JP3451502B2 - Packaging materials for photosensitive materials - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging material for a photographic light-sensitive material, and more particularly to a packaging material for a photographic light-sensitive material which has a metal layer to improve environmental suitability and is excellent in moisture resistance.

[0002]

2. Description of the Related Art Conventionally, in order to maintain product quality, photographic light-sensitive materials (hereinafter, also simply referred to as light-sensitive materials) have been variously packaged for each product type. For example, the most commonly used 135 size film is contained in a moisture-proof resin container in a light-shielding container. In the case of roll film of 120 or 220 size, the film is wound around a light-shielding paper in a single core, wound on a shaft, put in a moisture-proof bag, and sealed by heat sealing. Further, in the case of the X-ray film and the sheet film for printing, they are put in a light-proof and moisture-proof bag and then hermetically sealed.

Generally, a photographic light-sensitive material is formed by coating a paper base material coated with a plastic film or resin with a material in which silver halide is dispersed in a hygroscopic material such as gelatin. When stored in, the moisture-proof material absorbs water, the photographic performance fluctuates accordingly, and it becomes more difficult to maintain normal performance.

If not packaged with a moisture-proof packaging material, the following problems are expected to occur in use.

For example, if 10 boxes of sheet-shaped photosensitive material containing 50 sheets are purchased and all are used for 2 months while being stored at 30 ° C. and 85% RH, the photographing conditions of the photosensitive material in the first box,
The shooting conditions of the last box will have to be changed.

This is because the sensitivity of the photosensitive material changes depending on the humidity, and the sensitivity may become higher or lower depending on the type of the photosensitive material. In such a case, the sensitivity is predicted or calculated from many years of experience, and the photographing conditions are changed before use.

However, when it is stored in a high humidity condition, it causes "fog" due to other performance deterioration (a portion of the photographic light-sensitive material which is not exposed is blackened by a developing process as if exposed, a color light-sensitive material). In some cases, there is a light-sensitive material in which the color develops. In this case, the screen becomes unclear and the commercial value may be lost depending on the state.

In order to prevent such a state, it is the current situation that a material having a moisture-proof function is used, and the material is hermetically sealed to improve the storability.

The types of these moisture-proof materials for photographic light-sensitive materials include Japanese Patent Publication No. 2700/1990, JP-A-60-111242 / 60-15.
No. 1045, No. 61-54934, No. 61-189936, No. 62-18546
No. 62, No. 62-18548, No. 62-124946, No. 62-127544
No. 62-184549, JP-A-63-85539, and 64-51940.
No. 1, JP-A 1-195042, 1-209134, 2-64537,
JP-A-3-119349, 3-125139, 2-196238, 2-
No. 146539 is known, and a moisture-proof material for a photographic light-sensitive material, which is excellent in physical strength, low-temperature sealing property, pinhole resistance, light-shielding property, and bag manufacturing required for a moisture-proof bag, is mentioned.

Conventionally, moisture resistance has been achieved by providing an aluminum foil layer and an aluminum vapor-deposited layer. However, the drawback of the packaging material having these metal layers is that the metal layers are not removed during incineration after use. It remains as a residue and accumulates in an incinerator to lower combustion efficiency, and it takes time to treat the residue. This point is also a problem especially in the case of aluminum foil.

Under such circumstances, as a packaging material that solves the above problems while utilizing the characteristics of the conventional metal layer, JP-A-63-169641, JP-A-62-48532 and JP-A-62-48532 There is one described in 64-82935. This is a packaging material using a multi-layer coextrusion film having a light reflecting layer and a light absorbing layer.

However, such a film also has the following drawbacks.

In the case of laminating a transparent flexible layer on which design printing is applied on the light reflecting layer, the light reflecting layer is thickened to prevent the print color from becoming turbid due to the lower light absorbing layer, or It is necessary to increase the amount of reflective material added.

Although the above-mentioned achievement is theoretically possible, there are the following problems when they are produced by the multi-layer coextrusion method. (B) Thickness balance of each layer (distribution)
If the difference is too different, the thickness of the finished film also varies depending on the location of the film, so-called uneven thickness development occurs,
(B) If a certain amount or more of additives are added, the fluidity of the resin when heated will deteriorate, the fluidity balance between layers will be lost, and the thickness will vary, resulting in so-called uneven thickness development. To do.

When variations in thickness occur in this way,
Variations in moisture permeability also occur, and the storability of the photographic light-sensitive material contained therein becomes unstable, so it has been desired to solve these problems.

