JPH01251031A - Wrapping material for photographic sensitive substance - Google Patents

Abstract

PURPOSE:To improve the physical strength and the bag making aptitude, etc., of the wrapping material, and to inexpensively make the wrapping material by laminating a shading polyolefin resin film and a thermoplastic resin film which is subjected to a vacuum-deposition with aluminum and a molecular-orientation on the both surfaces of a foamed sheet composed of a thermoplastic resin, respectively. CONSTITUTION:A resin contg. one or more of various kinds of resins, such as a polystyrene resins, a high density, a middle density, a low density and a straight-chain and low density polyethylene resins is sheet-likely formed using a foaming agent. The wrapping material is constituted of the thermoplastic resin foamed sheet 5 and the shading polyolefin resin film 3a contg. the straight chain low density polyethylyne resin and a shading substance laminated on the one side surface of the sheet 5, and the thermoplastic resin film I which is subjected to the vacuum-deposition with the aluminum and the molecular-orientation and is laminated on the another surface of the sheet 5. And, the layer 2 of the resin film I vacuum-deposited with the aluminum is positioned on the side of the sheet 5. Thus, the wrapping material for the photosensitive material with the excellent physical strength and the bag making aptitude, etc., can be inexpensively obtd.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a packaging material suitable for packaging relatively heavy items such as movie roll films among various photographic materials, photosensitive substances, electronic parts, etc. It is related to.

[Prior Art] Packaging materials for photosensitive materials such as photographic materials generally have properties such as gas barrier properties, moisture proofing properties, physical strength (breaking strength, tearing strength, impact puncturing strength, etc.) in addition to completely blocking light.
gelbo test strength, abrasion strength, etc.), heat sealability (
Heat seal strength.

(cut sealability, hot tackability, contaminant sealability, etc.)
, antistatic properties, lubricity, low dust generation, flatness, and other properties are required.

The present inventor conducted extensive research to improve packaging materials for photosensitive materials, and discovered a material with improved physical strength by combining two layers of uniaxially stretched films (Japanese Patent Laid-Open No. 57-675
4) has already been disclosed.

Further, as shown in FIG. 12, in a three-layer laminated film formed by laminating uniaxially oriented thermoplastic resin film layers 8a containing a light-shielding substance on both sides of a thermoplastic resin foam sheet layer 5 with an adhesive layer 4, the sheet The thickness of the shaped foam is 0.3 to 2.
0ma+, and the expansion ratio is 5 to 50 times, and the two-layer uniaxially molecularly oriented film is made by applying heat melt adhesive layers to both sides of the foam so that the molecular orientation axes intersect at an angle of 30 degrees or more. Or, the thickness of the laminated film bonded by heat melting without intervening is 40 to 85% of the theoretical sum of each layer (residual thickness ratio)
A laminated film that is compressed into a material with high impact puncture strength, high gelbo test strength, and low curling, and is particularly excellent as a packaging material for heavy goods (Japanese Patent Application Laid-Open No. 59-201848
Publication No.) was disclosed.

[Problem to be solved by the invention]

However, the packaging material disclosed in JP-A-56-6754 lacks heat-sealing suitability, tends to cause curling, and also has a large physical strength fluctuation due to changes in the thickness of the adhesive layer. If the adhesive layer is too thin, delamination failure will occur, and if the adhesive layer is too thick, the notch effect will be lost and the adhesive will be in the same state as a single layer film, resulting in significantly lower tear strength and impact puncture strength. There were problems such as a decrease in

On the other hand, the packaging material disclosed in JP-A No. 59-201848 has excellent tear strength, impact puncture strength, and impact resistance, so it has been put into practical use as a reinforced light-shielding bag to replace metal cans. Since we use a uniaxially oriented thermoplastic resin film with almost the same softening point on the front and back sides,
Heat sealability was poor, sealing strength was low, and unless a heat-resistant film or Teflon tape was interposed between the laminated film and the heat sealer on the heat sealer side, it would melt and break, making it impossible to ensure light shielding and sealing properties. .

In addition, the conventional packaging materials mentioned above have heat-sealing properties, antistatic properties, lamination suitability, moisture proofing properties, packaging workability,
It had some drawbacks in gas barrier properties, appearance (commercial value), physical strength, heat resistance under sunlight, ability to distinguish between front and back in a dark room, strength to remove between eyebrows, etc., and was expensive.

