JPH0677133B2 - Packaging material for photographic materials - Google Patents

Description

The present invention relates to a packaging material suitable for a photographic light-sensitive 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, required properties include packaging material slit suitability, gas barrier property, light shielding property, moisture proof property, rigidity, physical strength (breaking strength, tear strength, impact drilling strength, gelbotest strength, abrasion strength, etc.), heat seal suitability ( Heat seal strength, cut seal property, hot tack property, foreign substance seal property, etc.), heat seal strength over time, antistatic property, flatness, and slip property. It is extremely difficult to combine these various properties with a single film material, and conventionally, a very thick, high-pressure branching low-kneading method in which carbon black, a pigment, etc. as shown in FIG. Density polyethylene (hereinafter referred to as LDPE) resin light shielding film layer
A single layer film of 7a or a composite laminate film of a LDPE resin film and a flexible sheet layer such as paper, aluminum foil or cellophane has been used. An example of a composite laminate film is shown in Fig. 6, which is used for roll-shaped color photographic paper products that require moisture resistance and physical strength. LDPE resin light-shielding film layer 7a has an adhesive layer. 4, an aluminum foil layer 8 is laminated via the adhesive layer 4, a flexible sheet layer 5 is laminated via the adhesive layer 4, and an LDPE resin light-shielding film layer is further laminated thereon via the adhesive layer 4.
7a is laminated.

The present inventor has conducted diligent research to improve a packaging material for a photosensitive substance, and has already disclosed what has improved physical strength by combining two layers of uniaxially stretched film (Japanese Patent Laid-Open No. 57-6754). ing.

Further, in a laminated film obtained by laminating a uniaxial molecular orientation thermoplastic resin film on both sides of a sheet-shaped foam, the thickness of the sheet-shaped foam is 0.3 to 2.0 mm, the expansion ratio is 5 to 50 times, and two layers are formed. We have already disclosed a laminated film in which a uniaxial molecular orientation film is adhered to both sides of a foam so that the molecular orientation axes intersect at an angle of 30 degrees or more (JP-A-59-201848).

[Problems to be solved by the invention]

The conventional composite laminate film is configured to improve the above-mentioned physical properties. However, because aluminum foil is used to prevent moisture and prevent static electricity, the physical properties are not sufficient for heavy products and roll film products with sharp edges. There was a defect such as the part peeling off. Furthermore, when a large amount of a light-shielding substance such as carbon black is added, the physical strength deteriorates and the heat-sealability deteriorates. The amount added is around 3% by weight and the total film thickness is 70%.
It was necessary to set the thickness to at least μm. For this reason, the bulkiness of the bulk laminate film is increased, the packaging workability is deteriorated, and the packaging is expensive.

For example, the laminated film of 7-layer structure shown in Fig. 6, which was used for packaging roll-shaped color photographic paper, also uses aluminum foil for moisture resistance and antistatic property, so tear strength, impact hole strength, gelvotest strength. Etc. are lacking. The packaging material described in JP-A-59-201848 has improved physical strength such as tear strength, gelbotest strength and impact hole puncture strength. However, this laminated film has a large thickness and is not suitable for heat-sealing for securing high light-shielding and moisture-proof properties for high-sensitivity photographic light-sensitive materials, and is not suitable for automatic bag making. The product was inserted into a bag made by a heat sealer using a special cooling device with a heat-resistant film sandwiched on the surface and sealed, resulting in very expensive packaging.

The present invention improves the above problems and provides an inexpensive packaging material for a photographic light-sensitive material with improved product insertability, heat seal strength over time, physical strength, heat seal suitability, antistatic property, and the like. To aim.

[Means for solving problems]

In order to achieve the above object, the present invention has a melt index of 0.4 which is a copolymer of ethylene and α-olefin.
To 30 g / 10 min, density linear low density polyethylene resin 0.870~0.940g / cm ³ is 30 to 99.49 wt%, carbon black 0.5% to 10% by weight, and a lubricant is 0.01 to 1.00 wt% of heat-sealing Layer, which has a static friction coefficient of 0.12 to 0.37, and a thermoplastic resin that has a static coefficient of friction
It is characterized by comprising a simultaneous two-layer coextrusion light-shielding film which is composed of an outer layer having a value of 0.05 or more and an absolute value of 0.19 or more, and the adhesive strength between the inner layer and the outer layer is 10 g / 15 mm width or more. It constitutes a packaging material for materials.