As a film having less uneven thickness, an extruded film using a T-type die is known, but in this case, it is necessary to use an adhesive for each layer to laminate the films, which causes uneven thickness. There are few multilayer films,
The biggest drawback is that the manufacturing process becomes long and the manufacturing cost increases accordingly. It is further desired to develop a film which has the performance using an extruded film using these T-type dies and is low in cost.

[0017]

SUMMARY OF THE INVENTION An object of the present invention is to provide a packaging material for a photographic light-sensitive material which solves the above problems and is inexpensive and has stable moisture-proof and light-shielding properties.

[0018]

The above objects of the present invention are as follows.
Layer or more light-reflecting layer, and a light-absorbing layer, the amount of the light-reflecting substance added to the light-reflecting layer is 3.0 to 12.0% by weight, and the light-reflecting layer has a total thickness of 82 to 90%, the amount of the light absorbing substance added to the light absorbing layer is 1.0 to 8.0% by weight, and the light absorbing layer has 10 to 18% of the total layer thickness. This is achieved by a material and a packaging material for a photographic light-sensitive material in which the coextruded film thereof is made by an inflation method.

The present invention will be described in more detail below.

A thermoplastic resin film is used for the light reflecting layer and the light absorbing layer of the present invention. An example of the resin used in the present invention is shown below.

The resin can be selected according to need as long as it is a thermoplastic resin generally used in the coextrusion method such as a polyolefin resin, a polyester resin, a polyamide resin, and a polypropylene resin. Polyolefin resin with low water permeability (high density polyethylene (HDPE), low density polyethylene (LDPE),
Linear low density polyethylene (LLDEP) is preferred,
In particular, it is desired that the gold layer is made of polyolefin resin from the viewpoint of recyclability.

The light-reflecting substance added to the light-reflecting layer may be selected from various pigments as required, and may be selected from those described in "Pigment Manual". Examples thereof include white, white lead, titanium white (titanium oxide), antimony white, barium sulfate, magnesium silicate, calcium sulfate, calcium carbonate, clay, chrome yellow, titanium yellow, and synthetic pearl foil.

Among the above-mentioned pigments, white pigments or silver-colored metal powders are preferably used in consideration of laminating a design-printed or a design-printed film on the uppermost layer.

A method for mixing these light-reflecting substances into a resin is described in JP-A-63-169641 and JP-B-40-26196.
No. 43-10362 and Japan Rubber Association Magazine Vol. 56, No. 8 (198
3) It is possible by the method described in P473-488.

The addition amount is preferably 3.0 to 12.0% by weight, particularly preferably 5.0 to 9.0% by weight, and the thickness of the light-reflecting layer is 82 to 90% with respect to the total layers. .
When the content of the light-reflecting substance is 3.0% by weight or less, the color of the lowermost light-absorbing layer does not give a clean color, and the light transmittance increases, which is not preferable in terms of light-shielding property, or 12.0% by weight or more. In this case, so-called lumps and the like are generated due to poor dispersion (the surface becomes lumpy due to lumps of additives), and uneven thickness occurs due to deterioration of the fluidity of the thermoplastic resin. As the light absorbing substance added to the light absorbing layer, carbon black is most preferable, and any carbon black that is commercially available may be used, but when considering the influence on photographic performance, the following commercially available products are used. Is mentioned.

(Brand) Mitsubishi Kasei Co., Ltd .: # 45, # 950 Kiobot: Vulcan-P Denka: Denka Black The method of mixing these carbon blacks into the resin is the same as the method of mixing the light-reflecting substances described above. It is possible to mix according to the method.

The amount of the light absorbing substance added is 1.0 to
It is preferably 8.0% by weight, particularly preferably 3.0 to 6.0% by weight, and the thickness of the light absorbing resin film layer is preferably 10 to 18% with respect to the total layer.

When the amount of the light absorbing material is 1.0% by weight or less, it may be impossible to obtain the required light-shielding property (especially, the high-sensitivity film ISO3200). Occurs and uneven thickness occurs due to deterioration of the fluidity of the thermoplastic resin.

A method for producing a film by three-layer coextrusion (inflation method) using a thermoplastic resin to which the above substances are added is a plastic extrusion molding and its application Sebundo Shinkosha P137. ~ 147 Plastic Handbook, can be manufactured by the method described in Asakura Shoten p727.

When the multilayer film produced by this inflation method is used as a packaging material for a photographic light-sensitive material, the most important thing to note is that there is a variation in thickness (hereinafter referred to as uneven thickness), which results in a finished product. When a film is used and the photographic light-sensitive material is hermetically packaged, the thickness varies depending on the location where the film is used, resulting in variations in moisture permeability, which greatly affects the storage stability of the light-sensitive material. The method according to the present invention eliminates this drawback.

