JPH0687138B2 - Packaging bag for photosensitive material and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a packaging bag suitable for a photosensitive material, particularly a photographic photosensitive material, and a method for producing the same.

[Conventional technology]

Generally, for light-sensitive materials, such as those that lose their quality value when exposed to light, a packaging bag that completely blocks light is used. In addition to the above-mentioned light-shielding property, the packaging bag must have sufficient physical strength according to the size and weight of the object to be packaged, that is, tensile strength, tear strength, burst strength, etc., and the opening should be sealed by heat sealing. Therefore, heat sealing suitability is required. Further, antistatic property is also required to prevent electrostatic charge due to friction between the photosensitive material and the packaging bag.

Conventionally, as a laminated film used for such a packaging bag, there has been one as shown in FIGS. 15 and 16.

The laminated film shown in FIG. 15 has a low-density polyethylene (hereinafter referred to as LDPE) resin layer 18a containing a light-shielding substance,
A metal foil layer 15 and a flexible sheet layer 19 are sequentially laminated with an adhesive layer 16.

The laminated film shown in FIG. 16 is obtained by laminating an LDPE resin layer 18a containing a light-shielding substance further on the flexible sheet layer 19 side of the laminated film shown in FIG. 15 via an adhesive layer 16.

In addition, in Japanese Utility Model Publication No. 56-19087 relating to the present applicant, a composite of two uniaxially stretched high-density polyethylene cloth laminate films and low-density polyethylene films whose stretching directions are mutually at an angle of 45 ° to 90 °. A packaging bag for light-sensitive materials using a laminated film was proposed, and the same was
In 61-20590, a high-density polyethylene film is uniaxially stretched at a stretching ratio of 2.2 to 4.2 times, and the stretching axis is 45
A packaging material for a photosensitive material using a composite laminate sheet in which two or more layers are laminated so as to form an angle of 90 ° to 90 ° has been proposed.

[Problems to be Solved by the Invention]

However, the conventional composite laminated film of LDPE resin film and paper, aluminum foil, cellophane, etc., is used as a thick film because of its poor physical strength, and is therefore rigid and bulky, heavy and expensive.

In addition, the proposal by the applicant of the present invention also has improved physical strength, improved light-shielding properties, reduced thickness and reduced cost compared to the composite laminate film of the low-density polyethylene film, but at present, physical strength is further improved. However, there is a need for a large, flexible, heat-insulating, moisture-proof, light-shielding, curling-free, and more inexpensive product.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, to provide a packaging bag for a photosensitive material which is improved in various performances and is inexpensive, and a method for producing the same.

[Means for Solving the Problems]

The present invention has been made in order to achieve the above-mentioned object, and has been solved by providing a packaging bag with a double-layer structure of a thin film.

That is, the packaging bag for photosensitive material of the present invention is a bag having two open end portions forming an opening portion into which a photosensitive material is inserted, melt-bonded portions at both ends, and a bottom portion, and the bags are separated from each other. formed a light-shielding material which is in the outer film and an inner film comprising ^{0.5g / m 2 ~50g / m 2} , one of the opening end portion folded back and the outer film and inner film integrally and continuously While the bent part is formed, the other part is formed with a cut part where the cut end surfaces of the outer film and the inner film are exposed, and the cut part projects from the bent part to form the tongue part. It is configured as a feature.

The first method for producing a packaging bag for a photosensitive material is as follows. The inner surface of a ring formed by cutting a cylindrical multi-layer coextrusion blown film into slices is overlapped, and the outer film and the inner side, which are continuous uncut portions at both ends, are joined together. A flat rectangular film consisting of a film is formed, and one of the non-cut parts of this rectangular film is folded back to the front of the opposite non-cut part to form a bent part, and between the two non-cut parts. In, the outer film and the inner film are cut parallel to the non-cut portion to form a cut portion, and then the outer film and the inner film on both sides are melt-bonded.

Further, the second method for producing a bag for photosensitive material is one in which a rectangular laminated film is folded back to form a film having an outer film and an inner film and one end of which is a cut portion. It is characterized in that the end portion of the film on the side opposite to the cut portion is further folded back so as to be located inside the cut portion to form a bent portion, and then the outer film and the inner film on both sides are melt-bonded.

In addition, if the double film is not continuous and the films are separated, the cut portion may be melt-bonded discontinuously or continuously melt-bonded to be integrated.

The tongue is for surely finding an opening for inserting an object to be contained in a dark room, and may have a length that can be checked by a fumbling.