The linear low-density polyethylene resin, which is a copolymer of ethylene and α-olefin essential for the inner layer of the present invention, is generally
L-LDPE resin is a (L inear L ow D ensity P oly e tylene i.e. linear low density acronym abbreviations polyethylene) linear low density polyethylene resin called. As the polymerization process, gas-phase method using medium- and low-pressure equipment, liquid-phase method (solution method)
There is a high-pressure remodeling method that uses a high-pressure improvement device. Particularly, the low-pressure L-LDPE resin is preferable because it is low in cost.

If you show a concrete example with a product name, Unipol and TUFLIN (UCC
Company), Dow Rex (Dow Chemical Company), Sclere (DuPont Canada Company), Marrex (Phillips Company), Neo-Zex and Ulto-Zex (Mitsui Petrochemical), Nisseki Linierex (Nippon Petrochemical), Idemitsu Polyethylene-L (Idemitsu) Petrochemical), Stamilex (DSM
Company), NUC polyethylene-LL (Nippon Unicar) and the like. As the α-olefin, butene-1, octene-1, hexene-1, 4-methylpentene-1, heptene-1, etc. are used, and the amount thereof is 0.5 to 15 of the polymer.
It is about mol%. The density is generally considered to be low or medium, but most of the commercially available products have a density in the range of 0.87 to 0.94 g / cm ³ . Among these L-LDPE resins, particularly preferable in terms of cost, physical strength and heat seal strength,
Ethylene content 90 ~ 99.5mol%, α-olefin content 0.5 ~ 10mol%, melt index (hereinafter MI) 0.4 ~ 30g / 10min (ASTMD-1238-E condition), density 0.8
The L-LDPE resin is 70 to 0.940 g / cm ³ (ASTM D-1505) and has a carbon number of α-olefin of 6 to 8 by a low pressure liquid phase process and a gas phase process. The most preferable representative product name is Ultozex of Mitsui Petrochemical Co., Ltd. as an L-LDPE resin using 6-methylpentene-1 having 6 carbon atoms as an α-olefin side chain in ethylene.
L-LDPE resins using octene-1 having 8 carbon atoms as olefin side chains include DSM's Stamilex and Dow Chemical's Dourex, etc. (The above three products are the low pressure liquid phase process) L-LDPE resin by.).

Examples of low-pressure vapor-phase process products include TUFLIN manufactured by UCC, which uses hexene-1 as an α-olefin side chain.

The L-LDPE resin may be used alone or as a mixture with other various thermoplastic resins and various additives. In particular, to secure better characteristics than other resins such as physical strength (tear strength, impact hole strength, etc.) and heat sealability (ensure seal strength, hot tack, foreign matter sealability, etc.). It is essential that the resin composition contains at least 30% by weight of L-LDPE resin. It goes without saying that the L-LDPE resin may be a mixed composition of two or more L-LDPE resins having different α-olefins.

Polyolefin resin, especially LDPE resin, EVA resin (ethylene-vinyl acetate copolymer resin), EEA resin (ethylene Ethyl acrylate copolymer resin) is preferred. The essential carbon black for the inner layer is for maintaining the heat seal strength over time, light shielding property, antistatic property and the like, and the addition amount thereof is 0.5 to 10% by weight. This added amount is the physical strength of the film, film moldability, moisture resistance, antistatic property,
Limited in terms of film quality. If it is less than 0.5% by weight, the light-shielding property, heat seal strength over time, and antistatic property cannot be satisfied, and if it is 10% by weight, the hygroscopicity becomes large and the film formability deteriorates, but the physical strength, heat-sealing property, and moisture-proof property are alleviated. The characteristics of are problematic. Further, it is worn by rubbing with the photographic light-sensitive material and a large amount of black powder is generated, which causes a spot-like failure in the light-sensitive material. In order to reduce the surface resistance value to 10 ¹⁰ Ω or less with carbon black alone, it is necessary to add conductive carbon black.

Representative examples of the conductive carbon black include acetylene carbon black and Ketjen carbon black which is a modified by-product carbon black. It is also preferable to blend various conductive materials with various carbon blacks to improve the antistatic effect.

