JPS6253829A - Double bag for photosensitive material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a double bag for photographic materials having high physical strength, moisture proofing and light blocking properties.

[Conventional technology]

Various types of double bags for photographic materials have been widely put into practical use, and various performances are required depending on the purpose of use.

Packaging materials that completely block light are used as double bags for photographic materials that lose their quality value when exposed to light.

In this case, the required properties include packaging material slit suitability, spalling properties, light shielding properties, moisture proofing properties, rigidity, and physical strength (
Breaking strength, tear strength, impact drilling strength, ruda test strength, abrasion strength, etc.) heat sealability (heat seal strength, hot tack property, contaminant sealing property, etc.), antistatic property,
Examples include flatness, anti-blocking properties, and sliding properties. It is difficult to have both of these properties in a single film as shown in Figure 15, and conventionally, high-pressure branched low-density polyethylene (hereinafter referred to as Lm) mixed with Cargin black, pigments, etc. has been used. Composite laminate films of an LDPg film layer made of resin (indicated by PE) and a flexible sheet layer of paper, aluminum foil, cellophane, etc. have been used.

Conventionally, such composite laminate films include those shown in FIGS. 16 to 20. 16th
In the figure, an aluminum foil layer 11 is laminated on an LDPE light-shielding film layer 10 via an adhesive layer 2, and a flexible sheet layer 4 is further laminated via an adhesive layer 2. 1st
FIG. 7 shows an LD layer further placed on the flexible sheet layer 4 of the composite laminate film shown in FIG. 16 via an adhesive layer 2.
A PE light-shielding film layer 10 is laminated. 18th
In the figure, L-LDPE light-shielding film layers 1a are laminated on both sides of an aluminum foil layer 11 via an adhesive layer 2. FIG. 19 shows the composite laminate film shown in FIG. 16 in which the LDPE light-shielding film layer 10 is changed to an L-LDPE light-shielding film layer 1a.

In addition, the present inventor has developed a film with improved physical strength by combining two layers of uniaxially stretched films (Japanese Unexamined Patent Publication No.
7-6754) has already disclosed, for example, the one shown in FIG. The composite laminate film shown in FIG. 20 has uniaxial molecularly oriented light-shielding film layers 12 on both sides of an aluminum foil layer 11 so that molecular alignment axes intersect.
are laminated with an adhesive layer 2 interposed therebetween.

In addition, even in packaging materials using L-LDPK resin, more than 50% by weight of the total ethylene polymer is due to the light-shielding property of more than 1 weight of ethylene polymer and L-LDPK resin.
-LDPlil: A device having at least one light-shielding film made of resin has already been disclosed, for example, as shown in FIG.

[Problem that the invention seeks to solve]

Conventional composite laminate films are constructed to improve the physical properties mentioned above, but the physical properties are still not sufficient, resulting in tears and holes during packaging, and the heat-sealed part peels off. There were drawbacks such as.

In addition, adding a large amount of light-shielding properties such as Cargen Black will significantly reduce the physical strength, so the amount added is around 3%,
The thickness of the film laminated with the flexible sheet layer of the pond had to be 70 μm or more. As a result, the packaging becomes bulky and the rigidity of the composite laminate film increases, resulting in poor packaging workability and increased costs.

For example, in the laminated films shown in Figures 16 and 17, the aluminum foil layer is used to provide sparring properties, improve moisture resistance, and prevent static electricity. Strength, r? On the contrary, the test strength deteriorated to a large extent, leading to problems of breakage, especially when packaging heavy items.

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, not only does the tear strength decrease. -Since an axially stretched high-density polyethylene film layer is used, heat sealability is poor, which sometimes causes problems during processing and packaging. In addition, when using a cross-laminated film in which the axially stretched film layers are laminated crosswise without using aluminum foil, pinholes occur in the gusset of the set bag when the product is packaged in a jet bag, making it difficult to use for photographic materials. As a packaging material, it could not be put to practical use due to its poor light-shielding and moisture-proofing properties.

By using L-LDPg resin as a packaging material, physical strengths such as tear strength and Rude test strength can be increased, and the amount of light-shielding substance kneaded can be increased, and the above-mentioned problems can be improved. However, if the film thickness is reduced, wrinkles and film folding will occur, resulting in insufficient tensile strength, sliding properties, rigidity, moisture resistance, and manufacturing suitability. and film slitting properties deteriorate. - Also, when a photographic material with sharp edges is packaged with only a single film layer, the bag may tear due to vibration during transportation, or black pine may adhere to the surface of the photographic material due to wear of the light-shielding film hj, causing malfunctions. There were many things.

Further, when L-LDPK light-shielding film layers as shown in FIG. 18 are laminated on both sides of an aluminum foil layer, there is a problem that not only is the price high, but also the tear strength and impact puncture strength are significantly reduced.

Furthermore, in order to make a double bag consisting of an inner paper and an outer paper, the inner paper and the outer paper are bonded at predetermined points using heat sealing or the like, but the two sides are different as shown in Figure 19. In this case, if the inner paper was fed with the wrong front and back sides due to the feeding mechanism of the machine, the bag could not be made due to the difference in heat sealing temperature and the difference in slipperiness and curling.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a double bag for photographic materials that has improved product insertability, slit suitability, physical strength, heat seal suitability, etc.

[Means for solving problems]

The present invention was made to achieve the above object, and consists of a linear low-density polyethylene (hereinafter referred to as L-LDPE) resin made of ethylene and an α-olefin having 3 to 13 carbon atoms, and a metal powder or carbon. L-LD containing black, lubricant, and anti-blocking agent and having a thickness of 40 to 150 μm
An inner paper on which a PE light-shielding film layer is located on both sides, and a surface provided on the outside of the inner paper and in contact with the inner paper has a thickness of 10 to 12
JIS Z 02 for a combination of the inner paper and the outer paper, which has an outer paper containing a thermoplastic resin film layer of 0 μm.
The present invention is a double bag for photographic materials characterized by a moisture permeability of 59/m224h or less according to the No. 22 test method.