An inflation film or a laminated film formed by the T-die method or the like is used as the packaging bag for the photosensitive material.
When an inflation film is used, this inflation film is a multi-layer coextrusion inflation film having two or more outer layers and at least one inner layer containing a light-shielding substance (hereinafter referred to as an inflation frame).
And, it is used in a form where the inner layers are in contact with each other.

The thermoplastic resin used for the blown film can be melt-bonded to polyethylene resin, ethylene-modified resin, polypropylene resin, ethylene copolymer resin, soft vinyl chloride resin, polyester resin, polyamide resin, etc., and is made into a multi-layer coextrusion blown film. Any thermoplastic resin that can be used can be used. However, it is a thin film, has strength, has appropriate hardness, is easy to handle, has excellent moisture resistance, water resistance, chemical resistance, and is inexpensive polyethylene resin, especially linear low-density polyethylene (hereinafter L-
Resins designated as LDPE) are most preferred.

Therefore, in the packaging bag of the present invention, both the outer layer and the inner layer have excellent heat-sealing properties, so that a multilayer coextrusion blown film containing an ethylene copolymer resin is preferably used. In that case, it is preferable to contain at least 10% or more of ethylene copolymer resin in consideration of heat sealing suitability, improvement of physical strength and the like.

If the outer layer is a resin having a higher melting point than the inner layer, bag-making suitability is improved, melt adhesion strength is increased, and appearance is also improved. Therefore, the outer layer is mainly composed of high-density polyethylene (hereinafter referred to as HDPE) resin, and the inner layer is Preferably has an ethylene copolymer resin as a main component.

At this time, it is also preferable to use L-LDPE resin as the main resin component of the inner layer / outer layer and blend the HDPE resin with the outer layer.

In the present invention, it is also possible to use a uniaxial (longitudinal, lateral or oblique) molecularly oriented thermoplastic resin inflation film.

If necessary, in addition to the outer and inner two-layer inflation film, a multi-layer coextrusion inflation film having three or more layers including an intermediate layer is used.

The polyolefin resin used for the blown film is HDPE resin, MDPE resin, LDPE resin, depending on the manufacturing method.
L-LDPE resin, ethylene copolymer resin, ethylene modified resin, polypropylene resin, etc.

LDPE resin can be divided into two types, tube method and autoclave method, according to the manufacturing process.

The LDPE resin has a density of 0.915 to 0.930 g / cm ³ and an MI of 0.2 g / 10 minutes or more, preferably 0.5 g / 10 minutes or more.

L-LDPE resin is called the third polyethylene resin and has the advantages of both medium and low pressure method and high pressure method polyethylene resin.
It is a high-strength resin. This resin is generally a low-pressure method, and ethylene and α-containing 3 to 13 carbon atoms, preferably 4 to 8 carbon atoms.
It is a copolymer of olefins and is a low to medium density polyethylene resin having a linear straight chain with a short branch having an ethylene content of 85 to 99.5 mol%. Recently, L-LDPE resin, which is a high-pressure improved method, has also become commercially available.

As the α-olefin, butene-1, octene-1, hexene-1, 4-methylpentene-1, heptene-1,
Etc. are used, and the amount thereof is about 0.5 to 15 mol% of the polymer. Density is generally considered to be low to medium density polyethylene resin, but most commercial products have a density within the range of 0.87 to 0.95 g / cm ³ .

A concrete example of L-LDPE resin is G resin (UCC
Company), Dow Rex (Dow Chemical Company), Sclere (Dupont Canada Company), Marrex (Phillips Company), Neo-Zex and Ulto-Zex (Mitsui Petrochemical), Nisseki Linilex (Nippon Petrochemical), Stamirex (DSM) , And so on.

Among these L-LDPE resins, particularly preferable in terms of physical strength and heat seal strength, ethylene content is 90 to 99.5.
Mol%, α-olefin content 0.5 to 10 mol%, melt index (hereinafter referred to as MI) 0.8 to 30 g / 10 minutes (JIS
K6760), a density of 0.870 to 0.940 g / cm ³ (JIS K 6760), and an α-olefin having 6 to 8 carbon atoms, which are obtained by a liquid phase method and a gas phase method process.

A particularly preferred representative example is the trade name of Ultzex and α-olefin side chain of Mitsui Petrochemical Co., Ltd. in which 4-methylpentene-1 having 6 carbon atoms is introduced into ethylene as an α-olefin side chain. Examples include Stamilex of DSM Co., which introduced octene-1 having 8 carbon atoms, Dowlex of Dow Chemical Co., and Moatech of Idemitsu Petrochemical Co., Ltd. (The above four companies obtained the liquid phase process L -LD
It is a PE resin. ).