The present invention solves the above problems and provides an inexpensive bag with excellent appearance, high physical strength, good suitability for bag making, moisture proofing, heat retention, gas barrier properties, impact puncturing strength, bursting strength, etc. Its purpose is to provide packaging materials for photosensitive materials.

In particular, photographic materials that lose their commercial value unless light-shielding, heat-retaining, moisture-proofing, and gas-barrier properties are always guaranteed 100%;
For example, we are developing an inexpensive packaging material for photosensitive materials that has the above properties suitable for photographic photosensitive materials in the form of rolls and sheets of various types of photographic paper and films, has excellent heat sealability, has high tear strength, and has excellent heat retention. is intended to provide.

[Means to solve the problem]

The present invention was made to achieve the above object, and was achieved by laminating a light-shielding polyolefin resin film and an aluminum vacuum-deposited molecularly oriented thermoplastic resin film on both sides of a thermoplastic resin foam sheet. be.

That is, the packaging material for photosensitive materials of the present invention comprises a thermoplastic resin foam sheet, a light-shielding polyolefin resin containing a linear low-density polyethylene resin and a light-shielding substance laminated on one side of the thermoplastic resin foam sheet. and an aluminum vacuum-deposited molecularly oriented thermoplastic resin film laminated on the other side of the thermoplastic resin foam sheet, wherein the aluminum vacuum-deposited layer of the aluminum vacuum-deposited molecularly oriented thermoplastic resin film is made of thermoplastic resin. It is characterized by being located on the foam sheet side.

The thermoplastic resin foam sheet used in the present invention includes polyolefin resins such as polystyrene resin, high-density, medium-density, low-density, and linear low-density polyethylene resins, polypropylene resin, polybutene resin, and ethylene-propylene resin. Polyolefin copolymer resins such as copolymer resins, ethylene-butene copolymer resins, ethylene-vinyl acetate copolymer resins, ethylene-acrylic acid ester copolymer resins, and chlorinated polyethylene resins that mainly contain ethylene A copolymer resin containing propylene as a main component, and a thermoplastic resin such as a polyester resin or a polyamide resin is formed into a sheet using a foaming agent.

Among these, foamed polystyrene sheets (foamed polystyrene paper) and foamed polyethylene sheets are preferred in terms of cost and characteristics.

Note that this thermoplastic resin also includes modified, crosslinked, and radiation irradiated resins.

The foaming ratio of a foam sheet is determined by its cushioning properties, sliding properties,
Since it has a large effect on mechanical strength, it is selected depending on the intended use of the product, but a range of 2 to 50 times is preferable. If it exceeds 50 times, the strength of the foam sheet itself will decrease significantly, and when laminated with other films, it will cause delamination. If it is less than 2 times, the impact resistance, especially the impact puncture strength and gelbo test strength, will decrease, and other properties will approach those of ordinary films without losing the effectiveness as a foam sheet and being expensive.

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

When the foaming ratio is less than 0.2, the same problem as when the expansion ratio is less than 2 times occurs, and when it exceeds 2 nm, the same problem as when the foaming ratio exceeds 50 times occurs. If the thickness exceeds 2 mm, it may cause disadvantages in heat sealability and handling during lamination and bag making.

The light-shielding polyolefin resin film laminated with the thermoplastic resin foam sheet used in the present invention contains at least linear low-density polyethylene (hereinafter referred to as L-LDPE) resin and carbon black. This L-LDPE resin is called a 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. The L-LDPE resin is preferably 3
97% by weight, particularly preferably 10 to 95% by weight.

L-LDPE resin is produced by adding ethylene with 4 to 13 carbon atoms, preferably 4 to 10 carbon atoms, butene-1, hexene-1,4-methylpentene-1, octene-1, or heptene by a low-pressure method or a high-pressure modification method. A copolymer made by copolymerizing α-olefins such as -1, etc., with a linear structure with short branches in a linear chain with an ethylene content of 85 to 99.5 mol%, and a density of 0.8
70-0.950g/c4, melt index 0.
4 to 20 g/10 minutes is preferable. Molecularly oriented and stretched materials can also be used.

