Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C309/00—Sulfonic acids; Halides, esters, or anhydrides thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
  • C08G65/34—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from hydroxy compounds or their metallic derivatives
  • C08G65/48—Polymers modified by chemical after-treatment
  • C08G65/485—Polyphenylene oxides
• • 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
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/04—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with macromolecular additives; with layer-forming substances
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S525/00—Synthetic resins or natural rubbers -- part of the class 520 series
  • Y10S525/905—Polyphenylene oxide

Definitions

• the silver halide is precipitated in gelatine solution and the resulting emulsion thereafter solidified by cooling and the gel is cut into pieces and freed from soluble salts by washing with cold water.
• this process necessitates certain rinsing periods.
• the volume of the gel increases to a large or small degree and frequently an undesired lowering of viscosity occurs. This must often be compensated for by adding gelatine during the subsequent melting (ripening or casting). Using this process, it is difficult to vary the ratio between silver halide and gelatine as required.
• the emulsions are coagulated by adding a precipitant to remove the excess salts, separated from the supernatant aqueous. solution containing the salts in dissolved form, washed with water and, after adding more gelatine solution, often also redispersed. by adjusting the pH to a predetermined value. It is possible in this way to obviate the rinsing operation which occupies a considerable time.
• the emulsion character can be varied greatly and improvements in the photographic properties can be obtained.
• the gelatine solution must have a minimum concentration of about 23% in order to achieve the gelling of the gelatine.
• the increasing importance of this flocculation process is illustrated by the large selection of variants of the process which have become known in recent times. They 'dilfer from one anotherv more especially by the nature of the precipitant.
• the oldest method of flocculating gelatino-silver halide emulsions is salt flocculation.
• An excess of, for example, sodium sulphate is added to the emulsions and the gelatine flocculates out with the silver halide.
• the disadvantage ofthis method lies in the great excess of salt which is necessary for a complete flocculation.
• precipitates cannot be washed out with water, since they are easily dissolved again. After the washing process, the emulsions still show a certain conductivity, which is attributed to a high residual content of salts.
• Another method of flocculating emulsions consists in chemically converting the gelatine.
• gelatine can be reacted with phthalic acid. anhydride and added to the batch gelatine.
• a 3,137,576 Patented June 16, 1964 can be precipitated in aqueous solution at pH 3. How ever, the production of the gelatine derivatives often leads to difi'iculties as high pH values (in the region of 10) must be used during the reaction. As a result, some of the gelatine is decomposed. Furthermore, derivatives of this type do not permit the production of highly sensitive emulsions. When using these flocculating agents, the photographic properties of the emulsion are so greatly influenced that these precipitation methods cannot be used on existing and tested emulsion recipes, sincethey influence the composition of the ripening and inhibiting elements to a large extent. For these reasons, a complete redevelopment of the photographic emulsion concerned is usually necessary. This disadvantage has hitherto prevented the practical use of this process.
• High-molecular acid-insoluble compounds with carboxyl groups have also been proposed as flocculants.
• the relatively low flocculation pH value and the modification of the physical properties of the gelatine for example, the water permeability, the high swelling, the modified adhesion and the impaired redispersability, constitute disadvantages.
• Benzaldehyde sulphonic acid acetals of polyvinyl alcohol have also been described as flocculants, but these have the disadvantage that the coagulates of the acetalsulphonic acids and gelatine are only formed at pH values below 3.
• salts of water soluble high molecular weightpolyphenylene oxides containing sulphonic acid groups precipitate silver halide emulsion at pH values of 3.5-6.
• the subtances can be used according to the invention for precipitating'all types of such emulsions.
• they are especially'suitable for emulsions having a lowgelatine'content and a particularly high 'silver'halide content, such emulsions are characterised by a silver halide gelatine proposition of at least 1 g. silver halide per 1.5 g. of dried gelatine.
• a precipitation from highly diluted aqueous solution also occurs without it being necessary to addsalts or organic liquids.
• the gelatine is'completely precipitated by the substance according to the invention.
• the photographic properties of the silver halide emulsions-or the gelatine compositions are not changed thereby.
• By-means of the process according to the invention it is possible for any desired silver halide emulsion to be produced'subst'antially more easily than was possible with the hitherto known processes.