The L-LDPE fallen fat, which is the first composition essential for the inner paper of the present invention, is a conventional high-pressure branched low-density polyethylene (hereinafter L-LDPE fallen fat).
(Denoted as DPE) Compared to resins, it has a narrow molecular weight distribution, is linear, has strong physical strength, has good hot tack properties and impurity sealing properties, has strong heat sealing strength, and has good cold resistance. . L- with a density of around 0.920 g/cm5
LDPE resin film has little directionality and high tear strength and impact puncture strength, but low tensile strength and stiffness, poor moisture resistance, and is prone to blocking. Density is 0.93
0 g/cm' or more L-Ll) Pg resin film is
This property is contradictory to that of the L-LDPg resin film, which has a density of around 0.920 g/m'. Therefore, in the present invention, L-
LDPE resin has furnace carton black, anti-blocking agent, and lubricant added, so there is no blocking, and it has excellent tear strength, impact hole-proofing strength, and heat-sealing properties. Even with a single resin film layer, it has high rigidity, tensile strength, A film layer with good antistatic properties, lubricity, etc. is used. The outer paper can be heat-sealed with the inner paper, and preferably has a film layer that has better heat resistance and moisture resistance than the inner paper, such as a blend of high-density polyethylene resin, polyethylene resin, or L-LDpgm resin with a heat-resistant resin or pigment. The present invention provides a moisture-proof and light-shielding bag for photographic materials which is made by partially bonding with paper and has excellent characteristics.

Here L-I, DPE m fat is ethylene and carbon number 3~
13 pieces, preferably 4 to 10 pieces, particularly preferably 6 pieces
It is a copolymer made by copolymerizing ~8 α-olefins.

Examples of the polymerization process include a medium-low pressure gas phase process, a liquid phase process, and a high pressure ionic polymerization process.

The L-LDPE resin used in the present invention is preferably a low-pressure gas phase process product or a liquid phase process product from the viewpoint of required properties and cost.

Specific examples of product names include Unipol (UCC), Dowlex (Dow Chemical), Sflair (DuPont Canada), Marlex (Philigs), Neozex and Ultzex (5 Well Petrochemicals), and Shiraishi Linirex ( Nippon Petrochemical), Stamilex (DSM)
, NUC Polyethylene-LL and TUFLIN (Nippon Unicar).

α-olefins include butene-1, octene-1, hexene-1,4-methylpentene-1, hegetene-1,
etc. are used, the amount being from 0.5 to 15 moles of polymer. The density is generally considered to be low to medium density, but many commercially available products are within the range of 0.87 to 0.959/cm'.

Among these L-LDPE resins, ethylene fjl is particularly preferable in terms of moisture resistance, stiffness, slit note, heat cut sealability, physical strength, heat seal strength, etc.
t9o~99.5 molti, alpha olefin content is 0.5
~10 molti, melt index (hereinafter referred to as MI)
is 0.8~10 fil/10 ba ASTM D-1238
). Density is 0.918~0.94052/m' (AST
MD-1505).

It is an L-LDPE resin produced by a low-pressure liquid phase process or a gas phase process in which the alpha olefin has 6 to 8 carbon atoms.

The most preferred representative product name is L-LDPE, which uses 4-methylpentene-1 with 6 carbon atoms as the α-olefin side chain in low-pressure ethylene. Urtozex is available, and L-LD uses 8-carbon octene-1 as the α-olefin side chain.
Examples of PK resins include Stamilex from DSM and Dowlex from Dow Chemical. (All of the above three companies' products are L-LDPK resins produced by the low-pressure liquid phase process.) The low-pressure vapor phase process products include L-LDPK resins using hexene-1 with 6 carbon atoms as the α-olefin side chain. - As an LDPE resin, there is TUFLIN from Nippon Unicar Co., Ltd.

The metal powder and cardan black, which are the second essential components of the inner paper of the present invention, and which improve light-shielding properties, antistatic properties, anti-blocking properties, moisture-proof properties, and physical strength, will be explained.

As the metal powder, it is particularly preferable to use aluminum powder or aluminum paste from which low volatile substances have been removed and kneaded with a thermoplastic resin. What does aluminum paste mean? - When making aluminum powder by a known method such as the Lumil method, Stamp Mill method or Atomization method, the paste is prepared in the presence of mineral spirit and a small amount of higher fatty acids such as stearic acid or oleic acid. In the present invention, this aluminum paste and polyolefin thermoplastic resins (various polyzolopyrene resins, various polyethylene resins, EVA resins, IJA resins, IAA resins, etc.) are heated and kneaded to remove low volatile substances (mainly odor-free). Aluminum (-Stokon/Gland resin, Aluminum Paste Mister-Batch resin) from which strong mineral spirit) is removed with a vacuum pumper etc. is used again.

In particular, K is used as an aluminum paste master patch resin to eliminate harmful effects and bad odors on photographic materials, and to reduce the mineral spirit content in the L-LX) PE light-shielding film layer to 0.1% by weight or less. preferable. For example, if the aluminum paste content is 40, the mineral spirit content in the master patch resin is 1.
Even if it is 0 wt %, if the aluminum (-st) concentration in the L-LDPE light-shielding film layer is 2 wt % KL, then natural L-LDPE @ fat will be added to 1 part by weight of the aluminum paste master patch. Since some mineral spirit is removed as gas during film forming in the L-LDPK resin layer, the mineral spirit content is 0.05 parts by weight.
i% or less. As a result, there is no adverse effect on the photographic material, and odor is also reduced.

Aluminum powder is not only molten aluminum made into powder by the mattomization method, granulation method, rotating disk dropping method, evaporation method, etc., but also aluminum foil. -Includes those crushed into flakes by the lumill method, stamp mill method, etc. Since aluminum powder alone is unstable, various known treatments are performed to inactivate the surface of the aluminum powder.

A known method for producing metal flakes is U.S. Pat. No. 4,46
No. 9,282, Special Publication No. 37-6779, Special Publication No. 4
There is a method described in Japanese Patent Publication No. 6-6718, etc., and a method for producing metal powder for filling synthetic resin is disclosed in Japanese Patent Application Laid-Open No. 59-759.
31st grade is 6th. Carmen black can be classified according to its raw materials, such as somber black, oil furnace black, anthracene black, acetylene black, channel black, oil smoke, pine smoke, animal black, and vegetable black. For the packaging material of the present invention, furnace cargo/black is preferable for the purpose of improving light shielding properties, cost, and physical properties, while acetylene carton black and modified by-product carne black are preferable because they are expensive but have an antistatic effect. Ketchen Cargo/Black is preferred, 2 if necessary
More than one type of cargo/black or aluminum powder can also be mixed according to the required properties. On the other hand, among these cargo/blacks, those with a pH of 5 to 9 and an average particle diameter of 10 to 120 μm are preferable, with a special Kp) of 16 to 8.
, oil furnace cargo/black having an average particle diameter of 15 to 30 μm is preferred.

