JPH0797205B2 - Packaging material for photosensitive materials - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a packaging material suitable for packaging a photosensitive material, particularly a photographic photosensitive material.

[Conventional technology]

Various types of packaging materials for photosensitive substances have been widely put into practical use, and various performances are required according to their use.

As a packaging material for a photosensitive substance that loses its quality value when exposed to light, a packaging material that completely blocks light is used. In this case, required properties include packaging material slit suitability, gas barrier property, light shielding property, moisture proof property, rigidity, physical strength (breaking strength, tear strength, impact drilling strength, gelbotest strength, wear strength, etc.) heat sealing suitability ( Heat sealing strength, cut sealing property, hot tack property, foreign substance sealing property, etc.), antistatic property, flatness, low dust generation property, slip property, film forming suitability and the like.

Conventionally, high-pressure branched low-density polyethylene (hereinafter referred to as LDPE) resin film in which carbon black is kneaded or a composite laminate film in which LDPE resin film, paper and aluminum foil are laminated has been used as a packaging material for photosensitive materials. . For example, as shown in FIG. 15, an aluminum foil 6 and a flexible sheet layer 5 are laminated with an adhesive layer 4 between the LDPE resin film layers 2a and 2a containing a light-shielding substance.

In addition, as a packaging material for roll-shaped photographic light-sensitive materials and heavy sheet-shaped light-sensitive materials of 1 kg or more (especially sealed light-shielding bags), cross-lamination using uniaxially stretched high-density polyethylene (hereinafter referred to as HDPE) resin film with high physical strength. The present inventor has already proposed a laminated film in which an LDPE resin film containing at least one of a light-shielding substance and an antistatic agent is laminated on the film (Japanese Utility Model Publication No. 56-19087). Furthermore, a packaging material having an inexpensive cross-laminated film with improved heat-sealing property and light-shielding property was also proposed (Japanese Utility Model Publication No. Sho 61-20590).

Furthermore, as a packaging material having high physical strength, excellent heat sealing suitability, and low cost, a film layer made of a resin composition in which carbon black is added to a linear low-density polyethylene (hereinafter referred to as L-LDPE) resin is used. A packaging material made of a laminated film was proposed (Japanese Patent Laid-Open No. 61-189936).
(Japanese Patent Laid-Open No. 62-18547).

Furthermore, as a packaging material using a metal vapor deposition film, 50% by weight or more of L-LD is provided on both sides of the metal vapor deposition film layer.
A packaging material for a light-sensitive material was proposed in which an L-LDPE resin-based polymer layer containing a PE resin and 0.3 to 30% by weight of a light-shielding substance was laminated on one side or both sides (JP-A-61-54934).

Also, as a transparent bag for lightweight food and clothing, tensile strength,
A transparent film made of a crystalline polypropylene resin is widely used because it has high physical strength such as rigidity and surface hardness and excellent optical properties such as gloss and transparency.

Since this transparent film has a high heat sealable temperature and a narrow applicable temperature range, attempts have been made to improve the heat sealability by adding an ethylene / polypropylene copolymer resin or the like.

[Problems to be solved by the invention]

The laminated film having the conventional LDPE resin film,
Despite its large thickness, it has a low physical strength (tear strength, etc.), is expensive, has poor suitability for heat sealing, and has holes and tears during packaging and transportation, and peels off the heat seal to block light. It was difficult to secure the moisture resistance, moisture resistance and gas barrier property.

The packaging material having the cross-laminated film proposed in Japanese Utility Model Publication No. 56-19087 and Japanese Utility Model Publication No. 61-20590 is significantly improved in physical strength such as tear strength and tensile strength. It was excellent and was put into practical use until recently. However, since the uniaxially stretched high-density polyethylene resin film is used for the heat-sealing layer, the heat-sealing suitability is poor, and the physical strength is deteriorated due to variations in the thickness of the adhesive layer and the stretching ratio of the uniaxially-stretched high-density polyethylene resin film, resulting in a large curl. Occasionally, it sometimes peeled off or was torn.

Further, the cross-laminated film obtained by laminating the vertically uniaxially stretched film and the horizontally uniaxially stretched film so that the stretching axes intersect each other is an expensive laminated film because two types of film forming machines are used.