In order to impart a light-shielding property to the multilayer coextrusion blown film, it is necessary to include a light-shielding substance in at least one layer.

The light-shielding substance refers to a substance that can be kneaded or dispersed in each layer and does not transmit visible light, ultraviolet light, or the like. As the light-shielding substance usable in the present invention, various carbon blacks,
Graphite, iron oxide, zinc oxide, titanium oxide, clay,
Aluminum powder, aluminum paste, calcium carbonate, mica, barium sulfate, talc, cadmium-based pigment, rouge, cobalt blue, copper phthalocyanine-based pigment,
Examples thereof include monoazo or polyazo pigments, organic pigments such as aniline black, and inorganic pigments.

It is preferable that the light-shielding substance is contained in an amount of 0.1 to 20.0% by weight.

If it is less than 0.1% by weight, the effect of adding a light-shielding substance (securing of light-shielding property, antistatic property, etc.) cannot be expected, and the cost is increased by the kneading cost.

If it exceeds 20.0% by weight, the physical strength of the thermoplastic resin film, particularly the tear strength, will lower the impact puncture strength and the heat sheet properties will deteriorate.

Further, the light-shielding substance on the surface of the film frequently contaminates the light-sensitive substance or the light-shielding substance is detached from the film and adheres to the light-sensitive substance.

It is also preferable to mix two or more light-shielding substances according to the required characteristics. Even in this case, carbon black with an average particle size of 200 mμ or less was used per unit area (m ² ) of the packaging material.
It is preferred as a photosensitive material for a packaging material containing ^{5g / m 2 ~50g / m 2} . On the other hand, among these carbon blacks, pH5
~ 9, average particle size of 10 ~ 120mμ is preferred,
Furnace carbon black having a pH of 6 to 9 and an average particle diameter of 50 mμ or less is preferable. By using such a pH and particle size, the fog is less likely to occur, the increase or decrease in the photosensitivity is less, the light-shielding ability is great, and pinholes due to carbon black lumps (fish) or fish eyes are generated. It is possible to obtain a packaging material that has various advantages such as being less likely to occur and improving physical strength and heat seal suitability.

There are various forms of blending the light-shielding substance as described above,
The masterbatch method is preferable in terms of cost reduction, prevention of workplace contamination, and the like.

Next to the carbon black, a metal powder that is preferable as a light shielding material will be described. This metal powder is a light-reflecting light-shielding substance that gives it a silver-colored, highly commercialized appearance, and is excellent in many points such as moisture resistance, light-shielding property, antistatic property, heat resistance under sunlight, and gas barrier property. There is.

As the metal powder, a substance obtained by removing a low volatile substance from aluminum powder or aluminum paste and kneading with a thermoplastic resin is particularly preferable.

The aluminum paste here means the presence of mineral spirits and a small amount of higher fatty acids or fatty acid compounds such as stearic acid or olefinic acid when producing aluminum powder by a known method such as a ball mill method, a stamp mill method, or an atomizing method. It is made in paste form based on. In the present invention, this aluminum paste and polyolefin thermoplastic resin (various polypropylene resins, various polyethylene resins, EVE resin, EEA resin, EAA resin, etc.) are heated and kneaded, and low volatile substances (mainly mineral spirits with a strong malodor) are heated and kneaded. It is preferable to use those removed by a vacuum pump or the like as an aluminum paste compound resin or an aluminum paste masterbatch resin in order to eliminate adverse effects on a photographic light-sensitive material and a bad odor. For example, even if the content of mineral spirits in the masterbatch resin of 40% by weight of aluminum paste is 1.0% by weight, if the concentration of aluminum paste in the film layer is set to 2% by weight, 1% by weight of the aluminum paste masterbatch will be used. Since 19 parts by weight of the natural resin is kneaded to the parts, and the mineral spirit is removed as a gas during the film formation in the film layer, the mineral spirit content is 0.05% by weight or less. As a result, the photographic light-sensitive material is not adversely affected and the bad odor is also reduced.

In addition to aluminum powder, in addition to powdered molten aluminum by atomizing method, granulating method, rotary disc dropping method, evaporation method, etc., aluminum foil is crushed by ball mill method, stamp mill method or the like into flakes. Including things and short aluminum fibers. Since the aluminum powder alone is unstable, various known treatments for inactivating the surface of the aluminum powder are performed. Particularly, those which are surface-treated with various fatty acids, fatty acid compounds and coupling agents are preferable because they have excellent dispersibility and antistatic properties.

