JPH01270535A - Packaging material for photosensitive substance - Google Patents

Abstract

PURPOSE:To contrive formation of a packaging material having a high impact puncture strength and tear strength, excellent in antiblocking properties and good in dispersibility of a light-shielding substance, by providing a resin film layer containing specific two kinds of straight-chain low-density polyethylene resins, the light-shielding substance and an antioxidant. CONSTITUTION:A packaging material for photosensitive substances having a light-shielding straight-chain low-density polyethylene resin film layer with the following composition. (a) 50-95wt.% first straight-chain low-density polyethylene resin having 0.870-0.925g/cm<3> density, 0.5-7.0g/10min melt flow rate and <=105 deg.C Vicat softening point, (b) 5-50wt.% second straightchain low-density polyethylene resin having 0.926-0.950g/cm<3> density, 0.5-7.0g/10min melt flow rate and >=106 deg.C Vicat softening point, (c) 0.1-15wt.% light-shielding substance, (d) 0.01-2wt.% antioxidant and, as necessary, (e) other additives.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the packaging of various photographic materials such as photosensitive materials, particularly X-ray photographic films, lithographic films, cut films, photographic papers, 18th plates, and photosensitive resin films. It relates to packaging materials suitable for.

[Conventional technology]

In general, packaging materials for cutting-edge technology products, such as photosensitive materials, are required not only to completely block light, but also to have gas barrier properties, moisture proof properties, and physical strength (breaking strength, tear strength, impact puncture strength, gelbo test strength, and friction strength). etc.), heat sealability (heat sealing strength, cut sealing properties, hot tack properties, contaminant sealing properties, etc.), antistatic properties, lubricity, low dust generation, flatness, etc. has been done.

In the past, several proposals have been made to satisfy these properties.

The present inventor has already disclosed (Japanese Patent Laid-Open No. 57-6754) a packaging material for photosensitive materials in which the physical strength is improved by combining two layers of uniaxially stretched films.

Further, in a three-layer laminated film formed by laminating a uniaxial molecularly oriented thermoplastic resin film on both sides of a sheet-like foam, the thickness of the sheet-like foam is 0.3 to 2.0 mm,
In addition, a two-layer uniaxially molecularly oriented film with a foaming ratio of 5 to 50 times is prepared by applying a heat-melting adhesive layer to both sides of the foam so that the molecular orientation axes intersect at two angles of 30 degrees or more. The thickness of the laminated film is compressed to 40 to 85% of the theoretical sum of each layer (residual thickness ratio).It has high impact punching strength and Gelbo test strength, and has low curl, especially for heavy objects. We have already disclosed a laminated film that is extremely crooked as a packaging + J material (11.
Publication No. 8).

[Problems to be Solved by the Invention] However, the packaging material disclosed in Japanese Unexamined Patent Publication No. 57-6754 has poor heat sealability, low impact punching strength and low Gelbo test strength, and is easily damaged.

In addition, the packaging material described in JP-A-59-2018'48 is thick and has insufficient antistatic properties for use in high-sensitivity photographic materials. The suitability for heat sealing was poor. Furthermore, the packaging was not suitable for automatic bag making and was extremely expensive.

The present invention solves the problem described in item 1 and prevents the occurrence of lumpy uneven failures, fish eyes, and blocking while ensuring impact drilling strength, tear strength, heat sealability, etc.
The object of the present invention is to improve the dispersibility of a light-shielding substance, increase Young's modulus, tensile strength, etc., and provide a packaging material for photosensitive materials that has excellent film formability.

[Means for solving the problem] The present invention has been made to achieve the above L1 objective,
A first linear low-density polyethylene resin (hereinafter referred to as L - L D P
E) and the second L-L DPE resin, which has good compatibility with the first I, -1 = DPE resin, good anti-blocking properties, and high tensile strength, are combined and packaged. It is made of molded material.

