DD298210A5 - METHOD OF CLEANING THE MEDIUM FOR THE RECIPIENT RECOVERY FROM PHOTOGRAPHIC FILM WASTE - Google Patents

Abstract

The invention relates to a method for cleaning the carrier material in its recovery from wastes of photographic films, which can be used in the photochemical industry and in the treatment of unusable scrap films. The process of the present invention, after removal of the photographic layers and the backing layers and subsequent spooling processes, provides a washing process in water with the addition of a detergent formulation and addition of an organic solvent such as xylene in a temperature range of 10 to 70 ° C. The detergent formulation consists of {cleaning method; photographic carrier material; Rueckgewinnung; Reuse; Vormikroemulsionssysteme; emulsification; high-boiling oily components}

Description

Field of application of the invention

The invention relates to a process for the purification of the carrier material during its recovery from wastes of photographic films. The application can be made in the photochemical industry and in the treatment of unusable old films.

Characteristic of the known state of the art

In the recovery of the support material of photographic films, the cleaning process is an important step in the process. The cleaning must be designed in such a way that as far as possible a broad spectrum of dirt components of different composition can be eliminated.

Modern film materials contain water-insoluble, oily components in the emulsion layers and pigments, such as carbon black, in the backing layers. The water-insoluble, oily components are high-boiling organic substances, such as. For example, dibutyl phthalate, tricresyl phosphate, triphenyl, tributyl, Laurinsäurediethylamid dissolved in the main hydrophobic copper color. These water-insoluble, oily ingredients and pigments, which when removed

the emulsion or backing layers are exposed attract to the substrate due to their hydrophobic character. If these constituents are not removed from the carrier material, they cause disturbing effects, such as discoloration and cloudiness of the casting solutions and the films produced therefrom, when the carrier material is reused. Therefore, these "impurities" have to be removed before the carrier material is reused In order to achieve complete solubilization of the water-insoluble, oily components and dispersion of the pigments, high surfactant concentrations must be used for the cleaning process when commercially available (conventional) surfactants are used must be used to improve the effect of surfactant combinations, since the different amounts of dirt interact differently with the surfactants.

A disadvantage of such a system is the necessary, comparatively high surfactant concentration, since the liquor load in the cleaning process is likewise very high due to the ratio of film waste to liquor amount. In cleaning processes using conventional surfactants or surfactant combinations there is a strong foaming, the mixing of the comminuted film carrier material is reduced, the hydrodynamic behavior of the individual particles of the material to be processed is very limited and the viscosity of the entire wash liquor is increased, so that the applied mechanical Work is not effective and the surfactant effect is impaired in terms of cleaning of the substrate and solubilization of the dirt to be removed. As a result, the cleaning effect decreases very much.

In DE-OS 1,422,813 a process for the removal of the adhesive layer of photographic polycarbonate films by using a dilute aqueous solution of surfactants and / or carboxylic acids, hydroxycarboxylic acids, sulfonic acids or derer: salts is described. Such a procedure is only possible if the binding forces of the adhesive layer to the carrier material are very low and the adhesive layer contains organically synthetic polymers or copolymers. The removal of water-insoluble, oily components and pigments is not or only insufficiently possible with these aqueous solutions. When anionic surfactants are used, it is necessary to work with relatively high feed conversions when an effect is to be achieved, whereby the recovery cost of the carrier material greatly increases and the overall process becomes uneconomical. When nonionic surfactants are added to the washing process, the pigments are only removed inadequately. In addition, a high surfactant use concentration is also to be expected here.

DD-PS 289.635 describes a process in which high-boiling solvents and the hydrophobic agents contained therein are obtained by a washing process with an aqueous, softened solution of 0.5 to 10 g / l anionic and / or nonionic terside and 0.5 to 5g / l of oxidizing agent are removed. At the same time residues of the adhesive layer are removed. In the processing of highly cured film materials to remove the gelatin layers of the Trägermateiial the wash liquor additionally mild surface attack agents, such as dihydric phenols and / or lower alcohols rugesetzt. By using conventional surfactants or surfactant blends and softened water, this washing process is very costly. The removal of water-insoluble, oily components and pigments is hampered by juxtaposed, shredded film waste in the wash liquor, which extends the washing time to remove these impurities and / or increased kinetic energy of the reduced film waste in the wash liquor is required, which is also unfavorable to the Overall process affects.

Object of the invention

The aim of the invention is to develop a cost-effective and economically acceptable method for cleaning the carrier material during its recovery from waste photographic films, so that this carrier material can be used again as a high-quality raw material for Filmhurstellung.

Explanation of the essence of the invention

The object of the invention is to develop a process for complete and cost-effective removal of water-insoluble, oily components and pigments from the support material of photographic films in an energetically advantageous process control.