If you want more light shielding, the inner layer and the outer layer or more,
A light-shielding substance can be contained in all layers including the intermediate layer. Further, the outer layer contains a metal powder which is a light-reflecting substance, for example, a low volatile substance removal product of aluminum powder or aluminum paste, and the inner layer contains carbon black which is a light-absorbing light-shielding substance to further enhance the light-shielding effect. It is preferable to increase.

In addition, lubricants, antistatic agents, antioxidants and the like are added as additives to the multi-layer coextrusion blown film.

The representative lubricants and their manufacturer names are listed below.

(1) Silicone lubricant; various grades of dimethylpolysiloxane and its modified products (Shin-Etsu Silicone, Toray Silicone), etc. (2) Oleic acid amide lubricant; Armoslip CP (Lion Akzo), Neutron (Nippon Seika) , Neutron E-18 (Nippon Seika), Amide O (Nitto Kagaku), Alflo E-10 (Nippon Yushi), Diamid O-200 (Nippon Kasei), Diamid G-200 (Nippon Kasei), etc. (3 ) Erucamide amide lubricant; Alflo P-10 (Nippon Oil & Fat), Neutron S (Nippon Seika), etc. (4) Stearic acid amide lubricant; Alflo S-10 (Nippon Oil and Fat), Neutron 2 (Nippon Seika) ), Diamond
200 (Nippon Kasei), etc. (5) Bis fatty acid amide lubricants; Bisamide (Nippon Kasei), Diamid 200 bis ((Nippon Kasei), Armowax EBS (Lion Akzo), etc. (6) Alkylamine lubricants: Electrostripper −
TS-2, electrostripper TS-3 (Kao soap), etc. are available.

When used for packaging photographic light-sensitive materials, the preferable amount of lubricant that does not adversely affect them is 0.01 to 2.0% by weight.
Therefore, not only the single addition but also two types may be used in combination.
The fatty acid amide-based lubricant preferred in the present invention has 8 to 50 carbon atoms.
Ke: Particularly preferable is 15 to 35 pieces.

As the antistatic agent, anionic type alkyl phosphate ester, cationic type alkyl amine derivative, quaternary ammonium salt, amphoteric type imidazoline type metal salt, nonionic type polyoxyethylene alkyl amine, polyamine Oxyethylene fatty acid ester, polyoxyethylene ethylene alkyl ether and the like are used.

The following are antioxidants.

Phenolic n-octadecyl-3 (3 ', 5'-di-t-butyl 4'
Hydroxyphenyl) propinate, 2,6 di-t-butyl 4-methylphenol, 2,6 di-t-butyl-p-cresol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4 4,4'-thiobis (3-methyl 6-t-butylphenol, 4,4'-butylidene bis (3-methyl-6-t-butylphenol), stearyl-β (3,5-di-4-butyl 4-hydroxyphenyl) ) Propionate, 1,1,3-tris ((2-methyl-4-hydroxy-5-
t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3 (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate) methane, etc. Sulfur-based dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, laurylstearylthiodipropionate , Distearyl-3'-thiodipropionate, ditridecyl-3,3'-thiodipropionate, phosphorus-based trinonylphenyl phosphite, triphenyl phosphite, etc., especially 2,6-di-tbutyl-p- Cresol (BHT) and low volatility high molecular weight phenolic antioxidant (brand name lregan
ox 1010, lriganox 330, To-pano ICA, etc.), dilauryl thiodipropionate, distearyl thiodipropionate, dialkis phosphate, etc., and it is effective to use one or more, especially two or more thereof in combination.

The addition amount is preferably 0.001 to 1.0% by weight whether used alone or in combination of two or more kinds. Addition amount 0.001
If it is less than wt%, the effect of addition is almost negligible. On the other hand, if the amount added exceeds 1.0% by weight, the photographic film utilizing the oxidation and reduction effects may be adversely affected and the performance may be abnormal. For this reason, it is preferable to add the antioxidant in the minimum amount that does not cause coloration failure or spots. Particularly preferred are phenolic antioxidants, and as commercial products, various Irganox products manufactured by Ciba Geigy and Sumitomo Chemical Co., Ltd.
Sumilizer BHT, Sumilizer BP-76, Sumilizer WX-R, Sum
ilizer BP-101 etc.

The antioxidants may be used alone or in combination of two or more. Further, when used in combination with carbon black or the like, the antioxidant effect is synergistically exhibited.

