US 3317344 A
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. 3,317,344 ANTISTATIC PHOTOGRAPHIC FILM E. Scudder Mackey and Harvey Abend, Bingllamton,
N.Y., assignors to General Aniline & Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Sept. 27, 1963, Ser. No. 311,981 6 Claims. (Cl. 117-121) This invention relates to photographic film and particularly to a photographic film having antistatic properties.
It is well established that photographic films have a strong tendency to acquire and accumulate static electricity. Such static electrification can occur during the manufacture of the film base; during subsequent emulsion coating, trimming and packaging operations; or by operation in cameras, particularly in motion picture cameras and cameras used for X-ray fiuorography where a series of pictures is taken in rapid succession. The sudden discharge of these static charges, after a light-sensitive emulsion coating has been applied to the film base, causes typical static markings in the photographic emulsion and these become visible upon development. Static marks are especially troublesome in films which must be manufactured without an antihalation backing layer and are, therefore, deprived of the antistatic protection normally provided by such layers during the manufacturing operation. Considerable static electricity is generated and eventually given off in the form of spark discharges when such a fihn without an antihalation layer or other antistatic protection is Wound into a tight roll and subsequently unwound, for instance, during coating or While being unwound in a camera magazine. The results of these spark discharges show up in the developed film as black spots, streaks, lines, irregular fogged patterns,
or combinations thereof.
Static charges also manifest their disagreeable nature in finished film and cause, for example, an increase in the friction in the film against the gates of a projector or other parts thereof through which the film passes.
It has been attempted to overcome the generation of static in films by applying conducting or hygroscopic substances to the surface of the film with the intent to impart conductivity to the film and to dissipate the static electricity before discharge and spot exposure of the emulsion.
Generally, such substances are laid down in a hydrophilic colloid coating which serves as an antihalation and/ or an anticurl backing layer. It is essential in these applications that the antistatic composition be such that it does not reduce the adhesion of the antihalation or anticurl layer for the base, since otherwise such layer will peel away from the base. This phenomenon which is often encountered is referred to as dry peel. A further prerequisite is that the antistatic composition must not contribute to foam produced in processing solutions, particularly in those solutions agitated with gas bursts. A
further objective is that the antistatic composition must cause no undesirable physical appearance such as matte, streaks or repellers in the coating. Finally, the composition must not react with the light-sensitive emuls1on to impart what is defined as photo activity.
We have now discovered that photographic film can be protected against static susceptibility by incorporating into a conventional antihalo or NC layer, a mixture of a phosphate ester of a polyalkylene oxide derivative of an alkyl phenol and a quaternary ammonium salt contammg one quaternary ammonium nitrogen atom, a nitrate radical and two hydroalkyl or hydroxyaryl radicals wherein the hydroxy group is in the terminal position.
The conjoint use of the phosphate ester and the quaternary ammonium salt produces a composition which has the ability to become molecularly oriented with the surface of the base in such a way that it not only provides the base with a conductive surface, but provides a means of reducing static by forming a film which aifords some dielectric shielding.
Coatings of a hydrophilic colloid containing the aforesaid mixture for antistatic purposes constitute the purposes and objects of the present invention.
The phosphate esters of the alkyl phenols which are employed are Well known and can broadly be defined as the reaction product of one mole of P 0 with from 2.0 to 4.5 moles of a non-ionic surface-active agent, derived from an alkyl phenolic compound under substantially anhydrous conditions and at a temperature below 110 C. Numerous compounds of this type, i.e., polyalkylene oxide derivatives of phenolic compounds containing one or more alkyl substituents are described in U.S. Patents 2,213,477 and 2,593,112. Those preferred are the polyalkylene oxide derivatives of alkyl phenolic compounds in which the total number of alkyl carbon atoms is between 4 and 20. Such phenolic compounds may be exemplified by normal and isomeric butyl, amyl, dibutyl, and diamyl phenols and cresols, tripropyl phenols and cresols, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, cetyl, oleyl, octadecyl and the like, phenols and cresols in addition to dihexyland trihexyl-phenol prepared from 'hexene-l and phenol, diisoheptyl-phenol, dioctyl-phenol,
dinonyl-phenol, dioctyl-p-cresol, dioctyl-o-cresol, didecylphenol, didecyl-p-cresol, didodecyl-phenol, and the like. Of particular value are the polyalkylene oxide derivatives of secondary and tertiary alkyl substituted phenols and cresols obtained by condensing olefins of the type obtained in petroleum refining with phenols or cresols. In the case of products obtained by condensing phenol or cresol with olefins of from 3 to 5 carbon atoms such as propylene, butylene or amylene, it is sometimes desirable to employ the dialkylated phenols or cresols, while in the case of compounds obtained by condensing a phenol or cresol with an olefin containing 8 or more carbon atoms, the mono-substituted derivatives are sometimes preferred. Particularly desirable derivatives can be obtained from the phenols and cresols containing a substituent derived from olefins containing from 8 to 18 carbon atoms, such as diisobutylene and other alkylenes as nonylene, decylene, alndecylene, dodecylene, pentadecylene, octadecylene and mixtures thereof, and may advantageously be the dimers and trimers obtained by polymerization of such low molecular weight olefins as propylene, butylene, isobutylene, amylene or mixtures thereof.
