JPH0611524B2 - Packaging material for photosensitive materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a packaging suitable for packaging comparatively heavy articles such as various kinds of photographic light-sensitive materials, photosensitive materials, electronic parts, etc. It is about materials.

[Conventional technology]

In general, as a high-tech product, for example, a packaging material for a photosensitive material such as a photographic photosensitive material, in addition to completely blocking light, gas barrier properties, moisture resistance, physical strength (breaking strength, tearing strength, impact drilling strength, Gelbotest strength, abrasion strength, etc.), heat seal suitability (heat seal strength, cut seal suitability, hot tack property, foreign matter seal property, etc.), antistatic property, lubricity, low dust generation, etc. Is required.

The present inventor has conducted diligent research to improve a packaging material for a photosensitive material, and has already disclosed what has improved physical strength by combining two layers of uniaxially stretched film (JP-A-57-6754). .

Further, as shown in FIG. 12, in the three-layer laminated film obtained by laminating the uniaxial molecular orientation thermoplastic resin film layer 6a containing the light-shielding substance on both sides of the thermoplastic resin foam sheet layer 3, the foam sheet layer 3 Has a thickness of 0.3 to 2.0 mm and a foaming ratio of 5 to 50 times, and the bilayer uniaxial molecular orientation thermoplastic resin film layer 6a has molecular orientation axes intersecting at an angle of 30 degrees or more. As described above, the thickness of the laminated film thermally fused and bonded to both surfaces of the foamed sheet layer 3 with or without the adhesive layers 4 and 4 is 40 to 85% of the theoretical sum of each layer (residual thickness We have already disclosed a laminated film which has a high impact puncture strength and a gelvotest strength compressed to a high taste ratio and has a small curling, which is very excellent as a packaging material for heavy objects in particular (Japanese Patent Laid-Open Publication No. Sho.
59-201848 publication).

[Problems to be Solved by the Invention]

However, the packaging material disclosed in Japanese Patent Laid-Open No. 56-6754 has insufficient heat-sealing suitability, is likely to cause curling, and has a large variation in physical properties due to a change in thickness of the adhesive layer.

On the other hand, the packaging material disclosed in JP-A-59-201848 is
It has excellent tear strength and impact puncture strength, and also has impact resistance, but because it uses a uniaxial molecular orientation thermoplastic resin film with almost the same softening point on the front and back, poor heat sealing suitability and low sealing strength. There was a flaw. It was also a packaging material that was prone to static electricity.

As described above, in conventional packaging materials, heat sealing suitability,
Antistatic property, Laminating suitability, Moisture proofing property, Bag making suitability, Packaging workability, Gas barrier property, Appearance (commercial value), Physical strength,
It is disadvantageous in that it has heat resistance under sunlight, front / back distinction in a dark room, interlayer peel strength, etc., and is expensive.

The present invention solves the above problems, has a beautiful appearance, high commercial value, large physical strength, good bag making suitability, heat retention, moisture resistance, gas barrier property, impact perforation strength, antistatic property, and burst strength. The purpose is to provide excellent and inexpensive packaging materials.

In particular, it is an object of the present invention to provide a packaging material suitable for packaging a roll-shaped or sheet-shaped photographic light-sensitive material which requires 100% guarantee of light-shielding property, moisture-proof property and gas barrier property.

[Means for Solving the Problems]

The present invention has been achieved by using a thermoplastic resin foam sheet layer and a metal layer in which a flexible sheet layer is arranged in combination to achieve the above object.

That is, the packaging material for a photosensitive material of the present invention comprises a thermoplastic resin foam sheet layer, a metal layer laminated on both sides of the thermoplastic resin foam sheet layer, and a flexible sheet layer laminated outside the metal layer. It is characterized by having.

The thermoplastic resin foam sheet layer used in the present invention is, for example, various polyethylene resins and various polypropylene resins, polyolefin resins such as polybutene resin, or ethylene-propylene copolymer resin, ethylene such as ethylene-butene copolymer resin. -Ethylene-based copolymer resins such as α-olefin copolymer resins, ethylene-vinyl acetate copolymer resins, ethylene-acrylic ester copolymer resins, and ethylene-based copolymers such as chlorinated polyethylene resins Resin, copolymer resin containing propylene as a main component, or polystyrene resin, polyester resin,
Polyamide resin, etc., one or more kinds of mixed resin, polyurethane, natural heat rubber (sponge-like one made from undiluted latex of rubber), synthetic rubber such as SBR, etc. are formed into a foam sheet using a foaming agent. It was formed.