That is, the packaging material for photosensitive materials of the present invention has a density (JI
S K6760) is 0.870 to 0.925g/c+f
l, mel I-flow rate (JIS K6760) is 0
．． 5-7.0g/10min, Vikasoto Softening Point (ASTM
01525) is 105° C. or lower, 50 to 95% by weight of the first linear low density polyethylene resin, and the density (JIS K6
760) is 0.926-0.950g/cm3, melt flow rate (JIS K6760) is 0.5-7.0
r;/10 minutes, hiccup 1-softening point (ASTM D152
5) 5-50% by weight of a second linear low-density polyethylene resin whose temperature is 106°C or higher and 0.1-15% by weight of a light-shielding substance.
and a light-shielding linear low-density polyethylene resin film layer containing 0.01-2% by weight of an antioxidant.

The first and second L-LDPE resins used in the present invention are referred to as third polyethylene resins, and are energy-saving keys that have the advantages of medium-low density and high-density polyethylene resins.
It is a low cost I, high strength resin that meets the demands of the era of resource conservation. This resin is produced by a low-pressure method or a high-pressure modification method using ethylene and an α-alpha compound having 3 to 13 carbon atoms, preferably 4 to 10 carbon atoms.
- It is a copolymer obtained by copolymerizing olefins and has an ethylene content of 85 to 99.5 mol %, and is a low-medium density polyethylene resin having a linear structure with short branches.

α-olefins include butene-1, octene-1, hexene-1,4-methylpentene-1, heptene-1,
etc. are used, and the amount thereof is about 0.5 to 15 mol% of the polymer. The density is generally considered to be that of low-medium density polyethylene resin, but commercially available products have a density of 0.87 to 0.95 g/
Many of them are within the range of cffl.

Please give a specific example of L-LDPE resin by trade name.
G Resin and TUFLIN and NtJ (, -FLX (UCC
), Dowlex (Dow Chemical Company), Sflare (
DuPont Canada Ltd.), Fselen (Susumu Kagaku), Marex (Philips), Fuosex and Urtuzex (Mitsui Petrochemical), Nippon Nilex (Japan Petrochemical), Sumilex (DSM), Idemitsu Polyethylene L and Examples include Moretic (Idemitsu Petrochemical), NUC Polyethylene-LL and TUFTHENE (Nippon Unicar).

To give a typical example of a preferable product name, 4-4-carbon having 6 carbon atoms is artificially added to polyethylene as an α-olefin side chain.
Mitsui Petrochemical ■'s Uru 1 introduced methylpentene-1
There are 61 products, including DSM's Sumilenx, Idemitsu Petrochemical's Moretic, and Dow Chemical's Dowlex, which introduce octene-1 with 8 carbon atoms as the sex and α-olefin side chains (all four companies have liquid phase Obtained by method process - LDP
It is E resin. ).

The first L-LDPE resin has a density of 0.870 to 0.
．． 9-25 g/c. If the density is less than 0.870 g/c, polymerization is poor and blocking is likely to occur.
Moreover, it is expensive and difficult to put into practical use. Density is 0.925g/c
If it exceeds m, the impact drilling strength will decrease, the tear strength will decrease, and it will be difficult to achieve the object of the present invention with the resin composition of the present invention used in combination with the second L-LDPE resin.

The density of this first L-LDPE resin is 0.9.
Ethylene of 25g/cnT or less and α- with 6 or more carbon atoms
A copolymer resin with olefin and a copolymer resin with ethylene and butene-1 having 4 carbon atoms, which has a density of 0.910.
L-LDPE resins with ultra-low densities of g/cm or less are particularly preferred. Typical examples of commercially available products include Efselen from Susumu Kagaku ■ and NUC-F LX from UCC.

Moreover, the MF'R of the first L-'L' DPE resin is 0°5 to 7.0 g/10 min. MFR is 0.5g/10
If it is less than 1 minute, the motor load will be large and melt fracture will easily occur, making it difficult to put it into practical use.
If it exceeds 10 minutes, drawdown tends to occur and the bubble becomes unstable, making it difficult to put it into practical use.

Furthermore, the first L-LDPE resin has a Vicat softening point of 105°C or lower.

When the Vicat softening point exceeds 105° C., the resin composition of the present invention has poor low-temperature heat-sealing properties, loses flexibility and cold resistance at low temperatures, and reduces impact drilling strength, making it impossible to achieve the object of the present invention.

Then, the first L-LDPE resin as described above is
Contains 95% by weight.

