JPH0645964Y2 - Packaging material for photographic materials - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a packaging material suitable for a photosensitive material, particularly for a photographic photosensitive material.

[Conventional technology]

Various types of packaging materials for photographic light-sensitive materials have been widely put into practical use, and various performances are required according to their use.

A packaging material that completely blocks light is used as a packaging material for a photographic light sensitive material that loses its quality value when exposed to light. In this case, the required properties are gas barrier properties,
Light-shielding property, moisture-proof property, antistatic property, physical strength (breaking strength, tear strength, impact puncture strength, gelbotest strength, abrasion strength, etc.), heat seal appropriate (heat seal strength, hot tack property, foreign matter seal property, etc.) , Sliding properties, suitability for automatic bag loading, interlayer peeling strength, sliding properties, etc. It is difficult to combine these properties with a single-layer film material, and conventionally, generally, high-pressure branched low-density polyethylene (hereinafter referred to as LDPE Show) Paper, aluminum foil, with very thick single layer film of resin or LDPE film layer
Composite laminate films with flexible sheets such as cellophane have been used. An example of the composite laminate film is shown in FIG. 12, which is one in which the metal foil layer 8 is laminated on the LDPE light-shielding film layer 7 via the adhesive layer 5, and further the flexible sheet layer 4 is laminated via the adhesive layer 5. It is a thing.

As for color photographic paper, as shown in Fig. 13,
In addition to the example shown in FIG. 12, there was also a structure in which an LDPE light-shielding film layer 7 was laminated via an adhesive layer 5 to form a 7-layer structure.

The present inventor has conducted earnest research to improve a packaging material for a photosensitive material, and has already disclosed what has improved physical strength by combining two layers of uniaxially stretched film (JP-A-57-6754). ing. For example, as shown in FIG. 15, a uniaxial molecular orientation light-shielding film layer 9 is laminated on both sides of a metal foil layer 8 with an adhesive layer 5 interposed therebetween.

Further, in a laminated film including three layers formed by laminating uniaxial molecular orientation thermoplastic resin film layers on both sides of a sheet-shaped foam, the thickness of the sheet-shaped foam is 0.3 to 2.0 mm and the expansion ratio is 5 to 5. A 50-fold bilayer uniaxial molecular orientation film layer is a laminated film in which the molecular orientation axes are heat-melt-bonded on both sides of the foam with or without the heat-melt adhesive layer so that they intersect at an angle of 30 degrees or more. The thickness is 40-85% of the theoretical sum of each layer
It has already been disclosed a laminated film excellent in impact hole rake strength and gelbotest strength compressed to a thickness (residual thickness ratio) and having a small curl, which is particularly excellent as a packaging material for heavy objects. (Japanese Patent Laid-Open No. 59-201848) Furthermore, regarding the packaging material using L-LDPE resin,
Consists of polyethylene-based polymer and 1% by weight or more of light-shielding substance, and 50% by weight or more of all ethylene-based polymer is L-LD
One having at least one light-shielding film layer which is a PE resin has already been disclosed (JP-A-58-132555). For example, as shown in FIG. 16, an L-LDPE light shielding film layer 1, a metal foil layer 8 and a flexible sheet layer 4 are laminated with an adhesive layer 5.

[Problems to be solved by the invention] Although the conventional composite laminate film is configured to improve the physical properties described above, a metal thin film layer is used to improve gas barrier properties, antistatic properties, moisture resistance, etc. When laminated, heavy products, roll film products with sharp edges, and the like still have insufficient physical properties, and there are drawbacks such as tearing and puncturing during the packaging operation, and peeling off of the heat-sealed portion. Furthermore, if a large amount of a light-shielding substance such as carbon black is added, the physical strength deteriorates significantly. Therefore, the addition amount should be around 3% and the thickness of the film laminated with other flexible sheet layers should be 100 μm or more. It was For this reason, the wrapping has a high rigidity of the laminated film, deteriorates the workability of the wrapping, and is expensive in terms of cost.

Further, when the thickness of the film is 100 μm or more, not only the film moldability is deteriorated, but also the film cooling property is deteriorated to cause a difference in the slip characteristics between the front and back, and the appearance and physical characteristics are deteriorated. For example, even with the laminated film having a seven-layer structure shown in FIG. 13, tear strength, impact puncture strength, gelbotest strength, etc. were insufficient.

The packaging material described in JP-A-59-201848 has improved physical strength such as tear strength, impact drilling strength, and gelbotest strength, but this laminated film has a large thickness.
The heat-sealing suitability for securing the light-shielding property and the moisture-proof property was poor, and it was expensive and bulky. In addition, since it is not suitable for automatic bag making, a heat-resistant film is sandwiched between heat-sealing surfaces, and the product is inserted into a bag made by a heat sealer using a special cooling device and hermetically sealed, which is very expensive packaging.

Furthermore, the conventional packaging material containing a metal foil layer is not always good in tear strength, impact puncture strength, heat seal strength, gelbotest strength and the like.

An object of the present invention is to solve the above problems and to provide an inexpensive packaging material having high physical strength and good light-shielding properties.

[Means for solving problems]

The present invention has been made in order to achieve the above object, and simultaneously co-extrudes an L-LDPE light-shielding film layer containing a specific substance at a specific concentration by an inflation method to form two co-extruded L-LDPE light-shielding film layers. However, the film formability, physical properties, light-shielding property, etc. are improved from a single-layer film having substantially the same resin composition and substantially the same thickness.

That is, at least ethylene and α with 3 to 13 carbon atoms
-Simultaneous two-layer coextrusion independently formed of linear low-density polyethylene (hereinafter referred to as L-LDPE) resin made of olefin, two L-LDPE light-shielding film layers containing specific carbon black and a lubricant. Inflation L-
LDPE light-shielding film layer (Hereinafter, simultaneous two-layer co-extrusion L-LD
Abbreviated as PE light-shielding film layer. ) Is provided, it is a packaging material for a photographic light-sensitive material.