• the compounds according to the invention are particularly advantageous over prior art because they are capable of almost completely precipitating the gelatine respectively the silver halide. Thus a loss of silver salts is avoided.
• polyphenylene oxides of the general formula:
• R to R represent hydrogen atoms or an alkyl radical containing 1 to 3 carbon atoms
• A represents a 'hydrogen atom or a --SO Me-group, but 1 to 3 and preferably 2 neutralised sulphonic acid groups must be present for each formula unit (i.e. for every three phenylene oxide radical)
• Me represents any desired alkali metal such as sodium or potassium, alkaline earth metal by magnesium or calcium or ammonium cation, for example, ammonium or alkyl ammonium cations and n represents an integer between 3 and 100.
• the advantage of this compound is that for completely precipitating gelatine at a pH value of 3.5-6, it is only necessary to use a relatively small quantity, namely 8 to 20% and advantageously 10l2% of the weight of gelatine, so that the fiocculate can be washed out extremely satisfactorily and so that the fiocculate can be redispersed very quickly and without residue by adjusting the pH value to about 7 and by gently heating the mixture to 35-45 C.
• the compounds according to the invention do not have any deleterious eli ect on the photographic properties of the silver halide emulsion. This was not to be expected, since, for example, aliphatic polyethylene oxides are known to have strong influence on the sensitivity of photographic emulsions. In the case of the polyphenylene oxides used according to the invention, the sensitivity and the gradation of the emulsion are not changed. The emulsion is only improved by suppressing the fogging, probably due to the possibility of being able to redisperse the coagulate quicker.
• the production can be supplied by this method while maintaining the tested emulsion recipes.
• the procedure adopted is that the silver halide is precipitated in the batch gelatine. 23-20% of a water-soluble salt of polyphenylene oxide sulphonic acid, calculated on the quantity of gelatine used is added to this dispersion. The pH value is then adjusted to between-3.5 and 6.
• the emulsion coagulates in the form of fine flakes, the size of' which can be varied within certain limits by adjusting to a predetermined temperature. Large flakes and coherent coagulates are obtained when working at relatively high temperatures.
• the supernatant liquid is removed by decantation and the precipitate is washed several times with cold water; The residue can be redispersed extremely easily and quickly with water at a temperature below 45 C. by adding alkali until a pH value of 78 is reached.
• the required quantity of gelatine is added and the emulsion is ripened.
• the conventional additives such as sensitisers, stabilisers and hardeners, can also be added.
• the pH is adjusted to a value of 3.54 and the substance is cooled to 12' C. above the solidification point of the gelatine. If an aqueous solution of a salt of the polyphenyl sulphonic acid is added under these conditions, the emulsion precipitates in finely divided form and can be extracted by suction filtering. The redispersion then proceeds even more quickly.
• the method referred to can also be used in order to produce new emulsions with extremely high silver halide content.
• T hus highly sensitive silver halide layers based on synthetic plastics, for example, polyvinyl alcohol, hydroxyethylcellulose or cellulose esters, can be produced. These were otherwise only obtained with photographically active .gelatine.
• the sulphonic acids of the polyphenylene oxides have, as yet, not been described in the literature.
• Polyphenylene oxides are known and they are prepared from the corresponding phenols.
• Aqueous solutions of pbromophenols are condensed with sodium hydroxide solution, sodium bromide being split off (JACS 82 (1960), No. 14,
• the corresponding dialkyl phenols are condensed by oxidation, the phenol being dis.- solved in nitrobenzene and oxygen being introduced in the presence of cuprous salts and pyridine (JACS 81 (1959), 5
• Example 1 A photographic emulsion is prepared from the following solutions by mixing at 50 C.:
• the mixture is cooled to 20 C., the supernatant liquid is poured off and the coagulate is Washed with cold water.
• the coagulate is thereafter redispersed by adding 24 g. of gelatine in 300 cc. of water at 40 to 50 C., the pH value being adjusted to 7.
• the emulsion has the same sensitivity as the emulsion prepared in conventional manner and the gradation has also not changed.
• Example 2 A photographic emulsion is prepared by mixing the following solutions:
• Solution B 700 ml. of water 300 g. of potassium bromide 6 g. of potassium iodide 70 g. of gelatine
• the solution A is added dropwise over a period of 30 minutes at a temperature of 40-45 C. to the solution B while being thoroughly stirred.