For example, various metallic conductive particles and various antistatic agents (described in detail in "Antistatic Agents" (Koushobo) by Hideo Marumoshi), metal powders, fibrous conductive fillers or conductive fillers in liquid form. It is also preferable to blend carbon black with a known conductive substance such as a polymer and / or a solvent-soluble polymer. Among the carbon blacks of the present invention, those having a pH of 5 to 9 and an average particle size of 10 to 120 mμ are preferable, and an oil furnace carbon black having a pH of 6 to 8 and an average particle size of 15 to 30 mμ is particularly preferable in terms of ensuring dispersibility and light shielding properties. . In particular, by using such a pH and average particle size packaging material for a photographic light-sensitive material, the occurrence of fog is small, the increase or decrease in the photosensitivity is small, the light-shielding ability is large, and the photographic light-sensitive material is not adversely affected. It is possible to obtain a packaging material having various advantages such that pinholes such as lumps of carbon black and fish eyes are less likely to occur even when it is added to the thermoplastic resin film without giving it.

There are various types of usage of compounding carbon black with L-LDPE resin, such as powder addition method, paste addition method, moisturizing addition method, granular addition method, compound method, master batch method, etc. It is preferable in terms of preventing contamination of the workplace.

In JP-B-40-26196, which is a known document, carbon black is dispersed in a solution of a polymer dissolved in an organic solvent,
As a method for preparing a master batch of polymer carbon black, JP-B-43-10362 discloses a method for preparing a master batch by dispersing carbon black in a polyethylene resin.

In the case of the masterbatch method, first apply 10 to a polyolefin resin (preferably LDPE, L-LDPE, EVA, EEA, EMA, etc.).
A masterbatch is prepared by mixing carbon black in a high concentration of not less than 30% by weight, generally not less than 30% by weight. Then, the master batch pellets were weighed so that the final amount of carbon black in the inner layer would be 0.5 to 10% by weight, and L-LDPE
Add to and mix with resin or L-LDPE resin.

The lubricant essential for the inner layer does not adversely affect the photographic light-sensitive material,
It is for improving product insertion suitability, blocking prevention, film moldability, peeling antistatic property, and the like. The amount of this lubricant added is to prevent static electricity, product insertion suitability, film formability, blocking prevention, and to prevent stickiness or dust adhesion due to breeding out to photographic light-sensitive materials when the amount added is too large. Therefore, it is 0.01 to 1.0% by weight.

Typical commercially available lubricant names and manufacturer names that do not adversely affect the photographic light-sensitive material are listed below, but the present invention is not limited thereto.

(1) Silicon lubricant; various grades of dimethylpolysiloxane (Shin-Etsu Silicone, Toray Silicone, etc.) (2) Oleic acid amide lubricant: Armoslip CP (Lion Akzo), Neutron (Nippon Seika), Neutron E- 18 (Nippon Seika), Amide O (Nitto Kagaku), Alflo E-10 (Nippon Yushi), Diamid O-200 (Nippon Kasei), Diamid G-200 (Nippon Kasei), etc. (3) Erucamide Lubricants: Alflo P-10 (Nippon Yushi), etc. (4) Stearamide amide type lubricants: Alflo S-10 (Nippon Yushi), Neutron 2 (Nippon Seika), Diamid
200 (Nippon Kasei), etc. (5) Bis fatty acid amide lubricants; Bisamide (Nippon Kasei), Diamid 200 bis (Nippon Kasei), Armowax EBS (Lion Akzo), etc. (6) Alkylamine lubricants, electrostripper
TS-2, etc. The inner layer has a coefficient of static friction of 0.12 to 0.37. For this static friction coefficient, a part of the sheet (packaging material) to be tested is cut out and attached to the bottom surface of a block having a length of 75 mm x width 35 mm and a load of 200 g. On the other hand, the sheet (packaging material) to be tested
Similarly, a part of the above is cut and attached to an inclined surface, the sheet (packaging material) surface of the block is placed on the inclined surface, the inclination angle of the inclined surface is changed, and the angle at which the block starts to slide. It is a value obtained as tan θ after reading θ.

If the coefficient of static friction is less than 0.12, the photographic light-sensitive material will move too much in the bag during transportation, causing scratches and frictional fog, and it will not be able to be wound because it is too slippery at the time of winding after film formation or winding in the laminating process. , It is difficult to put it into practical use because it has a bamboo-like shape.

