JPH0453412B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a packaging material suitable for photographic materials. [Prior Art] Various types of packaging materials for photographic materials have been widely put into practical use, and various performances are required depending on the intended use. Packaging materials that completely block light are used as packaging materials for photographic materials that lose their quality value when exposed to light. In this case, the required properties include packaging material slit suitability, gas barrier properties, light shielding properties, moisture proofing properties, rigidity, physical strength (breaking strength, tear strength, impact puncturing strength, gelbo test strength, abrasion strength, etc.), and heat seal suitability ( heat seal strength,
Cut sealing properties, hot tack properties, contaminant sealing properties, etc.), antistatic properties, flatness, sliding properties, etc. It is extremely difficult to have all of these properties in a single film material, and conventionally, as shown in Figure 14, very thick high-pressure branched film materials kneaded with carbon black, pigments, etc. have been used. Density polyethylene (hereinafter referred to as LDPE) Resin light shielding film layer 21 single layer film or LDPE
Composite laminate films of resin films and flexible sheet layers such as paper, aluminum foil, and cellophane have been used. An example of a composite laminate film is shown in Figure 15, which is used in products that particularly require moisture resistance.
A metal foil layer 6 is laminated on an LDPE resin light shielding film layer 21 with an adhesive layer 4 interposed therebetween, and a flexible sheet layer 5 is further laminated with an adhesive layer 4 interposed therebetween. Figure 16 shows a packaging material that requires physical strength and is conventionally used for the inner paper of double gusset bags for color photographic paper, and the flexible sheet layer 5 shown in Figure 15.
Adhesive layer 4 on the outside and LDPE resin light shielding film layer 2
It is a laminated film with a seven-layer structure in which 1 is laminated. The present inventor has conducted extensive research to improve packaging materials for photographic materials, and has developed a material with improved physical strength by combining two layers of uniaxially stretched film (Japanese Patent Laid-Open No. 57-6754). It has already been disclosed. In addition, packaging materials using low-pressure processed linear low-density polyethylene (hereinafter referred to as L-LDPE) resin are composed of polyethylene polymer and 1% or more of a light-shielding substance, and are made of a total ethylene polymer.
A film having at least one light-shielding film containing 50% by weight or more of L-LDPE resin has already been disclosed (Japanese Patent Application Laid-open No. 132555/1983). In addition, on both sides of the metal vapor deposited film layer, L of 50% or more by weight is added.
-We have also developed a packaging material in which polyethylene polymer layers containing LDPE resin and at least one layer containing a light-shielding substance are laminated, and the strength and thickness difference of the polyethylene polymer layers have a specific relationship (Patent application No. 59 −178047). Furthermore, among L-LDPE resins, ethylene and heptene-1 or octene-1 are copolymerized by a liquid phase method, with a density of 0.870 to 0.925 g/cm ³ and a melt index of 1.2 to 10 g/10 min. We discovered that this resin has particularly excellent physical strength, heat sealability, etc., and has a small difference in tear strength in the vertical and horizontal directions, making it suitable for packaging materials.
A light-shielding packaging material for photosensitive materials having a polyethylene polymer film layer formed from a polyethylene polymer film having a (longitudinal tear strength)/(horizontal tear strength) ratio of 0.6 or more, which is formed from an inflation film with a thickness of 20 μm or more, including weight%. was also developed (Special Application No. 60-012663). In addition, at least 40% by weight of linear low-pressure low-density polyethylene resin, 0.1% to 15% by weight of carbon black, and 0.03% to 15% by weight of carbon black.
We discovered that a linear low-pressure low-density polyethylene film containing 1% by weight of a fatty acid amide lubricant has good sliding properties and does not cause blocking, and developed a packaging material for photographic materials that uses this film as the innermost layer ( (Special Application No. 1983-029416). [Problems to be solved by the invention] Conventional composite laminate films have been constructed to improve the above-mentioned physical properties, but the physical properties are still not sufficient for products other than those using L-LDPE films. However, there were drawbacks such as tearing or puncturing during packaging, and peeling of the heat-sealed part. Furthermore, adding a large amount of light-blocking substances such as carbon black will significantly deteriorate the physical strength, so the amount added should be around 3%, and the thickness of the film laminated with other flexible sheet layers should be at least 70μ. It was hot. As a result, the packaging becomes bulky and the rigidity of the laminated film increases, resulting in poor packaging workability and high costs. For example, in the laminated film shown in FIG. 15, the metal foil 6 provides gas barrier properties, improves moisture resistance,
It is used to prevent static electricity, but as a result, tear strength, impact puncture strength, Gelbo test strength, etc. deteriorate significantly, which can lead to breakage problems, especially when packaging heavy items. Ta. For this reason, the thickness of carbon black-containing polyethylene film has been increased to 70 μm or more, but it still does not have sufficient physical strength, and for example, a 7-layer laminated film as shown in Figure 16 is used to package color photographic paper. It has been. In addition, in the case of the packaging material described in JP-A-57-6754, the physical strength such as tear strength is improved to some extent, but as the adhesive layer becomes thicker and the adhesive strength increases, the tear strength not only decreases but also increases. Because it uses a uniaxially stretched high-density polyethylene film layer, it has poor heat-sealing properties and sometimes causes problems during processing and packaging. In addition, when using a cross-laminated film in which uniaxially stretched film layers are directly laminated crosswise without using aluminum foil, pinholes occur in the gusset part of the gusset bag when the product is packaged in the gusset bag, making it difficult to use as a packaging material for photographic light-sensitive materials. There were problems due to poor light shielding, moisture proofing, and gas barrier properties. By using linear low-density polyethylene (hereinafter referred to as L-LDPE) resin in packaging materials, it is possible to increase the physical strength such as tear strength and Gelbo test strength, as well as increase the amount of light-shielding substances such as carbon black mixed in. We were able to improve the above-mentioned problems. However, L-LDPE resin, which is a copolymer of ethylene and α-olefin having 6 or more carbon atoms, has a large physical strength of the film and good heat-sealability, making it the 10th
As shown in the figure, it is ideal for packaging where the product outlet is not completely heat-sealed but sealed with tape or glue. However, when the thickness of the film is increased, not only does the film formability deteriorate, but the appearance of the expensive molded film also deteriorates due to its surface condition. However, it is difficult to open the package when taking out the product.