The packaging material for a photographic light-sensitive material of the present invention is characterized in that it has two simultaneous co-extruded L-LDPE light-shielding film layers. If this co-extruded L-LDPE light-shielding film layer is provided, it may be composed of only the co-extruded L-LDPE light-shielding film layer, or may be laminated with a flexible layer and a metal foil layer.

This co-extruded L-LDPE light-shielding film layer consists of two layers of L-LD
It consists of a PE light-shielding film layer. Both L-LDPE
The thickness or composition of the light shielding film may be different.

This co-extruded L-LDPE L-constitutes the light-shielding film layer
The LDPE light-shielding film contains an L-LDPE resin, a specific carbon black, and a lubricant, and the L-LDPE resin may be 35% by weight or more in each component and the largest by weight. For example, in the case of the least amount of L-LDPE resin, L
-LDPE resin 35% by weight, carbon black 7% by weight,
This is the case where the LDPE resin is 34% by weight, the lubricant is 1% by weight, and the ethylene ethyl acrylate (hereinafter referred to as EEA) resin is 23% by weight. Generally, the L-LDPE film layer means that 50% by weight or more of the film layer is the L-LDPE resin, but in the present invention, the weight% of the L-LDPE resin is the same as the above example.
Is included, even if it is 50% by weight or less. However, the L-LDPE resin content is preferably 50% by weight or more, and particularly preferably 60% by weight or more.

In the present invention, 50 in each component of the L-LDPE light shielding film layer
Weight% or more is L-LDPE resin, 1% to 7% by weight
Is a furnace carbon black having a pH of 6 to 8, 0.02
Most preferably, an L-LDPE light-shielding film layer having a thickness of each layer of 10 to 120 μm and containing 0.5 to 50% by weight of a fatty acid amide lubricant is used.

The balance resin other than the L-LDPE resin in the component of the L-LDPE light-shielding film layer is preferably substantially LDPE resin, but partially other thermoplastic resin, particularly preferably polyolefin-based resin. Resins such as ethylene-vinyl acetate copolymer resin (hereinafter referred to as EVA resin), EEA resin, ethylene-methyl acrylate copolymer resin (hereinafter EM
A), an ethylene-acrylic acid copolymer resin (hereinafter referred to as EAA), a polyisobutylene resin, etc. may be contained within a range not changing the basic characteristics.

The L-LDPE film layer is called the third polyethylene film, and is a low-cost, high-strength film that meets the demands of the times of energy saving and resource saving, which have the advantages of both medium- and low-pressure polyethylene films. The composition is a copolymer obtained by copolymerizing ethylene and an α-olefin having 3 to 13 carbon atoms, preferably 4 to 10 carbon atoms, and a linear straight chain having an ethylene content of 86 to 99.5 mol% and short branching. It is a low-medium density polyethylene resin having a structure.

In general, L-LDPE resin (L inear L ow D ensity Poly
It is a low-density polyethylene resin called etylene, which is an abbreviation for linear low-density polyethylene. The polymerization process includes a gas phase method using a low pressure apparatus, a liquid phase method and an ionic polymerization method using an improved high pressure apparatus. Particularly, the low-pressure L-LDPE resin is preferable because it is low in cost.

Specific examples of product names are Unipol (UCC), Dow Rex (Dow Chemical Co.), Sclere (DuPont Canada), Marlex (Phillips), Neo-Zex and Ulto-Zex (Mitsui Petrochemical), Nisseki Linirex. (Nippon Petrochemical), Stamirex (DSM), NUC
Examples include polyethylene-LL and TUFLIN (Nippon Unicar). As the α-olefin, butene-1, octene-1, hexene-1, 4-methylpentene-1, heptene-1 and the like are used, and the amount thereof is about 0.5 to 1.5 mol% of the polymer. The density is generally considered to be low to medium density, but most commercial products have a density within the range of 0.87 to 0.95 g / cm ³ .

Among these L-LDPE resins, the ethylene content of 90 to 90 is particularly preferable in terms of physical strength and heat seal strength.
99.5 mol%, α-olefin content 0.5 to 10 mol%, melt index (hereinafter referred to as MI) 0.4 to 30 g / 10 minutes (A
STMD-1238), density 0.870-0.940g / cm ³ (ASTM D-150
5), L-LDPE resin produced by low pressure liquid phase process and gas phase process in which α-olefin has 6 to 8 carbon atoms.

The most preferred representative product name is ethylene having 4-methylpentene-1 having 6 carbon atoms as an α-olefin side chain.
As an L-LDPE resin that uses, there is Ultzex of Mitsui Petrochemical Co., Ltd., which has 8 carbon atoms as an α-olefin side chain.
Examples of L-LDPE resins using ke octene-1 include Stamilex of DSM and Dowlex of Dow Chemical. (The above three products are all L-based by the liquid phase process of the low pressure method.
LDPE resin. ) TUFLIN manufactured by Nippon Unicar Co., Ltd., which uses hexene-1 as an α-olefin side chain, is a low pressure gas phase process product.

L-LDPE film made of L-LDPE resin is
Although it is superior to the LDPE film made of LDPE, it has been conventionally unsuitable as a packaging film due to its poor transparency, difficulty in processing, occurrence of blocking between films, lack of lubricity, etc.

The present inventors have used an L-LDPE film using an L-LDPE resin, which has heretofore had many problems as a packaging film, instead of an LDPE film using an LDPE resin, by using a carbon film. The effect of black formulation was tested. As a result, an unexpected result was found that, when carbon black was mixed with the L-LDPE resin, the physical strength was significantly increased, contrary to the case of the LDPE resin.

That is, the LDPE film is originally lower in strength than the L-LDPE film, but particularly when carbon black is added, the strength is significantly reduced. On the other hand, the strength of the L-LDPE film is greatly improved by adding carbon black.

