JPH01260438A - Packing material for photosensitive material - Google Patents

Abstract

PURPOSE:To obtain a packing material for photosensitive materials which is unhazardous for photographic characteristics and capable of securing qualities of the photosensitive material completely, by using a single layered light shielding film comprising a polyolefin resin contg. a specified polyethylene resin and a linear low density polyethylene resin, carbon black, a fatty acid and/or a fatty acid compd., and an antioxidant, for a packing material. CONSTITUTION:The single layered light shielding film comprising the polyolefin resin consisting of 0.5-40wt.% polyethylene resin having 0.6-15g/10min melt index and 0.931-0.965g/cm<3> density, >=40wt.% linear low density polyethylene resin having 0.6-10g/10min melt index and 0.919-0.930g/cm<3> density, 0.1-20wt.% carbon black, >=0.01wt.% fatty acid or the fatty acid compd., and 0.01-2.0wt.% antioxidant, is used for the packing material for photosensitive materials. Thus, the packing material which is not hazardous for photographic characteristics and capable of securing qualities of photosensitive materials completely, is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a packaging material for photosensitive materials, and more specifically, it is a packaging material for photosensitive materials, and more specifically, a single-layer film alone has improved physical strength, light shielding properties, and heat sealability. This invention relates to packaging materials for photosensitive materials.

[Conventional technology]

For materials such as photosensitive materials that lose their quality value when exposed to light, packaging bags that completely block light are used. In addition to the above-mentioned light-shielding properties, this packaging bag must have sufficient physical strength according to the size and weight of the packaged items, such as tensile strength, tear strength, impact puncture strength, etc., and the opening must be sealed by heat sealing. Due to the nature of the process, heat sealability is required. In addition, antistatic properties are also required to prevent charging due to friction between the photosensitive material and the packaging bag.

Conventionally, the resin film used for such packaging bags consists of a high-pressure branched low-density polyethylene (hereinafter referred to as LDPE) resin film layer containing a light-shielding substance, an aluminum foil layer, and a bleached kraft paper layer. There were laminated films laminated sequentially with melt-extruded adhesive layers.

In addition, it is difficult to use single-layer film for packaging bags that require various characteristics, such as light-shielding bags for photographic materials, so it is difficult to use single-layer films for packaging bags that require various characteristics, such as light-shielding bags for photographic materials. There was a thick LDPE resin light-shielding film containing carbon black that was used in some cases for photographic paper.

The present inventors also used uniaxially oriented high-density polyethylene (hereinafter referred to as proposed a laminated film in which an LDPE resin film containing at least one of a light-shielding substance and an antistatic agent was laminated on a cross-laminated film using a resin film (displayed as HDPE) (Japanese Utility Model Publication No. 56-19087). Furthermore, we proposed a packaging material with an inexpensive loss-laminated film with improved heat-sealability and light-shielding properties (Utility Model Publication No. 61-20).
Publication No. 590).

Furthermore, L-LDPE resin, which has a resin composition in which carbon black is added to linear low-density polyethylene (hereinafter referred to as L-LDPE) resin, is used as a packaging material that has high physical strength, excellent heat sealability, and is inexpensive. We proposed a packaging material made of a laminated film using a light-shielding film layer (Japanese Patent Application Laid-Open No. 189936/1983,
2-18547).

Furthermore, as a packaging material using a metallized film, 50% by weight or more of L is added on both sides of the metallized film layer.
- Contains LDPE resin and 0.3 to 3 on one or both sides
A packaging material for photosensitive materials was proposed in which a L-LDPE resin polymer layer containing 0% by weight of a light-shielding substance was laminated (Japanese Patent Laid-Open Publication No. 54934/1983).

[Problem to be solved by the invention]

The conventional laminated film of an aluminum foil layer having a LDPE resin film layer and a bleached kraft paper layer is thick and has high rigidity, so it has poor packaging workability, and also has low physical strength (tear strength) and is difficult to curl. big, expensive,
Heat-sealing properties are poor, and dust may be generated during packaging or transportation, or holes may form, tear, or the heat-sealed portion may peel off, making it difficult to maintain light-shielding, moisture-proofing, and gas barrier properties. there were.

Single-layer LDPE resin light-shielding films containing thick carbon black have low physical strength and poor heat-sealability, making it difficult to ensure 100% quality of photosensitive materials.