Further, if the coefficient of static friction exceeds 0.37, it is difficult to put the bag in the packaging process of the photographic light-sensitive material, and if it is peeled and put, the bag will be broken or scratches or friction fog will be generated on the photographic light-sensitive material. In the case of a bag, it becomes easy to block, and not only the inner layer and the inner layer may be blocked but also the inner layer and the photographic light-sensitive material may adhere to each other for additional use. Further, during the transportation process, abrasion with the photographic light-sensitive material causes abrasion and black powder frequently occurs, and the black powder adheres to the photosensitive layer of the photographic light-sensitive material in spots to cause a failure.

The outer layer is formed of a thermoplastic resin. This thermoplastic resin preferably contains, as a main component, various polyolefin resins which are substantially the same thermoplastic resin as the inner layer.

The polyolefin resins include the following resins.

(1) Low density polyethylene resin (LDPE) (2) Medium density polyethylene resin (MDPE) (3) High density polyethylene resin (HDPE) (4) Linear low density polyethylene resin (L-LDPE) (5) Ethylene Propylene copolymer resin (random or block copolymer resin, etc.) (6) Ethylene / butene 1 copolymer resin (7) Propylene / butene 1 copolymer resin (8) Ethylene / propylene / butene 1 copolymer resin (9) Polybutene-1 resin (10) Polystyrene resin (11) Polymethyl methacrylate resin (12) Styrene-acrylonitrile copolymer resin (13) ABS resin (14) Polypropylene resin (15) Crystalline propylene-α-olefin copolymer Polymer resin (16) Modified polypropylene resin (17) Modified polyethylene resin (18) Polypropylene / maleic anhydride graft copolymer Combined resin (19) Chlorinated polyolefin resin (mainly chlorinated polyethylene resin) (HDPE, LDPE, PE copolymer, atactic PP, etc.) (20) Ethylene / vinyl acetate copolymer resin (EVA) (21) Ethylene ionomer resin ( Resin obtained by crosslinking a copolymer of ethylene and an unsaturated acid with a metal) (22) Poly-4-methylpentene-1 resin (23) Ethylene / acrylic acid copolymer resin (EAA) (24) Ethylene / methyl acrylate Copolymer resin (EM
A) (25) Ethylene / ethyl acrylate copolymer resin (EE
A) (26) Vinyl chloride / propylene copolymer resin (27) Ethylene / vinyl alcohol resin (28) Cross-linked polyethylene resin (electron beam irradiation cross-linking, chemical cross-linking, etc.) (29) Polyisobutylene resin (30) Ethylene-chlorination Vinyl copolymer resin (31) 1,2-polybutadiene resin and the like.

The outer layer of the present invention has excellent heat-sealing properties, physical strength, abrasion resistance, moisture resistance, and the like, and has excellent L- characteristics.
It is covered with an inner layer of LDPE resin. Therefore, the above properties are deteriorated or antistatic properties, Ketjen carbon black or metal powder, carbon fiber, which is an antistatic agent or a conductive carbon black that is a conductive carbon black or a modified byproduct carbon black, which is a substance having good light shielding properties, Metal fibers, graphite, metal-plated fillers with metallized surfaces, graphite fibers, conductive zinc oxide or tin, graphite powder, carbonaceous or graphitic whisker-like short fibers, polyalkylene oxide compounds, fibrous potassium titanate, etc. Can be used. These antistatic agents, conductive powders, and conductive fibers can be used alone or as a mixture depending on the required conductivity and application. It goes without saying that the above substances can be added to the inner layer, but the addition amount is limited.

The type, shape, size, and amount of these antistatic agents and conductive substances can be appropriately selected according to the purpose of use. The base resin can also be appropriately selected according to the resin composition of the inner layer and the outer layer, but from the viewpoint of physical strength, economic efficiency (inexpensive), various polyolefin resins, especially various polyethylene resins, copolymerized polypropylene resin with α-olefin, EEA Resin, EMA resin,
EAA resin, EVA resin, ionomer resin, adhesive polymer and the like are preferable. In addition, a commercially available conductive resin for the outer layer, for example, conductive ink "Papiostat" manufactured by Tokyo Ink Co., Ltd., conductive plastic compound "Rioduct" manufactured by Toyo Ink Co., Ltd., conductive plastic manufactured by Dainippon Ink and Chemicals, Inc. It is also preferable to use commercially available pellets such as "Dielek" as they are or as blended with other resins.

