JP2731958B2 - Packaging materials for photographic photosensitive materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a package having excellent pinhole resistance, impact piercing strength, and tear strength, and having a sharp edge, particularly suitable for packaging various photographic materials. It is about materials.

[Conventional technology]

In general, high-tech products, such as packaging materials for photographic photosensitive materials, not only completely block light, but also have gas barrier properties, moisture proof properties, physical strengths (tensile strength, tear strength, impact puncture strength, gelbo test strength, wear strength, etc.). ), Heat sealing suitability (heat sealing strength, cut sealing property, hot tack property, foreign matter sealing property, etc.), antistatic properties, lubricity, low dust generation, flatness, etc. are required to be satisfied. You. It is very difficult to combine these properties with a single film material, and a packaging material having a plurality of layers has been used in the past.

The present inventors have conducted intensive studies to improve packaging materials for photographic light-sensitive materials, and have improved physical strength by combining two layers of uniaxially stretched films (JP-A-57-6757).
No. 54).

Also disclosed is an inexpensive packaging material in which the innermost layers of a multi-layer co-extruded blown film are adhered to each other by blocking, and have high physical strength and small curl. (JP-A-64-22544), (JP-A-1-110952),
[Problem to be Solved by the Invention] However, the packaging material described in Japanese Patent Application Laid-Open No. 57-6754 is laminated with an adhesive layer. Since it is completely integrated and hardened, there is a problem that the physical strength is reduced, and the arrangement loss is large and expensive.

In addition, Japanese Patent Application Laid-Open Nos. 64-22544, 1-109952 and 1-133736, which solve the above-mentioned problems, are disclosed in Japanese Patent Laid-Open Publication No. Hei 1-133736. Due to the change in temperature, blocking is not performed on the entire surface, wrinkles and air bubbles are generated unevenly,
In general, the blocking adhesive strength was as small as 10 g / 15 mm width or less.

An object of the present invention is to solve the above problems and to provide a packaging material for a photographic light-sensitive material that can freely adjust the adhesive force by blocking without remodeling a ring die or inflation equipment and can reliably block the entire surface. .

[Means for solving the problem]

The present invention, in order to achieve the above object, the innermost layer of the multilayer co-extrusion blown film, i.e., the layer for blocking adhesion, the tackifier and the number average molecular weight is 300-7.
The problem was solved by using a low polymerization degree polyolefin resin of 000.

That is, in the packaging material for a photographic light-sensitive material of the present invention, the innermost layer has a number average molecular weight of 300 to 7000, a low polymerization degree polyolefin resin of 0.05 to 10% by weight, a tackifier 0.05 to 10% by weight, and an antioxidant 0.01 to 0.8. Having a multilayer co-extruded blown film comprising a thermoplastic resin composition containing
It is characterized by comprising a laminated film having an upper and lower symmetric structure in which the innermost layers of the blown film are adhered by blocking.

The packaging material for a photographic light-sensitive material of the present invention has a laminated film in which the innermost layers of a multilayer co-extruded blown film are pseudo-adhered by blocking.

The blocking adhesion of the innermost layer is not completely bonded and fixed so that it is bonded with an adhesive, but is pseudo-adhered in a somewhat flexible state by blocking without using any adhesive, improving physical strength And curl is prevented.

The adhesive force by the above-mentioned blocking has a number average molecular weight of 300
It can be freely adjusted by the amount of the polyolefin resin having a low polymerization degree of up to 7000 and the amount of the tackifier used.For example, in the case of a laminated film alone, the above two components are reduced to reduce the blocking adhesive strength, and the physical strength is large and flexible. When another flexible sheet is laminated on the laminated film, the two components are increased to increase the blocking adhesive strength (for example, 10
g / 15mm width or more) to prevent wrinkles and air bubbles during lamination due to partial space due to insufficient adhesive strength and peeling.

The multilayer coextruded blown film may be composed of two layers, an innermost layer and an outer layer outside the innermost layer, or an intermediate layer may be provided between the innermost layer and the outer layer.

