U.S. patent number 3,816,129 [Application Number 05/320,450] was granted by the patent office on 1974-06-11 for synthetic silver halide emulsion binder.
This patent grant is currently assigned to Polaroid Corporation. Invention is credited to Maurice J. Fitzgerald.
United States Patent |
3,816,129 |
Fitzgerald |
June 11, 1974 |
SYNTHETIC SILVER HALIDE EMULSION BINDER
Abstract
A photosensitive silver halide emulsion wherein the emulsion
binder comprises a graft copolymer of a quaternary ammonium alkyl
acrylate salt on a polyhydroxy-substituted polymer.
Inventors: |
Fitzgerald; Maurice J. (Canton,
MA) |
Assignee: |
Polaroid Corporation
(Cambridge, MA)
|
Family
ID: |
23246487 |
Appl.
No.: |
05/320,450 |
Filed: |
January 2, 1973 |
Current U.S.
Class: |
430/569; 430/627;
430/630; 430/570; 430/599; 430/628 |
Current CPC
Class: |
C08F
291/08 (20130101); G03C 1/053 (20130101); C08F
291/08 (20130101); C08F 220/34 (20130101) |
Current International
Class: |
C08F
291/08 (20060101); C08F 291/00 (20060101); G03C
1/053 (20060101); G03c 001/72 (); G03c 001/28 ();
G03c 001/02 () |
Field of
Search: |
;96/114,114.3,113 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Smith; Ronald H.
Assistant Examiner: Schilling; Richard L.
Claims
What is claimed is:
1. A photosensitive silver halide emulsion wherein the emulsion
binder comprises a water-soluble film-forming copolymer of a
polyhydroxy-substituted polymer having grafted thereon a monomer of
the formula: ##SPC50##
wherein R.sub.1 is hydrogen, a lower alkyl group or a halogen;
R.sub.2 is hydrogen, a lower alkyl group, a halogen or cyano group;
R.sub.3 is a lower alkylene or lower cycloalkylene group; R.sub.4,
R.sub.5, and R.sub.6 each is a lower alkyl group or a lower
cycloalkyl group, or R.sub.3 and/or R.sub.4 and/or R.sub.5 and/or
R.sub.6 taken together represent the atoms necessary to complete a
3 to 8-membered heterocyclic ring structure; and X is a
salt-forming anion.
2. The product as defined in claim 1 wherein substantially all of
said emulsion binder comprises said graft copolymer.
3. The product as defined in claim 1 wherein said graft copolymer
comprises about 5 to 75 mole percent of said monomer.
4. The product as defined in claim 3 wherein said graft copolymer
comprises about 20 mole percent of said monomer.
5. The product as defined in claim 1 wherein said silver halide
emulsion is a silver iodobromide emulsion.
6. The product as defined in claim 1 wherein said emulsion includes
at least one chemical sensitizing agent.
7. The product as defined in claim 1 wherein said emulsion includes
at least one optical sensitizing agent.
8. The product as defined in claim 1 wherein said monomer is
3-(methacryloyloxy-2-hydroxyprop-1-yl trimethylammonium
chloride.
9. The product as defined in claim 1 wherein said monomer is
.beta.-(methacryloyloxy)ethyl trimethylammoniummethyl sulfate.
10. The product as defined in claim 1 wherein said
polyhydroxy-substituted polymer is polyvinyl alcohol.
11. The product as defined in claim 1 wherein said graft copolymer
includes a second ethylenically unsaturated monomer.
12. The product as defined in claim 11 wherein said second monomer
is acrylamide.
13. The product as defined in claim 11 wherein said second monomer
is N-isopropyl acrylamide.
14. The product as defined in claim 1 wherein said emulsion
includes a bodying polymer.
15. The product as defined in claim 14 wherein said bodying polymer
is gelatin.
16. The product as defined in claim 14 wherein said bodying polymer
is polyvinyl alcohol.