Of these, the preferred thermoplastic resin foam sheet layer to which the present invention can be effectively applied is substantially polystyrene resin,
Various high-density, medium-density, and low-density polyethylene resins, linear low-density polyethylene (L-LDPE), resin polypropylene resin, propylene-ethylene copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-acrylic acid It is a thermoplastic resin foamed sheet layer containing an ester copolymer resin as a main component.

In particular, expanded polystyrene sheet (expanded polystyrene paper) and expanded polyethylene sheet are preferable in terms of cost and physical properties.

The thermoplastic resin also includes modified resin, crosslinked resin, radiation irradiation resin and the like.

The expansion ratio of the thermoplastic resin foamed sheet layer is selected according to the intended use of the product because it has a great influence on cushioning properties, slip characteristics and mechanical strength, but it is in the range of 2 to 50 times. When it exceeds 50 times, the strength of the thermoplastic resin foam sheet layer itself is largely reduced, and when laminated with another film, it causes delamination. If it is less than 2 times, the impact resistance, particularly the gel votest strength, will be lowered, and the other properties will not lose the effect as the thermoplastic resin foam sheet layer, and will be close to a general film at a high cost.

The thickness of the thermoplastic resin foam sheet layer is preferably 0.2 to 2 mm.

If it is less than 0.2 mm, the same problem as when the expansion ratio is less than 2 times occurs, and if it exceeds 2 mm, the same problem as when the expansion ratio exceeds 50 times occurs, and when laminating Various problems occur during bag manufacturing (poor heat sealability, poor workability due to bulkiness, etc.).

The metal layer used in the present invention is composed of a metal foil made of a single metal or the like, or a metal thin film formed on a flexible sheet by vacuum deposition or the like.

The metal foil is made of aluminum foil having a thickness of 5 to 50 μm, tin foil, lead foil, iron foil, or other metal foil, galvanized thin-layer steel sheet, and a thin film of ionized metal formed by electrolysis.

The metal thin film is provided on the flexible sheet layer by a conventionally known thin film forming method such as a vacuum evaporation method, a sputtering method, an ion plating method and an electron beam evaporation method.

For the metal thin film, Al, Sn, Zn, Co, Cr, Ni, F
Although simple metals such as e and Cu, alloys, and other metals capable of forming a thin film can all be used, aluminum (Al) is most suitable in terms of cost and workability.

The metal thin film preferably has a thickness of 50 to 1200 Å from the viewpoints of physical strength, light-shielding property, antistatic property and moisture-proof property, ensuring gas barrier property, cost and quality. When the thickness is less than 50Å, the moisture resistance, gas barrier property, light shielding property and antistatic property are inferior, and it is difficult to reduce the charge generated on both layers of the metal thin film.
Also, if the thickness exceeds 1200 Å, antistatic property, moisture resistance,
Although the light-shielding property can be secured, there are problems in cost and in the vacuum deposition method and the like in that the flexible sheet layer is deteriorated by heating, and the physical strength of the resulting laminated film is reduced as a result of heat shrinkage. 80 for normal use in the case of aluminum vapor deposition film
~ 800Å is preferable, more preferably 100 ~ 600
It is Å.

The flexible sheet layer used in the present invention protects the metal layer and improves physical strength and the like.

This flexible sheet layer may be provided separately from the metal layer as long as it is laminated on the outer side of the metal layer, or a flexible sheet layer on which a metal thin film is formed may be applied.

As the flexible sheet layer, a known thermoplastic resin film such as various polyethylene resins, ethylene copolymer resins, polypropylene resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyamide resins, polycarbonate resins, polystyrene resins, polyester resins, etc. In addition to films and films of modified resins thereof, there are cellulose acetate film, cellophane, polyvinyl alcohol and the like.