The effect of carbon black blending is apparent at 1% by weight, and becomes prominent when it exceeds 3% by weight, but if the blending amount is further increased, many spots are generated and the cost is increased. If the amount exceeds 30% by weight, in particular, black spots often occur due to poor dispersion of carbon black, which becomes a problem in terms of poor light-shielding property due to pinholes. Moreover, the cost becomes high. Hygroscopicity, flatness, film surface strength, heat sealability, and contamination of photographic photosensitive materials are also problems as packaging materials for photographic photosensitive materials. Therefore, the amount of carbon black compounded is economical, the occurrence of scratches, tear strength, etc. Considering
0.1 to 15% by weight is preferable, and 1 to 7% by weight is particularly preferable.

Carbon black, which is the second composition essential for the L-LDPE light-shielding film of the present invention, which improves the light-shielding property, antistatic property, antiblocking property, moistureproof property, and physical strength, will be described.

When carbon black is classified by raw material, gas black, oil furnace black, channel black,
Examples include anthracene black, acetylene black, oil smoke, pine smoke, animal black, vegetable black, and the like.
Among these, furnace carbon black is preferable from the viewpoints of light-shielding property, cost and physical properties improvement, and acetylene carbon black and Ketjen carbon black which is a modified by-product carbon black are preferable because they are expensive but have an antistatic effect. If necessary, two or more kinds can be mixed according to the required characteristics. On the other hand, among these carbon blacks, the present invention has a pH of 5 to 9 and an average particle size of 10 to 120.
Use mμ. Especially pH 6-8, average particle size 15-30
Oil furnace carbon black of mμ is preferred.
By using those having such a pH and a particle size, the fog generation on the photographic light-sensitive material is small, the increase or decrease in the photosensitivity is small, the light-shielding ability is large, it does not adversely affect the photographic light-sensitive material, Even when it is added to the plastic resin film, it is possible to obtain a packaging material having various advantages such as difficulty in generating carbon black lumps and fisheye pinholes.

Examples of the form of use in which carbon black is mixed with a resin include a powder addition method, a paste addition method, a moisturizing addition method, a compound method, and a masterbatch method. Of these, the masterbatch method is preferable in terms of cost and prevention of contamination of the workplace.

In Japanese Patent Publication No. 40-19616, there is disclosed a method for preparing a master batch of polymer carbon black by dispersing carbon black in a solution of a polymer dissolved in an organic solvent. Discloses a method of dispersing carbon black in polyethylene to form a masterbatch.

In the case of the masterbatch method, carbon black is first mixed with LDPE or a polyolefin resin at a high concentration of 2% by weight or more and generally 10% by weight or more to prepare a masterbatch. This masterbatch is weighed so that the amount of carbon black in the final product becomes a predetermined value, and mixed with L-LDPE resin.

Two advantages can be recognized with this method. First, mixing and dispersing is easier than when carbon black is directly mixed with the L-LDPE resin, resulting in cost reduction and improved fish eye.

Secondly, the LDPE or the mixed system of the polyolefin resin and the L-LDPE resin is superior to the L-LDPE resin alone in the processability in the case of producing a film. L as a masterbatch resin for cost reduction of carbon black mixing
-LDPE resin may be used. In particular, a thermoplastic resin having a higher melt index than the L-LDPE resin is preferable for the masterbatch base resin. Copolymer resins such as LDPE, EVA and EEA are particularly preferable.

The inventors of the present invention have used L-LDPE resin and LDPE instead of HDPE or LDPE single resin, which has been a problem as a packaging film in the past.
The effect of carbon black formulation was tested using resins or mixed resins with copolymer resins such as EVA, EEA. As a result, an unexpected result was found that when L-LDPE resin was blended with carbon black, the physical strength was significantly increased, contrary to the case of HDPE single resin or LDPE single resin.

That is, the HDPE-only resin film and the LDPE-only resin film have originally low strength as compared with the L-LDPE-polyolefin resin film, but the decrease in strength is particularly remarkable when carbon black is added. On the other hand, L-LDPE
-The strength of the polyolefin resin film is improved by adding carbon black.

The same applies to the L-LDPE single resin film.
The effects of carbon black compounding of the L-LDPE single resin film and the L-LDPE-polyolefin resin film are as follows.
It clearly appears at 1% by weight, and becomes noticeable when it exceeds 3% by weight. However, if the compounding amount further increases, lumps increase and the cost increases. If it exceeds 30% by weight, abrasion and debris adheres to the photographic light-sensitive material more often due to the generation of spots due to poor dispersion of carbon black and vibration during transportation, and there is a problem in that the light-shielding property is poor due to pinholes. Moreover, the cost becomes high.

Therefore, the amount of carbon black compounded is economical
0.1 to 15% by weight is suitable from the viewpoint of tear strength, etc.
It can be said that weight% is particularly preferable.

The lubricant, which is the third composition essential for the L-LDPE light-shielding film of the present invention, not only improves processing machine suitability and makes it easier to insert the product, but also generates static electricity during film molding and packaging of the photographic light-sensitive material. Is added to prevent film formation, to prevent film blocking, and to improve film formability during film formation by the inflation method.

If the amount of lubricant added is large, the above properties can be greatly improved, but the heat sealability deteriorates, the photographic photosensitive material is adversely affected (development inhibition), sticky, and dust easily attaches. Therefore, the amount of lubricant added is 0.01 to 1.0% by weight. Further, the type thereof is also selected from silicone lubricants, fatty acid amide lubricants and alkylamine lubricants. That is, dimethyl polysiloxane and a fatty acid amide type lubricant (oleic acid amide, erucic acid amide, stearin) which is a lubricant that does not adversely affect the photographic light-sensitive material and improves the above various characteristics and improves the sliding property with the photographic light-sensitive material. Acid amides, esyl acid amides, etc.), and fatty acid series are particularly preferable. An electrostripper manufactured by Kao Soap, which has a slip property and an antistatic effect, is particularly preferable.

Representative examples of commercially available lubricants preferable for the present invention are described below, but the present invention is not limited thereto.