• 70 cc. of a 10% aqueous solution of the sodium salt of a poly-2,6-diethyl-phenylene oxide sulphonic acid are slowly added While continuing stirring.
• the emulsion is approximately neutralised by adding 160 cc.
• Example 3 A pho tographicemulsion is prepared from the following solutions:
• the clear solution is de-
• the flocculate is thereafter washed two or three times with cold water.
• the flakes are redispersed in 500 cc. of water at 40 C. and dilute sodium hydroxide solution is added toadjust the pH value to 7.2. .
• a solution of 200 g. of gelatine in 1.5 litres of water is added and the emulsion is ripened for about v.60. minutes at 50 C.
• the'emulsionhereby obtained does not show any change in its photographic properties.
• Example 4 An emulsion is prepared by mixing the following solutions at 45 C.:
• Solution A 900 cc. of water 15 g. of gelatine g. of KBr Solution B g. of silver nitrate 1000 cc. of Water Solution B is added to solution A and, after cooling the mixture to 35 C., 15 cc. per 1 litre of emulsion of a 10% solution of the sodium salt of an unsubstituted polyphenylene oxide sulphonic acid is added.
• the pH is adjusted to 4.0 to 4.5, and the emulsion flocculates out. It is thereafter decanted and the precipitate is redispersed by adding 35 g. of gelatine in 500 cc. of water after adjusting the pH to 7 and heating to 40-50 C. after the usual ripening, the emulsion obtained does not differ from an emulsion prepared in the conventional way.
• a photographic emulsion is prepared from the following solutions:
• Solution A 100 g. of silver nitrate 550 ml. of water Solution B 45 g. of sodium chloride 1200 ml. of water 12 g. of gelatine Solution A is introduced dropwise into solution B while stirring vigorously and at a temperature of 50 C. After cooling to 35 C., 600' ml. of the emulsion thus prepared is adjusted to a pH value of 4.0-4.3 with 3% sulphuric acid. The emulsion is fiocculated out and separated by decantation from the supernatant liquid by adding 15 ml. of a 5% aqueous solution of the sodium salt of poly-2,6-diethyl-phenylene oxide sulphonic acid.
• the soluble salts are removed from the flocculate by repeatedly washing with cold water.
• the fiocculate is thereafter redispersed by adding 35 g. of gelatine in 500 ml. of water. This is then heated to 40-50 C. and the pH value adjusted to 7.
• Example 6 3 samples of a silver halide gelatine emulsion are prepared, using for each sample 280 g. of gelatine 1200 g. of silver nitrate 850 g. of potassium bromide l. of Water AgBr content grams
• the pH value forthe precipitation of 3.5-6 can be adjusted by the addition of mineral acids, such as sulfuric acids or organicacids.
• mineral acids such as sulfuric acids or organicacids.
• Preferred are monoor polybasic aliphatic acids, such as acetic acid and citric'acid.
• a process for the production of photographic silver halide emulsions which comprises coagulating a silver halide dispersion in an aqueous gelatine solution by addin ⁇ ; to said solution at a pH value of about 7 a water soluble salt of a sulfonated polyphenylene oxide, adjusting the pH value to a value of between about 3.5 and 6 by addition of a water soluble acid selected from the class consisting of mineral acids and organic acids to cause the gelatine to precipitate asa coagulum from the solution; separating the coagulum from the supernatant liquid,
• R to R represents a member selected from the group consisting of hydrogen and alkyl radicals up to 3 carbon atoms
• A represents a member selected from the class consisting of hydrogen and a neutralized sulfonic acid whereby the sulfonie polyphenyl oxide contains 1-3 sulfonic acid groups for each formula unit of three phenylene oxide groupings and n represents an integer between 3 and 100.
• sulfonated polyphenylene oxide is a sulfonated 2,6-dimethyl polyphenylene oxide.
• sulfonated polyphenylene oxide is a sulfonated 2,6-diethyl polyphenylene oxide.

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  • BE BE624053D patent/BE624053A/xx unknown
• 1961
  • 1961-10-25 DE DEA38652A patent/DE1147481B/de active Pending
• 1962
  • 1962-10-15 CH CH1207562A patent/CH418125A/de unknown
  • 1962-10-16 US US231004A patent/US3137576A/en not_active Expired - Lifetime
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