Particularly preferred as the product of the present invention is a flexible sheet layer on which a metal thin film is formed, which has a thickness of 8 to 40 in order to reduce the thickness of the packaging material, reduce costs, and secure physical strength.
Various μm synthetic resin coated papers, synthetic papers, cellophane, thermoplastic resin films and the like are used. Most preferred is a uniaxially or biaxially molecularly oriented polypropylene film, polyester film, high density polyethylene film, polyamide film, polystyrene film having a thickness of 8 to 30 μm, and a mixed resin film of any one of these resins and another resin. Is. As the polypropylene film, an unstretched film is preferable because it has a large physical strength and is inexpensive. Also,
An ultrathin reinforced film in which a blow ratio is increased by using a high-density polyethylene resin is particularly preferable because it has a large physical strength and is inexpensive.

The uniaxial molecular orientation thermoplastic resin film layer is a film in which the molecules are uniaxially oriented. A uniaxially stretched thermoplastic resin film layer is a typical uniaxially oriented thermoplastic resin film layer. It can also be molded using a device for forcibly orienting molecules in a uniaxial direction. Such a uniaxial molecular orientation thermoplastic resin film layer means all films in which the difference in tear strength between the molecular orientation axis and the orthogonal direction axis is twice or more. In particular, a uniaxially stretched thermoplastic resin film layer having a stretch ratio of 3 or more is preferable. A non-stretched film that is not stretched, and a single-layer or multi-layer blown film using a special resin composition can be used as an inexpensive uniaxial molecular orientation thermoplastic resin film layer.

The uniaxial molecular orientation direction may be horizontal, vertical or oblique, and the uniaxial molecular oriented thermoplastic resin film layer is preferably a uniaxial molecular oriented HDPE resin film having a thickness of 10 μm or more.

The most typical example of the multiaxial molecular orientation thermoplastic resin film layer is a biaxially stretched thermoplastic resin film layer. The biaxially stretched thermoplastic resin film layer may be formed vertically and horizontally separately, or may be formed simultaneously in both directions.

The biaxially stretched thermoplastic resin film layer is a film stretched 1.5 times or more in both length and width.

It is preferable to include a light-shielding substance in one or more of the laminated films. This light-shielding substance means a substance that can be kneaded or dispersed in each layer and that does not transmit visible light, ultraviolet light, and the like.

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

It is preferable that the light-shielding substance is contained in an amount of 0.1 to 20.0% by weight.

If it is less than 0.1% by weight, the effect of adding a light-shielding substance (securing of light-shielding property, antistatic property, etc.) cannot be expected, and the cost is increased by the kneading cost.

If it exceeds 20.0% by weight, the physical strength of the polyethylene-based resin film, particularly the tear strength and impact puncture strength, deteriorates and the heat sealability deteriorates, making it difficult to put into practical use.

Carbon black is particularly important among the light-shielding substances.

Carbon black mainly secures a light-shielding property and improves physical strength and conductivity.

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

Furnace carbon black is preferable for the purpose of improving the light-shielding property, cost, and physical properties of the packaging material for a photosensitive substance of the present invention, and acetylene-carbon black, Ketjen carbon black, graphite as the light-shielding substance having an antistatic effect although it is expensive. Is preferred. If necessary, it is also preferable to mix the former and the latter according to the required characteristics. However, Ketjen carbon black is liable to cause fog, and it may be necessary to select raw materials and take measures using a photographic emulsion.

Although there are various forms of blending the light-shielding substance, the masterbatch method and the die color granulation method are preferable from the viewpoints of cost reduction, prevention of contamination of the workplace, and the like.

For laminating the thermoplastic resin foam sheet layer, the metal layer and the flexible sheet layer, for example, a thermal bonding method (a hot plate bonding method, a flame treatment bonding method, a hot air heating bonding method, an impulse bonding method, an ultrasonic bonding method). A method using an adhesive (a wet laminating method, a dry laminating method, a hot melt laminating method, an extrusion laminating method, a co-extrusion extrusion laminating method) or the like is used.

As typical adhesives, various polyethylene resins,
Polyolefin resin, polybutene resin and other polyolefin type thermoplastic resin hot melt adhesive, ethylene-propylene copolymer resin, L-LDPE resin ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer resin and other ethylene copolymer Thermoplastic resin hot-melt adhesives such as polymer resins, ethylene-acrylic acid copolymer resins, and ionomer resins, and other hot-melt rubber adhesives are available. As the solution adhesive, there is an adhesive for wet lamination, which is an emulsion or latex adhesive.