Specific examples of L-LDPE resins by trade name include G Resin, TUFLIN, and NUC-FLX (UCC), Dowlex (Dow Chemical), Sflare (DuPont Canada), Marlex (Philips), NUC
Polyethylene-LL and TUFTHENE (Nippon Unicar), Neo-Zex and Ult-Zex (Mitsui Petrochemical)
, F-selen L (Jumin Chemical), Megasu Nilex (Japan Petrochemical), Idemitsu Polyethylene-L and MORETE
C (Idemitsu Petrochemical Co., Ltd.), Stamilex CD5M Co., Ltd.), etc.

Other resins used in combination with L-LDPE resin in the light-shielding polyolefin resin film include ethylene copolymer resin and/or polyethylene resin and/or polyethylene resin having a density of 0.910 or more.
Or various polypropylene resins are preferred.

Polyethylene resins include low density polyethylene (hereinafter referred to as LDPE) resin, medium density polyethylene (hereinafter referred to as MDPE) resin, and high density polyethylene (hereinafter referred to as HDPE) resin manufactured by various manufacturing methods. Ethylene copolymer resins include ethylene-vinyl acetate copolymer (hereinafter referred to as EVA) resin, ethylene-ethyl acrylate copolymer (
Typical examples include resins (hereinafter referred to as EEA).

The carbon black is mainly used to ensure light-shielding properties and to improve antioxidant properties, electrical conductivity, and physical strength. This carbon black is 0.05 to 1
Preferably, it is contained in an amount of 5.0% by weight.

If the concentration is less than 0.05%, it is necessary to further laminate another light-shielding layer in order to ensure light-shielding properties.

If it exceeds 15.0% by weight, the physical strength and heat sealability of the polyolefin resin film will decrease, leading to an increase in cost.

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

In the packaging material for photosensitive materials of the present invention, furnace carbon black is preferable for the purpose of improving light-shielding properties, cost, and physical properties, and examples of light-shielding substances that have an antistatic effect, although expensive, include acetylene carbon black, Ketchiene carbon black, and graphite. , surface-treated pigments, short metal fibers, carbon fibers, metal powders, etc. are preferred, and if necessary, it is also preferred to mix the former and the latter according to the required characteristics.

Ketchien carbon black fogs the photographic emulsion layer (F
OG) is likely to occur, and countermeasures may be necessary in selecting raw materials or using photographic emulsions.

The aluminum vacuum-deposited molecularly oriented thermoplastic resin film to be laminated with the thermoplastic resin foam sheet used in the present invention is
An aluminum vacuum-deposited layer is provided on a molecularly oriented thermoplastic resin film by vacuum deposition. As the molecularly oriented thermoplastic resin film, a polyester resin film, a polyamide resin film, a polystyrene resin film, a polyolefin resin film, or the like with -axis or biaxial molecular orientation (including stretching) is used.

The uniaxial molecularly oriented thermoplastic resin film layer used in the present invention is a film in which molecules are uniaxially oriented. As a typical uniaxially oriented film, a uniaxially stretched film can also be formed using an apparatus that forcibly orients molecules in a uniaxial direction. Such a molecularly oriented film refers to a film in which the difference in tear strength between the molecular orientation axis and the orthogonal axis is more than double. In particular, the stretching ratio is 3
A uniaxially stretched film that is at least twice that amount is preferable. A single-layer or multi-layer molecularly oriented blown film using a special resin composition, which is an unstretched film that is not subjected to stretching treatment, can be used as an inexpensive uniaxially molecularly oriented film. - An example of a method for producing an axially oriented film is described in JP-A No. 47-34656. Japanese Patent Publication No. 48-100464. JP 59-127725, JP 59-122726. Special Publication Showa 47-39927. Some of them are disclosed in Japanese Patent Publication No. 53-18072.

The direction of molecular orientation may be horizontal, vertical, or diagonal, and the -axis molecularly oriented thermoplastic resin film is preferably a uniaxially oriented HDPE resin film having a thickness of 10 mm or more.

The two-wheel stretched film may be stretched separately in the vertical direction and in the horizontal direction, or may be stretched in both directions simultaneously.

The two-wheel stretched film used in the present invention has 1
．． This is a film that has been stretched 5 times or more.

