JPH0677134B2 - Packaging bag for photographic material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a packaging bag for photographic light-sensitive materials, and more particularly to a packaging bag that requires physical strength and the like such as heavy goods and goods with sharp edges. .

[Conventional technology]

Various types of packaging bags are widely used,
Various performances are required according to its usage. The properties required for many packaging bags such as photographic light-sensitive materials are that they are not easily broken, they do not curl easily, they have high impact strength, they are flexible, they do not easily generate static electricity, and they are heat-sealed for sealing. Easy to do, moisture proof,
It has a gas barrier property. Without lowering the properties such as cushioning, flatness, and sliding properties,
By realizing an inexpensive packaging bag that excels in tear strength, gelbotest strength, drop strength, impact strength, curl-resistant, and can be sealed, the product is conventionally sealed in a moisture-proof bag and then transferred in a metal sealed container. It is possible to develop new applications, such as replacing the packaging of photographic light-sensitive materials that was previously done with only the packaging bag of the laminate.

Further, not only can the moisture resistance and gas barrier property suitable for the purpose be controlled, but many practical benefits such as weight reduction of packaging and prevention of breakage can be considered.

Conventionally, as such a packaging bag, for example, a 7-layer structure bag shown in FIG. 13 has been used. In this packaging bag, a light-shielding LDPE resin layer 19 containing carbon black in a high-pressure low-density polyethylene (hereinafter referred to as LDPE) resin, a metal foil layer 20, a heat-resistant flexible sheet layer 5, and a light-shielding LDPE resin layer 19 are sequentially bonded. It is formed by stacking layers 4.

[Problems to be solved by the invention]

However, the conventional packaging bag having such a structure is not sufficient in heat seal strength, tear strength, impact perforation strength and the like. Also, in the case of heavy photographic light-sensitive materials with sharp edges such as photographic roll film, the innermost light-shielding LDPE resin layer is scraped off by the photographic light-sensitive material, resulting in pinholes or light-shielding substances. It sometimes adhered to the photosensitive material.

An object of the present invention is to solve the above problems, to provide a packaging bag for a photographic light-sensitive material, which has a good heat-sealing property, a large physical strength, and is less likely to be scraped even when rubbed by the photographic light-sensitive material. And

[Means for solving problems]

The present invention has been made to achieve the above object, and as a result of earnest research, a polyethylene resin layer formed using a polyethylene resin having a predetermined density or more to have a predetermined Young's modulus or more has a sharp It was completed by first discovering that it is strong against edges.

That is, the packaging bag for the photographic light-sensitive material of the present invention has a density of 0.
Innermost layer on the side of photographic light-sensitive material containing a light-shielding substance having a Young's modulus of 50 kg / mm ² or more and a thickness of 35 μm or more, which is formed of polyethylene resin having a melt index of 930 g / cm ³ or more and a melt index of 0.2 to 3.0 g / 10 min. A polyethylene resin layer, a void sheet layer having a density of 0.92 g / cm ³ or less and a thickness of 60 μm or more laminated on the polyethylene resin layer, and a light-shielding substance laminated on the void sheet layer at 0.1 to 20 g / ; and a flexible sheet layer that is not uniaxial molecular orientation comprises m ^2, and includes a light-shielding material as a whole laminate 0.5 g / m ² or more, the compression ratio of the laminate is from 15 to 75% It is configured as a feature.

The polyethylene-based resin layer is formed of a polyethylene-based resin which is a medium-density polyethylene resin, a high-density polyethylene resin, or a linear low-density polyethylene resin, alone or as a mixed resin with another thermoplastic resin. When it is formed of a mixed resin, it is necessary that the total of various polyethylene resins is a majority from the viewpoint of physical strength and suitability for bag making.

This polyethylene resin must have a density of 0.930 / cm ³ or more, and a melt index (hereinafter referred to as MI) of 0.2 to 3.0 g / 10 minutes.

When the melt index is less than 0.2 g / 10 minutes, not only the film formability is a problem, but also when a light-shielding substance such as carbon black is added, molecular orientation tends to occur and there is a problem in physical strength.

If the melt index exceeds 3.0 g / 10 minutes, the film formability will be improved, but the abrasion resistance will deteriorate, and it will be easily scraped when rubbed with a photographic light-sensitive material.

