JPH0659705B2 - Packaging material for photographic materials - Google Patents

Description

The present invention relates to a laminate suitable for packaging photographic light-sensitive materials.

(Prior Art) Various types of laminates have been widely put into practical use,
Various performances are required according to its usage. Properties required for many photosensitive material packaging laminates including photographic light-sensitive materials are that they are not easily broken, curl-resistant, have high impact strength, are flexible, and are easy to heat seal for sealing. And high tensile strength and high elongation at break. Without lowering the properties such as cushioning, flatness, and sliding properties,
By providing an inexpensive laminate that is excellent in tear strength, gelbotest strength, drop strength, impact strength, flexible and has a large elongation at break and does not curl easily in a sealed package In addition to pioneering new applications, such as replacing the light-sensitive packaging of cylindrical containers and the packaging of photographic light-sensitive materials that were previously transported in metal sealed containers with a laminated body, we also have moisture-proof and gas-barrier control that suits the purpose. Alternatively, many practical benefits such as weight reduction of packaging and prevention of breakage can be considered. Japanese Unexamined Patent Publication No. 57-6754 discloses such a packaging material from us.

(Object of the Invention) An object of the present invention is to improve such a packaging material and to provide a laminate suitable as a more practical packaging material for a photographic light-sensitive material, which has a small physical thickness and a large physical strength. .

(Outline of the constitution of the invention) The present invention provides a two-layer thermoplastic resin film layer by an extruded laminated adhesive layer containing a thermoplastic molten resin in a parallel linear shape running in only one direction or in parallel thin continuous strips. A smooth laminated body with a sliding angle of 25 degrees or less that includes three layers that are directly bonded and laminated while maintaining voids in the area other than the adhesive layer. (1) Layer on the side that contacts the photographic light-sensitive material Is a light-shielding substance 0.5
A heat-sealable thermoplastic resin film layer containing ~ 15 wt%, (2) the adhesive layer has a thickness of 8 to 50 μm, a width of 0.1 to 15 mm, and a gap between the adhesive layers of 10 to 100 mm, (3) Any one or two or more layers of the entire laminate is a light-shielding layer containing a light-shielding substance, (4) the two-layer thermoplastic resin film layer has an elongation at break of 150% or more in the vertical direction and a horizontal direction. A packaging material for a photographic light-sensitive material, which has a thickness difference of 200% or more and a thickness difference of 50% or less, and is a packaging material in which curling is prevented and various physical strengths are improved.

Examples of the heat-sealable thermoplastic resin film layer used in the present invention include various polyethylene, various polypropylene, polyisobutylene, polystyrene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-vinyl acetate copolymer (EVA). ), An olefinic copolymer such as an ethylene-acrylic acid ester copolymer (EEA), a copolymer containing propylene as a main component, a polyamide, a polyacetal, a polyvinyl chloride (PVC),
Polyvinylidene chloride (PVDC), polycarbonate,
Examples of the thermoplastic resin such as polyethylene terephthalate (PET), polyphenylene oxide and the like, and one or a mixture of two or more thereof are preferable heat sealable thermoplastic resin films to which the present invention can be effectively applied. The layer is a resin containing 50% or more of a polyolefin resin (including a copolymer of ethylene and a monomer other than ethylene). More specifically, various polyethylenes (especially low-pressure low-density polyethylene, high-pressure low-density polyethylene, high-density polyethylene), ethylene-propylene copolymer, E
An olefinic copolymer such as VA or EEA, polyisobutylene, and a thermoplastic resin containing, as a main component, one or more of these mixed resins are molded (single extrusion, or a T-die forming film including coextrusion of two or more layers). Or a cast-molded film or an inflation-molded film). Also, the film has molecular orientation (including stretching)
Alternatively, it may be non-oriented, and may be subjected to various known processes such as metal thin film process and printing process.

The same thermoplastic resin film layer that can be heat-sealed can be used for the other thermoplastic resin film layer. 50% difference in thickness between the two thermoplastic film layers
It is below, and it is preferable that the strength is about the same.
These thermoplastic resin film layers may be subjected to metal thin film processing (eg, metal vapor deposition film, etc.).

Extruded laminate adhesive layers (hereinafter referred to as vertical streak adhesive layers) that contain thermoplastic molten resin in parallel linear lines that run only in one direction or parallel thin continuous strips (hereinafter referred to as vertical streak adhesive layers) are various adhesives and thermoplastic molten resins, etc. Can be used.

In the present invention, in addition to the above three essential layers, an adhesive layer may be used on the thermoplastic resin film on the side opposite to the heat seal, or other flexible sheet layer may be directly laminated without using the adhesive layer. Further, another heat seal may be directly laminated on the side in contact with the photographic light-sensitive material without using an adhesive layer in the thermoplastic resin film layer in contact with the photographic light-sensitive material.

(Preferred Embodiment) The thickness of the thermoplastic resin film layer (including the heat-sealable thermoplastic resin film layer that adheres to the photographic light-sensitive material) preferable for use as the packaging material of the present invention is 10 to 10.
The thickness is 200 μm, preferably 30 to 150 μm, and most preferably 40 to 100 μm. The film may be molecularly oriented (including stretched) or may be a non-stretched film, but a cylindrical or prismatic photographic light-sensitive material (including a photographic light-sensitive material-containing cylindrical container such as a metal can or a drum can,
When cardboard cylinders, dark boxes, magazines for loading light chambers, etc. are light-shielded, moisture-proof, tightly adhered, and hermetically packaged, the elongation at break without stretching is 150% or more in the vertical direction and 200% or more in the horizontal direction, specifically LD
PE, L-LDPE, EVA, EEA (especially low-pressure normal low-density polyethylene (L-LDPE) is advantageous in that it has excellent strength when a light-shielding substance is added)}, or two or more of these A film formed by using a mixed resin or a resin obtained by adding a synthetic rubber or the like to these resins is preferable. A film obtained by laminating a uniaxial molecular orientation film so that the molecular orientation axes cross each other is particularly preferable because it has a large physical strength. The two thermoplastic resin film layers essential to the present invention may be the same or different, such as the amount of the light-shielding substance added, the film thickness, the resin composition of the film, the presence or absence of molecular orientation, and the draw ratio.