Various kinds of thermoplastic resins and additives can be mixed in the outer layer as well, but the static friction coefficient is limited and therefore the addition amount and the like are limited. If the coefficient of static friction is equal to or less than that of the inner layer and it is slippery, various problems occur in the film forming process, laminating process, bag making process, and distribution process after product packaging, making it difficult to put into practical use.

When only the packaging material of the present invention is used to make a bag, the outer layer is preferably made of a thermoplastic resin having a melting point higher than that of the inner layer by 5 ° C. or higher, preferably 10 ° C. or higher. HDPE resin, for example
It is preferable to use a mixed resin of polyester resin, polypropylene resin, polyamide resin (various nylons), acrylic resin and the polyolefin resin. It is also preferable to add a light-reflecting light-shielding substance to the outer layer because heat resistance, light-shielding property, moisture-proof property, printability, appearance and the like can be improved.

The coefficient of static friction (tan θ) of the outer layer is 0.05 or more larger than that of the inner layer, and the value is 0.19 or more. If the coefficient of static friction does not satisfy such conditions, various troubles may occur in the film forming process, laminating process, bag making process, product packaging process, and distribution process due to slippage between films, and it will not be put to practical use. .

The inner layer and the outer layer are laminated by coextrusion. The adhesive strength between the inner layer and the outer layer is 10 g / 15 mm width or more. When the adhesive strength is less than 10 g / 15 mm width, delamination failure occurs in the laminating process, bag making process, heat sealing process and the like. The package having the delamination failure loses the functions required for the photographic photosensitive material package, such as light-shielding property, moisture-proof property and gas barrier property.

A light-shielding substance other than carbon black may be added to the inner layer and the outer layer. The light-shielding substance includes a light-reflecting light-shielding substance and a light-absorbing light-shielding substance.

As the light-reflecting light-shielding substance, metal powder, metal flakes, metal fibers, white pigments and the like are used. The metal powder is a metal powder formed, and is preferably an aluminum powder or an aluminum paste from which low-volatile substances are removed. Here, the aluminum powder is formed by forming molten aluminum into a powder by an atomizing method, a granulating method, a rotary disc dropping method, an evaporation method, or the like. Since the aluminum powder alone is unstable, various known treatments for inactivating the surface of the aluminum powder are performed. As a known method for producing a metal powder for filling synthetic resin, there is a method described in JP-A-59-75931.

Further, the aluminum paste is a paste in the presence of mineral spirits and a small amount of higher fatty acids such as stearic acid or oleic acid when producing aluminum powder by a known method such as a ball mill method, a stamp mill method or an atomizing method. It was made in.

The packaging material of the present invention may be composed of only a two-layer extrusion film at the same time, but it can also be used as a composite film by laminating other flexible sheet layers.

Other flexible sheet layers used in composite films include various types of thermoplastic resin films that are unstretched and uniaxially molecularly oriented, biaxially molecularly oriented, such as various polyethylene resins, ethylene copolymer resins, polypropylene resins, polychlorinated resins. There are known films of vinyl resin, polyvinylidene chloride resin, polyamide resin, polycarbonate resin, polyester resin and the like, and films of modified resins thereof. In addition, metal thin film processed film (typically aluminum vacuum deposited film), aluminum vacuum deposited paper, cellulose acetate film, cellophane, polyvinyl alcohol film, various papers, various metal foils (typically aluminum foil), non-woven fabrics Also, well-known flexible sheet layers such as a warif, a perforated film and a foamed sheet of polyethylene, polystyrene, polypropylene, polyurethane and the like are suitable.

When making a composite film, it is moisture-proof to arrange the inner layer of the two-layer coextrusion film at the innermost layer in contact with the product,
It is essential for ensuring heat sealability.

The composite film can be formed by any known adhesion method, but the dry lamination method and the extrusion lamination method are particularly preferable.

Particularly preferred adhesives used in the extrusion laminating method are, more specifically, various polyethylene resins, polypropylene resins, polybutylene resins, polymers made of polyolefin resins such as ethylene resins and ethylene copolymers {EVA, EMA, EEA resin, etc. Like L-LDPE resin, ethylene partially copolymerized with other monomers (for example, α-olefin, etc.), ionomer resin (ionic copolymer) such as Surlyn of Dupont and Hiramin of Mitsui Polychemicals And Mitsui Petrochemical Co., Ltd. Admer (adhesive polymer)}.