If it is less than 50%, the impact puncture strength and tear strength will decrease, flexibility at low temperatures will be lost, and low temperature heat sealability will deteriorate. Moreover, the receptivity to the light-shielding substance decreases, making it impossible to achieve the object of the present invention.

The second (7) L-L D PE resin has a density of 0.
: 926 to 0.950 g/c.

If the density is less than 0.926 g/cJ, the Young's modulus and tensile strength will decrease, and it will stretch when loaded with heavy objects, resulting in thinness, resulting in a decrease in light-shielding, moisture-proofing, and gas barrier properties, and the density will be 0.950 g/cJ.
If it exceeds c/, not only will the polymerizability deteriorate and become expensive, but the molecules will become less oriented in the vertical direction, resulting in a poor balance between vertical and horizontal physical strength, as well as lump-like non-uniform failures, fins, etc. It is more likely to occur.

In addition, the second L-'LDPE resin has an MFR of 0.5 to
7.0g/10min. If the MFR is less than 0.5 g/10 minutes, the motor load will be large and melt fracture will easily occur, making it difficult to put it into practical use.
If g/l' exceeds 0 minutes, drawdown will occur.
The bubble becomes unstable, making it difficult to put it into practical use.

Furthermore, the second L-LI) PE resin has a Vicat softening point of ]06°C or higher.

When the Vicat softening point is less than 106°C, the first
It is difficult to put it into practical use because it cannot improve the drawbacks of E resin, such as blocking, low Young's modulus, and low tensile strength.

Then, the second L-1, DPE resin as described above is 5
~50% by weight.

If it is less than 5% by weight, the drawbacks of the first L-LDPE resin cannot be improved and it is difficult to put it into practical use. If it exceeds 50% by weight, molecules tend to be oriented and the balance between vertical and horizontal physical strength becomes poor. In addition, lumpy non-uniform failures and fish eyes occur frequently, making it difficult to put it into practical use.

A preferable light-shielding substance used in the present invention is the above-mentioned L-LDP.
E: Can be mixed and dispersed in the resin system, has a granular shape,
It is spherical, cylindrical, scale-like, or plate-like, and does not transmit visible light, ultraviolet rays, etc.

Examples of light-shielding substances that can be used in the present invention include various carbon blacks, graphite, iron oxide, zinc white, titanium oxide, clay, aluminum powder', aluminum paste, calcium carbonate, mica, barium sulfate, talc, cadmium pigments, Examples include organic pigments and inorganic pigments such as Bengara, cobalt blue, copper phthalocyanine ftRm, monoazo or polyazo pigments, and aniline black.

Among these light-shielding substances, in terms of quality, cost, light-shielding ability, etc., colored pigments that easily absorb or reflect light, especially various carbon blacks, which are light-absorbing black pigments, and aluminum powder, which is light-reflective, are used. And Aluminum Paste 1 with lower volatile substances removed is preferable.

In particular, when carbon blanks are used, they have antistatic properties, improved physical strength, enhanced antioxidant properties, and light-shielding properties.
It is most preferred because it can improve or ensure various properties necessary for packaging materials for photosensitive materials, such as improved heat sealing properties and improved bronking prevention properties.

Furnace carbon flanks with an average particle size of 200 mμ or less are preferable from the viewpoint of ensuring light-shielding properties and improving cost I and physical strength.Although expensive, light-shielding substances that have an antistatic effect include acetylene carbon black and Ketchiene carbon. Black, graphite, etc. are preferred.

If necessary, it is also preferable to minx two or more types of light-shielding substances according to the required characteristics. In this case, 0.5g/m2 to 50g of light-shielding material with an average particle diameter of 200mμ or less
/m2 Inclusion in a laminated film is particularly preferred as a packaging material for photographic materials that require light-shielding properties. On the other hand, among the carhombra tsuku of Gorera, those with a pH of 5 to 9 and an average particle size of 10 to 200 mμ are preferable, especially p116
~9. Furnace carbon black having an average particle diameter of 50 mμ or less is preferable. By using such pl+ and particle size, there is less fogging, less increase and decrease in photosensitivity, large light shielding ability, and L -
Even when added to the LDP E resin film layer, etc., it has many advantages such as improving physical strength and improving heat sealability, which prevents pinholes from forming due to lumps of carphone blanks and fins. Packaging materials can be obtained.