Another layer essential to the present invention, that is, a vertical streak adhesive layer provided between two thermoplastic resin film layers is a layer formed by extrusion lamination and has a gap of 10 to 100 mm, preferably 20 to 80 mm, and most preferably. Is 30-60m
m, the width of the adhesive layer is 0.1 to 15 mm, preferably 0.3
The adhesive layer has a thickness of 8 to 50 μm, preferably 9 to 20 μm, and most preferably 10 to 15 μm.

Typical adhesives include various types of polyethylene, polypropylene, polybutene, and other polyolefin-based thermoplastic resin hot-melt adhesives, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers (EAA). ), Olefin copolymers such as ethylene-acrylic acid ester copolymers, thermoplastic resins such as ionomer resins, hot melt adhesives, and other hot melt rubber adhesives.

More specifically, the polyolefin-based adhesive for extrusion lamination (extrusion) is various polyethylene,
Aggregates made of polyolefin such as polypropylene, polyisobutylene and EPR, and copolymers with ethylene (E
VA, EEA, EAA, etc.) other than ethylene, such as low-pressure low density polyethylene (L-LDPE), in which some other monomer is copolymerized, SurPont of DuPont, and Himilan of Mitsui Polychemicals. Also included are ionomer resins (ionic copolymers) and polyolefins graft-polymerized with polar monomers.

It is desirable that these adhesives have a melting point of 5 ° or more lower than that of the thermoplastic resin film layer to be laminated. If there is such a temperature difference, it is possible to completely perform the hot melt adhesion without adversely affecting the thermoplastic resin film layer.

When any one of the thermoplastic resin film layers is molecularly oriented, the adhesive layer is a thermoplastic resin and has a temperature at which the characteristics of the molecular orientation film are not impaired (when the molecular orientation film is HDPE, approximately 250 to Those that can be bonded at 350 ° C, such as high pressure low density polyethylene (LDPE), ethylene vinyl acetate copolymer (EV
A), ethylene-acrylic acid copolymer (EAA), ethylene-acrylic acid ester copolymer (EEA), ionomer resin, low-pressure low-density polyethylene linear low-density polyethylene (L-LDPE), and polyolefin polar Mitsubishi Yuka's "modic" etc. which graft-copolymerized a monomer can be used.

Parallel line or parallel vertical stripe adhesive layer maintains a certain degree of integrity as a laminate of two layers of thermoplastic resin film layers in a vertical stripe shape with a constant gap, but voids can be formed in other directions Is given. Such partial bonding is necessary, which increases the tear strength, makes it softer and less susceptible to shattering. Further, when the adhesive layer is formed on the entire surface of the two-layer light-shielding film capable of guaranteeing the light-shielding property double, the laminated body is completely integrated and such an effect is lost.

INDUSTRIAL APPLICABILITY The present invention provides a packaging material that is resistant to tearing, impact hole burnout, breakage, etc., has a small curl, is flexible, and is inexpensive. Incidentally, the adhesive is generally static due to the convex portion to the photographic light-sensitive material, friction fog, it is better to apply to the thermoplastic resin film layer of the inner layer in contact with the photographic light-sensitive material, than to the thermoplastic resin film layer of the outer layer. It is advantageous in terms of prevention of pressure fog, scratches, convex shape deformation, and the like.

It is not necessary for the parallel linear vertical streak adhesive layers to be mathematically strictly parallel, and there is no problem in practice even if the lines are discontinuous to some extent within the range in which the two thermoplastic resin films can be integrated.

The packaging material of the present invention is useful for packaging photographic light-sensitive materials. For use for this purpose, it is necessary that at least one layer in the entire laminate has a light-shielding property. For this purpose, 0.1 to 30% by weight of the light-shielding substance may be contained in one or more layers of the two thermoplastic resin film layers, the flexible sheet layer, the heat seal layer, the adhesive layer, and the like. , Colored paper, or metal foil having a thickness of 5 μm or more and 50 μm or less, such as aluminum foil or galvanized thin-layer steel plate, or 5
Laminate other light-shielding layers such as paper with a metal vapor deposition layer of 5Å to 1200Å (eg aluminum vapor deposition paper) or metal thin film processed film (eg aluminum vapor deposition film), or add light shielding properties by printing. You may use the method of.

When the light-shielding substance is contained, the amount is 0.1 to 30 g per unit area (m ² ) of the entire laminate. It is not preferable to add a light-shielding substance of 12 g / m ² or more in the stretched film in the sense that fisheye generation and physical strength are lowered, and the range of 0.1 to 7% by weight is preferable. When it is added to a flexible sheet such as an unstretched film or paper, the content is not limited to this, and the compounding amount can be up to 30% by weight, and up to 30 g per unit area (m ² ). The light-shielding substance refers to all substances that do not transmit visible light and ultraviolet rays, but representative examples are carbon black, aluminum powder, coloring pigments, coloring dyes, titanium oxide, barium sulfate, calcium carbonate, clay, etc. White pigments, various metal powders, various metal fibers and the like. From the viewpoints of quality, cost and light-shielding ability, it is desirable to use various carbon blacks, aluminum powders and aluminum pastes from which low volatile substances have been removed for packaging of photographic light-sensitive materials.

Among the carbon blacks, those having a pH of 5 to 9 and an average particle size of 10 to 50 mμ are particularly preferable in terms of improving the light-shielding property and less deterioration of properties, and the most preferable one is a furnace carbon black having a pH of 6 to 9 and an average particle size of 15 to 30 mμ. .