These adhesives preferably have a melting point of 5 ° or more lower than that of the flexible sheet 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 6 μm to 50 μm, preferably 10 μm to 20 μm, but the cost, laminating speed,
Since it is determined based on the total thickness of the laminate, etc., it is not particularly limited to this value.

The photographic light-sensitive material includes a silver halide photographic light-sensitive material, a diazo photographic light-sensitive material, a diazo type photosensitive recording material, a photosensitive resin, a self-developing photographic light-sensitive material, a diffusion transfer type photographic light-sensitive material and the like.

When the packaging material of the present invention is applied to the above-mentioned photographic light-sensitive material, one of a flat bag, a double flat bag, a square bottom bag, a self-supporting bag, a single caset bag, a double caset bag, a film sheet, and a moisture-proof box Any known form such as sticking or leader paper is possible.

The bag-making method is a conventionally known plastic film sealing method such as heat sealing, impulse sealing, ultrasonic sealing, or high-frequency sealing depending on the properties of the laminated film used. In addition, it is also possible to make a bag by using an appropriate adhesive or pressure-sensitive adhesive.

[Action]

In the packaging material for a photographic light-sensitive material of the present invention, the inner layer has a light-shielding property,
Excellent in product insertability, anti-blocking property, anti-peeling property, moisture resistance, and gas barrier property. Further, it is excellent in heat sealability (hot tackiness, foreign matter sealability, heat seal strength, etc.), is excellent in maintaining time-dependent seal strength, and is also extremely excellent in physical strength. Therefore, even if a resin having a low physical strength is used for the outer layer, the physical strength of the packaging material as a whole is increased due to the inner layer.Therefore, an antistatic light-shielding substance such as carbon black is used for the outer layer.
Add 10 wt% or more, antistatic property, peeling antistatic property,
It is also possible to greatly improve the light-shielding property.

The outermost layer has a static friction coefficient of 0.05 or more than that of the innermost layer, and the value is 0.19 or more for slippage between packaging materials such as film forming process, laminating process, bag making process, and physical distribution process after product packaging. Prevents various troubles that occur.

By using a thermoplastic resin having a high melting point in the outer layer or adding various additives, heat resistance is improved and suitability for automatic bag making is improved. Further, when a reflective light-shielding substance is added, heat resistance, light-shielding property, appearance, printability, and front / back distinguishability of the packaging material in the photographic photosensitive material packaging process under safelight can be improved.

〔Example〕

A first embodiment of the packaging material for a photographic light-sensitive material according to the present invention
It will be described with reference to the drawings.

FIG. 1 is a partial sectional view of a packaging material for a photographic light-sensitive material.
This example has the most basic layer structure, and is composed only of a simultaneous two-layer coextrusion film 3a including an inner layer 1a and an outer layer 2.

FIG. 2 is also a partial cross-sectional view of another example of the packaging material for a photographic light-sensitive material. This example is composed only of a simultaneous two-layer coextrusion film 3a including an inner layer 1a and a light-shielding outer layer 2a to which a light-absorbing light-shielding substance is added.

FIG. 3 is also a partial cross-sectional view of another example of the packaging material for a photographic light-sensitive material. In this example, the flexible sheet layer 5 is formed on the simultaneous two-layer coextrusion film 3a shown in FIG.
Are laminated.

Incidentally, FIG. 4 is a partial cross-sectional view of a comparative product, which is composed only of the light-shielding L-LDPE resin layer 6a formed of the same resin composition except that the inner layer 1a of the present invention and no lubricant are added. Is.

Next, the results of comparing the characteristics of the products I and II of the present invention, the comparative product I, and the conventional products I and II will be described.

The product I of the present invention corresponds to the embodiment of FIG. The inner layer 1a has a thickness of 100 μm, α-olefin is 4-methylpentene-1 L-LDPE resin Mitsui Petrochemical Co., Ltd. Ultzex 2021L 96.3% by weight, furnace carbon black 3% by weight, An oleic acid amide lubricant, Armoslip CP manufactured by Lion Akzo Co., Ltd., is formed with a resin composition of 0.07% by weight. The outer layer 2a has a thickness of 50 μm and contains 60% by weight of carbon black-containing conductive resin NUC-6078 manufactured by Nippon Unicar Co., Ltd., 30% by weight of HDPE resin HiZex 3300F manufactured by Mitsui Petrochemical Co., Ltd., and Mitsui Petrochemical ( stock)
It is formed of a resin composition obtained by blending 10% by weight of Ultzex 3021L manufactured by Ultzex.