That is, one of the features (1) of the present invention is that the light-reflecting layer is divided into two layers and the layer thickness ratio to the light-absorbing layer is limited.

As a result, the resin flow balance at the time of extrusion is improved and uneven thickness can be reduced.

In particular, by dividing the light-reflecting layer into two parts, it becomes possible to average the uneven thickness of the layer (the effect that the uneven thickness portion of the first layer and the uneven thickness portion of the second layer are displaced). There is a thing.

Further, by averaging the uneven thickness, variations in moisture permeability are eliminated, and at the same time, the light reflectance is also averaged, so that when a flexible layer printed or designed is laminated on the upper layer, color turbidity is not generated. There is also the effect that the product value will disappear and the product value will increase. The second characteristic (2) is that the thickness balance of each layer is limited.

That is, the uppermost layer and the light reflecting layer are based on the total layer thickness.
20-40%, intermediate layer light reflective layer is 50-70% of total layer thickness
%, The lowermost light absorbing layer is 10 to 18% of the total layer thickness, and the thickness of the uppermost layer and the intermediate layer is 82 to 90% of the total layer thickness, and the thickness of the lowermost layer is the total layer thickness. It is a very effective means to improve the flow balance of the thermoplastic resin in each layer and reduce uneven thickness as a result.

According to the above (1) and (2), the deterioration of the moisture permeability due to the uneven thickness, which has been difficult to use in the past, is prevented, so that the treatment is considered to be difficult from the environmental aspect. It is possible to provide a packaging material for photographic light-sensitive materials from which "aluminum" has been removed.

When another flexible layer is laminated on the three-layer coextrusion inflation film produced by the above-mentioned method, the coextrusion inflation may be further carried out, or in addition, Convertec 1990-5 laminating initial course (3) P40 ~ 48 (wet lamination, hot melt lamination, extrusion coating lamination, dry lamination, etc.). In particular, when laminating different kinds of thermoplastic films, curling occurs when laminating by the extrusion coating lamination method, which is not preferable.

In order to obtain a laminate with less curl, a dry lamination method of laminating with an adhesive is preferable.

In this case, the adhesive to be used can be selected as required from those described in Convertec 1993-3 Laminate Beginner Course (23) P40 to P48.

Of these, ester-based and urethane-based adhesives are examples of adhesives that do not affect the photographic performance such as fogging.

[0041]

EXAMPLES Specific examples of the present invention will be described below, but the embodiments of the present invention are not limited thereto.

(Example-1) A laminated film having the following constitution was prepared by a three-layer coextrusion inflation method.

Layer Composition Layer Layer (a): light-reflecting thermoplastic film layer (outermost layer) Layer (b): light-reflecting thermoplastic film layer (intermediate layer) Layer (c): light absorbing thermoplastic film layer (middle and lower layers)

[0044]

[Table 1]

The addition amount of the addition substance indicates the addition amount of the masterbatch.

Thickness of each layer (a) 37μ, (b) 50μ, (c) 13μ Thermoplastic film used Tosoh Co., Ltd. trade name Petrosen-172 low density polyethylene resin light reflecting material Tokyo Ink Co. trade name titanium oxide・ PEX6800 (Titanium oxide concentration 60% by weight) Light-absorbing substance Tokyo Ink Co., Ltd. Product name Carbon black PEX98
6020 (Carbon black concentration 30% by weight) A 12 μm thick polyester resin film was laminated on the (a) layer side of each of the samples with adhesives KW-40 and LX-75A manufactured by Dainippon Ink Co., Ltd. And

Each sample was heat-sealed into a bag, and a color film (Konica Color XG-400) was placed in the dark in a dark room. After sealing, the sample was left at 45 ° C. and 60% RH for 4 months. , Konica designated color film development processing was performed, and the density of the obtained film was measured with a densitometer.

Concentration meter used (concentration meter PDA manufactured by Konica Corporation)
-65 type) The measurement results of blue density are shown below.

[0049]

[Table 2]

The measurement is PET 12μ / Al 9μ / PE 10μ / P
Using a moisture-proof bag having a structure of E80μ as a comparative sample, the film was processed under the same conditions, and the increased density is shown based on the density obtained.

As shown in the table above, when the addition amount is increased,
It can be seen that the storability of the film has deteriorated.

