JP2604262B2 - Collection method of photographic film support - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for recovering a photographic film support. In particular, the present invention relates to a support comprising a cellulose triacetate film, wherein an undercoat layer containing nitrocellulose and gelatin is provided on the surface of the support. The present invention relates to a method for recovering a support from a photographic film formed in a reusable state.

[Technical Background of the Invention] A photographic light-sensitive material is generally formed by forming a photographic layer such as an undercoat layer, a back layer, and a photosensitive layer, an intermediate layer, and a surface protective layer on a support made of a plastic film.

In the present specification, the term "photographic film" means not only a photosensitive material having a photographic layer, but also a so-called "photographic base" (support + undercoat layer) before the photographic layer is applied. I do.

Generally, the support is composed of a cellulose triacetate film, but such a support usually has a bound acetic acid amount of 60 to
62% cellulose acetate is dissolved together with a plasticizer in, for example, a mixed solvent of methylene chloride and methyl alcohol to form a dope. The dope is filtered, defoamed, and then continuously moved such as a metal drum or an endless band. It is manufactured by a casting film forming method in which a solvent is cast on a support to be evaporated and a solvent is evaporated (for example, see Japanese Patent Publication No. 45-9074).

An undercoat layer is provided on the surface of the support to enhance the adhesion between the support and a photographic layer such as a photosensitive layer. In addition, a back layer is generally provided on the surface opposite to the surface on which the photographic layer is provided, for antistatic, curling adjustment, slipperiness, antihalation, and the like. The back layer may be provided directly on the support or may be provided on the support via an undercoat layer.

The undercoat layer and the back layer provided in contact with the support are formed into a solution using a liquid having a swelling property or a partial solubility with respect to the support as a solvent, and is applied to the surface of the support.

The layer formed by application in such a manner partially penetrates into the inside of the support, and is firmly connected to the support by an anchoring phenomenon.

Since the photographic film does not undergo any change in the support even after exposure and development, it is resource-saving to collect only the support from used photographic film and reuse it as a raw material for new photographic film. It is extremely important from the point of view.

Generally, the following methods are available for recovering the support from a photographic film.

One of them is a photographic film that is discharged as a waste from the photosensitive material manufacturing process or processing process, before or after the application of the photographic layer, or a photosensitive material such as a hospital, a movie company, a broadcasting station, and a developing laboratory. Accumulates used film discharged from the user, turns such a photographic film into chips of 1 to several cm square or less, immerses the chips in an aqueous solution containing a protease, The photographic layer such as a layer and the gelatin-containing layer such as a subbing layer are removed. Thereafter, the chips are washed with water, and the dyed chips are extracted and removed with an acetone-methanol mixed solvent or the like. Then, the chip is further washed with water and dried, and the reusable chip obtained is used for producing a photographic film support or for other uses.

Another method is a method described in JP-A-53-15829, which uses a cellulose triacetate film as a support and has a molecular weight of 5,000 or more in its back layer and / or undercoat layer. In a method of recovering a cellulose triacetate support from a photographic film containing a synthetic polymer compound, an organic solvent solution containing at least one organic solvent which previously dissolves or swells the cellulose triacetate film, or an inorganic solvent A method for recovering a photographic film, comprising performing a pretreatment with a solution containing an acid. This method requires a high quality requirement due to its back layer and / or
Alternatively, it is an effective method for recovering a cellulose triacetate support from a photographic film in which a synthetic polymer compound having a molecular weight of 5,000 or more is added to an undercoat layer.

On the other hand, in order to firmly bind the undercoat layer to the surface of a support made of a cellulose triacetate film, it has long been practiced to include nitrocellulose (NC) in an undercoat layer containing gelatin. It is extremely difficult to completely remove the nitrocellulose from the support according to the known method for recovering a support from a photographic film, and it is necessary to recover a regenerated chip of a cellulose triacetate film having excellent quality. Is difficult.

That is, quality inspection of a regenerated chip of a cellulose triacetate film is performed, for example, by using methylene chloride-methanol (9:
The recycled chip is dissolved in the mixed solvent of 1) to make a dope, and the transmittance and the presence of insoluble matter of the dope are evaluated by optically examining. The nitrocellulose is contained in the recycled chip. Then, the transmittance of the dope decreases and the amount of insoluble matter increases. Therefore, such a reclaimed chip can be re-used as a photographic support due to drawbacks such as causing trouble when the photographic support is manufactured from now on or a decrease in the quality of the manufactured photographic support. Can not.