The above-mentioned light-shielding substance is contained in an amount of 0.1 to 15% by weight.

Typical examples of antioxidants used in the present invention include phenolic antioxidants such as n-octadecyl-3 (3', 5'
- L-butyl 4'hydroxyphenyl)propinate, 2,6 L-butyl 4-methylphenol, 2.
6-dibutyl-p-cresol, 2.2゛-methylenebis(4-methyl-6-t-butylphenol), 4
, 4゛-thiobis(3-methyl-6-t-butylphenol), 4,4゛-butyritenebis(3-methyl-6-t-butylphenol)
-butylphenol), stearyl-β(3,5-di-4-butyl 4-hydroxyphenyl)propionate,
1. L 3-1-lis(2-methyl-4-hydroxy-
5-t-butylphenyl)butane, 1.3.5-trimethyl-2,4,6-1-lis(3゜5-di-t-butyl-4-hydroxyhensyl)henzen, octadecyl-
3-(3,5-di-t-butyl-4hydroxyphenyl)propylene 2-1~, TeI Rakis [methylene-3(3
and 5'-di-1-butyl-4'-hydroxyphenyl)propione-1-)methane.

Examples of sulfur-based compounds include dilauryl-3,3'-thiocyprobione-1, cimilistyl-3,3'-thiodipropionate, laurylstearylthiodipropionate, distearyl-3'-thiocyprobione-1, and citridecyl- Examples include 3,3'-thiodipropionate.

Examples of phosphorus-based materials include 1-linonylphenyl phosphite and l-rifer phosphite l-.

In particular, 2,6-di-t-butyl-p-cresol (BIT)
) and low-volatility high molecular weight phenolic antioxidants (product name 1reganox 1010+ Ireganox
1076+1onox 330+ TopanoICA
etc.), dilauryl thiodipropionate, dilauryl thiodipropionate, sialkis phosphate, etc.
It is effective to use two or more, especially two or more in combination.

The total amount added is 0.01 to 2.0% by weight, whether used alone or in combination of two or more. Added amount is 0
．． If the amount is less than 0.01% by weight, there is almost no effect of addition.

On the other hand, if the amount added exceeds 2.0% by weight, it may have an adverse effect on photographic films that utilize oxidation and reduction effects, and abnormalities may occur in photographic performance. For this reason, it is preferable to add the antioxidant in the minimum amount that will not cause color failure or uneven lump failure.

Particularly preferred are phenolic antioxidants, and commercially available products include various Irganox products from Ciba Geigy, and Sumilizer BtlT and Sumil from Sumitomo Chemical ■.
IzerBP-76, Sumilizer WX-R,
There are Sumilizer BP-101 and the like.

Furthermore, when used in combination with carbon blank etc., the antioxidant effect is synergistically exhibited.

A lubricant can be added to the light-shielding L-LDPE resin film layer of the present invention in order to improve film moldability, lubricity, and processing suitability.

The lubricants preferably used in the present invention include fatty acid amide-based, acetylamine-based, silicone-based and fatty acid metal salts.

(1) Oleic acid amide lubricant: Armoslip CP, (Lion Akzo), Neutron (8Kiseika), Neutron E-18 (Nippon Sakka), Amide 0 (Nitto Chemical), Alflo E-10 ( (NOF), Diamitsu ○-200 (Nippon Kasei), Diamit G-200 (Nippon Kasei), etc. (2) Erucic acid amide lubricant; Alflow P-10 (NOF), etc. (3) Stearic acid amide lubricant; Alflow S-10 (NOF), Neutron 2 (
(4) Bis fatty acid amide lubricants 1 Bisamide (Nippon Kasei), Diamond 200 His (Nippon Kasei), Armowax BBS (Lion Akzo), etc.

Other alkylamine lubricants include Electro Stripper TS-2 (Kao Soap).

Examples of silicone lubricants include various grades of dimethylpolysiloxane (Shin-Etsu Silicone, Toshi Silicone), and the like.

