JPH0272941A - Packaging material - Google Patents

Abstract

PURPOSE:To improve opening property and packaging suitability by laminating on one side of a metallic thin film worked flexible sheet with low elongation a flexible sheet with a longitudinal elongation rate not higher than that of this sheet, and on the other side a flexible sheet with a longitudinal elongation rate not lower than that of this sheet. CONSTITUTION:A metallic thin film worked flexible sheet may preferably be a uniaxial or biaxial molecular orientation film made of a main ingredient of polyester resin, polyamide resin, polypropylene resin and high density polyethylene resin. It may be most suitable for a metallic thin film worked layer to use a metal and aluminium capable of thin film mold. The paper or the oriented film laminated on one side of this sheet may preferably be higher 5 deg.C or above at the melting point thant a thermoplastic resin film, and preferably be white color or transparent. The thermoplastic resin film with high elongation laminated on the other side may preferably be a polyolefin resin film being ensured in heat seal and contained with ethylene copolymer resin or/and modified polyethylene resin of 10wt.% or more.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applicable to photosensitive materials, particularly photographic materials, photosensitive resins, and packaging bags for photosensitive materials such as foodstuffs, pharmaceuticals, dyes, etc. whose deterioration is accelerated by various types of light including ultraviolet rays, etc. Regarding packaging materials.

[Conventional technology]

There are various types of packaging bags for photosensitive materials depending on their uses, and they are widely used.

Generally required properties for packaging bags for photosensitive materials include light shielding properties, gas barrier properties, moisture proofing properties, antistatic properties, physical strength, etc., as well as ease of opening and minimal curling in order to measure packaging suitability.

Conventionally, packaging bags for photosensitive materials have been made of high-pressure low-density polyethylene (hereinafter referred to as LDPE) resin film kneaded with carbon black, or as shown in FIG. A packaging material of a laminated film, which is made by laminating the above and the like using an adhesive layer 5, has been used.

Also, recently, a vacuum-deposited aluminum flexible sheet has been proposed in place of aluminum foil.

The present inventor also conducted extensive research to improve packaging bags for photosensitive materials, and installed a linear low-density polyethylene (hereinafter referred to as L-LDPE) resin film with a small thickness difference on both sides of a metallized film with a difference in adhesive strength. proposed a laminated film with high physical strength and low curl, which is laminated with a certain adhesive layer (Japanese Patent Application Laid-Open No. 54934/1983).

In addition, we proposed a laminated film with improved physical strength by combining two layers of uniaxially stretched films.
JP-A-59-201848), and further proposed a laminated film with high physical strength and low curling, in which uniaxially oriented thermoplastic resin films are laminated on both sides of a foam sheet (Japanese Patent Laid-Open No. 59-201848).

In addition, we proposed a packaging bag using a packaging material made of an L-LDPE resin film, which has high physical strength and excellent heat-sealability, and is made of a resin composition in which carbon black is added to L-LDPE resin (Japanese Patent Laid-Open No. 1983-1991). -151045
No. 60-189438, Japanese Patent Application Laid-Open No. 1987-189438
(No. 489936, Japanese Unexamined Patent Publication No. 18547/1983)
.

Furthermore, an easy-to-open packaging material for photographic materials is disclosed in Japanese Utility Model Application Publication No. 62-41531, and the easy-to-open packaging material for photographic materials is made of an LDPE resin light-shielding heat film, anchor-coated aluminum foil, and a heat-resistant flexible sheet. proposed a flexible packaging material.

[Problem to be solved by the invention]

However, the conventional LDPE resin film and the
The packaging material made only of L-LDPE resin film proposed in Publication No. 1-189936 has insufficient moisture and gas barrier properties even if it is thick, and has problems with easy opening, and also has poor antistatic properties. However, it has been difficult to ensure sufficient quality for high-sensitivity photographic materials or photographic materials containing dyes that deteriorate due to oxygen or moisture. As a countermeasure to this problem, a laminated film made by laminating L-LDPE resin film, aluminum foil, and paper using an LDPE resin extrusion laminate adhesive layer has a large amount of curling.
Although it has excellent physical strength, it has problems in terms of ease of opening and also has the disadvantage of being expensive.

When an aluminum vacuum-deposited flexible sheet was used instead of aluminum foil, curling was extremely large and packaging suitability was poor.

In addition, as an improvement measure, we proposed Japanese Patent Application Laid-Open No. 61-5493.
Although the laminated film of Publication No. 4 has excellent physical strength, it has problems with ease of opening and is more expensive. sex was still insufficient. Japanese Patent Application Publication No. 5
The cross-laminated films disclosed in JP-A No. 7-6754 and JP-A-59-201848 have very good physical strength, but have problems with easy opening, and also have poor moisture resistance, gas barrier properties, antistatic properties, etc. However, it is insufficient as a packaging material for high-sensitivity films, is expensive, and has problems with curling and heat sealability.

