US 3887377 A
An antistatic photographic light-sensitive material having thereon a surface layer comprising the antistatic compound represented by the following general formula; WHEREIN R and R', which may be the same or different, each represents an aliphatic hydrocarbon residue having 1-22 carbon atoms, the sum of carbon atoms of R and R' being 6-40, A represents a divalent aliphatic hydrocarbon residue having 4-8 carbon atoms in total, M represents a hydrogen atom, a metal atom or a quaternary ammonium salt, and m represents a number corresponding to the valence of M.
Description (OCR text may contain errors)
United States Patent [1 1 Yamamoto et al.
[ ANTISTATIC PHOTOGRAPHIC LIGHT-SENSITIVE MATERIALS  Inventors: Nobuo Yamamoto; Masakazu Yoneyama; Wataru Ueno; Takayuki Inayama, all of Kanagawa, Japan  Assignee: Fuji Photo Film Co., Ltd.,
Kanagawa, Japan  Filed: July 19, 1973  Appl. No.: 380,795
 Foreign Application Priority Data July 22, 1972 Japan 47-73542 Oct. 24, 1972 Japan ..47-1O6487 p  US. Cl 96/87 A; 96/50 PL; 96/67; 96/114', 96/114.2', 96/114.5  Int. Cl G036 1/82  Field of Search 96/87 A, 50 PL, 114.2,
 References Cited UNITED STATES PATENTS 3,415,649 12/1968 Nishio et a1 96/1 14.5 3,525,620 8/1970 Nishio et a1 96/84 A 3,756,828 9/1973 Masakazu Yoneyama 96/87 A June 3, 1975 Primary ExaminerNorman G. Torchin Assistant ExaminerAlfonso T. Suro Pico Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn and Macpeak [5 7] ABSTRACT An antistatic photographic light-sensitive material having thereon a surface layer comprising the antistatic compound represented by the following general formula;
R O-A-SO3 M 11 Claims, No Drawings 1 ANTISTATIC PHOTOGRAPHIC LIGHT-SENSITIVE MATERIALS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rendering a photographic light-sensitive material antistatic, and, more particularly, it relates to an antistatic photographic light-sensitive material comprising at least one light-sensitive silver halide emulsion layer and at least one non-gelatin containing antistatic backing layer.
2. Description of the Prior Art In general, photographic light-sensitive materials comprise a support having provided on one or both surfaces thereof a light-sensitive photographic emulsion layer via a subbing layer capable of strongly adhering the support to the photographic emulsion layer.
The support typically comprises a film of a poly-ozolefin (e.g., polyethylene, polystyrene, etc. a cellulose ester (e.g., cellulose triacetate), a polyester (e.g., polyethylene terephthalate etc.), paper, synthetic paper, or a sheet laminated on both sides with a poly-a-olefin or like synthetic resin.
As photographic light-sensitive materials having an emulsion layer coated on both sides of a support, there can be illustrated, e.g., an X-ray film for direct use. In most other photographic light-sensitive materials, however, a photographic emulsion is coated only on the one side of the support. Therefore, in the latter case, the photographic materials possess a photographic emulsion-free surface, i.e., the surface of a support itself, which surface is usually called the back surface of the photographic light-sensitive material.
Since photographic light-sensitive materials comprise, as is described above, an insulating support and a photographic layer, electrostatic charges tend to accumulate during the steps of producing the photographic light-sensitive materials and upon the use thereof due to contact friction with the surface of the same or different substances, or due to delamination. These accumulated electrostatic charges cause a number of problems. For example, in photographic films which have not been developed the light-sensitive emulsion layer will be sensitized by the discharge of the accumulated electrostatic charges, which results in the formation of dot-like spots or branched or feather-like line marks upon development. These are commonly called static marks, and seriously or, in some cases, completely, spoil the commercial value of the photographic films. For example, it can easily be imagined that in the case of X-ray films for medical or industrial use static marks would lead to serious difficulties. Since this phenomenon becomes clear only after development, it constitutes a serious problem. In addition, the accumulated electrostatic charge can cause adhesion of surrounding dust onto the surface of the films, which leads to secondary problems such as non-uniformity trouble in coating.