Therefore, in order to completely remove nitrocellulose, the low-quality regenerated chip containing nitrocellulose must be subjected to an extraction removal treatment using an acetone-methanol mixed solvent or the like again. However, there is a risk of explosion due to the use of the acetone-methanol mixed solvent.
In practice, most of the low-quality regenerated chips containing nitrocellulose must be incinerated because of an increase in cost due to distillation and purification of the methanol mixed solvent.

[Object of the Invention] An object of the present invention is to provide a support comprising a cellulose triacetate film, wherein a nitrocellulose is substantially contained from a photographic film in which a subbing layer containing nitrocellulose and gelatin is formed. Another object of the present invention is to provide a method for easily and safely recovering a recycled chip of a support made of a cellulose triacetate film of excellent quality which can be reused as a photographic support.

[Summary of the Invention] The present invention provides a method for recovering a support comprising a cellulose triacetate film from a photographic film in which an undercoat layer containing nitrocellulose and gelatin is formed on the surface of the support. A first step of pretreating the photographic film with an aqueous solution containing a surfactant, and removing the undercoat layer from the support by treating the photographic film pretreated in the first step with an aqueous solution containing a protease; A method for recovering a photographic film support, which comprises a second step.

 The preferred embodiments of the present invention are as follows.

1) The method for recovering a photographic film support described above, wherein the surfactant used in the first step is a nonionic surfactant, a cationic surfactant, or an anionic surfactant.

2) The method for recovering a photographic film support described above, wherein the surfactant used in the first step is a polyethylene glycol ether-based nonionic surfactant.

3) The method for recovering a photographic film support described above, wherein the first step is performed using an alkaline aqueous solution containing a surfactant.

4) carrying out the first step at a temperature of 30 to 60 ° C. until the photosensitive layer, intermediate layer, undercoat layer, back layer and the like of the photographic film swell or soften. Collection method.

5) The method for recovering a photographic film support according to the above, wherein in the second step, the solution is treated with an aqueous solution containing a protease and an anionic surfactant.

6) The method for recovering a photographic film support as described above, wherein the anionic surfactant is a higher alcohol sulfate salt.

7) The method for recovering a photographic film support described above, wherein the support obtained in the second step is bleached by treating with a hydrogen peroxide solution.

[Detailed Description of the Invention] A photographic film to which the recovery method of the present invention is applied is one in which at least an undercoat layer is formed on the surface of a support made of a cellulose triacetate film, and at least nitrocellulose is formed on the undercoat layer. And gelatin. Such a photographic film is discharged in large quantities from the photosensitive material production / processing step and the user as described above.

The nitrocellulose is known per se, usually 10
It has a nitrogen content of about 14%. The undercoat layer usually contains nitrocellulose in an amount of about 0.01 to 2.0 g / m ² and gelatin in an amount of about 0.01 to 2.0 g / m ² .

In the present invention, before performing the process of the first step, the photographic film collected and accumulated as described above is formed into chips, and the length of the side is several cm or less, preferably a chip having a size of about 1 cm to about 4 cm. To

In the first step of the present invention, the photographic film chip is pretreated with an aqueous solution containing a surfactant.

As the surfactant, any surfactant known per se, such as a nonionic surfactant, a cationic surfactant or an anionic surfactant, can be used.
In particular, a nonionic surfactant is preferable. As the nonionic surfactant, in particular, polyethylene glycol ether-based surfactants, for example, surfactants such as polyethylene glycol ether of higher alcohol, polyethylene glycol ether of alkylphenol, and polyethylene glycol ether of sorbitan ester are preferable. The surfactant is preferably a primary to tertiary amine-based or quaternary ammonium-based surfactant, and the anionic surfactant is preferably a surfactant as exemplified later. The concentration of the surfactant in the aqueous solution containing the surfactant used in the first step may be a commonly used concentration, for example,
The concentration may be from 0.1 to 5% by weight.

The aqueous solution containing a surfactant used in the first step is preferably made into an alkaline aqueous solution by adding a suitable alkalizing agent. Specific examples of the alkalizing agent include, for example, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, and sodium hydroxide. The concentration of the alkalizing agent varies depending on the type of the surfactant used, the composition of the photographic film to be processed, and the like.
It is preferred that the concentration be such that

The pretreatment of the first step is performed at room temperature to about 70 ° C, particularly, at 30 to 60 ° C.
It is generally preferable to carry out the stirring at a temperature of 10 to 100 minutes until the photosensitive layer, intermediate layer, undercoat layer, back layer and the like of the photographic film swell or soften. After processing in the first step,
Usually, it is washed with water for 1 to 30 minutes to remove the treatment liquid of the first step.

In the second step of the present invention, the photographic film pretreated in the first step is treated with an aqueous solution containing a protease, and the undercoat layer together with the photosensitive layer is removed from the support.