If the density is less than 0.930 g / cm ³ , the degree of crystallinity is small and molecular orientation is difficult to occur, so that the abrasion resistance of the polyethylene resin layer is small, the coefficient of static friction is large, and tearing easily occurs when the product is put into a bag. Further, it is difficult to set the Young's modulus to 50 kg / mm ² or more.

The polyethylene resin layer must have a Young's modulus of 50 kg / mm ² or more and a thickness of 35 μm or more. If the Young's modulus is less than 50 kg / mm ² and the product is a photographic roll film with a sharp edge and the weight is 3 kg or more, if one part of the film sticks out due to film winding misalignment, it may be photographed during transportation or in a bag. Tear occurs when inserting a roll film or the like.

Further, if it is easier to stretch than the void sheet layer or the flexible sheet layer, curling becomes large when the adhesive layer is laminated with these layers, and bag-making property becomes a problem.

If the thickness is less than 35 μm, the tensile strength is insufficient and curling becomes large when laminated with the void sheet layer or the flexible sheet layer, and wrinkles or cuts are likely to occur, which makes practical application difficult.

Also, when a heavy product is put in a packaging bag and the thickness is less than 35 μm, it is difficult to put it into practical use because it has holes due to its sharp edges.

The polyethylene resin layer can be used as a single film layer, a simultaneous multi-layer coextrusion film layer, a non-stretched film layer, a uniaxial molecular orientation film layer, or a biaxial molecular orientation film layer, as long as the above properties are satisfied. Especially MI
(Melt index) 0.3-1.5g / 10 minutes and density 0.95
High density polyethylene resin with g / cm ³ or more and a density of 0.935 g /
A molecularly oriented film layer using a linear low-density polyethylene resin having a size of about cm ³ is preferable. Further, using a high density polyethylene resin having a density of 0.950 g / cm ³ or more, the blow ratio is 1.2 or more, preferably the blow ratio is 1.6 or more, and particularly the blow ratio is
A reinforced inflation film of 2.0 or more is preferable because it does not break even with abrasion resistance and sharp edges and is inexpensive.

The polyethylene resin layer may contain a light-shielding substance such as carbon black. However, as a result of research, it became clear for the first time that the surface of the polyethylene resin layer may be scraped by an extremely sharp edge, and in such a case, it is preferable to add a lubricant without adding carbon black. On the other hand, the flexible sheet layer, which will be described later, is not affected by the sharp edges of the photographic roll film and is not damaged. Therefore, it is essential to add a light-shielding substance.

The uniaxial molecular orientation film also includes a film in which the molecular orientation rate in the molecular orientation direction is 1.5 times or more higher than the molecular orientation rate in the 90 degree direction. For example, an inflation film having a blow ratio of 2 and stretched 3 times in the vertical direction is a vertical uniaxial 3 times stretched film.

In addition, a uniaxially stretched film (horizontal uniaxially stretched film by a tenter, longitudinal uniaxially stretched film) is generally used as the uniaxially molecularly oriented film, but in the present invention, physical shaping or blown ratio of an inflation film (tubular film) or the like is used. A flat film in a state where it is made smaller and molecularly oriented, or is strongly molecularly oriented in the longitudinal direction and is spirally cut and spread to form an oblique (for example, 45 °) molecular orientation is also called a uniaxial molecular orientation film. As an example of a known method for producing a uniaxial molecular oriented film (including a uniaxially stretched film), JP-A-47-34656, JP-A-48-100464 and JP-B-40-5319 are cited.
No. 47, No. 47-38621, No. 47-39927, No. 53-1
There is an 8072 publication.

The molecular orientation may be vertical, horizontal, or diagonal, but the diagonal uniaxial molecular orientation film layer is preferable in that the difference between the Young's modulus of vertical and horizontal, the maximum strength, and the maximum elongation ratio is small.

Further, the molecular orientation rate and the stretching ratio are selected according to the resin component and the application of the product and are not particularly limited, but the effect of stretching becomes clear when the stretching ratio is 2 to 15 times, and the light-shielding substance In the case of containing, the stretch ratio is particularly preferably in the range of 2 to 6 from the viewpoint of film quality such as heat sealability and generation of fish eyes.