According to the invention, the lifts are achieved by separating the liquid phase after removal of the photographic layers and the backing layers in a known manner and subsequent rinsing processes and at least one washing process in water with the addition of a detergent formulation having a pH of 9 to 10, consisting out

From 5 to 20% by weight of a nonionic surfactant. Selected from the group of polyoxyethylene adducts,

From 5 to 20% by weight of an anionic surfactant selected from the group of sulfonates,

1.5 to 5% by weight of dimethylaminomethane bisphosphonic acid,

10 to 20% by weight of a lower n- or iso-alcohol and

- water up to a total of 100% by weight

(wherein the ReinigungsmittefformulierL-.ig is adjusted to a pH of 9 to 10 with technical 33% NaOH) and with the addition of an organic solvent in the temperature range of 10 to 7O ⁰ C performed. The composition of the detergent formulation is designed so that in this system can be spoken of a Vormikroemulsionssystem. Such systems are capable of incorporating high boiling organic components into the system at the interface. These pre-microemulsion systems act in principle like a microemulsion. You can incorporate organic substances with energy gain in their structure and on the other disperse the pigment dirt. As nonionic Tsnsid polyglycol ethers having 5 to 20 ethylene oxide units of alkylphenols having 8 to 14 carbon atoms in the side chain, of fatty alcohols having 10 to 16 carbon atoms and technical fatty alcohol mixtures, by selective reduction of fatty acid mixtures with a high content of unsaturated Acids were prepared to obtain the double bond and have an average of 16 to 18 L atoms used. As anionic surfactant Alkyiarylsulfonsäure, alkanesulfonic acid or its salts is used.

It has surprisingly been found that the addition of an organic solvent, for example xylene, to the premikroemulsion system leads to controllable foaming, to a decrease in the viscosity of the entire wash liquor and to avoid sticking together of the shredded film waste. As a result, the hydrodynamic conditions in the wash liquor are such that the favorable cleaning effect of the premix emulsion system is enhanced by the mechanical movement of the shredded film waste in the wash liquor. As further organic solvents, for example, cumene, dodecane, hexadecane or even spindle oil and mixtures of these substances can be used. The washing process in water with the addition of the detergent formulation and the organic solvent is carried out in a temperature range of 30 to 60 ⁰ C, preferably 4O ⁰ C. The cleaning time is depending on the degree of contamination of the carrier material between 0.5 to 2 hours. The ratio 1: 2.3 to 1: 4 has proven to be the most favorable mass ratio of film wastes to wash liquor, the concentration of the cleaning agent formulation preferably being δ to 10 ml / l washing water and the amount of the organic solvent being 0.7 to 1.4 ml / l washing water ,

The detergent formulation may be added to the wash tank prior to, during, or after the supply of wash water while the organic solvent is added shortly before the start of the wash process. However, with less movement of the shredded film wastes in the wash liquor, it may be desirable to mix the detergent formulation and the organic solvent with each other prior to being added to the wash tank. After the washing process with the addition of the cleaning agent formulation and the organic solvent, the removal of the adhesive layers takes place in a known manner, for example by adding a gelatin-degrading ferment or an oxidizing agent to the washing water. However, it is also possible to carry out the removal of the water-insoluble, oily components and pigments and the adhesive layers in a common wash liquor by adding a gelatin-degrading ferment or an oxidizing agent to the water in addition to the detergent formulation and the organic solvent. The support material of photographic films treated by the process according to the invention is obtained completely pure after removal of the adhesive layers and drying, and can be directly recycled for use in the production of support material for photographic films. The process according to the invention for recovering the support material of photographic films comprises the following stages:

- Shredding the coated waste from unusable photographic films in a known manner into a cutlet of approximately uniform size;

- Transporting the present heap in a washing device;

- Washing the film chips with water in the ratio of film chips to wash liquor 1: 2.3 to 1: 4 with the addition of a ferment, such as protease, until complete removal of the photographic layers;

- optionally removing the backing layers in a known manner by adjusting the pH of the wash liquor to 10 to 11;

- draining the wash liquor and rinsing at least once;

- supplying the wash water to the film chips and adding Jer detergent formulation;

- Addition of the organic solvent to the wash liquor;

- Washing at 30 to 60 ⁰ C;

- draining the wash liquor and rinsing at least once;

- Washing the film chips with water in a known manner with the addition of a gelatin-degrading ferment or an oxidizing agent until the complete removal of the adhesive layers;

- drain the wash solution and rinse at least once;

- mechanical dewatering of the film shreds and

- Thermal drying of the film shreds.

