Thermochromic media
AssigneeMerck Patent GmbH
InventorsDavid Coates, Alison Linda May, Jacqueline Dawn Percy
Life of this patent
Estimating the term…
Abstract
An improved ink comprising a thermochromic liquid crystalline media comprising at least one optically inactive nematic component and at least one optically active component, the improvement wherein the optically active component comprises at least one menthol derivative of formula I ##STR1## wherein ##STR2## is 1,4-phenylene optionally substituted by up to 4 methyl group and/or halogen atoms, particularly fluorine atoms or is 1,4 cyclohexylene and MG is a mesogenic group, or forms a mesogenic group together with ##STR3##
Claims17
An improved thermochromic liquid crystalline medium comprising at least one optically inactive nematic component and at least one optically active component, wherein the optically active component comprises at least one compound of formula I having one menthyl group ##STR45## wherein ##STR46## is 1,4-phenylene optionally substituted by 1 to 4 methyl groups, halogen atoms or a combination thereof, or 1,4-cyclohexylene and
- MG is a group of formula II
- R.sup.1 --(A.sup.1 --Z.sup.1).sub.m --A.sup.2 --Z.sup.2 -- (II)
- wherein
- R.sup.1 is hydrogen or a straight-chained or branched alkyl or alkenyl group of 1 to 16 C atoms, wherein one or two nonadjacent CH.sub.2 groups are optionally replaced by --O--, --S--, --CO--O-- or --O--CO--, independently,
- A.sup.1 and A.sup.2 each independently denote:
- (a) 1,4-phenylene optionally substituted by 1 to 4 fluorine atoms, in which one or two CH groups may be replaced by N,
- (b) 1,4-cyclohexylene optionally substituted by --CN or --CH.sub.3, in which one or two CH.sub.2 groups may be replaced by O,
- (c) naphthalin-2,5-diyl or piperidin-1,4-diyl,
- Z.sup.1 and Z.sup.2 are each independently --CO--O--, --O--CO--, --CH.sub.2 O--, --OCH.sub.2 --, --N.dbd.CH--, --CH.dbd.N--, --CH.sub.2 CH.sub.2 --, --C--C.tbd. or a single bond and
- m is 0, 1 or 2
- and wherein the optically inactive nematic component comprises at least one compound selected from the formula III to VII ##STR47## wherein R.sup.2 and R.sup.3 each independently is hydrogen or a straight-chained or branched alkyl or alkenyl group of 1-16 C atoms, wherein one or two non-adjacent CH.sub.2 groups are optionally replaced by --O--, --S--, --CO--O-- or --O--CO--, independently,
- R.sup.4 has one of the meanings given for R.sup.2 and R.sup.3 or is halogen or cyano, ##STR48## each independently denote 1,4-phenylene or 1,4-cyclohexylene, n is 1 or 2, and
- o, p, q are each independently 0, 1 or 2.
An improved ink composition comprising a thermochromic liquid crystalline medium comprising at least one optically inactive nematic component and at least one optically active component, the improvement wherein the optically active component comprises at least one menthol derivative of formula I ##STR50## wherein ##STR51## is 1,4-phenylene optionally substituted by 1 to 4 methyl groups, halogen atoms, or a combination thereof, or 1,4-cyclohexylene and
- MG is a group of formula II
- R.sup.1 --(A.sup.1 --Z.sup.1).sub.m --A.sup.2 --Z.sup.2 -- (II)
- wherein
- R.sup.1 is hydrogen or a straight-chained or branched alkyl or alkenyl group of 1 to 16 C atoms, wherein one or two nonadjacent CH.sub.2 groups are optionally replaced by --O--, --S--, --CO--O-- or --O--CO--, independently,
- A.sup.1 and A.sup.2 each independently denote:
- (a) 1,4-phenylene optionally substituted by 1 to 4 fluorine atoms, in which one or two CH groups may be replaced by N,
- (b) 1,4-cyclohexylene optionally substituted by --CN or --CH.sub.3, in which one or two CH.sub.2 groups may be replaced by O,
- (c) naphthalin-2,5-diyl or piperidin-1,4-diyl,
- Z.sup.1 and Z.sup.2 are each independently --CO--O--, --O--CO--, --CH.sub.2 O--, --OCH.sub.2 --, --N.dbd.CH--, --CH.dbd.N--, --CH.sub.2 CH.sub.2 --, --C.tbd.C-- or a single bond and
- m is 0, 1 or 2.
Dependencies are inferred from the claim text.