U.S. patent number 3,663,230 [Application Number 04/832,478] was granted by the patent office on 1972-05-16 for light-sensitive silver halide photographic emulsions.
This patent grant is currently assigned to Konishiroku Photo Industry Co., Ltd.. Invention is credited to Masao Ishihara, Eiichi Sakamoto, Shui Sato, Masayuki Shono, Osakazu Sugino.
|United States Patent
|Sato , et al.
||May 16, 1972
LIGHT-SENSITIVE SILVER HALIDE PHOTOGRAPHIC EMULSIONS
An ethylene oxide addition polymer of an alkylphenol-
formaldehyde condensate, said polymer consisting of the recurrent
structural unit of the formula ##SPC1## Wherein R.sub.1 is an alkyl
group; R.sub.2 is an alkyl group or a hydrogen atom; and n is an
integer of 1 to 100, and having an average polymerization degree in
the range of 2 to 10, has been found effective as a sensitizer for
a light-sensitive silver halide photographic emulsion, without
causing any adverse effect on photographic properties.
||Sato; Shui (Tokyo,
JA), Ishihara; Masao (Tokyo, JA), Sakamoto;
Eiichi (Hanno-shi, JA), Shono; Masayuki (Tokyo,
JA), Sugino; Osakazu (Tokyo, JA)
||Konishiroku Photo Industry Co.,
Ltd. (Tokyo, JA)
||June 11, 1969
Foreign Application Priority Data
|Jun 12, 1968 [JA]
1/04 (20060101); G03C 1/043 (20060101); G03c
001/28 (); G03c 001/34 (); G03c 001/04 ()
U.S. Patent Documents
Torchin; Norman G.
Fichter; Richard E.
What we claim is:
1. A light-sensitive silver halide photographic emulsion which
contains a sensitizing amount of an ethylene oxide addition polymer
of an alkylphenol-formaldehyde condensate, said polymer consisting
of the recurrent structural unit of the formula ##SPC4##
wherein R.sub.1 is an alkyl group; R.sub.2 is an alkyl group or a
hydrogen atom; and n is an integer of 1 to 100, and having an
average polymerization degree in the range of 2 to 10.
2. A light-sensitive silver halide photographic emulsion as claimed
in claim 1, further comprising a color coupler.
3. A light-sensitive silver halide photographic emulsion as claimed
in claim 1, wherein said emulsion has been sensitized by way of
noble metal sensitizers, sulfur sensitizers, reduction sensitizers
or polyalkylene oxide type sensitizers.
4. A light-sensitive silver halide photographic emulsion as claimed
in claim 1, further including stabilizers, surface active agents,
coating aids or hardeners.
5. A light-sensitive silver halide color photographic material
which comprises a film support and, coated thereon, a layer of the
emulsion as claimed in claim 2.
This invention relates to the enhancement in light sensitivity of
light-sensitive silver halide photographic emulsions. More
particularly, the invention pertains to light-sensitive silver
halide photographic emulsions containing ethylene oxide addition
polymers of alkylphenol-formaldehyde condensates.
Heretofore, there have been proposed many processes for enhancing
the light sensitivity of light-sensitive silver halide emulsions.