As the void sheet layer, various papers, for example, kraft paper,
It is possible to use various types of non-woven fabrics such as high-quality paper, stencil base paper, photographic paper base paper, light-shielding paper, spunbonded non-woven fabric, synthetic paper, woven fabric or knitted fabric. Unbleached kraft paper, Kurpac paper, Duostress paper and the like are preferable because they are inexpensive and have a large cushioning effect and physical strength improving effect. Further, as the void sheet layer, a foamed sheet which is expensive and inferior in the laminating process suitability and bag making suitability but which is a packaging bag excellent in cushioning property, physical strength and heat insulating property can be used.

The void sheet layer has a density of 0.92 g / cm ³ or less and a thickness of 6
It is 0 μm or more. If the density exceeds 0.92 g / cm ³ , the area of the space will be insufficient, and the cushioning property will be insufficient, and the effect of preventing bag tearing will be reduced. In addition, it is difficult to put into practical use because the cost becomes high.

When the thickness is less than 60 μm, the cushioning effect is almost lost, and most of the impact is directly transmitted to the polyethylene resin layer, so that bag breakage is likely to occur. The foamed sheet used for the void sheet layer is, for example, various polystyrene and various polypropylene, various polyethylene, olefin polymers such as polybutene, or ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-vinyl acetate copolymer. , Olefin-based copolymers such as ethylene-acrylic acid ester copolymers, copolymers containing ethylene as a main component such as chlorinated polyethylene, copolymers containing propylene as a main component, or polyamide, polyacetal, polycarbonate, polyphenylene 1 or 2 such as oxide
In addition to thermoplastic resin foam sheets such as mixtures of one or more types, polyurethane, natural rubber (sponge-like products made from undiluted latex of rubber), foam rubber sheets such as SBR, or other plastics containing these as the main components And a mixture with rubber and the like. Preferred foam sheets to which the method of the present invention can be effectively applied are substantially polystyrene, high-density, medium-density, low-density polyethylene, low-pressure low-density polyethylene (L-LDPE), and polypropylene-based thermoplastic resin. It is a foamed sheet.

This thermoplastic resin also includes modified, crosslinked, and radiation-irradiated resins. Typical examples of commercially available foamed sheets include "foamed polyethylene sheet" such as Hi-sheet Industry's high sheet, Sekisui Chemical's Softlon S, Literon S, Tokyo Kasei's Cell Hope, Asahi Dow's Esaform S,
Nippon Styrene Paper Miramat, Furukawa Electric Foam Ace L, Hitachi Chemical Fine Cell, Sanwa Chemical PE Sun Foam, MTB Chemical PE Light, Toray's Trepef PP, Mitsui as "foam polypropylene sheet"Tohatsu's Hatsport, "Expanded polystyrene sheet" includes Asahi Dow's Styrofoam, Nippon Styrene Paper's styrene paper, Sekisui Kasei's Eslen sheet, Corpar's Corpearl, Kanebuchi Kaganefan, etc. There is Nippi form of Nippi. In particular, expanded polystyrene sheet (expanded polystyrene paper) and expanded polyethylene sheet are preferable in terms of cost and characteristics. The expansion ratio has a large effect on cushioning properties, slip characteristics, and mechanical strength, so it is selected according to the application of the product, but it is 2 to 50 times (more preferably 10 to 30 times).
Fold) is appropriate. When it is 50 times or more, the strength of the foam itself is largely reduced, which causes delamination. When the amount is less than 2 times, the gelbotest strength is lowered in impact resistance, other properties also lose the effect as a foam, and it is close to a general film at a high cost.

When laminating the foamed sheet layers, not only are they simply laminated by adhesion, but the boundary surfaces of the foamed sheet layers are partially melted and compressed so that the thickness of the laminated body after lamination is smaller than the theoretical sum of each layer. It is important to have a curved shape. However, the central part of the foamed sheet layer should not be completely melted and compressed, and the voids should not be largely eliminated.

Therefore, the compressibility of the laminated body = (1-thickness of laminated body / theoretical sum of thickness of each layer) × 100 is 15 to 75%, preferably 30 to 65%
The residual thickness ratio is preferably 85 to 25%, preferably 70 to 35%.

By compressing the laminate in this manner, as compared with a simple laminate of three layers of the same type, interlayer peeling prevention, curl reduction, flexibility improvement, heat sealability improvement, laminate production suitability improvement,
Features such as preventing wrinkles, reducing thickness unevenness, reducing winding thickness, and increasing winding length are exhibited. If this compression rate is less than 15%, delamination occurs, heat sealing is difficult, and because it does not fold, it is not suitable for sealing and packaging work, and wrinkles, uneven thickness, winding thickening etc. I have a problem with. Further, if the compression ratio exceeds 75%, there are disadvantages such as reduction of gel votest strength, impact strength, and tear strength.

