Claims
- 1. In a composition for developing diazotype material, comprising an aqueous solution of an azo-coupling component comprising phloroglucinol and a buffering agent in an amount sufficient to give said solution a pH between 5.5 and 8, the improvement comprising that said solution also contains, in addition to said buffering agent, a sorbic compound selected from the group consisting of sorbic acid, alkali metal, ammonium, and magnesium salts of sorbic acid and mixtures of the same, said sorbic compound being present in an amount sufficient to shift toward neutrally black the hue of the dyestuff formed by reaction of said solution with a diazonium salt of which the in vitro coupling activity is higher than that of p-diazo-o-chloro-diethylaniline.
- 2. A developing composition according to claim 1 wherein the amount of said sorbic compound is 10 to 80% by weight of the maximum amount thereof that is soluble in said solution at room temperature.
- 3. A developing composition as claimed in claim 1 wherein the amount of said sorbic compound is 30 to 60% by weight of the maximum amount thereof that is soluble in said solution at room temperature.
- 4. A developing composition as claimed in claim 1, said buffering agent consisting at least partially of one or more compounds selected from the group consisting of alkali metal, ammonium and magnesium salts of buffer acid other than sorbic acid and the total amount of buffer acid, calculated by including the buffering capacity of said agent and any buffering capacity of said sorbic compound, being in the range from 0.5 to 3 gram-equivalents per liter of said solution.
- 5. A developing composition as claimed in claim 4, said buffering agent consisting essentially of one or more buffer acids selected from the group consisting of succinic, glutaric, adipic, .beta.-methyl-adipic, maleic, malonic and citric acids and one or more of the alkali metal, ammonium and magnesium salts of said acids.
- 6. A developing composition as claimed in claim 1 wherein said azo-coupling component is present in an amount of 0.1 and 0.6 gram-molecules per liter of said solution.
- 7. A developing composition as claimed in claim 1 wherein said azo-coupling component consists essentially of a mixture of phloroglucinol and resorcinol.
- 8. A diazotype material developing composition comprising an aqueous solution of 0.1 to 0.6 g. mol/1 of an azo-coupling component selected from the group consisting of phloroglucinol, resorcinol and mixtures of the same, a buffering agent in an amount sufficient to give said solution a pH between 5.5 and 8, and a sorbic compound selected from the group consisting of sorbic acid, alkali metal, ammonium and magnesium salts of sorbic acid and mixtures of the same, said sorbic compound being present in an amount sufficient to shift toward neutrally black the hue of the dyestuff formed by reaction of said solution with a diazonium salt of which the in vitro coupling activity is higher than that of p-diazo-o-chloro-diethylaniline, said amount being equivalent to 30 to 60% by weight of the maximum amount of said sorbic compound that is soluble in said solution at room temperature, said solution having a buffer acid content of 0.5 to 3 gram-equivalents per liter, calculated by including the buffering capacity of said agent and any buffering capacity of said sorbic compound.
- 9. A process for preparing a diazotype copy, comprising imagewise exposing to light a diazotype material the lightsensitive layer of which has an average thickness not exceeding 8 microns and comprises a diazonium compound of which the in vitro coupling activity is higher than that of p-diazo-o-chlorodiethylaniline, and developing the exposed material by applying to said layer 1.5 to 4.5 cm.sup.3, per square meter of exposed material, of an aqueous solution of an azo-coupling component comprising phloroglucinol and a buffering agent in an amount sufficient to give said solution a pH between 5.5 and 8, said solution containing in addition to said buffering agent a sorbic compound in an amount sufficient to shift toward neutrally black the hue of the dyestuff formed by reaction of said solution with said diazonium compound, said sorbic compound being selected from the group consisting of sorbic acid, alkali metal, ammonium, and magnesium salts or sorbic acid and mixtures of the same.
- 10. A process as claimed in claim 9 wherein the amount of said sorbic compound is 10 to 80% by weight of the maximum amount thereof that is soluble in said solution at room temperature.
- 11. A process as claimed in claim 9 wherein the amount of said sorbic compound is 30 to 60% by weight of the amount thereof that is soluble in said solution at room temperature.
- 12. A process as claimed in claim 9 wherein said solution contains 0.5 to 3 gram equivalent of buffer acid per liter of said solution, calculated by including the buffering capacity of said agent and any buffering capacity of said sorbic compound, said buffering agent consisting at least partially of one or more compounds selected from the group consisting of alkali metal, ammonium, and magnesium salts of buffer acid other than sorbic acid.
- 13. A process as claimed in claim 12, said buffering agent consisting essentially of one or more buffer acids selected from the group consisting of succinic, glutaric, adipic, .beta.-methyladipic, maleic, amlonic and citric acids and one or more of the alkali metl, ammonium and magnesium salts of said acids.
- 14. A process as claimed in claim 9 wherein said azo-coupling component is present in an amount of 0.1 to 0.6 grammolecules per liter of said solution.
- 15. A process as claimed in claim 9 wherein said azo-coupling component consists essentially of a mixture of phloroglucinol and resorcinol.
- 16. A diazotype copy having image areas thereof formed by a substantially neutrally black dyestuff, produced by a process according to claim 9.
Priority Claims (1)
Number |
Date |
Country |
Kind |
7631744 |
Dec 1976 |
NLX |
|
Parent Case Info
This is a continuation of copending application Ser. No. 853,683, filed Dec. 8, 1977 now abandoned.
US Referenced Citations (2)
Foreign Referenced Citations (6)
Number |
Date |
Country |
272298 |
Mar 1964 |
AUX |
320603 |
Apr 1929 |
GBX |
957836 |
May 1964 |
GBX |
957837 |
May 1964 |
GBX |
957838 |
May 1964 |
GBX |
1417221 |
Dec 1975 |
GBX |
Non-Patent Literature Citations (3)
Entry |
West et al., Textbook of Biochemistry, 3rd Ed., pp. 34-41. |
Lucas, Organic Chemistry, 2nd Ed., 1953, p. 196. |
Lyman, American Pharmacy, 1945, pp. 128-129. |
Continuations (1)
|
Number |
Date |
Country |
Parent |
853683 |
Dec 1977 |
|