The advantages of the method according to the invention are the good universal cleaning action of the detergent formulation over water-insoluble, oily components and pigments and the use of small amounts of surfactant, so that the cleaning process can be carried out inexpensively. The addition of an organic solvent such as xylene, the juxtaposition of the shredded waste film, which inhibits the cleaning action is prevented, avoided, so that the dried support material can be recovered completely pure.

Another advantage is that the cleaning process can be performed regardless of the hardness of the washing water used. A high iron content in the water does not interfere with the cleaning also. In addition to the removal of the water-insoluble, oily components and pigments and the adventitious introduced into the washing process impurities are detected. The pH of the wash liquor for removing the water-insoluble, oily components and the pigments is about 7, with the use of conventional surfactants or surfactant combinations must be worked for a sufficient cleaning effect in the strong alkaline range.

Exemplary embodiments example 1

1000kg of shredded photographic film was placed in a 4.5m ³ capacity POhr container. The removal of the photographic layers was carried out in 3.5 m ³ of water at 4O ⁰ C with the addition of a proteolytic

Enzyme until reaching a proteolytic activity in the wash liquor of 40000 Kunitz units. By means of a

circulating stirrer, the film shreds were held in suspense. After a 3 hour wash, the photographic emulsion layers were completely removed. By adding 3.5 kg of sodium carbonate, a pH of 11 of the wash liquor was adjusted. After a washing time of 0.5 hours, the sooty backing layer was removed. After draining the wash liquor, the film pieces were rinsed three times with fresh water. The film schnitzel had a greasy, matte finish

Surface slightly stained brown. The adhesive layers were removed in 3.5 m ^{3 of} water at 40 ° C with the addition of a proteolytic enzyme until reaching

a proteolytic activity of 40000 Kunitz units in the wash liquor. After a washing time of 6 hours and a

Rinsing with fresh water five times, the film shreds had a greasy, matte surface that was lightly browned. The film chips thus treated were not suitable for re-use for producing a support material for photographic films.

Example 2

From 1,000 kg of shredded waste film, the photographic layers and the sooty back layer were removed as in Example 1. After rinsing the film pieces three times, they had a greasy, dull surface that was slightly brown in color. After rinsing, the film shavings These were 3.5 m ³ of water at 40 ⁰ C with the addition of 35 liters ReinlgHfigsmittelformullerung consisting of:

7.5 Gew.rAnteile an oxet'.iylierten fatty alcohol mixture of the chain length C-9 to C-15 with average EO content of

10 units or of a nonylphenyl polyoxyethylenesulfon EO units, 10 parts by weight of an alkanesulfonate (C-9 to C-15 alkyl chain mixture), 4.5 parts by weight Dimethylaminomethanbisphosphonsäure, 20 parts by weight of ethanol, 58 wt. Shares of water,

(The pH of this formulation was adjusted to 9.6 with technical grade caustic soda.) And 51 xylene. During the washing process, wash liquor samples were taken regularly and the extinction of the wash liquor was measured against distilled water. After a washing time of 1.75 hours, a break point of the curve appeared in the extinction-time diagram. At this washing time, the washing process was stopped and after draining the wash liquor, the film pieces were rinsed three times with fresh water. The film schnitzel had a shiny surface. Subsequently, the Fntfernen of the adhesive layers of the support material was carried out in 3.5 m ³ of water at 40 ⁰ C as in Example 1. The adhesive layers were removed by a washing period of 3 hours to fully from the support material. After drying, the film chips had a shiny, shiny surface.

Example 3,

1000 kg of shredded film waste were treated analogously to Example 2, but without the addition of xylene in the treatment step for removing the water-insoluble, oily components and pigments. After drying, the film chips visually had a shiny, shiny surface.

Examples 4-8

65kg of shredded photographic film was placed in a 3001 stirred tank. The photographic emulsion layers, the carbon black-containing backing layer and the adhesive layers were removed in each case in 2001 at 40 ^° C. analogously to Example 2. The proteolytic activity of the wash liquor to remove the gelatin layers was set to 2,300 Kunitz units in each case. To remove the carbon black-containing backing layer from the film waste, the pH 11 in the wash liquor was adjusted by adding 0.2 kg of sodium carbonate. After removing the sooty backcoat and rinsing the film chips three times, the film pieces were washed with water for 2 hours in 2001 with addition of a detergent formulation having the composition of Example 2, with the organic solvent addition and wash temperature being varied as follows for this washing process:

Example 4: 0.2 IDodecanbe! 20 ° C

Examples: 0.31 cumene at 30 ° C

Examples: 0.181 Hexadecanbei6O ⁰ C

Example 7: 0.11 spindle oil at 50 ° C

Examples: 0.121 xylene and 0.081 spindle oil bet 4O ⁰ C

After removing the adhesive layers, rinsing the film chips five times with fresh water and drying, the film pieces each visually had a bright, glossy surface.