Utility Model Publication No. 56-19087 and Utility Model Number 61-205
The packaging material having the cross-laminated film proposed in Publication No. 90 greatly improves physical strength such as tear strength and tensile strength, so it is excellent as a packaging material for heavy substances, and was put into practical use until recently. However, since a uniaxially stretched HDPE resin film is used for the heat-sealing layer, it has high rigidity, poor packaging workability, and poor heat-sealability.Also, variations in the thickness of the adhesive layer and the stretching ratio of the uniaxially stretched HDPE resin film may cause curling. Changes in heat seal strength and physical strength occurred, causing trouble during the processing and packaging process, and sometimes peeling or tearing during the transportation process.

In addition, cross-laminated films, in which a vertically stretched film and a horizontally stretched film are laminated so that their stretching axes intersect, use two types of stretched film forming machines.
It was made of expensive laminated film.

JP-A-61-189936 and JP-A-62-185
Single-layer L-LDPE using a resin composition in which carbon black is added to L-LDPE resin, as proposed in Publication No. 47, etc.
Packaging materials having resin light-shielding films are inexpensive, have good heat-sealing properties, and have excellent tear strength and impact puncturing strength, making them very excellent packaging materials for photosensitive materials. However, when packaging heavy products or photosensitive materials, because the Young's modulus is small, L-LDPE resin light-shielding films do not form holes or tears, but they are stretched and become thinner, making it difficult to ensure sufficient light-shielding and moisture-proofing properties. There was a time. In addition, a film using an L-LDPE resin having a density of 0.925 g/c+1 or less not only lacks lubricity but also tends to cause blocking.

The packaging material proposed in Japanese Patent Application Laid-Open No. 61-54934 is
Although physical strength such as tear strength has been improved, packaging materials in which an L-LDPE resin film layer containing a light-blocking material is laminated on only one side of a metallized film suffers from large curling and poor processing suitability. .

In addition, if L-LDPE resin films with approximately the same melting point are laminated on both sides, unless special processing is applied to the heat sealing device, the outer layer will melt and break, resulting in pinholes and strength deterioration. (It also made it look bad.)

For this reason, laminated films were put into practical use by laminating aluminum vacuum-deposited nylon films, polyester films, etc., which have a high Young's modulus and are heat resistant, but curling is extremely large and these aluminum vacuum-deposited nylon films are expensive. Met.

The present invention solves the above-mentioned problems, and even a single layer film has excellent physical strength, less occurrence of blocking (excellent heat sealability, almost no curling, and no lumpy uneven failures). The purpose of the present invention is to provide a packaging material for photosensitive materials that is safe in terms of photographic performance and can ensure 100% of the quality of the photosensitive material by using it as an inner layer even when multi-layered. When used, the purpose is to easily provide a very expensive moisture-proof and light-shielding bag that has excellent insertion properties for photosensitive materials.

[Means to solve the problem]

The present invention was made to achieve the above object, and was achieved by using a polyolefin resin light-shielding film having a special resin composition.

That is, the packaging material for photosensitive materials of the present invention has a melt index of 0.6 to 15 g/10 minutes and a density of 0.931 to 0.
．． 965g/a+3 polyethylene resin 0.5~40
40% by weight or more of linear low-density polyethylene resin with a melt index of 0.6 to log/10 min and a density of 0.919 to 0.930 g/cffl, and 0.1 to 20% by weight of carbon black. , fatty acid and/or fatty acid compound 0.01% by weight or more, antioxidant 0.01~
This structure is characterized by comprising a single layer polyolefin resin light-shielding film containing 2.0% by weight.

In the packaging material for photosensitive materials of the present invention, the composition of the polyolefin resin light-shielding film used is L-
Because it has a special resin composition that combines LDP E resin and polyethylene resin, it maintains the characteristics of L-LDPE resin film, while making up for its shortcomings with polyethylene resin that has special characteristics, making it even better. indicate a property. It was also found that increasing the haze of the film resulted in an effect of improving the light shielding property by 10% or more. .

The polyethylene resin, which is one of the constituent components of the polyolefin resin light-shielding film used in the packaging material for photosensitive materials of the present invention, has a melt index (JIS K67
Based on the 60 measurement method. (hereinafter referred to as Ml) is 0.6 to 15g
/10 minutes, density (6 according to JIS K6760 measurement method)
is 0.931 to 0.965 g/cd, particularly preferably Ml is 1.0 to 5.0 g/10 min, and density is 0.941 to 0.941.
It is 0.958g/c-.