In addition, not only the properties of the front and back sides of the film, especially the slipperiness, were greatly different, but also problems occurred in the film's suitability for packaging processing, such as the slitting and cut-sealing properties of the film. In addition, L-LDPE resin, which is a copolymerization of ethylene and α-olefin having 4 carbon atoms, is inexpensive, but tends to have vertical molecular orientation, has low tear strength in the vertical direction, and has problems with other physical properties. . Furthermore, films to which carbon black has been added have high water absorption properties, and in the case of a single light-shielding film layer, the moisture resistance deteriorates, so it is necessary to increase the thickness of the film or to laminate layers of aluminum foil or metallized film. In particular, for packaging materials for photographic materials that are processed and packaged under safelight (a safety light that does not expose photographic materials to light), it is preferable that the front and back sides can be distinguished under safelight, and the thickness of the film should not be increased. Even under sunlight, it is necessary to ensure light-shielding properties. It not only has excellent moisture proofing, heat resistance, light blocking properties, gas barrier properties, slipping properties, tear strength, impact puncturing strength, cut sealing properties, gelbo test strength, etc. required for packaging materials for photographic materials, but also has hot tack properties and natural aging properties. It has excellent suitability for moisture-proof packaging, such as excellent heat sealing strength over time at high temperatures.
It has been desired to develop an inexpensive packaging material that has excellent film formability, packaging material slitting suitability, printing suitability, ease of opening sealed bags, and processing and packaging workability under safelight. In particular, packaging materials for dental X-ray films, packaging materials for radiographic films (batch films) used to detect the radiation exposure of radiation workers, and
As a packaging material for vacuum-sealing X-ray film as described in Publication No. 24089, a thermoplastic resin film layer alone can satisfy all the characteristics required as a packaging material for photographic materials. There was a desire to develop inexpensive packaging materials. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide an inexpensive packaging material for photographic materials that has improved product insertability, film slitting suitability, physical strength, heat seal suitability, etc. [Means for Solving the Problems] In order to achieve the above object, the present invention has a melt index of 0.2 to 5.0 g/10 minutes and a density of 0.870 to 0.870.
The first linear low density polyethylene resin is 0.940 g/cm ³ and is made by copolymerizing ethylene with butene-1 having 4 carbon atoms, and has a melt index of 5 to 80% by weight and a melt index of 0.5 to 10 g/10 minutes. and the density is 0.870~0.940g/ ^cm3
and 4-methylpentene-1 or hexene-1 having 6 carbon atoms in ethylene or 8 carbon atoms
50% by weight or more of a linear low-density polyethylene resin having 20 to 95% by weight of a second linear low-density polyethylene resin copolymerized with octene-1;
This packaging material for photographic materials is characterized in that it comprises at least one linear low-density polyethylene resin light-shielding film layer containing 0.1 to 10% by weight of a light-shielding substance. The packaging material for photographic materials of the present invention is L-
It includes at least one LDPE-based resin light-shielding film layer. As long as it has at least one L-LDPE resin light-shielding film layer, it may be a single layer or may be laminated with other layers such as another flexible sheet layer or a thermoplastic resin layer.
Alternatively, two or more L-LDPE resin light-shielding film layers may be provided. This L-UDPE resin light-shielding film layer contains 50% by weight or more of L-LDPE-based resin and 0.1 to 10% by weight of a light-shielding substance. The L-LDPE resin light-shielding film layer contains 50% by weight or more of L-LDPE resin,
As long as the light-shielding substance is contained in an amount of 0.1 to 10% by weight, other substances such as other thermoplastic resins, lubricants, etc. may be contained. The L-LDPE resin, which is an essential component of the L-LDPE resin light-shielding film layer, contains 5 to 80% by weight of the L-LDPE resin.