Although these conventional packaging materials have very good physical strength, they all have problems with the ease of opening the packaging bag, so it is necessary to either fold the product entry/exit part as is and tape it, or seal it with heat sealing etc. In some cases, it is necessary to use scissors or a cutter to open the package, which is dangerous when working in a darkroom and can damage the product. Also, in 1987
The easy-open packaging material for photographic materials disclosed in Japanese Patent No. 41531 had pinholes in heavy products with sharp edges, and the heat sealing strength decreased over time.

The present invention solves the above problems and is inexpensive, has excellent bag opening properties despite its high physical strength, has excellent appearance, light shielding properties, moisture proofing properties, gas barrier properties, heat resistance, heat sealing suitability, and heat sealing strength over time. It is an object of the present invention to provide a packaging material that has excellent antistatic properties, less curling, and is suitable for packaging.

[Means to solve the problem]

The present invention has been made to achieve the above-mentioned object, and the present invention has been made by applying an adhesive layer to one side of a flexible sheet processed with a thin metal film, which has a relatively low elongation, so that the elongation percentage in the longitudinal direction is less than that of the flexible sheet processed with a thin metal film. The problem was solved by using a laminated film in which flexible sheets having a metal F3uJ process were laminated, and a film having a longitudinal elongation percentage higher than the metal F3uJ processed flexible sheet was laminated on the other side.

That is, the present invention is a laminated film in which paper, stretched film, or cellophane is laminated to one side of a metal thin film processed flexible sheet, and a thermoplastic resin film is laminated to the other side by an adhesive layer, and the laminated film has the above-mentioned structure. The relationship between the longitudinal elongation percentage of the material (E,, Eo, Eo), ES, and town is (EPSED, Eo)≦ES≦EF big, Es≦io
o% However, E: Percentage of longitudinal elongation of paper (JIS P-813
2) ED: 〃 Ec: Cellophane 〃 ES: Percentage of longitudinal elongation of metal thin film processed flexible sheet (JIS P-8132) EF: Percentage of longitudinal elongation of thermoplastic resin film (JIS P-8132) It is structured with this feature in mind.

A metal thin film processed flexible sheet is a flexible sheet processed with a metal thin film processed layer. The flexible sheet is preferably thin, has high physical strength, and has excellent moisture and gas barrier properties, and has a thickness of 5 to 7 mm.
Any paper-like or film-like flexible sheet can be used.

This flexible sheet preferably has a thickness of 8 to 40 mm in order to reduce the thickness of the packaging material, reduce costs, and ensure physical strength. Various types of paper, synthetic paper, cellophane, -shaft (1
74. Molecular orientation (which may be horizontal or oblique) (including -axis stretching. In addition, -axis molecular orientation means that the tear strength in the direction parallel to the molecular orientation axis is at least twice the tear strength in the direction perpendicular to the molecular orientation axis. ) film,
Biaxial (including molecular orientation stretching) films, etc., especially,
A uniaxially or biaxially oriented film containing polyester resin, polyamide resin, polypropylene resin, or high density polyethylene (HDPE) resin as a main component is preferred.

The above-mentioned -axis molecularly oriented film is a film in which molecules are uniaxially oriented, and a typical uniaxially oriented film is a -axis stretched thermoplastic resin film. In particular, a uniaxially stretched thermoplastic resin film with a stretching ratio of 3 times or more is preferred. In addition, a single-layer or multi-layer blown-axial molecularly oriented film using a special resin composition, which is an unstretched film that is not subjected to stretching treatment, can be used as an inexpensive uniaxially molecularly oriented thermoplastic resin film.

The two-wheel stretched thermoplastic resin film may be stretched both vertically and horizontally, or may be stretched simultaneously in both directions. This biaxially stretched thermoplastic resin film is a film that has been stretched by 1.5 times or more in both length and width.

A metal thin film processing method for applying a metal thin film processing layer to a flexible sheet uses a known thin film forming method such as a vacuum evaporation method, a sputtering method, an ion blating method, an electron beam evaporation method, etc., and the metal thin film processing layer is provided on both or one side of the flexible sheet.

The metal thin film processing layer includes Af, Sn, Zn, Co, Cr, and N.
All metals such as aluminum, Fe, and Cu, alloys, and other metals capable of forming thin films can be used, but aluminum (AI) is most suitable in terms of cost and ease of processing.

The metal thin film processed layer is 55~55% in terms of physical strength as a laminate, light shielding property, antistatic property and moisture proofing, cost, and quality.
A thickness of 1200 people is preferred. In other words, if the thickness is less than 55 mm, the thin metal film processed flexible sheet alone cannot reduce the charge generated in the layers on both sides of the metal thin film processed flexible sheet, and the flexible sheet on both sides of the metal thin film processed flexible sheet and the heat Unless the thickness of the plastic resin film light-shielding layer is increased, the moisture-proofing and light-shielding properties required as a packaging material for photographic light-sensitive materials cannot be ensured. In addition, if the thickness exceeds 1,200 layers, antistatic, moisture-proof, and light-shielding properties can be ensured, but problems arise due to cost and vacuum deposition methods such as deterioration of the flexible sheet due to heating and reduction in physical strength of the finished laminated film. Therefore, it is difficult to put it into practical use. In the case of aluminum vacuum-deposited film, 70
The thickness is preferably 80 to 800 thick for normal use, more preferably 100 to 600 thick.