This specific polyethylene resin is used in an amount of 0.5 to 40% by weight. If it is less than 0.5% by weight, it will not be possible to improve the disadvantages of L-LDPE resin such as low Young's modulus, low tensile strength, blocking, and lack of lubricity, and film formability will be poor, resulting in drawdown and bubble stability. Even if it is possible to form a film due to insufficient properties, it is difficult to put it into practical use because it lacks suitability for bag making due to blocking and one-sided elongation due to insufficient tensile strength.

When the content exceeds 40% by weight, the tear strength decreases, and the longitudinal,
The balance of lateral tear strength deteriorates, making the bag more likely to break.

Moreover, the addition of carbon black deteriorates various physical properties, heat sealability, etc., contrary to the effects obtained in the present invention. Further, the occurrence of lump-like non-uniform failures increases, which not only deteriorates the appearance but also has a negative effect on the photosensitive material.

If the Ml of the polyethylene resin is less than 0.6 g/10 minutes, film formability is poor and molecules are easily oriented in the longitudinal direction, making it difficult to obtain a film with a good balance of longitudinal and transverse physical strength. In addition, lump-like non-uniform failures occur frequently and the photosensitive material is easily damaged (If Ml exceeds 15 g/10 minutes, physical strength decreases, Young's modulus and tensile strength become small,
It has poor film formability and is difficult to put into practical use.

If the density of the polyethylene resin is less than 0.931 g/cj, it is difficult to obtain a polyolefin resin light-shielding film with excellent anti-blocking properties and a high Young's modulus. When the density exceeds 0.965 g/cr1, film formability is poor, and the molecules tend to be largely oriented in the direction of shrinkage, resulting in poor balance between vertical and horizontal physical strength. In addition, bulky and uneven failures occur frequently, making it easy to damage the photosensitive material. Moreover, it is expensive and difficult to put into practical use.

L-L, which is one of the constituent components of the polyolefin resin light-shielding film used in the packaging material for photosensitive materials of the present invention.
DPE resin has an Ml of 0.6 to 10 g/10 min,
L- with a density in the range of 0.919 to 0.930 g/cm3
It is LDPE resin.

L-LDPE resin is called the third polyethylene resin, and is a low-cost, high-strength resin that has the advantages of both medium-low density and high-density polyethylene resins and meets the demands of the times for energy saving and resource saving. This resin is a copolymer obtained by copolymerizing ethylene with an α-olefin having 3 to 13 carbon atoms, preferably 4 to 10 carbon atoms, using a low-pressure method or a high-pressure modification method, and has an ethylene content of 85 to 99.5 mol%. It is a low to medium density polyethylene resin with a straight chain structure with short branches.

α-olefins include butene-1, octene-11hexene-1,4-methylpentene-1, heptene-1,
etc., 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/
cffl The most common L-LDPE resin is 0
．． Many of them fall within the range of 90 to 0.94 g/cI11. Among these, those that can be used in the present invention have a density of 0.
．． 919-0.930g crA L-LDPE resin. Specific examples of this L-LDPE resin by trade name include G Resin, TUFL IN (UCC), Dowlex (Dow Chemical), Sflair"- (DuPont Canada), Marlex (Philips), and Neozex. and Ultzex (Mitsui Petrochemicals), Mekasu Nilex (Japan Petrochemicals), NUC Polyethylene-LL,
Examples include TUFTHENE (Nippon Unicar), Idemitsu Polyethylene L, MORETEC (Idemitsu Petrochemical), and Stamilex (DSM). These L-LD
PE resin accounts for 40% or more of the polyolefin resin light-shielding film.

If it is less than 40% by weight, the effect of adding L-LDPE resin to increase longitudinal and transverse tear strength is small.

In particular, a polyolefin resin light-shielding film containing a single thin layer of L-LDPE resin alone has insufficient tear strength, impact puncture strength, pinhole resistance, etc., and is difficult to put into practical use as a packaging material for photosensitive materials.

If the Ml of the L-LDPE resin is less than 0.6, the fluidity of the resin is insufficient, resulting in poor film formability and low MI.
If it exceeds g/10 minutes, physical strength decreases, tear strength and impact drilling strength become insufficient, and blocking tends to occur.