Silicone-based lubricants; Various dimethylpolysiloxanes (Shin-Etsu Silicone, Toray Silicone) Oleamide amide-based lubricants: Armoslip CP (Lion Akzo), Newtron (Nippon Seika), Neutron E18 (Nippon Seika), Amide O (Nitto Kagaku) ), Alflo E10 (Nippon Yushi), Diamond O-200 (Nippon Kasei), Diamond G-200
(Nippon Kasei), etc. Erucamide amide lubricant; Alflo P-10 (Nippon Oil & Fats), etc. stearic acid amide lubricant; Alflo S-10 (Nippon Oil & Fats), Neutron 2 (Nippon Seika), Diamid 200 (Nippon Kasei) Bis fatty acid amide lubricants; Bisamide (Nippon Kasei), Diamid-200 bis (Nippon Kasei), Armowax-EBS (Lion Akzo), etc. Alkylamine lubricants, Electrostripper TS-2 (Kao Soap), etc. L- HDPE is preferably used as the other resin that can be blended if necessary in addition to the LDPE resin in the LDPE resin-based film layer, but partially other polyolefin-based polymer, etc.,
For example, medium density polyethylene (hereafter referred to as MDPE) resin, various polypropylene resins, ethylene-vinyl acetate copolymer (hereafter referred to as EVA), ethylene-ethyl acrylate copolymer (hereafter referred to as EEA), ethylene-methacrylate copolymer (Hereinafter referred to as EMA), polyisobutylene resin,
It is also possible to blend ethylene-acrylic acid copolymer (hereinafter referred to as EAA) and the like within a range in which the basic characteristics are not changed. If necessary, two or more kinds may be blended.

In the L-LDPE light-shielding film layer of the present invention, various kinds of additives other than the above-mentioned essential additives can be added as required.

Typical examples of the additives will be described below, but the present invention is not limited thereto and can be selected from all known substances.

(Types of additives) (Representative examples) (1) Plasticizer; phthalic acid ester, glycol ester, fatty acid ester, phosphoric acid ester, etc. (2) Stabilizer: lead-based, cadmium-based, zinc-based, alkaline earth metal-based, Organotin, etc. (3) Antistatic agents; cationic activators, anionic activators, nonionic activators, double-sided activators, etc. (4) Flame retardants; phosphoric acid esters, halogenated phosphoric acid esters, halides, inorganic substances, etc. Phosphorus polyol, etc. (5) Filler; Alumina, Kaolin, Clay, Calcium carbonate, Mica, Talc, Titanium oxide, Silica, etc. (6) Reinforcing agent: Glass roving, metal fiber, glass fiber, glass milled fiber, carbon fibers (7) coloring agents; inorganic pigments _{(Al, Fe 2 O 3,} TiO 2, ZnO, Cd S , etc.), organic pigments, dyes, etc. (8) blowing agent; inorganic blowing agents (ammonium carbonate, bicarbonate Seo Da) Organic foaming agents (nitroso-based, azo-based), etc. (9) Vulcanizing agents; Vulcanization accelerators, accelerating aids, etc. (10) Deterioration inhibitors; UV absorbers, antioxidants, metal deactivators, Peroxide decomposer, etc. (11) Coupling agent: Silane-based, titanate-based, chromium-based, aluminum-based etc. (12) Various thermoplastic resins, rubber, etc. L-LDPE light-shielding film layers on both front and back sides of the present invention The packaging material for a photographic light-sensitive material having the simultaneous two-layer co-extruded L-LDPE film layer can have various configurations depending on the packaging bag used and the like. That is, simultaneous two-layer coextrusion L
-LDPE film layer can be composed only, and even if two or more layers of this co-extruded L-LDPE film layer are laminated, at the same time, two co-extruded L-LDPE film layers are additionally provided with a flexible sheet layer, a metal thin film layer, etc. It can also be configured by stacking. For example, the cheapest and most effective layer structure when used as an inner paper for a double light-shielding bag is to coextrude two L-LDPE light-shielding film layers and L-LDPE light-shielding film layers at the same time. It is composed of.
In this case, when the photographic light-sensitive material, which is difficult to distinguish between the front and the back due to the work in a dark room, is packed in the form of a double bag, the inner composition of the L-LDPE light-shielding film layer is the resin composition and the thickness of the layer. Are preferably substantially the same.

The metal thin film layer laminated on the simultaneous two-layer co-extruded L-LDPE light-shielding film layer as needed improves antistatic properties, moisture resistance, light shielding properties, gas barrier properties, and the like.

The typical thickness of this metal thin film layer is 5 to 60 μm.
Aluminum foil, tin foil, lead foil, galvanized thin layer steel sheet, metal foil with a thin film of ionized metal by electrolysis method and thin layer as a packaging material for photographic photosensitive material with high physical strength, moisture resistance, gas barrier There is an inexpensive metal thin film processed (or also referred to as metal thin film formation) in which a metal thin film is processed (a typical example is vacuum deposition) on a flexible sheet layer having excellent properties and antistatic properties. The metal thin film-processed flexible sheet layer which may also serve as a light shielding layer, which is most suitable for the packaging material of the present invention, will be described in detail.

As a metal thin film processing method, a metal thin film is provided on both surfaces or one surface (for example, one surface on the light shielding layer surface side) of a flexible sheet by a conventionally known thin film forming method such as a vacuum evaporation method, a sputtering method, an ion plating method, an electron beam evaporation method. be able to.

Metal thin films include simple metals such as Al, Sn, Zn, Co, Cr, Ni, Fe, Cu,
Although alloys and other metals capable of forming thin films can all be used, aluminum (Al) is most suitable in terms of cost and workability. The most preferable is a vacuum-deposited aluminum thin film-processed biaxially stretched thermoplastic resin film layer.

The metal thin film preferably has a thickness of 55 to 1200 Å in terms of physical strength as a laminate, light-shielding property, antistatic property and moisture-proof property, cost and quality. That is, if the thickness is less than 55 Å, it is not possible to reduce the charge generated on both sides of the metal thin film with the metal thin film processed flexible sheet layer alone, and increase the thickness of the flexible sheet layer and the light shielding layer on both sides of the metal thin film. Otherwise, it is difficult to secure the moisture proof property and light blocking property required for the packaging material for the photosensitive material.