As stated, such electrostatic charges often accumulate during production and use of the photographic light-sensitive materials. For example, in the production of photographic materials electrostatic charge is generated by contact friction between the photographic film and a roller as by the separation of the support surface from an opposing emulsion-coated surface in winding and unwinding steps. Also, with respect to the finished products, electrostatic charge is generated by delamination of the base surface form the emulsioncoated surface in winding and unwinding steps under sufficient humidity to cause adhesion of the photographic films to each other, by contact friction of movie films with mechanical portions of a camera and during the delamination of the base surface from the emulsion surface upon photographing and changing movie films, or by the contact and separation of X-ray film and mechanical portions in an automatic camera for X-ray films or fluorescent-sensitizing paper. In addition, electrostatic charge is also generated due to the contact witha packing material.
The static marks in photographic light-sensitive materials caused by such an accumulation of electrostatic charge becomemore conspicuous upon raising the sensitivity of the photographic light-sensitive material and upon accelerating the processing rate.
The above-described frictional or delamination charging can be attributed to ionic mutual interaction between molecules of materials in contact with each other. It is difficult at the present time to predict what materials will be positively charged and what materials will be negatively charged, and the viewpoint of structural chemistry.
However, it can be imagined that this charging can be prevented by reducing the charging voltage or by increasing the surface electroconductivity, thereby enabling the surface to dissipate electrostatic charges before partial discharge due to the accumulation of charge. Therefore, it has been attempted to improve the electroconductivity of the support or various coated surface layers in photographic light-sensitive materials by using various hygroscopic substances, water-soluble inorganic salts, certain kinds of surface active agents, and the like.
For example, one method for directly providing a photographic film support with an antistatic property comprises incorporating the compounds as described above in a high molecular weight support or applying such compounds or substances to the surface of the support. In the latter case, an antistatic agent is independently applied as a backing layer to the surface or in combination with a high molecular weight substance such as gelatin, polyvinyl alcohol, cellulose acetate or the like. In addition, it is known to incorporate an antistatic agent in a protective layer provided on the surface of a photographic emulsion or to coat an antistatic solution on the protective layer. However, a number of these substances show very high specificity for use, depending upon the kind of film support used or a difference in photographic compositions, so that while a particular antistatic substance provides good results with particular film support, photographic emulsion and other photographic constituents, it is of no antistatic use with respect to other film supports or photographic constituents, and, in fact, exerts in some cases detrimental effects on photographic properties.
In general, for highly sensitive emulsions there are few antistatic materials which are good, particularly under low humidity conditions. Many antistatic materials undergo a reduction in antistatic effect with the passage of time, or are accompanied by adhesion problems at elevated temperatures.
As is described above, using an antistatic agent with a photographic light-sensitive material is, in many cases, difficult, and the range of the use is limited. Therefore, it has been attempted to use various different types of antistatic agents in the photographic field.
SUMMARY OF THE INVENTION In the above formula, R and R, which may be the same or different, each represents an aliphatic hydrocarbon residue having 1-22 carbon atoms, the sum of the carbon atoms of R and R being 6-40, A represents a divalent aliphatic hydrocarbon residue having a total of 4-8 carbon atoms, M represents a hydrogen atom, a metal atom or a quaternary ammonium salt, and m represents a number corresponding to the valence of M.
That is, the generation of static marks can be markedly reduced by using the compound represented by the above-illustrated general formula in accordance with the invention applied to a backing or surface layer or incorporated in a backing or surface layer at the exterior of the element, which static marks result from the contact between the emulsion-coated surface of a light-sensitive material and the backing layer thereof and contact between the emulsion-coated surface and a substance with which a photographic light-sensitive material generally comes into contact, such as a rubber, metal, plastic or a fluorescence-sensitizing paper (used for X-ray films).
DETAILED DESCRIPTION OF THE INVENTION Particularly surprising, when compounds analogous to those to be used in the invention, such as or the like or a known surface active agent, are applied as a backing layer, a photographic material will always be positively, charged when brought into contact with the above-described substances, whereas in the case of the compounds used in the invention a photographic material will be negatively charged, as will be demonstrated in the Examples described hereinafter. ln general nearly no compounds were known which functioned to negatively charge a light-sensitive material upon contact with the above-described substances. Antistatic agents which function to positively charge a light-sensitive material are overwhelming in number.
In addition, the compounds of the invention have the tendency that the charging or amount approaches zero with an increase in the amount of the compound added. Therefore, the feature of the compounds used in the invention is that electrification series can be freely controlled to zero or to the negative side by properly adjusting the amount of the compounds or by combining the compounds with an antistatic agent capable of positively charging the photographic material.