If the density of the L-LDPE resin is less than 0.919 g/cd, the amount of α-olefin is large, resulting in poor polymerizability and high price, and the Young's modulus and tensile strength are small, making it difficult to achieve the purpose of the present invention with a single layer film alone. It is difficult to obtain film.

When the density exceeds 0.93 h/cd, molecules tend to be oriented in the vertical direction, resulting in poor balance between the vertical and horizontal physical strengths.

In particular, the pinhole resistance becomes insufficient, making it difficult to put the monolayer film into practical use as a film for heavy objects.

Carbon black, which is one of the components of the polyolefin resin light-shielding film used in the packaging material for photosensitive materials of the present invention, can be kneaded or dispersed with the polyolefin resin, does not transmit visible light, ultraviolet rays, etc. Provides light-shielding properties to polyolefin resin films. In addition, carbon black not only improves the tear strength, impact puncture strength, and heat sealing properties of polyolefin resin films, but also prevents oxidation of the resin to prevent blisters, prevents blocking, improves lubricity, and prevents harmful substances such as oxidation and It is the most important substance that plays many roles, such as adsorption of reducing substances and metals, etc.

Carbon black is classified into gas black, oil furnace black, anthracene black, acetylene black, oil smoke, powder smoke, animal black, vegetable black, etc. depending on the raw material.

Among carbon blacks, the pH is 5-9 and the average particle size is 10.
~200 mμ is preferred, and furnace carbon black with a pH of 6 to 9 is particularly preferred. p++ like this
By using carbon black with a large particle size, there is less fogging, less increase or decrease in photosensitivity, high light shielding ability, and excellent crosstalk dispersion. It is possible to obtain a light-shielding film that has a number of advantages such as improved physical strength and improved heat-sealability in which holes are less likely to occur.

In the present invention, the average particle size is 200 mμ or less because it is inexpensive, has a large light blocking ability, and has excellent crosstalk dispersion.
Furnace carbon black having a particle diameter of 50 IIp or less is particularly preferable, and it is also preferable in some cases to use acetylene black, Ketchiene carbon black, or graphite, which are expensive but have excellent antistatic effects.

The above various carbon blacks may be used alone or in combination of two or more types. It is also preferable to improve the conductivity by using metal fibers, carbon fibers, metal powders, etc. in combination.

This carbon black is contained in an amount of 0.1 to 20.0% by weight.

If it is less than 0.1%, the effect of adding carbon black (ensuring light-shielding properties, preventing static electricity, etc.) cannot be expected, and the cost will increase by the amount of kneading cost.

If it exceeds 20.0% by weight, the physical strength of the film, especially the tear strength and impact puncture strength, will decrease, and the heat sealability will deteriorate.

Further, the photosensitive material is contaminated by the carbon black on the film surface, or the carbon black detaches from the film and adheres to the photosensitive material, which frequently causes failures.

The amount of carbon black added is approximately 0.3 to 5 per unit area (nf) of the polyolefin resin light-shielding film.
0g/ffr is better.

Various known methods can be used to blend carbon black into the resin, including the compound method (colored pellets), liquid color method, dry color method, die color granulation method, and masterbatch method. The masterbatch method is preferable in terms of cost reduction and prevention of workplace contamination.

The fatty acids and/or fatty acid compounds that are the constituent components of the polyolefin resin light-shielding film used in the packaging material for photosensitive materials of the present invention are halides and the like that are harmful and have an adverse effect on the photosensitive materials, which are added as polymerization catalysts for the polyolefin resin. In addition to making carbon black harmless by neutralizing it, it also improves the dispersibility of carbon black, prevents blocking, improves slipperiness, and improves bag-making suitability. In addition, deterioration of heat sealability due to bleed-out caused by changes in additives in polyethylene resin films and LDPE resin films over time can also be avoided when using L-LDPE resin, which has excellent contaminant sealing properties, used in the present invention.
Combined with using more than % by weight, it can be completely prevented.

Typical fatty acids used in the present invention include oleic acid, stearic acid, lauric acid, ricinoleic acid, naphthenic acid, octylic acid, phthalic acid, adipic acid, cepatic acid,
These include saturated and unsaturated fatty acids such as acetyl ricinoleic acid and maleic acid.