If the thickness exceeds 1200Å, antistatic property, moistureproof property, and light-shielding property can be secured, but there are problems in cost and deterioration of the flexible sheet layer due to heating in the vacuum deposition method, and deterioration of physical strength of the finished laminated film. However, it is difficult to put into practical use. In the case of an aluminum vacuum-deposited film, the thickness is preferably 70 Å or more, and for normal use, the thickness is preferably 80 to 800 Å, more preferably 100 to 600 Å.

Thickness of 5 as a flexible sheet for forming metal thin film
Any paper-like or film-like sheet of ~ 70 μm can be used.

Particularly preferred for the present invention are various kinds of paper, synthetic paper, cellophane, thermoplastic resin film and the like having a thickness of 8 to 40 μm for thinning the packaging material, reducing the cost and securing the physical strength, and the most preferred. Is a uniaxially or biaxially molecularly oriented polypropylene film, polyester film, polyethylene film or nylon film having a thickness of 8 to 30 μm. As the polypropylene film, an unstretched film is preferable because it has a large physical strength and is inexpensive. An ultrathin reinforced film in which a blow ratio is increased by using a high-density polyethylene resin is particularly preferable because it has a large physical strength and is inexpensive.

The surface of the flexible sheet is activated by various known methods to improve the adhesion (also referred to as adhesion) strength between the flexible sheet layer and the metal thin film layer (typically, a vacuum deposited thin film), or an undercoat layer (anchor coating). Layers may be provided.

A typical method for improving the adhesion strength between the flexible sheet layer and the metal thin film layer will be described, but the present invention is not limited to these and any known method can be used. The adhesion strength between the flexible sheet layer and the metal thin film layer is preferably 5 g to 300 g / 15 mm in order to secure the tear strength, the impact punching strength, the drop strength and the gelbotest strength of the laminated film. 5g / 15m
If it is less than m, interlayer peeling failure (generally called delamination) occurs, and if it is 301 g / 15 mm or more, the physical strength is deteriorated and breakage or pinhole failure easily occurs.

Typical examples of the method for improving the adhesion (-adhesion) strength between the flexible sheet layer and the metal thin film layer are (1) a method of activating the surface of the flexible sheet layer (1) a method of activating the surface by corona discharge treatment (2) UV irradiation treatment 〃 (3) Flame treatment 〃 (4) Dichromic acid treatment 〃 (5) Oxidizing agent treatment such as sulfuric acid mixture 〃
etc.

(2) A method of applying a substance having a good affinity for a metal and an excellent metal acceptability to the surface activated in (1) (anchor agent application method) (1) A method of applying a polyester resin solution (2 ) Polyamide resin 〃 (3) Polyurethane resin 〃 (4) Epoxy resin 〃 (5) Cellulose derivative resin 〃 (6) Polyvinyl acetate resin 〃 (7) Polyvinyl butyral resin 〃 (8) EAA, EEA, EMA resin 〃 etc.

(3) A method in which a metal vapor deposition agent is undercoated with a resin such as epoxy resin (2), and after metal vapor deposition is overcoated with a protective layer such as butyral resin (4) Temperature before and after the melting point of the flexible sheet layer before or after metal vapor deposition A method of heat treatment for a short time.

(5) A substance having a good affinity for a metal is added to a flexible sheet layer forming a metal thin film.

If necessary, a protective layer may be provided on the metal thin film in order to improve not only the protection of the metal thin film but also the peeling strength between the metal thin film and the adhesive layer, and adjusting the interlayer peeling strength.

As the metal thin film protective layer, butyral resin, acrylic resin, cellulose resin such as acetic acid fibrin, urethane resin,
Epoxy resin, polyester resin, ionomer resin,
Appropriate resins such as EEA resin, various polyethylene resins and polypropylene resin can be used. Also, wax, gelatin, polyvinyl alcohol and the like can be used.

The protective layer of the metal thin film is preferably formed with an extremely thin thickness. Even if it is produced by the extrusion laminating method, the removal of static electricity becomes insufficient unless the thickness is 50 μm or less.

When the thickness is 5 μm or less by a known solution coating method or spray coating method, the metal thin film can be protected and the effect of removing static electricity is great. Flexible sheet layer, light shielding layer, adhesive layer,
Antistatic agents, metal powders such as carbon black, aluminum powder and aluminum paste, and conductive materials such as carbon fibers can also be mixed into the metal thin film protective layer, and this will further ensure the removal of static electricity. .

As the flexible sheet layer laminated with the simultaneous two-layer coextrusion L-LDPE light-shielding film as required, various thermoplastic resin films, for example, various polyethylene resins, polyethylene copolymer resins, polypropylene resins,
There are known films made of polyvinyl chloride resin, polyvinylidene chloride resin, polyamide resin, polycarbonate resin, fluororesin, polyester resin and the like, and films of modified resins thereof.

A known flexible sheet layer such as a cellulose acetate film, cellophane, a polyvinyl alcohol film, various papers, various non-woven fabrics, wariffs, and a foamed sheet of polyethylene, polystyrene, polyurethane or the like can also be used.

In the case of forming a composite film, it is preferable that a simultaneous two-layer coextrusion L-LDPE light-shielding film layer in which an L-LDPE resin and a light-shielding substance are kneaded is disposed as the innermost layer in contact with the product. This simultaneous two-layer coextrusion L-LDPE light-shielding film layer is an inflation film obtained by coextruding two layers. The flexible sheet layer may be a single layer or a combination of two or more layers.

As the outermost layer of the packaging material for the photographic light-sensitive material, bleached kraft paper, synthetic paper, non-woven fabric, heat-resistant flexible sheets such as cellophane have printability as a packaging material that is hermetically sealed by heat sealing such as a moisture-proof bag, It is particularly preferable because it has high physical strength and does not melt. Polyester films, nylon films, polypropylene films, polyethylene films, etc., which are uniaxially or biaxially molecularly oriented (including stretched films), are also preferable because they contain less impurities and have higher heat resistance than the L-LDPE light-shielding film layer.