When a laminated film is used, this laminated film has a thermoplastic resin layer laminated on both sides so that it can be melt-bonded. For this thermoplastic resin layer, polyethylene resin, ethylene-modified resin, polypropylene resin, ethylene copolymer resin, soft vinyl chloride resin, polyester resin, polyamide resin or the like is used.

As the laminated film, various laminated films in which a metal foil, a metal vapor deposition film paper, a nonwoven fabric, a foamed sheet and the like are laminated are used as long as the thermoplastic resin layers are laminated on both sides.

The light-shielding substance, lubricant, antistatic agent, antioxidant and the like added to the laminated film are the same as in the case of the inflation film.

In the bag making method for the first packaging bag for photosensitive material, when one of the bent portions of the non-cutting portion of the inflation film is folded back in parallel so as to be located inside the opposite bent portion,
If the blown film is large enough, you can fold it from both sides and get two bags at a time. Further, when making packaging bags of various depths from the same inflation film, the folding length is changed when the folding portion is folded back.

In this bag-making method, the inflation film produced by the multi-layer co-extrusion inflation film production apparatus is used directly or the wound inflation film is transversely cut to the width of the bag and used.

The blown film is cut by mechanical cutting, heat cutting (cut seal) used for both sealing and cutting using a hot plate knife, a hot wire, or the like.

The second method for producing a packaging bag for a photosensitive material is such that when a packaging bag of various sizes is used, even if a laminated film cut in advance to a predetermined size is used, it is folded back fourfold. The folding back length may be changed and the excess laminated film may be cut off.

In the both bag making methods, melt adhesion is hot bar seal, hot roll seal, impulse seal, hot air seal, heat melt seal, hot knife cut seal,
It is heat-sealed by a high frequency seal, an ultrasonic seal or the like. There is also a method in which the folding device and the fusion bonding device are incorporated into one device, and folding and welding are performed at the same time.

The packaging bag for a photosensitive substance of the present invention is a silver halide photographic light-sensitive material, a diazo photographic light-sensitive material, a photosensitive resin, a self-developing photographic light-sensitive material, a diffusion transfer type photographic, the quality of which is destroyed by slight gas, light or humidity. It is most suitable for photographic light-sensitive materials such as light-sensitive materials. In addition, it can be used not only for photographic light-sensitive materials, but also for packaging of all light-sensitive materials such as pharmaceuticals, chemical substances, foods, etc., which are required to have a light-shielding property and low dust-generating property and whose quality is deteriorated by light.

Further, the method for producing a packaging bag of the present invention can be applied not only to the production of a packaging bag for a photosensitive material but also to the production of all packaging bags using a multilayer film.

[Action]

Since the packaging bag of the present invention has a double structure of the outer film and the inner film, the curling is small, the physical strength (tear strength, impact punching strength, etc.) is large, the weight can be reduced, and the packaged object is packaged. I am familiar with the time.

In the first bag-making method of the present invention, since the multilayer co-extrusion inflation film is folded and cut, the double bag is extremely easily made. Also, by changing the folding length, packaging bags of various depths are manufactured.

In the second bag manufacturing method of the present invention, since the laminated film is folded back, the double bag is manufactured very easily.

〔Example〕

An embodiment of the photosensitive material packaging bag of the present invention will be described with reference to FIG.

FIG. 1 is a partially cutaway perspective view of a packaging bag for photosensitive materials. In this figure, reference numeral 1 is an opening end portion, and a space between the opening end portions 1 and 1 is an opening portion 2 into which an object is inserted. The open ends 1 and 1 are formed so that their tips do not coincide with each other and are slightly spaced apart from each other. The open end 1A on the projecting side of the open end 1 and the outer film 3 and the inner film 4 are melt-bonded only on both sides, The cut portion 5 is open. That is, the opening end portion 1A is in a state where the outer film 3 and the inner film 4 are not adhered to each other in the center thereof but merely overlap each other. Further, the open end portion 1B is a bent portion 6 in which the outer film 3 and the inner film 4 are continuous. That is, the open end portion 1B is a state in which the outer film 3 and the inner film 4 are integrally connected without being cut. Then, the portion of the opening end 1A protruding from the opening end 1B is
It serves as a tongue portion 7 when the photosensitive material is expropriated.

Further, melt-bonded portions 8 and 8 which are completely sealed by melt-bonding are formed at both ends, and the melt-bonded portions 8 and 8 have a double structure of an outer film 3 and an inner film 4.