Further, the stretched film may be laminated individually as a single layer, or may be laminated as a coextruded layer with the same type of layer or other layers.

The aluminum vacuum-deposited layer preferably has a thickness of 55 to 1,200 mm from the viewpoint of physical strength, light-shielding, antistatic and moisture-proof properties as a laminate, cost, and quality.

In other words, if the thickness is less than 55 mm, it is difficult to reduce the electrification generated on both sides of the vacuum-deposited aluminum layer, and it is difficult to reduce the electrification that occurs on both sides of the vacuum-deposited aluminum layer. It is difficult to ensure the moisture-proofing properties, light blocking properties, gas barrier properties, etc. required for packaging materials for substances.

If the thickness exceeds 1,200 layers, antistatic, moisture-proof, and light-shielding properties can be ensured, but the molecularly oriented thermoplastic resin film deteriorates due to cost and heating during vacuum deposition, causing wrinkles and wrinkles.
There are problems in terms of the appearance of the packaging material that is created due to streaks, a decrease in physical strength, etc.

In particular, a thickness of 80 to 800 thickness is preferred for normal use, and more preferably 100 to 600 thickness.

If necessary, an anchor coat layer may be provided on the molecularly oriented thermoplastic resin film in order to improve the adhesion with the aluminum vacuum-deposited layer. Surface treatments such as irradiation treatment, ozone treatment, chemical treatment, sandblasting treatment, and flame treatment may be performed.

The thermoplastic resin foam sheet, the light-shielding polyolefin resin film, and the aluminum vacuum-deposited molecularly oriented thermoplastic resin film are laminated with or without an adhesive layer.

Lamination of these films can be carried out, for example, by a thermal adhesion method (hot plate adhesion method, flame treatment adhesion method, hot air heat adhesion method).

Impulse adhesive method, ultrasonic adhesive method), adhesive method (wet lamination method, dry lamination method).

hot melt lamination method, extrusion lamination method, coextrusion extrusion lamination method),
etc. are used.

Typical adhesives include various polyethylene resins,
Polyolefin thermoplastic resin hot melt adhesives such as polypropylene resin and polybutene resin, ethylene-propylene copolymer resin, L-LDPE resin, ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer resin, etc. Examples include thermoplastic resin hot-melt adhesives such as olefin copolymer resins, ethylene-acrylic acid copolymer resins, and ionomer resins, and geothermally meltable rubber-based adhesives thereof. Further, as a solution adhesive, there is an adhesive for wet lamination, which is an emulsion or latex adhesive.

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

Typical examples of latex adhesives include natural rubber, styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), and chloroprene rubber (C
There are rubber latexes such as R).

Furthermore, examples of adhesives for dry lamination include polyurethane adhesives. In addition, known adhesives such as hot-melt adhesives, pressure-sensitive adhesives, heat-sensitive adhesives, etc. blended with paraffin wax, microcrystalline wax, ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer resin, etc. are used. You can also do that.

More specifically, preferred representative examples of polyolefin resin adhesives for extrusion lamination include:
Polyolefin resins such as various polyethylene resins, polypropylene resins, polybutylene resins, and ethylene copolymers (EVA, EEA, etc.).

In addition to ethylene, some other monomers (α-olefin) such as L-LDPE resin (EMA, EAA, etc.)
ionomer resins (ionic copolymer resins) such as DuPont's Surlyn and Mitsui Polychemical's Himilan, and various ethylene-modified resins with improved adhesion, such as Mitsui Petrochemical's adhesive polyolefins. Also included are resins such as ADMER.

The packaging material of the present invention can be used for packaging various products, and is particularly suitable for packaging photosensitive materials such as photographic materials, foodstuffs, pharmaceuticals, and chemical substances.

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

When the packaging material of the present invention is applied to, for example, the above-mentioned photographic materials, - Vertical flat bags, double flat bags, self-standing bags, - heavy gusset bags, double gusset bags, laminated films, inner lining of moisture-proof boxes, bright room loading. It can be used for all known forms such as inner lining of light-shielding magazines and leader paper.