Since the laminated film is formed by blocking and laminating the innermost layers of the multilayer co-extruded blown film, the laminated film has a vertically symmetric structure. To pseudo bond the innermost layer of the multilayer co-extrusion blown film by blocking, for example, when forming a multilayer co-extrusion blown film by a multilayer co-extrusion inflation method,
The innermost layer of the thermoplastic resin composition is brought into pressure contact with a take-off nip roll or a press-fit roll newly provided after the take-off nip roll. Round die (ring die) used for multilayer coextrusion blown film forming machine
There are three types: a lamination method inside a die, a lamination method outside a die, and a laminar flow supply method. In the present invention, any method can be used. Is preferred because

The low polymerization degree polyolefin resin used in the present invention has a number average molecular weight of 300 to 7000, preferably 500 to 6000, and most preferably 1000 to 4000. Representative examples of the polyolefin resin include a polyethylene resin, an ethylene copolymer resin, a polypropylene resin, an ethylene-propylene copolymer resin, and a propylene-α-olefin copolymer resin.

When the number average molecular weight is less than 300, the film formability deteriorates, or bleeds out to the surface of the film with the passage of time and is transferred to a photographic light-sensitive material or the like, causing various problems such as development inhibition and developer contamination. The physical strength of the film also decreases. If the number average molecular weight exceeds 7000, the effect of improving film formability, blocking adhesiveness, and the like will be reduced.

The low-polymerization degree polyolefin resin having a number average molecular weight of 300 to 7000 is contained in the inner layer in an amount of 0.05 to 10% by weight.

If it is less than 0.05% by weight, the effect of improving film formability, blocking adhesiveness, lubricity, etc. is small, and only the kneading cost is increased. If it exceeds 10% by weight, the melt flow rate of the thermoplastic resin composition (hereinafter referred to as MFR) ) Is too large,
Bubbles are easily shaken during the formation of the blown film, and bleed-out is increased, so that the film is too slippery to be wound well and the physical strength of the film is reduced.

 Examples of the tackifier used in the present invention are described below.

Natural products and their derivatives 1. Resins containing polar groups 2.Polymer-free resin Synthetic resin 1.Polymerized resin 2.Condensed resin The tackifier is contained in the innermost layer in an amount of 0.05 to 10% by weight.
If the content is less than 0.05% by weight, the effect of adding the tackifier does not appear,
If it exceeds 10% by weight, the film formed body deteriorates and the strength of the film decreases.

As the thermoplastic resin that is the main component of the innermost layer of the present invention,
For example, polyolefin resin, polyamide resin, polyester resin, PVA resin, polystyrene resin, and the like can be used.

Polyolefin resins, particularly various polyethylene resins, are thin and strong, have appropriate hardness, are easy to handle, and are preferable because they are inexpensive because they are rich in moisture resistance, water resistance, and chemical resistance.
In particular, an ethylene copolymer resin (L-LDPE resin or the like) which is a copolymer of ethylene and an α-olefin is preferable.

Further, in the packaging material for a photographic light-sensitive material of the present invention, it is preferable to add an antioxidant in order to prevent the occurrence of fish eyes and buttocks (hard nonuniform failure).

 Representative examples of the antioxidant are described below.

