Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Identified radiation sensitive composition with color...
Reexamination Certificate
2001-06-14
2003-06-10
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Identified radiation sensitive composition with color...
C430S539000, C430S631000, C430S642000, C430S643000, C430S637000
Reexamination Certificate
active
06576412
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a hydrophilic colloid composition e.g. a composition for the coating of a layer in a photographic element.
BACKGROUND OF THE INVENTION
Photographic coating compositions containing aqueous gelatin and high levels of anionic surfactants are prone to exhibit high viscosity, either as simple melts or as more complex melts such as dispersions of relatively hydrophobic materials (e.g. oil) where the anionic surfactant is used as the dispersing aid. In the simple melt case, rheological properties tend to be Newtonian in behaviour. In the disperse system case, systems can be strongly non-Newtonian, exhibiting high viscosity at low shear and low viscosity at high shear. Such properties can adversely affect the transport and coating uniformity of these systems.
The addition of certain cationic or nonionic surfactants to these systems is known to reduce their viscosity and shear thinning behaviour, and can therefore be used to overcome problems of this kind. For example, U.S. Pat. No. 5,300,418 describes the use of specific nonionic surfactants for reducing the viscosity of photographic dispersions. GB-A-2 140 572 describes the use of specific cationic surfactants for reducing the viscosity of photographic dispersions.
Problem to be Solved by the Invention
There is a need for rheology modifiers in the above-mentioned compositions which are much more efficient at reducing low shear viscosity and shear thinning behaviour.
SUMMARY OF THE INVENTION
The invention provides a hydrophilic colloid composition having hydrophobic material dispersed therein and comprising an anionic surface active agent characterised in that the composition further comprises a cationic surface active agent in an amount sufficient to reduce the viscosity of the composition, the cationic surface active agent comprising a hydrophobic moiety, a non-ionic hydrophilic moiety and a cationic hydrophilic moiety.
Advantageous Effect of the Invention
Cationic surfactants containing polyethoxylate groups offer advantages over either cationic or nonionic surfactants as rheology modifiers in the above-mentioned compositions. In the simple melt case, they are more efficient at reducing viscosity than either the nonionic or cationic surfactants, and show better compatibility with the anionic surfactants than basic cationic surfactants insofar as they provide clear solutions as opposed to cloudy or phase-separating systems. In the case of disperse systems, they are much more efficient at reducing low shear viscosity and shear thinning behaviour.
DETAILED DESCRIPTION OF THE INVENTION
The cationic surface active agent used in the composition of the invention as a rheology modifier comprises a hydrophobic moiety, a nonionic hydrophilic moiety and a cationic hydrophilic moiety.
The cationic hydrophilic moiety is preferably a quaternised nitrogen (N
+
) to which the other moieties are covalently bound.
The nonionic hydrophilic moiety is preferably one or two polyethoxylate groups.
The hydrophobic moiety is preferably a hydrocarbon group.
Preferred cationic surface active agents include compounds having the structure
wherein
R
1
is an alkyl, alkenyl, alkylaryl or arylalkyl chain having from 8 to 20 carbon atoms or a partially or fully fluorinated alkyl, alkenyl, alkylaryl or arylalkyl chain of equivalent hydrophobic strength e.g. having from 4-14 carbon atoms;
R
2
is hydrogen, alkyl having from 1 to 8 carbon atoms e.g. methyl and n-butyl, or benzyl;
R
3
is hydrogen or alkyl having from 1 to 4 carbon atoms e.g. methyl (preferably R
3
is hydrogen if the sum of n and m is greater than 0;
X
−
is halide (preferably Br
−
or Cl
−
);
L represents a suitable linking chemistry between R
1
and the positively charged nitrogen e.g. a covalent chemical bond or —(CH
2
CH
2
O)
x
—;
each m and n independently is 0 or an integer such that m+n is 2 to 30, preferably 5 to 30, more preferably 12 to 18 and most preferably 15; and,
X is an integer from 2 to 30, preferably 5 to 30, more preferably 12 to 18 and most preferably 15.