Typical examples of emulsion adhesives are polyvinyl acetate resin, vinyl acetate-ethylene copolymer resin, vinyl acetate resin and acrylic ester copolymer resin, vinyl acetate resin and maleic ester copolymer resin, acrylic acid. There are emulsions such as copolymer resins and ethylene-acrylic acid copolymer resins.

Typical examples of the latex type adhesive include rubber latex such as natural rubber, styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR) and chloroprene rubber (CR).

Further, as the adhesive for dry lamination, there is a polyurethane adhesive or the like. Other known adhesives such as hot-melt adhesives, pressure-sensitive adhesives, and heat-sensitive adhesives blended with paraffin wax, microcrystalline wax, ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer resin, etc. You can also

A preferred representative example of the polyolefin resin adhesive for extrusion lamination is, more specifically,
In addition to various polyethylene resins, polypropylene resins, polyolefin resins such as polybutylene resins and ethylene copolymer (EVA, EEA, EMA, EAA, etc.) resins, L-
Like LDPE resin, some other monomers (α-olefin) are copolymerized in addition to ethylene, Surlyn of Dupont, ionomer resin (ion copolymer resin) such as Himilan of Mitsui Polychemicals, and various Ethylene-modified resins having improved adhesiveness, such as ADMER, which is an adhesive polyolefin resin manufactured by Mitsui Petrochemical Co., Ltd.

The packaging material for a photosensitive substance of the present invention can be used for packaging various products, among them, a photographic photosensitive material, a food product, a pharmaceutical product,
It is suitable for packaging photosensitive substances such as chemical substances.

In particular, silver halide photographic light-sensitive materials, diazo photographic light-sensitive materials, photosensitive resins, self-developing photographic light-sensitive materials, diffusion transfer photographic light-sensitive materials, photosensitive heat-sensitive materials, etc., whose quality is destroyed by slight gas, light and humidity. Most suitable for photographic materials.

When the packaging material of the present invention is applied to, for example, the above-mentioned photographic light-sensitive material, a single flat bag, a double flat bag, a self-supporting bag, a single gusset bag, a double gusset bag, a laminated film, and a moisture-proof box inside,
It can be used in all known forms such as inside a light-room loading light-shielding magazine and leader paper.

The bag-making method is a conventionally known plastic film sealing method such as heat sealing, fusing sealing, impulse sealing, ultrasonic sealing, or high-frequency sealing depending on the properties of the laminated film used. Note that it is also possible to make a bag using an appropriate adhesive or pressure-sensitive adhesive.

[Action]

In the photosensitive material packaging material of the present invention, by disposing the thermoplastic resin foam sheet layer in the middle, the impact destructive force applied to the front surface or the back surface is consumed as the destructive energy of the flexible sheet layer and the metal layer on each one side, Prevent the propagation of destruction. Further, curling is prevented by absorbing different stresses applied to the front surface or the back surface, and tear strength, impact drilling strength, gel botest strength, etc. are made strong.

By disposing the metal layers on both sides of the thermoplastic resin foamed sheet layer, moisture resistance, gas barrier property and antistatic property are secured even if one metal layer is destroyed.

By placing the flexible sheet layer on the surface of the metal layer, it protects the metal layer and improves the Young's modulus, preventing pinholes and tears that occur at the corners even when packaging products with sharp edges and preventing moisture. The property is greatly improved as compared with the metal layer alone.

〔Example〕

Embodiments of the packaging material for photosensitive material of the present invention are shown in FIGS.
It will be described with reference to the drawings.

1 to 7 are partial cross-sectional views showing the layer structure of the packaging material for photosensitive material.

The packaging material for a photosensitive material shown in FIG. 1 is an aluminum vacuum deposition layer 2 of an aluminum vacuum deposition thermoplastic resin film 10 obtained by vacuum deposition of an aluminum vacuum deposition layer 2 as a metal layer on a thermoplastic resin film layer 1 as a flexible sheet layer. And a light-shielding substance as a flexible sheet layer and L
-Aluminum vacuum vapor deposition light shielding polyolefin resin film layer 11a formed by vacuum vapor deposition of aluminum vacuum vapor deposition layer 2 as a metal layer on light shielding polyolefin resin film layer 5a containing an LDPE resin. It is configured by laminating thermoplastic resin foam sheet layers 3 via layers 4 and 4.