(A) phenolic antioxidant 6-t-butyl-3-methylphenyl derivative, 2.
6-di-t-butyl-P-cresol, 2,6-t-butyl-4-ethylphenol, 2.2′-methylenebis-
(4-ethyl-6-t-butylphenol), 4.4 ′
-Butylidenebis (6-t-butyl-m-cresol), 4,4-dihydroxydiphenylcyclohexane, alkylated bisphenol, styrenated phenol, 2,6-di-t-butyl-4-methylphenol,
n-octadecyl-3- (3 '/ 5'-di-t-butyl-4'-hydroxyphenyl) propinate, 2.2'
-Methylenebis (4-methyl-6-tert-butylphenol), 4.4'-thiobis (3-methyl-6-tert-butylphenyl), 4.4'-butylidenebis (3-methyl-6-tert-butylphenol) , Stearyl-β (3
-5-di-4-butyl-4-hydroxyphenyl) propionate, 1.1.3-tris (2-methyl-4hydroxy-5-t-butylphenyl) butane, 1.3.5
Trimethyl-2,4,6-tris (3.5-di-t-butyl-4hydroxybenzyl) benzene, tetrakis [methylene-3 (3 '/ 5'-di-t-butyl-4'-
(Hydroxyphenyl) propionate] methane (b) Ketone amine condensation antioxidant Polymerization of 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, 2,2,4-trimethyl-1,2-dihydroquinoline , Trimethyldihydroquinoline derivative (c) Allylamine-based antioxidant phenyl-α-naphthylamine, N-phenyl-β-
Naphthylamine, N-phenyl-N'-isopropyl-
P-phenylenediamine, NN'-diferni-P-
Phenylenediamine, NN'-di-β-naphthyl-P
-Phenylenediamine, N- (3'-hydroxybutylidene) -1-naphthylamine (d) imidazole antioxidant 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole (e) Phosphite antioxidants Alkylated allyl phosphite, diphenylisodecylphosphite, tris (nonylphenyl) phosphite sodium phosphite, trinonylphenylphosphite, triphenylphosphite (H) thiourea antioxidant Thio Urea derivatives, 1,3-bis (dimethylaminopropyl) -2-thiourea (g) Other useful air oxidation antioxidants Dilauryl thiodipropionate Typical commercial antioxidants are shown below.

(1) Phenolic antioxidants; (1) -1. Monophenolic antioxidants Antage BHT, DAH, DBH, SP, LP, LP-1 (Kawaguchi Chemical), Biosol A, N (Osaka Chemical) ), 17 risers
NS-7, SP, 200, M17 (Ouchi Shinko Chemical), BH
T Suwanox, Steerer A1ba, WS (Sekiko Chemical),
Sumilizer A, BHT, L (Sumitomo Chemical), BHA-
Wako (Wako Pure Chemical), Yoshihax BHT, Tominox SS
(Yoshitomi Pharmaceutical), 1rganox 1076 (Musashino Geigy), Am
oco 533 Antioxidant (Amoco chem), Antioxidant KB
(Bayer), Tenox BHT (Eastman chem) “Eihyl” Antiox
idant 698, 701, 703, 733, 762 (Eiyl cor
p), Topanol 354, A, O, OC (ICI), Iono
l, Ionol 99, 100 (Shell chem), UOP7, 19 (UOP
Chem), Naugard BHT, Naugawhite 434 (Unioyal che
m), Age Rite Super (Vanderlilt) (1) -2. Bisphenolic antioxidants Antage Re, W-300, W-400, W-500,
Crystal 2LX (Kawaguchi Chemical), Nokriser NS-
6, 300 (Ouchi Shinko Chemical Industry), Sandant 2246 (Sanke Chemical Industry), Steerer BB, BPS, BPS-R, EP
P, MBP (Sekiko Chemical), Seanox BCS (Cipro Kasei), Sumilizer BBM, MDP, WX, WX-R (Sumitomo Chemical), Suwanox 425 (Maruzen Petrochemical), Yonnox 2246G, 2246R, BB, SR, 425 (Yoshitomi Pharmaceutical), Plastanox425, 2246 (Am Cyanamid), Antioxi
dant BKF (Bayer), “Eihyl” Antioxidant 702, 71
2, 720, 736 (Eihyl Corp), Santowhite cry stal
s, L, MK, powder (Monsant), Ionox 220, 9
01 (Shell Chem), Age Rite Superlite (Vanderbilt) (1) -3. High molecular weight phenolic antioxidant Ceranox 201 (Osaka Seika Kogyo), antioxidant Hoe
chst TMOZ (Hoechst Japan), Irganox1010, 565
(Musashino Geigy), Plastanox 80, 1729 (Am, Cya
namide), Irganox191, 259, 858, 1093, 1222
(Ciba-Geigy), “Eihyl” Antioxidant 796 (Eihyl c
orp), Good Rite 3114, Good Rite 3125 (Good rich), Topano
lCA (ICI), Ionox 330 (Shell Chem) (2) Sulfur-based antioxidants Rasmit, SS (Daiichi Kogyo Pharmaceutical), Kyonox L, DS (Cipro Kasei), Sumilizer TPS (Sumitomo Chemical), DLTP Yoshitomi ", DMTP" Yoshitomi ", DSTP
Yoshitomi (Yoshitomi Pharmaceutical), Plas tanox LTDP, STDP
(Am, Cyanamide) (3) Phosphorus antioxidants JP360, 351, 355, 212, 308, 310, 50
4, 508, JPP100, 613M, 2000, JA805, HBP, JPH3
800, JPM311, JPM313 (Johoku Chemical), Antage TNP
(Kawaguchi Chemical), Nok riser TNP (Ouchi Shinko Chemical), Chlex C, D, M, MD, O, P, T, TD (Sakai Chemical), Sumilizer TNP, TPP ,same
TPP-R, mark 329, PEP-8260 (Sumitomo Chemical Industries).