Examples of the outer film 3 and the inner film 4 will be described with reference to FIGS. 2 to 4.

2 to 3 are partial cross-sectional views of a packaging bag for a photosensitive material using an inflation film.

In FIG. 2, the outer film 3 and the inner film 4 are formed of an integral inflation film, and the outer film 3 and the inner film 4 are outer layers containing a light-shielding substance.
It is composed of 11a and inner layer 12a, and has a double structure in which inner layers 12 and 12a are in contact with each other.

In FIG. 3, the outer film 3 and the inner film 4 are formed of an integral inflation film, and the outer film 3 and the inner film 4 are laminated between the outer layer 11a and the inner layer 12a containing a light-shielding substance. Midlayer 13
It has a double structure consisting of the inner layers 12a and 12a in contact with each other.

FIG. 4 is a partial cross-sectional view of a photosensitive material packaging bag using a laminated film. In this figure, the outer film 3 and the inner film 4 are formed of an integral laminated film,
The outer film 3 and the inner film 4 are films in which the thermoplastic resin layers 17a and 17a to which the light-shielding substance is added are laminated on both surfaces of the metal foil layer 14 via the adhesive layers 16 and 16.

In order to wrap a photosensitive material such as a movie film in the above-mentioned packaging bag for a photosensitive material, the open end 2 is found by groping the tongue portion 7 in a dark room, and the movie film is tongue portion. Store while guiding at 7.

Next, a method for making a bag for a photosensitive material using an inflation film will be described with reference to FIGS. 5 to 8.

First, as shown in FIG. 5, a cylindrical multi-layer coextrusion blown film 21 is cut into a ring so as to correspond to the width of the packaging bag, and the inner surfaces of the rings are overlapped to form a non-cut portion in which both ends are integrally continuous. And an outer flat film and an inner film that are annular and flat rectangular. As shown in FIG. 6, the inflation film 21 is folded back at one non-cutting portion 22 to just before the cutting line 23, and this non-cutting portion 22 becomes the bent portion 6 of the packaging bag. Next, as shown in FIG. 7, it cuts along a cutting line 23, and this cutting portion becomes the cutting portion 5 at the end of the packaging bag, and the portion protruding from the non-cutting portion 22 becomes the tongue portion 7. Then, as shown in FIG. 8a, the cut portions 24, 24 on both sides are melt-bonded to each other to form the melt-bonded portions 8.8, thereby completing the packaging bag. If necessary, the cut portion 5 may be a partial seal by a point seal or a cut seal, and the entire surface may be sealed by a melt-bonding portion 8'as shown in FIG. 8b.

Next, a method for making a bag for a photosensitive material using a laminated film will be described with reference to FIGS. 9 to 12.

First, as shown in FIG. 9, a laminated film 31 is formed into a long shape having a predetermined size by various laminating methods and the like, and then, as shown in FIG. The end portion 33 becomes the cutting portion 5. Furthermore, as shown in FIG.
The end 32 on the side opposite to the cutting portion 5 is folded back again, and this end 32 becomes the bent portion 6, and the portion protruding from the bent portion 6 becomes the tongue portion 7. Then, as shown in FIG. 12, both sides are melt-bonded to each other to form the melt-bonded portions 8 and 8 to complete the packaging bag. If necessary, the cutting portion 5 may be a partial seal, a cut seal, or an entire surface seal by fusion bonding or the like.

FIG. 13 is a partial cross-sectional view showing the layer structure of a comparative example. This comparative example has a single-layer structure of a two-layer coextruded inflation film including an outer layer 11a and an inner layer 12a containing a light-shielding substance.

FIG. 14 is also a partial cross-sectional view showing the layer structure of a comparative example, which is a double structure of a single-layer inflation film of an LDPE resin film layer 18a containing a light-shielding substance.

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

Invention Product I Invention product I corresponds to the layered structure shown in FIG.

The inner layer 12a is a copolymer resin of ethylene and 4-methylpentene-1 (JIS K 6760) 0.920 g / cm ³ , MI
(Metor index; JIS K 6760, hereinafter referred to as MI) 2.1g
/ 10 minutes, Vicat softening point (JIS K 7206) 100 ° C L-LDPE resin 94.75% by weight, oleic acid amide 0.05% by weight, phenolic antioxidant 0.2% by weight, oil furnace carbon black 3.0% by weight, alkylamine type Antistatic agent 2.0
It is an L-LDPE resin system composition consisting of wt%.