As the flexible sheet layer that is not uniaxially molecularly oriented (hereinafter referred to as flexible sheet layer), paper, thermoplastic resin film, or the like is used. When the thermoplastic resin film is used, it may be an unstretched film or a biaxial molecular orientation film, and it is not necessary to laminate the innermost polyethylene resin layer so that the molecular orientation axis intersects. Further, it was found that the LDPE resin film layer or the L-LDPE resin film layer may be used without particularly requiring abrasion resistance, and there is no need to use a high density polyethylene resin film layer.

This flexible sheet layer contains 0.1-20g of light-shielding substance.
/ m ² included. This is to secure the light-shielding property and antistatic property, which are essential as a packaging bag for photographic light-sensitive materials.

In particular, when the light shielding substance is not added to the polyethylene resin layer and the flexible sheet layer, the object of the present invention is not achieved unless 0.5 g / m ² or more of the light shielding substance is added to the flexible sheet layer.

In addition, the light-shielding substance is used in the entire laminated body forming the packaging bag.
It is necessary to contain 0.5g / m ² or more. When the amount of the light-shielding substance contained in the entire laminate is less than 0.5 g / m ² , the complete light-shielding property and antistatic property, which are essential for packaging bags for photographic light-sensitive materials, cannot be secured.

As long as the light-shielding substance is contained in the entire laminate in an amount of 0.5 g / m ² or more, it may be contained only in the flexible sheet layer or may be contained in each layer. The light-shielding substance refers to all substances that do not transmit visible light and ultraviolet rays, but representative examples include various types of carbon black, aluminum powder, color pigments, aluminum paste, titanium oxide, barium sulfate, calcium carbonate, clay, etc. White pigments, various metal powders, various metal fibers and the like. From the viewpoints of quality, cost and light-shielding ability, various carbon blacks, aluminum powders, and aluminum pastes from which low volatile substances have been removed are preferable for packaging of photographic light-sensitive materials.
In particular, furnace type carbon black has a pH of 7
When L + LDPE resin film with a particle size of ± 2 and particle size of 35μm or less is added to the L-LDPE resin film, it has the property of improving rather without lowering the strength. Furthermore, the occurrence of fogging and the solidification of carbon black. It is preferable because there are few (bugs) and fish eyes.

The light-shielding substance may be a powder colorant, a paste colorant, a wet colorant, a masterbatch, a dye / pigment, or a colored pellet, depending on the resin used, the machine used, the cost, and the like.

Typical examples of the classification of carbon black, which is a typical light-shielding substance used in the present invention, by the raw material include gas black, oil furnace black, anthracene black, acetylene black, oil smoke, pine smoke, animal black, vegetable black and the like. In the present invention, light-shielding property, cost,
Furnace carbon black is preferable for the purpose of improving physical properties, and acetylene carbon black and Ketjen carbon black are preferable as the light-shielding substance having an antistatic effect, which is expensive. If necessary, it is also preferable to mix the former and the latter according to the required characteristics. Although there are various forms of blending the light-shielding substance with the polyethylene-based polymer as described above, the masterbatch method is preferable in terms of cost, prevention of contamination of the workplace, and the like. In Japanese Patent Publication No. 40-26196, which is a known document, a method of dispersing a carbon black in a solution of a polymer dissolved in an organic solvent to prepare a polymer-carbon black masterbatch is disclosed in Japanese Patent Publication No. 43-10382. Describes a method of dispersing carbon black in polyethylene to form a masterbatch.

Lamination of the polyethylene resin layer, the void sheet layer and the flexible sheet layer is performed by adhering each layer with various adhesives. The adhesive, as a hot melt adhesive, various polyethylene resins, polypropylene resins, polyolefin-based thermoplastic resins such as polybutene resin hot melt adhesive, ethylene-propylene copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene- Examples include olefin copolymer resins such as acrylic ester copolymer resins, thermoplastic resins such as ionomer resins, hot melt adhesives, other hot melt type rubber adhesives, solvent type rubber adhesives and the like. When a foamed sheet is used as the void sheet layer, it is important to partially melt-compress the surface layer of the foamed sheet, not to simply bond it with an adhesive.