The protease may be any protease that can degrade gelatin. For example, proteases of animal origin (eg, pepsin, trypsin, etc.), plant origin (eg, papain, chymopapain, bromelain, ficin, etc.), and microbial origin [eg, actinomycetes protease (pronase)] can be used. it can. The treatment solution in the second step is preferably adjusted to a pH value at which the protease used is optimal for decomposing gelatin. In general, the concentration of the protease in the treatment solution is preferably 0.01 to 2.0% by weight.

The treatment liquid used in the second step of the present invention may contain an anionic surfactant together with the protease. As the anionic surfactant, any anionic surfactant known per se can be used. Particularly, higher alcohol sulfates, sodium alkylbenzene sulfonates, and sulfates of polyoxyethylene adducts It is preferably a salt or the like. The concentration of the anionic surfactant may be a commonly used concentration, for example, 0.1 to 5
It may be at a concentration of% by weight.

The treatment in the second step is generally carried out at a temperature of room temperature to about 70 ° C., particularly 30 to 60 ° C., until the undercoat layer containing nitrocellulose and gelatin together with the photosensitive layer is removed from the support.
It is preferable to carry out the stirring for ~ 200 minutes. After the treatment in the second step, it is usually washed with water for 1 to 30 minutes to remove the treatment liquid in the second step.

When the support recovered by the recovery method of the present invention is a colored support, the support from which the undercoat layer obtained by the treatment in the second step of the present invention is removed is then subjected to peroxide treatment. It is preferable to bleach by treating with hydrogen water.

The concentration of hydrogen peroxide in the hydrogen peroxide solution is preferably 1 to 20% by weight. The bleaching conditions vary depending on the concentration of the hydrogen peroxide solution, the degree of coloration of the support obtained from the second step, and the like, but are generally from room temperature to 90 ° C, particularly from 70 to 90 ° C.
At a temperature of about 30 to about 30 minutes until the support is sufficiently bleached.
It is preferable to carry out with stirring for 150 minutes. After bleaching
The support is thoroughly washed, usually for 1 to 30 minutes.

The support chip made of cellulose triacetate recovered according to the present invention has a high transmittance when used as a dope for producing a support for a photographic film, and has a high transmittance. It can be reused to produce a photographic film support in the same manner as a suitable cellulose triacetate.

 Next, the embodiment will be described more specifically with reference to the embodiment.

[Example 1] A projected color positive film (containing nitrocellulose and gelatin and having an undercoat layer of 1 µm thickness) was prepared.
A chip having a size of 3 cm square was formed, and the following treatment was performed using 1300 g of the chip.

Incidentally, the nitrocellulose in the above film, water 200m
l, a uniform solution prepared by mixing 700 ml of concentrated sulfuric acid and 3.7 g of diphenylamine was dropped on a film using a glass rod, and it was confirmed that the film had turned blue.

Further, the gelatin in the film was confirmed by immersing the chip of the film in a uniform liquid prepared by mixing 0.5 g of CI Basic Violet 3 (CI42555) with 1000 ml of water for 5 minutes, and developing a purple color. .

(First step) As a nonionic surfactant, polyethylene glycol ether of a higher alcohol (trade name "Emulgen 106",
Kao Corporation 30g and sodium carbonate 20g and water 3000ml
To prepare a treatment solution.

The chip is immersed in this treatment solution, and maintained at 45 ° C. for 45 minutes.
Stirring was continued for a minute for pretreatment.

The pretreated chip was washed with water in water at 20 to 25 ° C. with stirring for 20 minutes.

(Second step) Proteolytic enzyme (Pronase E: manufactured by Kaken Chemical Co., Ltd.)
2g and anionic surfactant as higher alcohol sulfuric acid ester sodium salt (trade name "Monogen" (C ₁₂ H ₂₅ is the main component), Dai-ichi Kogyo Seiyaku Co., Ltd.) and 20g is dissolved in water 3000 ml, the treatment liquid Was prepared.

The chip obtained in the first step was immersed in the treatment liquid, and the mixture was treated at 55 ° C. for 40 minutes while stirring.

The treated chip was washed with water in water at 20 to 25 ° C. with stirring for 20 minutes.

(Bleaching Treatment) (Third Step) A bleaching treatment solution was prepared by mixing 300 ml of 35% hydrogen peroxide solution with 3000 ml of water.

The chip obtained in the second step was immersed in this treatment liquid, and the mixture was kept at 80 ° C. and stirred for 90 minutes to be treated.

The treated chip was washed with water in water at 20 to 25 ° C with stirring for 30 minutes.

The washed chip was dried at 80 ° C. for 60 minutes to obtain a collected chip.

