Radiation imagery chemistry: process – composition – or product th – Silver halide colloid tanning process – composition – or product
Reexamination Certificate
1994-03-10
2001-04-17
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Silver halide colloid tanning process, composition, or product
C430S265000, C430S486000
Reexamination Certificate
active
06218070
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention involves a process to make ultrahigh contrast negative images by using photosensitive recording materials with silver halide emulsions, and a means for performing the process.
2. Description of the Related Art
In reprography, continuous tone images must frequently be converted to halftone images. Silver halide materials are used for this purpose and are developed by special processes to an ultrahigh contrast, that is, to a maximum slope in the density curve of more than 10. Known examples are lithographic processes with low sulfite hydroquinone developers containing formaldehyde, developing with hydroquinone and a superadditive auxiliary developer in the presence of hydrazine compounds, or developing at relatively high pH in the presence of development inhibitors, such as tetrazole compounds.
Certain amino compounds are often used in these processes to further increase contrast. EP-00 32 456-B1 claims a method for processing a recording material, in the presence of a hydrazine compound, with a hydroquinone/3-pyrazolidinone developer containing an amino compound in a quantity to increase contrast.
EP-04 73 342-A1 describes a photographic silver halide material that can be developed to ultrahigh contrast in a developer with a pH<11. The photosensitive layer of this material contains a certain hydrazine compound and an amino or quaternary onium compound and is adjusted to a pH of at least 5.9.
Cationic surfactants and dyes with quaternary ammonium groups have long been known as development accelerators (L. F. A. Mason, “Photographic Processing Chemistry”, London and New York, 1966, page 41 ff). U.S. Pat. No. 4,135,931 describes the use of certain pyridinium compounds to accelerate lithographic development. However, contrast is not increased in these known uses.
Developers containing an amino compound to increase contrast have disadvantages. The required concentration of the amino compound is considerable and is often close to the solubility limit. The solubility limit can be easily exceeded as a result of a temperature increase or slight concentration changes from water evaporation during use, and the amino compound is liberated. This results in irregular development and contaminates the recording material and the developing machine. Because of their vapor volatility, the liberated amino compounds also reach other parts of the development machine and cause unwanted contamination and corrosion.
A very unpleasant odor occurs in the use of developers containing known amino compounds, due to the high required concentration and volatility of these compounds.
Because the amino compounds have limited solubility, it is difficult to formulate the usual commercial developer concentrates. EP-A-02 03 521 discloses that salts of certain sulfonic acids and carboxylic acids can be used as solubilizing agents. However, the other problems cited are not solved by such additives.
Known developers usually have a pH above 11. Therefore, they are not adequately stable in use, and they corrode parts of the development machine.
SUMMARY OF THE INVENTION
The problem involved in the invention is to make ultrahigh contrast negative images by a rapid process with a stable, odorless, and non-corrosive developer.
This problem is solved by a process to make ultrahigh contrast photographic negative images by developing, in the presence of an onium compound, a photosensitive recording material having at least one layer with a silver halide emulsion, characterized in that the molecule of the onium compound has at least one quaternary nitrogen atom and at least one tertiary amine function.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
The quaternary nitrogen atom can be incorporated, for example, in a quaternary ammonium or iminium group in an acyclic or cyclic structure or in a heterocyclic aromatic group. The tertiary amine function comprises another nitrogen atom with three substituents, two of which can also form a ring. The third substituent forms a bridge to the quaternary nitrogen atom. A molecule can also contain more than one quaternary nitrogen atom and tertiary amine function.