These non-ionic surface-active agents are also well known in the art and, in general, they are prepared by condensing a polyglycol ether containing the required number of alkenoxy groups or alkylene oxide such as propylene oxide, blutylene oxide or preferably ethylene oxide with the above-described alkylphenol compounds. The amount of alkylene oxide or equivalent condensed with the alkylphenolics, i.e., the length of the polyoxyalkylene chain, can vary over extremely wide range but as a convenient rule, of thumban amount of alkylene oxide or equivalent should be employed which will result in a condensation product containing about 20 to by weight of combined alkylene oxide.
The following is an illustrative, non-limitative list of some specific examples of suitable non-ionic surface active agents which may be employed. In this list, E.O. means ethylene oxide and the number preceding same refers to the number of moles thereof reacted with one mole of the given reactive hydrogen-containing compound.
Heptylphenol+7 E.O. Diamylphenol+ 12 BO. Nonyl+9l1 E.O. Nonylphenol+2 E.O. Dinonylphenol+7 E.O. Dodecylphenol+ 18 B0.
In carrying out the phosphation reaction, the P is preferably added gradually, with vigorous agitation, to the non-ionic surface-active agent in liquid form. If the latter agent is a solid at room temperature, it should be heated to above its melting point. Addition of the nonionic surface-active agent to the P 0 is inadvisable since this has been found to result in the formation of tar and the like and to prevent the reaction from proceeding to completion. The reaction is exothermic and in some cases cooling is necessary to prevent the temperature from going above about 110 0., since this tends to produce discolored and darkened products. The reaction proceeds continuously during addition of the P 0 and solution thereof in the non-ionic surface-active agent, and is substantially 90% complete or more by the time all of the P 0 has been added. The few particles of solid P 0 remaining in the reaction medium may be removed at this point if time is of the essence, but it is preferred in the interests of economy to allow the reaction to proceed for an additional period of time which may range from /2 to 5 hours or more at ambient temperatures up to about 110 C. until all of the P 0 has dissolved indicating complete reaction between the reactants involved. Vigorous agitation during the reaction is highly desirable to facilitate and expedite completion of the reaction.
The phosphate esters employed may be supplied in free unneutralized form or in the form of the partially or completely substituted salts containing as cations alkali metals, alkaline earth metals, metals, ammonium and organic amines. It is to be understood that such salts are to be regarded as the equivalent of the present products in their free form. As examples of suitable cations, there may be mentioned sodium, potassium, lithium, calcium, strontium, barium, magnesium, iron, tin, cadmium, aluminum, antimony, chromium, manganese, mercury, nickel, silver, zinc, ammonium and aliphatic, alicyclic, aromatic and heterocyclic organic amines such as the mono-, di-, and tri-methylamines, ethylamine, propylamines, laurylamines, stearylarnines, ethanolamines, propanolamines, butanolamines, hexanolamines, cyclohexylamines, phenylamines, pyridylamines, morpholinylamines, and the like.
The quaternary ammonium compounds which are admixed with the above-described phosphate esters correspond to the general formula:
wherein each of R and R represent an alkyl radical of from 1 to 20 carbon atoms, one of R or R having preferably more than 5 carbon atoms, and each of X and Y represent divalent radicals selected from the group consisting of phenylene radicals and alkylene radicals of from 2 to 20 carbon atoms.
The following is an illustrative non-limitative list of some specific examples of suitable quaternary ammonium compounds which may be employed to prepare the antistatic compositions in accordance with the teachings of this invention.
The process of this invention is carried out simply by incorporating at least one quaternary ammonium compound and at least one phosphate ester into an aqueous solution containing an appropriate amount of a hydrophilic colloid such as gelatin, along with conventional hardeners and coating aids and coating the solution on film base. The relative amounts of phosphate ester and quaternary ammonium compounds are not narrowly critical, and for each part by weight of the phosphate ester employed from 0.5 to 8.0 parts of quaternary ammonium compound can be used. Additionally, the relative amount of antistatic agent which is. incorporated into the colloidal antihalo or NC layer may vary from 3 to 15% based on the dry weight of the colloidal carrier in such layer.
It is to be emphasized that the results contemplated herein can only be achieved by the concomitant use of the phosphate ester and the quaternary ammonium salt. Thus, if the phosphate ester is used alone and in such concentration as to produce conductivity, gross dry peel of the layer containing the ester ensues. If the concentration be lowered so that only marginal dry peel is evinced, the phosphate ester produces excessive foam in the processing solutions. Moreover, certain gels, in combination with conductive concentrations of the phosphate ester, coat out with a matte-like appearance considered undesirable for certain applications.
On the other hand, if the quaternary ammonium salt alone is employed in concentrations to provide conductivity, there is produced a repellent and oily coating which has a tendency to produce an undesirable efiiect in the emulsion. The latter can be reduced by lowering the concentration, but as a consequence the conductivity is likewise reduced to an ineffective level.