In metal thin film processing, the following method can be used to improve adhesion strength and prevent peeling and cracking of the metal thin film processed layer of the metal thin film processed flexible sheet.

(1) The surface of the flexible sheet is activated by performing treatments such as corona discharge treatment, ultraviolet treatment, flame treatment, dichromic acid treatment, and oxidation treatment with a sulfuric acid mixture.

(2) Polyester resin or polyamide resin with good metal affinity and excellent metal receptivity, polyurethane resin, epoxy resin, cellulose derivative, vinyl acetate resin, polyvinyl butyral resin, EAA, EE on the above-mentioned treated surface.
A. Apply a resin solution such as EMA resin.

(3) Previous item (2) such as epoxy resin before metal thin film processing
A protective layer such as polyvinyl butyral resin is applied as a top coat after processing the metal thin film.

(4) Before or after metal thin film processing, heat treatment is performed for a short time at a temperature around the melting point of the flexible sheet.

(5) A substance having good affinity with metals is added to the flexible sheet forming the metal thin film processing layer.

The obtained flexible sheet processed with a metal thin film has a protective layer containing butyral resin, acrylic resin, cellulose resin such as cellulose acetate, urethane resin, epoxy resin, polyester resin, ionomer resin, ethylene-ethyl acrylate copolymer. Appropriate resins such as (EEA) resin, various polyethylene resins, and polypropylene resins can be used. Further, wax, gelatin, polyvinyl alcohol, etc. can also be used.

The protective layer of the metal thin film processing layer is preferably formed to have an extremely thin thickness. Even when provided by extrusion lamination, static electricity will not be removed satisfactorily unless it is 50- or less.

When the thickness is reduced to 5g1 or less by a known solution coating method or spray coating method, the metal thin film processed layer can be protected and the effect of removing static electricity is also great.

The paper laminated on one side of the metal thin film processed flexible sheet can be unbleached kraft paper, neutral paper, metal mount, dust-free paper,
Synthetic paper, bleached kraft paper, Talvac Gi, Duostress paper, surface coated paper, etc. are available, and stretched films include polycarbonate resin, polyester H14M, polystyrene resin, EVAL resin, polyamide resin, polypropylene resin, HDPE resin, polyvinyl chloride. There are uniaxially or biaxially stretched films of resins and the like, and examples of cellophane include brain cellophane and vinylidene chloride coated cellophane.

When these paper, stretched film, or cellophane are used as the outermost layer, the temperature is 5°C or higher than that of the thermoplastic resin film.
In particular, it is preferable that the melting point is higher than 10°C, and not only does it have a silver-colored appearance with high commercial value, but it also absorbs little sunlight even when left in sunlight and prevents temperature rise. It is preferable that the material be white or transparent because it can prevent deterioration of the quality of the material.

In addition, in the case of stretched film, dust-free paper, or cellophane,
Has low dust generation.

The thermoplastic resin film having a longitudinal elongation percentage higher than the thin metal film processed flexible sheet laminated on the other side of the metal thin film processed flexible sheet used in the present invention is:
Various thermoplastic resins are used, but various polyolefin resins, especially polyolefin resin films containing 10% by weight or more of various ethylene copolymer resins and/or modified polyethylene resins, are preferred because they are inexpensive and can be heat-sealed reliably. , hot tack property, impurity sealing property, heat sealing strength, heat sealing suitability such as a wide allowable heat sealing width, and maintaining heat sealing strength over time.

The ethylene copolymer resin and/or modified polyethylene resin include the following.

(1) Ethylene copolymer resin ethylene-vinyl acetate copolymer resin, ethylene propylene copolymer resin, ethylene-1-butene copolymer resin,
Ethylene-butadiene copolymer resin, ethylene-vinyl chloride copolymer resin, ethylene-methyl methacrylate copolymer resin, ethylene-methyl acrylate copolymer resin,
Ethylene-ethyl acrylate copolymer resin, ethylene-
Acrylonitrile copolymer resin, ethylene-acrylic acid copolymer resin, ionomer resin (resin in which a copolymer of ethylene and unsaturated acid is crosslinked with metal such as zinc), ethylene-α-olefin copolymer resin (linear (2) Chlorinated polyethylene resin (3) Ethylene-vinyl acetate-vinyl chloride graft copolymer resin (4) Cross-linked polyethylene resin ( (by methods such as electron beam irradiation crosslinking, chemical crosslinking, etc.) (5) Polyethylene blend resins containing polyethylene as the main component and resins such as polyvinyl chloride, rubbers such as chloroprene rubber, elastomers, etc. (6) Other modified polyolefins Resins, i.e., ethylenically unsaturated dibasic acids or derivatives thereof, such as polyethylene resins, polypropylene resins, polybutene-1 resins, propylene-ethylene copolymers ( (including both random or block copolymers), ethylene/propylene/butene-1 terpolymer resin, propylene/butene-1 copolymer resin, ethylene/4-methylpentene-1 copolymer resin, etc. be.