The chips recovered as described above were dissolved in a mixed solvent of methylene chloride / methanol (9: 1) to prepare a dope having a concentration of 15%. The transmittance of this dope was measured using a transmittance meter (a photoelectric colorimeter manufactured by Kotaki Seisakusho KK), and the presence or absence of insoluble matter was visually observed.
Table 1 shows the results.

[Example 2] In the second step of Example 1, except that the anionic surfactant was not used, and the immersion of the chip and the stirring time were changed to 120 minutes, the same procedure as in Example 1 was performed. The chip was collected.

Example 1 about the chip collected as described above
In the same manner as in 1, the transmittance was measured, and the presence or absence of insoluble matter was visually observed. Table 1 shows the results.

[Comparative Example 1] 1300 g of the same chip as that used in Example 1 was immersed in a treatment solution in which 2 g of protease (pronase E: manufactured by Kaken Chemical Co., Ltd.) was dissolved in 3000 ml of water, and maintained at 55 ° C. 1
Stirring was continued for hours.

The treated chip was washed with water while stirring in water at 20 to 25 ° C. for 20 minutes, and dried.

The resulting chips were treated with a mixed solvent of methanol / acetone (7/3) using a Soxhlet extractor for 30 minutes to extract the dye.

The obtained chip was washed with water while stirring in water at 20 to 25 ° C. for 10 minutes, and dried.

Example 1 about the chip collected as described above
In the same manner as in 1, the transmittance was measured, and the presence or absence of insoluble matter was visually observed. Table 1 shows the results.

Comparative Example 2 1300 g of the same chip as that used in Example 1 was immersed in 3000 ml of a mixed solvent of methanol / acetone (7/3) and left at about 25 ° C. for 10 hours.

Thereafter, the chip was washed with 3000 ml of water for 10 minutes and dried.

Example 1 about the chip collected as described above
The transmittance was measured in the same manner as described above, and the presence or absence of insoluble matter was visually observed. Table 1 shows the results.

[Reference Example 1] The chip obtained in Comparative Example 1 was further subjected to an extraction treatment using 3000 ml of a mixed solvent of methanol / acetone (7/3).
Processed repeatedly.

Thereafter, the chip was washed with 3000 ml of water for 10 minutes and dried.

Example 1 about the chip collected as described above
In the same manner as in 1, the transmittance was measured, and the presence or absence of insoluble matter was visually observed. Table 1 shows the results.

As is clear from the results in Table 1, when the photographic film containing nitrocellulose was used for the undercoat layer as the object to be processed, the chips recovered in Examples 1 and 2 had high transmittance of the dope. Since there is no insoluble matter, it can be reused to produce a photographic film support in the same manner as the novel cellulose triacetate. It was low turbid and insoluble (gel), and could not be used as a raw material for producing a photographic film support.

In order for the chip obtained in the comparative example to be reusable similarly to the chip obtained in the example, reference example 1
It was necessary to repeat the extraction and purification treatment with a methanol / acetone mixed solvent as shown in FIG.

[Effects of the Invention] The method for recovering a photographic film support of the present invention comprises the steps of substantially converting a photographic film in which an undercoat layer containing nitrocellulose and gelatin is formed on the surface of a support made of a cellulose triacetate film. A recycled chip of a support made of a cellulose triacetate film of excellent quality that does not contain nitrocellulose and can be reused as a photographic support,
A remarkably excellent effect that it can be collected easily, safely and at low cost can be obtained.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kensaku Nakamura 392 Hiromachi, Minamiashigara-shi, Kanagawa Prefecture Inside Panak Kogyo Co., Ltd. References JP-A-62-160451 (JP, A) JP-A-53-15829 (JP, A) JP-A-52-97738 (JP, A) JP-A-50-80371 (JP, A) JP-A Sho 52 -138131 (JP, A) US Patent 2,698,235 (US, A)

Claims (3)

(57) [Claims] 1. A method for recovering a support comprising a cellulose triacetate film from a photographic film having an undercoat layer containing nitrocellulose and gelatin formed on the surface of the support, comprising: A first step of pretreating with an aqueous solution containing an activator, and a second step of treating the photographic film pretreated in the first step with an aqueous solution containing a protease to remove the undercoat layer from the support A method for recovering a photographic film support, comprising: 2. The method for recovering a photographic film support according to claim 1, wherein in the second step, a treatment is carried out with an aqueous solution containing a protease and an anionic surfactant. 3. The method according to claim 1, further comprising a first step and a second step, and a third step of treating the support obtained in the second step with an aqueous hydrogen peroxide solution to bleach it. The method for recovering a photographic film support according to claim 1.