Polyolefin-based resin adhesives include, specifically, various polyethylene resins, polypropylene resins, polybutylene resins and other polyolefin resins and ethylene-acrylic acid ester resins and other copolymer resins with ethylene, as well as low-pressure low-density polyethylene (L-LDPE). Like resins, some other monomers other than ethylene are copolymerized, Surlyn from Dupont, ionomer resins (ionic copolymers) such as Himilan from Mitsui Polychemicals, and Mitsui Petrochemical Co., Ltd. Including Admer etc. Typical examples of known solvent-based adhesive coating methods for melt-bonding with another solvent-based adhesive include, for example, dip coating, spray coating, air knife coating, curtain coating, and roller coating. Method, doctor coating method, wire bar coating method, slide coating method, gravure coating method or extrusion coating method using a hopper described in US Pat. No. 2,681,294. U.S. Pat.No. 2,761,791,
No. 2,941,898, No. 3,508,947, Shinji Harasaki, "Coating Engineering," p. 253 (published by Asakura Shoten in 1973), etc., it is also possible to apply two or more layers at the same time. An appropriate method can be selected depending on the amount and the coating speed.

It is preferable that the surface of each layer to which the adhesive layer is applied is subjected to a surface activation treatment by a known method before laminating another layer.

As a method of surface activation treatment, anchor coat treatment,
Although an acid etching treatment, a gas burner flame treatment, a corona discharge treatment, a glow discharge treatment, or the like is used, from the viewpoint of cost or simplicity, US Pat.
No. 2,715,075, No. 2,848,727, No. 3,54
The corona discharge treatment described in the specifications of 9,406 and 3,590,107 is used.

The packaging bag of the present invention can be formed by laminating various flexible sheet layers. For example, by laminating flexible sheets such as various papers, non-woven fabrics, cellophane, etc., it is possible to improve heat sealing property, strength, slip property, antistatic property, printability, light shielding property, aesthetics and the like. Conceivable.

In particular, if the outermost layer of one side is a heat-resistant flexible sheet layer that is non-heat-melting like paper, or if it has a higher melting point than the polyethylene resin layer on the heat-sealing side by 10 ° C or more, the low melting point side for the polyethylene resin layer It becomes easier to heat-seal each other, which is advantageous for producing a bag having excellent heat-sealing property.

A method for laminating another known flexible sheet on the laminate of the present invention may be an ordinary method, for example, a thermal bonding method (hot plate bonding method, impulse bonding method, ultrasonic bonding method), a method using an adhesive (wet lamination). Method, dry laminating method, hot melt laminating method, extrusion laminating method), coextrusion extrusion laminating method and the like are used.

On the polyethylene resin layer and the flexible sheet layer, it is preferable to laminate a film layer using a thermoplastic resin to which various lubricants are added so that a sharp edge of a photographic roll film or the like is slippery.

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) Silicone lubricants; various grades of dimethylpolysiloxane, carboxyl-modified silicone oil, (Shin-Etsu silicone, Toray silicone, etc.) (2) Oleic acid amide lubricants: Armoslip CP (Lion Akzo), Neutron (Nippon Seika) ), Neutron E-18 (Nippon Seika), Amide O (Nitto Kagaku), Alfuro E-10 (Nippon Yushi), Diamid O-200 (Nippon Kasei), Diamid G-200 (Nippon Kasei), etc. ( 3) Erucamide amide lubricant; Alflo P-10 (Nippon Oil & Fats), etc. (4) Stearic acid amide lubricant; Alflo S-10 (Nippon Oil and Fats), 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
There is TS-2 (Kao soap) etc.

The packaging bag for the photographic light-sensitive material of the present invention is a single flat bag, a double flat bag,
Square-bottomed bags, free-standing bags, single gusset bags, double gusset bags, and all other forms of bags are 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 laminate used. In addition, it is also possible to use appropriate adhesives, pressure-sensitive adhesives, etc. for bag making.

The photographic light-sensitive materials include silver halide photographic light-sensitive materials, diazo photographic light-sensitive materials, photosensitive resins, self-developing photographic light-sensitive materials, diazo heat-sensitive recording materials, diffusion transfer photographic light-sensitive materials, black and white,
Includes all types of photographic materials, regardless of color.