It has a 1L-LDPE resin and 20-95% by weight of a 2nd L-LDPE resin, and may contain other substances as long as it has these. The 1st L-LDPE resin has a melt index of
It has a density of 0.870 to 0.940 g/cm ³ at a rate of 0.2 to 5 g/10 minutes, and is made by copolymerizing ethylene with butene-1 having 4 carbon atoms. A typical example of this 1L-LDPE resin is one produced by a low-pressure, gas-phase reaction in the presence of a highly active catalyst called the Unipol process developed by Union Carbide Company of the United States. This L-LDPE resin has a narrow molecular weight distribution and is linear compared to branched low-density polyethylene resin (hereinafter referred to as LDPE) produced by a conventional high-pressure process (3000 atm, 300°C). Since it is an energy-saving process product, it is inexpensive, has good hot-tack properties and impurity sealing properties, and has excellent cold resistance with little loss of heat-seal strength at low temperatures and over time, but it is prone to blocking and has poor physical strength. There are problems such as molecular orientation being easier in the vertical direction than the molecular structure, and tearing strength in the vertical direction being small. Manufacturing methods other than the gas phase method include a liquid phase method and a high pressure modification method using ionic polymerization. The specific product names and manufacturing methods are vapor phase method...G Resin (Unipol) (UCC),
NUC polyethylene-LL (Nippon Unicar), equal liquid phase method...Idemitsu polyethylene L (Idemitsu Petrochemical),
Examples include Nisseki Linirex (Nippon Petrochemical), Skrea (DuPont Canada), improved high-pressure method (ionic polymerization)...Rotrex (CDF chimie), etc. The second L-LDPE resin has a melt index of
Copolymerize ethylene with 4-methylpentene-1 or hexene-1 having 6 carbon atoms or octene-1 having 8 carbon atoms with a density of 0.870-0.940 g/cm ³ at 0.5-10 g/10 minutes. This is what I did. As a resin made by copolymerizing 4-methylpentene-1, which has 6 carbon atoms, and ethylene, there is Urtozex, manufactured by Mitsui Petrochemical's solution method, and as a resin made by copolymerizing hexene-1 and ethylene, there is Union. There is TUFLIN, a vapor phase method manufactured by Carbide. Examples of resins made by copolymerizing octene-1, which is an α-olefin having 8 carbon atoms, and ethylene include Stamilex produced by the liquid phase process manufactured by DSM-Stamicarbon Co., Ltd. and Dowlex produced by the liquid phase process produced by Dow Chemical Company. The same L-LDPE resin is made by copolymerizing butene-1 with 4 carbon atoms with ethylene as α-olefin, and 4-methylpentene-1 with 6 or more carbon atoms, hexene-1 as α-olefin.
1. L-, which is copolymerized with ethylene and octene-1
Although the price is more than 20% cheaper than LDPE resin, the tear strength is less than 1/2, so the two are completely different resins, and even when used as a blend, the mixing ratio
Unless the grade, etc. is within a limited range, the light-shielding film cannot be used as a packaging material for photographic materials. The light-shielding substance, which is an essential component of the L-LDPE resin light-shielding film layer, is a material that can be mixed and dispersed in the thermoplastic resin and does not transmit visible light, ultraviolet rays, etc. Examples of light shielding substances that can be used in the present invention include various carbon blacks, iron oxide, zinc white, titanium oxide, clay, aluminum powder, aluminum paste, calcium carbonate, mica, barium sulfate, talcum cadmium pigments, yellow lead, Bengara, Examples include organic pigments and inorganic pigments such as cobalt blue, copper phthalocyanine pigments, monoazo or polyazo pigments, and aniline black. Among these light-shielding substances, in terms of quality, cost, light-shielding ability, etc., it is better to use low-volatile substances than colored pigments that easily absorb or reflect light, especially various types of black pigments such as carbon black, and silver-colored pigments such as aluminum powder and aluminum paste. Preferably, it is removed. Methods for blending these light-shielding substances into the L-LDPE resin include the masterbatch coloring method and the compound coloring method, which have been commonly used in the past. The above-mentioned light-shielding substance may be used in the form of a powder coloring agent, a paste coloring agent, a slippery coloring agent, a masterbatch, a dye/pigment, or a colored pellet, depending on the resin used, the machine used, the cost, etc. Regarding the amount of the light-shielding substance added, for example, if carbon black, which is a typical light-shielding substance, is oriented, the light-shielding property will surely improve as the amount is added. However, with conventional thermoplastic resins, various physical strengths decrease, and when used in films for packaging photographic materials, the amount of carbon black must be kept to about 3% by weight. It was necessary to make the thickness 70 μm or more. This resulted in bulky packaging and increased rigidity of the laminated film, resulting in poor packaging workability and problems in terms of resource conservation. The present inventors used L-LDPE resin, which has hitherto had problems as a packaging film, in place of the conventional high-pressure branched low-density polyethylene resin, and tested the effect of carbon black compounding. As a result,
When carbon black is added to L-LDPE resin, high-pressure branched low-density polyethylene (hereinafter referred to as
The unexpected result was that the physical strength increased significantly, contrary to the case of resins (denoted as LDPE). LDPE resin films are inherently lower in strength than L-LDPE resin films, but the strength decreases particularly when carbon black is added.
On the other hand, the strength of the L-LDPE resin film is greatly improved by adding carbon black. The L-LDPE resin composition of the present invention is a copolymer resin of ethylene and butene-1 that does not have very high physical strength and is easy to orient molecules in the longitudinal direction.