Representative fatty acid compounds include oleic acid amide, erucic acid amide, stearic acid amide, bis fatty acid amide, magnesium stearate, calcium stearate, zinc stearate, aluminum stearate, barium stearate, calcium laurate, zinc octylate, These include butyl oleate and butyl stearate.

The fatty acid and the fatty acid compound are each used alone or in combination in an amount of 0.01% by weight or more. If it is less than 0.01% by weight, the above-mentioned effects cannot be obtained, and if it is used in excess, various problems will occur, such as a decrease in the amount of resin extruded due to screw slippage, fluctuations in the amount of discharge, bleed-out, and deterioration of heat sealability. Therefore, it is preferably within 7.0% by weight.

The antioxidant, which is one of the constituent components of the polyolefin resin light-shielding film used in the packaging material for photosensitive materials of the present invention, suppresses the formation of lumps due to oxidation of the resin during long-term continuous film molding, and suppresses the formation of lumps in the photographic photosensitive materials. When used as a light-shielding bag for personal use, it is used to prevent pressure scratches, abrasions, and pressure burrs from occurring.

In addition to the above-mentioned problems, when large bubbles occur, heat sealing failure occurs, making it impossible to ensure light-shielding properties, moisture-proofing properties, and gas barrier properties, making it impossible to ensure the quality of the photosensitive material.

By using an antioxidant and carbon black together, a synergistic effect of antioxidant is exhibited.

Typical examples of antioxidants are shown below.

As a phenol type, n-octadecyl-3 (3
',5'-di-t-butyl 4'hydroxyphenyl)propinate, 2,6-di-t-butyl-4-methylphenol, 2.6-di-t-butyl-P-cresol, 2,2°
-methylenebis(4-methyl-6-t-butylphenol), 4,4'-thiobis(3-methyl6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-1-butylphenol) 1, Stearyl-β (3
, 5-di-4-butyl 4-hydroxyphenyl)propionate, 1.1.3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3.5
-)limethyl-2,4,6-tris(3,5-di-t
-butyl-4-hydroxybenzyl)benzene, octadecyl-3-(3,5-di-L-butyl-4hydroxyphenyl)propionate, tetrakis[methylene-3
(3°,5'-di-t-7'thyl-4°-hydroxyphenyl)propionate comethane and the like.

Sulfur-based ones include dilauryl-3,3"-thiodipropionate, similystyl-3,3"-thiodipropionate, laurylstearylthiodipropionate,
Examples include distearyl-3'-thiodipropionate and ditridecyl-3,3'-thiodipropionate.

Examples of phosphorus-based substances include trinonylphenyl phosphite and triphenyl phosphite.

In addition, there are also Plastic Handbook (published by KK Industrial Research Group), pages 794-799, Plastic Additive Data Collection (published by KK Chemical Industry Co., Ltd.), pages 327-329, and 1'L
ASTICS AGE ENCYCLOPEDIA Progress Edition 1986 (published by K K Plastic Age Co., Ltd.) 21
There are various antioxidants disclosed on pages 1 to 212.

The antioxidant is not limited to the use of one type, but two or more types may be used in combination. The antioxidant effect may be improved by using them together. For example, a combination of a phenolic antioxidant and a phosphorus antioxidant, a combination of a volatile antioxidant and a heat-resistant antioxidant, etc.

In particular, 2,6-di-t-butyl-p-cresol (BHT)
) and low-volatility high molecular weight phenolic antioxidants (product name 1reganox 1010+ Iriganox
1076+TopanolCA, Ionox 330
etc.), dilaurylthiodipropionate, distearylthiodipropionate, sialkisphosphate, etc. It is effective to use one or more, especially two or more of them in combination.

The allowable amount of antioxidant to be added varies greatly depending on the type of photosensitive material, but in the case of silver halide photographic materials that utilize oxidation and reduction effects, antioxidants can have negative effects such as fluctuations in sensitivity. The content is preferably 2.0% by weight or less.

Even when the addition amount is within this range, it is preferable to choose a phenolic antioxidant as the main antioxidant.

The polyolefin resin light-shielding film used in the packaging material for photosensitive materials of the present invention can completely prevent blocking even without an anti-blocking agent, but in order to particularly improve tear strength, impact puncture strength, and low-temperature physical strength, density When containing 80% by weight or more of L-LDPE resin of 0.919 to 0.925 g/cffl, various antiblocking agents may be added to completely prevent blocking.