The most preferred is L-LD, which is inexpensive and whose physical strength, heat-sealing suitability, ability to maintain heat-sealing strength over time, etc. do not deteriorate even when a light-shielding substance is added, and depending on the characteristics, they may actually improve.
This is a polyolefin resin film containing 10% or more of PE resin.

L-LDPE resin is called the third polyethylene resin, and is a low-cost, high-strength resin that has the advantages of both medium-low pressure and high-pressure polyethylene resins.

This resin is produced by low-pressure method or high-pressure improvement method, with ethylene and 3 carbon atoms.
It is a copolymer made by copolymerizing ~13 α-olefins, preferably 4-10 α-olefins, and is a low-medium density polyethylene resin having a linear structure with short branches. As the α-olefin, 1-butene, 1-octene, 1-hexene-1,4-methylpentene, 1-heptene, etc. are used. The density is generally considered to be that of low-medium density polyethylene resin, but commercially available products have a density of 0.87 to 0.95 g/c.
It is within the range of Ti.

Among these L-LDPE resins, those with a melt index (hereinafter referred to as M+) of 0.8 to 30 g/10 minutes (JIS
K-6760), density 0.870-0.940g/
c4 (JISK-6760), and α-olefins having 6 to 8 carbon atoms were obtained by a liquid phase process and a gas phase process.

To give a particularly preferred representative example by product name, Mitsui Petrochemical ■'s Ultozex, which is obtained by a liquid phase method and has 4-methylpentene-1, which has 6 carbon atoms, introduced into polyethylene as an α-olefin side chain. There are also MORETEC from Idemitsu Petrochemicals, Stamilex from DSM, and Dowlex from Dow Chemical, which introduce octene-1 having eight carbon atoms as an α-olefin side chain.

Examples of products obtained by the low-pressure gas phase method include TUFTHENE manufactured by Nippon Unicar ■ and TUFLIN manufactured by UCC Corporation, in which hexene-1 having 6 carbon atoms is introduced as an α-olefin side chain.

In addition, as recently released ultra-low density linear low density polyethylene resins, for example, NUC-FLX manufactured by UCC and F-Selen VL manufactured by Sumitomo Chemical Co., Ltd.
(Using butene-1 whose olefin has 4 carbon atoms).

When the above-mentioned thermoplastic resin film is used as the inner layer of a packaging material, the packaging material has excellent heat-sealing properties and improves bag-making suitability.

In addition, by using this thermoplastic resin film,
It improves pinhole resistance, tear strength, bursting strength, impact puncture strength, Gelbo test strength, moisture proofing, waterproofing, etc., and also provides low dust generation.

If the thermoplastic resin film contains light-blocking substances,
Improved light blocking properties, antioxidant properties, deodorizing properties, antistatic properties, etc.
When the thermoplastic resin film contains L-LDPE resin, physical strength and heat sealing properties (hot tack properties, contaminant sealing properties, heat sealing strength, heat sealing tolerance range, heat sealing strength over time, etc.) are improved.

This thermoplastic resin film can be laminated by extrusion lamination, or by laminating a separately formed film by blown film molding, T-die film molding, casting, etc. onto a metal thin film processed flexible sheet via an adhesive layer. It's okay.

The longitudinal elongation percentage (CJIS P-8132) of the metal thin film processed flexible sheet, paper, stretched film, cellophane, and thermoplastic resin film is E, 8E.

If Eo,,Eo,,EF, (E,,EoSEo)≦E8≦E, and 885100
%.

(E, , E, , Eo) ≦ Due to the bow relationship, the metal thin film processed flexible sheet is less likely to be stretched, making it difficult for the metal thin film processed layer to crack or peel off, providing moisture resistance, gas barrier properties, light shielding properties, and antistatic properties. It has excellent properties, appearance, etc.

Note that the vertical direction refers to the longitudinal direction during film molding.

To laminate paper, stretched film, or cellophane and thermoplastic resin film to metal thin film processed flexible sheet,
Various known methods may be used, such as adhesive method (
Wet lamination method, dry lamination method, hot melt lamination method, extrusion lamination method, coextrusion lamination method, etc. are used.

Typical adhesives include various polyethylene resins,
Polyolefin thermoplastic resin hot melt adhesives such as various polypropylene resins, ethylene-α olefin copolymer resin, ethylene-propylene copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer Examples include thermoplastic resins such as ethylene copolymer resins, ethylene-acrylic acid copolymer resins, polyethylene adhesive resins, ionomer resins, hot melt adhesives, and geothermally meltable rubber adhesives.

Typical examples of emulsion adhesives include polyvinyl acetate resin, vinyl acetate-ethylene copolymer, vinyl acetate and acrylic ester copolymer, vinyl acetate and maleate ester copolymer, acrylic copolymer, There are emulsions such as ethylene-acrylic acid copolymers.