When used in the packaging of photographic materials, the preferred amount of these lubricants to be added is 0.001 to 1.
It is 0% by weight, and not only can it be added alone, but also two kinds can be used in combination. The fatty acid amide lubricant preferred for the present invention has 8 to 50 carbon atoms, particularly preferably 15 to 35 carbon atoms. However, in the case of fatty acid metal salts and the like that have little lubricating effect, they can be added in an amount of about 5% by weight and used as a dispersibility improver for light-shielding substances.

Moreover, in order to prevent blocking of the light-shielding L-LDPE resin film layer, an anti-blocking agent can be added. Anti-blocking agents include silica, calcium carbonate, talc (magnesium silicate), aluminum silicate, calcium silicates, dicarboxylic acid ester amides, etc. Among these, silica is preferred, and the amount added is preferably 0. 01 to 5.0% by weight. 0.0
If it is less than 1% by weight, the anti-blocking effect will be small and the kneading cost will increase. If it exceeds 5.0% by weight, not only the occurrence of lump-like non-uniform failures increases, but also the physical strength and heat sealability of the film decrease.

This silica preferably has an average particle diameter of 0.3 to 201 m. If it is less than 0.3 pm, the agglomeration is strong and blisters occur frequently, and the anti-blocking effect is also small. When the thickness exceeds 20 μm, silica appears on the film surface, which not only makes the film surface rough but also tends to cause scratches on the photosensitive material.

Moreover, various additives can be added in required amounts to the light-shielding L-LDPE resin film layer as needed.

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

(Additive types) (Representative examples) (1) Plasticizers: Phthalate esters, glycol esters, fatty acid esters, phosphate esters, etc. (2) Stabilizers: Lead-based, cadmium-based, zinc-based, alkaline earth metal-based , organic tin-based, etc. (3) Antistatic agents; cationic surfactants, anionic surfactants, nonionic surfactants, bifacial active agents, various carbon blacks, metal powders, graphite, etc. (4) Difficult Refueling agent: monophosphate, halogenated phosphate ester, halide, inorganic substance, phosphorus-containing polyol, etc. (5) Filler: alumina, kaolin, clay, calcium carbonate, mica1. Talc, titanium oxide, silica, etc. (6) Reinforcing agent; Glass roving, metal fiber, glass fiber, glass milled fiber, carbon fiber, etc. (7) Coloring agent; Inorganic pigment (AI, Fe403.
TiO□.

ZnO, CdS, etc.), organic pigments (carbon blank, dyes, etc.) ('8) Blowing agents; Inorganic blowing agents, (ammonia carbonate, sodium bicarbonate) organic blowing agents, Toroso-based, Ab-based), etc. (9) Vulcanizing agents; Vulcanization accelerators, accelerators, etc. (10)
Anti-degradation agents: UV absorbers, antioxidants, metal deactivators, peroxide decomposition, etc. (11) Coupling agents: Silane-based, titanate-based chromium-based, aluminum-based, etc. (12) Various thermoplastic resins , a deodorizer, an antioxidant, a fragrance agent, a moisture absorbent, a rubber, etc.
It is sufficient if the PE resin film layer is provided, that is, the simplest structure is a light-shielding L-LD PE'
, consisting of a single layer of resin film layer. Also,
Light-shielding L-LDPE It may be a multilayer coextruded film with two or more layers of resin film layers, light-shielding L-LD1]
A multilayer coextruded film with layers other than the E resin film layer may also be used. Furthermore, a laminated film may be obtained by laminating Flexible Sea I. on the light shielding property 17-■ and DPE resin film layer.

This flexible sea I layer may be a thermoplastic resin film, such as various polyethylene resins, ethylene copolymer resins, polypropylene resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyamide resins, polycarbonate resins, polyester resins, etc. known film,
and modified resin films thereof. In addition, metal thin film processed films (typically aluminum vacuum-deposited films), cellulose acetate-I films, cellophane, polyvinyl alcohol, various papers, and various metal foils (
Typical examples include aluminum foil), nonwoven fabric, etc. A particularly preferable flexible sheet layer has a basis weight of 20 to 400 g.
/m of various papers (unbleached kraft paper, semi-bleached rough I paper,
Bleached kraft paper, neutral paper, twisted base paper, bleached sulfide paper, Kurupak paper, Duos), white paperboard, photographic base paper, pure white roll paper, coated paper, imitation paper, glassine paper)
, metal 7ri (aluminum foil, zinc foil, lead foil, iron foil, etc.) with a thickness of 5 to 50 μm, aluminum vacuum-deposited paper, metal processing film (typically aluminum vacuum-deposited thermoplastic resin film J, etc.), etc. There is.