A packaging material having a light-shielding film using a resin composition obtained by adding carbon black to L-LDPE resin proposed in JP-A-61-189936 and JP-A-62-18547 is inexpensive and suitable for heat sealing. It is also excellent in tear strength and impact punching strength, and is very excellent as a packaging material for photosensitive materials. However, when packaging heavy products or photosensitive materials with sharp edges, the Young's modulus is small, so L-LD
The PE resin light-shielding film did not have holes or tears, but it sometimes stretched and became thin, and it was not possible to secure sufficient light-shielding and moisture-proof properties.

Although the packaging material proposed in JP-A-61-54934 has improved physical strength such as tear strength, it is a packaging in which an L-LDPE resin-based film layer containing a light-shielding substance is laminated only on one side of a metal vapor deposition film. The material was such that the curling was large.

For this reason, it has been put to practical use as a laminated film laminated with an aluminum vacuum-deposited nylon film or polyester film having a large Young's modulus and heat resistance, but these nylon films and the like are expensive because they are very easily curled.

A transparent film made by adding ethylene / propylene copolymer resin to crystalline polypropylene (hereinafter referred to as PP) resin improves the heat sealability to some extent, but has poor surface slippage and is a light-shielding substance such as carbon black. The light-shielding film added with was inferior in physical strength, heat sealability and the like and could not be put to practical use as a packaging material for a photosensitive material.

Further, the L-LDPE resin film is excellent in tear strength, impact perforation strength, heat sealability, etc., but the crystallization rate is slow, so that the bubble becomes unstable and wrinkles and blocking are likely to occur. The PP resin film had low tear strength, poor heat sealability, slow crystallization rate, and poor film formability.

The present invention solves the above problems, physical strength (tensile strength, burst strength, etc.) is large, crystallization rate is fast, cooling efficiency is good, blocking is unlikely to occur, film formability is good, and film surface It is an object of the present invention to provide a packaging material for a photosensitive substance which causes less rough skin.

[Means for solving problems]

The present invention has been made to achieve the above object,
It is a crystalline PP resin and L-LDPE resin to which a predetermined amount of a predetermined additive is added.

That is, the packaging material for a photosensitive material of the present invention comprises 5 to 40% by weight of a crystalline polypropylene resin, 30% by weight or more of a linear low-density polyethylene resin, and 0.1 to 30% by weight of a light-shielding substance.
And 0.01 to 1.0% by weight of antioxidant, 0.01 to 1.0% of organic nucleating agent
A linear low-density polyethylene resin light-shielding film layer containing 3.00% by weight and 0.01 to 6.00% by weight of a lubricant is provided.

The crystalline PP resin is a propylene homopolymer, a random copolymer of propylene and α-olefin, or a block copolymer, and is contained in an amount of 5 to 40% by weight.

If it is less than 5% by weight, the effects of improving rigidity, Young's modulus, tensile strength, and burst strength are insufficient, and if it exceeds 40% by weight, tear strength, impact puncture strength, gelbotest strength, etc. are reduced, and elongation is lost, resulting in physical deterioration at low temperatures. Practicality is lost because the strength is greatly reduced and the film moldability is also deteriorated.

The L-LDPE resin is called a third polyethylene resin, and is a low cost, high strength resin that meets the demands of the age of energy saving and resource saving, which has the advantages of both the medium and low pressure method polyethylene resin. Most of these resins are low-pressure processes and have ethylene and 3 to 13 carbon atoms, preferably 4 to 8 α-
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%.

As the α-olefin, butene-1, octene-1, hexene-1, 4-methylpentene-1, heptene-1,
Octene-1 etc. is used, and the amount is 0.5 of the polymer.
It is about 15 mol%. The density is generally considered to be about low-medium pressure polyethylene, but many 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 (UC
C Company), Dow Rex (Dow Chemical Company), Sclear (DuPont Canada Company), Marrex (Phips Company), Neo-Zex and Ulto-Zex (Mitsui Petrochemical), Nisseki Linilex (Nippon Petrochemical), Stamirex (DSM Company) ), Etc.