To add the same amount and improve the light shielding property as much as possible,
It is desirable to mix a light-shielding substance on the inside (the side that comes into contact with the photographic light-sensitive material when packaged, and the side that is heat-sealed in the case of a bag).

The two layers of the thermoplastic resin film and the vertical streak adhesive layer, which are essential to the present invention, are as described above, but other layers may be laminated on this base in the practice of the present invention.

For example, by stacking heat-resistant and flexible sheets such as various types of paper, non-woven fabric, cellophane, stretched thermoplastic resin film, etc. It is possible to improve such points.

In particular, if one of the outermost layers is a non-thermofusible layer or has a melting point of 5 ° C or more higher than that of the innermost layer (the layer to be heat-sealed), it is easier to heat-seal the lower melting side. This is advantageous for producing a bag having excellent heat sealability.

More specifically, as the outermost layer, paper with a thickness of 10 μm or more,
Heat-sealing can be easily performed by using any of aluminum vapor-deposited paper, aluminum vapor-deposited thermoplastic resin film, cellophane, non-woven fabric, cloth, metal foil, and stretched thermoplastic resin film.

Among them, if a paper having a thickness of 30 μm to 190 μm is used as the outermost layer, it is possible to satisfy both the light-shielding property and the heat resistance, so that it is particularly useful when laminated with a molecular orientation film.

On the contrary, the same effect is applied to the innermost layer (the layer to be heat-sealed) at 5 ° C from the non-heat-melting layer or the molecular orientation film of the outermost layer on the opposite side.
It can also be obtained by forming a layer having a low melting point and easily heat-sealed. The heat-sealable layer may be formed by coating or laminating. For example, when a polyester or nylon film is used as the outermost layer as a stretched film, heat sealing is easy if the innermost layer (layer to be heat sealed) is a low density polyethylene film. In addition,
It is particularly useful for packaging a photographic light-sensitive material if the thermoplastic resin film layer or the heat-sealing layer on the side in contact with the photographic light-sensitive material contains 0.1 to 15% by weight of a light-shielding substance.
When the light-shielding substance is contained in only one layer, it is more advantageous to add the light-shielding substance to the innermost layer in order to prevent leakage from the heat-sealed portion in terms of the light-shielding property.

A layer structure that facilitates heat-sealing when the two thermoplastic resin film layers essential for the present invention, which are adhered so that the molecular orientation axes intersect with each other in the longitudinal streak adhesive layer, are uniaxial molecular orientation thermoplastic resin films As an example, one side surface layer (inner heat seal layer side) has a uniaxial molecular orientation film of 5 ° C.
It is useful to form a layer having a low melting point (preferably 10 ° C. or lower) that is easily heat-sealed and contains 0.5 to 15% by weight of a light-shielding substance. The heat-sealing layer has a thickness of, for example, 10 to 80 μm in the case of an extrusion coat and 13 to 120 μm in the case of a casting film for bonding or an inflation film, and various polyethylene, polypropylene, nylon, polyester, ethylene vinyl acetate copolymer ( EV
A), ethylene-ethyl acrylate copolymer (EEA)
A thermoplastic resin film layer such as the above can be used. Particularly preferably, high pressure low density polyethylene (LDP)
E), ethylene vinyl acetate copolymer (EVA),
Ionomer, linear low density polyethylene (L-LDP
E), ethylene-ethyl acrylate copolymer (EEA)
And the like are thermoplastic resin film layers.

When encapsulating a photographic light-sensitive material, the coefficient of static friction is 0.466 (slip angle 25
) Is preferable, and more preferably 0.325 (slip angle 18 degrees) or less. Such properties are achieved by adding a lubricant or matting the surface, or by selecting the material of the film forming the heat-sealing surface (the surface of the film in contact with the photographic photosensitive material) Can be satisfied.

The laminated film produced by the above constitution has excellent curl resistance. Furthermore, it is flexible and has a large elongation at break, tear strength, impact drilling strength, product insertability, gel botest strength,
Since it also has excellent drop strength, it is particularly useful for packaging photographic light-sensitive materials by imparting light-shielding properties.

Preferred embodiments of the present invention are as follows, for example.
That is, a preferable packaging material for a photographic light-sensitive material is a low-pressure low-density polyethylene containing 0.1 to 30% by weight of carbon black, or a high-pressure low-density polyethylene, or a carbon black having a draw ratio of 2.0 to 7.0 times. 0.5 to 7% by weight, the thickness is 15 μm to 120 μm, and the density is 0.94.
HDPE uniaxially stretched g / cm ³ or more, preferably a uniaxially obliquely stretched film (including a film obtained by slitting a longitudinally uniaxially stretched film in a spiral shape) is a vertical stripe polyolefin type (LDPE, EAA) having a constant gap only in the longitudinal direction. , EE
A, L-LDPE, PP, EVA, ionomer, and other polyethylene copolymers) adhesive layer provides an intersection angle of 30 between the uniaxially stretched film (including uniaxial molecular orientation film) and the stretching axis (including molecular orientation axis). The thickness difference between the uniaxially stretched film and the uniaxially stretched film is 15 so that the crossing is more than 15 degrees.
% Of HDPE uniaxially stretched film, preferably a uniaxially obliquely stretched film (including a film obtained by slitting a longitudinal uniaxially stretched film in a spiral shape) is bonded with the polyolefin-based adhesive layer, and carbon black is added to the one or more layers. It is composed of a laminate containing 0.1 to 30 g / m ² in the whole laminate. This packaging material is particularly suitable for a photographic light-sensitive material, and is remarkably improved in elongation at break, price, physical strength, flexibility and curling property.