17. A method of preparing a photosensitive silver halide emulsion
which comprises reacting a water-soluble silver salt with a
water-soluble halide salt in an aqueous solution containing a
water-soluble film-forming graft copolymer of a
polyhydroxy-substituted polymer having grafted thereon a monomer of
the formula: ##SPC51##
wherein R.sub.1 is hydrogen, a lower alkyl group or a halogen;
R.sub.2 is hydrogen, a lower alkyl group, a halogen or cyano group;
R.sub.3 is a lower alkylene or lower cycloalkylene group; R.sub.4,
R.sub.5, and R.sub.6 each is a lower alkyl group or a lower
cycloalkyl group, or R.sub.3 and/or R.sub.4 and/or R.sub.5 and/or
R.sub.6 taken together represent the atoms necessary to complete a
3 to 8-membered heterocyclic ring structure; and X is a
salt-forming anion.
18. The method as defined in claim 17 wherein said monomer is
3-(methacryloyloxy)-2-hydroxyprop-1-yl trimethylammonium
chloride.
19. The method as defined in claim 17 wherein said monomer is
.beta.-(methacryloyloxy)ethyl trimethylammonium methyl sulfate.
20. The method as defined in claim 17 wherein said
polyhydroxy-substituted polymer is polyvinyl alcohol.
21. The method as defined in claim 17 wherein said graft copolymer
includes a second ethylenically unsaturated monomer.
22. The method as defined in claim 21 wherein said second monomer
is acrylamide.
23. The method as defined in claim 20 wherein said second monomer
is N-isopropyl acrylamide.
Description
BACKGROUND OF THE INVENTION
This invention relates to photography and more particularly, to
novel photosensitive photographic elements, particularly novel
photosensitive emulsions.
As a result of the known disadvantages of gelatin, in particular,
its variable photographic properties and its fixed physical
properties, for example, its diffusion characteristics; much effort
has been expended in the past in order to replace gelatin with a
suitable synthetic colloid binder for photographic silver halide
emulsions. Many synthetic polymeric materials have heretofore been
suggested as peptizers for silver halide emulsions, however, these
have generally not functioned satisfactorily and frequently have
not fulfilled all of the basic requirements for a photosensitive
silver halide emulsion binder listed following:
1. absent (or constant) photographic activity;
2. ability to form an adsorption layer on microcrystals of silver
halide permitting stable suspensions to be obtained;
3. ability to form adsorption layers as described in 2 above which
do not prevent growth of silver halide microcrystals during
physical ripening; and
4. solubility in water solution.
In addition, hithertofore, much emphasis has been placed on the
ability of the synthetic polymeric material to mix with gelatin, as
this property has been critical for employment in partial
substitution reactions with gelatin. Consequently, many synthetic
polymers of the prior art have been materials which allow for the
growth of silver halide crystals only in the presence of
gelatin.
Graft copolymers of various types have been employed in the prior
art as gelatin substitutes in photographic silver halide emulsions;
however, these copolymers have included monomers quite different
from those employed in the present invention.
For example, Caldwell U.S. Pat. No. 2,843,562 discloses graft
copolymers of vinyl chloride on polyvinyl alcohol and related vinyl
alcohol polymers; Perry and Reynolds U.S. Pat. No. 3,425,836
describes graft copolymers suitable for silver halide dispersions
in the preparation of photographic emulsions wherein a quaternary
ammonium vinyl ether monomer is grafted onto a hydrophilic
polysaccharide; and my U.S. Pat. No. 3,681,079 describes a graft
copolymer emulsion binder wherein an aminoalkyl acrylate monomer is
grafted onto a polyhydroxy substituted polymer.
SUMMARY OF THE INVENTION
The present invention is directed to a photosensitive silver halide
emulsion wherein the silver halide crystals are disposed in a
synthetic polymeric binder comprising a water-soluble film-forming
graft copolymer of a quaternary ammonium alkyl acrylate monomer
represented by the formula: ##SPC1##
Wherein R.sub.1 is hydrogen, a lower alkyl group, i.e., 1-4 carbon
alkyl group, preferably methyl or ethyl, or a halogen, i.e.,
chloro, bromo, or iodo; R.sub.2 is hydrogen, a lower alkyl group, a
halogen or cyano group; R.sub.3 is a lower alkylene, i.e., 1-4
carbon alkylene group or a lower cycloalkylene group, i.e., 3-6
carbon cycloalkylene group; and R.sub.4, R.sub.5 and R.sub.6 each
is a lower alkyl or a lower cycloalkyl group, i.e., a 3-6 carbon
cycloalkyl group; or R.sub.3 and/or R.sub.4 and/or R.sub.5 and/or
R.sub.6 taken together represent the atoms necessary to complete a
3 to 8-membered heterocyclic ring structure; and X is a
salt-forming anion, e.g., halide, sulfate, alkylsulfonate,
arylsulfonate, nitrate, etc.; on a poly hydroxy substituted
polymer.