Since it always contains LDPE resin in a blend, the amount of carbon black added is limited to a low level. The effect of carbon black blending begins to occur at 0.1% by weight, clearly becomes apparent at 1% by weight, and becomes noticeable when it exceeds 3% by weight, but as the blending amount increases further, bumps occur more and costs increase. To.
If it exceeds 15% by weight, the physical strength decreases and the occurrence of lumps increases due to poor dispersion of carbon black, which becomes a problem in terms of poor light-shielding properties due to pinholes. Moreover, the cost is also relatively high. Therefore, the amount of carbon black added is 0.1 to 10% by weight based on economical efficiency, light shielding properties, occurrence of lumps, tear strength, etc.
is preferred, and 3 to 7% by weight is particularly preferred. This tendency also holds true for other light-shielding substances. Examples of the classification of carbon black, which is a typical light shielding material used in the present invention, according to the manufacturing method include channel method carbon black, gas furnace method carbon black, thermal method carbon, etc.
Examples of classification based on raw materials are gas black, oil furnace black, anthracene black,
There are acetylene black, oil smoke, pine smoke, animal black, vegetable black, etc. In the packaging material of the present invention, furnace carbon black is preferable for the purpose of improving light-shielding properties, cost, and physical properties, and acetylene carbon black and ketsien carbon black are preferable as light-shielding substances that are expensive but have an antistatic effect. If necessary, it is also preferable to mix two or more types of light-shielding substances according to the required characteristics. On the other hand, among these carbon blacks, those having a pH of 5 to 9 and an average particle diameter of 10 to 120 m.mu. are preferred, and furnace carbon blacks having a pH of 6 to 9 and an average particle diameter of 15 to 30 m.mu. are particularly preferred. By using particles with such pH and particle size, there is less fogging, less increase and decrease in photosensitivity, greater light shielding ability, and even when added to L-LDPE film, no carbon black lumps are formed. It is possible to obtain a packaging material that has a number of advantages, such as being less likely to have pinholes caused by dents or fisheyes. As mentioned above, there are various ways of blending the light-shielding substance into the L-LDPE resin, but the master batch method is preferred from the viewpoint of cost, prevention of contamination of the workplace, etc. Japanese Patent Publication No. 40-26196 discloses a method for preparing a master batch of polymer carbon black by dispersing carbon black in a solution of a polymer dissolved in an organic solvent; A method for making a masterbatch by dispersing carbon black in polyethylene is shown. It is a light-reflective light-shielding material that is the second most preferred after carbon black as a light-shielding material added to the L-LDPE resin light-shielding film layer, giving it a silvery appearance with high commercial value, and has moisture-proofing, light-shielding, and antistatic properties, and is good under sunlight. We will explain metal powders that are excellent in many respects, such as heat insulation and gas barrier properties. As the metal powder, it is particularly preferable to use aluminum powder or a material obtained by removing lower volatile substances from aluminum paste and kneading it into a thermoplastic resin. Aluminum paste here refers to aluminum powder that is produced in the presence of mineral spirits and a small amount of higher fatty acids such as stearic acid or oleic acid when making aluminum powder by a known method such as a ball mill method, stamp mill method, or atomization method. It is made into a paste. In the present invention, this aluminum paste and polyolefin thermoplastic resins (various polypropylene resins, various polyethylene resins, EVA resins, EEA resins, EAA resins, etc.) are heated and kneaded, and low volatile substances (mainly mineral spirits with a strong odor) are removed under vacuum. The material removed by a pump etc. is used as aluminum paste compound resin and aluminum paste master batch resin. In particular, the aluminum paste masterbatch resin is used to eliminate harmful effects and odor on photographic materials, and the mineral spirit content in the moisture-proof and light-shielding L-LDPE film layer is increased to 0.1% by weight.
It is also preferable to do the following. For example, even if the mineral spirit content in a masterbatch resin with an aluminum paste content of 40% by weight is 1.0% by weight, if you try to make the aluminum paste concentration in the L-LDPE film layer 2% by weight, the aluminum By kneading 19 parts by weight of natural L-LDPE resin with 1 part by weight of paste master batch, some mineral spirits are removed as gas during film molding in the L-LDPE film layer. The spirit content will be less than 0.05% by weight. As a result, there is no adverse effect on the photographic material, and odor is also reduced. Aluminum powder is made by pulverizing molten aluminum into powder by atomizing, granulating, rotating disk dropping, evaporating, etc., or by crushing aluminum foil into flakes by ball milling, stamp milling, etc. Including things. Since aluminum powder alone is unstable, various known treatments are applied to make the surface of the aluminum powder inert. Known methods for manufacturing metal flakes include USP4469282, Japanese Patent Publication No. 37-6779, Japanese Patent Publication No. 46-6718, etc., and methods for manufacturing metal powder for synthetic resin filling include Japanese Patent Publication No. 59-1989.