Various known methods may be used to laminate a flexible sheet layer or the like on the L-LDPE resin film layer.

The packaging material for photosensitive materials of the present invention can be used for packaging all kinds of photosensitive materials such as photographic materials, foodstuffs, pharmaceuticals, and chemical substances. In particular, the quality of products whose quality is destroyed by slight gases, light, and humidity [silver saponide photographic materials, Ciaz photographic H materials, photosensitive resins, self-developing photographic feeds, diffusion transfer photographic materials, etc.] Ideal for photographic materials.

When the packaging material for photosensitive materials of the present invention is applied to the above-mentioned photosensitive materials, for example, - double flat bags, - square-shaped flat bags, -2] - self-supporting bags, - heavy gusset bags, double gusseted bags, Single layer L
-1, DPE resin film, multilayer coextrusion I, -LD
It can be used for PE resin film, inner lining of moisture-proof boxes, inner lining of light-shielding boxes loaded in bright rooms, and all known forms of leader paper cylinders.

Depending on the properties of the L-L D l) E fill used, the bag making method may be based on conventionally known plastic film sealing methods such as heat sealing, fusing sealing, impulse sealing, ultrasonic sealing, high frequency sealing, etc. . In addition,
It is also possible to make bags using an appropriate adhesive or pressure-sensitive adhesive.

[Effect]

In the present invention, the first L-LDPE resin has high impact strength and tear strength, good heat sealability, and good dispersibility of the light-shielding substance, and the second L-LDPE resin has good anti-frosting properties and high tensile strength. The light-shielding substance provides light-shielding properties and improves the physical strength of the L-1, DPE resin film layer to -12, and the antioxidant prevents coloring failure from occurring in the resin.

〔Example〕

Examples of the packaging material for photosensitive materials of the present invention - Figures 1 to 8
This will be explained based on the diagram.

Figures 1 to 8 are partial cross-sectional views showing the layer structure of the packaging material for photosensitive materials.

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

The packaging material for photosensitive materials shown in FIG. 2 consists of two layers: a light-shielding L-LDPE resin film layer 1a and a thermoplastic resin film layer 2a containing a light-shielding substance. It is composed of a multilayer coextruded light-shielding film Ia.

The packaging material for photosensitive materials shown in Fig. 3 has two light-shielding properties L - L.
It is composed of a multilayer coextruded light-shielding film Ia consisting of three layers in which an intermediate layer 3 is laminated between DPE resin film layers 1a.

The packaging material for photosensitive substances shown in Fig. 4 is composed of three layers in which an intermediate layer 3 not containing a light-shielding substance is laminated between a light-shielding LDPE resin film Fla and a thermoplastic resin film layer 2a containing a light-shielding substance. It is composed of a multilayer coextruded light-shielding film Ia.

The packaging material for photosensitive materials shown in FIG. 5 is composed of three layers: a light-shielding L-LDPE resin film layer 1a and a flexible sheet N5 laminated with an adhesive layer 4 interposed therebetween.

The packaging material for photosensitive materials shown in FIG. 6 is constructed by directly laminating a heat seal layer 7 on an L-LDPE resin film layer 1a.

The packaging material for photosensitive materials shown in FIG. 7 is constructed by laminating flexible sheets 1 to 5 on the multilayer coextruded light-shielding film Ia shown in FIG. 2 with an adhesive layer 4 interposed therebetween.

The packaging material for photosensitive materials shown in FIG. 8 is constructed by laminating a metal foil 6 and a flexible sheet layer 5 via an adhesive layer 4 on a multilayer coextruded light-shielding film Ia shown in FIG.

Next, the results of an experiment comparing the characteristics of the products I to (1) of the present invention, comparative products I to (2), and conventional product I will be explained.