The onium compounds of the invention can comprise a cation of the generic formulas (I), (II), (III)
Q
+
—X—NR
1
R
2
(I)
R
1
R
2
N—X—Q
+
—Y—NR
3
R
4
(II)
R
1
R
2
N—X—Q
+
—A—Q
1
+
—Y—NR
3
R
4
(III)
and the anions necessary to balance the charge. In these formulas,
Q
+
, Q
1
+
are the same or different, each being a quaternary ammonium or iminium group formed incorporating X and optionally Y and A or an optionally substituted N-imidazolium, N-thiazolium, or N-pyridinium group,
X, Y, A are the same or different, each being an alkylene, hydroxyalkylene, alkyleneoxyalkylene, alkylenethioalkylene, alkyleneaminoalkylene, or hydroxyalkyleneoxyalkylene group, or a polyoxyalkylene chain, Y also being a single bond or an oxyalkylene, thioalkylene, or aminoalkylene group if it links to a carbon atom of an imidazolium, thiazolium, or pyridinium group, and
R
1
, R
2
, R
3
, R
4
are the same or different, each being an optionally substituted alkyl, alkoxy, alkylaryl, or phenyl group, with R
1
and R
2
as well as R
3
and R
4
also being capable of forming a ring.
The imidazolium, thiazolium, or pyridinium groups an be condensed with other aliphatic or aromatic ring systems, for example, to quinolinium, benzimidazolium, or benzthiazolium groups. They can also have other substituents, for example, alkyl groups, or functional groups, such as hydroxyl, mercapto, ester, and acid amide groups. In the case of the N-imidazolium group, such an additional substituent, preferably alkyl or substituted alkyl, is required on the other nitrogen atom to stabilize the quaternary structure, and the positive charge is not localized on one of the nitrogen atoms.
The groups X, Y, and/or A are preferably represented by chains in which the total number of carbon atoms and/or oxygen atoms plus nitrogen atoms plus sulfur atoms is 2 to 16, and Y in the above-cited special case can also be a single bond.
The alkyl groups in the R
1
, R
2
, R
3
, R
4
radicals have preferably 1 to 4 carbon atoms in a straight or branched chain. These can also form rings pairwise, insofar as this is spatially possible, for example, R
1
with R
2
and R
3
with R
4
. When Q
+
or Q
1
+
are quaternary ammonium or iminium groups, R
1
or R
3
can also form a ring with a radical on the nitrogen.
Examples of quaternary ammonium groups are
—N
+
R
5
R
6
R
7
(I-A)
wherein R
5
, R
6
, and R
7
are alkyl, alkenyl, or alkinyl with 1 to 10 carbon atoms, R
5
is such a group with 1 to 20 carbon atoms or aralkyl, and R
6
and R
7
can also form a ring with 4 to 8 carbon atoms, and
—N
+
R
8
R
9
—A—N
+
R
10
R
11
— (III-A)
wherein R
8
and R
10
are the same as R
5
, R
9
and R
11
are the same as R
6
, A is the same as for Formula (III), and R
8
with R
10
as well as R
9
with R
11
can be linked in each case to a chain with 2 to 10 carbon atoms. An example of a cyclic, cationic group according to Formula (III) or (III-A) is the doubly quaternized 1,1-diazabicyclo(2.2.2)-octane.
An example of a quaternary iminium group is
—N
+
R
12
=CR
13
—R
14
(I-B)
or
—N
+
R
12
=CR
13
—NR
1
R
2
(II-B)
wherein R
12
, R
13
, and R
14
are the same as R
5
, R
1
and R
2
are the same as in Formula (II), and two each of these groups can form a ring with 4 to 8 carbon or nitrogen atoms.
The anions can be the organic or inorganic anions usually employed for making organic salts in the number required for a balanced charge, for example, chloride, bromide, sulfate, nitrate, perchlorate, acetate, trifluoroacetate, and o-tosylate ions.
Examples of suitable onium compounds of the invention according to Formulas (I), (II), and (III) are:
The X or Y bridge links the tertiary amine nitrogen with the quaternary nitrogen of the Q
+
group. Such compounds can be prepared quite simply from easi
Agfa-Gevaert N.V.
Breiner & Breiner
Le Hoa Van
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