Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2001-08-31
2003-10-14
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S570000, C430S576000, C430S581000, C430S583000
Reexamination Certificate
active
06632597
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a novel methine dye compound, in particular a linked type methine dye compound in which two chromophores are linked, and a silver halide photographic material containing the same.
BACKGROUND OF THE INVENTION
The methine compound has so far been used in a silver halide photographic material as a spectral sensitizing dye. Techniques which have been well known as the techniques for improving the light absorptivity of silver halide grains are shown below. For improving the light absorptivity per one grain, it is necessary to increase the adsorption density of a sensitizing dye onto a silver halide grain, but generally used spectral sensitizing dyes are adsorbed onto the mono-molecular layer at almost the closest packing density and cannot be adsorbed beyond that.
Some techniques have been suggested for solving this problem. For example, P. B. Gilman, Jr., et al. made a cationic dye adsorb onto the first layer and further an anionic dye onto the second layer as described in
Photographic Science and Engineering,
Vol. 20, No. 3, p. 97 (1976). G. B. Bird, et al. made a plurality of dyes adsorb onto silver halide particles by multilayer adsorption and effected sensitization due to Forster type excitation energy transfer as disclosed in U.S. Pat. No. 3,622,316.
Sugimoto et al. performed spectral sensitization due to energy transfer from a luminescent dye in JP-A-63-138341 and JP-A-64-84244 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”).
These are all trials to intend to make a dye of the amount more than a saturation adsorption amount adsorb onto a silver halide grain, but any of these is not so effective to improve sensitivity. On the contrary, there are problems of the increase of intrinsic desensitization.
On the other hand, two-component linked dyes comprising two or more non-conjugated chromophores of dyes linked by covalent bonding are disclosed in U.S. Pat. Nos. 2,393,351, 2,425,772, 2,518,732,2,521,944, 2,592,196 and European Patent 565083. However, the objects of these patents were not to intend to increase a light absorptivity. As techniques which positively aimed at improving a light absorptivity, G. B. Bird et al. contrived sensitization by the contribution of energy transfer by the adsorption of linked type sensitizing dye molecules having a plurality of cyanine chromophores to thereby increase a light absorptivity as disclosed in U.S. Pat. Nos. 3,622,317 and 3,976,493, however, conspicuous sensitivity improvement has not been obtained as yet.
Ukai et al. suggest in JP-A-64-91134 to bond at least one substantially non-adsorptive dye containing at least two sulfo groups or carboxyl groups to a spectral sensitizing dye which is adsorbable onto a silver halide.
Further, Bishwakalma et al. performed spectral sensitization by using two-component linked dyes comprising a cyanine dye adsorptive onto silver halide and a non-adsorptive oxonol dye as disclosed in JP-A-6-27578, and Parton et al. by using two-component linked dyes comprising an adsorptive cyanine dye and a non-adsorptive merocyanine dye by a specific linking group as disclosed in EP-A-887700, but it cannot be said that sufficient improvement of sensitization by the contribution of energy transfer has been attained.
Thus, sufficient higher sensitization has not been achieved by any methods of the above patents and literature as yet and further technical development is required.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a novel methine linked dye and a high sensitivity silver halide photographic material containing the same.
The above object of the present invention has been achieved by the following means.
(1) A silver halide photographic material comprising a support having provided thereon at least one light-sensitive silver halide emulsion layer, wherein the emulsion layer contains a compound represented by the following formula (1):
wherein Dye 1 represents a first chromophore; Dye 2 represents a second chromophore; L
1
represents a linking chain; R
1
represents a dissociable group having pKa of 5 or less; m
1
represents an integer of from 1 to 5; m
2
represents an integer of from 1 to 5; and m
3
represents an integer of from 1 to 4.
(2) The silver halide photographic material as described in the above item (1), wherein R
1
in formula (1) represents —SO
3
M, —OSO
3
M, —PO
3
M
2
, —OPO
3
M
2
or —COOM, and M represents a proton or a cation.
(3) The silver halide photographic material as described in the above item (1) or (2), wherein L
1
in formula (1) is represented by -G
1
-(A
1
-G
2
-)
t1
-; G
1
and G
2
each represents an alkylene group or an alkenylene group; A
1
represents —O—, —S—, —SO
2
—, —NR
2
—, —COO—, —CONR
3
—, or —SO
2
NR
4
— regardless of the groups of both sides; R
2
, R
3
and R
4
each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group; t
1
represents an integer of from 1 to 10; and R
1
may substitute on any of G
1
, G
2
, R
2
, R
3
and R
4
.
(4) The silver halide photographic material as described in the above item (1), (2) or (3), wherein in the compound represented by formula (1), Dye 1 and Dye 2 each represents a cyanine chromophore, a merocyanine chromophore or an oxonol chromophore.
(5) The silver halide photographic material as described in any of the above items (1) to (4), wherein in the compound represented by formula (1), Dye 1 and Dye 2 each represents a cyanine chromophore or a merocyanine chromophore.
(6) The silver halide photographic material as described in any of the above items (1) to (5), wherein in the compound represented by formula (1), Dye 1 represents a cyanine chromophore and Dye 2 represents a cyanine chromophore or a merocyanine chromophore.
(7) The silver halide photographic material as described in any of the above items (1) to (6), wherein in the compound represented by formula (1), Dye 1 and Dye 2 each represents a cyanine chromophore.
(8) The silver halide photographic material as described in any of the above items (1) to (7), wherein the compound represented by formula (1) is represented by the following formula (2):
wherein G
1
, G
2
, A
1
and t
1
have the same meaning as described in the above item (3); R
1
represents —SO
3
M, —OSO
3
M, —PO
3
M
2
, —OPO
3
M
2
or —COOM; M represents a proton or a cation; m
3
represents an integer of from 1 to 4; R
1
may substitute on any of G
1
, G
2
and A
1
; X
1
, X
2
, X
3
and X
4
each represents —O—, —S—, —NR
5
— or —CR
6
R
7
—; R
5
, R
6
and R
7
each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group; R
11
, R
12
, R
13
and R
14
each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group; M
1
, M
2
, M
3
, M
4
, M
5
and M
6
each represents a methine group; n
1
and n
2
each represents an integer of from 0 to 3; V
1
, V
2
, V
3
and V
4
each represents a substituent; n
3
, n
4
, n
5
and n
6
each represents an integer of from 0 to 4, when n
3
, n
4
, n
5
and n6 each represents 2 or more, V
1
, V
2
, V
3
and V
4
may be the same or different, and they may be linked to each other to form a ring; CI represents an ion to neutralize electric charge; y represents a number necessary to neutralize electric charge; and G
1
is linked to Dye 1 via R
11
or V
1
, and G
2
is linked to Dye 2 via R
13
or V
3
.
(9) The silver halide photographic material as described in the above item (8), wherein in the compound represented by formula (2), X
1
and X
2
each represents —O— or —S—.
(10) The silver halide photographic material as described in the above item (8) or (9), wherein in the compound represented by formula (2), G
1
is linked to R
11
and G
2
is linked to R
13
.
(11) The silver halide photographic material as described in any of the above items (1) to (10), wherein in the compound represented by formula (1) or (2), the adsorptivity to a silver halide grain satisfies the following relationship:
Dye 1≧Dye 2
&
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