Among these L-LDPE resins, the ethylene content of 90 to 9 is particularly preferable from the viewpoint of physical strength and heat seal strength.
9.5 mol%, α-olefin content 0.5 to 10 mol%, melt index (hereinafter MI) 0.8 to 30 g / 10 minutes (J
ISK 6760), density 0.870-0.940g / cm ³ (JISK 6760),
And, it was obtained by a liquid phase process having 6 to 8 carbon atoms of α-olefin.

A particularly preferred representative example is the trade name of Wurtzex of Mitsui Petrochemical Co., Ltd. in which 4-methylpentene-1 having 6 carbon atoms as an α-olefin side chain is introduced into polyethylene, and α-olefin side. There are DSM's Stamilex and Dow Chemical's Dourex, etc. in which octene-1 having 8 carbon atoms is introduced as a chain (the above are L-LDPE resins obtained by the common liquid phase process of the three companies).

This L-LDPE resin is contained in an amount of 30% by weight or more. This is because if the L-LDPE resin content is less than 30% by weight, the physical strength, heat sealability and light shielding properties cannot be sufficiently secured.

The light-shielding substance refers to a substance that can be kneaded or dispersed in each layer and that does not transmit visible light, ultraviolet light, and 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 pigment, sulfur, rouge, cobalt blue, copper phthalocyanine pigment,
Examples thereof include monoazo or polyazo pigments, organic pigments such as aniline black, and inorganic pigments.

And, this light-shielding substance is contained in an amount of 0.1 to 30% by weight. 0.1
If the content is less than wt%, 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 30% by weight, the physical strength of the polyethylene resin film is lowered and the heat-sealing property is deteriorated, which makes practical application difficult.

Further, the photosensitive substance is contaminated by the light-shielding substance on the surface of the film, or the light-shielding substance is often detached from the film and adhered to the photosensitive substance, which is difficult to put into practical use.

It is also preferable to mix two or more light-shielding substances according to the required characteristics. For example, it is a mixture of a thin plate-shaped light-shielding substance and a granular or spherical light-shielding substance. In this case, the to the average particle diameter include unit area (m ²⁾ per 0.5g / m ² ~50g / m ² of packaging material the following carbon black 200mμ to ensure the light shielding property is preferable. On the other hand, among these carbon blacks, pH 5-9, average particle size 10-120
mμ is preferred, especially pH 6-9, average particle size 50m
Forness carbon black of μ 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 improvement in physical strength that is unlikely to occur and improvement in heat sealability.

Although there are various forms in which the light-shielding substance is mixed, 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 substance 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 that when an aluminum powder is produced by a known method such as a ball mill method, a stamp mill method, or an atomizing method, the presence of a solvent such as mineral spirit and a small amount of a higher fatty acid such as stearic acid or oleic acid. It was made in paste form. 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 solvents such as mineral spirits with a strong malodor) are removed with a vacuum pump etc. and used as aluminum paste compound resin and aluminum paste masterbatch resin. To do.

In particular, it is preferable to use it as 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 a master batch resin having an aluminum paste content of 40% by weight is 1.0% by weight, if the aluminum paste concentration in the film layer is set to 2% by weight, the aluminum paste masterbatch 1 Since 19 parts by weight of natural resin is to be kneaded with respect to parts by weight, there is a portion of the film layer where mineral spirits are removed as a gas during film forming, so there is also a portion where mineral spirits are removed as a gas. Mineral spirit content is less than 0.05% by weight. 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. Since the aluminum powder alone is unstable, various known treatments for inactivating the surface of the aluminum powder are performed. The most typical treatment is a method of forming a higher fatty acid metal salt on the surface of aluminum powder with a saturated or unsaturated higher fatty acid.

The following are typical examples of the antioxidant.

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'-thiobis (3-methyl 6-t-butylphenol, 4,4'-butylidene bis (3-methyl-6-t-butylphenol), stearyl-β (3,5-di-4-butyl 4-hydroxy) Phenyl) 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, octadecyl-3- (3,5-di) -T-butyl-4-hydroxyphenyl) propionate, tetrakis [methylene-3 (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, etc. Sulfur-based dilauryl-3,3'-thio Dipropionate, dimyristyl-3,3′-thiodipropionate, lauryl stearyl thiodipropionate, distearyl-3′-thiodipropionate, ditridecyl-3,3′-thiodipropionate Phosphorus trinonyl Phenyl phosphite, triphenyl phosphite, etc. Amine type phenyl-β-naphthylamine, N, N′-di-β-naphthyl-p-phenylenediamine, N, N'-diphenyl-phenylenediamine, phenyl-α-naphthylamine, phenyl-β-naphthylamine, etc.Thioether-based di-lauryl-thio-di-propionate, di-stearyl-thio-di-propionate, etc. -T-butyl-p-cresol (BHT) and low volatility high molecular weight phenolic antioxidant (trade name: lreg
anox 1010, lreganox 330, Topano ICA etc.), dilauryl thiodipropionate, distearyl thiodipropionate, dialkis phosphate, etc., especially 2
It is effective to use two or more together.

