Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/76—Photosensitive materials characterised by the base or auxiliary layers
  • G03C1/85—Photosensitive materials characterised by the base or auxiliary layers characterised by antistatic additives or coatings
  • G03C1/89—Macromolecular substances therefor

Definitions

• a process for reducing electrostatic charging of a photographic material comprising applying to the back side of the support a first layer comprising a mixture of (A) a partially neutralized copolymer of a hydrophobic monomer and a mono or dicarboxylic acid or half-ester or half-amide derivative thereof, and (B) a compatible hydrophobic polymer, and thereupon applying a protective layer of a non-tacky hydrophobic polymer.
• photographic materials tend to be charged electrostatically. Such a charging can arise during any stage of the manufacture of the photographic material, especially on rewinding such material during the different steps of its manufacture as well as on rewinding during the cutting operation. Charging also occurs during unrolling in the photographic camera.
• a process for reducing the tendency to electrostatic charging of a photographic material comprising a support and at least one light-sensitive silver halide emulsion layer, which process comprises applying successively to the back side of the support a first layer comprising a mixture of (A) a partially neutralized copolymer of a hydrophobic a,,8- ethylenically unsaturated monomer and of an a,B-ethylenically unsaturated monoor dicarboxylic acid or derivative thereof, and (B) a compatible hydrophobic polymer, said layer being applied from a water-miscible organic solvent that affects the support, and thereupon applying a protective layer of a non-tacky hydrophobic polymer that does not interfere with the photographic properties of the silver halide emulsion layer.
• the combination of an antistatic layer and of a hydrophobic protective layer confers excellent antistatic properties to photographic film manufactured on the basis of a cellulose ester support, such as cellulose triacetate, cellulose propionate, cellulose butyrate, and of cellulose mixed esters, such as cellulose acetate-butyrate.
• a cellulose ester support such as cellulose triacetate, cellulose propionate, cellulose butyrate, and of cellulose mixed esters, such as cellulose acetate-butyrate.
• the combination of antistatic layer and of hydrophobic protective layer can successfully be applied to other photographic supports, e.g. in the case of photographic paper which has been provided with a covering layer from a cellulose compound, such as nitrocellulose, cellulose esters or ethers, occasionally mixed with another hydrophobic polymer.
• the mixture forming the first layer adjacent to the cellulose ester support comprises a partially neutralized copolymer formed of hydrophobic and of hydrophilic monomeric units.
• the hydrophobic units derive from monomers capable of enhancing the sensitivity of the copolymer to organic solvents.
• hydrophobic a,/3-ethylenical1y unsaturated monomers such as styrene and its derivatives, e.g., nitrostyrene, and vinyl toluene, vinyl acetate, vinyl alkyl ethers, alkyl acrylates and alkyl methacrylates.
• the hydrophilic units originate from a,, 3-ethylenical1y unsaturated monoor dicarboxylic acids and their derivatives such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid, as well as their half-esters and half-amides.
• the copolymer is applied in its partially neutralized form which means that a sufficient amount of alkali metal hydroxide has been added to the copolymer in order to raise the pH to about 7.
• the molecular Weight of the copolymer may vary within very Wide limits, since in the case of the copolymer of styrene and maleic acid, similar results have been obtained with molecular weights varying between 10,000 and 350,000.
• the above copolymer is mixed with a compatible hydrophobic polymer such as cellulose diacetate, cellulose propionate, cellulose butyrate, cellulose acetate-butyrate, hydroxyethylcellulose acetate, phenol-modified coumaronindene resin, poly(methyl methacrylate), and copolymers of styrene and allyl alcohol.
• a compatible hydrophobic polymer such as cellulose diacetate, cellulose propionate, cellulose butyrate, cellulose acetate-butyrate, hydroxyethylcellulose acetate, phenol-modified coumaronindene resin, poly(methyl methacrylate), and copolymers of styrene and allyl alcohol.
• the hydrophobic copolymer which can be regarded as the binding agent for the layer adjacent to the cellulose ester support, has to be soluble in a water-miscible organic solvent, which is able to affect the surface of the cellulose ester support as will be further explained hereinafter.