Typical antiblocking agents include silica, diatomaceous earth, calcium silicate, aluminum silicate, talc, magnesium silicate, calcium carbonate, higher fatty acid polyvinyl ester, n-octadecyl urea, dicarboxylic acid ester amide, and the like.

In the present invention, various additives can be added in order to bring out the characteristics of the polyolefin resin light-shielding film used.

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

(Types of additives) (Typical examples) (1) E agents: Phthalate esters, glycol esters, fatty acid esters, phosphate esters, etc. (2) Stabilizers: Lead-based, cadmium-based, zinc-based, alkaline earth metals (3) Antistatic agents; cationic surfactants, anionic surfactants, nonionic surfactants, bifacial active agents, various carbon blacks, metal powders, graphite, etc. (4) Flame retardants: Phosphoric esters, halogenated phosphoric esters, halides, mal substances, phosphorus-containing polyols, etc. (5) Fillers: Alumina, kaolin, clay, calcium carbonate, mica, talc, titanium oxide, silica, etc. (6) Reinforcing agents ;Glass roving, metal fiber, glass fiber, glass milled fiber, carbon fiber, etc. (7) Colorant;Inorganic pigment (AI, FezO=,
Tilt, ZnO.

CdS, etc.), organic pigments (carbon black, dye, etc.) (8) Foaming agent: Inorganic foaming agent (ammonia carbonate.

(9) Deterioration inhibitors; ultraviolet absorbers, antioxidants, metal deactivators, peroxide decomposers, etc. (10) Coupling agents, nidyran-based, Titanate-based, chromium-based, aluminum-based, etc.

It is also possible to add various thermoplastic resins to the polyolefin resin light-shielding film having a special resin composition used in the packaging material for photosensitive materials of the present invention.

, for example, various polyolefin resins such as LDPE resin, MDPE resin, polyprolene resin, propylene-ethylene copolymer resin, EVA resin, EMA resin, EEA resin, EAA resin, ionomer resin, ethylene-unsaturated carboxylic acid copolymer resin, These include ethylene-unsaturated carboxylic acid ester copolymer resins, various ethylene-alkyl ester copolymer resins, and various elastomers.

The packaging material for photosensitive materials of the present invention exhibits particularly great effects when made into a blown film using the polyolefin resin having the above-mentioned special resin composition.

Particularly, among cylindrical photosensitive materials, it is suitable as a package for products called bulk rolls in the industry, which have a diameter of 25 cm or more and a length of 50 cm or more, and have a large volume and weight.

However, the most effective bag is a flat bag or gusset bag made by heat-sealing the bottom of a cylindrical film molded using the blown film molding method.

Laminated film, which is obtained by slitting both ends of a blown film and laminating it with other flexible sheets to form a sheet-like film, is used as a packaging material for silver halide photographic light-sensitive materials because it can add even better properties. Most preferably, it is used as a single layer in bulk rolls of photosensitive materials, pancakes, etc. of magnetic materials as described above, thereby completely reducing costs and ensuring quality.

When used in a packaging bag in the form of a laminated film, the polyolefin resin light-shielding film, which is the packaging material for photosensitive materials of the present invention, is preferably used for the inner layer.

The packaging material for photosensitive substances of the present invention is suitable for packaging various photosensitive products such as magnetic tapes, foodstuffs, pharmaceuticals, and chemical substances in addition to photographic photosensitive materials.

Of these, the most effective are various silver halide photographic materials whose quality is impaired by small amounts of gas, light, or humidity, diazo-sensitive materials, photofixable heat-sensitive materials, photosensitive resin materials, and ultraviolet-curable photosensitive materials. This is a light-shielding bag for photosensitive materials such as photosensitive materials, transfer type heat-developable photosensitive materials, direct positive photosensitive materials, self-developing photosensitive materials, and photosensitive materials for planographic printing (PS plates). However, it is not limited to these (,
It can be used as a variety of packaging materials.

[Effect]

The packaging material for photosensitive materials of the present invention has special performance.
- Since 40% by weight of LDPE resin is used, it ensures excellent tear strength and impact puncture strength with a well-balanced physical strength, especially vertical and horizontal. Furthermore, when carbon black is included in the resin composition of the present invention, conventional LDP
There is no decrease in physical strength or deterioration of heat sealability that occurs with packaging materials for photosensitive materials using E resin or HD PE resin, and on the contrary, when carbon black is added in a range of 10% by weight or less, it is better than a film without carbon black. Tear strength and heat sealability are improved, and oxidation prevention performance is also improved.