The addition amount is 0.01 to 1.0% by weight both in the case of using alone and in the case of using two or more kinds in combination. 0.01% by weight
If it is less than the above, there is almost no effect of addition. On the other hand, the addition amount is 1.0
There is a case where the photographic film utilizing the oxidation and reduction action exceeding the weight% is adversely affected and the performance is abnormal. For this reason, it is preferable to add the antioxidant in the minimum amount that does not cause coloring failure or spots. Particularly preferred are phenolic antioxidants, and commercially available products include various Irganox from Ciba Geigy and Sumili from Sumitomo Chemical Co., Ltd.
zer BHT, Sumilizer BP-76, Sumilizer WX−R, Sumilizer
There is BP-101 etc.

The organic nucleating agent is preferably a dibenzylidene sorbitol compound, for example, bis (methylbenzylidene) sorbitol, 1,3,2,4-di- (methylbenzylidene) sorbitol, 1,3,2,4-di (toluylidene) sorbitol, 1,3,2,4-di (alkylbenzylidene) sorbitol, 1,3,2,4-di (para-ethylbenzylidene) sorbitol, 1,3,2,4-di (paramethoxybenzylidene) sorbitol, 1, Typical examples include 3,2,4-di (paraethoxybenzylidene) sorbitol, high-purity alkyl-substituted dibenzylidene sorbitol (Nippon Rika Gelol MD), sodium benzoate, etc.
Contains 3.00% by weight.

If it is less than 0.01% by weight, there is almost no addition effect, and if it exceeds 3.00% by weight, the bad odor becomes strong and the effect of increasing the amount cannot be expected 3.
The effect is almost the same as that of 00% by weight, which is meaningless.

As the benzylidene sorbitol compound organic nucleating agent or the bis (substituted benzylidene) sorbitol compound organic nucleating agent effective in the present invention, for example, those described below can be used.

Alkyl group: Methyl group, ethyl group, propyl group, isopropyl group, butyl group, etc. Alkoxy group: Methoxy group, ethoxy group, propoxy group, ptooxy group, etc. or a derivative nuclear-substituted with halogen such as chlorine. The agent is preferably surface-treated with a stabilizer such as an aliphatic metal salt, an alkyl lactic acid metal salt or a lactic acid metal salt in order to prevent the malodor of the molding resin and improve the dispersibility.

Examples of the lubricant include saturated fatty acid amide type, unsaturated fatty acid amide type, bis fatty acid amide type, higher fatty acid type, fatty acid metal salt type, metal sulphosuccinate type and silicon type.

The representative lubricants and their manufacturer names are listed below.

(1) Silicone lubricants; various grades of dimethylpolysiloxane (Shin-Etsu Silicone, Toray Silicone), etc. (2) Oleic acid amide lubricants: Armoslip CP (Lion Akzo), Neutron (Nippon Seika), Neutron E- 18 (Nippon Seika), Amide O (Nitto Kagaku), Alflo E-10 (Nippon Yushi), Diamid O-200 (Nippon Kasei), Diamid G-200 (Nippon Kasei), etc. (3) Erucamide amide series Lubricants: Alflo-P-10 (Nippon Yushi), Neutron S (Nippon Seika), etc. (4) Stearic acid amide lubricants: Alflo-S-10
(Nippon Yushi), Neutron 2 (Nippon Seika), Diamid 200 (Nippon Kasei), etc. (5) Bis fatty acid amide lubricants; Bisamide (Nippon Kasei), Diamid 200 bis (Nippon Kasei), Armowax EBS ( (Lion Akzo) etc. (6) Alkylamine lubricants; Electrostriper-TS-2 (Kao Soap) etc. are available.