Typical examples of latex adhesives include natural rubber, styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), and chloroprene rubber (CR).
There are rubber latex such as

In addition, adhesives for dry lamination include isocyanate adhesives, urethane adhesives, polyester adhesives, etc. In addition, paraffin wax, microcrystalline wax, ethylene-hinyl acetate copolymer resin I
Known adhesives such as hot melt laminating adhesives blended with JM, ethylene-ethyl acrylate copolymer resins, pressure-sensitive adhesives, heat-sensitive adhesives, etc. can also be used.

More specifically, polyolefin resin adhesives for extrusion lamination include various polyethylene resins,
Polymers made of polyolefin resins such as polypropylene resin and polybutylene resin, and ethylene copolymers (EV
In addition to resins such as A, EEA, etc., such as L-LDPE resin,
Ionomer resins (ionic copolymers) such as Dupon Co.'s Surlyn and Mitsui Polychemical's Himilan, Mitsui Petrochemical's Atmer, Examples include MODIC (adhesive polymer) manufactured by Mitsubishi Yuka. Other types of adhesives, such as UV-curable adhesives, have recently begun to be used. In particular, when adhesiveness is required, it is preferable to use a polyolefin resin adhesive layer modified with an unsaturated carboxylic acid or a derivative thereof.

In particular, LDPE resin and L-LDPE resin are preferred because they are inexpensive and have excellent lamination suitability. In addition, the above-mentioned resin is
Particularly preferred is a mixed resin in which more than one type of resin is blended to cover the drawbacks of each resin.

The thickness of the adhesive layer formed by extrusion lamination using a thermoplastic resin is usually 6 to 50-1, preferably 10 to 20! ! m, but it is determined based on cost, adhesive strength, lamination speed, total thickness of the laminate, etc., and is not particularly limited to this value.

For adhesion on the metal thin film layer side, it is preferable to use an adhesive for dry lamination in order to improve ease of opening and prevent cracking and peeling of the metal thin film layer.

The coating amount of the adhesive layer at this time is usually 20 g/rd or less, preferably 1 to 10 g/rd.

To improve the adhesive strength of the adhesive layer, an adhesion promoter or crosslinking agent called an AC agent (anchor coating agent) in the laminate industry is used. This AC agent is different from a simple adhesive; it is called a Primer or Adhesine in the sense that it bonds chemically.
Also called dromo ter. Representative examples of AC agents are described below.

(1) Organic titanate (titanium-based) anchor coating agent,
(2) Polyethyleneimine (imine type) anchor coating agent, (3) Isocyanate type anchor coating agent, (4)
Polyester-based and urethane-based anchor coating agent, (5
) polyolefin anchor coating agent, (6) polybutadiene anchor sheet agent, etc.

The AC layer is preferably formed with an extremely thin thickness. The coating method for AC agent is gravure roll coating method,
Kiss roll coating method, drop coating method, bar coating method, reverse roll coach ink method, direct roll coating method, air knife coating method, etc. are used.

Further, in order to improve the adhesive strength of the extrusion lamination adhesive layer, the following surface physical treatment method is performed. Two or more of these may be used in combination, or may be combined with AC treatment.

(1) flame treatment, (2) plasma treatment method,
(3) Corona discharge treatment, (4) sandblasting treatment, (
5) Chemical treatment, (6) Ozone treatment, (7) Breheat treatment, (8) Ultraviolet irradiation treatment, (9) High frequency heating treatment, On) Electric induction heating treatment, 01) Microwave treatment, etc. Also, metal thin film processing Layers other than the flexible sheet may also have light blocking properties. For this purpose, one or more of the flexible sheets, adhesive layers, or other layers may contain 0.1 to 30% by weight of a light-blocking substance, or colored paper, aluminum foil, galvanized thin steel sheets, etc. Thickness 5I! More than 50 m! ! Metal foil of less than m or 55 to 1
Light-shielding layers such as metal thin film processed layers such as metal vapor-deposited layers (e.g. aluminum vapor-deposited paper) or films (e.g. aluminum vapor-deposited films) are laminated or printed. Use methods such as adding .

When only a light-shielding substance is contained to ensure light-shielding properties, the appropriate amount is 0.5 to 36 g per unit area (e) of the laminated film. It is generally undesirable to add 12% by weight or more of a light-shielding substance to a stretched film because it causes fish eyes and reduces physical strength.
A range of 7% by weight is preferable.

When added to flexible sheets such as unstretched films and paper, this is not the case; the amount can be up to 30% by weight, and up to 36g per unit area (e).

Light-blocking substances refer to all substances that do not transmit visible and ultraviolet rays, but representative examples include various carbon blacks, graphite, titanium nitride, titanium oxynitride, aluminum powder, iron oxide, zinc white, Bengara, Aluminum paste, various colored pigments, metal fibers, various colored dyes, cadmium pigments, yellow lead and titanium oxide, barium sulfate,
Examples include white pigments such as calcium carbonate, mica, talc, and clay, various metal powders, and various metal fibers. In terms of quality, cost, and light-shielding ability, materials with lower volatile substances removed than various carbon blacks, aluminum powders, and aluminum pastes are better for packaging photographic materials.

