CS254718B1 - A method of emulsifying water-soluble colorformers - Google Patents

Abstract

A method of emulsifying water-insoluble color-forming components and other water-insoluble substances, characterized in that the water-insoluble component is dissolved in a mixture of low-boiling and high-boiling solvents and the low-boiling solvent is evaporated from the solution before emulsification.

Description

The invention relates to a method of emulsifying water-insoluble color-forming components and other water-insoluble substances used for the production of light-sensitive, silver halide and black-and-white materials.

Emulsification of water-insoluble color-forming components and other water-insoluble substances used for the production of colored or chromogenically developed black-and-white materials such as sensitizers, ultraviolet absorbers, stabilizers, etc., is carried out by emulsifying them in organic solvents with a boiling point of 170 °C or higher, which are immiscible with water. These high-boiling solvents are used for emulsification mostly in combination with low-boiling solvents, rarely alone. Low-boiling solvents enable, or accelerate, the dissolving effect.

As high-boiling solvents that are immiscible with water, di-n-butyl phthalate, benzyl sulfate, tri-o-cresyl phosphate, monophenyl-di-o-chlorophenyl phosphate, dioctyl phthalate and others are used (US 2,322,027, DE 2,536,191).

The selection of low-boiling solvents to aid in the transfer of water-insoluble materials from a solution of high-boiling solvents is very demanding, as the solvents must meet a number of technological, safety, hygienic and economic conditions (DE 2 528845,

532,225, 2,536,191), GB 1,142,553, US 2,801,171 and others).

The actual technological process in the preparation of the emulsifier consists in dissolving the water-insoluble component in a mixture of low-boiling and high-boiling solvents or solvents and mixing the solution with an aqueous gelatin solution using a cavitation stirrer at a temperature of 30 to 90 °C. The low-boiling solvent is then distilled from the gelatin emulsion.

Since a significant excess of low-boiling solvent is used for emulsification (1 to 10 times the weight of the component), distilling off the low-boiling solvent is difficult and energy-intensive. The emulsified product foams strongly during distillation, some solvents are difficult to distill off from the aqueous emulsion, and it is almost never possible to completely remove the low-boiling solvent under these conditions, so that a certain residual amount of low-boiling solvent remains in the emulsion and can cause various hygienic or safety problems during subsequent coating and drying.

Now a new method of preparing an emulsified product using a low-boiling solvent has been found.

Its principle is that the color-forming component or other water-insoluble material is dissolved in a mixture of low-boiling and high-boiling solvents, but the low-boiling solvent is distilled off from the solution before emulsification. A water-insoluble substance that has been dissolved in a high-boiling solvent with the help of the low-boiling solvent is no longer precipitated from the solution after its complete or partial removal. The solution is mixed with an aqueous gelatin solution using a cavitation stirrer at a temperature of 30 to 90 °C. In the high-boiling solvent itself, the components in the above-mentioned component - high-boiling solvent ratio do not dissolve at a temperature below the melting point of the component.

. The new technological process has a number of advantages over the previously used process. Distillation of the low-boiling solvent proceeds smoothly, without any foaming and without decomposition of the component, the low-boiling solvent can be quantitatively separated from the mixture in this way and in pure form, so that the regenerated low-boiling solvent can be used for further dissolution without further purification. Distillation is less energy-intensive and the prepared emulsifies show at least the same values as the emulsifies prepared by the original process.

Example 1 g of 5-methyl-4,6-dichloro-2/2,4-di-tert.pentylphenoxy-1-ethylacetamido/phenol (cyan component) is dissolved in a mixture of 10 ml of dichloromethane, 2 ml of dibutyl phthalate, 2 ml of p-nonylphenoxytetraethylene oxide and 0.2 g of sodium p-nonylphenoxybutanesulfonate under boiling.

After dissolving the component, the low-boiling solvent (dichloromethane) was quantitatively distilled off. The solution was emulsified into 50 ml of a 5% solution of inert gelatin using a cavitation mixer at a temperature of 50 θϋ. Emulsify A1 was formed. Emulsify A2 and Emulsify A3 were prepared in a similar manner, but without evaporating methylene chloride, from which the methylene chloride was evaporated only after emulsification.

The parameters of the emulsifiers are given in the following table.

Al Emulsifier Emulsifier A2 Emulsifier A3 Polydispersity in N-degrees 1 1.5 1.5 d-medium size particles in the um 0.29 0.32 0.28

Example 2 g of 1-pivaloyl-1-(3-chloro-1,2,4-triazolyl-2)-2-chloro-5-(2,5-di-tert.pentylphenoxybutylamido)acetanilide (yellow component) is dissolved in a mixture of 20 ml of ethyl acetate and 4 ml of dibutyl phthalate (Emulsifier B) or in 20 ml of dichloromethane and 4 ml of p-nonylphenoxytetraethylene oxide (Emulsifier C) at a temperature of 40 to 60 ° C. After dissolving the component, 95% ethyl acetate (19 ml) was evaporated from solution B and 90% dichloromethane (18 ml) was evaporated from solution C and the obtained solutions were emulsified with an aqueous solution of inert gelatin in the same way as in Example 1, Emulsifier A, and prepared into similar emulsifiers B1, B2, B3 and Cl, C2 and C3. The parameters of the emulsifiers are given in the following table.

Emulsifier Bl B2 B3 Cl C2 C3 Polydispersity 0.5 1.2 1.0 0.5 1.5 1.5 in N-degrees d-medium size 0.27 0.34 0.30 0.20 0.30 0.27

particles in yum

Example 3 g of 1-(2,4,6-trichlorophenyl)-3/3(2,5-di-tert.pentylphenoxyacetamido)benzoylamido/pyrazolone-5 is dissolved in a mixture of 15 ml of dichloromethane and 4 ml of tris(2-ethylhexyl)phosphate and emulsions D1, D2 and D3 are prepared in a similar manner to emulsion A, in example 1.

Example4

5g of 1(2,4,6-trichlorophenyl)-3-(2-chloro-5-octadecylsuccinimido)phenylaminopyrazolone-5 is dissolved in 15 ml of ethyl acetate and 5 ml of dibutyl phthalate and the solution is processed into emulsions E1, E2 and E3 in the same manner as in Example 1, Emulsions A1 to A3 were prepared. The parameters of emulsions D and E are given in the following table.

Emulsifier Dl D2 D3 Electric E2 E3 Polydispersity 0.5 1.5 2.0 0.75 1.0 1.0 in N-degrees d-medium size 0.25 0.30 0.275 0.25 0.24 0.22

particles in yum

SUBJECT OF THE INVENTION

Claims (1)

SUBJECT OF THE INVENTION A process for emulsifying water-insoluble color forming components and other water-insoluble substances, characterized in that the water-insoluble component or water-insoluble substance is dissolved in a mixture of a high-boiling and low-boiling solvent and the low-boiling solvent is evaporated from the solution prior to emulsification.