The antioxidant is preferably contained in the innermost layer in an amount of 0.01 to 0.8% by weight. If the amount is less than 0.01% by weight, the effect of preventing oxidation is small, and resin baking occurs during the formation of an inflation film. If the amount exceeds 0.8% by weight, the film bleeds out to the outer surface of the film with the elapse of time after film formation, causing various adverse effects. In particular, when used for a photographic light-sensitive material, the quality of the photographic light-sensitive material deteriorates, which is not preferable.

In the packaging material for a photographic light-sensitive material of the present invention, a light-shielding substance can be added to each layer of the multilayer co-extruded blown film in order to secure light-shielding properties.

As the light-shielding substance, conventionally known light-shielding substances are used. Among these light-shielding substances, the amount of bleed-out can be reduced, the resin has an antioxidant effect, the cost is low, and the light-shielding ability is large. Therefore, carbon black is preferred.

Particularly preferred examples of classification of carbon black raw materials include gas black, furnace black, channel black, anthracene black, acetylene black, Ketjen carbon black, thermal black,
There are lamp black, oil smoke, pine smoke, animal black, vegetable black and the like. In the present invention, light shielding properties, cost,
Furnace carbon black is preferable for the purpose of improving physical properties, and acetylene carbon black and Ketjen carbon black, which is a modified by-product carbon black, are preferable as light-shielding substances which are expensive but have an antistatic effect. If necessary, it is also preferable to mix the former and the latter according to required characteristics. When used for packaging materials for photographic light-sensitive materials, it is necessary to consider the addition amount, venting, etc. of ketchin carbon black having a large heavy metal content.

Especially pH 6.0-9.0, average particle size 10-120mμ, volatile component 2.
Furnace carbon black having 0% or less and an oil absorption of 50 ml / 100 g or more does not adversely affect the photographic light-sensitive material, and has a large light-shielding ability and is therefore preferable.

In addition, various additives can be used as required in the present invention.

Next, typical examples of the additives will be described below, but the present invention is not limited thereto, and can be selected from all known ones.

The packaging material for a photographic photosensitive material of the present invention has, in particular, physical strength, antistatic property, heat seal strength, moisture resistance, pinhole resistance,
Ideal as a reinforced bag that requires drop strength and suitability for bag making. When the composition contains a light-shielding substance or an antistatic agent, it is most suitable as a light-shielding bag for photographic photosensitive materials.

The photographic photosensitive material packaging material of the present invention is a single flat bag, a double flat bag, a self-standing bag, a single gusset bag, a double gusset bag, a laminated film, an inner stick of a moisture-proof box, an inner stick of a light room loaded light shielding magazine or an inner bag. And any known form such as leader paper.