In addition, polyethylene resin with specific physical properties is
Since it is used in an amount of 0% by weight, the disadvantages of L-LDPE resin such as low Young's modulus, occurrence of blocking and melt fracture, and crystallization speed are improved while ensuring the excellent properties of L-LDPE resin. In addition, the tensile strength is also L-LDP.
Improved over E-resin film alone. As a result, one-sided elongation during film molding is less likely to occur, and drawdown, wrinkles, and streaks are less likely to occur. Bubble stability is good during inflation film molding, melt fracture is less likely to occur, and smoothness is improved. A light-shielding film with excellent light-shielding properties can be obtained.

In addition, the haze is increased by blending L-LDPE resin and polyethylene resin, and the light-shielding property is improved by 10% or more even with the same amount of carbon black added.

In addition, since an antioxidant, fatty acid, and/or fatty acid compound is used together with carbon black, the dispersibility of carbon black is improved, and the synergistic effect of carbon black and antioxidant prevents the oxidation of the polyolefin resin light-shielding film. Prevent occurrence. It also improves film formability, film slipperiness, and anti-blocking properties.

Further, by using 40% by weight or more of L-LDPE resin, generation of white powder is prevented. There is also almost no carbon black generation, which affects suitability for bag making and packaging.

〔Example〕

Examples of the packaging material for photosensitive materials of the present invention are shown in Figures 1 to 3.
This will be explained based on the diagram.

1 to 3 are partial cross-sectional views showing the layer structure of the packaging material for photosensitive materials of the present invention.

The packaging material for photosensitive materials shown in FIG. 1 consists of a single layer of a polyolefin resin light-shielding film 1a containing carbon black.

The packaging material for photosensitive materials shown in FIG. 2 is composed of three layers: a polyolefin resin light-shielding film layer 1a containing carbon black, and a flexible sheet layer 4 laminated with an adhesive layer 3 interposed therebetween.

The packaging material for photosensitive materials shown in FIG.
It is composed of three layers in which a polyolefin resin light-shielding film layer 1a containing carbon black is laminated via a polyolefin resin light-shielding film layer 1a.

FIG. 4 is a partial cross-section showing the layer structure of the packaging material for photosensitive materials of Comparative Product (2), which consists of a single layer of HDPE resin light-shielding film 5a.

FIG. 5 is a partial sectional view showing the layer structure of the packaging material for photosensitive materials of Comparative Product (1), which consists of a single layer of L-LDPE resin light-shielding film 6a.

FIG. 6 is a partial sectional view showing the layer structure of the packaging material for photosensitive materials of conventional product I, in which the LDPE resin light-shielding film 7a
Consists of a single layer of

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

Inventive product I Polyethylene resin has a MT of 1.1 g/10 min, a density of 0.954 g/cffl, HDPE resin is 1.0% by weight, and Ml is a copolymer resin of ethylene and octene-1.
is 4g/10 minutes, density is 0.925g/cffl,
- 95.85% by weight of LDPE resin, carbon black (oil furnace carbon black 1144B, average particle size 21 mp).

pH7.7, made by Mitsubishi Kasei ■) is 3! %, oleic acid amide is 0.03%, calcium stearate is 0.
．． The packaging material is a single-layer blown film having a thickness of 70 mm and having a resin composition of 0.07% by weight and 0.05% by weight of an antioxidant.

Product of the present invention ■ Polyethylene resin with Ml of 1.1 g/10 min, HDPE resin with a density of 0.954 g/c is 10%, Ml is 2 as a copolymer resin of ethylene and octene-1,
0 g/10 min, L-L with density 0.920 g/cm3
DPE resin is 86.855 juumaru, carbon black is 3
Weight %, oleic acid amide 0.033 weight%, calcium stearate 0.07 weight %, antioxidant 0.0
This is a packaging material made of a single-layer blown film with a thickness of 10 nm and a resin composition of 55 layers.

Inventive product■ Density is 0.935g/cn as polyethylene resin! ,
15% by weight of HDPE resin with MI of 2.0g/10min;
M is an ethylene and 4-methylpentene-1 copolymer resin
1 is 2.1 g/10 min, L-LDPE resin has a density of 0.920 g/cm3, 81.855 heavy circles, carbon black 3% by weight, oleic acid amide 0.03% by weight, calcium stearate 0. This is a packaging material made of a single-layer blown film with a thickness of 70 μm and having a resin composition of 0.07% by weight and an antioxidant of 0.05% by weight.

