JPH0687159B2 - Method for producing developer absorbing base material for photographic film, base material and self-processing photographic film unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is used for a developer absorbing base material for a photographic film, which captures and absorbs a photographic developing solution, and particularly used for a self-processing photographic film (instant photographic film) unit, The present invention relates to a method for producing a developer-absorbing non-woven fabric substrate for collecting and capturing an excessive amount of a treatment liquid generated during development processing of the unit, the substrate, and a self-processing photographic film unit.

(Prior art and its problems) As an example of a developer absorbing material that captures and absorbs a photographic developing solution, it is used by being built in a self-processing photographic film unit generally called an instant photographic film and used during development processing. There is a trap material that has a function of immediately collecting and trapping the generated alkaline developing solution, and then neutralizing it.

The above self-processing photographic film unit is, for example, Japanese Patent Publication Sho 61
Although there are differences in the layer structure and the development processing method depending on the type as shown in Japanese Patent Publication No. -50305, a first sheet member (1) including an image receiving layer as shown in FIGS. The second sheet member (2) mainly has two flexible sheets for assisting the uniform distribution of the developing solution as a layer having a predetermined thickness. A container means (3) capable of releasing the treatment liquid by rupturing a predetermined portion by pressing a pair of rollers, and capturing / neutralizing an excess of the treatment liquid released / dispersed from the container means (3). It is configured with possible trapping means (4). The trap material is required to have a function of instantaneously completely capturing / absorbing / neutralizing a surplus processing solution having a high alkali / viscosity, and after the absorption, even if an external pressure is applied to the trap means, the processing solution remains Liquid retention is also required so that the liquid does not flow back to the image surface or leak to the outside.

Conventionally, as the trap material, a sheet-shaped material such as cloth, gauze, lace, non-woven fabric, glass wool, absorbent paper, filtration, felt, or a fine mesh plastic net, or a composite material made of a combination thereof is used. A material obtained by impregnating an acidic material having an alkali neutralizing function on a base material having flexibility, air permeability and surplus treatment liquid trapping property is used.

However, the base material used for the conventional trapping material is, as described above, a sheet material such as cloth, gauze, lace, non-woven fabric, filter paper, felt, a plastic net of mesh, or a plurality of processes in which these are laminated and bonded together. Since it is manufactured more, there is a problem that the cost becomes high and labor is required, and the density is fixed depending on the material used. In addition, no one with functions such as instant capture of surplus treatment liquid and liquid retention against external pressure was found, and it was thin and excellent in instantaneous capture of treatment liquid, and did not backflow against external pressure or leak outside. At present, there is a demand for the development of a developer absorbing base material having an excellent liquid retention property.

(Means for Solving the Problems) In the present invention, in view of the above situation, as a result of intensive studies and developments, as a result, an excessive development processing solution having a high viscosity is promptly collected and collected, and after absorbing the external pressure. A method for producing a developer absorbing base material for a photographic film, which is particularly useful as a base material for a trap portion for a self-processing photographic film, which is excellent in liquid retention without backflow and external leakage, the base material, and a self-processing photographic film unit Is provided.

That is, at least a binder fiber having self-adhesiveness is used.
A heat-fusible non-woven fabric sheet containing 10 wt% or more of two dense and coarse layers having a fiber layer density of 0.35 g / cm ³ or more on one surface side and a fiber layer density of 0.25 g / cm ³ or less on the other surface side. Structure, or having a dense and dense structure in which the density gradually changes from one surface side to the other surface side (hereinafter, simply referred to as a coarse and dense two-layer structure including all of these), and the compressive load (50 g / cm ² ) on the nonwoven fabric sheet A non-woven sheet having a large void volume and a large compression hardness, which has a mechanical property of 0.20 g · cm / cm ² or less, and a compression elastic modulus showing a compression recovery property of 40% or more when giving It has been found that very suitable results are obtained when used in a self-processing photographic film unit as a developer absorbing substrate for a photographic film.

The above-mentioned compression mechanical characteristic value is measured by a compression tester (KES-F3) of the test system KES-F series designed and developed for the purpose of measuring the texture of the cloth, and the compression characteristic value of the sheet fiber product. Is generally used as a device for measuring.

The mechanical characteristic values of this device will be briefly described below.

The work of compression Wc (g · cm / cm ² ) is applied to the measurement sample placed on the sample support base at a constant speed of 0.02 mm / sec from above,
The compression work amount per unit area of the sample up to the compression load of 50 g / cm ² is shown (corresponding to the shaded area abca in Fig. 4). The smaller the value, the harder it is to compress and deform. .