[Action]

In the packaging bag for a photographic light-sensitive material of the present invention, even if the polyethylene resin layer is rubbed by a sharp edge of a photographic roll film or the like, the surface thereof is hardly scraped. Therefore, even if the packaging bag is torn or the carbon black or the like is added to the polyethylene resin layer, the photographic light-sensitive material is less likely to be soiled under the influence of the carbon black. Further, by combining the void sheet layer and the flexible sheet layer, physical strength, moisture resistance, light shielding property, etc. are secured.

〔Example〕

Examples of the packaging bag for photographic light-sensitive materials according to the present invention will be described.

1 to 4 are cross-sectional views of a laminate used for a packaging bag for photographic light-sensitive materials.

In the laminate shown in FIG. 1, a polyethylene resin layer 1a to which a light-shielding substance is added is provided as the innermost layer on the side of the photographic light-sensitive material.
The flexible sheet layers 3 are sequentially laminated with the adhesive layer 4.

The laminated body of FIG. 2 has the same layer structure as the laminated body of FIG. 1 except that the innermost layer is the polyethylene resin 1 to which the light-shielding substance is not added.

The laminated body of FIG. 3 has a layer structure in which the heat resistant flexible sheet layer 5 is laminated on the flexible sheet layer 3 via the adhesive layer 4 in the laminated body of FIG.

The laminated body of FIG. 4 is the laminated structure of the laminated body of FIG. 1 in which the light-shielding polyethylene resin layer 1a is composed of two light-shielding coextruded film layers 6a and 7a. It is essential that 6a and 7a are the polyethylene resin layers of the present invention.

Next, an example of a mode in which the photographic light-sensitive material is packaged in a packaging bag using the above laminated body will be described with reference to FIGS.

FIG. 5 is a partially cutaway plan view showing a flat bag packaging form. This flat bag is made by stacking laminated bodies and sealing the three sides,
The seal portion 9 is adhered and hermetically sealed to form a bag.

FIG. 6 is a cross-sectional view showing a packaging form of a double bag. This 2
The heavy bag is a photographic photosensitive material 12 completely sealed by a seal portion 13 with an outer paper 10 and an inner paper 11, and the inner paper 11 is the packaging bag of the present invention.

FIG. 7 is a sectional view showing a packaging form of a double gusset bag. This double gusset bag is formed of an outer paper 10 and an inner paper 11, and the inner paper 11 is the packaging bag of the present invention.

FIG. 8 is a conceptual cross-sectional view showing a packaging form of a black and white or color roll-shaped photographic light-sensitive material (printing paper, movie film, printing film, indirect X-ray film, microfilm, etc.).

This roll-shaped photographic photosensitive material packaging bag is composed of an outer paper 10 and an inner paper 11, and the inner paper 11 uses the packaging bag of the present invention.
An adhesive 14 or an adhesive tape 15 is provided on the outer side of the seal portion 13.

9 to 12 are cross-sectional views of the laminate of the comparative product of the present invention.

The laminated body of FIG. 9 has a layer structure in which a polyethylene resin layer 1a containing a light shielding substance is laminated via an adhesive layer 4 on a polyethylene resin layer 1a containing a light shielding substance as the innermost layer.

The laminated body of FIG. 10 has a layer structure in which the perforated film layer 17 and the flexible sheet layer 3 are laminated on the innermost layer of the polyethylene resin layer 1a added with the light-shielding substance via the adhesive layer 4.

The laminated body of FIG. 11 has a layer structure in which the void sheet layer 2 and the flexible sheet layer 3 are sequentially laminated with the adhesive layer 4 on the innermost flexible sheet layer 3.

The laminated body of FIG. 12 has a layer structure in which the void sheet 2 and the polyethylene resin layer 1a containing a light-shielding substance are sequentially laminated with the adhesive layer 4 on the innermost flexible sheet 3.

Next, the experimental results comparing the characteristics of the products 1 to 5 of the present invention, the conventional product 1 and the comparative products 1 to 4 will be described.