There are 75931 etc. L- other than the above-mentioned L-LDPE resin and light-shielding material
The substance that can be included in the LDPE resin light-shielding film layer is preferably high-pressure branched low-density polyethylene (LDPE) resin, but any thermoplastic resin that can be kneaded with L-LDPE resin may be used. Resin can be used. In particular, various polyolefin resins, such as various polyethylene (HDPE, MDPE, LDPE) resins, copolymers with ethylene (ethylene-ethyl acrylate copolymer (EEA), ethylene vinyl acetate copolymer (EVA), etc.) resins, ionomers It is preferable to use one or more of resins, polystyrene resins, polyisobutylene resins, polypropylene resins, etc. in combination. In addition, the L-LDPE resin light-shielding film layer has
In addition to the above-mentioned kneadable thermoplastic resin, various additives can be added in required amounts as necessary. Representative examples of additives are described below, but the present invention is not limited thereto, and any additive can be selected from among all known additives. (Additive types) (Typical examples) (1) Plasticizers: Phthalate esters, glycol esters, fatty acid esters, phosphate esters, etc. (2) Stabilizers: Lead-based, cadmium-based, zinc-based, alkaline earth metal-based, Organotin-based, etc. (3) Antistatic agents; cationic activators, anionic activators, nonionic activators, bifacial activators, etc. (4) Flame retardants; phosphoric esters, halogenated phosphoric esters, halides, inorganic substances, Phosphorus polyol, etc. (5) Fillers: Alumina, kaolin, clay, calcium carbonate, mica, talc, titanium oxide, silica, etc. (6) Reinforcers: Glass roving, metal fiber, glass fiber, glass milled fiber, carbon fiber, etc. 7) Colorants; inorganic pigments (Al, Fe ₂ O ₅ , TiO ₂ ,
ZnO, CdS, etc.), organic pigments (carbon), dyes,
etc. (8) Blowing agents; inorganic blowing agents (ammonia carbonate, sodium bicarbonate), organic blowing agents (nitroso-based, azo-based),
etc. (9) Vulcanizing agents, vulcanization accelerators, accelerators, etc. (10) Deterioration inhibitors; UV absorbers, antioxidants, metal deactivators, peroxide decomposers, etc. (11) Lubricants; Paraffin・Wax, fatty acid-based, silicone-based, stearic acid amide-based, bis-fatty acid amide-based, fatty acid amide-based, alkylamine-based, ester-based, higher alcohol, etc. (12) Coupling agents; silane-based, titanate-based,
Chromium-based, aluminum-based, etc. (13) Various thermoplastic resins, synthetic rubber, etc. As mentioned above, the packaging material for photographic light-sensitive materials of the present invention has an L-LDPE resin light-shielding film layer laminated with another flexible sheet layer. can be made into a composite film. Other flexible sheet layers used in composite films include thermoplastic resin films such as various polyethylene resins, ethylene copolymer resins,
There are known films of polypropylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyamide resin, polycarbonate resin, polyester resin, and films of modified resins thereof. In addition, we also offer thin metal processed films (typically aluminum vacuum-deposited films), cellulose acetate films, cellophane, polyvinyl alcohol films, various papers, various metal foils (typically aluminum foil), non-woven fabrics, warifs,
Also suitable are known flexible sheet layers such as perforated films and foamed sheets of polyethylene, polystyrene, polyurethane, and the like. In the case of forming a composite film, it is preferable that the L-LDPE resin light-shielding film layer kneaded with L-LDPE resin be disposed as the innermost layer in contact with the product. This L-
The LDPE resin light-shielding film layer may be part of an inflation film obtained by coextruding two or more layers. This flexible sheet layer may be one layer, or two or more layers may be combined. Among the flexible sheet layers, a metal thin film processed flexible sheet layer which is particularly suitable for packaging photographic materials will be described in detail. The metal thin film can be formed on both sides or one side (for example, one side of the light-shielding layer side) of the flexible sheet by a conventionally known thin film forming method such as a vacuum evaporation method, a sputtering method, an ion plating method, or an electron beam evaporation method. The most common method is aluminum vacuum deposition. Metal thin films include Al, Sn, Zn, Co, Cr, Ni, Fe,
Single metals such as Cu, alloys, and other metals that can be used to form thin films can all be used, and aluminum (Al) is particularly suitable for its cost and ease of processing.
Various known heating methods such as electric resistance heating, electron beam heating, and high frequency heating may be used to vacuum deposit aluminum. Metal thin films have physical strength as a laminate, light shielding properties,
A thickness of 55 to 1200 Å is preferable from the viewpoint of ensuring antistatic and moisture-proof properties, cost, and quality. That is, the thickness is 55 Å
If the metal thin film processing is less than that, the metal thin film processing flexible sheet layer alone cannot reduce the charge generated on the metal on both sides of the metal thin film, and the thickness must be increased by adding the flexible sheet layer and the light shielding layer on both sides of the metal thin film. It is not possible to ensure the moisture-proofing and light-shielding properties required for packaging materials. If the thickness exceeds 1200 Å, antistatic, moisture-proof, and light-shielding properties can be ensured, but due to cost and vacuum evaporation methods, the flexible sheet layer may deteriorate due to heating.