By using particles with a larger diameter and particle size, there is less generation of capri on the photographic light-sensitive material, less increase or decrease in photosensitivity, large light-shielding ability, and no adverse effects on the photographic light-sensitive material. Even when added to a thermoplastic resin film, it has many advantages such as being less likely to generate pinholes such as cargo/black lumps and fish eyes. Examples of methods for blending metal powder or carbon plaque into L-LDPE resin include the powder* addition method, paste addition method, moisturizing addition method, concrete base method, and master patch method. Among these, the master patch method is preferable in terms of cost, prevention of workplace contamination, and the like.

A publicly known document, Japanese Patent Publication No. 40-26196, describes a method for preparing a master patch of polymer cargo/black by dispersing cargo/black in a solution of a single polymer dissolved in an organic solvent. The publication discloses a method for preparing a master patch by dispersing cargo/black in polyethylene. In the case of the master patch method, a master patch is first prepared by mixing cargo/black with I, DPI resin, or I olefin resin at a high concentration of 2 parts or more, generally 10 parts by weight or more.

This master patch is weighed and mixed with L-LDPE resin so that the final product has a predetermined amount of cargo/black.

Two advantages can be recognized in this method.

First, it is easier to mix and disperse cargo/black than directly mixing it with the L-LDPE resin, resulting in lower costs and improved fish eyes.

Secondly, a mixed system of LDPK or I-lyolefin resin and L-LDPK resin has better processability when producing a film than L-LDPE resin alone. L-LDPE resin may be used as the master patch resin to reduce the cost of cargo/black mixing. As the master patch paste resin, any thermoplastic resin that can be mixed with the L-LDPE resin can be used, but I-lyolefin resins are particularly preferred. In particular, a thermoplastic resin having a higher melt index than the L-LDPg resin for the master patch resin is preferred. The same is true when metal powder is used.Instead of HDPK or LDPK alone, the present inventors used L-LD, which had previously been problematic as a packaging film.
A mixed resin of PK resin and LDPE resin was used to test the effect of Rikigen Black formulation. As a result, L-LDP
When cardan black is blended with E-based resin, HDP
An unexpected result was found in that the physical strength was significantly increased, contrary to the case of E alone resin or LDPE alone resin.

That is, HDPE-based resin films and LDPK-based resin films originally have lower strength than L-LDPE-based resin films, but the strength decreases particularly when cargo/black is added. On the other hand, L-LDPg
The strength of the resin film is improved by adding carbon black.

The same can be said of L-LDPE single resin films. L-LDPI single resin film and L-LDPE
The effect of cargo/black compounding on the resin film is 0.
, 1% by weight, it clearly appears at 1% by weight, and becomes noticeable when it exceeds 3% by weight, but if the amount added is further increased, the appearance of spots will increase and the cost will increase. If it exceeds 20 weight ffi%, there will be problems such as the occurrence of splats due to poor dispersion of the special 90% carbon black, more wear debris adhering to the photosensitive material due to vibration during transportation, and poor light shielding properties due to pinholes. It is. Moreover, the cost is also relatively high.

Therefore, the blending amount of cargan black should be determined based on economic efficiency, debris generation,
From tear strength etc. 011 to 20% by weight, preferably 0
．． It is 5 to 10% by weight, and 3 to 7% by weight is particularly preferable.

Typical anti-blocking agents, which are the third component essential to the inner paper of the present invention, include silica, siloid, avicel, spherical lath, and spherical inorganic pigments.

The fourth composition essential for the inner paper of the present invention is a lubricant, which not only improves suitability for processing machines and makes it easier to insert products, but also prevents static electricity from being generated during film molding and packaging of photographic materials. . Furthermore, it is added to prevent blocking of the film and to improve film formability during film forming using the T-die method, inkling method, etc.

If the amount of lubricant added is large, the above properties can be greatly improved, but the heat sealability may deteriorate, adversely affect the photographic material (inhibit development), cause it to stick, or attract dust. This may cause problems such as: Therefore, it is preferable to add 0.05 to 1.0% by weight of a lubricant. Dimethylpolysiloxane and fatty acid amide lubricants (oleic acid amide, erucic acid amide, stearic acid amide, amide, ethylamide, etc.), and fetal acid-based lubricants are particularly preferred. Particularly preferred are electrostrippers made of engineered soaps that have sliding properties and antistatic effects.

Representative examples of commercially available lubricants preferred for the present invention are described below, but the present invention is not limited thereto.

Silicone lubricant; various dimethylpolysiloxanes (Shin-Etsu Silicone, Toshi Silicone) Oleic acid amide lubricant; Armoslip CP (Lion Akzo), 2, -Tron (Nippon Fine Chemical), 2.

-Tron E18 (Nippon Fine Chemical), Amide 0 (Nitto Chemical)
, Alflo E10 (NOF).

Diamond 0-200 (Nippon Kasei), Diamond G
Erucic acid amide P-based lubricants such as -200 (Nippon Kasei); stearic acid amide-based lubricants such as Alflo p-io (Nippon Oil &Fats); Alflo S-1
0 (Nippon Oil & Fats), 2, -Tron 2 (Nippon Fine Chemical).

Diamond 200 (Nippon Kasei) etc. Bis fatty acid amide lubricant; Bisamide (Nippon Kasei).

LDPE #J resin in the L-LDPE resin film layer with Diamond 200 Bis (Nippon Kasei), Armowax-EBS (Lion Akzo) alkylamine-based lubricant; Electrostritz TS-22 (chemical soap), etc. Other resins that can be blended as needed include HDPE.
Although resins are preferably used, some polymers such as Ike's 4-lyolefin polymers, such as medium density polyethylene (hereinafter M
Displayed as DPE) Various resins? Ligropyrene resin, ethylene-vinyl acetate copolymer (hereinafter referred to as 17A) resin, ethylene-ethyl acrylate copolymer (hereinafter referred to as EEA) resin, ethylene-methacrylate copolymer (hereinafter referred to as E
Displayed as MA) Resin, Bori-in Petile/Resin, Ethylene-
It is also possible to blend acrylic acid copolymer (hereinafter referred to as BAA) resin, etc., as long as the basic properties are not changed.

In the inner paper of the present invention, various additives other than the above-mentioned essential additives can be added in required amounts as necessary.

