Heat sensitive recording material, and color developer
The presently claimed invention relates to a color developer, a process for its manufacture and its use as a component in heat sensitive recording material. The heat sensitive recording material is useful for thermographic printing.
1. A compound of formula (I)
wherein
R and R 1 are independently selected from the group of
linear or branched C 1 -C 18 -alkyl,
R 11 O-R 12 — wherein R 11 and R 12 are independently linear or branched C 1 -C 8 -alkyl,
(R 13 ) 2 N—R 12 — wherein R 13 is a linear or branched C 1 -C 8 -alkyl or together with the nitrogen to which they are attached form a 5 or 6 membered ring, and
a radical of formula (II)
wherein, R 2 , R 3 , R 4 , R 5 , and R 6 are independently selected from the group of
hydrogen,
linear or branched C 1 -C 8 -alkyl,
—NH—C(═O)—R 14 , —C(═O)—NH—R 14 , wherein R 14 is linear or branched C 1 -C 8 -alkyl,
—C(═O)OR 15 , wherein R 15 is linear or branched C 1 -C 8 -alkyl, and
halogen, or
R 2 and R 3 , or R 4 and R 5 or both, or
R 3 and R 4 , or R 5 and R 6 or both, or
R 2 and R 3 as well as R 5 and R 6 together form a hydrocarbon diradical comprising 3 or 4 carbon atoms;
and
Q is a single bond or branched or unbranched C 1 -C 8 -alkylene, optionally comprising one or more oxygen atoms;
with the proviso that at least one of R or R 1 is a radical of formula (II).
2. The compound according to claim 1 ,
wherein
R and R 1 are independently
a radical of formula (II)
wherein, R 2 , R 3 , R 4 , R 5 , and R 6 are independently selected from the group of
hydrogen, and
linear or branched C 1 -C 8 -alkyl,
and
Q is a single bond.
3. The compound according to claim 1 wherein the compound is of formula (III)
4. The compound according to claim 3 , wherein the compound is a crystalline polymorph form α that is characterized by an X-ray powder diffraction pattern comprising 2Θ reflections, plus or minus 0.2 degrees 2Θ 0 , at 5.5, 6.1, 6.4, 12.1, 16.1, 16.8, 17.1, 18.3, 19.1, 19.9, 20.2, 21.4, 22.1, 22.7, 23.3, 24.3, 24.7, 25.0, 26.4, 27.7 and 29.3.
5. The compound according to claim 3 , wherein the compound is a crystalline polymorph form β that is characterized by an X-ray powder diffraction pattern comprising 2Θ reflections, plus or minus 0.2 degrees 2Θ, at 6.2, 8.1, 10.1, 11.8, 12.2, 13.4, 14.1, 15.3, 16.1, 17.2, 18.4, 19.1, 20.6, 21.4, 22.4, 24.5, 25.0, 25.9, 26.2, 26.9 and 28.4.
6. A process for preparing a compound according to claim 1 comprising the following steps,
a) chlorinating a sulfo-isophthalic compound (IVa) with a chlorination agent to obtain an acid chloride of formula (IVb),
wherein Z stands for hydrogen or an alkali metal;
b) optionally, isolating the acid chloride (IVb);
c) reacting the acid chloride (IVb) with at least one amine to obtain the compound of formula (I).
7. The process according to claim 6 , wherein the chlorination agent is selected from the group of thionyl chloride, POCl 3 , PCl 5 and oxalyl chloride.