The compression elastic modulus Rc (%) is as follows after the compression load reaches 50 g / cm ² .
It is calculated from the following formula from the compression recovery work amount Wc (corresponding to the dbcd portion of the black coating portion surface in FIG. 4) in the process of releasing the pressurization at a constant speed of 0.02 mm / sec.

Rc = Wc ′ / Wc × 100 (%) Rc represents compression recovery and compression elasticity, and the larger the value, the better the thickness recovery, and the smaller the permanent set with respect to the applied pressure.

The method for producing a developer absorbing base material for a photographic film, the base material and the self-processing photographic unit of the present invention will be described in more detail below by using the above mechanical property values.

In the constitution of the present invention, the heat-bonding nonwoven fabric sheet to which the binder fiber having self-adhesiveness is applied has a large amount of compressive deformation with respect to pressure because the binding point between the fibers is small when the mixing ratio of the binder fiber is small. Therefore, the compression work Wc becomes a large value. When a non-woven fabric sheet having a large amount of compressive deformation with respect to pressure is used as a developer absorbing base material as described above, compressive deformation easily occurs against external pressure, which causes backflow of absorbed processing liquid and external leakage, which is preferable. Therefore, the mixing ratio of the binder fiber is at least 10% by weight or more, preferably 50% by weight or more, particularly preferably 60 to 90%.
It has many mutual binding points between fibers obtained by mixing in wt%, and the compression work Wc is 0.20 g · cm / cm ² or less (preferably 0.0
It is preferable to use a non-woven fabric sheet having a high compression hardness of 5 to 0.20). Especially spread with a pressure roll of a predetermined pressure,
This compression work (compression hardness) is an important judgment factor for the function of surely capturing / holding the dispersed excess processing liquid in the trap material and preventing liquid leakage to the outside.

Further, a method of applying an external adhesive such as a binder is conceivable as a method of connecting the fibers to each other, but in the external binder applying method, a large amount of the binder is required to finish it into a predetermined compression hardness. As a result, the inter-fiber voids of the non-woven fabric sheet that serves as the developer absorbing base material are reduced, and the processing solution absorbency is reduced, which is not preferable. Further, it has been found that a non-woven sheet having a compressive elastic modulus Rc of 40% or more is suitable for satisfying this requirement as soon as it is required to completely recover the thickness against the compressive deformation from the outside. That is, this characteristic value is an important factor similar to the compression work Wc with respect to the required characteristic that the surplus processing liquid extruded by the pressure roll is retained in the trap base material without being squeezed out. In addition, the nonwoven fabric sheet having the compression characteristics as described above can obtain a developer absorbing base material for a photographic film having better performance by using fibers having high bulk and excellent impact resilience, preferably polyester fibers. .

Next, the instantaneous capturing property with respect to the high-viscosity processing liquid is basically obtained by applying a fiber sheet having a high porosity, but a material having the above-mentioned compression characteristics is required. Therefore, the fiber layer density on one surface side is 0.35 g / cm ³ or more,
On the other hand, it was found that a non-woven fabric sheet having a coarse and dense two-layer structure having a fiber layer density on the surface side of 0.25 g / cm ³ or less is preferable.

That is, the excess processing liquid spread and dispersed by the pressure roll is captured and absorbed from the low density layer side of the non-woven fabric sheet that serves as the developing and absorbing base material of the trap portion without being largely compressed and deformed by the pressure roll. Then, the non-woven fabric sheet is quickly filled and captured in the voids. At this time, since the other surface side of the non-woven sheet is densely filled with fibers, the absorbed treatment liquid does not penetrate into the high-density layer, is efficiently trapped inside the non-woven sheet, and leaks to the outside. Liquid can be prevented.

The fiber packing density is preferably 0.25 g / cm ³ or less, particularly preferably 0.20 g / cm ³ or less, in order to instantaneously capture and collect the high-viscosity processing liquid on the low density layer side. Is good. On the high-density layer side, 0.35 g / cm ³ or more is preferable because the absorbed high-viscosity processing liquid is difficult to penetrate. The weight ratio of the low density layer and the high density layer is not particularly limited, and a film-like thin layer may be formed as the high density layer.