It hasnot yet been verified by what mechanism the compounds of the invention are capable of negatively charging a photographic material and what relationship exists between the negative electrification and the antistatic effect. However, as a result of our experiments we found that the antistatic capability is excellent when a photographic light-sensitive material is slightly negatively charged (up to 50 V at most) rather than when positively charged.
Of the compounds represented by general formula (I) used in the invention showing the above-described effects, those wherein the carbon atoms of R+R are 6-22 in number are in general preferred.
As the metallic atom, there can be illustrated any of those metals which form a salt, such as the alkali metal atoms, e.g., Li, Na, K, etc., the alkaline earth metal atoms, e.g., Mg, Ca, and Ba, and Zn, Al and the like.
c H o so Na Ofthese, Na, K, Mg, Ca, etc. are particularly preferred. 9 19 2 3 3 Specific examples of compounds used in the invention are illustrated below.
9 3 Compound 1 I OH CH 0- 3 1 CH C OCH GH CH CH SO Ra Continued Compound 13 C' H 'fiOCHCH CHSO Na CH3 CH2CH2CH3 Compound 14 C H -t o'oHcH cH so Na CH CH (I)llCH Compound 15 OCI-ICHZCH CH SO Na CH2CH3 These compounds used in the invention can be syn- ,thesized by various known processes, for example, by
: nol or like solvents, and, even when added to a photographic emulsion, exert no detrimental influence on the photographic properties thereof such as sensitivity, gamma, fog, etc.
The compounds used in the present invention are used in an amount vof from abou't0.005 g to about 2.0
g, particularly preferably from 0.01 to 0.4 g, per 1 m of the photographic film base. Of course this amount can be varied within the range set forth depending upon the kind of photographic film base, stratum structure, element, form, coating method, and the like.
In applying the compound used in the invention to the surface of a photographic film, the compound can be applied thereto by spraying or coating on the surface of a support or on the photographic layer of a photographic film after dissolving the compound in water, organic solvent(s), or a mixture thereof, or by immersing the support or photographic film in such a nongelatin containing solution, followed by drying.
The compounds may also be used together with a binder. Illustrative binders are cellulose derivatives such as cellulose diacetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, cellulose acetate succinate, cellulose tripropionate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, or ethyl cellulose, and also synthetic polymers and copolymers of a polymerizable monomer such as styrene, vinyl ethers, vinyl esters, acrylic acid esters, vinyl ketones, vinyl chloride, acrylonitrile and maleic acid, etc., may be employed as a binder.
The antistatic agent of the present invention can also be used in combination with other antistatic agents. In addition, in the antistatic layer there may be incorporated various additives desired for various purposes, such as a hardening agent, a lubricant, a matting agent, an antihalation dye, and the like. Furthermore, the compound used in the invention can be applied to filmshaped products of cellulose esters, polyesters, polystyrenes, polycarbonates, or vinyl resins such as polyethylene, polypropylene, etc., for antistatic purpose. They are suitable for non-photographic uses as well.
Troubles due to electrostatic charging during the steps of producing photographic light-sensitive materials or upon use thereof can be remarkably reduced by the present invention. For example, charging upon mounting a photographic film in a cassette or in a camera can be effectively prevented even under low humidity conditions, and the antistatic effect will not deteriorate with the passage of time. Furthermore, a photographic film to which the compound used in the invention has been applied has the feature that when the emulsion-coated surface is brought into contact with the back surface at elevated temperature and under high humidity they do not adhere to each other.
The effects of the present invention will now be illustrated more specifically by Examples and Reference Examples, which, however, should not be construed as limitative but as illustrative.
The antistatic capability of compounds in the Examples and Reference Examples was determined by measuring the charging amount, surface resistivity, and the formation of static marks. Unless otherwise indicated all parts and percents are by weight.
The charging amount was measured by rolling a test piece, l l5 cm, with a rubber roller under a load of 380 g and at a rate of 33 cm/sec., then allowing it to fall in a Faraday cage. The reason why a rubber roller was used for estimating the charging amount is that rubber was considered to be representative of the substances above since it is essentially in the center of the electrification series with plastic, metal, paper, cotton, etc.
The surface resistivity was measured by placing a test piece between brass electrodes 10 cm in length with an electrode gap of 0.14 cm (the portion of the electrodes in contact with the test sample were made of stainless steel) and measuring 1 minute values by means of an insulation resistance tester (MM-V-M type, made by Takeda Riken Kogyo K.K.).