Carbon black, which is a typical light-shielding substance used in the present invention, includes gas black, furnace black, anthracene black, acetylene black, channel black, oil smoke, powder smoke, animal black, vegetable black, and the like.

When used as the packaging material of the present invention, there is no generation of capri, there is little increase or decrease in photosensitivity, and the light shielding ability is large.
Among carbon blacks, 9115-9 and average particle size 10 are particularly effective because they are less likely to cause carbon black clumps or pinholes in the film, such as fins, even when added to L-LDPE resin films. ~10
0 mμ is preferable in terms of improved light-shielding properties and less deterioration of film physical properties, and the most preferable ones are pH 6 to 9,
It is a furnace carbon black with an average particle size of 15 to 50.

To make the light shielding property as good as possible by adding the same amount,
When packaged as a packaging material, a light-blocking substance is added to the side that comes into contact with the product (the so-called inside side).

As the blending method, the masterbatch method and the die color granulation method are preferred from the viewpoint of cost, prevention of workplace contamination, and the like.

Furthermore, in the present invention, various additives may be added to each layer as necessary.

Representative examples of additives are described below, but the present invention is not limited thereto, and any known additives can be selected.

(Additive types) (Representative examples) (1) Plasticizers; Phthalate esters, glycol esters, fatty acid esters, phosphate esters, etc.; Lead-based, cadmium-based, zinc-based, alkaline earth metal-based, organic tin-based, etc. (3) Antistatic agent; cationic surfactant, anionic surfactant, nonionic surfactant (2) Stabilizer surfactant, bifacial active agent, various carbon blacks, metal powder, graphite, etc.; phosphate ester , halogenated phosphate esters, halides, inorganic substances, phosphorus-containing polyols, etc.; alumina, kaolin, clay calcium carbonate, mica, talc, titanium oxide, silica, etc.; glass roving, metal fiber, glass fiber, glass milled fiber, carbon fiber, etc. ; Inorganic pigment (Al+ FezO3, T10z.

ZnO, CdS, carbon black, etc.), organic pigments (
Inorganic blowing agents (ammonia carbonate, sodium bicarbonate), organic blowing agents such as Toroso type, Ab type), etc. (9) Vulcanizing agents; Vulcanization accelerators, accelerators, etc. (10) Deterioration inhibitors; Ultraviolet absorbers, antioxidants, gold (6) reinforcing agents (5) fillers (4) flame retardants (7) colorants (8) blowing agents, deactivators, peroxide decomposers, etc. (11) lubricants Paraffin, wax, fatty acid type, fatty acid amide type, silicone type, ester type, higher alcohol, etc. (12) Coupling agent; Silane type, titanate type, chromium type, aluminum type, etc. (13) Various thermoplastic resins , rubber, etc. (14) Water-absorbing resin, dehumidifier, desiccant, etc. (15) Deodorizer (16) Oxygen absorber (oxygen scavenger) (F) Air freshener The packaging material of the present invention includes black and white and color halogenated Silver photographic materials, diazo photographic materials, photosensitive resins, self-developing photographic materials, autopositive photographic materials, heat-sensitive materials, diffusion transfer photographic materials, reversal photographic materials, etc. Ideal for packaging bags for photographic materials whose quality deteriorates due to light, gas, moisture, or friction.

In addition, it is also suitable for packaging bags for various photosensitive materials, such as foodstuffs, pharmaceuticals, chemicals, feed, etc.

The packaging material of the present invention can be made into packaging bags of various shapes, such as - vertical bags, - heavy gusset bags, - heavy self-supporting bags, etc., and it is preferable to provide an opening notch at one or more places for easy opening.

In addition to known plastic film sealing methods such as heat sealing, impulse sealing, fusing sealing, ultrasonic sealing, and high-frequency sealing, bag making can also be done using appropriate adhesives, pressure-sensitive adhesives, etc. It is.

[Effect]

In the present invention, the vertical elongation percentage (JIS P-8
123) (E, , E9, Eo) ≦ ES ≦ town, and the metal thin film processed flexible sheet is used as the intermediate layer, so light shielding properties, moisture proofing properties, gas barrier properties, and antistatic properties are provided, and the metal thin film processed layer Since damage to the material is prevented, the above characteristics can be maintained.

In addition, since a flexible sheet with a lower elongation than a metal thin film processed flexible sheet is laminated on one side,
Provides easy opening and does not cause curling. Furthermore, even if tension is applied to the packaging material, the metal thin film processed flexible sheet is prevented from elongating, thereby preventing cracking, peeling, and reduction in adhesive strength of the metal thin film processed layer.

In addition, a thermoplastic resin film with a higher elongation than the thin metal film processed flexible sheet is laminated on the other side, improving physical strength, moisture proofing, and waterproofing, as well as providing heat sealability and low dust generation. It will be done.