Typical as such processes are chemical sensitization processes
using sulfur compounds capable of forming silver sulfide, or using
suitable reducing substances or noble metal salts. Further, it is
well known that the light sensitivity can be further increased by
using a combination of said compounds. [Refer to, for example, "The
Theory of The Photographic Process," 3rd Edition (1967), pages
113-117]. Another well known chemical sensitization process is the
process using polyalkylene oxide compounds having a molecular
weight of at least 300. However, all these known sensitizers are
restricted in the amount to be added to emulsions and, in case the
amounts thereof exceed a definite limit, there are brought about
such drawbacks that photographic films prepared by use of such
emulsions are greatly increased in fog and are low in stability
during storage at high temperatures. Moreover, there are such
difficulties that the fog is high in degree and cannot be
controlled even when anti-fogging agents are incorporated into the
In view of the above, the present inventors made various studies to
find that when ethylene oxide addition polymers of
alkylphenol-formaldehyde condensates are incorporated into
photographic silver halide emulsion layers or into layers adjacent
to said emulsion layers, the films can be increased in gamma,
effective sensitivity and maximum density with good stability and
without fogging even when the films have been stored at high
The compounds employed in the present invention have such features
that they do not increase fog of silver halide emulsions due to
lapse of time, are scarcely increased in amount to be added and
hence are easily usable, and can improve the characteristics of
photographic emulsions. Particularly, they show such prominent
effects that they can give marked increase in maximum density and
gamma which cannot be attained by use of conventional polyalkylene
The ethylene oxide addition polymers of
alkylene-phenol-formaldehyde condensates employed in the present
invention are formed by the polymerization of structural units
represented by the formula, ##SPC2##
WHEREIN R.sub.1 is an alkyl group; R.sub.2 is an alkyl group or a
hydrogen atom; and n is an integer of 1 to 100, and those in which
said structural units have been polymerized to an average
polymerization degree in the range of 2 to 10 are preferable. These
polymers are such that all the alkyl groups represented by R.sub.1
which are bonded to benzene nuclei of the structural units may be
same or different. These compounds can be synthesized according to
the methods disclosed in U.S. Pat. No. 2,454,541. Generally, the
compounds are viscous paste-like, wax-like or semi-solid resins,
and are soluble in water, acetone, alcohol, benzene and the
Typical as such compounds are set forth below, but compounds usable
in the present invention are not limited to these.
Compound 1: Compound prepared by addition-polymerizing
p-cresol-formaldehyde resin with 1.5 moles of ethylene oxide.
Compound 2: Compound prepared by addition-polymerizing
p-cresol-formaldehyde resin with 8 moles of ethylene oxide.
Compound 3: Compound prepared by addition-polymerizing
nonylphenol-formaldehyde resin with 16 moles of ethylene oxide.
Compound 4: Compound prepared by addition-polymerizing
octylphenol-formaldehyde resin with 15 moles of ethylene oxide.
Compound 5: Compound prepared by addition-polymerizing
p-octadecylphenol-formaldehyde resin with 100 moles of ethylene
oxide. m.p. 58.degree.-59.degree. C.
Compound 6: Compound prepared by addition-polymerizing
nonylphenol-p-cresol-formaldehyde resin with 15 moles of ethylene
oxide. n.sup.20.sub.D 14904.
Compound 7: Compound prepared by addition-polymerizing
p-nonylphenol-dinonylphenol-formaldehyde resin with 30 moles of
ethylene oxide. n.sup.20.sub.D 14896.
The compounds employed in the present invention may be added at any
time during the second ripening step. Ordinarily, however, it is
preferable to add after completion of the second ripening. In
adding the compounds, they are dissolved in water or in a
water-miscible organic solvent such as methanol or ethanol and are
added to photographic emulsion layers or layers adjacent thereto.
The amounts of the compounds to be added vary depending on the kind
of the compounds or light-sensitive materials employed, but are
ordinarily within the range of 0.01 g. -- 3 g. per kg. of silver
The compounds employed in the present invention can be applied to
any type of silver halide emulsions such as silver chlorobromide,
silver iodobromide and the like emulsions. These emulsions may have
been subjected to gold sensitization, chemical sensitization, or
spectral sensitization or supersenitization by use of spectral
sensitizing dyes. Further, they may have been incorporated with
various types of stabilizers, hardeners and surface active
The compounds employed in the present invention are applicable not
only to black and white photographic emulsions but also to color
photographic emulsions containing couplers.
The present invention will be illustrated in detail below with
reference to examples.