The static marks were produced on an unexposed film on a rubber sheet with the back surface of the film facing the rubber sheet by pressingthe assembly from above with a rubber roller followed by delamination.
The charging amount and the surface resistivity were measured at 23C and 65 percent RH, whereas the static mark-generating test was conducted at 23C and 30 percent RH. Additionally, air conditioning for the test pieces was conducted for 1 day and 1 night under the aforesaid temperature and humidity conditions prior to testing.
antistatic solution having the following composition to coat the sheet, directly followed by heat-drying in air at 120C for 30 minutes to form an antistatic layer of 0.3 micron in thickness.
Composition of the antistatic solution:
Antistatic solution (I); a 5% by weight methanol solution of the compound of the present invention (Compound 5 illustrated before) Binder solution (11); a 5% by weight cellulose triacetate solution (mol weight about 80,000 solvent: methylene dichloridezmethanol=92z8 in weight ratio): 12 g Solvent (Ill); Phenol: 2 g Tetrachloroethane: 8 g Ethylene chloride: 70 g Solvent (1V); methanol 20 g (including the amount added to antistatic solution (1)) Antistatic solution (1) was weighed out in such amount that the content of the effective, antistatic ingredient contained therein became l, 3, 5 or 10 per cent based on the binder. To each weighed solution solvent (IV), binder solution (Il) and solvent (Ill) were added.
On the side opposite to the antistatic layer there was provided a negative high speed emulsion layer containing 6 percent gelatin and 12 percent of silver bromoiodide to prepare photographic films. The antistatic capability of the resulting films was measured. The results obtained are shown in Table 1.
Table 1 Antistatic Content of Charg- Surface Static Agent Antistatic ing Resist- Marks Agent Based Amount ivity on Binder (V) (ohm) by weight) Compound (5) +60 not less than E of the pre- 10" sent invention 1 70 not less than D 101 3 -50 x l0 A-B 5 -16 l X A 10 l5 2 X 10" A The generation of static marks was examined by development processing each film in a developer having the following composition, fixing with a common fixing solution containing sodium thiosulfate, then washing and drying. Developer Compositiion:
N-Methyl-p-aminophenol Sulfate 4 g Anhydrous Sodium Sulfite 60 g Hydroquinone 10 g Sodium Carbonate (monohydrate) 53 g Potassium Bromide 25 g Water to make 1 liter The generation of static marks was rated by the following 5 grades.
A: No static marks were observed.
B: A few static marks were observed.
C: Static marks were observed in moderate quantity D: Static marks were observed in substantial quantity E: Static marks were observed over the entire surface.
REFERENCE EXAMPLE The charging amount and the sign of the charge in the case of the compound of the present invention were compared with those of a compound analogous to the compound of the present invention. The results are shown in Table 2. The thickness of the layer was 0.3 micron.
Comparative compounds Compounds of the present invention:
Illustrated compound 5 -Continued Illustrated compound 10 t-C H l1 OCH CH CHSO Na Table 2 Antistatic Content of Charging Surface Agent Antistatic Amount Resistivity Agent Based (V) (ohm) on Binder by weight) Compound (5) 2 60 l X of the present inven- 4 -30 2 X 10 tion Compound (6) 2 l06 4 X 10 of the present inven- 4 45 6 X l0 tion Compound (10) 2 80 l X l0 of the present inven- 4 35 2 X l0 tion Comparative 2 3O 3 X l0' compound (A) Comparative 2 5 l X l0 compound (B) Comparative 2 50 2 X l0 compound (C) 4 22 3 X IO Comparative 2 l8 9 X 10" compound (D) Control 0 50 not less than As is clear from the results given in Table 2, the charge in the case of the comparative compounds was always positive, whereas the charge in the case of the compounds of the present invention was negative. This fact shows one great feature of the compounds of the present invention. In addition, surface resistivity was reducued to a degree the same as or more than with the known antistatic agents. I
EXAMPLE 2 An antistatic solution having the following composition was applied to one surface of a cellulose acetate films (127 microns in thickness) to form a backing layer (0.3 micron in thickness) and a negative emulsion layer for cinema (10 microns in thickness) was provided on the opposite surface to prepare movie films.
