Record receiver having plural interactive leaves or a colorless – Having a colorless color-former – developer therefor – or... – Method of use – kit – or combined with marking instrument or...
Reexamination Certificate
2001-10-26
2003-11-11
Hess, Bruce (Department: 1774)
Record receiver having plural interactive leaves or a colorless
Having a colorless color-former, developer therefor, or...
Method of use, kit, or combined with marking instrument or...
C503S217000
Reexamination Certificate
active
06645909
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for a diazo color formation reaction and a recording material utilizing the same, and more particularly, it relates to a process for an azo coupling reaction having a large reaction rate to realize quick color formation, and a recording material having a large color formation rate utilizing the reaction.
2. Description of the Related Art
Many reports have been made with respect to a reaction using a coupler and a diazonium salt and a recording material utilizing the color formation reaction. However, there are very few examples that use a coupler having a releasing group at the coupling site.
For example,
J. Chem. Soc., Perkin Trans.,
2 (1982) discloses a coupling reaction of an indole coupler having a releasing group at the coupling site and a p-nitrobenzene diazonium salt. However, the coupler having a releasing group introduced exhibits a remarkably low coupling rate in comparison to a non-substituted compound.
JP-A-6-297857 discloses an azo coupling reaction of a naphthol coupler having a dimethylaminomethyl group at the coupling site and a benzene diazonium salt. However, the color formation reaction has a problem in that a sufficient dye density cannot be obtained.
In addition to these report, it has been the general recognition that in the diazo color formation reaction system, introduction of a releasing group at the coupling site lowers the coupling activity.
Furthermore, a coupler having a releasing group has been widely studied and reported in many articles with respect to a coupler for photographic purposes using silver halide (for example, as described in
Kaitei Shashin Kougaku no Kiso, Gin'en Shashin hen
(Basis of Photographic Engineering, Revised Edition, Volume for Silver Halide Photograph), published by Corona Publishing Co., Ltd.
However, the releasing groups in the reports relating to a recording material using silver halide are defined as groups that can be released through reaction with an oxidized product of a coloring developing agent, such as quinone diimine. However, there have been no reports describing a compound having a group that can be released through reaction with a diazonium salt.
In the color formation reaction using a reaction of a coupler and a diazonium salt, the color formation reaction rate (i.e., the coupling rate) is one of the important characteristic features. For example, in a heat-sensitive recording material using a diazonium salt, a certain degree of speed of the reaction rate in azo coupling is demanded from the standpoint of practical recording rate. In general, the coupling rate is roughly defined by the skeleton of the coupler as assuming that the same diazonium salt is used. Therefore, the coupling rate can be increased by appropriately changing the species of the substituents on the positions other than the coupling site, but the stability of the coupler is then lowered to cause various problems. For example, a heat-sensitive recording material suffers a problem in that the exposure coloring on the background part of a coupler having a good reaction rate tends to be increased.
Consequently, the coupling activity and the stability of the coupler tend to counter each other. Therefore, such a method has not yet been found that is effective to greatly improve the coupling activity of a certain coupler skeleton without greatly impairing the stability of the coupler.
SUMMARY OF THE INVENTION
The present invention has been developed to solve the problems associated with the conventional techniques described in the foregoing and to attain the following object.
An object of the present invention is to provide a process for an azo coupling reaction with high coupling activity using a stable coupler having a large reaction rate and an excellent coloring density, and also is to provide a recording material containing the coupler excellent in stability and reaction rate by utilizing the process for azo coupling reaction.
The inventors have found that the object is attained by a process for a diazo color formation reaction using the following coupler having a releasing group and a recording material containing the coupler, and thus the invention has been completed.
The process for an azo coupling reaction of the present invention comprises carrying out a coupling reaction of a diazonium salt and a coupler to make the diazonium salt form color, the coupler having one of the structures represented by the following general formulae (1), (2) and (3):
wherein X
1
, X
2
, X
3
and X
4
each independently represents an atomic group necessary for forming a 5-membered aromatic heterocyclic ring; Y represents an amino group, a substituted amino group, a hydroxyl group, an alkoxy group, an alkyl group, which may have a substituent, provided that X
1
and Y may be combined to form a heterocyclic ring; L represents a substituent capable of being released as a carbonium ion upon coupling with the diazonium salt; and EWG
1
and EWG
2
each independently represents an electron withdrawing group, provided that EWG
1
and EWG
2
may be combined to form a heterocyclic ring.
It is preferable that the substituent represented by L of the coupler is a substituent represented by the following general formula (4):
—CHR
1
R
2
wherein at least one of R
1
and R
2
contains an electron sourse capable of stabilizing a carbonium ion by resonance, i.e., a heteroatom having an unpaired electron.
It is preferable that the 5-membered heterocyclic ring of the coupler having a structure represented by the general formula (1) or (2) is one of a pyrrole ring, a pyrazole ring and an imidazole ring.
It is preferable that EWG
1
and EWG
2
of the coupler having a structure represented by the general formula (3) each is a carbonyl group.
It is preferable that the diazonium salt as the other component involving the azo coupling reaction of the invention is a benzene diazonium salt represented by the following general formula (5):
wherein R
3
, R
4
and R
5
, which may be the same or different, each independently represents an alkyl group, an aryl group, an aralkyl group, an alkenyl group, a heterocyclic group or an acyl group; Y
1
represents an oxygen atom, a sulfur atom or an amino group; Y
2
represents an oxygen atom or a sulfur atom; Y
3
represents an oxygen atom, a sulfur atom or a hydrogen atom, provided that when Y
3
represents a hydrogen atom, R
5
is not present; and X
−
represents an anion.
In the process for an azo coupling reaction of the present invention, it is preferable that a reaction rate of the reaction k is 0.1 (s
−1
) or more. When the process for an azo coupling reaction of the present invention is employed, the color formation reaction of the diazonium salt and the coupler effectively proceeds owing to the excellent stability and the large reaction rate, and thus the coloring density of the diazonium salt used is sufficiently exerted. When the coloring rate is small, on the other hand, the probability of inactivation of the diazo compound with the lapse of time during the reaction increases, and thus sufficient coloring density is difficult to be obtained.
The recording material of the present invention comprises a coupler having one of the structures represented by the following general formulae (1), (2) and (3), and a diazonium salt capable of coloring through a coupling reaction with the coupler.
As preferable embodiments of the recording material, it is preferable that the diazonium salt is encapsulated in microcapsules, and it is more preferable from the standpoint of reactivity that an emulsion containing the coupler contains an organic base.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A process for an azo coupling reaction of the present invention using a diazonium salt and a coupler having a releasing group, and a recording material containing the coupler will be described below.
Process for Azo Coupling Reaction
Coupler Having Releasing Group
When a coupler that is coupled with a diazonium salt in an ordinary method for an azo co
Fujita Akinori
Matsushita Tetsunori
Fuji Photo Film Co. , Ltd.
Hess Bruce
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