If desired, the graft copolymer may also include a second monomer
grafted thereon, i.e., an ethylenically unsaturated monomer. In
still another embodiment, the above-described polymer may comprise
only a portion of the binder, the remainder constituting gelatin or
a second synthetic polymer.
DETAILED DESCRIPTION OF THE INVENTION
As indicated, the present invention is directed to photosensitive
silver halide emulsions wherein photosensitive silver halide
crystals are disposed in a water-soluble film-forming synthetic
polymeric binder comprising a poly hydroxy-substituted polymer
having grafted thereon a quaternary ammonium alkyl acrylate monomer
represented by the formula set forth above. The term "film-forming"
is intended to designate a molecular weight sufficiently high to
form a film, for example, a molecular weight comparable to that of
gelatin (i.e., around 15,000).
The polymers of the present invention have been found to
substantially meet all of the basic requirements of a gelatin
substitute without possessing the above-described deficiencies of
gelatin. More specifically, the emulsions of the present invention
are more stable against degradation than gelatin; particularly
against hydrolysis of the polymeric backbone in acidic or basic
media. The emulsions of this invention also show a resistance to
the growth of microorganisms which is not exhibited by gelatin.
An important feature of the graft copolymers of this invention is
the presence of a mobile anion or "counter-ion" which is free to
diffuse in the aqueous medium of the silver halide emulsion. This
counter-ion may thus be used to introduce a photographically
advantageous reagent into the emulsion, for example, by providing a
counter-ion which is a photographic sensitizer, antifoggant,
stabilizer or the like. Of course, the counter-ion should be
selected by one practicing this invention so as to be compatible
with the silver halide emulsion and its intended usage; for
example, if a silver bromide emulsion were contemplated, one would
not use a polymeric binder with an iodide counter-ion since the
greater insolubility of the silver iodide would result in the
precipitation of silver iodide in preference to silver bromide.
With regard to the backbone polymer of the graft copolymer; in
general, any organic polymer comprising repeating units comprising
structural units containing a plurality of ##SPC2##
groupings capable of being oxidized by, e.g., a transition metal
ion catalyst is useful in the present invention. Preferred
backbones are substituted or unsubstituted cellulosic or polyvinyl
polymers, and most preferably, a backbone selected from the group
consisting of polymeric polyols, polyvinyl alcohol, gelatin,
polysaccharides, partial acetals of polyvinyl alcohol, etc.
It is believed that upon oxidation of the ##SPC3##
grouping, the free radical is formed, which attacks the double bond
of the quaternary ammonium salt monomer, thus initiating
polymerization.
As examples of such polyhydroxy-substituted polymers, mention may
be made of the following: ##SPC4##
wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6 and X
have the above-indicated definitions and which are contemplated as
being useful for employment in the instant invention for grafting