The amount of such a lubricant added is 0.01 to 6.0% by weight.
If it is less than 0.01, there is almost no effect of improving the characteristics such as fluidity, and only the kneading cost increases. If it exceeds 6.0% by weight, slippage with the screw of the extruder is increased and it becomes difficult to form a film having a uniform thickness.
Further, bleed-out easily occurs, and when it is used for a photographic light-sensitive material, it adheres to the light-sensitive layer and causes troubles such as development inhibition. It is preferably 0.05 to 1.0% by weight.

Further, the lubricant can be added not only by itself but also in combination of two kinds within the above range. The preferred fatty acid amide lubricant has 8 to 50 carbon atoms, and 15 is particularly preferred.
~ 35.

The L-LDPE resin light-shielding film layer is formed with the above composition. The packaging material for the photosensitive material of the present invention is L
-Either a single layer of the LDPE resin-based film layer or a multilayer co-extruded film layer of the L-LDPE resin-based film layer and other layers, other layers are directly or adhered to the L-LDPE resin-based film layer. It may be a layer indirectly laminated through a layer.

The packaging material for a photosensitive substance of the present invention can be used for packaging any photosensitive substance such as a photographic photosensitive material, food, medicine, chemical substance and the like. In particular, silver halide photographic light-sensitive materials, heat-developable light-sensitive materials, diazo photographic light-sensitive materials, direct positive color light-sensitive materials, photosensitive resins, self-developing photographic light-sensitive materials, diffusion transfer, whose quality is destroyed by slight gas, light and humidity. It is most suitable for photographic light-sensitive materials such as mold photographic light-sensitive materials.

When the packaging material for a photosensitive material of the present invention is applied to the above photographic photosensitive material, for example, a single flat bag, a double flat bag, a self-supporting bag, a single gusset bag, a double gusset bag, a single layer L-LDPE resin film, It can be used in all known forms such as multi-layer co-extrusion L-LDPE resin film, multi-layer co-extrusion L-LDPE resin film, moisture-proof box inner sticking, bright room loading light-shielding box inner sticking, and leader paper.

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

[Action]

In the packaging material for a photosensitive material of the present invention, the crystalline PP resin has a synergistic effect with an organic nucleating agent and a light-shielding material, L-LDPE resin,
Due to the combined effect with a lubricant, light-shielding property, Young's modulus, tensile strength,
The burst strength and rigidity are greatly improved, the crystallization speed of the film is increased, the bubbles are stabilized, the film forming speed is improved, cooling is less likely to occur, blocking is less likely to occur, and the slip property is further improved. Is improving. L
-LDPE resin improves heat sealability, tear strength, impact puncture strength, etc., which are lacking in PP resin, and when used in combination with a light-shielding material, the strength of these materials is synergistically improved. In addition, by using in combination with PP resin, haze is increased to improve light-shielding properties, and in combination with a light-shielding substance such as carbon black, the synergistic effect improves physical strength, heat-sealing properties, and antioxidation effects. There is. Even if the antioxidant is heated to a temperature at which the PP resin having a higher melting point than the L-LDPE resin is completely melted, the L-LDPE resin is prevented from being burnt or colored. The organic nucleating agent exerts a synergistic effect such as improvement of tensile strength, Young's modulus, rigidity, burst strength and improvement of film moldability when used in combination with PP resin, and also prevents roughening of the film surface due to the effect of combined use with a lubricant. ing. The lubricant improves the dispersibility of the light-shielding substance, improves the film formability, prevents the film from wrinkling, improves the packaging processability, improves the smoothness of the film surface, improves the lubricity, and prevents dust. In addition, the peeling charge amount is reduced.

〔Example〕

Embodiments of the packaging material for a photosensitive material according to the present invention are shown in FIGS.
It will be described with reference to the drawings.

1 to 13 are partial cross-sectional views showing the layer structure of the packaging material for photosensitive substances.

The packaging material for the photosensitive material shown in FIG. 1 is composed of a single film of the L-LDPE resin film layer 1a.

The packaging material for a photosensitive substance shown in FIG. 2 is composed of a multilayer co-extruded light-shielding film 1a composed of two layers, an L-LDPE resin film layer 1a and a thermoplastic resin film layer 2a containing a light-shielding substance.