There are problems such as a decrease in the physical strength of the resulting laminated film, making it difficult to put it into practical use. In the case of an aluminum vapor deposited film, the thickness is preferably 70 Å or more, 80 to 800 Å for normal use, and more preferably 100 to 600 Å. If necessary, a protective layer may be provided on the metal thin film. As the metal thin film protective layer, appropriate resins such as acrylic resins, cellulose resins such as acetic acid fibers, urethane resins, epoxy resins, polyester resins, ionomer resins, EEA resins, various polyethylene resins, and polypropylene resins can be used. Further, wax, gelatin, polyvinyl alcohol, etc. can also be used. The protective layer of metal thin film is preferably formed to have an extremely thin thickness. Even if you make money with extrusion lamination method
If the thickness is not 50 μm or less, static electricity will not be removed sufficiently. By a known solution coating method or spray coating method, etc.
A thickness of 5 μm or less can protect the metal thin film and is highly effective in removing static electricity. Flexible sheet layer, L-LDPE resin light shielding film layer, adhesive layer,
It is also possible to mix antistatic agents, metal powders such as carbon black, aluminum powder, and aluminum base, and conductive substances such as carbon fibers into the metal thin film protective layer, and in this way, static electricity can be removed even more completely. . The flexible sheets may be laminated using conventional methods, such as thermal bonding (hot plate bonding, impulse bonding, ultrasonic bonding), methods using adhesives (wet lamination, dry lamination, hot mill lamination, etc.). (including extrusion lamination method and co-extrusion lamination method), etc. are used. Typical adhesives include polyolefin thermoplastic resin hot melt adhesives such as various polyethylene resins and various polypropylene resins, ethylene-propylene copolymer resins, ethylene-vinyl acetate copolymer resins, and ethylene-ethyl acrylate resins. Ethylene copolymer resin such as polymer resin, ethylene-
There are thermoplastic resin hot-melt adhesives such as acrylic acid copolymer resins and ionomer resins, and other hot-melt rubber adhesives.As solution adhesives, there are wet laminating adhesives, emulsion and latex adhesives. It is a drug. Typical examples of emulsion adhesives include polyvinyl acetate, vinyl acetate-ethylene copolymer, vinyl acetate and acrylic ester copolymer, vinyl acetate and maleate ester copolymer, acrylic copolymer, and ethylene-acrylic acid. There are emulsions such as copolymers. Typical examples of latex adhesives include rubber latexes such as natural rubber, styrene butadiene (SBR), acrylonitrile butadiene (NBR), and chloroprene (CR). Adhesives for dry lamination include polyurethane adhesives, as well as hot melt laminate adhesives blended with paraffin wax, microcrystalline wax, ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer resin, etc. Known adhesives such as adhesives, pressure-sensitive adhesives, and heat-sensitive adhesives can be used. More specifically, polyolefin adhesives for extrusion include various polyethylene resins, polypropylene resins, polybutylene resins, copolymers made of polyolefin resins, ethylene copolymers (EVE, EEA, etc.), and L-LDPE. Like resins, ethylene is partially copolymerized with other monomers (α-olefin), ionomer resins (ionic copolymers) such as DuPont's Surlyn, Mitsui Polychemical's Halamine, and Mitsui Petrochemical (ionic copolymers). Admer (adhesive polymer) from Co., Ltd. These adhesives preferably have a melting point 5° or more lower than the flexible sheet layer to be laminated. If there is a temperature difference of this degree, it is possible to completely perform thermal melt bonding without adversely affecting the flexible sheet. The thickness of the adhesive layer obtained by extrusion lamination using thermoplastic resin is usually 8μm to 50μm.
m is preferably 10 μm to 20 μm, but the cost,
Since it is determined based on the lamination speed, the total thickness of the laminate, etc., it is not particularly limited to this value. Hereinafter, typical embodiments of the present invention will be described with reference to cross-sectional views, but the present invention is not limited thereto. 1 to 8 are cross-sectional views of the product of the present invention. Figure 1 shows the most basic light-shielding material of the present invention, 1L-LDPE resin made by copolymerizing ethylene and butene-1 having 4 carbon atoms, and ethylene and 4-butene having 6 carbon atoms.