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

[Effect]

The present invention has a laminated structure in which a thermoplastic resin foam sheet is placed inside, and light-shielding polyolefin resin films containing an aluminum vacuum-deposited molecularly oriented thermoplastic resin film and an L-LDPE resin, which have different properties, are arranged on both sides.
It is a laminated film with excellent heat retention and appearance, and almost no curling, and has great durability as a packaging material against impact from inside and outside.

〔Example〕

Examples of the packaging material for photosensitive materials of the present invention are shown in Figures 1 to 7.
This will be explained based on the diagram.

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

The packaging material for photosensitive materials shown in Fig. 1 consists of an aluminum vacuum-deposited layer 2 of an aluminum vacuum-deposited multiaxial molecularly oriented thermoplastic resin film (2), which is made by vacuum-depositing an aluminum vacuum-deposited layer 2 on a molecularly-oriented thermoplastic resin film 1, and a light-shielding aluminum vacuum-deposited layer 2. It is composed of six layers in which a thermoplastic resin foam sheet 5 is laminated with a polyolefin resin film 3a via an adhesive layer 4.4.

The packaging material for photosensitive materials shown in FIG.
- A light-shielding multilayer coextruded film Ila consisting of a light-shielding polyolefin resin film 6a that does not contain LDPE resin.
It is composed of seven layers in which a thermoplastic resin foam sheet 5 is laminated between a light-shielding polyolefin resin film 6a and an adhesive layer 4.4.

The packaging material for photosensitive materials shown in Fig. 3 is a thermoplastic material in which an aluminum vacuum-deposited layer 2 of an aluminum vacuum-deposited molecularly oriented thermoplastic resin film 2 and a light-shielding polyolefin resin film 3a are bonded together with a melted thermoplastic resin foam sheet adhesive layer 7. It is composed of six layers of resin foam sheets 5 laminated with adhesive layers 4 interposed therebetween.

The packaging material for photosensitive materials shown in FIG.
The surface of the thermoplastic resin foam sheet 5 is bonded with a molten adhesive layer 7, and the thermoplastic resin foam sheet 5 is bonded with a light-shielding multilayer coextruded film Ila.
It is composed of seven layers adhered by an adhesive layer 7 using a light-shielding polyolefin resin film 6a as an adhesive surface.

The packaging material for photosensitive materials shown in FIG. 5 includes an aluminum vacuum-deposited layer 2 of an aluminum vacuum-deposited -axis molecular-oriented thermoplastic resin film 2, which is obtained by vacuum-depositing an aluminum vacuum-deposited layer 2 on a -axis molecular-oriented thermoplastic resin film 8; Light-shielding polyolefin resin film 3a and thermoplastic resin foam sheet 5
It is composed of five layers in which a thermoplastic resin foam sheet 5 of IVa is laminated with an adhesive layer 4 interposed therebetween.

The packaging material for photosensitive materials shown in FIG. 6 is made by laminating an aluminum vacuum-deposited layer 2 of an aluminum vacuum-deposited - axially oriented thermoplastic resin film (2) and a -axially oriented thermoplastic resin film 8 via an adhesive layer 4. Furthermore, a thermoplastic resin foam sheet 5 and a light-shielding polyolefin resin film 3a are sequentially applied to this −-axis molecularly oriented thermoplastic resin film 8 with an adhesive layer 4.4.
It is composed of eight layers laminated with .

The packaging material for photosensitive materials shown in FIG. 7 consists of an aluminum vacuum-deposited layer 2 of an aluminum vacuum-deposited-axis-oriented thermoplastic resin film 2, and a light-shielding polyolefin resin film 3a.
It is composed of six layers in which a thermoplastic resin foam sheet 5 is laminated with an adhesive layer 4.4 in between.

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

The packaging material for photosensitive materials with comparative holes shown in FIG. It is composed of 5 layers laminated at 6 parts.

The packaging material for photosensitive materials with the comparative hole shown in FIG. 9 is made of four layers, in which an aluminum vacuum-deposited molecularly oriented thermoplastic resin film (■) and a light-shielding polyolefin resin film 3a are laminated with 20 aluminum vacuum-deposited layers via adhesive Ji4. It is configured.