The packaging material for a photosensitive material of FIG. 2 is an aluminum vacuum vapor-deposited uniaxial molecular orientation thermoplastic resin film layer obtained by vacuum vapor deposition of an aluminum vacuum vapor deposition layer 2 as a metal layer on a uniaxial molecular orientation thermoplastic resin film layer 6 as a flexible sheet layer. The thermoplastic resin foam sheet layer 3 is laminated between the aluminum vacuum vapor deposition layer 2 of 12 and the aluminum vacuum vapor deposition layer 2 of the aluminum vacuum vapor deposition light shielding polyolefin resin film layer 11a via the adhesive layers 4 and 4. It is configured.

The packaging material for the photosensitive material shown in FIG. 3 is the aluminum vacuum deposition layer 2 of the aluminum vacuum deposition thermoplastic resin film layer 10.
And the metal foil layer 14 as a metal layer, between the adhesive layer 4,
4, a thermoplastic resin foam sheet layer 3 is laminated via the adhesive layer 4, and a light-shielding polyolefin resin film layer as a flexible sheet layer on the outside of the metal foil layer 14 via the adhesive layer 4.
It is configured by stacking 5a.

The photosensitive material packaging material of FIG. 4 is obtained by laminating a light shielding polyolefin resin film layer 5a as a flexible sheet layer with a metal foil layer 14 as a metal layer via an adhesive layer 4 and the metal foil layer 14 and a flexible layer. Aluminum vacuum deposition multiaxial molecular orientation (including stretching) thermoplastic resin film layer 13 in which multiaxial molecular orientation (including stretching) thermoplastic resin film layer 7 as a sheet layer is vacuum-deposited with aluminum vacuum deposition 2 as a metal layer The thermoplastic resin foam sheet layer 3 is laminated between the aluminum vacuum deposition layer 2 and the aluminum vacuum deposition layer 2 via the adhesive layers 4 and 4.

The photosensitive material packaging material shown in FIG. 5 is obtained by coating the aluminum vacuum deposition layer 2 as a metal layer of the aluminum vacuum deposition multiaxial molecular orientation thermoplastic resin film layer 13 with an extremely thin coating layer 8 as a flexible sheet, Aluminum vacuum vapor deposition multiaxial molecular orientation thermoplastic resin film layer 13 of multiaxial molecular orientation thermoplastic resin film layer 7 and aluminum vacuum vapor deposition multiaxial molecular orientation thermoplastic resin film layer 13 of multiaxial molecular orientation thermoplastic resin film layer 7 Between the adhesive layers 4, 4
The thermoplastic resin foam sheet layer 3 is laminated via the above, and a light-shielding polyolefin resin extrusion laminate film layer 9a as a flexible sheet layer is laminated outside the aluminum vacuum deposition layer 2.

The packaging material for the photosensitive material shown in FIG. 6 includes aluminum vacuum vapor deposition multiaxial molecular orientation (including stretching) aluminum vacuum vapor deposition layer 2 of the thermoplastic resin film layer 13 and aluminum vacuum vapor multiaxial molecular orientation (including stretching) heat. A thermoplastic resin foam sheet layer 3 is laminated between the plastic film layer 13 and the multiaxial molecular orientation thermoplastic resin film layer 7, and further, a light-shielding polyolefin resin as a flexible sheet layer is provided outside the aluminum vacuum deposition layer 2. The film layers 5a are laminated.

The packaging material for the photosensitive material shown in FIG. 7 is the aluminum vacuum deposition layer 2 of the aluminum vacuum deposition multiaxial molecular orientation thermoplastic resin film layer 13 and the aluminum vacuum deposition layer 2 of the aluminum vacuum deposition light-shielding polyolefin resin film layer 11a.
And the thermoplastic resin foam sheet layer 3 are laminated via the molten thermoplastic foam adhesive layers 15, 15 obtained by melting the surface of the thermoplastic resin foam sheet layer.

FIG. 8 to FIG. 11 are partial cross-sectional views showing the layer structure of the comparative packaging material for photosensitive material.