For preferred structures, L is —(CH
2
CH
2
O)
x
— when m+n is 0, and each m and n independently is greater than 0 when L is other than —(CH
2
CH
2
O)
x
—. Preferred compounds include those wherein
R
1
is an alkyl or alkylaryl group having from 10 to 20 carbon atoms;
R
2
is alkyl having from 1 to 4 carbon atoms e.g. methyl and n-butyl;
R
3
is hydrogen;
L represents a covalent chemical bond; and, m+n is 5 to 30, preferably 15.
Other preferred compounds include those wherein
R
1
is an alkyl or alkylaryl group having from 10 to 20 carbon atoms;
R
2
is alkyl having from 1 to 8, preferably 1 to 4 carbon atoms e.g. methyl and n-butyl;
R
3
is alkyl having from 1 to 4 carbon atoms e.g. methyl;
each m and n independently is 0;
L represents —(CH
2
CH
2
O)
x
—;
x is an integer from 5 to 30, preferably 15.
Preferably, the cationic surface active agent is present in the composition in an amount from 0.1 to 0.5, more preferably from 0.2 to 0.4 equivalents relative to the amount of anionic surfactant present in the system.
A preferred hydrophilic colloid is gelatin e.g. alkali-treated gelatin (cattle bone or hide gelatin) and acid-treated gelatin (pigskin or cattle gelatin) or a gelatin derivative e.g. acetylated gelatin and phthalated gelatin. Other suitable hydrophilic colloids include naturally occurring substances such as proteins, protein derivatives, cellulose derivatives e.g. cellulose esters, polysaccharides e.g. dextran, gum arabic, zein, casein and pectin, collagen derivatives, agar-agar, arrowroot and albumin. Examples of suitable synthetic hydrophilic colloids include polyvinyl alcohol, acrylamide polymers, maleic acid copolymers, acrylic acid copolymers, methacrylic acid copolymers and polyalkylene oxides.
The hydrophobic material dispersed in the hydrophilic colloid composition may be any hydrophobic photographic addenda.
A number of hydrophobic photographic additives used in light sensitive photographic materials are oil-soluble and are used by dissolving them in a substantially water-insoluble, high boiling point solvent which is then dispersed in an aqueous hydrophilic colloid solution with the assistance of a dispersing aid. Such oil-soluble additives include image forming dye couplers, dye stabilizers, antioxidants and ultra-violet radiation absorbing agents. A typical solvent used to dissolve the additive is aromatic e.g. di-n-butyl phthalate.
In the following discussion of suitable materials for use in the compositions and materials of this invention, reference will be made to
Research Disclosure
, December, 1989, Item 308119, published by Kenneth Mason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire, P010 7DQ, UK. This publication will be identified hereafter by the term
Research Disclosure.
Suitable methods of preparing photographic dispersions are described in
Research Disclosure
, Sections XIV A and XIV B. For example, homogenised oil in aqueous gelatin dispersions of photographic couplers can be prepared by dissolving the coupler in a coupler solvent and mechanically dispersing the resulting solution in an aqueous gelatin solution (see U.S. Pat. No. 2,322,027).
Alternatively, microprecipitated dispersions of photographic couplers prepared by solvent and/or pH shift techniques are becoming more widely used (see references: U.K. Patent No. 1,193,349; Research Disclosure 16468, December 1977 pp 75-80; U.S. Ser. No. 288,922 (1988) by K. Chari; U.S. Pat. Nos. 4,970,139 & 5,089,380 by P. Bagchi; U.S. Pat. No. 5,008,179 by K. Chari, W. A. Bowman & B. Thomas; U.S. Pat. No. 5,104,776 by P. Bagchi & S. J. Sargeant) and offer benefits in decreased droplet size and often increased reactivity relative to conventional oil-in-water homogenised dispersions.
Couplers which form cyan dyes upon reaction with oxidized color-developing agents are described in such representative patents and publications as U.S. Pat. Nos. 2,772,162; 2,895,826; 3,002,836; 3,034,892; 2,747,293; 2,423,730; 2,367,531; 3,041,236; and 4
Howe Andrew
Miller David D.
Pitt Alan R.
Eastman Kodak Company
Letscher Geraldine
Wells Doreen M.
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