8. The process according to claim 6 , wherein acid chloride (IVb) is 5-sulfonylchloride-isophthalic acid dichloride.
9. The process according to claim 6 , wherein the at least one amine is selected from the group of
linear or branched C 1 -C 18 -alkylamine,
R 11 O—R 12 —NH 2 , wherein R 11 and R 12 are independently linear or branched C 1 -C 8 -alkyl,
(R 13 ) 2 N—R 12 —NH 2 , wherein R 13 is a linear or branched C 1 -C 8 -alkyl or together with the nitrogen to which they are attached form a 5 or 6 membered ring, and
an amine of formula (IIa)
wherein, R 2 , R 3 , R 4 , R 5 , and R 6 are independently selected from the group of
hydrogen,
linear or branched C 1 -C 8 -alkyl,
—NH—C(═O)—R 14 , —C(═O)—NH—R 14 , wherein R 14 is linear or branched C 1 -C 8 -alkyl,
—C(═O)OR 15 , wherein R 15 is linear or branched C 1 -C 8 -alkyl, and
halogen, or
R 2 and R 3 , or R 4 and R 5 or both, or
R 3 and R 4 , or R 5 and R 6 or both, or
R 2 and R 3 as well as R 5 and R 6 together form a hydrocarbon diradical comprising 3 or 4 carbon atoms;
and
Q is a single bond or branched or unbranched C 1 -C 8 -alkylene, optionally comprising one or more oxygen atoms,
with the proviso that at least one of R or R 1 is a radical of formula (II) in the product of formula (I).
10. The process according to claim 6 , wherein step c) comprises reacting the acid chloride of formula (IVb) with an amine RNH 2 to obtain a compound of formula (I), wherein R 1 is identical to R.
11. The process according to claim 6 , wherein the amine is m-toluidine.
12. The process according to claim 6 , wherein step c) comprises the following sub-steps,
i) reacting an acid chloride of formula (IVb) with a first amine R 1 NH 2 to obtain a compound of formula (V),
ii) reacting the product obtained in substep i) with a second amine RNH 2 to obtain a compound of formula (I) wherein R and R 1 are different.
13. A heat sensitive recording material comprising
A) at least one color former, and
B) at least one color developer of formula (I)
wherein R and R 1 are defined as in claim 1 .
14. The heat sensitive recording material according to claim 13 , wherein the weight ratio of color developer to color former is in the range of 1.5:1 to 3:1.
15. The heat sensitive recording material according to claim 13 further comprising at least one sensitizer.
16. The heat sensitive recording material according to claim 15 , wherein the weight ratio of color developer to sensitizer is in the range of 0.5:1 to 1.5:1.
17. The heat sensitive recording material according to claim 13 further comprising at least one stabilizer.
18. The compound according to claim 1 , wherein R and R 1 are independently selected from the group of
—R 11 O—R 12 — wherein R 11 and R 12 are independently linear or branched C 1 -C 8 -alkyl,
—(R 13 ) 2 N—R 12 — wherein R 13 is a linear or branched C 1 -C 8 -alkyl or together with the nitrogen to which they are attached form a 5 or 6 membered ring, and
a radical of formula (II)
wherein, R 2 , R 3 , R 4 , R 5 , and R 6 are independently selected from the group of
hydrogen,
linear or branched C 1 -C 8 -alkyl,
—NH—C(═O)—R 14 , —C(═O)—NH—R 14 , wherein R 14 is linear or branched C 1 -C 8 -alkyl,
—C(═O)OR 15 , wherein R 15 is linear or branched C 1 -C 8 -alkyl, and
halogen, or
R 2 and R 3 , or R 4 and R 5 or both, or
R 3 and R 4 , or R 5 and R 6 or both, or
R 2 and R 3 as well as R 5 and R 6 together form a hydrocarbon diradical comprising 3 or 4 carbon atoms;
and
Q is a single bond or branched or unbranched C 1 -C 8 -alkylene, optionally comprising one or more oxygen atoms.
19. The compound according to claim 1 , wherein R and R 1 are independently selected from the group of
radicals of formula (II)
wherein, R 2 , R 3 , R 4 , R 5 , and R 6 are independently selected from the group of
hydrogen,
linear or branched C 1 -C 8 -alkyl,
—NH—C(═O)—R 14 , —C(═O)—NH—R 14 , wherein R 14 is linear or branched C 1 -C 8 -alkyl,
—C(═O)OR 15 , wherein R 15 is linear or branched C 1 -C 8 -alkyl, and
halogen, or
R 2 and R 3 , or R 4 and R 5 or both, or
R 3 and R 4 , or R 5 and R 6 or both, or
R 2 and R 3 as well as R 5 and R 6 together form a hydrocarbon diradical comprising 3 or 4 carbon atoms;
and
Q is a single bond or branched or unbranched C 1 -C 8 -alkylene, optionally comprising one or more oxygen atoms.