The method of laminating the simultaneous two-layer coextrusion L-LDPE light-shielding film layer, the metal thin film layer and the various flexible sheet layers, which are laminated if necessary, in the present invention may be an ordinary method, for example, a heat bonding method (hot plate bonding). Method, impulse bonding method,
Ultrasonic bonding method), a method using an adhesive (including a wet laminating method, a dry laminating method, a hot melt laminating method, an extrusion laminating method, a co-extrusion laminating method), and the like.

Typical adhesives include various polyethylene resins, polypropylene resins, polyolefin-based thermoplastic resins such as polybutene resins, hot melt adhesives, ethylene-propylene copolymer resins, ethylene-vinyl acetate copolymer resins, ethylene-ethyl acrylate. Olefin copolymer resins such as copolymer resins, ethylene-acrylic acid copolymer resins, thermoplastic resins such as ionomer resins, hot-melt adhesives, and other hot-melt rubber adhesives. There is an adhesive for lamination, which is an emulsion or latex adhesive. Representative examples of emulsion adhesives are polyvinyl acetate, vinyl acetate-ethylene copolymers, vinyl acetate-acrylic acid ester copolymers, vinyl acetate-maleic acid ester copolymers, acrylic copolymers, ethylene-acrylic acid. There are emulsions such as copolymers. A typical example of the latex type adhesive is natural rubber,
Rubber latexes such as styrene butadiene (SBR), acrylonitrile butadiene (NBR) and chloroprene (CR) are available. Further, there is a polyurethane adhesive or the like as an adhesive for dry laminating, and a hot melt laminating adhesive in which other paraffin wax, microcrystalline wax, ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer resin, etc. are blended, Known adhesives such as pressure-sensitive adhesives and heat-sensitive adhesives can be used. More specifically, the polyolefin adhesive for extrusion (for extrusion lamination) is various polyethylene resin, polypropylene resin, polybutylene resin,
And copolymers consisting of ethylene and other substances {EVA, EE
A, linear low-density polyethylene (L-LDPE)} resin, DuP
It also includes ionomer resins (ionic copolymers) such as Surlin manufactured by Ont Co., Ltd., and Himilan manufactured by Mitsui Polychemical Co., Ltd., and those graft-polymerized. In particular, low density polyethylene resin is inexpensive and preferable.

These adhesives preferably have a melting point of 5 ° or more lower than that of the layer to be laminated. If there is such a temperature difference, it is possible to completely perform the hot melt adhesion without adversely affecting the flexible sheet.

The thickness of the adhesive layer by the extrusion laminating method using a thermoplastic resin is usually 7 μm to 50 μm, preferably
Although it is 10 μm to 25 μm, it is determined based on the cost, the laminating speed, the total thickness of the laminate, etc., and is not particularly limited to this value.

Hereinafter, representative embodiments of the present invention will be described with reference to sectional views, but the present invention is not limited thereto.

1 to 10 are sectional views of a packaging material for a photographic light-sensitive material according to the present invention.

FIG. 1 is a simultaneous two-layer co-extruded L-LDPE light-shielding film layer 2a obtained by co-extruding two L-LDPE light-shielding film layers 1a containing metal powder or carbon black and a lubricant, which is the most basic of the present invention.

FIG. 2 shows an L-LDPE light shielding film layer 1a with adhesive layers 5 on both sides of a flexible sheet layer 4 (preferably a metal thin film layer).
Is a laminated film in which coextruded L-LDPE light-shielding film layers 2a obtained by simultaneously coextruding two layers are laminated.

FIG. 3 shows L-LDPE light-shielding film layers 1a and 1b ', which have a slightly different thickness or composition on the front and back sides from the co-extruded L-LDPE light-shielding film layer 2a obtained by co-extruding two layers of the L-LDPE light-shielding film layer 1a.
Coextruded light-shielding film layer 2c that coextruded two layers simultaneously
Is a laminated film in which the adhesive layer 5 is laminated.

FIG. 4 shows simultaneous L-LDPE light-shielding film layer 1a on the front and back sides and simultaneously co-extruded intermediate layer 3 having good adhesiveness. Layer coextrusion L-LDPE light-shielding film layer 2a adhesive layer 5
It is a laminated film laminated with.

FIG. 5 shows the adhesive layer made on the simultaneous two-layer co-extruded L-LDPE light-shielding film layer 2a of FIG. 1 through the hole 6 of the perforated flexible sheet layer 4 by the adhesive layer 5 on the opposite side. Simultaneous two-layer co-extrusion L-LDPE light-shielding film layer 2a
It is a packaging material laminated with.

FIG. 6 is a laminated film in which the simultaneous two-layer coextruded L-LDPE light shielding film layer 2a of FIG. 1 is laminated with the flexible sheet layer 4 by the adhesive layer 5.

FIG. 7 shows a laminated film in which the simultaneous two-layer coextrusion L-LDPE light-shielding film layer 2c of FIG. 3 is laminated on the flexible sheet layer 4 by the adhesive layer 5.

FIG. 8 shows that the simultaneous two-layer coextrusion L-LDPE light-shielding film layer 2a shown in FIG. 1 is laminated on the flexible sheet layer 4 (preferably a metal thin film layer) by the adhesive layer 5, and the flexible sheet layer 4 (by the adhesive layer 5). Paper is preferable).

9 to 14 are cross-sectional views of conventional packaging materials.

FIG. 9 shows a single layer of the most basic LDPE resin light-shielding film layer 7 of the prior art.

FIG. 10 shows the LDPE resin light-shielding film layer 7 and the adhesive layer 5 and the metal foil layer 8 that have been conventionally used for products that require moisture resistance.
Is laminated, and the flexible sheet layer 4 is further laminated on the metal foil layer 8 with the adhesive layer 5 to form a laminated film having a five-layer structure.

FIG. 11 shows a packaging material which is conventionally used for the inner paper of a double gusset bag of color photographic paper and is required to have physical strength. In addition to the packaging material of FIG. It is a laminated film having a laminated structure of 7 layers.