The packaging material for a photosensitive substance shown in FIG. 3 is composed of a multilayer co-extruded light-shielding film 1a composed of two layers, an L-LDPE resin film layer 1a and a thermoplastic resin film layer 2 containing no light-shielding substance.

The packaging material for the photosensitive material of FIG. 4 is composed of a multi-layered coextruded light-shielding film 1a consisting of three layers in which an intermediate layer 3 is laminated between two L-LDPE resin film layers 1a.

The packaging material for the photosensitive material shown in FIG. 5 is an L-LDPE resin film layer 1a and a thermoplastic resin film layer 2a containing a light shielding material.
It is composed of a multi-layer coextruded light-shielding film 1a consisting of three layers in which an intermediate layer 3 containing no light-shielding substance is laminated between them.

The packaging material for the photosensitive material shown in FIG. 6 is an L-LDPE resin film layer 1a and a thermoplastic resin film layer 2a containing a light shielding material.
It is composed of a multi-layer coextruded light-shielding film 1a consisting of three layers in which an intermediate layer 3a containing a light-shielding substance is laminated in between.

The packaging material for the photosensitive material of FIG. 7 is composed of three layers in which an intermediate layer 3a containing a light-shielding substance is laminated between an L-LDPE resin film layer 1a and a thermoplastic resin film layer 2 containing no light-shielding substance. The multi-layer coextrusion light-shielding film 1a.

The photosensitive material packaging material of FIG. 8 is composed of three layers in which a flexible sheet layer 5 is laminated on an L-LDPE resin film layer 1a with an adhesive layer 4 interposed therebetween.

The packaging material for the photosensitive material of FIG. 9 is constituted by directly laminating the heat seal layer 7 on the L-LDPE resin film layer 1a.

The packaging material for the photosensitive material shown in FIG. 10 is formed by laminating the flexible sheet layer 5 on the multilayer coextrusion light-shielding film 1a shown in FIG. 2 via the adhesive layer 4.

The packaging material for the photosensitive material shown in FIG. 11 is formed by laminating the metal foil 6 and the flexible sheet layer 5 on the multilayer coextrusion light-shielding film 1a shown in FIG.

The photosensitive material packaging material of FIG. 12 is formed by laminating a metal thin film processed flexible sheet layer 9 obtained by processing a metal thin film 8 on a flexible sheet layer 5 between the multilayer coextrusion light shielding films 1a shown in FIG. There is.

The packaging material for photosensitive material of FIG. 13 is configured by laminating a metal foil 6 between two L-LDPE resin film layers 1a with an adhesive layer 4 interposed therebetween.

FIG. 14 is a partial cross-sectional view showing the layer structure of the comparative example, which is composed of a single film of the thermoplastic resin film layer 2a containing a light-shielding substance.

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

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

Crystalline polypropylene resin 20.0 wt% Propylene-ethylene random copolymer resin by vapor phase polymerization method of 97 wt% propylene and 3 wt% ethylene MI 40 g / 10 min Density 0.910 g / cm ³ L-LDPE resin 76.6 wt% Ethylene And 4-methylpentene-1 copolymer resin MI 2.1g / 10min Density 0.920g / cm ³ Phenolic antioxidant (BHT) 0.2wt% Lubricant 0.1wt% Oleic amide Organic nucleating agent 0.1wt% 1. 3,2,4-Bis (methylbenzylidene) sorbitol Light-shielding substance 3.0% by weight Oil fornes carbon black The above resin composition was used to form a blow-up ratio of 2 and a thickness of 70 μm using an inflation film molding machine.

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

L-LDPE resin light-shielding film layer The same resin composition as the product I of the present invention was formed to a thickness of 30 μm.

Thermoplastic resin light-shielding film layer Instead of crystalline polypropylene resin, the following L-LDPE
The resin composition is the same as the product I of the present invention except that a resin is used.

L-LDPE resin Copolymer resin of ethylene and butene-1 MI 2.0 g / 10 min Density 0.922 g / cm ^{3 The} above two layers were coextruded into two layers and molded to a thickness of 70 μm using an inflation film molding machine.