Furthermore, the fineness is 1 to 20 to satisfy the above-mentioned required performance.
By appropriately mixing and using thick polyester fibers from relatively thin denier polyester fibers, a solid skeleton structure is formed by the thick denier polyester fibers,
It is possible to obtain a developer-absorbing base material for a photographic film, which is more excellent in compression hardness, compression elasticity, instant catching property of a processing liquid and its liquid retaining property. The polyester fibers may be of the same denier, and are not limited to these.

As the polyester fiber, high Young's modulus polyester, water-absorbent polyester, hollow polyester, various modified cross-section polyesters, etc. can be used.

The self-processing photographic film unit of the present invention is constructed using the trap material formed of the above-mentioned base material.
It is also applicable to a self-processing photographic unit other than the structure shown in FIGS.

Next, a preferred method for producing the developer absorbing base material for the photographic film will be described.

As described above, the developer absorbing base material for the photographic film, for example, the trap portion base material, is required to have a high void for promptly capturing and collecting the excess processing liquid, a compression hardness that does not cause compression deformation due to an external pressure, and a compression recovery property. . The non-woven fabric sheet having such performance is most preferably a heat-fusible non-woven fabric using a binder fiber having a self-adhesive ability. That is, since the fiber crossing points are surely adhered to each other, a desired compression hardness can be easily obtained, and a high porosity non-woven sheet can be obtained because no externally applied binder is contained.

Usually, the heat-fusible non-woven fabric sheet is subjected to thermocompression bonding treatment with a pair of calender rolls set at the same temperature in the upper and lower sides to obtain uniform front and back surfaces. This process has been devised and improved in order to impart porosity, compression hardness, and the ability to prevent external leakage of the treatment liquid.

That is, as shown in one example in FIGS. 1 and 2, a fibrous web (5) formed by a web forming machine containing at least 10% by weight or more, preferably 50% by weight or more of self-adhesive binder fibers as described above. ) Is a fixed non-woven fabric of the web and is provided with a large number of columnar holes in the cross-sectional direction, needle punching is performed by the needle punching machine (6),
Next, the needle punched non-woven fabric (7) is heated above the melting point of the binder fiber, preferably above the melting point by 10 ° C or more, and the upper roll (8) below the melting point of the binder fiber, preferably below 20 ° C above the melting point. Set lower roll (9)
By heat-pressing with a pair of calender rolls composed of the above, a nonwoven fabric sheet (10) having a coarse and dense two-layer structure with different fiber layer densities on the front and back can be obtained. The non-woven fabric sheet thus obtained, due to the temperature difference between the upper and lower sides of the pressure roll, the fiber density of one surface side is 0.35 g / cm ³ or more, the other surface side is 0.25 g / cm ³ or less dense and two-layer structure, or , Which has a coarse and dense structure in which the density gradually changes from one surface side to the other surface side, and has an instantaneous trapping property for the surplus treatment liquid and a penetration preventing property of the collection treatment liquid, but the fiber intersection of the low density layer side Since they are not sufficiently adhered, they lack the compression hardness against external pressure and cannot sufficiently satisfy the purposes of retaining the processing liquid and preventing external leakage. further,
The trap material obtained by impregnating the non-woven fabric sheet with an acid having an alkali neutralizing function is cut into 90 mm x 5 mm strips and incorporated into the trap unit. In order to eliminate the cause of problems such as the occurrence of trouble, calendering is followed by heat-pressing treatment, followed by heat treatment at a temperature not lower than the melting point of the binder fiber, preferably not lower than 10 ° C., without pressing, as shown in FIG. The fiber density on one surface side (13) is
High density of 0.35 g / cm ³ or more, low density of fiber layer on the other side (14) of 0.25 g / cm ³ or less, and mutual adhesion between fibers due to welding of heat-adhesive fibers. A developer absorbing base material (16) for a photographic film having good performance with a dense and dense two-layer structure having columnar holes (15) in the cross-sectional direction is obtained.

That is, by heat treatment under no pressure, a strong adhesive force is imparted to the nonwoven fabric sheet that maintains the dense and dense two-layer structure, excellent compression hardness is imparted, and at the same time, the problem of fiber loss due to the cutting treatment is solved. is there. As the heat treatment method under no pressure, a method of passing through a hot air circulation type hot air heat treatment machine (11) set to the melting point of the binder fiber or more, a heat roll set to the melting point or more (12) ) Means may be used such that the side surface of the low-density layer of the non-woven sheet is fusion-bonded and passed over the surface.

The present invention will be described in more detail based on the following examples.