FIG. 12 shows a packaging material in which the L-LDPE light shielding film layer 1 is laminated on both sides of the metal foil layer 8 with the adhesive layers 5.

FIG. 13 shows a cross-laminated film in which the uniaxial molecular orientation light-shielding film 9 is laminated on the inner surface of the metal foil layer 8 with the adhesive layer 5 so that the molecular orientation axes intersect.

FIG. 14 shows an L-LD instead of the LDPE light-shielding film layer 7 shown in FIG.
It is a packaging material in which PE light-shielding film layer 1 is laminated.

FIGS. 15 and 16 are specific examples in which the packaging material of the present invention is applied to a double gusset bag used for color photographic paper,
FIG. 15 is a partial cross-sectional view thereof, and FIG. 16 is a cross-sectional view taken in the direction perpendicular to FIG. The double gusset bag 10 is composed of an outer paper 11 and an inner paper 12, and a photographic light-sensitive material 13 is housed inside the double gusset bag 10.

For the outer paper 11, a packaging material or the like shown in the partial sectional views of FIGS. 17 to 20 is used.

FIG. 17 shows the LDPE film layer as a heat seal layer directly on the flexible sheet layer 4 which has been used most often.
14 or a laminated body coated with the L-LDPE film layer 15.

FIG. 18 shows the LDPE film layer 14 or the L-LDPE film layer 15 separately formed on the flexible sheet layer 4 via the adhesive layer 5.
Is a laminated film in which

FIG. 19 shows a laminated film in which the flexible sheet layer 4 and the L-LDPE light shielding film layer 1a separately formed via the adhesive layer 5 are laminated.

FIG. 20 shows a laminated film obtained by laminating two layers of the L-LDPE film layer 15 and the L-LDPE light shielding film layer 1a simultaneously coextruded on the flexible sheet layer 4 via the adhesive layer 5.

The inner paper 12 is formed of the packaging material of the present invention, and for example, the packaging material shown in FIGS. 1 to 8 is used. The outer paper 11 and the inner paper 12 are heat-sealed by the heat-sealing portion 19 at the end portion of the center-sealing portion 18, and are further folded together at the end portion, adhered by the adhesive 16, and the tape 17 is attached. Are sealed.

The packaging material for a photographic light-sensitive material of the present invention is also suitable for packaging a light-sensitive material. The photographic light-sensitive material is a silver halide photographic light-sensitive material, a diazo photographic light-sensitive material, a photosensitive resin, a self-developing photographic light-sensitive material, a diffusion transfer photographic light-sensitive material, etc.The light-sensitive material is discolored by light or hardened and deteriorated. Including all substances

Specific examples thereof include food products such as chocolate, margarine, miso, wine, beer, etc., pharmaceuticals, dyes, and other chemical substances such as developers and mordants for dyeing. It is especially suitable as a packaging material for photographic light-sensitive materials, the quality of which is destroyed by slight amounts of gas, light and humidity.

The packaging material for photographic light-sensitive material of the present invention, when applied to the above-mentioned photographic light-sensitive material or light-sensitive material, is a single flat bag, double flat bag, square bottom bag, self-supporting bag, single gusset bag, double gusset bag, Any known form such as a film sheet, inside a moisture-proof box, or leader paper can be used. Depending on the properties of the laminated film to be used, the method of making a double bag includes a hot plate bonding method, an impulse bonding method, a fusion bonding method, an ultrasonic bonding method, a high frequency bonding method, etc.
By a conventionally known method for adhering a plastic film. In addition, it is also possible to make a bag using an adhesive method using an appropriate glue, an adhesive method using a pressure-sensitive or heat-sensitive adhesive, or the like.

[Action]

The simultaneous co-extruded L-LDPE light-shielding film layer of the packaging material of the present invention is composed of two layers of L-LDPE light-shielding film layer, so that it has the same composition and the same thickness, as compared with the one-layer packaging material. Good film formability and high tear strength, impact puncture strength, etc.

〔Example〕

Hereinafter, a preferred embodiment of the present invention and its effects will be described.

Invented product I L-LDPE light-shielding film layer 1a corresponding to the embodiment shown in FIG.
As an example, L-LDPE resin (trade name: ULTOZEX # 2021L) manufactured by Mitsui Petrochemical Co., which is a copolymer of ethylene and 4-methylpentene-1, and 3 oil furnace carbon black is used.
%, And oleic acid amide 0.1% by weight as a lubricant are added. Two layers of L-LDPE light-shielding film layer 1a with the same composition and the same thickness and a thickness of 25 μm are co-extruded at the same time. -LDPE
It is the light-shielding film layer 2a.

Comparative product I This is an L-LDPE light-shielding film layer 1a formed by molding a single-layer inflation film having the same resin composition as the product I of the present invention corresponding to the embodiment of FIG. 9 and having a thickness of 50 μm.

Conventional product I Comparative product I corresponding to the embodiment shown in FIG. 9 is the LDPE light-shielding film layer 7 formed by a single-layer inflation film having a thickness of 50 μm instead of the L-LDPE light-shielding film layer 1a having a thickness of 50 μm.
Is.

Invention product 2 Thickness of resin composition of Table 1 corresponding to the embodiment of FIG. 1 45
This is a coextrusion L-LDPE light shielding film layer 2a having a total thickness of 90 μm obtained by simultaneously coextruding two L-LDPE light shielding film layers 1a having a thickness of 2 μm into an inflation film.

Comparative product 2 A single-layer blown film having a thickness of 90 μm and the same resin composition as the product 2 of the present invention corresponding to the embodiment of FIG. 9 was formed.
The L-LDPE light-shielding film layer 1a.

Inventive product 3 Total thickness of the inventive product 1 according to the embodiment of FIG.
Simultaneous two-layer coextrusion of L-LDPE light-shielding film layer 2a with a thickness of 15 μm as LDPE adhesive layer 5 as flexible sheet layer 4 Hole 6 of hole Aki film (trade name Panhole) manufactured by Dainippon Plastics Co., Ltd. It is a reinforced laminated film laminated with the simultaneous two-layer coextruded L-LDPE light-shielding film layer 2a on the opposite side by the adhesive layer 5 through which the film is passed.