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

(Additive type) (Representative example) (1) Possible ff
I agent: phthalate ester, glycol ester, fatty acid ester, phosphate ester, etc. (2) Stabilizer: Lead-based, cadmium-based, zinc-based, alkaline earth metal-based, organic tin-based, etc. (3) Antistatic agent: positive Ionic activator, anion activator.

Nonionic activator 1 Bifacet activator 1 etc. (4) Fuel agent: F [ester, halodanization m Redemption: r
- Stell.

Halocide, inorganic substance, phosphorus-containing polyol, etc. (5) Filler; alumina, kaolin, clay, calcium carbonate, mica, talc, titanium e12, silica (6) Reinforcing agent:
(7) Colorant: Inorganic pigment (At, Fe2O, 5T10)
3. Zn0tCdS etc.).

Organic pigment dye 1st class (8) Blowing agent; inorganic blowing agent (ammonia carbonate, sodium bicarbonate) organic blowing agent (thoron type, ano type) 2nd class (9) vulcanizing agent; vulcanization accelerator, accelerating aid, etc. α0 deterioration Inhibitors: ultraviolet absorbers, antioxidants, metal deactivators, peroxide decomposers, etc. α and coupling agents: silane, titanate, chromium, aluminum, etc. (6) Various thermoplastic resins, A double bag is formed by partially adhering an outer paper to the outside of an inner paper such as -f grade 5 or above. This is an essential composition of outer paper. Various thermoplastic resins can be used as the thermoplastic resin, but when used in a resin-only film, polyolefin resins, especially L-LD with a density of 0.93077/cm" or higher, are used.
PE resin, MDPE resin, or PE resin is preferred.

These are medium/low pressure method /+7 ethylene resin with density force 0.9
30~0.97011/3” (ASTM D1505
).

As the production method, there are medium pressure methods such as (1) Phillips method and (2) 5 standard method, and low pressure methods include a method of polymerizing catalytic metal tyrene using Zlsgler catalyst gold.

L-LDPK resin that can be used in the present invention, MDPE i
resin or HDPE resin has a density of 0.930 to 0.9701
/ piece 3, melt index (hereinafter referred to as Ml) is 0
603-5.0II/10 minutes (ASTM D-1238
) medium density and high density? It is polyethylene resin. Preferably, the density is 0.9317 apr” or more OL-L
DPK tree & example, t how#) ('Nux 3520L, Kurt Sex φ3521 L
(Mikata Petrochemical): Stamilex "4048,"
Na4016, Na4046 (08M companies): Xo-
61500-38, Xo-61500-37, Xo-6
1500-96 (more than Dow Chemical Company) etc. and density is 0
．． It is an HDPE resin of 940.9 or more. Specific examples of product names include Sashichik-HD (Asahi Kasei), Shorex (Showa Denko), Sumikasen Hard (Sumitomo Chemical), Chisso Polyethylene (Chisso), Nirasan Polyethylene (Nissan Maruzen Polyethylene), and Hizex (Mikata Oil). chemistry),
Shiraishi Stafren (Japan Petrochemical), Tubachik (Mitsubishi Kasei), Yucalon HD (Mitsubishi Yuka), Chubu Polyethylene (
Toyo Soda), Idemitsu? Examples include polyethylene (Idemitsu Petrochemical) and Tonen Polyethylene (Tonen Petrochemical).

Particularly preferred is a low-pressure method with a linear structure with few branches and a high crystallinity density of 0.945 to 0.960 Ji' 7c
m”, high density I with Ml of 0.05 to 1.5!i/10 min
It is polyethylene resin.

As the thermoplastic resin, 4-lipropylene resin can also be used as well as MDPE resin or HDPE resin. This Isfa Piren 4! I fats include Pomotaigu I lipropylene resin, random type 4 lipropylene resin which is an ethylene-propylene copolymer resin, and 10 Tsukutaig I ligropylene resin.

The polymerization method uses titanium tetrachloride (T) in a saturated hydrocarbon solvent.
Typical methods include a method using a composite catalyst (Zigler catalyst) obtained by mixing lC24) and aluminum triethyl 0LtEt3) and a method using a composite catalyst (Natsuta catalyst) that combines titanium trichloride (TICt3) and triethylaluminum (AtEt3). This is an example.

Other polymerization methods include the standard oil method, Phillips method, and sun oil method.

The density of the pp resin that can be used in the present invention is 0.90 to 0.9
1717 cm”, Ml is 1-12 II/10 min.

Specific examples: All product names include Nippon Polygloro (Japan Petrochemical)
, UBE Polypro (Ube Industries), Showa Aroma (Showa Denko), Sumitomo Norglen (Sumitomo Chemical), Chisso Polyglo (Chisso), Mitsubishi Norpren (Mitsubishi Yuka), Tokuyama Polygro (Tokuyama Soda), Mikata Petrochemical Polygro (San Mitsui Noprene (Mikata Toatsu Chemical), etc. The heat-sealed surface of the outer paper has the L-L used for the inner paper.
DPE resin, LDPE resin, EEA resin, and various other thermoplastic resins can be used.

This thermoplastic resin film layer has L-LD of the inner paper.
Various additives may be added similarly to the PE light-shielding film j#i. In addition, by laminating it with other flexible sheet layers, it is possible to further improve physical strength, heat resistance, heat sealability, processing machine suitability, commercial value, etc. As this flexible sheet layer, various types of thermoplastic resin films (including non-stretched, uniaxial molecularly oriented, and biaxially molecularly oriented), such as various polyethylene resins, ethylene copolymer fills, etc.
Known films such as resins, polypropylene resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyamide resins, polycarbonate resins, fluororesins, polyester resins, nylon resins, and modified resins thereof. There is a film of.

Other than these, particularly preferred are various papers, non-woven fabrics,
There are known flexible sheet layers such as synthetic paper, cellophane, etc., cellulose acetate film, polyvinyl alcohol film, warp, perforated film, and foamed sheets of polyethylene, polystyrene, polyurethane, and the like.

If necessary, two co-extruded resin film layers may be used.

Depending on the required characteristics, the above flexible sheet layer can be used alone or in combination of two or more and laminated with the resin film layer used for the outer paper of the present invention. The thermoplastic resin film layer to be laminated on the heat-resistant flexible 7 layer can be made of hot tack and elastic materials such as L-LDPE resin, LDPE Im resin, EVA Ed resin, EEA resin, EMA resin, etc. or mixed resins thereof. Film 1 with good sealing properties
- is preferred.