onto the polyhydroxy-substituted polymer, mention may be made of
the following: ##SPC5##
The instant graft copolymers may have, in addition to the
structures defined above, any compatible repeating unit or various
repeating units or additional grafted segments which are not
detrimental to photographic silver halide emulsions and which
permit the polymers to be soluble in water. Examples of typical
comonomers which may be employed include the following
ethylenically-unsaturated monomers:
54. CH.sub.2 =CH--COOH
acrylic acid
55. ##SPC6##
methacrylic acid
56. ##SPC7##
.alpha.-chloroacrylic acid
57. ##SPC8##
.alpha.-bromoacrylic acid
58. CH.sub.3 CH=CH--COOH
crotonic acid
59. CH.sub.3 CH=CH--COOH
isocrotonic acid
60. Cl--CH=CH--COOH
.beta.-chloroacrylic acid
61. Br--CH=CH--COOH
.beta.-bromoacrylic acid
62. ##SPC9##
.beta.-chloromethacrylic acid
63. CH.sub.2 =CH--COO--CH.sub.3
methyl acrylate
64. ##SPC10##
ethyl methacrylate
65. ##SPC11##
n-propyl-.alpha.-chloroacrylate
66. Br--CH=CH--COO--CH--CH.sub.3).sub.2
isopropyl-.beta.-bromoacrylate
67. ##SPC12##
isobutyl methacrylate
68. CH.sub.2 =CH--COO--CH.sub.2 CH.sub.2 OH
.beta.-hydroxyethyl acrylate
69. CH.sub.2 =CH--COO--CH.sub.2 CH.sub.2 CH.sub.2 OH
.gamma.-hydroxypropyl acrylate
70. ##SPC13##
2-hydroxy-n-propyl methacrylate
71. CH.sub.2 =CH--CO--NH.sub.2
acrylamide
72. ##SPC14##
.alpha.-chloroacrylamide
73. ##SPC15##
.alpha.-bromoacrylamide
74. ##SPC16##
methacrylamide
75. ##SPC17##
.alpha.-ethylacrylamide
76. ##SPC18##
.beta.-chloromethacrylamide
77. ##SPC19##
2,3-dibromoacrylamide
78. CH.sub.3 CH=CH--CO--NH.sub.2
crotonamide
79. ##SPC20##
N-methylmethacrylamide
80. CH.sub.2 =CH--CO--N--CH.sub.3).sub.2
N,n-dimethylacrylamide
81. ##SPC21##
N-ethyl-.alpha.-chloroacrylamide
82. CH.sub.2 CH=CO--NH--C--Ch.sub.3).sub.3
N-tertiary butylacrylamide
83. ##SPC22##
N-cyclohexylacrylamide
84. ##SPC23##
N-tertiary octyl acrylamide
85. CH.sub.2 =CH--CO--NH--CH.sub.2 OH
N-methylolacrylamide
86. CH.sub.2 =CH--CO--NH--CH.sub.2 CH.sub.2 OH
N-(.beta.-hydroxyethyl) acrylamide
87. ##SPC24##
diacetone acrylamide
88. CH.sub.2 =CH--CO--NH--CH--CH.sub.3).sub.2
N-isopropylacrylamide
89. ##SPC25##
N-benzylacrylamide
90. CH.sub.2 =CH--O--CH.sub.3
methylvinyl ether
91. ##SPC26##
ethyl .alpha.-chlorovinyl ether
92. CH.sub.2 =CH--O--CH.sub.2 CH.sub.2 Cl
.beta.-chloroethyl vinyl ether
93. CH.sub.2 =CH--O--CH.sub.2 CH.sub.2 --OCH.sub.3
.beta.-methoxyethyl vinyl ether
94. ##SPC27##
isobutyl isopropenyl ether
95. CH.sub.2 =CH--O--CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2
--CH--CH.sub.3).sub.2
isooctyl vinyl ether
96. ##SPC28##
methylvinyl ketone
97. ##SPC29##
ethyl isopropenyl ketone
98. ##SPC30##
n-propyl-.alpha.-chlorovinyl ketone
99. ##SPC31##
.beta.-methoxyethyl-.alpha.-bromovinyl ketone
100. ##SPC32##
.beta.-hydroxyethyl-1-butene-2-yl ketone
101. CH.sub.2 =CH--CHO
acrolein
102. CH.sub.3 --CH=CH--CHO
crotonaldehyde
103. ##SPC33##
.alpha.-chloroacrolein
104. ##SPC34##
.alpha.-bromoacrolein
105. CH.sub.2 =CH--C.tbd.N
acrylonitrile
106. CH.sub.3 CH=CH--C.tbd.N
crotononitrile
107. ##SPC35##
.alpha.-chloroacrylonitrile
108. ##SPC36##
.alpha.-bromoacrylonitrile
109. ##SPC37##
.beta.-bromomethacrylonitrile
110. ##SPC38##