A sample of the same packaging form was exposed for 8 hours at a brightness of 100,000 lux, and then the same treatment was carried out, and the obtained film density was measured using a densitometer. The concentration value indicates the change concentration with respect to the comparative sample.

[0053]

[Table 3]

As shown in the above table, the results show that the light-shielding property becomes insufficient when the addition amount is small.

Next, a multilayer film having the same layer structure as that of sample No. 1 was prepared as a comparative sample as follows by a method other than the present invention.

The film used for each layer was prepared using a T-type die, and a comparative sample was prepared by laminating each layer with an adhesive by the dry lamination method. As a result, in the case of the sample of the present invention, only one dry lamination is required, but the comparative sample requires four times, and the price is about 30% higher than that of the present invention.

(Example-2) In each layer film having the structure shown in Example-1, the thermoplastic film of each layer was changed as follows.

I. Layer a: High density polyethylene (HDP) with a density of 0.992 g / m ² and a melt flow rate of 0.03 g / 10 min.
E) Layer b: 80% by weight of high-density polyethylene used in layer (a), 20% by weight of linear low-density polyethylene (LLDPE) with a density of 0.915 g / m ² , melt flow rate of 1.30 g / 10 min c-layer: density 0.907 g / m ² Melt flow rate 3.30 g / 10
40% by weight of linear low-density polyethylene and a density of 0.920,
Melt flow rate 0.3 g / 10 min Low Low Density Polyethylene (LDPE) 60% by weight II. Layer a: High density polyethylene (HDPE) with a density of 0.964 melt flow rate 1.0 g / 10 minutes b Layer: Linear low density polyethylene (LLDPE) with a density 0.930 melt flow rate 2.0 g / 10 minutes c Layer: Density 0.924 melt flow Low density polyethylene (LDPE) having a rate of 1.0 g / 10 min The amounts of the light-reflecting substance and the light-absorbing substance added to each layer in the films I and II are shown below.

[0059] The same additives as in Example-1 were used.

The thickness of each layer of the film thus prepared was changed as follows to prepare a sample.

[0061]

[Table 4]

Each sample was heat-sealed into a bag, and a color film (Konica XG-400) was placed naked in a dark room, sealed, and allowed to stand at 30 ° C. and 60% RH for 1 year. The designated color film was developed, and the density of the obtained film was measured with a densitometer.

Concentration meter used (Konica Corporation PDA-65
Type) The measurement results of the blue density are shown below. In addition, the numerical value shows the increase value of the density in comparison with the film stored frozen.

[0064]

[Table 5]

From the above results, it can be seen that the present invention is excellent in retention.

In addition, except that the (b) layer of the film I was divided into two parts by the same resin and four layers were coextruded to prepare samples, Nos. 1 to 5 were prepared under the same conditions, and the same evaluation was carried out.
I got exactly the same result.

[0067]

As described above, the present invention has the following effects.

According to the first aspect of the present invention, two or more light reflecting layers are provided (or laminated).
As a result, uneven thickness in the light-reflecting layer (the thickness of the layer is not constant depending on the region) is eliminated, and moisture resistance is stable, so when stored, the film has adverse effects such as fogging due to humidity. Never give.

Further, according to the second aspect of the present invention, the amount of the reflective substance added to the light-reflecting layer is regulated, so that the light-shielding property is enhanced, and no spots are generated and uneven thickness is also eliminated. You can

According to the third aspect of the invention, since the amount of the absorbing substance added to the light absorbing layer is regulated, a stable light-shielding property is obtained, and no spots are generated and uneven thickness is not generated. can do.

According to the invention described in claim 4, the packaging material for photographic light-sensitive material of the present invention can be obtained easily and inexpensively with a good yield.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI B32B 7/02 103 B32B 7/02 103 // B29L 9:00 B29L 9:00 (58) Fields investigated (Int.Cl. ⁷ , DB name) G03C 3/00 565 G03C 3/00 560

Claims (2)

(57) [Claims] 1. A packaging material for a photographic light-sensitive material, which comprises two or more light-reflecting layers and a light-absorbing layer , wherein
The amount of the light-reflecting substance added to the layer is 3.0 to 12.0% by weight,
The light-reflective layer has a total layer thickness of 82-90%, and
The amount of the light absorbing substance added to the light absorbing layer is 1.0 to 8.0 weight.
% And said light absorbing layer has 10-18% of the total layer thickness
A packaging material for a photographic light-sensitive material, which is characterized in that 2. The packaging material is a coextrusion inflator.
The method according to claim 1, characterized in that
Packaging material for photographic light-sensitive materials.