• Solvents such as acetone, butanone, tetrahydrofuran and their mixtures occasionally also with water or methanol, are very suitable in the process of the invention.
• a protective layer of a non-tacky, hydrophobic polymer is applied, which firmly adheres to the first one, which does not interfere with the photographic properties of the light-sensitive silver halide emulsion layer, and which is resistant to abrasion during manipulation in the photographic apparatus.
• any hydrophobic polymer can be employed when it satisfies the above enumerated criteria.
• polymers such as cellulose diacetate, cellulose triacetate and copolymers of vinylidene chloride and acrylonitrile.
• friction-reducing compounds such as waxes may be added to the layer composition.
• a photographic film material is mainly composed of a cellulose ester support, a subbing layer and a light-sensitive silver halide emulsion layer.
• the object of the subbing layer is to firmly make adhere the hydrophilic lightsensitive layer to the hydrophobic support.
• the subbing layer always is applied from a solution in solvents which more or less affect the support surface.
• a first layer is applied consisting of a mixture of partially neutralized copolymer and of a hydrophobic polymer that functions as binding agent for such copolymer.
• the mixture thus has to contain a certain amount of hydrophopic polymer, e.g. cellulose diacetate.
• hydrophobic polymer enhances the strength of the layer whereby its scratch resistance is increased and the deposition of dust from this layer onto the photographic apparatus during unwinding is diminished.
• the copolymer of hydrophobic monomer and of a,fl-ethylenically unsaturated monoor dicarboxylic acid forms a very effective antistatic the properties of which even after having been mixed with a hydrophobic binding agent are still sufficient.
• the antistatic copolymer is mixed with an equal or double amount of the hydrophobic binding agent to be worked up into a layer.
• the aqueous solution of the antistatic copolymer can be diluted with organic solvents, such as alcohols and ketones, by which mixing with the solution of the hydrophobic polymer is made possible.
• a good coating composition for the first layer is obtained by mixing:
• the main purpose of the protective layer is to increase the scratch resistance of the material and especially to maintain the good electrostatic properties of the photographic material even after processing in the photographic baths, so that attraction of dust is strongly diminished also after processing. If less interest is taken in the antistatic properties of the processed material, occasionally the protective layer can be omitted. In such a case the electrostatic properties of the first layer would be lost by processing, such as usually is the case with the known antistatic layers. According to the invention, however, the second layer of hydrophobic polymer prevents the disappearance of the antistatic properties in the photographic baths, with the result that the finished photographic images will attract much less dust.
• the antistatic properties are mostly obtained by the use of hydroscopic products, which however have the disadvantage that they form sticky layers at higher values of relative humidity of the surrounding atmosphere. Since in the process of the invention the actual antistatic layer is covered with a hydrophobic layer, this disadvantage ceases to xist.
• the combination of antistatic layer and of Protective layer according to the invention normally is applied to the photographic support before the light-sensitive silver halide emulsion layer or layers are coated. Indeed, the combination decreases the susceptibility of the material to be charged electrostatically. Hereby, the number of failures which could arise during the application of all further layers and during the rewinding in the different steps of manufacture and processing is greatly diminished. At the same time the deposition of dust onto the photographic material during these manipulations is decreased considerably.
• the determination of the antistatic properties of the photographic material has been carried out by measuring the surface resistivity according to the method described in DIN 53,482 of October 1955. All the figures in the examples originate from measurements on the back side of the photographic material, i.e. on the side of the combination of antistatic layer and protective layer according to the invention.
• EXAMPLE 1 A film support of cellulose triacetate which has been coated on the front side with a known subbing layer, is coated on the back side with an antistatic layer in a proportion of 45 sq. m. per liter from the following solution:
• the surface resistivity of the back side of this photographic material has been measured after having conditioned the material at 30 and 60% respectively of relative humidity before as well as after processing in the normal photographic baths.
• Example 1 is repeated but the antistatic layer now has been formed from the following solution in a proportion of 40 sq. m./ liter:
• a protective layer as in Example 1 is applied to the antistatic layer and a photographic silver halide emulsion layer to the front side of the support.
• the values of surface resistivity are the following:
• EXAMPLE 3 One side of a film support of cellulose acetate-butyrate having a substitution degree of acetyl groups of 2 and of butyryl groups of about 0.75 is provided with a subbing layer. Then the other side of the support is coated with an antistatic layer from the following solution in a proportion of 40 sq. m./ liter:
• Example 2 is repeated but as protective layer a coating is applied in a proportion of 46 sq. m/liter from the following solution:
• the finished photographic material possesses the following values of surface resistivity:
• EXAMPLE 5 A cellulose triacetate support is provided with a subbing layer. Then the other side of the support is coated with an antistatic layer from the following solution in a proportion of 44 sq. m./1iter:
• EXAMPLE 7 To the back side of a cellulose triacetate film the front side of which has been provided with a known subbing layer, an antistatic layer is applied from the following solution in a proportion of 41 sq. m./ liter:
• resistivity of the photographic material obtained yielded 30% RH 3.10 l i2/ 10 sq. cm. the following results: 60% RH 0.O55 10 i2/1O sq. cm.
• a determined length of the photographic film of Exam- 10 What We claim is:
• ple 1 is cut and perforated as is usually don f h 1.
• Process for reducing the tendency to electrostatic manufacture of cinematographic film A length of about charging of a Photographic material Comprising a P- 6 to 7 f h fil h b i d i processed i th port and at least one light-sensitive silver halide emulnormal photographic baths. After having been dried, both SiOn ye hich Comprises applying successively to the ends of the film are spliced so that a loop is obtained.
• this loop is placed in a usual copying apparatus ture of a p i y heutfallled copolymer of a yand continuously printed 300 times on cinematographic droph ,5-? Y Y unsaturated n0mer and of positive film. After 1, 100, 200 and 300 prints, the material hl t f y unsaturated 1110110- diCE-FbOXYIiC is controlled as to scratches and deposition of dust.
• the partially a very li l scratching neutralized copolymer is a copolymer of styrene and 2; a degree of sgratching hi h i t hindering f maleic acid, which has been partially neutralized with an photographic purposes alkali metal hydroxide to pH 7.
• com- Dust patible hydrophobic polymer is taken from cellulose di- 0: no dust acetate, hydroxyethyl cellulose acetate, a copolymer of 1: avery small quantity of dust styrene and allyl alcohol, and a phenol-modified cou- 2: a quantity of dust which is not hindering for photomaron-indene resin.
• a quantity of dust which is hindering for photographic layer is formed from the group consisting of cellulose purposes dlacetate, cellulose triacetate, hydroxyethyl cellulose ace- 4: a quantity of dust whereby the photographic material a a d a copo ymer of vinylidene chloride and acrylois not usable at all. nrtrile.
• a light-sensitive material comprising a support and To the back side of a subbed cellulose triacetate film at least one light-sensitive silver halide emulsion layer an antistatic layer is applied from the following solution on one side, and on the back side of the support a first in a proportion of 48 sq. m./liter: layer comprising the dried residue of a mixture of (A) Ccs.
• a protective layer is applied thereto as in Example 3. 'Ihereupon the front side of the material is coated with a photographic gelatino silver halide emulsion layer.

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• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Coating Of Shaped Articles Made Of Macromolecular Substances (AREA)
• Laminated Bodies (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Applications Claiming Priority (1)

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Cited By (7)

Citations (5)

• 1966
  • 1966-10-04 GB GB44724/66A patent/GB1172999A/en not_active Expired
• 1967
  • 1967-03-23 NL NL6704313A patent/NL6704313A/xx unknown
  • 1967-03-31 DE DE1967A0055309 patent/DE1522438B2/de active Granted
  • 1967-03-31 US US627320A patent/US3514291A/en not_active Expired - Lifetime
  • 1967-03-31 BE BE696363D patent/BE696363A/xx unknown

Patent Citations (5)

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