.beta.-chloroethacrylonitrile
111. ##SPC39##
methyl .alpha.-cyanoacrylate
112. CH.sub.2 =CH--CO--NH--CH.sub.2 --CO--NH.sub.2
acrylamidoacetamide
113. ##SPC40##
methacrylamidoacetamide
114. ##SPC41##
2-crotonamido-N-methylpropionamide
115. ##SPC42##
2-acrylamidopropionamide
116. ##SPC43##
2-methacrylamidopropionamide
117. ##SPC44##
2-(.alpha.-chloroacrylamide)-3-methylbutyramide
118. Ch.sub.2 =CH--CO--NH--CH.sub.2 --NH--CO--CH.sub.3
N-(acetamidomethyl)acrylamide
119. ##SPC45##
N-(propionamidomethyl)methacrylamide
120. ##SPC46##
N-(n-butyramidomethyl).alpha.-chloroacrylamide
121. ##SPC47##
maleic anhydride
122. HOOC--CH=CH--COOH
maleic acid
123. HOOC--CH=CH--CO--NH.sub.2
maleic acid amide
124. HOOC--CH=CH--CO--NH--CH.sub.2 CH.sub.3
N-ethylmaleic acid amide
125. CH.sub.3 --OOC--CH=CH--CO--NH--CH.sub.3
N-methyl methylmaleate amide
126. CH.sub.2 =CH--OOCH
vinyl formate
127. CH.sub.2 =CH--OOC--CH.sub.3
vinyl acetate
128. CH.sub.2 =CH--OH
vinyl alcohol (obtained by hydrolysis of copolymerized vinyl
acetate)
129. ##SPC48##
isopropenyl bromoacetate
130. CH.sub.2 =CH--OOC--C--CH.sub.3).sub.3
vinyl pivalate
131. CH.sub.2 =CH--NH--COO--C--CH.sub.3).sub.3
N-vinyl-tertiary butylcarbamate ##SPC49##
Polymerization of the indicated monomers is achieved by
conventional transition metal ion catalyst techniques.
The following non-limiting examples illustrate the preparation of
polymers within the scope of the present invention. The numerical
ratio before the word copolymer in the following examples refers to
the molar ratio of monomers forming the copolymer.
EXAMPLE I
1:5 graft copolymer of .beta.-(methacryloyloxy)ethyl
trimethylammonium methyl sulfate on polyvinyl alcohol
100 mls. of a 10 percent aqueous solution of polyvinyl alcohol
(commercially available from E. I. duPont deNemours and Company,
Wilmington, Del., under the designation Elvanol 70-05), 20.25 g. of
.beta.-(methacryloyloxy)ethyl trimethylammonium methyl sulfate
(commercially available from Alcolac Chemical Corp., Baltimore,
Md., under the designation "Sipomer Q-5") and 1.5 g. of
Ce(NH.sub.4).sub.2 (NO.sub.3).sub.6 catalyst were added to a 250
ml. three-neck round-bottom flask set up with nitrogen circulation.
The pH of the resultant solution was then adjusted to 1.5 with
HNO.sub.3 and stirred overnight with a stream of nitrogen bubbling
through the solution. The polymer was then precipitated in acetone,
collected and dried under vacuum at 45.degree. C. The yellow-white
water-soluble powder was analyzed by combustion analysis based on
nitrogen and sulfur to contain 1 part Sipomer Q-5 for every 5 parts
of polyvinyl alcohol.
EXAMPLES II - XII
The procedure of Example I was employed to produce a series of
graft copolymers of .beta.-(methacryloyloxy)ethyl trimethylammonium
methyl sulfate (monomer) as follows:
EXAMPLES II - XII
__________________________________________________________________________
Molar ratio of monomer to Quantity of Quantity Quantity polyvinyl
alcohol 10% solution of of by combustion Description Example
polyvinyl alcohol monomer Ce(NH.sub.4).sub.2 (NO.sub.3).sub.6
analysis of product
__________________________________________________________________________
II 100 mls. 20.25 g. 3.0 g. 1:7 yellow-white powder III 100 mls.