The product II of the present invention corresponds to the embodiment shown in FIG. Inner layer 1a is thick
It is 100 μm, which is the same resin composition as the product I of the present invention.
The outer layer 2a has a thickness of 50 μm and is formed of a resin composition obtained by blending 70% by weight of carbon black-containing conductive resin NUC-6078 manufactured by Nippon Unicar Co., Ltd. and 30% by weight of ULTOZEX 3021L manufactured by Mitsui Petrochemical Co., Ltd. Has been done.

Comparative product I corresponds to the example in FIG. 4, has a thickness of 150 μm, and is L-LDP.
E-resin α-olefin is 4-methylpentene-1
Made by Mitsui Petrochemical Co., Ltd. Ultzex 2021L 80% by weight
And Nippon Unicar Co., Ltd. NUC polyethylene-LL0171, 17
% By weight, furnace carbon black manufactured by Mitsubishi Kasei Co., Ltd.
44B is formed with a resin composition of 3% by weight.

The conventional product I corresponds to the embodiment shown in FIG. 5 and has a thickness of 150 μm.
And LDPE resin DFD-011, made by Nippon Unicar Co., Ltd., 97% by weight
And Mitsubishi Kasei Co., Ltd. furnace carbon black 44B
(Registered trademark) It is formed with a resin composition of 3 weights.

The conventional product II corresponds to the embodiment of FIG. 6, and the LDPE resin light-shielding film layer 7a having the same resin composition as the conventional product I and having a thickness of 50 μm has a thickness of 7 μm with the LDPE extrusion adhesive layer 4 having a thickness of 15 μm.
m aluminum foil layer 8 is laminated. Then, as the flexible sheet layer 5, 35 g / m ² of stencil base paper is used as an LD with a thickness of 15 μm
It is laminated with PE extrusion adhesive layer 4 and further conventional product I
LDPE resin light-shielding film layer with the same resin composition and a thickness of 50 μm
It is a packaging material composed of a laminated film having a 7-layer structure in which 7a is laminated with an LDPE extrusion adhesive layer 4 having a thickness of 15 μm.

The results of comparing the characteristics of the present invention products I and II, the comparative product I, and the conventional products I and II are shown in Table I below.

[Effect of the invention] Since the present invention is configured as described above, physical strength in the inner layer,
Moisture-proof property, gas barrier property, heat seal property, etc. can be sufficiently secured. Further, the outer layer is not required to have sufficient physical strength and the like because the inner layer secures it, and a large amount of antistatic substance can be added to improve the antistatic property.
Therefore, the packaging material as a whole has good physical strength, antistatic properties, and the like, and can be significantly thinned to be provided at a low cost.

[Brief description of drawings]

1 to 3 are partial cross-sectional views of the packaging material which is an embodiment of the present invention. FIG. 4 is a partial sectional view of a comparative product. 5 and 6 are partial cross-sectional views of conventional packaging materials. 1 ... inner layer, 2 ... outer layer, 3 ... simultaneous two-layer coextrusion light-shielding film, and a means containing a light-shielding substance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location G03C 3/00 565 W 8910-2H G 8910-2H

Claims (3)

[Claims] 1. A copolymer of ethylene and α-olefin, having a melt index of 0.4 to 30 g / 10 minutes and a density of 0.870.
~ 0.940g / cm ³ linear low density polyethylene resin 30 ~ 9
9.49% by weight, carbon black 0.5 to 10% by weight, and lubricant 0.01 to 1.00% by weight, which is a heat seal layer having a static friction coefficient of 0.12 to 0.37, and a static friction coefficient formed from a thermoplastic resin. A photograph characterized by comprising a simultaneous two-layer coextrusion light-shielding film consisting of an outer layer having a value of 0.05 or more and an absolute value of 0.19 or more, and the adhesive strength between the inner layer and the outer layer being 10 g / 15 mm width or more. Packaging material for photosensitive materials 2. The packaging material for a photographic light-sensitive material according to claim 1, wherein the linear low-density polyethylene resin comprises a copolymer of ethylene and an α-olefin having 6 or more carbon atoms. 3. The packaging material for a photographic light-sensitive material according to claim 1, wherein the thermoplastic resin in the outer layer contains 30% by weight or more of various polyolefin resins.