In addition, since both sides are made of a flexible sheet that does not cause curling and a thermoplastic resin film, suitability for bag making is improved.

〔Example〕

Examples of the packaging material of the present invention will be described based on FIGS. 1 to 6.

The packaging material shown in Fig. 1 is a metal thin film processed flexible sheet 3 obtained by processing a metal thin film processed layer 2 on a flexible sheet l.
Paper, stretched film or cellophane 4 is laminated on the flexible sheet 1 side via an adhesive layer 5, and a thermoplastic resin film 6a is laminated on the other metal thin film processed layer 2 side via an adhesive layer 5. ing.

The packaging material shown in FIG. 2 is different from the packaging material shown in FIG. Plastic resin films 6a are laminated.

The packaging material shown in FIG. 3 is the same as the packaging material shown in FIG. 1, but instead of the thermoplastic resin film 6a, a two-layer coextruded film 7a consisting of two thermoplastic resin films 6a, 6a is laminated.

The packaging material of FIG. 4 is different from the packaging material of FIG. 1 in that a two-layer coextruded film 9a consisting of a thermoplastic resin film 6a and a blocking film 8 is used instead of the thermoplastic resin film 6a. Blocking laminated film 10 laminated so that comrades adhere to each other
a are stacked.

In the packaging material shown in FIG. 5, instead of being laminated via the adhesive layer 5 in the packaging material shown in FIG. has been done.

In the packaging material of FIG. 6, a thermoplastic resin film 6a is directly laminated on the flexible sheet 1 in the form of an extrusion laminate film, instead of being laminated via the adhesive layer 5 in the packaging material of FIG. There is.

FIG. 7 is a partial cross-sectional view showing the layer structure of a comparative example. In this packaging material, a thermoplastic resin film 6a is laminated on the metal thin film processed layer 2 side of the metal thin film processed flexible sheet 3, and a light-shielding LDPE resin film lla is laminated on the flexible sheet 2 side.

Next, the results of an experiment comparing the characteristics of the invention products (1), (2), (2) and the comparative product (2) will be explained.

Invention product■ The layer structure corresponds to that shown in FIG.

The metal thin film processed flexible sheet 3 uses a biaxially stretched polyester resin film as the flexible sheet 1, uses an aluminum vacuum vapor deposited layer with a thickness of 400 mm as the metal thin film processed layer 2, and has a longitudinal elongation percentage (JIS P-8
123) was 73% and the thickness was 12-.

Cellophane 4 has a longitudinal elongation percentage (JIS P-8123
A vinylidene chloride-coated cellophane with a thickness of 25p and a thickness of 52% was used.

The thermoplastic resin film 6a has an average particle diameter of 21 mμ, p
MI containing 3% by weight of Hs, o carbon black (furnace carbon black #44B, manufactured by Mitsubishi Kasei)
Consisting of ethylene/4-methylpentene-I copolymer resin with a density of 2.1 g/10 min and a density of 0.920 g/cffl,
Vertical elongation percentage (JIS P-8123) is 1187
% and a thickness of 50 m was used.

Adhesive layer 5 is M 12.4g/10min, density 0.919
15-thick LD using LDPE resin of g/c 111
A PE resin extrusion laminate adhesive layer was used.

Invention product■ The layer structure corresponds to that shown in FIG.

The metal thin film processed flexible sheet 3 uses a two-wheel stretched nylon resin film as the flexible sheets 1 and 1,
As the metal thin film processing layer 2a, an aluminum vacuum-deposited layer with a thickness of 400 mm was used, and the vertical elongation percentage (JIS P-
8123) was 52% and the thickness was set to ts and m.

The stretched film 4 has a vertical elongation percentage (JIS P81
A biaxially stretched polystyrene resin film having a thickness of 20 m and containing 27% of 23) was used.

The thermoplastic resin film 6a contains 3% by weight of carbon black (described above), 76.95% by weight of ethylene/4-methylpentene 1 copolymer resin (described above), and M I 1.1. g/1
0 min, HDPE resin with density 0.954 g/cri, 20
% by weight, 0.05% by weight of oleic acid amide, a longitudinal elongation percentage (JIS P-8123) of 852%, and a thickness of 50p.

The adhesive layer 4 used had the same thickness of 15 mm as that of the product I of the present invention.

Invention product■ The layer structure corresponds to that shown in FIG.

As the metal thin film processed flexible sheet 3a, an aluminum vacuum vaporized = V-axis stretched nylon resin film having a thickness of 15 mm, which is the same as that of the product (1) of the present invention, was used.

As paper 4, bleached kraft paper with a longitudinal elongation percentage (JIS P-8123) of 2% and a thickness of 52 mm and 2% by weight of acrylamide was used.

The thermoplastic resin film 6a is made of an ethylene-octene-1 copolymer resin containing 3% by weight of carbon black (mentioned above), an M I of 2.0 g/10 min, and a density of 0.920 g/aJ. (JIS P-8123
) was used as an L-LDPE resin blown film with a thickness of 50% and a thickness of 1027%.