Further, a flexible sheet that can be laminated on the side opposite to the heat seal layer used as an application of the present invention will be described later. Typical examples of flexible sheets include various types of paper, synthetic paper, aluminum vapor deposition paper, aluminum vapor deposition film, metal foil / nonwoven fabric such as aluminum foil / tin foil, cross yarn, cellophane, cloth, and various thermoplastic resins. Films such as polyethylene (LDPE, MDPE, HDP)
E, L-LDPE, etc.), various polypropylenes, cellulose triacetate, polyesters, polyamides (nylon 66, nylon 6 etc.), polycarbonates, polyvinylidene chloride, polyvinyl chloride, polystyrene, etc., or copolymers containing these as the main components, for example. It is a film made of EVA, EEA or the like or a mixture of two or more kinds of these thermoplastic resins. Polyethylene terephthalate (PE) is more preferable than cost, availability, versatility, and manufacturability.
T), high density polyethylene (HDPE), medium density polyethylene (MDPE), high pressure low density polyethylene (L-
LDPE) and polypropylene (PP), particularly preferably high density polyethylene having a density of 0.9 to 94 g / cm ³ or more. It is effective that these thermoplastic resin films are uniaxially or biaxially molecularly coded. Particularly preferred uniaxial molecular orientation film and low pressure low density polyethylene film (L-LD) that can be used as the two thermoplastic resin film layers essential to the present invention.
PE) will be described in detail. The uniaxial molecular orientation film is a thermoplastic resin, for example, various polyethylene, various polypropylene, polyester, polyamide, polycarbonate, polyvinylidene chloride, polyvinyl chloride, polystyrene or the like, or a copolymer containing them as a main component or 2 of these thermoplastic resins. Mixtures of two or more species. High density polyethylene, medium density polyethylene, low pressure method low density polyethylene and polypropylene are preferred, and LL is particularly desirable.
DPE, thickness 15-120 μm, density 0.94 g / cm ³
The high-density polyethylene described above.

The uniaxial molecular orientation film mentioned here also includes a film in which the molecular orientation rate in the molecular orientation direction is 1.5 times or more higher than the molecular orientation rate in the 90 degree direction. For example, a blown film having a blow ratio of 2 and stretched 3 times in the machine direction is a uniaxially 3 times stretched film.

Further, a uniaxially stretched film (horizontal uniaxially stretched film by a tenter or the like, longitudinal uniaxially stretched film of a known production method) is generally used as the uniaxially molecularly oriented film, but in the present invention, a physical shaping or an inflation film (tubular film) is used.
For example, a film with a large blow ratio for molecular orientation, or a film in which the molecules are strongly oriented in the longitudinal direction and then spirally cut and spread out (for example, at 45 °) is also considered as a uniaxial molecular orientation film. To tell. Examples of known methods for producing uniaxially molecularly oriented films (including uniaxially stretched films) include JP-A-47-34656 and 48-10046.
4, JP-B-40-5319, 47-38621, 47-
39927, 53-18072 and the like.

The molecular orientation may be vertical, horizontal or diagonal, but it is advantageous that the molecular orientation axes of the two-layer molecular orientation film laminated on both sides of the adhesive layer are laminated at an angle of 30 degrees or more.

When it is desired to keep the tensile strength in all directions on average, the crossing angle of the molecular orientation axes (crossing angle) is preferably 90 degrees. Therefore, the longitudinal molecular orientation film and the transverse molecular orientation film may be laminated, or two molecular orientation films with an angle of 45 degrees may be laminated so that the molecular orientation axes are orthogonal to each other.

In the latter case, a molecularly oriented tubular film or a tubular stretch-extruded film may be laminated by a heat-sealing method or the like in the tubular shape without being cut.

When it is desired to strengthen the tensile strength in a certain direction, it is useful to set the crossing angle (crossing angle) to 30 degrees to less than 90 degrees instead of 90 degrees. However, if the crossing angle is made small, the tearing strength in the direction parallel to the molecular orientation axis is increased. Or, since the tensile strength in the orthogonal direction is lowered, it is preferable that the packaging material is generally 30 degrees or more, preferably 45 to 90 degrees.

The molecular orientation ratio and the stretching ratio are selected according to the resin component and the application of the product and are not particularly limited, but the stretching effect becomes clear at a time of 2 to 15 times and contains a light-shielding substance. In this case, the range of 2 to 7 times is particularly preferable from the viewpoint of film quality such as generation of fish eyes.

The thickness of the uniaxial molecular orientation film is also selected according to the desired requirements, but it is 15 μm to 120 μm for use as a packaging material.
m is common.

Next, low pressure normal linear low density polyethylene (L-LDPE)
The film will be described in detail. This L-LDPE film can be used as a heat seal layer and also as a thermoplastic resin film layer essential to the present invention. LL here
A DPE film means that 45% by weight or more is low-pressure normal linear low-density polyethylene (L-LDPE),
It has excellent sealing properties, strength when carbon is added, flexibility, elongation at break, and slip properties.

The rest of the L-LDPE-based polymer other than L-LDPE (referred to as an additive) is preferably substantially high-pressure low-density polyethylene (LDPE), but any thermoplastic resin that can be kneaded with L-LDPE is used. A plastic resin can be used. This mixed resin includes various polyethylene (HDPE, MDPE, LDPE), polyethylene and its copolymer (ethylene / ethyl acrylate copolymer,
One or more of ethylene vinyl acetate copolymer), ionomer resin, polystyrene, polybutylene, polypropylene can be used.

However, from the viewpoint of improving physical properties, polyolefin resin is preferable and LDPE, MDPE, HDPE, PP, EEA, E
It is desirable to use thermoplastic resins such as VA, ionomer, and polybutene 1 alone or in combination of two or more.