Composition of the Antistatic Solution:
Compound (5) of the 0.5 g present invention Known antistatic agent f5 lf g N\ NaO s N/ 1i 23 Distilled water cc Cellulose acetate phthalate (mol weight about 150,000) 2 g Triethanolamine 2 g Methanol 600 00 The antistatic capability of the back surface of the resulting films was measured. The results are shown in Table 3.
Table 3 Charging Surface Resis- Amount (V) tivity (ohm) Known antistatic agent alone 50 5 X 10 Combined use of compound (5) l0 5 X l0 of the present invention and the known antistatic agent EXAMPLE 3 An antistatic solution having the following composition was applied to the back surface of a polyethylene terephthalate film (in a dry thickness of 0.3 micron), and an emulsion for use in indirect X-ray photography containing 9 percent of gelatin and 9 percent of silver halide was applied to the opposite surface.
Composition of the Antistatic Solution:
Antistatic solution (I); a 5% by weight methanol solution of compound (6) of the present invention Antistatic solution (ll); :1 5% by weight methanol solution of comparative compound (A) Binder solution ("1); a 0.3% by weight solution of cellulose triacetate (mol weight: about 80,000 solvent: methanol: ethylene chloride: tettachloroethane: phenol=8:70:8:2 in
weight ratio): 93 g Solvent(IV Antistatic solution (1) containing the compound of the present invention was added to binder solution (III) in such an amount that the content of the antistatic ingredient was 1 percent based on the binder, and antistatic solution (II) was added thereto in such an amount that the content of the antistatic ingredient was 2, 3 or 5 percent based on the binder, and finally, solvent (IV) was added thereto.
The charging amount, surface resisitivity and generation of static marks on the back surface of the processing films are shown in Table 4.
not less than 16 By using the compound of the present invention in combination with the known antistatic agent, the charging amount was lowered to zero or slightly to the negative side with the surface resistivity being low. The generation of static marks was examined in the same manner as in Example 2. Static marks were almost not present in films wherein the compound of the invention and the known compound were used in combination, while static marks were significantly formed in films wherein the compound of the invention was not used. These results show that the combined use of the compound of the invention and the known antistatic agent provides a better antistatic effect than in the independent use of the antistatic agent.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
What is claimed is:
1. An antistatic photographic light-sensitive material having thereon a surface layer comprising a non-gelatin containing binder and an antistatic compound represented by the following general formula:
wherein R and R, which may be the same or different, each represents an aliphatic hydrocarbon residue having 1-22 carbon atoms, the sum of carbon atoms or R and R being 6-40, A represents a divalent aliphatic hydrocarbon residue having 4-8 carbon atoms in total, M represents a hydrogen atom, a metal atom or a quaternary ammonium salt, and m represents a number corresponding to the valence of M.
2. The antistatic photographic light sensitive material of claim 1, wherein the thickness of said layer ranges from about 0.2 p. to about 10 11..
3. The antistatic photographic light sensitive material of claim 1 wherein M is an alkali metal atom or an alkaline earth metal atom.
4. The antistatic photographic light sensitive material of claim 3 wherein M is Li, Na, K, Mg, Ca or Ba.
5. The antistatic photographic light sensitive material of claim 1 wherein M is Zn or Al.
6. The antistatic photographic light sensitive material of claim 1 wherein said antistatic compound is present at from about 0.005 to about 2 g per 1 m of surface area of said material.
7. The antistatic photographic light sensitive material of claim 1, wherein said binder is a cellulose derivative or a synthetic polymer or copolymer.
8. The antistatic photographic light sensitive material of claim 7 wherein said cellulose derivative is cellulose diacetate, cellulose triacetate, cellulose acetate .propionate, cellulose acetate butyrate, cellulose acetate phthalate, cellulose acetate succinate, cellulose tripropionate, carboxymethyl cellulose, hydroxye'thyl cellulose, hydroxypropyl cellulose, methyl cellulose, or ethyl cellulose and said synthetic polymer or copolymer is a polymer or copolymer of a polymeriazble monomer selected from the group consisting of styrene, vinyl ethers, vinyl esters, acrylic acid esters, vinyl ketones, vinyl chloride, acrylonitrile and maleic acid.
9. The antistatic photographic light sensitive material of claim 1 wherein said surface layer is a backing layer.
10. The antistatic photographic light sensitive material of claim 1 wherein said surface layer is a protective layer.
11. The antistatic photographic light sensitive material of claim 1, wherein said antistatic compound is Compound 1