Methylpentene 1 or hexene-1 or carbon number 8
This is a packaging material consisting of a single layer of an L-LDPE resin light-shielding film layer 1 containing 50% by weight or more of an L-LDPE resin mixed with a second L-LDPE resin copolymerized with octene-1. FIG. 2 shows a packaging material made of a laminated film obtained by co-extruding the L-LDPE resin light-shielding film layer 1 and the thermoplastic resin film layer 2 shown in FIG. FIG. 3 shows a packaging material made of a laminated film obtained by coextruding two layers: an L-LDPE resin light-shielding film layer 1 and a thermoplastic resin light-shielding film layer 3 containing a light-shielding substance. FIG. 4 shows a packaging material made of a laminated film in which two L-LDPE resin light-shielding film layers 1 are extruded together. Figure 5 shows a typical example of three-layer co-extrusion, and is a package consisting of a laminated film made by co-extruding three layers: an L-LDPE resin light-shielding film layer 1, an intermediate adhesive layer 4, and a thermoplastic resin light-shielding film layer 3. It is the material. FIG. 6 shows a packaging material made of a laminated film in which an L-LDPE resin light-shielding film layer 1 and a flexible sheet layer 5 are laminated with an adhesive layer 4. FIG. 7 shows an L-
This is a packaging material made of a laminated film on which an LDPE resin light-shielding film layer 1 is laminated. FIG. 8 shows a packaging material made of a laminated film using a metal thin film processed flexible sheet layer 8 in which a metal thin film layer 7 is provided on the flexible sheet layer 5 instead of the metal foil 6 in the example shown in FIG. The packaging material for photographic materials of the present invention includes silver halide photographic materials, diazo photographic materials, photosensitive resins, self-developing photographic materials, diffusion transfer photographic materials, etc. whose quality is destroyed by light, humidity, and gas. It is ideal as a packaging material for photographic materials. When the packaging material for photographic light-sensitive materials of the present invention is applied to the packaging of photographic light-sensitive materials, single-layer flat bags, double-layer flat bags, three-layer flat bags,
Double flat bags, square bottom bags, self-standing bags, single gusset bags, double gusset bags, triple gusset bags, film sheets,
All known forms are possible, such as a leader paper lined inside a moisture-proof box. The bag making method is based on conventionally known plastic film sealing methods such as heat sealing, impulse sheeting, ultrasonic sealing, and high frequency sealing, depending on the properties of the laminated film used. In addition, it is also possible to make bags using an appropriate adhesive, pressure-sensitive adhesive, or the like. A packaging bag formed using the packaging material for photographic materials of the present invention will be explained based on FIGS. 9 and 10. FIG. 9 is a partial cross-sectional view of the four-sided heat seal packaging bag 11. This packaging bag 11 uses two approximately rectangular packaging materials, and has a heat-sealed portion 12 whose peripheral edges are bonded together by heat-sealing.
It has become so. FIG. 10 is a sectional view of a packaging bag 15 made up of an outer paper 13 and an inner paper 14, and reference numeral 20 is a photographic material. The outer paper 13 is made of a packaging material or the like shown in the partial cross-sectional views of FIGS. 11 to 13. FIG. 11 shows a laminated film in which a flexible sheet layer 5 and a thermoplastic resin film layer 2 are laminated. FIG. 12 shows a laminated film in which a thermoplastic resin light-shielding film layer 3 is laminated onto a flexible sheet layer 5. Figure 13 shows adhesive layer 4 on flexible sheet layer 5.
This is a laminated film in which a thermoplastic resin light-shielding film layer 3 is laminated. The inner paper 14 is made of the packaging material of the present invention shown in the partial cross-sectional views of FIGS. 1 to 8. These outer paper 13 and inner paper 14 are heat-sealed at the center and at the ends, and then continuously or partially glued at the ends, folded together, and glued together with tape 16. It is pasted and sealed. [Function] The packaging material for photographic materials of the present invention requires a light-shielding substance, ethylene-butene-1 copolymerized L-LDPE resin, ethylene-hexene-1 or ethylene-4-methylpentene-1, or ethylene-octene-1. L- mixed with other substances in a specific ratio by
This is a packaging material that has one or more LDPE resin light-shielding film layers. In addition, many properties have been improved, including lubricity, tear strength, impact drilling strength, heat sealability, heat seal strength, aging and low temperature heat seal strength, light shielding properties, impurity sealing properties, cut sealing properties, slitting suitability, processing machine suitability, etc. I'm letting you do it. Moreover, using an energy-saving process and inexpensive butene-1, L-
Since it uses LDPE resin, it is also cheaper than conventional packaging materials. [Example] Preferred embodiments of the present invention and their effects will be described below. Product of the present invention The product of the present invention corresponds to the embodiment shown in FIG.
It consists of a single layer of LDPE resin light-shielding film layer 1. This L-LDPE resin light-shielding film layer 1 contains 3% by weight of oil furnace carbon black as a light-shielding substance, and the first L-LDPE resin has a melt index of 0.9 g/10 minutes and a density of 0.924 g/cm ³ . NUC polyethylene-LL NUCG0171 made by Nippon Unicar manufactured by low-pressure gas phase method at 47.0
% by weight, as the second L-LDPE resin, the melt index is 2.1 g/10 minutes and the density is 0.92 g/ ^cm3 .
The composition is 50% by weight of 2020L, and is made by an inflation film molding method with a blow ratio of 1.7 and a thickness of 100 μm. Product of the present invention The product of the present invention corresponds to the embodiment shown in FIG.
It consists of a single layer of LDPE resin light-shielding film layer 1. This L-LDPE resin light-shielding film layer 1 contains 3% by weight of oil furnace carbon black as a light-shielding substance, and the first L-LDPE resin has a melt index of 0.8 g/10 minutes and a density of 0.92 g/cm ³ . 47% by weight of Linirex A1210 manufactured by Nippon Petrochemical Co., Ltd. manufactured by low-pressure solution method, No. 2 L-LDPE
As a resin, Urtozex 3502L made by Mitsui Petrochemical's low-pressure solution method, which has a melt index of 2.1 g/10 minutes and a density of 0.935 g/ ^cm3 , was used as a resin with a composition of 50% by weight and a blow ratio of 1.7 and a thickness of 100 μm. This is based on the flasion film molding method. Product of the present invention The product of the present invention corresponds to the embodiment shown in FIG.