The outer layer 11a has a density of 0.951 g / cm ³ , a MI of 1.1 g / 10 min, a Vicat softening point of 126 ° C. of HDPE resin 20.0% by weight, and a density of 0.920 g / cm of a copolymer of ethylene and 4-methylpentene-1. ³ , MI
2.1 g / 10 minutes, 76.95% by weight of L-LDPE resin with a Vicat softening point of 100 ° C., 3.0% by weight of oil furnace carbon black,
A resin composition containing 0.05% by weight of oleic acid amide.
Using the above resin composition, a two-layer coextrusion blow molding film molding machine was used to mold the resin film to a thickness of 30 μm and a total thickness of 60 μm. Subsequently, this was used to make a bag by the first bag making method.

Invention Product II Invention product II corresponds to the layer structure shown in FIG.

The inner layer 12a is a copolymer resin of ethylene and butene-1 with a density of 0.890 g / cm ³ , MI of 1.0 g / 10 min, and a Vicat softening point of 7
This is an L-LDPE resin composition composed of 94.75% by weight of L-LDPE resin at 5 ° C, 0.05% by weight of oleic acid amide, 0.2% by weight of phenolic antioxidant and 3.0% by weight of oil furnace carbon black.

The outer layer 11a is a copolymer resin of ethylene and 4-methylpentene-1, density 0.920 g / cm ³ , MI 2.1 g / 10 minutes, Vicat softening point 100 ° C. L-LDPE resin 96.75 wt%, oleic acid amide. 0.05 wt%, phenolic antioxidant 0.2 wt%,
L consisting of 3.0% by weight of oil furnace carbon black
-LDPE resin type composition.

The resin composition was molded into a film having a thickness of 30 μm and a total thickness of 60 μm using a two-layer coextrusion blown film molding machine. Subsequently, this was used to make a bag by the first bag making method.

Inventive Product III Inventive Product III corresponds to the layer structure shown in FIG.

Inner layer 12a is a copolymer resin of ethylene and ethyl acrylate 18% density 0.930g / cm ³ , MI 6g / 10 minutes, Vicat softening point 56 ℃ ethylene-ethyl acrylate resin 60.0.
% By weight, a copolymer resin of ethylene and octene-1 with a density of 0.920 g / cm ³ , MI of 2.0 g / 10 minutes, and a Vicat softening point of 96 ° C. L
-LDPE resin 34.75% by weight, oleic acid amide 0.1% by weight,
An ethylene-ethyl acrylate resin composition comprising 0.15% by weight of a phenolic antioxidant, 3.0% by weight of oil furnace carbon black, and 2.0% by weight of an alkylamine antistatic agent.

The outer layer 1a has the same composition as 1a of the product II of the present invention. Using the above resin composition, a two-layer coextrusion blower film molding machine was used to mold the resin film to a thickness of 30 μm and a total thickness of 60 μm. Subsequently, this was used to make a bag by the first bag making method.

Inventive Product IV Inventive Product IV corresponds to the layer structure shown in FIG.

The outer layer and the inner layer 17a were two-layer coextrusion blown film having the same resin composition and layer constitution as the product I of the present invention, and each was molded to a thickness of 15 μm and a total of 30 μm.

An LDPE extrusion film 17a having a thickness of 13 μm was laminated on both sides of an aluminum vacuum evaporation film 15 formed by providing a 400 μm thick aluminum vacuum evaporation layer on a biaxially stretched nylon film having a thickness of 15 μm. Subsequently, the laminated films 3 and 4 were used to make a bag by the second bag making method.

Comparative product I Comparative product I corresponds to the layer structure shown in FIG.

The resin composition of the outer layer 11a and the inner layer 12a is the same as that of the product I of the present invention. A two-layer co-extrusion blown film molding machine was used to mold each with a thickness of 60 μm and a total of 120 μm. Subsequently, this was used in a single layer, and the bag was made in the same manner as in the product I of the present invention without any change except that it was used in a single layer.

Comparative product II Comparative product II corresponds to the layer structure shown in FIG.

High-pressure branched low-density polyethylene resin (LDPE resin) 97.0% by weight, oil furnace carbon black 3.0% by weight, resin composition with a density of 0.923 g / cm ³ , MI 2.4 g / 10 min, thickness of 60 μm by inflation film molding machine Molded into. Subsequently, this was used to make a bag by the first bag making method.

Conventional product I Conventional product I corresponds to the layer structure shown in FIG.