40.50 g. 1.5 g. 1:12 white powder IV 25 mls. 20.25 g. 0.19 g. 6:37
yellow powder V 100 mls. 81.00 g. 1.5 g. 5:29 light-brown powder VI
100 mls. 81.00 g. 3.0 g. 1:4 yellow-white powder VII 25 mls. 40.50
g. 0.19 g. 3:86 yellow powder VIII 25 mls. 40.50 g. 0.375 g. 4:23
white powder IX 25 mls. 40.50 g. 0.75 g. 2:7 yellow powder X 12.5
mls. 40.50 g. 0.375 g. 6:17 yellow powder XI 100 mls. 40.50 g. 3.0
g. 1:6 yellow-white powder XII 12.5 mls. 40.50 g. 0.19 g. 3:65
yellow powder
__________________________________________________________________________
EXAMPLE XIII
Graft copolymer of 3-(methacryloyloxy)-2-hydroxyprop-1-yl
trimethylammonium chloride and isopropyl acrylamide on polyvinyl
alcohol
63 g. of isopropyl acrylamide and 10 g. of
3-(methacryloyloxy)-2-hydroxyprop-1-yl trimethylammonium chloride
(commercially available from the aforementioned Alcolac Chemical
Corporation under the designation Sipomer Q-1) were added with
stirring to a solution of 11 g. of polyvinyl alcohol in 500 cc. of
water at 50.degree. C. and under nitrogen. Nitrogen was bubbled
through the solution for 1 hour, the pH adjusted to 1.5 with
HNO.sub.3 and then 1.1 g. of Ce(NH.sub.4).sub.2 (NO.sub.3).sub.6
catalyst in 10 cc. of water was added. Stirring of the solution was
continued for 2 hours and the resultant viscous liquid was diluted
with 250 cc. of water. The liquid product was analyzed to have 9.3
percent solids and a residual isopropyl acrylamide content of 0.1
g./l.
The following general procedure may be used for preparing
photographic emulsions using the above-described polymeric salts of
the instant invention as the colloid binders.
A water-soluble silver salt, such as silver nitrate, may be reacted
with at least one water-soluble halide, such as potassium, sodium,
or ammonium bromide, preferably together with potassium, sodium or
ammonium iodide, in an aqueous solution of the polymer. The
emulsion of silver halide thus-formed contains water-soluble salts,
as a by-product of the double decomposition reaction, in addition
to any unreacted excess of the initial salts. To remove these
soluble materials, the emulsion may be centrifuged and washed with
distilled water to a low conductance. The emulsion may then be
redispersed in distilled water. To an aliquot of this emulsion may
be added a known quantity of a solution of bodying or thickening
polymer, such as polyvinyl alcohol having an average molecular
weight of about 100,000 (commercially available from E. I. duPont
deNemours & Company, Wilmington, Del., designated Type 72-60).
A surfactant, such as dioctyl ester of sodium sulfosuccinic acid,
designated Aerosol OT, (commercially available from American
Cyanamid Company, New York, N.Y.), may be added and the emulsion
coated onto a film base of cellulose triacetate sheet having a
coating of hardened gelatin.
The emulsions may be chemically sensitized with sulfur compounds
such as sodium thiosulfate or thiosulfate or thiourea, with
reducing substances such as stannous chloride; with salts of noble
metals such as gold, rhodium and platinum; with amines and
polyamines; with quaternary ammonium compounds such as
alkyl-.alpha.-picolinium bromide; and with polyethylene glycols and
derivatives thereof.
The polymers employed as the binders in the emulsions of the
present invention may be cross-linked according to conventional
procedures. As an example, the polymers may be ionically
cross-linked with a dibasic acid or cross-linked with
succinaldehyde. Cross-linking agents conventionally employed with
hydroxyl-containing polymers, such as boric acid, may also be
employed.
The emulsions of the present invention may also be optically
sensitized with cyanine and merocyanine dyes. Where desired,
suitable antifoggants, toners, restrainers, developers,
accelerators, preservatives, coating aids, plasticizers, hardeners
and/or stabilizers may be included in the composition of the
emulsion.
The emulsions of this invention may be coated and processed
according to conventional procedures of the art. They may be
coated, for example, onto various types of rigid or flexible
supports, such as glass, paper, metal, and polymeric films of both
the synthetic type and those derived from naturally occurring
products. As examples of specific materials which may serve as
supports, mention may be made of paper, aluminum, polymethacrylic
acid, methyl and ethyl esters, vinylchloride polymers, polyvinyl
acetal, polyamides such as nylon, polyesters such as polymeric film
derived from ethylene glycol-terephthalic acid, and cellulose
derivatives such as cellulose acetate, triacetate, nitrate,
propionate, butyrate, acetate propionate, and acetate butyrate.
Suitable subcoats may be provided on the supports, for example, a
layer of gelatin, if necessary or desirable for adherence, as is
well known in the art.