The present invention product 4 invented product as the outer sheet and the inner sheet 2 Kurupakku paper 4 of 73 g / m ² as a flexible sheet layer 4 embodiment of FIG. 6
With LDPE adhesive layer 5, co-extruded two layers of the product 1 of the present invention L-LD
A combination of laminated films in which PE light-shielding film layers 2a were laminated was used to package color paper in a double gusset bag as shown in FIG. As a result, the physical strength was large and the cost was excellent.

The above examples show typical examples of preferred embodiments as the packaging material for photographic light-sensitive materials of the present invention, but the present invention is not limited to the above, and other known materials and flexible sheet layers Can be combined with.

The results of comparing the layer structure, the materials used, the thickness of each layer, and the characteristics of the products 1 to 3 of the present invention, the products 1 to 2 of comparison, and the conventional product 1 are as follows.
The results are shown in Tables and Table 2.

The L-LDPE resin used in the examples is Ultozex 2021L (MI 2.1 g / 10 min, density 0.920 g / cm ³ ), LDPE manufactured by Mitsui Petrochemical Co., Ltd.
The extrusion adhesion layer 5 is MIRAISON 14 (MI5.1g / 10min, density 0.919g / cm ³ ) manufactured by Mitsui Polychemicals, and the carbon black is Oil Furnace Black 44B (average particle size 21mμ, pH 7. 7) is used as the LDPE film layer by Nippon Unicar DFD-0111 (MI2.4g / 10
Min and a density of 0.923 g / cm ³ ) were used.

The evaluation of Table 2 is based on the following.

Excellent: Very good, Good; Excellent, Fair; Needs improvement within practical limits; Problematic, Poor; Impractical

Density: According to (ASTMD-1505).

Melt index (MI) ... (ASTM D-1238)

A: Sliding angle; Cut out a part of the sheet to be tested and attach it to the bottom of a block measuring 75 mm length × 35 mm width and 200 g load. On the other hand, a part of the sheet to be tested is similarly cut and attached to the inclined surface, the sheet surface of the block is placed on the inclined surface, the inclination angle of the inclined surface is changed, and the block is slid. Read the angle at which it started.

B: Light-shielding property: ASA100 photographic film is put in a bag using each packaging material, completely sealed, and then exposed to 80,000 lux light for 1 hour, and the light-shielding property is detected and evaluated by the degree of fog on the photographic film.

C: Hot-sealing property (hot tack property); Hot-sealing when the open end of two packaging materials (width 15mm) immediately after heat-sealing at 160 ° C is pulled at a peeling angle of 22.5 ° with a load of 45g on one side. Judgment based on the peeling distance (cm).

D; Gelbotest strength; The number of flexing cycles before using a device conforming to the US military standard MIL-B131 and making it impossible to secure the light-shielding property due to pinholes in the packaging material. The higher the number, the higher the strength cannot be evaluated; pinholes occur less than twice.

Need to improve; 3 to 7 times 〃 acceptable; 7 to 50 times 〃 good; 51 to 100 times 〃 excellent; 101 times or more 〃 [Effect of the device] The packaging material of the present invention is a simultaneous two-layer co-extruded L-LDPE film layer However, even a laminated film in which flexible layers are laminated has good tear strength, impact hole strength, gelbotest strength, tensile strength, light-shielding property, moisture resistance, lubricity, heat seal suitability and the like.

And if the same physical strength is guaranteed, the thickness can be significantly reduced compared to the conventional single layer film product, and as a result, the cost can be reduced.

[Brief description of drawings]

1 to 8 are partial cross-sectional views of a packaging material according to an embodiment of the present invention, FIGS. 9 to 14 are partial cross-sectional views of a conventional packaging material, and FIG. 15 is a book. FIG. 16 is a partial cross-sectional view of an embodiment of a packaging bag using the packaging material of the present invention, FIG. 16 is a view obtained by cutting the packaging bag of FIG. 15 in a perpendicular direction, and FIGS. 17 to 20 are outer papers. FIG. 1a, 1b …… L-LDPE light shielding film layer, 2a, 2b, 2c …… Simultaneous 2
Layer co-extrusion L-LDPE light-shielding film layer, 3 ... intermediate layer, 4
...... Flexible sheet layer, 5 …… Adhesive layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-60-29743 (JP, A) JP-A-60-111242 (JP, A) JP-A-58-173653 (JP, A) JP-A-57- 6765 (JP, A) "Lamination Guide", Processing Technology Study Group (Published September 15, 1978) 33 ~ 42

Claims (4)

[Scope of utility model registration request] 1. A linear low density polyethylene resin comprising at least ethylene and an α-olefin having 3 to 13 carbon atoms.
35% by weight or more, pH 5-9, average particle size 10-120 mμ, carbon black 0.1-15% by weight, silicone lubricant,
Simultaneous two-layer coextrusion inflation formed of two L-LDPE light-shielding film layers containing 0.01 to 1.0% by weight of at least one lubricant selected from fatty acid amide lubricants and alkylamine lubricants L-LDPE
Packaging material for photographic light-sensitive material, characterized by comprising a layer of a light-shielding film 2. Simultaneous two-layer coextrusion inflation L-
The packaging material for a photographic light-sensitive material according to claim 1, wherein the layers of the LDPE light-shielding film are two layers of L-LDPE light-shielding film having substantially the same resin composition and substantially the same thickness. 3. Simultaneous two-layer coextrusion inflation L-
The packaging material for a photographic light-sensitive material according to claim 1, wherein a layer of an LDPE light-shielding film is laminated on both sides of a flexible sheet with adhesive layers. 4. The photographic light-sensitive material according to claim 1, 2, or 3, wherein the amount of the linear low-density polyethylene resin in the inflation L-LDPE light-shielding film layer is 50% by weight or more. Packaging material