Depending on the properties of the laminated film to be used, the bag-making method is based on a conventionally known plastic film sealing method such as heat sealing, fusing sealing, impulse sealing, ultrasonic sealing, and frequency sealing. In addition, it is also possible to make a bag by using an appropriate adhesive, an adhesive or the like.

(Operation)

In the packaging material for photographic light-sensitive materials of the present invention, the number average molecular weight of the innermost layer is a low-polymerization degree polyolefin resin having a molecular weight of 300 to 7000 and a tackifier greatly affects the blocking adhesive force, and the blocking adhesive force is adjusted by the amount of these additives. Is done.

〔Example〕

Hereinafter, an embodiment of a packaging material for a photographic light-sensitive material according to the present invention will be described with reference to FIGS. 1 to 7.

1 to 7 are partial cross-sectional views showing the layer structure of the packaging material for photographic light-sensitive material of the present invention.

The packaging material for a photosensitive material shown in FIG. 1 comprises four layers of a thermoplastic resin outer layer 1.1 and a thermoplastic resin inner layer 2.2 laminated on the inside thereof, and these thermoplastic resin outer layer 1 and thermoplastic resin inner layer 2 Is a two-layer coextrusion blown film 3 formed by a round die method two-layer coextrusion blown film forming machine. And the thermoplastic resin inner layer
2.2 is bonded by blocking (blocking bonded portion B), and the blocking laminated film 4 is formed.

The packaging material for photographic photosensitive materials shown in FIG. 2 is the same as the packaging material of FIG. 1, except that a thermoplastic resin inner layer 2a containing a light-shielding substance is used.

The packaging material for photographic photosensitive materials shown in FIG. 3 is the same as the packaging material of FIG. 1 except that a thermoplastic resin outer layer 1a containing a light-shielding substance is used.

The packaging material for photographic light-sensitive material shown in FIG. 4 uses a thermoplastic resin outer layer 1a containing a light-shielding substance and a thermoplastic resin inner layer 2a containing a light-shielding substance. Same as the material.

The packaging material for photographic light-sensitive material shown in FIG. 5 is obtained by processing an aluminum vacuum-deposited layer 7 by processing an aluminum vacuum-deposited layer 7 on a biaxially stretched polyester film 6 via an adhesive layer 5 on the blocking laminated film 4a of FIG. This is a configuration in which an axially stretched polyester film 8 is laminated.

The packaging material for photographic light-sensitive material shown in FIG. 6 comprises six layers of a thermoplastic resin outer layer 1.1, an intermediate layer 6.6, and a thermoplastic resin inner layer 2a containing a light-shielding substance. 1. The intermediate layer 6 and the thermoplastic resin inner layer 2a containing a light-shielding substance are a three-layer co-extruded blown film 9a formed by a round die method three-layer co-extrusion blown film forming machine. Then, blocking adhesion is performed between the thermoplastic resin inner layers 2a, 2a containing the light-shielding substance to form the blocking laminated film 4a.

In the packaging material for photographic light-sensitive materials shown in FIG. 7, a metal layer 10 is laminated on the blocking laminated film 4a shown in FIG. 4 via an adhesive layer 5, and this metal layer 10 contains a light-shielding substance. In this configuration, the flexible sheets 11 are stacked via an adhesive layer 5a.

The product I layer structure of the invention corresponds to FIG.

The thermoplastic resin outer layer 1a has an MFR of 1.1 g / 10 minutes and a density of 0.95.
4g / cm ³ of density homopolyethylene resin 15 wt%, MFR is
2.4 g / 10 min, high-pressure method low-density homopolyethylene resin with a density of 0.923 g / cm ³ 6 wt%, furnace carbon black with an average particle size of 21 mμ 4 wt%, nonionic surfactant (trade name: Electrostripper TS -3, Kao Corporation
MFR containing 0.1% by weight and 0.05% by weight of erucamide
2.1 g / 10 min, thickness of 12 μm mainly composed of ethylene / 4-methylpentene-1 copolymer resin with density of 0.920 g / cm ³
Light-shielding ethylene copolymer resin film.