The product 1 of the present invention corresponds to the embodiment of FIG. The innermost polyethylene resin layer 1 contains 3% by weight (2.0 g / m ² ) of furnace carbon black, Mitsui Petrochemical Co., Ltd.
A non-stretched inflation film made of HDPE resin (trade name: Hi-Zex 3300F) manufactured by K.K. The thickness is 70 μm and Young's modulus is 100 kg / mm ² in the vertical direction and 53 k in the horizontal direction.
It is g / mm ² . The thickness of the void sheet layer 2 is 500 μm
Polyethylene sheet manufactured by Nippon Styrene Paper Co., Ltd. with a density of 0.03 g / cm ³ (trade name: Miramat, expansion ratio)
30 times) was used. As the flexible sheet layer 3, an unstretched inflation film having a thickness of 50 μm and made of L-LDPE resin (trade name: ULTOZEX 2020L) manufactured by Mitsui Petrochemical Co., Ltd. containing a light-shielding substance at 14 g / m ² was used. As the adhesive layer 4, an LDPE resin extrusion laminate layer having a thickness of 15 μm was used.

The product 2 of the present invention has a thickness of 80 μm in the void sheet layer 2 and a basis weight of
This is the same as the product 1 of the present invention except that Kurupack paper having a density of 73 g / cm ² and a density of 0.90 g / cm ³ was used.

The product 3 of the present invention is a medium density L-LDPE resin (trade name: ULTOZEX 3520L) manufactured by Mitsui Petrochemical Co., Ltd. containing 3% by weight (2.0 g / m ² ) of furnace carbon black as the polyethylene resin layer 1. Young's modulus in the thickness 70μm of the unstretched made the longitudinal direction is transverse direction at 61 kg / mm ² using a blown film 80 kg / mm ^2. The other layers are the same as those of the product 1 of the present invention.

The product 4 of the present invention comprises, as the polyethylene resin layer 1, an HDPE resin (trade name Hi-Zex 5300S) manufactured by Mitsui Petrochemical Co., Ltd. containing 3% by weight (1.3 g / m ² ) of carbon black at an angle of 45 degrees. Young's modulus in the thickness 45μm was obliquely molecular orientation longitudinally transverse with 82 kg / mm ² using a film of 81 kg / mm ^2. The other layers are the same as those of the product 1 of the present invention.

The product 5 of the present invention is, as the flexible sheet layer 3, an unstretched inflation film having a thickness of 50 μm and made of HDPE resin (trade name Hi-Zex 3300F) manufactured by Mitsui Petrochemical Co., Ltd. containing 1.4 g / m ^{2 of} furnace carbon black. Using. The other layers are the same as those of the product 1 of the present invention.

Conventional product 1 corresponds to the example in FIG. Light-shielding LDPE resin layer
19 is 3% by weight of furnace carbon black
(1.4 g / m ² ) including LDPE resin (trade name DFD-0111) manufactured by Nippon Unicar Co., Ltd., unstretched thickness is 50 μm, Young's modulus is 27 kg / mm ² in the longitudinal direction and 26 kg / mm in the lateral direction. ^Two blown films were used. The thickness of the metal foil layer 20 is 7μ
m aluminum foil was used. As the heat resistant flexible sheet layer 5, bleached kraft paper having a thickness of 40 μm and a basis weight of 35 g / m ² was used. As the adhesive layer 4, an LDPE resin extrusion laminate layer having a thickness of 15 μm was used.

Comparative product 1 corresponds to the example of FIG. The polyethylene resin layer 1a is made of Mitsui Petrochemical Co., Ltd. HDPE resin (trade name Hi-Zex 5300S) containing 3% by weight (1.3 g / m ² ) of furnace carbon black, and is obliquely molecularly oriented at an angle of 45 degrees. , Thickness is 45 μm and Young's modulus is 82 kg in the vertical direction.
The film has a width of 81 kg / mm ² and a width of 81 kg / mm ² . And, it is a cross-laminated laminate in which molecular orientation axes are laminated so as to intersect each other at 90 degrees. The adhesive layer 4 has a thickness of 10 μm
Is an LDPE resin extrusion laminate layer.

Comparative product 2 corresponds to the example in FIG. The polyethylene resin layer 1a and the flexible sheet layer 3 are the same as those of the product 1 of the present invention. As the perforated film layer 17, a pan hole made of Dainippon Plastic made of LDPE resin having a thickness of 50 μm and a density of 0.926 g / cm ³ was used. The thickness of the adhesive layer 4 is 15μ
m LDPE resin extrusion laminate layer was used.

Comparative product 3 corresponds to the example in FIG. As the innermost flexible sheet layer 3, L-LDP manufactured by Mitsui Petrochemical Co., Ltd. containing 3% by weight (1.9 g / m ² ) of furnace carbon black.
Unstretched thickness 70 made of E resin (Ultzex 2020L)
Young's modulus in μm the longitudinal direction is transverse direction at 28kg / mm ² 28kg / mm ²
Blown film was used. The other void sheet layer 2, flexible sheet layer 3 and adhesive layer 4 are the same as those of the product 1 of the present invention.