Example 9

Casting solutions were prepared from the film chips treated and dried according to Examples 1 to 8. For this purpose, in each case 70 g of film chips were dissolved in 48 ml of methanol and 211 ml of methylene chloride. Of these casting solutions were in the universal colorimeter model UK VII by Dr. med. B. Long measured the extinctions. As a comparison solution was used a casting solution, which was prepared from primary cellulose triacetate granules. Dirty casting solutions lead to a light absorption and thus to correspondingly high Ext nktionswerten, wherein by means of the casting solution of primary cellulose triacetate granules a light absorption of 0% or an absorbance value of 0, located with the device located in the darkening device a light absorption of 100% or an Extionktionswert was set by 2.0. The layer thickness of the cuvettes used was 30 mm. The measurement of extinctions gave the values shown in Table 4.

Table 1: Extinctions of the casting solutions from the treated according to Example 1 to 8 film waste

Film waste, treated extinction of

according to Example 1 to 8 casting solution

Example 1 (without RMF, 40 ° C) 0.38

Example ?, (with RMF and xyiene; 40 "C) 0.01

Example 3 (mitRMFohne xylene; 4O ⁰ C) 0.07

Example 4 (with RMF and Dodec at 20 ° C) 0.03

Example 5 (u with RMF cumene;. 3O ⁰ C) 0.01

Example 6 (with RMF and Hexaccan, 6O ⁰ C) 0.03

EXAMPLE 7 (. RMFu with spindle oil; 5O ⁰ C) 0.05

Example 8 (with RMFu xylene + spindle oil; 4O ⁰ C) 0.02

RMF: detergent formulation

Investigations on the influence of the extinction of casting solutions on the transparency of different photographic films have shown that wash solutions of washed waste film with an extinction greater than 0.05 measured against casting solutions of cellulose triacetate primary granules are not suitable for producing a support material for photographic films.

Claims (11)

1. A process for the purification of the carrier material in its recovery from waste photographic films by removing the photographic layers and backing layers in a known manner, rinsing and drying, characterized in that separating the liquid phase after removing the photographic layers and the backing layers and subsequent rinsing processes at least one washing process in water with the addition of a liquid cleaning agent formulation with a pH of 9 to 10, consisting of - 5 to 20wt .-% of a nonionic surfactant selected from the group r clv polyoxyethylene adducts, From 5 to 20% by weight of an anionic surfactant selected from the group of sulfonates, 1.5 to 5% by weight of dimethylaminomethane bisphosphonic acid, 10 to 20% by weight of a lower n- or iso-alcohol and - water up to a total of 100% by weight (Wherein the detergent formulation with technical 33% sodium hydroxide solution is adjusted to a pH of 9 to 10), and with the addition of an organic solvent within the temperature range of 10 to 70 ⁰ C performed. 2. A process for purification according to claim 1, characterized in that as a nonionic surfactant polyglycol ethers having 5 to 20 ethylene oxide units of alkylene phenols having 8 to 14 carbon atoms in the side chain, of fatty alcohols having 10 to 16 carbon atoms and technical fatty alcohol mixtures , which were prepared by selective reduction of fatty acid mixtures with a high proportion of unsaturated acids to give the double bond and have an average of 16 to 18 carbon atoms, are used. 3. A process for purification according to claim 1 and 2, characterized in that are used as the anionic surfactant Alkylarylsulfonsäuren or alkanesulfonic acids or their salts. 4. A process for purification according to claim 1 to 3, characterized in that the concentration of the Reinigungsmittelformuliei ung 3 to 15ml / l of washing water. 5. A process for purification according to claim 1 to 4, characterized in that the concentration of the detergent formulation is preferably 10ml / l wash water. 6. A process for purification according to claim 1, characterized in that are used as the organic solvent xylene, cumene, dodecane, hexadecane, spindle oil or mixtures thereof. 7. A process for the purification according to claim 1 and 6, characterized in that xylene is preferably used as the organic solvent. 8. A method of purification according to claim 1,6 and 7, characterized in that the concentration of the organic solvent is 0.5 to 3 ml / l of washing water. 9. A method of purification according to claim 1, 6,7 and 8, characterized in that the concentration of the organic solvent is preferably 1.4 ml / l of washing water. 10. A process for purification according to claim 1 to 8, characterized in that the washing process is carried out in water with the addition of the detergent formulation and with the addition of the organic Lösungsmi.tdls in a temperature range of 30 to 60 ⁰ C. 11. A process for purification according to claim 1 to 10, characterized in that the washing process is preferably carried out at 40 ⁰ C.