An emulsion for neutral process negative comprising 5 mole percent
of silver iodide and 95 mole percent of silver bromide was
subjected to second ripening to attain the maximum sensitivity by
means of a sulfur sensitizer and a gold sensitizer. Thereafter, the
emulsion was divided into portions of 100 g. each in weight. To
each of the divided emulsions were individually added the present
compounds shown in Table 1. After adding a suitable amount of
saponin as a coating aid, each emulsion was uniformly coated under
the same conditions onto a cellulose triacetate film base to
prepare a sample. The sample was exposed to light by means of a
sensitometer KS-1 (Manufactured and sold by Konishiroku Photo
Industry Co., Ltd.) at 160 Lux, 5,400.degree. K and was then
developed at 20.degree. C. for 5 minutes with a developer of the
Metol 3 g. Anhydrous sodium sulfite 50 g. Hydroquinone 6 g. Sodium
carbonate (monohydrate) 29.5 g. Potassium bromide 1 g. Water to
make 1,000 cc. (In application, the developer was diluted with
water to 1 : 1).
Thereafter, each sample was subjected to sensitometry to obtain the
results set forth in Table 1.
Amount Sample Compound mg/100 g. Sensi- Maximum No. added emulsion
tivity Gamma density Fog
1 Compound 2 60 107 0.90 2.10 0.06 2 Compound 4 60 120 1.00 2.29
0.06 3 Compound 6 60 124 1.10 2.31 0.07 4 Non-addition 0 100 0.80
In the table, the sensitivity was represented by a relative
sensitivity measured in the case where the sensitivity of
non-addition compound (Sample No. 4) was regarded as 100.
As is clear from Table 1, it is understood that in accordance with
the present invention, light-sensitive photographic materials
improved in sensitivity, gamma and maximum density can be
The same high sensitivity emulsion as in Example 1 was divided,
after completion of the second ripening, into portions of 100 g.
each in weight. To each portion were individually added the present
compounds as set forth in Table 2. Subsequently, 20 mg. per 100 g.
of emulsion of 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene as a
stabilizer was added, and then suitable amounts of a hardener and a
coating aid were added to prepare an emulsion. This emulsion was
uniformly coated on a cellulose triacetate film base and was then
dried. Samples obtained in the above manner were subjected to
incubation test at high temperature and humidity to obtain the
results as set forth in Table 2. For comparison, a compound of the
(disclosed in British Pat. No. 805,826) was used to prepare a
The samples in accordance with the present invention give excellent
light-sensitive photographic materials which are less in formation
of fog due to lapse of time and free from degradation in
sensitivity even when stored under severe conditions. ##SPC3##
A silver iodobromide color photographic emulsion containing 4 mole
percent of silver iodide was subjected to gold sensitization and
sulfur sensitization to effect second ripening. Immediately before
completion of the ripening, the emulsion was divided into portions
of 100 g. each in weight, and the present compounds as shown in
Table 3 were individually added to each of the divided emulsions.
After completion of the ripening, each emulsion was charged with a
solution prepared by dissolving at an elevated temperature
as an internal cyan coupler in a mixture of di-N-butyl phthalate
and ethyl acetate, and was emulsified and dispersed by use of
sodium alkylbenzenesulfonate in a gelatine solution. Subsequently,
the emulsion was incorporated with a hardener, and was then
uniformly coated on a cellulose triacetate film support, followed
by drying, to prepare a sample. Each sample thus prepared was
exposed in the same manner as in Example 1 and was then developed
at 20.degree. C. for 10 minutes with a color developer of the
sulfate 5.0 g. Sodium sulfite (anhydrous) 2.0 g. Sodium carbonate
(monohydrate) 50 g. Potassium bromide 1.0 g. Benzyl alcohol 3.8 g.
Sodium hydroxide 5.5 g. Water to make 1,000 cc.
Thereafter, each sample was subjected to ordinary stopping, fixing,
water-washing and bleaching treatments, was washed with flowing
water for 20 minutes and was then dried to obtain a cyan image. The
thus obtained cyan image was subjected to sensitometry to obtain
the results as set forth in Table 3.
Amount Sample (mg/100 g. Sensi- No. Compound added emulsion) tivity
9 Compound 3 100 120 0.92 0.03 10 Compound 3 50 115 0.90 0.03 11
Non-addition -- 100 0.70 0.03
In the table, the sensitivity is a relative sensitivity measured by
assuming that the sample prepared without the addition of the
present compound was 100.
From the table, it is understood that the present compounds are
effectively applied also to coupler-containing emulsions.
* * * * *