Example 1 Core-sheath type binder fiber 4d × 51 mm 70%, which is a regular polyester having a core melting point of 250 ° C. and a low melting point polyester having a melting point of 130 ° C., regular polyester fiber
12d × 51mm The fiber mat, which is made of 30% mixed cotton and uniformly spread, is introduced into the needle punching machine, and the driving depth is 10m.
Needle punching is performed under the conditions of m and the number of punches is 100 p / cm ² to make a felt-like nonwoven fabric sheet, and the upper roll temperature is
It was introduced into a calender roll set to 150 ℃ and the lower roll temperature was set to 90 ℃, and then passed through a hot air circulation type heating furnace set to 150 ℃, and the fabric weight of 190g / cm ² and the front and back fiber density of 0.65mm were obtained. The developer absorbing base materials for photographic films having different coarse and dense two-layer structures were obtained. Next, on the developer absorbing base material, an epoxy curing agent "Arubadite (trademark) manufactured by Ciba Geigy" at 5 mol% based on polyacrylic acid "Jurimer (trademark) manufactured by Nippon Pure Chemical Co., Ltd." 5 mol%
Add NaOH and dilute it with methanol to make a solution with a polyacrylic acid concentration of 15%. Solid content of 50 g / cm
² was applied and then dried at 100 ° C. for 10 minutes, and this was used as a trap member for a self-processing photographic film unit. The same impregnation treatment was applied to the following examples and comparative examples to obtain trap members.

Example 2 A fiber mat formed in the same manner by using the same core-sheath type polyester binder fiber 4d × 51 mm 100% used in Example 1 was used in the same manner as in Example 1 to have a basis weight of 190 g / cm ² and a thickness of 0. .
A developer absorbing base material for a photographic film having a coarse and dense two-layer structure having different fiber densities on the front and back sides of 62 mm was obtained.

[Example 3] Core-sheath type binder fiber 6d × 51 mm 50% and hollow polyester fiber 6d × 75 mm 50% having a hollow cross section, which is a regular polyester having a melting point of 250 ° C. and a low melting point polyester having a melting point of 180 ° C. A fiber mat formed by uniformly opening and laminating mixed fibers with and is introduced into a needle punch processing machine,
After performing needle punching under the conditions of a driving depth of 9 mm and a punch count of 150 p / cm ² to make a felt-like non-woven fabric sheet, a calender roll set with an upper roll temperature of 205 ° C and a lower roll temperature of 150 ° C was set. After thermocompression bonding, the third hot roll (1
2) Heat treatment was carried out by passing the surface through contact to obtain a developer absorbing base material for a photographic film having a basis weight of 200 g / cm ² and a thickness of 0.70 mm and having different fiber densities on the front and back sides.

[Comparative Example 1] A nonwoven fabric sheet formed under the same conditions as in Example 1 was thermocompression-bonded with a calender roll set to have both upper and lower roll temperatures set to 140 ° C to obtain a nonwoven fabric sheet.

[Comparative Example 2] A non-woven sheet was formed in the same manner as in Example 1 until calender roll processing, and the heat treatment under no pressure was omitted to obtain a non-woven sheet.

[Comparative Example 3] Core-sheath type binder fiber 2d × 38 mm made of 6 nylon having a core melting point of 230 ° C. and copolymer nylon having a sheath melting point of 140 ° C.
The fiber mat made of 60% and 6% regular 6 nylon fiber 3d x 51mm 40%, which was uniformly spread and laminated, was introduced into a pair of calender rolls set to have an upper roll temperature of 160 ° C and a lower roll temperature of 110 ° C. After forming a non-woven fabric having a coarse and dense two-layer structure, the roll surface of the two-layer design non-woven fabric has no low-density layer side on one roll set at 160 ° C. located above the pair of heating rolls. Introduced heat treatment was carried out so as to make contact under pressure to obtain a nonwoven fabric sheet having a basis weight of 190 g / cm ² and a thickness of 0.65 mm.

The following table shows the physical properties of the non-woven fabric trap portion base materials of the examples and comparative examples obtained as described above and the test results when they were assembled and evaluated as a trap member of a self-processing photographic film unit.

[Effect of the invention] Since the present invention is configured as described above, as shown in the table, the trap portion base material of the self-processing photographic film unit using the developer absorbing base material manufactured by the manufacturing method of the present invention is:
The excess developing solution is instantaneously captured and stored, and because it has sufficient compression hardness against external pressure, even if external pressure is applied to the trap section due to user's carelessness after shooting, backflow of processing solution No trouble such as development of external liquid leakage occurs. Further, when the strip-shaped device is incorporated and applied in the trap unit, there is no trouble such as scattering or mixing on the image surface due to falling of fiber pieces.