The adhesive layer 4 used had a thickness of 15 mm, which is the same as that of the product (2) of the present invention.

Comparison product ■ The layer structure corresponds to that shown in FIG.

As the metal thin film processed flexible sheet 3a, an aluminum vacuum-deposited biaxially stretched resin film having a thickness of 15I1 m, which is the same as that of the product (2) of the present invention, was used.

6a has the same thickness as the product I of the present invention, 50I! A thermoplastic resin film containing a light-shielding substance of m was used.

The light-shielding LDPE resin film Ila has a longitudinal elongation percentage (JIS
Light-shielding LDP with P8123) of 416% and thickness of 50-
E resin film was used.

The experimental results are shown in Table 1.

The above examples are representative examples of preferred embodiments of the laminated sheet of the present invention suitable for easy-to-open packaging bags for photosensitive materials, and the present invention is not limited thereto. Various layer configuration combinations are possible that satisfy the content of the range.

Table 1 The evaluation is based on the following.

◎...Excellent ○...Excellent...Acceptable (within practical limits) Mu...Problems (improvement required) ×...Not practical *Easy to open with A-notch Each laminated layer Make a three-sided human-sealed bag using film, and
Judging from the ease of tearing when a notch is placed in the heat-sealed part and the tear is made with a fingertip, as well as the condition of the cut. *B: Appearance of the packaging bag, occurrence of wrinkles and streaks, melting state of the heat-sealed part,
Judging from a comprehensive evaluation of appearance etc. *C Heat seal suitability Hot tack property, contaminant sealing property, heat seal strength,
Judging from comprehensive evaluation of pinhole resistance, allowable heat sealing width, heat sealing strength over time, etc. *Judging from the curling state that occurs when a laminated film with a D-curving width of 80 cm and a length of 1 m is dropped vertically (processing machine suitability) *Determined based on E-bag-making suitability When sheet-like photosensitive materials are packaged using each laminated film into 3-sided sealed bags using an automatic bag-making machine, pinholes are unlikely to occur, heat-seal suitability, and manufacturing Judging from a comprehensive evaluation of ease of bagging, etc. [Effects of the invention] Despite its high physical strength, the packaging material of the present invention has excellent ease of opening, less curling, and good heat resistance and heat sealability. Therefore, it has good suitability for bag making and packaging, and has a good appearance. In particular, even if tension is applied during the lamination process, processing process, and transportation process, the thin metal film processed layer of the metal thin film processed flexible sheet is protected by the flexible sheet with low elongation, and cracks, peeling, wrinkles, and curling do not occur. As a result, excellent moisture-proofing properties, gas barrier properties, antistatic properties, and light-shielding properties can be maintained.

[Brief explanation of the drawing]

1 to 6 are partial cross-sectional views showing the layer structure of an embodiment of the packaging material according to the present invention. FIG. 7 is a partial sectional view showing the layer structure of a comparative example, and FIG. 8 is a partial sectional view showing the layer structure of a conventional example. 1. Ia...Flexible sheet 2...Metal thin film processed layer 3.3a...Metal thin film processed flexible sheet layer 4.
4a...Paper, stretched film or cellophane 5.5a...
- Adhesive layer 6, 6a... Thermoplastic resin film a... Indicates that it contains a light-shielding substance.

Claims (3)

[Claims] (1) A laminated sheet in which a metal thin film processed flexible sheet is laminated with paper on one side and a thermoplastic resin film on the other side with an adhesive layer, and the vertical elongation percentage of the constituent material is E_S. , E_P, and E_F are E_P≦E_S≦E_F and E_S≦100%, provided that E
_P: Paper longitudinal elongation percentage (JISP-8132) E
_S: Percentage of longitudinal elongation of metal thin film processed flexible sheet (JISP-8132) E_F: Percentage of longitudinal elongation of thermoplastic resin film (J
ISP-8132) Packaging material characterized by: (2) A laminated sheet in which a stretched film is laminated on one side of a metal thin film-processed flexible sheet and a thermoplastic resin film is laminated on the other side with an adhesive layer, and the longitudinal elongation percentage of the constituent material is E_S, E_D, E_
F) relationship is E_D≦E_S≦E_F and E_S≦100%, but E
_D: Percentage of longitudinal elongation of stretched film (JISP-8
132) E_S: Percentage of longitudinal elongation of metal thin film processed flexible sheet (JISP-8132) E_F: Percentage of longitudinal elongation of thermoplastic resin film (J
ISP-8132) A packaging material characterized by: (3) A laminated sheet in which cellophane is laminated on one side of a metal thin film processed flexible sheet and a thermoplastic resin film is laminated on the other side with an adhesive layer, and the longitudinal elongation percentage of the constituent material is E_S. , E_C, and E_F are E_C≦E_S≦E_F and E≦100%, provided that E_C
: Percentage of longitudinal elongation of cellophane (JISP-8132) E_S: Percentage of longitudinal elongation of metal thin film processed flexible sheet (JISP-8132) E_F: Percentage of longitudinal elongation of thermoplastic resin film (J
ISP-1832).