In the present invention, in order to ensure physical strength and reduce costs, a double bag for photographic light-sensitive materials that ensures the performance of the photographic light-sensitive materials is constructed without using metal foil. Therefore, the total thickness of the L-LDPE optical film layer and thermoplastic resin layer of the inner paper and outer paper used in double bags for photographic materials is determined by the following: Moisture resistance, rigidity, physical strength (tensile strength, tear strength, impact drilling strength, dull test strength), heat seal strength, cut cool property, flatness,
A thickness of 5,011 m or more is required from the viewpoint of durability, prevention of pinholes in the heat seal part, etc., and is particularly important for heavy products, high-sensitivity products, and those that are easily affected by humidity, oxygen gas, sulfur gas, etc. For products, the thickness is 70μm or more, preferably 10μm or more.
A film thickness of 0 μm or more is required. It is preferable that the inner paper accounts for 20 mm or more of the total film thickness in terms of ensuring physical strength, processing suitability, heat sealing strength, light shielding property, etc.

However, the film thickness can be as thick as varnish.
270μm or less in terms of low temperature heat sealability, film slitting suitability, bag making suitability, cut sealability, cost, etc.
Preferably, it is 101 times or more thinner than a conventional LDPE film.

Therefore, the total thickness of both the film layers used for the outer paper and the inner paper is 50 to 270 μm, preferably 70 to 20 μm.
0 μm, most preferably 100-160 #m.

In the inner paper and the outer paper, each film layer may be laminated by a conventional known method.

For example, methods that do not use adhesives include hot plate sealing, in/4' sealing, ultrasonic welding, vibration friction welding, rotational friction welding, and hot air welding.

On the other hand, lamination methods using adhesives include wet lamination, dry lamination, hot melt lamination, extrusion lamination (including coextrusion lamination), coextrusion T-die or inflation 7, and film molding. used. The thickness of the adhesive layer obtained by the extrusion lamination method using thermoplastic resin TLW, which is the most effective method for laminating these materials, is usually 7 μm to 10 μm.
0 .mu.m, preferably 13 .mu.m to 50 .mu.m, but the thickness is determined based on cost, coating speed, total thickness of the laminate, etc., and 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 6 are cross-sectional views of the inner paper of the double bag according to the present invention.

Figure 1 shows the most basic material of the present invention, L-LDPE @ fat containing metal powder or carbon black, a lubricant, and an anti-blocking agent and no metal foil, with a thickness of 40 to 15 μm.
m's L-LDPK! It consists of a single optical film layer of 1 m.

FIG. 2 shows an L-LDPE light-shielding film layer 1b formed by adding metal powder etc. to a mixed resin of HDPK resin and L-LDPK resin so as to have a coo-axis molecular orientation.
They are laminated with an adhesive layer 2 such that their molecular orientation axes intersect.

FIG. 3 shows an L-LDPE light-shielding film rdllllt- similar to that shown in FIG. 1, which is laminated with an adhesive layer 2 on both sides of a flexible sheet layer 3.

FIG. 4 shows a structure in which the L-LDPE light-shielding film layer 1 shown in FIG. 1 and the L-LDPE light-shielding film 1b and adhesive layer 2 shown in FIG. 2 are laminated.

FIG. 5 shows the OL-LDPK light-shielding film layer 11 shown in FIG.
are laminated with adhesive layer 2.

Figure 6 shows the L-LDPE light-shielding film layer 1 in Figure 1.
&t-2T-2 It is molded and laminated using the joint extrusion method.

FIG. 7 to FIG. 14 are cross-sectional views of the second paper of the present invention.

FIG. 7 shows a structure in which a heat-sealing layer 5 as a thermoplastic resin film layer is laminated on a heat-resistant flexible sheet layer 4.

FIG. 8 shows a structure in which a heat-resistant flexible sheet layer 4 and a heat-resistant, moisture-proof, light-shielding film upper layer 6 as a thermoplastic resin film layer are laminated with an adhesive layer 2.

In FIG. 9, the heat-resistant and moisture-proof light-shielding film layer 6 of FIG. 8 is replaced with an L-LDPE light-shielding film layer 1a as a thermoplastic resin film.

Figure 10 shows the heat-resistant moisture-proof light-shielding film/11# of Figure 8.
6 is changed to a heat-resistant and moisture-proof film layer 7 which is a thermoplastic resin film.

In FIG. 11, a uniaxially oriented film 8, which is a thermoplastic resin film layer, is placed on an adhesive layer 2? This is a layered structure.

In FIG. 12, the heat-resistant, moisture-proof, light-shielding film layer 6 in FIG. 8 is replaced with an L-LDPE film layer 9 as a thermoplastic resin film layer.

FIG. 13 shows the heat-resistant and moisture-proof film layer 7 as a single film layer.

Figure 14 shows the heat-resistant and moisture-proof property 7
Two LDPE film layers 9 are laminated together by extrusion.

FIGS. 15 to 20 are cross-sectional views of the inner paper, etc. of a conventional double bag.

FIG. 15 consists of a single layer of LDPE light-shielding film layer 10.

Figure 16 shows a LDPE fM oil light-shielding film layer 10, which is conventionally used in products that particularly require moisture resistance, and an aluminum foil layer 11t-laminated with an adhesive layer 2, and a flexible adhesive layer 2 on the aluminum foil layer 1. This is a 5-layer laminated film in which sheet layers 4 are laminated.

Figure 17 shows a packaging material that requires physical strength, which is conventionally used for the inner paper of double gusset bags for color photographic paper, etc. Figure 16 shows a layer of LDPK resin light-shielding film laminated with an adhesive layer 2 of 10000 t. It is a 7-layer laminated film.

FIG. 18 shows a packaging material in which an L-LDPK light-shielding film layer 1at' aluminum foil layer 11 is laminated with adhesive layers 2 on both sides.

FIG. 19 shows a packaging material in which an L-LDPE light-shielding film layer 1at is laminated in place of the LDPE light-shielding film layer 10 of FIG. 16.

FIG. 20 shows a cross-laminated film in which a light-shielding film layer 12 with -axis molecular orientation is laminated on both sides of an aluminum foil layer 11 with an adhesive layer 2 so that the molecular orientation axes intersect.