The packaging material for the photosensitive material of the comparative product of FIG. 8 is the aluminum vacuum deposition layer 2 of the aluminum vacuum deposition multiaxial molecular orientation (including stretching) thermoplastic resin film layer 13 and the light-shielding heat containing no L-LDPE resin. The light-shielding thermoplastic resin film layer 1a of the light-shielding multilayer coextrusion film layer 16a of the plastic resin film layer 1a and the light-shielding polyolefin resin film layer 5a,
It is configured by laminating with an adhesive layer 4.

The packaging material for the photosensitive material of the comparative product of FIG. 9 includes the aluminum vacuum deposition layer 2 of the aluminum vacuum deposition multiaxial molecular orientation thermoplastic resin film layer 13, the light shielding polyolefin resin film layer 5a, and the adhesive layer 4 interposed therebetween. It is configured by stacking.

The packaging material for the photosensitive material of the comparative product of FIG. 10 is an aluminum vacuum deposition multiaxial molecular orientation thermoplastic resin film layer 13 and a light-shielding polyolefin resin extrusion laminate film layer 9a, which are directly laminated by an extrusion lamination method. Is configured.

The comparative photosensitive material packaging material shown in FIG. 11 comprises a uniaxial molecular orientation thermoplastic resin film layer 6 and an aluminum vacuum deposition layer 2
An aluminum vacuum vapor deposition layer 2 of an aluminum vacuum vapor deposition uniaxial molecular orientation thermoplastic resin film layer 12 formed by vapor deposition of
The light-shielding polyolefin resin film layer 5a is attached to the adhesive layer 4
It is configured to be laminated via.

Next, the experimental results comparing the characteristics of the product I of the present invention, the comparative products I and II, and the conventional product I will be described.

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

As the thermoplastic resin foam sheet layer 3, a cross-linked polyethylene resin foam sheet layer having a thickness of 500 μm and an expansion ratio of 30 was used.

The multiaxial molecular orientation thermoplastic resin film layer 7 has a thickness of 12 μm.
The aluminum vacuum-deposited layer 2 was made to have a thickness of 400Å by using the biaxially stretched polyester resin film.

The light-shielding polyolefin resin film layer 5a has an MI of 2.
Ethylene-4-methylpentene-1 copolymer resin (1 g / 10 min, density 0.920 g / cm ³ (Ultzex 2020)
L, manufactured by Mitsui Petrochemical Co., Ltd.) and 97% by weight of furnace carbon black, and a light-shielding L-LDPE resin film having a thickness of 80 μm was used.

The polyaxial molecular orientation thermoplastic resin film layer 7 on the light-shielding polyolefin resin film layer 5a side was a biaxially stretched polyamide resin film having a thickness of 15 μm, and the aluminum vacuum deposition layer 2 had a thickness of 400Å.

The adhesive layer 4 is an LDPE resin extruder with a thickness of 15 μm.
A John Laminate adhesive layer was used.

Comparative product I The layer structure of the comparative product I corresponds to the layer structure of FIG.

The aluminum vacuum-deposited multiaxial molecular orientation thermoplastic resin film layer 13 is the same aluminum vacuum-deposited biaxially stretched polyester resin film as the product I of the present invention.

The light-shielding polyolefin resin film layer 5a comprises LDPE resin 5% by weight, furnace carbon black 3% by weight, M
I: 2.1 g / 10 min, density: 0.920 g / cm ³ ethylene-4-methylenepentene-1 copolymer resin (Ultzex 2020L, manufactured by Mitsui Petrochemical Co., Ltd.) 92% by weight, thick 40 μm.

The light-shielding thermoplastic resin film layer 10a is made of furnace carbon black 3% by weight, MI 0.9 g / 10 minutes, density 0.9.
It was composed of 97% by weight of 54 g / cm ³ of HDPE resin (Hi-Zex 3300F, manufactured by Mitsui Petrochemical Co., Ltd.) and had a thickness of 40 μm.

Comparative product II The layer structure of the comparative product II corresponds to the layer structure of FIG.

Aluminum vacuum evaporation multi-axis molecular orientation thermal evaporation film layer 13
Is the same aluminum vacuum-deposited biaxially stretched polyester resin film as the product I of the present invention.