Invention product 1 The first I--L DPE resin has a density of 0.920
g/crlY.

L-LDPE resin (Urtozex; Mitsui Co., Ltd.), which is a copolymer resin of ethylene and 4-methylpentene-1 having 6 carbon atoms, has an MFR of 2.0 g/10 minutes and a Vicat softening point of 93°C. (manufactured by Petrochemical Co., Ltd.) was used, and a 60-layer footrest was used.

The second L-LDPE resin has a density of 0.940 g/cf
fl.

MFR is 2.1g/10min, Vicat softening point is 115℃
L-LDPE resin (Urtozex; manufactured by Mitsui Oil Co., Ltd.), which is a copolymer resin of ethylene and 4-methylpentene-1 having 6 carbon atoms, was used, and the content was 36.8% by weight.

The light-shielding substance is furnace carbon black (#44B; manufactured by Mitsubishi Kasei ■) with an average particle size of 21 mμ and a pH of 7.7.
was added in an amount of 3% by weight.

The antioxidant contains 0.05% by weight of stearyl-β(3,5-di-4-hydroxyphenyl)propionate, a phenolic antioxidant, and tetrakis[methylene-3
(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate comethane was added in an amount of 0.15% by weight, a total of 0.20% by weight.

Product of the Invention (2) Same as Product I of the Invention, except that the amounts of the first L-LDPE resin and the second L-LDPE resin were reversed.

Inventive product■ The first L-, ID PE resin has a density of 0.92
0g/c+fl.

MFR is 2.3g/10min, Vicat softening point is 97”C
L-LDPE resin (Urtozex; manufactured by Mitsui Oil Co., Ltd.), which is a copolymer resin with 4-methylpentene-1 having 6 carbon atoms, was used to bind the resin to 60% by weight.

The second L-LDP”E resin has a density of 0.935
g/cJ.

MFR is 2.1g/10min, Vicat softening point is 113℃
L-LDPE resin (Urtozex; manufactured by Mitsui Petrochemical Co., Ltd.), which is a copolymer resin with 4-methylpentene-1 having 6 carbon atoms, was used, and the amount was 36.8% by weight.

The light-shielding substance and antioxidant are the same as in the product (①) of the present invention.

Inventive product ■ The first L-LDPE resin has a density of 0.920 g/cm
3. MFR is 2.1g/10min, Vicat softening point]-
L-1, which is a copolymer resin with 4-methylpentene-1 having 6 carbon atoms at 00°C, was used at 60% by weight using L-1, DPE resin (Ul I ~ Sex; manufactured by Mitsui Oil ■). .

The second L-LDPE resin has a density of 0.930g
/cm3, MFR is 2.1 g/10 min, Vicat softening point is 1.09°C, and L-LD I) E resin (Urtsessox) is a copolymer resin with 4-methylpentene-1 having 6 carbon atoms. ; made by Mitsui Oil ■), and the amount was 36.8% by weight.

The light-shielding substance and antioxidant are the same as in Invention Product 1.

Comparative crystal ■ The second L-LDPE resin used in the present invention ■
6.8% by weight was used.

The light-shielding substance and antioxidant are the same as in Invention Product I.

Comparative crystal ■ The second L-LDPE resin used in the invention product ■ is 9
6.8% by weight was used.

The light-shielding substance and antioxidant are the same as in Invention Product I.

Comparison product■ The first L-LDPE resin used in the invention product I was 96.8
% by weight was used.

The light-shielding substance and antioxidant are the same as in the product (①) of the present invention.

Conventional product I Density is 0.923g/cm3, MFR is 2.4g/10
LDPE resin with a Vicat softening point of 93° C. was used.

A blown film with a thickness of 70 mm was formed using a ring die with a lip clearance of 1 mm and a blow ratio of 1.76.

The experimental results are shown in Table 1.

The evaluation is based on the following.

◎...Excellent ○...Excellent...Acceptable (within practical limits) M...Problems (improvement required) ×...Not practical *A Anti-blocking properties Above film molding After winding up the blown film made according to the contents, fold diameter 330mm x 22
It was cut to 0 mm with a razor, and judgment was made based on the ease with which the cut opening could be opened.

