Патент USA US2407602код для вставки
Patented Sept. 10, 1946 2,407,600 l‘ "UNITED STATES PATENT "OFFICE ‘ PHOTOGRAPHIC DEVELOPER, . ' ‘. Frederic R. Bean, Rochester, N. Y., assignor to > ‘ Eastman Kodak CompanyLRooheSter, ,N. Y., ‘a; corporation of New Jersey . No Drawing. Application March 3, 1945, Serial No. 580,925 2 Claims. (CI. 95-88) 1 2 This invention relates to photographic devel glassy liquid was formed in about 30—45 minutes. opers, and more particularly to developers in which the usual alkalies are replaced by a com position new for the purpose. One object of my invention is to provide an air stable, moisture-resistant alkali for use in pho tographic developers. Another object is to pro vide an alkali which will give, in photographic It was spread out and dried in a thin layer at 40° C. The product was ground to a white powder which was completely stable under ordinary at mospheric conditions. The yield was practically quantitative. A mixture of anhydroformaldehyde sulfanilate and sodium sul?te is stable and non-deliquescent, and does not absorb carbon dioxide from the air. and results as sodium hydroxide. Another object 10 It can be weighed, stored and handled with ease. is to provide a stable, noncaking, ready-mixed, dry When this mixture is dissolved in water, the fol developer powder. Still another object is to pro lowing reaction takes place: ‘ vide a stable, non-caking, ready-mixed, single dry developers, approximately the same alkalinity EH; developer powder. Other objects will hereinafter appear. $HaSOaNa N NH Alkaline developers have been known and used for many years. + NarSOa + H10 _-» O + NaOH These developers usually con tain developing agents, a so-called preservative, such as sodium sul?te, and an alkali. One of the SOaNa SO3NB. oldest and most useful alkalies used'in photo 20 The pH of a solution made by dissolving a gram graphic developers is sodium hydroxide, otherwise mole of sodium anhydroformaldehyde sulfanilate known as caustic soda. The degree of alkalinity and a gram-mole of sodium sul?te in a given which it confers upon a developer has been found amount of water is practically the same as that of to be most suitable for certain purposes. How ever, sodium hydroxide is deliquescent and corro~ 25 a solution made by dissolving a gram-mole of so dium hydroxide in the same amount of water. An sive, and for this reason is di?icult to handle, equimolecular mixture of sodium anhydroformal dehyde sulfanilate and sodium sul?te can be used weigh, store and package. Moreover, when used in ready-mixed, packaged developer powders, in place of sodium hydroxide, 333 ‘parts by weight which, because of their convenience and uniform ity, are very popular among both amateur and 30 of the mixture replacing 40 parts by weight of sodium hydroxide, in all photographic developer professional photographers, sodium hydroxide is formulae in which sodium hydroxide is speci?ed. apt to cause caking, discoloration and deteriora The compound tion of the powder. This renders impracticable the preparation of a single-powder developer con taining sodium hydroxide. 35 I have discovered that a mixture of equimolec ular proportions of sodium sul?te and sodium an hydroiormaldehyde sulfanilate is suitable for use I in photographic developers in which it is desired S OaNa to have the alkaline properties of sodium hydrox 40 ide without its undesirable properties. formed when the mixture of sodium anhydro Sodium anhydroformaldehyde sulfanilate has formaldehyde sulfanilate and sodium sul?te is the structural formula dissolved in water acts as a moderately strong CH2 SOaNa It also exerts a restraining action on photographic development. Therefore, a developer made up with this mixture shows less photographic activity than one made up with an equivalent amount of sodium hydroxide even though the pH is the same in both cases. An equimolecular. mixture of sodium anhydro formaldehyde sulfanilate and sodium sul?te can be used to prepare single-powder developers, since it does not react upon the other dry chemicals On warming to 90°-100° 0., a 55 present in the powder. It will be understood that and may be prepared as follows: Example 1._231 g. of sodium sulfanilate were mixed with '75 g. of a 40% aqueous solution of formaldehyde. stabilizing agent for alkaline solutions of photo 45 graphic developers. 2,407,600 ' 4 3 additional sodium sul?te beyond that required to make an equimolecular mixture with the sodium anhydroformaldehyde sulfanilate may be, and us ually will be, employed in the developer, to per mately together in a single container and remains stable in dry form; without discoloration. What I claim as my invention and desire to be secured by Letters Patent of the United States is: 1. _A photographic developer, in dry form, con form its usual function as a preservative. U! taining a developing agent and, as an alkali, a As an example of a single-powder developer mixture, in equimolecular amounts,1of sodium an containing my novel mixture, I give the following: hydroformaldehyde sulfanilate and sodium sul?te. p ' Example 2 ‘ Hydroquinone ___________ -.g._ 6. 0 Elon _________ -- l. 5 For use dlssolve in 300 m1. of‘ ._ -_.g_. I r Sodium sul?te ___________ __g_. 24.0 Water at about 125 F. (5(1a sulfanilate ___________ __g.. Potassium bromide_ ___g_'_ requisite for use. Sodium anhydrofor ald hyde 26.0 l. O 0.); cool to temperature This developer has all ingredients mixed inti; ' 2. A photographic developer in the form of a > single dry powder, containing a developing agent ' and, as an alkali, a‘ mixture, in'equimolecular amounts, 'of sodium anhydroformaldehyde sulf ' am‘late and. sodium sul?te. FREDERIC R. BEAN.