Low pressure normal linear low density polyethylene (L-LDPE)
Is an ethylene-α-olefin-based copolymer, and ethylene and an α-olefin having 3 to 13 carbon atoms, preferably 4 to 10 carbon atoms.
It is a copolymer of olefins and is a polyethylene-based polymer having a linear straight chain with a short branch, and has an ethylene content of 80 to 99.5 mol% and an α-olefin content of 0.
Those of 5 to 10 mol% are suitable for the present invention. This low-pressure normal linear low-density polyethylene L-LDPE is generally manufactured by a low-pressure method, and the density is generally low / medium density, but those usable in the present invention are 0.91 to 0.95 g / cm ^3.
Most of them are within the range of, preferably 0.91 to 0.
It is 94 g / cm ³ .

Melt index (M.I. 190 ° C) is 0.2-4
Those of 0 (preferably 0.4 to 15) can be used. Butene-1 and octene-as α-olefins
1, hexene-1, 4 methylpentene-1, etc.,
To improve physical strength, preferably 4-methylpentene-1,
Hexene-1 and octene-1 are used. Specific examples of L-LDPE that can be used in the present invention are Unipol (UCC), Dow Rex (Dow Chemical Co.), Nisseki Linilex (Nippon Petrochemical Co., Ltd.), Sclear (Dupont Canada Co.), Mar. Rex (Phillips), Neo-Zex and Ulto-Zex (Mitsui Petrochemical), Stamilex (DSM) and the like can be mentioned.
Among these L-LDPEs, particularly preferred is an ethylene content of 90 to 99.5 mol%, an α-olefin content of 0.5 to 10 mol%, M. I. 0.4-15g / 10
Min, density 0.91 to 0.94 g / cm ³ , and hexene-1, octene-1, or 4-methylpentene-1 as an α-olefin. The product names are Ultzex (Mitsui Petrochemical), Stamilex (DSM) and the like.

This low-pressure normal linear low-density polyethylene system (L-LDPE)
The film layer may be directly laminated, or the separately manufactured L-LDPE-based film layer may be laminated via an adhesive layer. In the case of the former direct lamination, the thickness is 10 to 80 μm
(More preferably 20 to 50 μm), and 13 to 120 μm (more preferably 35 to 35 μm in the case of laminating the latter separately manufactured).
90 μm) is suitable. L- containing carbon black
Since the LDPE film light-shielding layer has excellent heat-sealing strength, it can be used with conventional high-pressure low-density polyethylene (LDP).
E) A stronger seal is possible with the same thickness compared to the film layer. It is also advantageous to stack a heat seal layer having a lower melting point than the L-LDPE film shading layer on the surface of the L-LDPE film shading layer. Also,
It is also preferable to use the L-LDPE film light-shielding layer itself as a heat-sealing layer from the viewpoint of sealing property.

This tendency becomes particularly remarkable when carbon black is added, and the L-LDPE film light-shielding layer to which carbon black is added can achieve a seal having a thickness at least higher than that of the conventional LDPE light-shielding layer.

It is necessary for the heat-sealing layer to have a light-shielding property in order to secure light-shielding of the photosensitive material package (especially if the heat-sealing layer becomes thick, light enters from the heat-sealing cross section). LDPE has an even greater advantage in that, even if it is contained in carbon black, the strength does not decrease as in LDPE.
On the contrary, it has the property of improving. Therefore, the present invention is particularly useful as a packaging material for a photographic light-sensitive material that requires complete light shielding properties. In addition, it is advantageous not only in terms of cost that the thin layer has sufficient light-shielding properties, but also in that the rigidity can be suppressed, resulting in improved suitability for an automatic packaging machine. The light-shielding substance is 0.1 to 30 g for the laminated body.
/ M ³ is preferable. The addition of carbon black is particularly preferable in the range of 1 to 15% by weight with respect to the L-LDPE light-shielding layer from the viewpoint of improving the strength, but 15 to 30% by weight is preferable when it is desired to improve the antistatic property and the light-shielding property. Can be added within the range. With or instead of carbon black, known organic / inorganic pigments, colorants and the like can be used as a light-shielding substance. Further, when the L-LDPE film light-shielding layer is used as the heat-sealing layer, there is an advantage that the sealing strength immediately after the heat-sealing is high. In the case of L-LDPE, the sealing surface solidifies quickly. Therefore, there is little risk that the seal portion is stretched and thinned to deteriorate the light-shielding property, the strength is reduced, or a pinhole is generated (hot tack property is good).

Another advantage of the L-LDPE film light-shielding layer of the present invention is that it has high surface strength and does not cause scratches. This has an effect of eliminating the problem of black powder generation in the case of a low density polyethylene film in connection with the strength characteristics when carbon black is added.

Further, one of the advantages of the light-shielding property of the L-LDPE film is its slip property. When inserting a product that is a photographic photosensitive material into a packaging material, it is easier to insert it if the friction coefficient is smaller.
Less likely to scratch the product or damage the packaging material. This ease of insertion is particularly important when automatic packaging is performed by a machine. If the product is large and heavy, this sliding property is required more.
It is possible to use one having a slip angle of 7 to 15 degrees on the surface of the L-LDPE layer, which is also excellent in this point as compared with LDPE (18 to 25 degrees).

As described above, the optimum configuration when L-LDPE is used as the thermoplastic resin film layer of the present invention is summarized as L-
The LDPE-based film layer is particularly useful when used on the side in contact with the photographic light-sensitive material.
It is desirable to contain it by weight%. An adhesive layer having a width of 0.1 to 5 mm, a gap of 10 to 80 mm, and a thickness of 0.9 to
The 18 μm parallel line 2 is provided with a band-shaped adhesive layer and laminated with another thermoplastic resin film layer. L-LDPE
The difference in thickness between the system film layer and this layer is preferably 50% or less in the case of the same processing method. With the above structure, a packaging material for a photographic photosensitive material having excellent physical strength can be realized.