The polymers employed in the practice of the instant invention may
contain about 5 to 75 mole percent of the grafted monomer,
preferably about 20 mole percent. The specific amount employed may
be selected by the operator depending upon the grain particle size
and habit desired. For example, the grain size distribution of the
emulsion may be varied by changing the mole ratio and type of
monomer grafted on the hydroxyl-containing polymer backbone.
By selecting appropriate comonomers, the copolymers of this
invention may be made to be compatible with all water-soluble
bodying polymers. Emulsions made from these novel polymers may be
bodied with any water-soluble polymers, overcoming the disadvantage
encountered with gelatin which is only compatible with a very few
polymers in a most limited pH range. As examples of specific
materials which may serve as bodying polymers are gelatin,
polyvinyl alcohol, polyacrylamide, polyalkylacrylamides, polyvinyl
pyrrolidone, polymethacrylamidoacetamide, vinyl
alcohol/N-vinylpyrrolidone copolymers, poly-N-ethylaziridine,
poly-N-(2-hydroxyethyl) aziridine, poly-N-(2-cyanoethyl) aziridine,
poly (.beta.-hydroxy-ethyl acrylate), polyethylene imine and
cellulose derivitives such as hydroxyethyl cellulose, hydroxypropyl
cellulose and methyl cellulose. It has been found that using only a
small amount of one or more of the graft copolymers, large amounts
of photosensitive silver halide grains may be obtained. An emulsion
made from one of the graft copolymers may therefore be bodied with
a water-soluble polymer such that the polymeric constitution of the
resulting emulsion comprises a relatively large percentage of the
bodying polymer.
By selecting appropriate comonomers, copolymers with selected
diffusion characteristics may be prepared. For example, the rate of
diffusion of alkali ion or a dye-developer through an emulsion
comprising one of the polymers of this invention may be modified by
varying the composition of the polymer.
The preparation and photographic utilization of the instant
invention will be further illustrated by reference to the following
non-limiting examples.
EXAMPLE XIV
Silver halide emulsions employing the polymers of Examples I-X as
colloid binders were prepared by the following procedure.
A solution of 4.15 g. of the dry graft polymer in 266 ml. of
distilled water was adjusted to pH 3.0 with dilute nitric acid and
maintained at a temperature of 55.degree. C. To this solution, 88.0
g. of dry potassium bromide and 1.0 g. of dry potassium iodide were
added.
A solution of 55 g. of silver nitrate in 500 ml. of distilled water
was prepared. From this silver nitrate solution, 100 ml. was
rapidly added with continuous agitation to the polymer-halide
solution and the remainder was added over a period of 22 minutes.
Thereafter, the emulsion was ripened for 60 minutes at 55.degree.
C., and then rapidly cooled to below 20.degree. C.
EXAMPLE XV
Silver halide emulsions employing the polymers of Examples XI and
XII as the colloid binders were prepared by the procedure of
Example XIV, except that the quantities of all reagents were
one-half those of Example XIV when the polymer of Example XI was
used and one-quarter those of Example XIV when the polymer of
Example XII was used.
EXAMPLE XVI
A sliver halide emulsion employing the polymer of Example XIII as
the colloid binder was prepared by the following procedure.
A solution comprising 43.62 g. of the liquid graft copolymer (at
9.3 percent solids) in 266 ml. of distilled water was adjusted to
pH 6.5 with dilute nitric acid and maintained at a temperature of
28.degree. C. To this solution, 44.0 g. of dry potassium bromide
and 0.50 g. of dry potassium iodide were added.
A solution of 55 g. of silver nitrate in 500 ml. of distilled water
was prepared. From this silver nitrate solution, 100 ml. was
rapidly added to the polymer-halide solution and the remainder was
added over a period of 22 minutes. Thereafter, the emulsion was
ripened for 30 minutes at 28.degree. C., with continuous agitation,
at the end of which it was rapidly cooled to below 20.degree.
C.
EXAMPLE XVII (control)
A silver halide emulsion employing gelatin as the colloid binder
was prepared according to the procedure of Example XVI, except that
4.15 g. of dry gelatin was added to the 266 mls. of distilled water
and the emulsion was ripened at a temperature of 55.degree. C.