*B The film to be tested for peeling voltage is 35mm wide and 1350mm long.
Make a nn+ endless belt and use this heddle with a load of 5
The peeling voltage was measured using a voltmeter (manufactured by Shinra Kagaku KK) when it was fed between a 00g SUS roller (stainless steel) and a SUS roller at a speed of 12 m/min.

*C film formability Motor load (current value), bubble stability, frost line position, fish eyes, bumps, film wrinkles, film thickness unevenness, etc. when forming the blown film of the present invention using a blown film forming machine Evaluated based on total blown film manufacturing suitability.

*D Dispersibility of carbon black A blown film containing the carbon black of the present invention is evaluated based on the light-shielding property, degree of occurrence of fish eyes and spots, etc. when produced using a blown film molding machine.

*E Bag-making suitability: The melting temperature difference between the inner and outer layers, low-temperature heat-sealability, heat-seal strength, hot-tack property, contaminant-sealing property, and heat-seal strength over time required when making sealed bags using the packaging material of the present invention. This evaluation is based on the ease of manufacturing packaging bags for photosensitive materials, which have excellent properties such as curling, do not generate pinholes, are difficult to tear during distribution, and can be heat-sealed even at low temperatures.

〔Effect of the invention〕

The packaging material for photosensitive materials of the present invention is based on a resin that is a blend of two types of L-LDPE resins, each with its own characteristics, and since it is combined with a light-shielding substance and an antioxidant, it has all the physical properties. It has excellent tear strength and impact puncturing strength, excellent anti-blocking properties, low electrostatic charge, good dispersion of light-shielding substances, less occurrence of bumps and fish eyes, excellent film formability, and heat resistance. It has good sealability, small change in heat-seal strength over time, and excellent bag-making suitability.

[Brief explanation of the drawing]

1 to 8 are partial cross-sectional views showing the layer structure of the packaging material for photosensitive materials. 1a...Light-shielding L-LDPE resin film layer 2.2a
...Thermoplastic resin film layer 3.3a...Intermediate layer 4.4a...Adhesive layer 5.5a...Flexible sheet layer-32=6...Metal foil 7.7a...Heat seal Layer a: Indicates that the layer contains a light-shielding substance. Patent applicant: Fuji Photo Film Co., Ltd. Agent
Patent attorney Seiji Tanaka 1 person procedural amendment (voluntary) May 9, 1989 Commissioner of the Japan Patent Office Yoshi 1) Tsuyoshi Moon 1 Indication of the case Patent application No. 1983-95677 2 Name of the invention Packaging material for photosensitive materials 3. Relationship with the person making the amendment Patent applicant name Fuji Photo Film Co., Ltd. 4 Agent residence Address: 3-21-3 Hatchobori, Chuo-ku, Tokyo 104
-607 No. 5 Column 6 for detailed description of the invention in the specification to be amended Contents of the amendment The contents of the specification are corrected as follows. Corrected parts: Wrong: ``Acetylamine type'', page 15, line 7, ``Argylamine type'', ``Amide lubricant'', ``Amide lubricant'', ``Amide lubricant'', page 15, line 20, ``Bis''
Deleted page 16, line 7 Incorrect "TS-2" Correct rTS-2, Electros 1 to Ripper-TS-3J Page 16, line 9 "Siloxane""Siloxane and its modified products" Page 22, line 6 Incorrect rL-LDPE film” Positive “Light-shielding L-LDPE resin film layer” Page 24, line 7 rL-LDPEJ rLight-shielding L-I-1) P E J or higher

Claims (1)

[Claims] First linear low density polyethylene resin 50 to 95 having a density of 0.870 to 0.925 g/cm^3, a melt flow rate of 0.5 to 7.0 g/10 minutes, and a Vicat softening point of 105°C or less Weight% and density 0.926-0.950
g/cm^3, melt flow rate 0.5-7.0g
/10 minutes, 5-50% by weight of a second linear low-density polyethylene resin with a Vicat softening point of 106°C or higher, 0.1-15% by weight of a light-shielding substance, and 0.01-2% by weight of an antioxidant. A packaging material for photosensitive materials, characterized by comprising a light-shielding linear low-density polyethylene resin film layer containing %.