The double bag for photographic materials of the present invention is also suitable for packaging photosensitive materials. Photographic materials include silver halide photographic materials, diazo photographic materials, photosensitive resins, self-developing photographic materials, and diffusion transfer photographic materials. Contains all substances that undergo hardening and deterioration).

Specific examples include: 11y-), margarine,
Examples include food products such as miso, wine, and beer, pharmaceuticals, dyes, and other chemical substances such as developing solutions and mordants for dyeing. It is especially suitable as a moisture-proof and light-shielding double bag for photographic materials whose quality is destroyed by slight gases, light, and humidity.

The double-layered bag for photographic materials of the present invention is used in the form of a double-layered flat bag, a double-layered gusseted bag, etc., which has two layers of outer paper and inner paper.

Therefore, a double bag may include at least an outer paper and an inner paper, and it also includes a triple bag or more in which another intermediate paper is inserted between the two.

The method for making double bags depends on the properties of the laminated film used, and conventionally known plastic film bonding methods such as hot plate bonding, impulse bonding, fusing bonding, ultrasonic bonding, and high frequency bonding are available. evening.

In addition, it is also possible to make bags by using an adhesive method using an appropriate glue, an adhesive method using a pressure-sensitive/thermal adhesive, or the like.

[For production]

The double bag for photographic materials of the present invention is composed of specific inner paper and outer paper, and has tear strength, impact puncture strength, and heat seal strength that cannot be achieved with conventional double bags made of packaging materials containing metal foil. Glubutist strength etc. are very good.

Furthermore, bag making can be carried out in a dark room without considering the front and back sides of the inner paper, making the bag making work easier.

〔Example〕

Preferred embodiments of the present invention and their effects will be described below.

Invented product! As the outer paper, the flexible sheet layer 4 corresponding to the embodiment in FIG. For the optical film layer 1m, L-LDPE resin manufactured by Mikata Petrochemical Co., Ltd. (trade name: Urtozex 2021 L, density 0.9201//cm3e Ml) is made by copolymerizing ethylene and 4-methylinthene-1.
2.111 l (0 min), 7 cloves of oil - Nescarbine black ft3% by weight, oleic acid amide t as a lubricant.
L-LDPE with a thickness of 50 μm to which 0.1 wt.
A laminated film in which 1 m of R light film layers were laminated was used.

The inner paper to be combined with this outer paper is the same thickness as that used for the outer paper corresponding to the Jitsuso Jiro in Figure 1, 50 Jim O.
L-LDPE, Ji optical film @ 1 af was used.

Combining this outer paper and inner paper, as shown in Figure 22, the central part is completely heat-sealed continuously, and the bottom part is completely heat-sealed between the outer paper, inner paper, and inner paper, and the two bloods are separated. After folding it in, the needle embossed part was fixed with hot melt. In addition, the exit for several products is made by heat-cooling dots with a gap of 3cm, and after heat-cooling the outer paper, inner paper, and inner paper, they are folded double and fixed with cellochive and a label, and the product is placed in a moisture-proof bag. Shading 2
Made into a heavy gusset bag.

Inventive product B The outer paper is L-L according to the embodiment of the present invention shown in FIG.
DPE light shielding film Jnla″4I: Density is 0.935
117am"Ml 2.1.9710 minutes of Sankata Petrochemical #!L, -LDPE resin (product name Urtozex"3
A laminated film having the same composition and layer structure was used except that the heat-resistant and moisture-proof lotus light film layer 6 was changed to a heat-resistant and moisture-proof lotus film layer 6 made of 521 L).

A moisture-proof and light-shielding double gusset bag with the same packaging form was made using the same packaging material as Invention Product (2) for the inner paper and the same method as Invention (1).

Inventive product■ As the outer paper, the inventive product I of the embodiment shown in Fig. 12 is L.
-LDPK A laminated film was used in which an L-LDPE film layer 9 not containing only Carzan Black was laminated in place of 1 m of the M optical film layer.

As the inner paper, the same L-LDPE light-shielding film layer as in the product (2) of the present invention was used. A moisture-proof and light-shielding double gusset bag with the same packaging form was made by the same method as in the present invention 1.

Product of the present invention■ The outer paper is made of Mikata Petrochemical Co., Ltd. (of the embodiment shown in Fig. 11).
A 100 μm thick cloth 2 is made by laminating a 45 μm thick high-density polyethylene diagonal uniaxial molecular orientation film 8 with a density of 0.960117 cm (trade name HIZEX) with a 1011 m thick OLDPE adhesive layer 2 so that the molecular orientation axis is 90 degrees. A laminated film was used.

As the inner paper, ethylene and octene of the embodiment shown in Figure 81 are used.
L-LDP manufactured by DSM of the Netherlands, which is a copolymer of No. 1
E-resin (trade name: Stamilex"1046).

L-LDPE i-optical film layer 11 having a thickness of 70 μm and having a density of 0.92517 cm”, ME 41710 min), 3 wt.
was used.

Inventive product V As the outer paper, the same laminate as the inventive product I of the embodiment shown in FIG. 9 was used. As the inner paper, a 50 μm thick L-LDPE light-shielding film layer 1a, which is the same as the present invention product I of the embodiment shown in FIG. 13 μm thick on both sides of the 7 pull sheet 3
Using a laminated film laminated with the LDPE adhesive layer 2 of
It was made into a light-blocking double gusset bag.

Invention product ■ As the outer paper, the same laminated film as in Invention Product (2) was used.

The inner paper is high-density polyethylene (trade name) Izex, density 0.96 manufactured by Mikata Petrochemical Co., Ltd., according to the embodiment shown in Figure 2.
01/7cm”) 64.42% by weight of L-LDP, which is a copolymer of ethylene and 4-methylpentene-1.
E-resin (trade name Urtozex+202L).

Density 0.92017cm”, ME 2.1111
l 0 min) 30 heavy oil furnace carmen black 4.5 Jim, oleic acid amide as lubricant
i 0.1 weight 1' blended thickness 45μmOL
- LDPE m Optical film lb A cross-laminated film laminated with 2 DPI adhesive layers with a thickness of 10 cm so that all the molecular orientation axes intersect at 90 degrees was used to make a moisture-proof and light-shielding double-layered flat bag completely sealed on all sides. .

Inventive product ■ Inventive product Uses the same outer paper as summer, and the inner paper is only 50 mm thick.
A moisture-proof/light-shielding double gusset bag was made using the same packaging method as the product I of the present invention, with Jim→90 μm.