Comparative product 1 Ml, which is the polyethylene resin of the invention product I, is 1°1 g
/10 minutes, HDPE resin with a density of 0.954 g/d is 9
The packaging material is a single-layer blown film with a thickness of 70 cm and having a resin composition of 7% by weight and 3% by weight of carbon black.

Comparative product■ MI, which is a copolymer resin of ethylene and butene-1, is 1.
0g/10min, L-LD with density 0.890g/cT1
This is a packaging material made of a single-layer blown film with a thickness of 701M, which has a resin composition of 97% by weight PE resin and 3% by weight carbon black.

Conventional product■ Density is 0.923g/crA, MI is 2.4g/1
The above embodiment is a packaging material made of a single layer blown film with a thickness of 70 mm and having a resin composition of 97% by weight of LDPE resin and 3% by weight of carbon black. Although representative examples of embodiments are shown, the present invention is not limited to these, and resin compositions with various commercially available L-LDPE resins and other known materials and thermoplastic resins, and other known materials. A combination with an adhesive layer, an anchor coat layer, a flexible sheet layer, a known surface activation treatment (corona discharge treatment, ultraviolet irradiation treatment, flame treatment, glow discharge treatment, etc.), etc. can be used.

The experimental results are shown in Table 1.

The evaluation is based on the following.

◎...Excellent O...Excellent...Acceptable (within practical limits) M...Problems (improvement required) ×...Not practical *1 Blocking prevention properties Above resin composition After forming and winding the blown film under *3 conditions, it was cut into a size of 100'' x 100'''' with a razor, and judgment was made based on the ease of opening the cut opening.

*2 Comprehensive evaluation of 5 points: heat sealability hot tack property, contaminant heat sealability, heat seal strength, heat seal strength over time, heat seal allowable temperature range *3 Film formability diameter 100mm, ring clearance 1 Comprehensive evaluation of bubble stability, occurrence of drawdown, occurrence of wrinkles and streaks, film thickness, etc. when a blown film with a thickness of 10 um was molded using a ring die of Shizuo at a blow ratio of 1.76. [Effects] The packaging material for photosensitive materials of the present invention satisfies all the characteristics required as a packaging material for photosensitive materials even with just a single layer film; it does not cause blocking, is flexible, has high physical strength, and is suitable for film forming. Excellent properties and heat sealability.

Inflated film can be used as is as a packaging material for large, heavy products such as sealed packages for bulk rolls, or it can easily be used to create packaging bags with excellent moisture and light blocking properties by simply cutting the film to the required size and heat sealing the bottom. It can be obtained cheaply.

In addition, because there is little curling and good heat-sealing properties, packaging workability is also good, and packaging work productivity is high, making it possible not only to reduce the cost of packaging materials but also to reduce costs by saving labor.

[Brief explanation of the drawing]

1 to 3 are partial cross-sectional views showing the layer structure of an example of the packaging material for photosensitive materials of the present invention. 4 and 5 are partial sectional views showing the layer structure of a comparative product, and FIG. 6 is a partial sectional view showing the layer structure of a conventional product. 1a...Polyolefin resin light-shielding film layer 3.3
a...Adhesive layer 4.4a...Flexible sheet layer 5a...HDPE resin light-shielding film layer 6a...L
-LDPE resin light-shielding film layer 7a...LDPE resin light-shielding film layer a; Patent applicant indicating that it contains a light-shielding substance Fuji Photo Film Co., Ltd. Agent Patent attorney Kuninaka Name changed Haka 1 Figure 2 Figure 1 Section 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] Polyethylene resin with a melt index of 0.6 to 15 g/10 min, a density of 0.931 to 0.965 g/cm^3, 0.5 to 40% by weight, a melt index of 0.6
~10g/10min, density 0.919~0.930g/
cm^3 linear low density polyethylene resin 40% by weight
A single-layer polyolefin resin light-shielding material containing 0.1 to 20% by weight of carbon black, 0.01% by weight or more of fatty acids and/or fatty acid compounds, and 0.01 to 2.0% by weight of antioxidant. Packaging material for photosensitive substances characterized by comprising a transparent film