The packaging material of the present invention is for packaging a photographic light-sensitive material, and in order to be used for this purpose, it is necessary that at least one layer in the entire laminate has a light-shielding property. For this purpose, it is preferable to include a light-shielding substance in the low-pressure normal low-density polyethylene-based film light-shielding layer, but in order to further complete the light-shielding property, a flexible sheet layer, an adhesive layer, a metal thin film protective layer, a heat A light-shielding substance may be contained in the seal layer, or in any one or more other layers, the antistatic property,
In order to improve moisture resistance, various thermoplastic resin film layers may be adjusted to have a metal thin film thickness of 55Å to 1200Å. Further, a method of adding a light shielding property by printing may be used.

When a light-shielding substance is contained, it is 0.1 to 30 g, preferably 0.5 to 15 g, per unit area (m ² ) of the entire laminate.
Is an appropriate amount. It is not preferable to add 12% by weight or more of the light-shielding substance to the molecularly oriented film in order to reduce the generation of fish eyes and the physical strength.
The amount is in the range of 0.1 to 9% by weight, preferably 1.5 to 7% by weight, but is not limited to this when added to a flexible sheet such as paper. The light-shielding substance refers to all substances that do not transmit visible light and ultraviolet rays, but representative examples include various carbon blacks, aluminum powders, aluminum pastes, coloring pigments, metal fibers, coloring dyes, titanium oxide,
White pigments such as barium sulfate, calcium carbonate and clay,
There are various metal powders and various metal fibers. From the viewpoints of quality, cost and light-shielding ability, it is desirable to use various carbon blacks, aluminum powders and aluminum pastes from which low volatile substances have been removed for packaging of photographic light-sensitive materials.

The light-shielding substance may be a powdery colorant, a paste colorant, a moisture colorant, a masterbatch, a dye / pigment, or a colored pellet depending on the resin used, the machine used, the cost, and the like.

Typical examples of the classification of carbon black, which is a typical light-shielding substance used in the present invention, by the raw material include gas black, oil furnace black, anthracene black, acetylene black, oil smoke, pine smoke, animal black, vegetable black and the like. In the present invention, light-shielding property, cost,
Furnace carbon black is preferable for the purpose of improving physical properties, and acetylene carbon black and Ketjenker carbon black are preferable as the light-shielding substance having an antistatic effect, which is expensive. If necessary, it is also desirable to mix the former and the latter according to the required characteristics. Although there are various forms of blending the light-shielding substance with the polyethylene-based polymer as described above, the masterbatch method is preferable in terms of cost, prevention of contamination of the workplace, and the like. Japanese Patent Publication No. 40-2
6196 discloses a method of dispersing a carbon black in a solution of a polymer dissolved in an organic solvent to prepare a polymer-carbon black masterbatch.
362 describes a method of dispersing carbon black in polyethylene to form a masterbatch.

The masterbatch method in which the carbon black used in the present invention is blended with a polyethylene-based polymer is not particularly limited to the following method.

First, a master batch is prepared by mixing LDPE (high-pressure low density polyethylene) with carbon black at a high concentration of 2% or more, generally 10% or more. This masterbatch is weighed so that the amount of carbon black in the final product becomes a predetermined value, and mixed with L-LDPE.

Two advantages can be recognized with this method. First, this method is easier to mix and disperse than to directly mix carbon black with L-LDPE, resulting in cost reduction and improved fish eye.

Second, LDPE and L-LDP rather than L-LDPE alone
The mixed system of E is superior in processability when producing a film. L-LDPE may be used as a resin for a masterbatch in order to reduce the cost of mixing carbon black. In the present invention, the resin for masterbatch has M.D. I. A polyolefin resin having a high viscosity is desirable in terms of uniform mixing. The same applies when other light-shielding substances are used.

Melt tension and flow characteristics are major problems of L-LDPE, and it has been said that the film production requires more energy than conventional polyethylene and often requires modification or even new installation of an inflation molding machine. In this regard, for example, Japanese Patent Laid-Open No. 55-11763.
8 discloses a method of changing the screw structure for reducing the load on the screw and reducing the heat generation due to rotation.

According to the above masterbatch method, when 5% or more of LDPE is contained, such modification is not necessary and the existing T-die or inflation molding machine can be used as it is. The smaller the amount, the better. However, when the amount of LDPE is larger than the amount of L-LDPE, the effect of improving the strength by carbon black does not sufficiently appear, and the amount of L-LDPE in all polyethylene-based polymers is large. Needs 45% or more,
It is preferably 50% or more, and particularly preferably 60% or more. The workability can be improved only by blending LDPE with L-LDPE, but the bubble stability is further improved due to the positive effect of adding the light-shielding substance.

On the other hand, the polymer blend system is excellent in physical properties, and in particular, the tear strength, heat seal strength and gelbotest strength are remarkably improved. The L-LDPE film layer may contain various known antistatic agents, slip agents, etc. in addition to the light-shielding substance.

The photographic light-sensitive material means a photographic light-sensitive material such as a silver halide photographic light-sensitive material, a diazo photographic light-sensitive material, a self-developing photographic light-sensitive material and a diffusion transfer type photographic light-sensitive material.

When the packaging material for a photographic light-sensitive material of the present invention is applied to the above-mentioned photographic light-sensitive material, a single flat bag, a double flat bag, a square bottom bag, a freestanding bag, a single gusset bag, a double gusset bag, a film sheet, It is possible to use any known form such as sticking inside a moisture-proof box or leader paper.

The product of the present invention has the flexible sheet 1 on the outside and the light-shielding layer 6 on one side, and is filled with the product photographic light-sensitive material, or various bags are formed, and the photographic light-sensitive material C is wrapped in the bag in order to completely shield light. good. The bag-making method is a conventionally known plastic film sealing method such as heat sealing, impulse sealing, ultrasonic sealing, or high-frequency sealing depending on the properties of the laminated film used. In addition, an appropriate adhesive,
It is also possible to make a bag using an adhesive or the like.