Product of the present invention ■ As the outer paper, a heat-sealing layer 5 made of LDPE @ fat with a thickness of 30 μm was directly extruded onto Krupaq paper with a basis weight of 7317 m” as a flexible sheet layer 4 corresponding to the embodiment shown in FIG. A laminated film was used.The inner paper had a density of 0.9359/cps, which corresponds to the exact embodiment shown in FIG.

MI 2.1,! i'/10 minutes Mikata Petrochemical L
-LDPE l fat (product name: Urtozex"3521)
L) oil furnace carbon black 3. O weight flI:S, oleic acid amide Th 0.1 as lubricant
Weight est-doped L-LDPE with a thickness of 150 μm
A moisture-proof/light-shielding double gusset bag with the same packaging form as the product I of the present invention was made using 311 optical film layer 1 and gold using the same method as the product I of the present invention.

Inventive product■ The outer paper is L-LDPE light-shielding film layer 1 shown in Figure 9.
a 'e The flexible sheet layer 4 corresponding to the embodiment changed to the LDPE light-shielding film layer 10 has a basis weight of 7.
31/m2 Kurupak paper with a thickness of 40 Jim OLD
LD with 3% by weight of carbon black me added to PE face fat
There were 10 PE light-shielding film layers and a LDPE adhesive layer 2 having a thickness of 13 μm, which was laminated around the entire circumference of the laminated film. A moisture-proof and light-shielding double gusset bag with the same packaging form was made by using the same inner paper as the product (1) of the present invention and using the same method as the summer product of the present invention.

Inventive product ,! A nine-layer film was used for laminating the f-light film, and the inner paper was L-LDPE, a copolymer of ethylene and 4-methylpentene-1 manufactured by Mikata Petrochemical Co., Ltd., which corresponds to the embodiment shown in FIG. Resin (product name: Urtozex+2021L) 70ffiil and Mikata Petrochemical high-density/reethylene resin (product name: Hizex φ3300F, density 0.9541/am3゜M)
[1,1,S'10 min) 26.9 fift% and oil 7
-1-Thickness 7 made by blending 3 weight t% of Nescar Zano Black and 0.1 weight t's of oleic acid amide as a lubricant.
0 Jim's L -LDPE light shielding film layer 1st-
A moisture-proof and light-shielding double-layer gusset bag was made using the same method as the product I of the present invention and having the same packaging form.

Conventional product l As the outer paper, the same product as the invention product ① was used.

As the inner paper, an oil furnace carton black corresponding to the embodiment shown in Fig. 15 is used. Thickness 15 including triple-1is
A moisture-proof/light-shielding double gusset bag was made using the same method and the same packaging form as the product (2) of the present invention using a single film layer of 0 μm (D LDPE resin light-shielding film layer 10).

Conventional product n A 7 μm thick LDPE resin extrusion adhesive layer 2 was added to a 70 μm thick LDPE resin luminescent film layer 10 with 3 weights of carbon black corresponding to the embodiment shown in FIG. Aluminum foil layer 1
Using a packaging material with a five-layer structure in which bleached kraft paper with a weight of 13,517 m was laminated on the 1Q lamination layer with a 15 μm thick LDPK resin extra fuji adhesion layer 2, the same method as the present invention product ■ was used. , Moisture-proof and light-shielding 1 in the same packaging form
It was made into a heavy gusset bag.

Conventional product■ Corresponding to the embodiment shown in Fig. 17, an additional 15 μm thick L is added on the bleached kraft paper side of the laminated film in which the thickness of the LDPK resin light-shielding film layer lO of conventional product 2 is changed from 70 to 50 μm.
DPE extrusion, thickness 50μ through adhesive layer 2
7 laminated with m OLDPE m fat light-shielding film layer 10
A moisture-proof and light-shielding single-layer gusset bag was made using a packaging material with a layered structure, using the same method and packaging form as the product (1) of the present invention.

Conventional product ■ The outer paper is the same as the present invention product ■, which corresponds to the embodiment shown in Fig. 7, and the inner paper is the same as the present invention product ■. A moisture-proof and light-shielding double gusset bag with the same packaging method was used. , Conventional product V As the outer paper, the present invention product ■ corresponds to the embodiment shown in FIG.
The inner paper was made of high-density polyethylene resin 97 with a thickness of 45 μm and a density of 0.960I/Vice 3 corresponding to the embodiment shown in FIG. A cross 2 laminate in which a light-shielding film layer 12 with a dot-axis molecular orientation is laminated on both sides of an aluminum foil layer 11 with a thickness of 7 μm and an LDPE adhesive layer 2 with a thickness of 10 μm so that the molecular orientation axes intersect at 90 degrees. A moisture-proof and light-shielding double gusset bag was made using a film, in the same manner and in the same packaging form as Product I of the present invention.

The above examples are representative examples of preferred embodiments of the double bag for photographic materials of the present invention, but the present invention is not limited thereto, and other known materials and flexible sheets may be used. It is possible to use outer paper or inner paper in combination with layers.

The above is the layer structure of the present invention product 1-X and the conventional products ① to V.

Tables 1 and 2 show the results of comparing the materials used, the thickness of the band layer, and the characteristics.

As the LDPI extrusion adhesive layer 2 in the examples, Mirason 14 (MI5.11
000 minutes, density 0.91917 cm") Warp, Teiy-*y P2T [Oil Furnace Black 44B manufactured by Mitsubishi Chemical Corporation (average particle size 21 #m, p) 1
7.7) As the LDPE film layer, DFD-0111 (MI 2.41111O, density 0.92317cm) f manufactured by Nippon Unicar was used.

The evaluation in Table 1 is as follows.

Excellent: Very good; Good: Excellent; Acceptable; Needs improvement; Questions not included; Not applicable. The test method is as follows.

dense; JIS K6750 (=ASTllylD
-1505).

Melt inch x (MI) ・ JTS K6
760 (=Ω1238).

*A rbo test strength: The number of times the packaging material is bent using a device based on the US military standard MrL-B131 until a pinhole occurs and the light-shielding property cannot be ensured. A strong and eccentric evaluation with a large number is not good; 2 or more times. A pinhole occurs.

Needs improvement; 3 to 7 times; Fair; 7 to 50 times; Good; 51 to 100 times; Excellent; 101 times or more. , exposed to 80,000 lux light for 1 hour, and the lightfastness is detected and evaluated by the degree of capri of the photographic film.

