wherein R1 is H, a straight or branched alkyl group containing 1 to 18 carbons, or R3 --COO--R4, where R3 is a single bond, or is a straight or branched alkylene group containing 1-6 carbons and R4 is a straight or branched alkyl group containing 1-18 carbons, and if R1 is H or a straight or branched alkyl group containing 1 to 18 carbons, then R2 is R3 --COO--R4, and if R1 is R3 --COO--R4, then R2 is H, a straight or branched alkyl group containing 1 to 18 carbons, or R5 --COO--R6, where R5 is a single bond, or is a straight or branched alkylene group containing 1 to 6 carbons, and R6 is a straight or branched alkyl group containing 1-18 carbons.
- 17. An electrochromic device comprising a UV-stabilized composition which comprises (a) an aprotic polar solvent, (b) at least one electrochromic compound, and (c) a compound of the formula I ##STR5## wherein R1 is H, a straight or branched alkyl group containing 1 to 18 carbons, or R3 --COO--R4, where R3 is a single bond, or is a straight or branched alkylene group containing 1-6 carbons and R4 is a straight or branched alkyl group containing 1-18 carbons, and if R1 is H or a straight or branched alkyl group containing 1 to 18 carbons, then R2 is R5 --COO--R6, where R5 is a single bond, or is a straight or branched alkylene group containing 1 to 6 carbons, and R6 is a straight or branched alkyl group containing 1-18 carbons, and if R1 is R3 --COO--R4, then R2 is H, a straight or branched alkyl group containing 1 to 18 carbons, or R5 --COO--R6.
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23. An electrochromic medium of reversibly variable transmittance to light which comprises:
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(a) a solvent (b) a cross-linked polymer matrix resulting from crosslinking polymer chains that are formed by polymerizing at least one monomer; (c) at least one electrochromic compound in solution in said solvent and interspersed in said polymer matrix; and (d) a compound of the formula I ##STR6## wherein R1 is H, a straight or branched alkyl group containing 1 to 18 carbons, or R3 --COO--R4, where R3 is a single bond, or is a straight or branched alkylene group containing 1-6 carbons and R4 is a straight or branched alkyl group containing 1-18 carbons, and if R1 is H or a straight or branched alkyl group containing 1 to 18 carbons, then R2 is R5 --COO--R6, where R5 is a single bond, or is a straight or branched alkylene group containing 1 to 6 carbons, and R6 is a straight or branched alkyl group containing 1-18 carbons, and if R1 is R3 --COO--R4, then R2 is H, a straight or branched alkyl group containing 1 to 18 carbons, or R5 --COO--R6. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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Specification