Light-shielding polyolefin resin extrusion laminate film layer 9a is made of carbon black 3% by weight, MI7
It was made of 97% by weight of an ethylene-4-methylpentene-1 copolymer resin (Ultzex 2080C, manufactured by Mitsui Petrochemical Co., Ltd.) having a density of 0.920 g / cm ³ and a thickness of 80 μm.

Conventional product I The layer structure of the conventional product I corresponds to the layer structure of FIG.

The thermoplastic resin foam sheet layer 3 has a thickness of 1 mm,
It is the same as the product I of the present invention. Light-shielding uniaxial molecular orientation HD As the thermoplastic resin film layer 6a, the thickness is 35 μm and contains 4.5% by weight of carbon black.
A PE resin film was used. The adhesive layer 4 is L having a thickness of 15 μm
A DPE resin extrusion-laminate adhesive layer was used.

The experimental results are shown in Table 1.

The evaluation is as follows.

◎… very good 〇… excellent ●… possible (within practical limits) ▲… problem (needs improvement) ×… impossible practical ××… outside problem * A curling A laminated film to be tested with a diameter of 10 cm 1kg in the atmosphere of temperature 20 ℃, humidity 65% RH
After being left under the load plate for 24 hours, each circular test sample was left unloaded on the flat plate for 24 hours in the atmosphere of the above conditions, and then evaluated in the curling state. * B Bag-making suitability Heat sealing method The heat seal suitability when making a sealed bag, the strength of the sealed part, the appearance, pinhole prevention, front / back distinctiveness, antistatic property, delamination strength, etc. are comprehensively evaluated. * C peeling electrification voltage An endless belt with a width of 35 mm and a length of 1350 mm was made, and this belt was sent between a SUS roller (stainless steel) with a load of 500 g and a SUS roller at a speed of 12 m / min using a charging voltage generator manufactured by Shinto Kagaku Co., Ltd. A value measured by a voltmeter when the peeling electrification voltage when it is opened.

* D Heat resistance Judgment of the surface temperature rise of the packaging material after being left in sunlight (80,000 lux) for 3 hours and measured with a thermistor * E Heat sealing suitability Hot tack, foreign matter sealing, heat Seal strength,
Judged from total heat sealing suitability such as heat sealing strength over time, allowable temperature range for heat sealing, etc. * F heat retention The temperature inside the sealed bag was increased by using each packaging material after leaving it in the sunlight (80,000 lux) for 3 hours. Judgment made by measuring with a thermistor [Effect of the invention] Since the present invention is configured as described above, it has excellent appearance, moisture-proof property, light-shielding property, gas barrier property, antistatic property, tear strength, bag breaking strength, impact It has excellent physical strength such as drilling strength and gelbotest strength, no curling, good heat sealability, good bag making suitability, and excellent heat retention and heat insulation.

[Brief description of drawings]

1 to 7 are partial cross-sectional views showing the layer structure of an embodiment of the packaging material for photosensitive material of the present invention. FIG. 8 to FIG. 11 are partial cross-sectional views showing the layer structure of the packaging material for the photosensitive material of the comparative product. FIG. 12 is a partial cross-sectional view showing the layer structure of a conventional packaging material for photosensitive substances. 1, 1a …… thermoplastic resin film layer 2 …… aluminum vacuum deposition layer 3, 3a …… thermoplastic resin foam sheet layer 4, 4a …… adhesive layer 5, 5a …… polyolefin resin film layer 6, 6a …… Uniaxial molecular orientation thermoplastic resin film layer 7, 7a ... Multiaxial molecular orientation thermoplastic resin film layer 8, 8a ... Ultra thin coating coat layer 10, 10a ... Aluminum vacuum-deposited thermoplastic resin film layer 11, 11a ... Aluminum vacuum deposition light-shielding polyolefin resin film layer 12, 12a Aluminum vacuum deposition uniaxial molecular orientation thermoplastic resin film layer 13, 13a Aluminum vacuum deposition multiaxial molecular orientation thermoplastic resin film layer 14 Metal foil layer 15 , 15a …… Adhesive layer for molten thermoplastic foam sheet 16, 16a …… Multi-layer coextrusion film layer

Claims (1)

[Claims] 1. A thermoplastic resin foam sheet layer, a metal layer laminated on both sides of the thermoplastic resin foam sheet layer, and a flexible sheet layer laminated outside the metal layer. Characteristic packaging material for photosensitive substances