C Hot tack property: Two pieces of packaging material (width 15 degrees) immediately after heat-sealing at 160°C (temperature 1917-℃)
Determined by the hot peel distance m (cWl) when the open end of is pulled at a peel angle of 22.5 degrees with a load of 4519 on one side.

D Bag making suitability; 737 as shown in Figure 7! A photosensitive material 13 is made of an outer paper 15 made by laminating a 15 μm thick LDPE layer as a heat-sealing layer on a Clupack paper 4 of /- and an inner paper 16 of the packaging material of the present invention, as shown in FIGS. 21, 22, and 23. Judging from the resistance to pinholes when packaged in heavy bags, suitability for heat sealing, curling, etc.

E Sliding angle: Cut out a part of the sheet to be tested,
This is pasted on the bottom of a block measuring 75 meters long and 35 meters wide with a load of 200.9. On the other hand, a part of the sheet to be tested is cut out and pasted on an inclined surface, the sheet surface of the block is placed on the inclined surface, the inclination angle of this inclined surface is completely changed, and the block begins to slide. Read the angle.

F Heat sealing strength L: All two samples with a film width of 15 tea are stacked and heat sealed at the desired sealing temperature with a sealing pressure of 1 kg 7 cm and a sealing time of 1 second. After complete cooling, the seal surface metal is at a 180 degree angle. Determine the load required to punch the bag in y.Next, a specific example of the double bag for photographic material of the present invention will be described with reference to FIGS. 21 to 23.

FIG. 21 shows a packaging bag 14 (
2) It is a cross-sectional view. This packaging bag 14 has an outer paper 15 and an inner paper 1.
As shown in the partial cross-sectional views of FIGS. 7 to 14, the outer paper 15 is composed of a typical layer structure of 7 layers (J-4, !). :M: Formed by laminating plastic resin film layers.

The inner paper 16 is made of the packaging material shown in the partial cross-sectional views of FIGS. 1 to 6. The outer paper 15 and the inner paper 16 are continuously or partially glued at their ends and then folded into one piece.The outer paper 15 and the inner paper 16 are glued together with an adhesive and sealed with a tape 17. FIG. 22 is a cross-sectional view of the central part of FIG. 21 in the right angle direction. Flap 1 in the center
Continuously sealed with a center seal throughout the meal.

FIG. 23 is a schematic cross-sectional view of a packaging bag 19 for black-and-white or color roll-shaped photosensitive materials, such as photographic paper, movie film, printing film, MIX ray film, microfilm, etc. This packaging bag 19 is also composed of an outer paper 15 and an inner paper 16 in the same manner as the packaging bag 14 in FIG. .

〔Effect of the invention〕

The double bag for photographic materials of the present invention has tear strength, R Lugo test strength, impact hole scratching strength, hot tack property, tensile strength,
Suitable for bag making, light blocking properties, moisture proofing properties, and slipperiness.

Good heat sealability etc.

And if the physical strength is guaranteed to be the same, double lending improves the strength of the cylinder test, each physical strength, and moisture resistance, so it is possible to make the wall significantly thinner than conventional products, and as a result, the product has a large width. It is possible to measure cost reduction.

Furthermore, since both sides of the inner paper have substantially the same characteristics, there is no need to consider the front and back sides of the inner paper during bag making, and bag making can be carried out efficiently.

[Brief explanation of the drawing]

Figures 1 to 14 are partial cross-sectional views of the packaging material used for the outer paper and inner paper of the double bag for photosensitive materials of the present invention.
15 to 20 are partial sectional views of packaging materials used in conventional double bags, FIG. 21 is a partial sectional view of an embodiment of the double bag of the present invention, and FIG. The figure is a partial cross-sectional view taken in the right angle direction of the central part of the same as above, and Figure 23 is a schematic cross-sectional view of another embodiment of the double bag. l a I l b ... L-LDPE light shielding film 1
4.2...adhesive layer, 3...flexible sheet layer,
4... Heat-resistant flexible sea Hl, 5... Heat-sealing layer, 6... Heat-resistant and moisture-proof light-shielding film layer, 7...
@ Heat and moisture-proof film layer, 8 - Axial molecular orientation film layer, 9 - L -LDPE film layer, 13 - Photographic material, 15 - Outer paper, 16 - Inner paper. Patent applicant: Fuji Photo Film Co., Ltd. Agent
Patent Attorney 1) Masahiro Naka Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 s9 section Figure 10 Figure 11 Figure 12 Figure 13 Figure 1n! ff Figure 15 Figure 16 Figure 17 Figure 18 Figure 20 Figure 19 Cause 21 Country 22 Figure 23 Prisoner

Claims (6)

[Claims] (1) Linear low-density polyethylene (hereinafter referred to as L-LDPE) consisting of ethylene and α-olefin having 3 to 13 carbon atoms. Contains resin, metal powder or carbon black, lubricant, and anti-blocking agent, and has a thickness of 40 mm. L which is ~150 μm
- An inner paper with LDPE light-shielding film layers located on both the front and back surfaces, and a thickness of 10 mm on the surface provided on the outside of the inner paper and in contact with the inner paper.
JIS Z of a combination of the inner paper and the outer paper, which has an outer paper containing a thermoplastic resin film layer of ~120 μm.
A double bag for photographic materials, characterized by a moisture permeability of 5 g/m^224 h or less according to the 0222 test method. (2) The inner paper is ethylene and 4-methylpentene-1 or hexene-1 having 6 carbon atoms or octene-1 having 8 carbon atoms.
A double bag for photographic material according to claim 1, comprising an L-LDPE light-shielding film layer comprising: (3) Inner paper is high-density polyethylene resin 5-90% by weight
and 10 to 95% by weight of L-LDPE resin and uniaxially oriented L-LDPE light-shielding film layers are laminated with the stretching axes intersecting on both the front and back surfaces. Double bag for photosensitive materials (4) The thermoplastic resin film layer of the outer paper is L-LD of the inner paper.
A double bag for photographic material according to claim 1, 2 or 3, which can be heat-sealed with a PE light-shielding film layer. (5) The heat-sealable thermoplastic resin film layer of the outer paper has heat resistance and moisture resistance higher than that of the L-LDPE light-shielding film layer of the inner paper. heavy bag (6) A double bag for photographic materials according to claims 1 to 3, wherein the front and back sides of the inner paper have substantially the same characteristics.