LDPE resin film layer with the same composition as Comparative product II and a thickness of 50 μm
18a and aluminum metal foil 15 with a thickness of 7 μm, bleached kraft paper with a basis weight of 35 g / m ² and LDPE resin layer 18a with a thickness of 50 μm are stacked on top of this, and LDPE extrusion with a thickness of 13 μm is provided between each material. A laminated film laminated with the laminate layer 16 interposed therebetween was produced. Subsequently, this was used in a single layer, and the bag was made in the same manner as in the product I of the present invention without any change except that it was used in a single layer.

The experimental results are shown in Table 1.

The evaluation is as follows.

◎… Extremely good ○… Excellent ● …… Yes (within practical limits) ▲… Problems need improvement ×… No practical use * A Bag breaking strength Pack 1 kg of sand into the bag and seal it to 1 m above the floor The number of times that the bag was broken from the height and the bag was torn was calculated.

* B Antistatic property Compare the degree of static electricity generation due to friction when putting in and taking out roll-shaped motion picture film at a specified temperature and humidity.

* C Flexibility Judgment based on the workability when folding the opening or inserting a roll of motion picture film.

* D Tear strength conforms to JIS P8116 * E curling Sensory evaluation of curling in an unloaded state in an atmosphere of blown film and laminated film before bag making at a temperature of 20 ° C and humidity of 65% RH.

〔The invention's effect〕

As described above, since the photosensitive material packaging bag of the present invention uses the film in a double structure, it is a thin film, lightweight, rich in flexibility, large in physical strength and heat insulating. In addition, it is possible to add a lot of light-shielding substances and other additives to the inner layer in a state where the influence on the photosensitive substance is eliminated, and it is excellent in light-shielding property and antistatic effect, has moisture-proof property, and is easy and unreasonable. Because it is created without curling or stretching, it is easy to put in and take out items to be packaged.

Further, the bag manufacturing method for the packaging bag of the present invention can be manufactured at a low price because the bag manufacturing process is simple, and also it is possible to easily manufacture a packaging bag having a different size and shape, in particular, an inflation film. Since the bag-making method used can make packaging bags of various sizes from one type of inflation film,
It is economical because there is no need to form blown films of various sizes.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of one embodiment of a packaging bag for photosensitive material of the present invention, FIGS. 2 to 4 are partial sectional views of the same as above, and FIGS. 5 to 8b are the first of the present invention. 9 to 12 showing a bag manufacturing process of an embodiment of the method for manufacturing a photosensitive material packaging bag of FIG.
The figure shows a bag making process of an embodiment of the method for making a bag for a photosensitive material according to the second invention, and FIGS. 13 to 14 are partial sectional views of a comparative example, FIGS. 15 and 16. The figure is a partial cross-sectional view of a conventional example. 1A, 1B …… Opening end part, 5 …… Cut part 6 …… Bend part, 7 …… Tongue part 8,8 ′ …… Melting bond part 21 …… Inflation film 22 …… Non-cut part, 24 …… Cutting part 31 …… Multilayer film, 32 …… Bending part 33 …… End part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location G03C 3/00 A 8910-2H 590 Z 8910-2H

Claims (3)

[Claims] 1. An opening 2 into which a photosensitive material is inserted.
In a bag having one open end, a melt-bonded portion at both ends, and a bottom, the bag is made of a light-shielding substance which is separated from each other.
Formed between 0.5g / m ² ~50g / m ² outer film comprising an inner film, one of the opening end portion folded back and the outer film and the inner film is formed bent portion which is integrally continuous On the other hand, the other is formed with a cut portion where the cut end faces of the outer film and the inner film are exposed, and the cut portion projects from the bent portion to form a tongue portion. bag 2. A flat rectangular film composed of an inner film and an outer film, which is a non-cutting portion in which both ends are integrally continuous, by stacking the inner surfaces of rings formed by cutting a cylindrical multi-layer coextrusion inflation film into slices. To form
Fold one of the non-cutting parts of this rectangular film forward from the opposite non-cutting part to form a bent part,
A packaging bag for a photosensitive material, characterized in that the outer film and the inner film are cut between the two uncut portions in parallel with the uncut portion to form a cut portion, and then the outer film and the inner film on both sides are melt-bonded. Bag making method 3. A rectangular laminated film is folded back to form a film composed of an outer film and an inner film and having a cut portion at one end, and the end portion on the side opposite to the cut portion of the rectangular film is cut. A method of making a packaging bag for photosensitive material, further comprising folding back so as to be located on the inner side of the portion to form a bent portion, and then melting and bonding the outer film and the inner film on both sides.