The thermoplastic resin inner layer 2a is a low-molecular-weight polyolefin resin, a low-molecular-weight polyethylene resin having a number average molecular weight of about 2,000 (trade name: Mitsui High Wax 22) manufactured by Mitsui Petrochemical Co., Ltd.
0MP) 2% by weight, Arakawa Forestry Chemical Co., Ltd. as a tackifier
Alicyclic saturated hydrocarbon resin (Alcon P-9)
0) MF containing 3% by weight, 3% by weight of furnace carbon black having an average particle diameter of 21mμ, 0.05% by weight of a monophenolic antioxidant, and 0.05% by weight of a high molecular weight phenolic antioxidant
Mitsui Petrochemical Co., Ltd. with R of 2.1 g / 10 min and density of 0.920 g / cm ³
And thickness of the main resin made of ethylene-4 methylpentene-1 copolymer resin (trade name: ULTZEX # 2021L)
3 μm light-shielding ethylene copolymer resin film.

The blocking was carried out by a nip roll of a generally used two-layer co-extrusion blown film molding machine to obtain a four-layer blocking laminated film having a total thickness of 50 μm.

The layer structure of the product II of the present invention corresponds to FIG.

The thermoplastic resin outer layer 1a has an MFR of 0.4 g / 10 minutes and a density of 0.96.
This is a light-shielding polyethylene resin film having a thickness of 10 μm and comprising 97% by weight of a high-density homopolyethylene resin of 5 g / cm ^{3 and 3} % by weight of acetylene carbon black (manufactured by Denki Kagaku).

The thermoplastic resin inner layer 2a is composed of the same Mitsui High Wax 220MP 3% by weight as the product I of the present invention as a low polymerization degree polyolefin resin and 4% by weight of a styrene resin (trade name: FTR6080) manufactured by Mitsui Petrochemical Co., Ltd. as a tackifier. %, (supra) acetylene carbon black 7 wt%, monophenol antioxidant 0.05 wt%, MFR is 1.0 g / 10 min containing 0.05 wt% polymer antioxidants, density of 0.890 g / cm ³ Union Carbide ethylene / butene 1 copolymer resin (trade name
NUX-FLX-DEFD-1210, ultra low density polyethylene resin)
Is a light-shielding ultra-low-density polyethylene-based resin film having a thickness of 15 μm and containing as a main resin.

The two-layer co-extruded blown film composed of the two layers was subjected to blocking adhesion in the same manner as the product I of the present invention to obtain a four-layer blocking laminated film having a total thickness of 50 μm.

The layer structure of the product III of the present invention corresponds to FIG.

The thermoplastic resin outer layer 1a has the same thickness of 12 μm as that of the product I of the present invention.
m is a light-shielding ethylene copolymer resin film.

The thermoplastic resin inner layer 2a is a low-molecular-weight polyolefin resin, a low-molecular-weight polyethylene resin having a number average molecular weight of about 4,000 (trade name: Sankyo High Wax) manufactured by Mitsui Petrochemical Co., Ltd.
420P) 3% by weight, as a tackifier Mitsui Petrochemical Co., Ltd.
Of aliphatic yarn hydrocarbon resin (trade name: Hiretsu T-111)
5) MFR containing 3% by weight, 3% by weight of furnace carbon black having an average particle diameter of 21mμ, 0.05% by weight of a monophenolic antioxidant, 0.05% by weight of a polymer type phenolic antioxidant, and 0.1% by weight of an antistatic agent 0.8g / 10min, density 0.924
g / m ² by Mitsubishi Kasei Co., Ltd. high-pressure low-density homopolymer polyethylene resin (trade name Nobatteku -LF-121E) light-shielding pressure method with a thickness of 13μm mainly resin is homo-polyethylene resin film.

The two-layer co-extruded blown film composed of the two layers was subjected to blocking adhesion in the same manner as the product I of the present invention to obtain a four-layer blocking laminated film having a total thickness of 50 μm.