Preferred embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show the basic constitution of the laminate as the packaging material of the present invention, and FIG. 3 shows the basic constitution of the laminate of the reference example.

FIG. 1 shows a space 8 formed by an adhesive layer 1 in which a thermoplastic resin film layer 2'a containing a light-shielding substance is provided on the side in contact with a photographic light-sensitive material in the same vertical direction in the form of vertical stripes with continuous constant gaps. Is a laminated body in which another thermoplastic resin film layer 2a containing a light-shielding substance is laminated so that

FIG. 2 is a laminate in which the width, the gap and the thickness of the adhesive layer in FIG. 1 are different (the volume of the space 8 is also different) and the thermoplastic resin film layer which is not the photosensitive material side does not contain the light shielding material. It is an example of the body.

FIG. 3 shows a thermoplastic resin film layer containing two carbon blacks in the horizontal direction instead of the vertical streak-like adhesive layer provided with gaps which are continuous in the vertical direction and discontinuous in the horizontal direction in FIG. It is a laminated body in which a thermoplastic resin film layer is melted by using a continuous rotary heat sealer or the like without using an adhesive and laminated by an adhesive layer prepared.

4 to 8 are sectional views showing typical applications of the present invention.

FIG. 4 shows a laminated body using a metal thin film processed thermoplastic resin film layer 2 ″ having a light shielding property in which a metal thin film 2b is applied instead of 2a in FIG.

FIG. 5 shows a laminated body in which a metal foil 3a is laminated with an adhesive layer 4 on 2'instead of 2'a in FIG. 1 so as to have a light shielding property.

FIG. 6 shows a laminated structure in which a heat-sealing layer 5a containing a light-shielding substance is directly laminated on the side of the thermoplastic resin film layer 2'containing no light-shielding substance in contact with the photographic material, instead of 2'a in FIG. It is the body.

FIG. 7 shows an adhesive layer 4 on 2 provided in place of 2a in FIG.
Is a laminated body in which the flexible sheet layers 7 are laminated.

FIG. 8 shows that, instead of 2'a in FIG. 1, a heat-sealable heat-seal layer 6a separately formed by an adhesive layer 4 is laminated on 2 ', and a flexible sheet layer 7 is formed by the adhesive layer 4 instead of 2a. Is a laminated body in which

FIG. 9 shows a typical example of a conventional packaging material, which is an LDPE film 2'a containing 50% by weight and containing 3% by weight of carbon black, and an LPE adhesive layer 4 having a thickness of 15 μm on the outside in contact with the photographic material. The aluminum foil 3a having a thickness of 7 μm is laminated and the LDPE adhesive layer 4 having a thickness of 15 μm is used to form 35 g / m ³
Laminated bleached kraft paper 7 with a thickness of 45 μm, and further 1
It is a laminated body in which LDPE films 2a having a thickness of 50 μm and containing 3% by weight of carbon black in which polyisobutylene is added by an LDPE adhesive layer 4 of 5 μm are laminated.

FIG. 10 is a partially cutaway perspective view of the present invention. Fixed interval l
_{1, l 2, l 3,} l 4, l 5 in the longitudinal direction by the adhesive layer 1 of the continuous Hosohaba and two thermoplastic resin films 2a 2 '
A is laminated, and a space 8 is formed between the adhesive layers.

11 and 12 show a typical example of a single flat bag.

13 and 14 show a double-layered structure of an outer sheet and an inner sheet.
A representative example of a heavy bag is shown below. The present invention is not limited to the above representative examples, and any known bag type and layer structure can be used.

FIG. 15 shows an example of an apparatus for providing a narrow strip adhesive layer which is continuous in the vertical direction and discontinuous in the horizontal direction.
_The molten resin is extruded from the pores h provided in ₁ , 1, ₂ , ₃ , ₄ , and ₅ (see FIG. 10). Further, H in the drawing indicates a cross section of the fine pore h.

Example 1 A high-pressure low-density polyethylene film containing 3% by weight of carbon black having a thickness of 70 μm as 2′a in the layer structure shown in FIG. 1 is continuous in the longitudinal direction and discontinuous in the lateral direction. The gap is 5
cm, thickness 13 μm, width 0.3 mm, thin vertical stripe-shaped adhesive layer 1 made of molten high-pressure low-density polyethylene resin was extruded from a hole provided in a 5 cm gap specially attached to a T-die and applied. Use one. As 2a, a layer having the same composition as 2'a and having a thickness of 50 μm is used.
Table 1 shows the results of comparing the characteristics with the conventional product by making a laminated body that is not completely integrated by the space 8 and is laminated.

Example 2 With the same layer structure as in Example 1, 3% by weight of carbon black having the same thickness as 2a and 2'a and a thickness of 50 μm, 4.5% by weight of high pressure low density polyethylene and 4.5% by weight of low pressure linear low density polyethylene (L- LDPE) A laminate using an L-LDPE film layer made of a resin composition of 92.5% by weight was prepared.

Example 3 Hi-Zex (density 0.96 g / cm ³ ) manufactured by Mitsui Petrochemical Co., Ltd. having the same layer structure as in Example 1 and containing 4.5% by weight of carbon black having the same thickness of 35 μm as 2a and 2′a is uniaxial. A laminated body was formed using the molecularly oriented film.

The conventional product compared with the product of the present invention is a laminate having the layer structure shown in FIG.

The various properties are summarized in Table 1. The above examples show representative examples of preferred embodiments as the packaging material for a photographic light-sensitive material of the present invention, but the present invention is not limited to the above and may be combined with other known materials. It is possible.