Further, the present invention is a one-layer type fiber aggregate containing self-adhesive binder fibers, which are thermocompression-bonded by rolls having different heating set temperatures, and subsequently subjected to heat treatment at a temperature equal to or higher than the melting point of the binder fibers to obtain density on the front and back surfaces. Since the difference is appropriately adjusted and formed, there is an advantage that the manufacturing method can be made continuous and can be manufactured in one step. Since the density gradient is formed like the conventional two-layer type, the fiber composition is changed and designed for each layer. It is an invention that has an excellent effect that the steps can be shortened without the need for stacking.

[Brief description of drawings]

FIGS. 1 and 2 are schematic manufacturing process diagrams showing an example of the embodiment of the present invention, FIG. 3 is a sectional view showing the constitution of a developer absorbing base material for the same photographic film, and FIG. 4 is a nonwoven fabric development using a compression tester. FIG. 5 is a plan view of a self-processing photographic film unit, and FIG. 6 is a partially cutaway sectional view taken along line AA of FIG. Is. 1 ... First sheet member 2 ... Second sheet member 3 ... Container means 4 ... Trap means 5 ... Fiber web 6 ... Needle punch machine 7 ... Needle punch nonwoven fabric 8 ... Upper roll 9 ... Lower Roll 10 …… Nonwoven sheet 11 …… Warm air heat treatment machine 12 …… Heat roll 13 …… One surface side 14 …… Other surface side 15 …… Column holes 16 …… Developer absorption base material for photographic film

Claims (6)

[Claims] 1. A roll in which a fiber assembly containing at least 10% by weight or more of binder fibers having self-adhesiveness is heated and set to a temperature equal to or higher than the melting point of the binder fibers.
After passing through a pair of calender roll gaps configured with a roll set to a temperature not higher than the melting point of the fiber to perform thermocompression bonding, a heat treatment is further performed at a temperature not lower than the melting point of the binder fiber to form a coarse and dense two-layer structure. A method for producing a developer absorbing base material for a photographic film, which comprises forming a non-woven sheet. 2. A roll in which a fiber assembly containing at least 10% by weight or more of binder fiber having self-adhesiveness is heated and set to a temperature not lower than the melting point of the binder fiber.
A pair of calender rolls configured with a roll set to a temperature not higher than the melting point of the fibers are passed through a gap to heat-compress,
A developer for a photographic film, characterized by forming a non-woven fabric sheet by forming a coarse-dense structure in which the density gradually changes from one surface side to the other surface side, and then subjecting it to a heat treatment process at a temperature equal to or higher than the melting point of the binder fiber. A method for manufacturing an absorbent substrate. 3. A polyester fiber assembly in which at least 50% by weight or more of self-adhesive polyester binder fiber is mixed and uniformly spread and laminated, and after entangled by a needle punching process, After passing through a pair of calender roll gaps composed of a roll set to a temperature of heating and a roll set to a temperature not higher than the melting point of the fiber, the fiber assembly is integrally thermocompressed,
Furthermore, by subjecting the binder fiber to heat treatment at a temperature not lower than the melting point of the binder fiber without pressing, the fiber density on one surface side of the integrated fiber assembly is 0.35 g / cm ³ or more, and the other surface side is 0.25 g / cm ³ The following non-woven sheet having a coarse and dense two-layer structure is used, and the compression work Wc (g · cm / cm ² ) of the above-mentioned non-woven sheet is
A method for producing a developer-absorbing base material for a photographic film, which comprises forming the compression elastic modulus Rc (%) to be 0.20 or less and 40 or more. 4. The fiber density on one surface side of the developer absorbing base material produced by the production method according to claim 1 or 3 is 0.35 g / cm ³ or more, and the other surface side is 0.25 g / cm ^3. It has the following coarse and dense two-layer structure and a compression work Wc (g · cm / cm ² ) of 0.
A developer absorbing base material for a photographic film, which has a compression elastic modulus Rc (%) of 20 or less and 40 or more. 5. The developer absorbing base material produced by the production method according to claim 1 or 2 is composed of polyester fibers having a fineness of 1 to 20d, and the polyester fibers are self-adhesive in an amount of at least 10% by weight or more. A developer absorbing base material for a photographic film, which is a non-woven fabric sheet containing a functional binder fiber. 6. A self-processing photographic film unit comprising the base material according to claim 4 or claim 5.