The following table summarizes the silver halide grain sizes
obtained in the emulsions prepared above. All emulsions contained
octahedral platelet crystals.
TABLE 1
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Grain Size (microns) Examples Polymer Range Average
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I and XIV 1:5 graft copolymer of .beta.-(methacryloyloxy) ethyl
trimethylammonium methyl sulfate on polyvinyl alcohol 0.2-0.8 0.4
II and XIV 1:7 graft copolymer of the above materials 0.2-1.4 0.6
III and XIV 1:12 graft copolymer of the above materials 0.3-1.2 0.5
IV and XIV 6:37 graft copolymer of the above materials 0.3-1.6 0.6
V and XIV 5:29 graft copolymer of the above materials 0.2-1.7 0.7
VI and XIV 1:4 graft copolymer of the above materials 0.3-1.6 0.7
VII and XIV 3:86 graft copolymer of the above materials 0.3-2.4 0.6
VIII and XIV 4:23 graft copolymer of the above materials 0.3-1.3
0.6 IX and XIV 2:7 graft copolymer of the above materials 0.2-1.2
0.4 X and XIV 6:17 graft copolymer of the above materials 0.4-1.2
0.6 XI and XV 1:6 graft copolymer of the above materials 0.2-1.0
0.5 XII and XV 3:65 graft copolymer of the above materials 0.4-1.2
0.5 XIII and XVI 13:1:5.9 graft copolymer of N-isopropyl acrylamide
and 3-(methacryloyloxy)-2-hydroxyprop-1-yl trimethylammonium
chloride on polyvinyl alcohol -- 0.4 XVII gelatin 0.2-1.8 1.0
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EXAMPLE XVIII
The emulsion mixture of Example V was centrifuged and washed with
water to a low conductance and then redispersed in distilled water.
To some aliquots of this emulsion were added solutions of bodying
or thickening polymer of polyvinyl alcohol having an average
molecular weight of about 100,000 (commercially available from E.
I. duPont deNemours & Company; Wilmington, Del., designated
Type 72-60) at a silver to polymer ratio of about 1:0.74. The
remaining aliquots received no bodying polymer solution. A
surfactant, Aerosol OT, was added and each emulsion aliquot was
slot coated at various silver coverages onto a base of cellulose
triacetate sheet 5 mils thick subcoated with 30 mg/sq. ft. of
hardened gelatin. This film so prepared was air dried, exposed on a
sensitometer, and processed with a processing solution and an
image-receiving sheet from a Polaroid Type 107 Land film assembly
(Polaroid Corporation, Cambridge, Mass.). The negative and
image-receiving elements were maintained in superposed position for
10 seconds after which they were stripped apart. Alternatively, the
processing was effected with a processing solution and an
image-receiving element from a Polaroid Type 42 Land film. The
photographic characteristics of the resulting positive prints were
then measured by an automatic recording densitometer. The following
table summarizes the densitometer readings obtained on samples of
these prints:
TABLE 2
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Ag/Bodying Grain-growing Bodying Polymer mg/Ag Film Polymer Polymer
Ratio ft..sup.2 System D.sub.max D.sub.min .DELTA.D
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13:1:5.9 graft copolymer none .infin. 71.3 T-42 1.76 0.03 1.73 of
N-isopropyl acrylamide and 3-(methacryloyloxy)-2- hydroxyprop-1-yl
trimethyl- ammonium chloride do. do. do. do. T-107 1.73 0.01 1.72
do. polyvinyl 1:0.74 67.8 T-42 1.71 0.39 1.32 alcohol No. 72-06 do.
do. do. do. T-107 1.76 0.11 1.65
__________________________________________________________________________
In certain photographic applications, it may be desirable to
replace part, but not all, of the gelatin in the photosensitive
emulsion. In view of the characteristics of these polymers
described above, and further, in view of their compatability with
gelatin in substantially all proportions, it will be obvious that
these polymers are ideally suited for such use.
The term "photosensitive" and other terms of similar import are
herein employed in the generic sense to describe materials
possessing physical and chemical properties which enable them to
form usable images when photo-exposed by radiation actinic to
silver halide.
Since certain changes may be made in the above products and
processes without departing from the scope of the invention herein
involved, it is intended that all matter contained in the above
description shall be interpreted as illustrative only and not in a
limiting sense.
* * * * *