Raw materials used for packaging materials in Table 1 1) L-LDPE Mitsui Petrochemical's Ultozex 2020L M. I. 2.5 g / 10 min, density 0.923g / cm ³ 2) LDPE manufactured by Nippon Unicar Co., DFD-0111 M. I. 2.4 g / 10 minutes, density 0.923 g / cm ³ 3) Carbon black Furnace carbon black manufactured by Mitsubishi Kasei Average particle size 21 mμ The first evaluation is as follows.

◎ Very good ○ Excellent ● Within practical limit ▲ Problematic × Not practical The outline of the test method is shown in the right column of Table 1, but the detailed test method is as follows.

Thickness conforms to JIS-8118.

Tear strength According to JIS-P8116.

Impact drilling strength According to JIS-P8134.

Gelvo test strength Using a device according to the US military standard MIL-B131, the number of bends until pinholes are generated in the packaging material and it becomes impossible to secure the light shielding property, the larger the number, the stronger the strength.

Evaluation × Pinhole occurrence at 2 or more times ▲ Pinhole occurrence at 3 to 7 times ● Pinhole occurrence at 7 to 50 times ○ Pinhole occurrence at 51 to 100 times ◎ Pinhole occurrence at 101 times or more Shading property ASA sensitivity of 100 The photographic film is put in a bag using each packaging material, completely sealed, and then exposed to light of 80,000 lux for 1 hour, and the light-shielding property is detected and evaluated by the degree of fog of the photographic film.

[Brief description of drawings]

1 and 2 are sectional views showing a typical basic configuration of the present invention. FIG. 3 is a sectional view showing the basic structure of the laminated body of the reference example. 4 to 8 are sectional views showing typical application examples of the present invention. FIG. 9 is a sectional view of a conventional packaging material for a photographic light-sensitive material. FIG. 10 is a partially cutaway perspective view of the laminated body of FIG. FIG. 11 is a partial cutaway perspective view when a flat bag is formed using the laminate of the present invention. FIG. 12 is a sectional view showing a state in which a photographic light-sensitive material is completely hermetically packaged using the laminate of the present invention. FIG. 13 is a conceptual sectional view showing a packaging form of black and white or color roll-shaped photographic light-sensitive materials (photographic paper, movie film, printing film, indirect X-ray film, microfilm, etc.). FIG. 14 is a cross-sectional view in which the laminated body of the present invention is used as an inner paper, and another outer paper is used in combination to form a bag having a double structure, and the photographic light-sensitive material is hermetically packed in the bag. FIG. 15 shows an example of an apparatus for providing a vertical stripe adhesive layer which is continuous in the vertical direction and discontinuous in the horizontal direction shown in FIG. The symbols in the figure indicate the following. 1, 1a: Vertical narrow continuous vertical streak adhesive layer: Thermoplastic resin film layer 2or by heat sealing
Melt adhesive layer of 2a and 2'or 2'a, 2,2a ... Thermoplastic resin film layer, 2 ', 2'a ... Thermoplastic resin film layer on photographic photosensitive material side 2b ... Metal thin film layer, 2 " , 2 "a ... Thermoplastic resin film layer for metal thin film processing (one body), (eg metal vapor deposition, sputtering), 3a ... Metal foil, 4, 4a ... Adhesive layer applied to the entire surface of the conventional type, 5, 5a ... … Direct heat seal layer, 6,6a …… Separately molded heat seal film layer, 7,7a …… Flexible sheet layer, 8 …… Space, A …… Outer paper, B …… Inner paper, C …… Photographic photosensitive material, D: Sealed part's folded adhesive part (when using adhesive), E ... Sealed part's folded adhesive part (when tape is used), H, h ... 1, 1a hole, _{l 1,} l 2 ...... 1,1a of the gap S ...... Hitoshi Le or sealing portion with an adhesive or the like.

Claims (5)

[Claims] 1. A two-layer thermoplastic resin film layer is directly adhered by an extruded laminate adhesive layer containing a thermoplastic molten resin in a parallel linear shape running only in one direction or a parallel thin continuous strip shape, and A smooth laminate with a sliding angle of 25 degrees or less, including three layers laminated while maintaining voids in parts other than the adhesive layer, (1) The layer in contact with the photographic light-sensitive material is a light-shielding substance. To 0.5
A heat-sealable thermoplastic resin film layer containing ~ 15 wt%, (2) the adhesive layer has a thickness of 8 to 50 μm, a width of 0.1 to 15 mm, and a gap between the adhesive layers of 10 to 100 mm, (3) Any one or more layers of the entire laminate is a light-shielding layer containing a light-shielding substance, (4) the two-layer thermoplastic resin film layer has an elongation at break of 150% or more in the vertical direction and a horizontal direction. A packaging material for a photographic light-sensitive material, which has a thickness difference of 200% or more and a thickness difference of 50% or less. 2. The thermoplastic resin film layer on the side in contact with the photographic light-sensitive material contains 50% by weight or more of a polyolefin resin (including a copolymer of ethylene and a monomer other than the polyolefin resin). The packaging material for a photographic light-sensitive material according to the item. 3. A light-shielding substance in the laminate is 0.1 to 30 g / m ²
The packaging material for a photographic light-sensitive material according to claim 1 or 2. 4. The packaging material for a photographic light-sensitive material according to claim 3, wherein the light-shielding substance is various carbon blacks. 5. The low-pressure normal linear low-density polyethylene (L-LDPE) -based film containing 1 to 15% by weight of carbon black as the thermoplastic resin film layer on the side in contact with the photographic light-sensitive material, and the adhesive layer. , Width 0.1 ~ 5mm, spacing 10 ~ 80mm, thickness 8
~ 18μm, other thermoplastic resin film layer is the L-LD
The packaging material for a photographic light-sensitive material according to any one of claims 1 to 4, wherein the thickness difference from the PE-based film layer is 50% or less.