However, by combining in a hydrophilic colloid layer low levels of concentration of the phosphate ester and quaternary ammonium salt, a synergistic effect is realized. This synergistic effect will be more clearly spelled out in the examples wherein comparisons between the two-component compositions are made with the one-component compositions.
The following examples will illustrate the best mode contemplated for carrying out the invention, but it is to be understood that it is not intended to be limited thereto.
Example I To an aqueous solution containing 1 kilogram of gelatin and conventional coating finals, including saponin (coating aid) and mucochloric acid (hardener), is added:
(a) 18 grams of a phosphate ester prepared by reacting nonylphenol with 6 moles of ethylene oxide to obtain a surface-active agent and then reacting 2.7 moles of said surface-active agent with one mole of phosphorous pentoxide.
(b) 25 grams of a quaternary ammonium salt corresponding to the formula:
cellulose or the like.
The above emulsion is then coated on a cellulose acetate film strip to yield a film having excellent antistatic properties, as well as excellent physical properties, in that the emulsion layer did not peel away from the base and did not contribute to foam when processed.
A coating on cellulosic acetate was prepared as above with the exception that the quaternary ammonium salt was omitted. This coating had 50% less conductivity and produced over twice the foam level in processing as that of Example I.
Another coating on cellulosic acetate was prepared as in Example I while omitting the quaternary ammonium salt and while using 90 grams of the phosphate ester. This coating had a conductivity similar to that of Exam le I, but produced an undesirable foam level in the developer solution and was subject to dry peel.
Another coating was prepared as in Example I using the same amount of the quaternary ammonium salt but while eliminating the phosphate ester. This coating had 33% 'less conductivity and over twice the foam level of the coating of Example I.
Finally, a coating was made according to Example I while utilizing only the quarternary ammonium salt and while employing 35 grams of the same. The conductivity was good but the coating showed a repellent coating quality and evidence of photo activity.
Example 11 The procedure of Example I is repeated with the exception that the quaternary ammonium compound corresponds to the formula:
(CHa)2-'=NNOa I Hg-OH Excellent results in both antistatic properties and physical properties are also obtained in this example.
Example III The procedure of Example I is repeated with the exception that the quaternary ammonium salt corresponds to the formula:
In like manner, excellent results are obtained by the procedure of this example.
Example IV The procedure is the same as in Example I excepting that the quaternary ammonium compound corresponds to the formula:
H50: CgHt-OH N-NOa 200; (52114-015:
while the present invention has been described with reference to certain preferred procedures, it is to be understood that the invention is not limited thereto, that variations may be made in the procedures described therein and that the equivalent materials may be substituted without departing from the scope of the invention. Thus, in place of gelatin, other hydrophilic colloids may be used such as polyvinyl alcohol, casein, polyvinylpyrrolidone, methyl In place of the cellulose acetate 6 film base other film supports such as polystyrene, polymethyleneterephthalate or polycarbonate can be employed.
It will be understood, therefore, that it is not intended that this invention be limited except as necessitated by the appended claims.
What is claimed is:
1. A photographic element comprising a film support coated with a layer of a hydrophobic colloid containing an antistatic mixture of (a) a phosphate ester prepared by reacting one mole of P 0 with 2.2 to 4.5 moles of a non-ionic surface-active agent having the molecular configuration of a condensation product of at least one mole of ethylene oxide with one mole of an alkyl phenol under substantially anhydrous conditions at a temperature below about C. and (b) a quaternary ammonium compound corresponding to the formula:
I I-N 0a R Y wherein each of R and R represent an alkyl radical of from 1 to 20 carbon atoms and each of X and Y represent divalent radicals selected from the group consisting of phenylene radicals and alkylene radicals of from 2 to 20 carbon atoms.
2. The article of claim 1 wherein one of R and R contains at least 5 carbon atoms.
3. The article of claim 1 wherein the alkyl phenol is nonyl phenol.
4. The article of claim 2 wherein the quaternary ammonium compound corresponds to the formula:
5. The article of claim 2 wherein the quaternary ammonium compound corresponds to the formula:
6. The article of claim 1 wherein R contains less than 5 carbon atoms and R contains at least 5 carbon atoms.
References Cited by the Examiner UNITED STATES PATENTS 2,213,477 9/1940 Steindorif et al 260-613 2,240,469 4/1941 Swan et a1.
2,368,287 1/1945 Chilton 11734 2,461,478 2/1949 Kaszuba 1l7--144 X 2,527,260 10/1950 Hart et a1 117-34 X 2,593,112 4/1952 Cross et al. 260613 2,982,651 5/1961 Mackey 117-34 X 3,018,178 1/1962 Harriman 117-34 X 3,039,870 6/1962 Laakoo et a1 11734 X 3,206,312 9/1965 Sterman et al. 117-144 X WILLIAM D. MARTIN, Primary Examiner.
T. G. DAVIS, Assistant Examiner.