It is formed by laminating two layers of an LDPE resin light shielding film layer 1 and a thermoplastic resin light shielding film layer 3 by co-extrusion. A thermoplastic resin light-shielding film layer 3 is used as the surface layer of the product of the present invention, and this thermoplastic resin light-shielding film layer 3 is made of melt index, which is a copolymer of ethylene and 4-methylpentene having 6 carbon atoms. Density is 0.935 at 2.1g/10 minutes
The composition consisted of 98% by weight of Urtozex ^3520L produced by Mitsui Petrochemical's low-pressure liquid phase process and 2% by weight of aluminum paste, and had a thickness of 30 μm.
On the other hand, L-
An LDPE resin light-shielding film layer 1 is used, and the L-LDPE resin light-shielding film layer 1 contains 3% by weight of oil furnace carbon black as a light-shielding substance and a melt index of 0.8 g/l as the first L-LDPE resin. Nippon Petrochemical's low-pressure solution method Linirex has a density of 0.92 g/cm ³ in 10 minutes.
A1210 is 47% by weight, the second L-LDPE resin has a melt index of 2.1g/10 minutes, and a density of 0.92g/10 minutes.
cm ³ , made of Mitsui Petrochemical's low-pressure solution method Urtozex 2020L, with a composition of 50% by weight, and the thickness is
It is 70 μm. Comparative product The comparative product corresponds to the embodiment shown in FIG.
Melt index, which is LDPE resin, is 4g/10
47.0 wt ^.
The second L-LDPE resin, Melt Index,
2.1 g/10 minutes, the composition is 50% by weight of Urtozetsu #3521L manufactured by Mitsui Petrochemical's low pressure liquid phase method with a density of 0.935 g/ ^cm3 , and the blow ratio is 1.7 and the thickness is 100 μm.
It is made using the inflation molding method. Conventional product The conventional product corresponds to the conventional example shown in Figure 14, and the oil furnace carbon black is 3% by weight.
The LDPE resin light-shielding film layer 21 is a single film layer containing 97% by weight of LDPE resin. Conventional product The conventional product corresponds to the conventional example shown in FIG. This contains 3% by weight of oil furnace carbon black and 0.05% by weight of olefinic acid amide, a lubricant.
An aluminum metal foil 6 with a thickness of 7 μm is laminated on the innermost LDPE resin light-shielding film layer 21 with a thickness of 70 μm via an LDPE resin extrusion adhesive layer 4 with a thickness of 15 μm, and further with a thickness of 15 μm.
This packaging material has a five-layer structure, in which a flexible sheet layer 5 of the same bleached kraft paper of 34.9 g/m ² is laminated as the outermost layer via an LDPE resin extrusion adhesive layer 3. Conventional product The conventional product corresponds to the conventional example shown in FIG. This is a conventional product (however, the thickness of the LDPE light-shielding film layer 21 was 50 μm), and the LDPE resin light-shielding film layer 21 with a thickness of 50 μm is further added to the flexible sheet layer 5 via the LDPE extrusion adhesive layer 3 with a thickness of 15 μm. It is a packaging material with a seven-layer structure. Although the above examples are representative examples of preferred embodiments of the packaging material for photographic materials of the present invention, the present invention is not limited thereto, and may contain other known substances. Also, combinations with other known materials, flexible sheet layers, etc. are possible. Tables 1 to 3 show the results of comparing the layer structure, materials used, thickness of each layer, and characteristics of the products of the present invention, comparative products, and conventional products. In the above example, the LDPE extrusion adhesive layer 4 is Mirason manufactured by Mitsui Polychemical Co., Ltd.
14 (MI 5.1 g/10 min, density 0.919 g/cm ³ ) and the carbon black was Mitsubishi Kasei Oil Furnace Carbon Black 44B (average particle size 21 mμ,
PH7.7) and the LDPE resin light-shielding film layer was DFD-0111 manufactured by Nippon Unicar (MI 2.4g/10min, density
0.923 g/cm ³ ) was used, respectively.

【table】

Claims (1)

[Scope of Claims] 1. A first straight film having a melt index of 0.2 to 5.0 g/10 minutes and a density of 0.870 to 0.940 g/cm ^{3 ,} which is made by copolymerizing ethylene with butene-1 having 4 carbon atoms. Chain low density polyethylene resin is 5-80% by weight, melt index is 0.5-10g/10 minutes, density is 0.870-
A second linear low-density polyethylene resin of 0.940 g/cm ³ in which ethylene is copolymerized with 4-methylpentene-1 or hexene-1 having 6 carbon atoms, or octene-1 having 8 carbon atoms. At least one layer of a linear low-density polyethylene resin light-shielding film layer containing 50% by weight or more of a linear low-density polyethylene-based resin having 20-95% by weight and 0.1-10% by weight of a light-shielding substance. A packaging material for photographic materials characterized by: 2. The packaging material for photographic materials according to claim 1, wherein the first linear low-density polyethylene resin is formed by a low-pressure vapor phase method. 3. The photographic photosensitive material according to claim 1 or 2, wherein the light-shielding substance is carbon black, and 50% by weight or more of the carbon black is furnace carbon black with a pH of 5 to 9 and an average particle size of 10 to 120 mμ. Packaging materials for materials.