The product IV layer configuration of the invention corresponds to FIG.

The thermoplastic resin outer layer 1a containing the light-shielding substance is a light-shielding ethylene copolymer resin film having the same thickness as that of the product I of the present invention and having a thickness of 12 μm.

The thermoplastic resin inner layer 2a is made of a high-pressure low-density homopolyethylene resin (trade name Novatec-LF-121) as a main resin.
EVA instead of E) manufactured by Mitsui Dupont Polychemical Co., Ltd.
A light-shielding EVA resin film having a thickness of 13 μm and having the same composition as the product III of the present invention except that a resin (trade name: Evaflex # 480) is used.

The two-layer co-extruded blown film composed of the two layers was subjected to blocking adhesion in the same manner as the product I of the present invention to obtain a four-layer blocking laminated film having a total thickness of 50 μm.

Comparative Product I The layer configuration is similar to FIG.

In the product I of the present invention, the light-shielding ethylene copolymer resin film as the thermoplastic resin inner layer 2a has a number average molecular weight of 300 to 7000 except for a low polymerization degree polyolefin resin and a tackifier. Are identical.

Comparative product II The layer configuration is similar to FIG.

In the product III of the present invention, the light-shielding high-pressure method homopolyethylene resin film as the thermoplastic resin inner layer 2a has a number average molecular weight of 300 to 7000 except for the low polymerization degree polyolefin resin and the tackifier, and is completely different from the product III of the present invention. Are identical.

 The test results are shown in Table 1.

Evaluation is based on the following.

◎ ・ ・ ・ Excellent ○ ・ ・ ・ Excellent ● ・ ・ ・ Possible (within practical limit) ▲ ・ ・ ・ Problem (need to be improved) × ・ ・ ・ Not practical * 1 Blocking adhesion Using a two-layer co-extrusion blown film molding machine described on page 29 under film forming conditions,
As shown in the figure, evaluation was made based on the adhesion between the innermost layers when rolled up in a roll. * 2 Wrinkles and streaks When each sample was prepared under the film forming conditions using a two-layer extrusion blown film forming machine described on page 29. Evaluate the degree of wrinkles and streaks by visual inspection. * 3 Lumpy non-uniform failure. Difficulty of occurrence of bumps when each sample is prepared under the film forming conditions using a two-layer co-extrusion blown film forming machine described on page 29. * 4 Film formability Stability of bubbles, roll appearance, etc. when each sample was prepared under the film forming conditions using a two-layer co-extrusion blown film forming machine described on page 29. More comprehensive evaluation [Effects of the Invention] The present invention is configured as described above, so that the blocking adhesive force can be freely controlled. Since it is possible, even if the resin has a large Young's modulus, it can be blocked and adhered, and it can be controlled to an appropriate blocking adhesive force according to the layer structure so that wrinkles, air bubbles, etc. do not occur, and the physical strength is sufficient. can do.

[Brief description of the drawings]

1 to 7 are partial cross-sectional views showing the layer structure of an embodiment of the packaging material for a photographic light-sensitive material of the present invention. FIG. 8 is a diagram showing a situation where a sample is wound by a co-extrusion molding machine. 1.1a ... thermoplastic resin outer layer 2.2a ... thermoplastic resin inner layer 3.3a ... two-layer co-extruded film 4.4a ... ... blocking laminated film 5.5a ... ... three-layer co-extruded film a contains a light-shielding substance. Show. B indicates a blocking adhesive portion.

Claims (1)

(57) [Claims] (1) An innermost layer having a number average molecular weight of 300 to 7000, a low polymerization degree polyolefin resin of 0.05 to 10% by weight, and a tackifier 0.1.
A multilayer co-extruded blown film made of a thermoplastic resin composition containing 05 to 10% by weight and an antioxidant of 0.01 to 0.8% by weight, and having a laminated film in which the innermost layers of the blown film are adhered by blocking. Packaging material for photographic photosensitive material characterized by the following