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

Flexible sheet layer Aluminum vacuum vapor-deposited biaxially stretched nylon film with a thickness of 15 μm Metal thin film Metal thin film is an aluminum vacuum vapor-deposited film with a thickness of 400 Å Adhesive layer LDPE resin extrusion adhesive layer MI 5.1g / 10 minutes Density 0.919g ・ cm ³ Thickness The 15 μm L-LDPE resin light-shielding film layer and the thermoplastic resin film layer are the same as those of the present invention product II.

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

Crystalline polypropylene resin 20.0% by weight Same as product I of the present invention L-LDPE resin 76.6% by weight Same as product I of the present invention Light-shielding substance 3.0% by weight Oil fornes carbon black Blow using the inflation film molding machine with the above resin composition. It was formed to a thickness of 70 μm with an up ratio of 2.

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

L-LDPE resin 96.8% by weight Same as product I of the present invention 0.2% by weight of phenolic antioxidant (BHT) 3.0% by weight of light-shielding substance Oil forness carbon black Conventional product I Conventional product I has the layer structure shown in FIG. Equivalent to.

LDPE resin 96.8% by weight MI 2.3g / 10min Density 0.923g / cm ³ Phenolic antioxidant (BHT) 0.2% by weight Light-shielding substance 3.0% by weight Oil fornes carbon black With the above resin composition, using an inflation molding machine The blow ratio was 2 and the thickness was 70 μm.

The experimental results are shown in Table 1.

The evaluation is as follows.

◎… very good ○… excellent ●… possible (within practical limits) ▲… problem, need improvement ×… not practical * A bubble stability When a film was formed on an inflation film molding machine under the above conditions Judgment based on valve fluctuation, meandering, change in folding diameter, etc. * B Surface roughness prevention sensory evaluation of melt fracture occurrence and film surface condition when a film is formed under the above conditions with an inflation film molding machine * C Tear strength Compliant with JISP8116 * D Tensile strength Compliant with JISP8133 * E Young's modulus (= longitudinal elastic modulus kg / mm ² ) Using a Toyo Seiki tensile tester (trade name Strograph)
Measured at 20 ° C and 65% RH according to the method according to ASTM D-882 * F blocking After forming with an inflation film molding machine, sensory evaluation of blocking strength inside the inflation film * G film molding The resin prescription of each sample using a single-layer or simultaneous two-layer coextrusion blower film molding machine, the small current load when forming a film with the film thickness, the stability of bubbles, and the occurrence of film wrinkles. Judgment based on smallness, etc. * H Molding machine passability Appropriate observation of the passability of the guide plate and pass rolls of the molding machine and the occurrence of wrinkles when forming a film with an inflation film molding machine [Effect of the invention] The present invention is configured as described above. Therefore, the fluidity of the resin, the stability of bubbles, and the antistatic property are improved by the lubricant and the light-shielding substance. The occurrence of streaks of pinholes is prevented reduce skin irritation caused by eye boogers and stones by the use effect. Further, due to the combined effect of the crystalline polypropylene resin and the organic nucleating agent, even if the crystallization is promoted to increase the film forming speed, even if the cooling is insufficient, there is slipping and blocking does not occur, and rigidity, The Young's modulus, tensile strength and tear strength are improved. Further, the combined use of the L-LDPE resin and the light-shielding substance improves the tear strength, impact drilling strength, elongation, gelbotest strength and the like.

[Brief description of drawings]

1 to 13 are partial cross-sectional views showing a layer structure of a packaging material for a photosensitive material of the present invention, FIG. 14 is a partial cross-sectional view showing a layer structure of a comparative example, and FIG. 15 is a layer structure of a conventional example. FIG. 1a L-LDPE resin film layer 1a 2, 2a Thermoplastic resin film layer 3, 3a Intermediate layer 4, 4a Adhesive layer 5, 5a Flexible sheet layer Ia Multilayer coextrusion resin Film a; indicates that it contains light-shielding substances

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03C 3/00 F J Z 565 A

Claims (1)

[Claims] 1. Crystalline polypropylene resin 5 to 40% by weight
30% by weight or more of linear low-density polyethylene resin, 0.1-30% by weight of light-shielding substance, and 0.01-1.0% by weight of antioxidant
And a linear low density polyethylene resin light-shielding film layer containing 0.01 to 3.00% by weight of an organic nucleating agent and 0.01 to 6.00% by weight of a lubricant.