Comparative product 4 corresponds to the example in FIG. As the innermost flexible sheet layer 3, L-LDP manufactured by Mitsui Petrochemical Co., Ltd. containing 3% by weight of furnace carbon black (1.9 g / m ² ).
Unstretched thickness 70 made of E resin (Ultzex 2020L)
Young's modulus in μm the longitudinal direction is transverse direction at 28kg / mm ² 28kg / mm ²
Blown film was used. The outermost polyethylene-based resin layer 1a is made of Mitsui Petrochemical Co., Ltd. HDPE resin (trade name Hi-Zex 3300F) containing 1.4 g / m ^{2 of} furnace carbon black and has an unstretched thickness of 50 μm.
m blown film was used.

Tables 1 and 2 show the results of comparing the characteristics of the products 1 to 5 of the invention, the conventional product 1 and the comparative products 1 to 4 described above. MI (ASTM D-1238 E condition) and density (ASTM D-150
5) is as follows. "HIZEX 3300F"(MI; 1.2g
/ 10 min, density; 0.954g / cm ^3), "HI-ZEX 5300S" (M
I; 0.4 g / 10 min, density; 0.964 g / cm ³ ), "Ultzex 35
20L "(MI; 2.1g / 10 min, density; 0.935g / cm ^3)," ULTZEX 2020L "(MI; 2.1g / 10 min, ^{density; 0.920g / cm 3),"} D
FD-0111 "(MI; 2.4g / 10 min, density; 0.923g / cm ³⁾ is.

(Effect of the invention) The packaging bag for a photographic light-sensitive material of the present invention has a polyethylene resin layer of the innermost layer having a density of 0.930 g / cm ³ or more and a melt index of 0.2 to 0.3 g / 10 min. But
The compression rate of the laminate is formed by forming it so that it is 50 kg / mm ² or more.
Since it is set to 15 to 75%, it will not be scraped even if it is rubbed by the sharp edge of the photographic light-sensitive material. Furthermore, since the predetermined void sheet layer and the flexible sheet layer are laminated, the physical strength is improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 4 are partial cross-sectional views of a laminate used in a packaging bag for a photographic light-sensitive material according to the present invention. FIG. 5 to FIG. 8 are views showing a form in which the photographic light-sensitive material is packaged in the photographic light-sensitive material packaging bag. 9 to 12 are partial cross-sectional views of the laminate of the comparative product. FIG. 13 is a partial cross-sectional view of a laminate used in a conventional packaging bag. 1 ... polyethylene resin layer, 1a ... light-shielding polyethylene resin layer, 2 ... void sheet layer, 3 ... flexible sheet layer, 4 ... adhesive layer.

Claims (4)

[Claims] 1. A polyethylene resin having a density of 0.930 g / cm ³ or more and a melt index of 0.2 to 3.0 g / 10 minutes,
The innermost polyethylene resin layer on the photographic light-sensitive material side having a Young's modulus of 50 kg / mm ² or more and a thickness of 35 μm or more, and a polyethylene resin layer having a density of 0.92 g /
It comprises a void sheet layer having a thickness of 60 μm or more at a cm ³ or less and a flexible sheet layer which is laminated on the void sheet layer and contains 0.1 to 20 g / m ^{2 of} a light-shielding substance and which is not uniaxially molecularly oriented, and shields light. A packaging bag for a photographic light-sensitive material, characterized in that the laminate as a whole contains 0.5 g / m ² or more, and the compressibility of the laminate is 15 to 75%. 2. The polyethylene resin layer, wherein at least the layer facing the photographic light-sensitive material is a multilayer coextrusion film layer having a density of 0.930 / cm ³ or more and a Young's modulus of 50 kg / mm ² or more. Packaging bag for photographic light-sensitive material according to item 1 3. The packaging bag for a photographic light-sensitive material according to claim 1, wherein the polyethylene-based resin layer is a diagonal uniaxial molecular orientation polyethylene-based resin layer. 4. The polyethylene-based resin layer according to claim 1, which contains 50% by weight or more of high-density polyethylene resin.
Packaging bag for photographic light-sensitive material according to item 2 or 3