The packaging material for photosensitive materials with the comparison holes shown in Figure 1O is a 3N film in which an aluminum vacuum-deposited molecularly oriented thermoplastic resin film ■ and a light-shielding polyolefin resin film 3a are directly laminated using an extrusion lamination method with aluminum vacuum-deposited N2 on the inside. It consists of

The packaging material for photosensitive materials with comparative holes shown in FIG. 11 includes an aluminum vacuum-deposited thermoplastic resin film (including stretching) and a light-shielding polyolefin resin film 3a.
It is composed of four layers laminated at the aluminum vacuum-deposited layer 2 with an adhesive layer 4 in between.

FIG. 12 is a partial sectional view showing the layer structure of a conventional packaging material for photosensitive materials. It is composed of five layers in which uniaxially oriented thermoplastic resin films 8a, 8a containing a light-shielding substance are laminated on both sides of a thermoplastic resin foam sheet 5 via an adhesive layer 4.4 so that the molecular orientation axes intersect. There is.

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

Invention product I The layer structure of the product 1 of the present invention corresponds to the layer structure shown in FIG.

A biaxially oriented polyester resin film with a thickness of 12 mm was used as the molecularly oriented thermoplastic resin film 1, and the aluminum vacuum deposited layer 2 was made to have a thickness of 400 mm.

The thermoplastic resin foam sheet 3 has a thickness of 0.5 mm+,
A crosslinked LDPE resin foam sheet with a foaming ratio of 30 times was used.

As the light-shielding polyolefin resin film 6a that does not contain L-LDPE resin, 3% by weight of furnace carbon black and HDPE resin (Hyzex 3300F, M
I 0.9 g/10 min, density 0.954 g/ail, made by Mitsui Oil ■) 97 weight 1%, thickness 40-light shielding H
A DPE resin film was used.

As the light-shielding polyolefin resin film 3a, LDP
E resin 5% by weight, furnace carbon black 3% by weight
, ethylene-4 methylpentene-1 copolymer resin (Urtzex 202OL, Melt Index (hereinafter referred to as M
(Displayed as I) 2.1g/10min, density 0.920g/c
An L-LDPE resin film having a thickness of 40 m and consisting of 92% (manufactured by Mitsui Petrochemical Co., Ltd.) and 1% by weight was used.

As adhesive N4, an LDPE resin extrusion laminate adhesive layer with a thickness of 154 mm was used.

Comparison product I The layer structure of comparative product (2) corresponds to the layer structure shown in FIG.

The molecularly oriented thermoplastic resin film 1, the aluminum vacuum-deposited layer 2, the light-shielding polyolefin resin film 5a not containing L-LDPE resin, the light-shielding polyolefin resin film 3a, and the adhesive layer 4 are the same as those of the product (2) of the present invention.

Comparison product ■ The layer structure of comparative product (3) corresponds to the layer structure in FIG. 1O.

The molecularly oriented thermoplastic resin film 1 and the aluminum vacuum-deposited layer 2 are the same as the product I of the present invention.

The light-shielding polyolefin resin film 3a is made of carbon black 3% by weight, ethylene-4 methylpentene-1 copolymer resin (Urtzex 2080C, M17g/10
A light-shielding L-LDPE resin extrusion laminate film with a thickness of 80 mm and having a density of 97% by weight and a density of 0.920 g/c4 Mitsui Oil Co., Ltd. was used.

Conventional product I The layer structure of the conventional product (2) corresponds to the layer structure shown in FIG.

The thermoplastic resin foam sheet 3 is the same as the product I of the present invention except that the thickness is 1-. Light-shielding property - Carbon black 4 with a thickness of 35n is used as the axial molecularly oriented thermoplastic resin film 8a.
．． Contains 5% by weight. Light-shielding oblique uniaxial molecular orientation HDPE
A resin film was used. Adhesive layer 4 is LDP with a thickness of 15-
E resin extrusion laminate adhesive layer was used.

The experimental results are shown in Table 1.

The evaluation is based on the following.

◎...Excellent ○...Excellent...Possible (within practical limits) Mu...Problems (improvement required) ×...Not practical ××...Not a problem* A circular test sample with a diameter of 10 cm was prepared from the laminated film to be tested, and after being left under a 1 kg load plate for 24 hours in an atmosphere with a temperature of 20°C and a humidity of 65% RH, it was placed under the above conditions. Evaluate the curling state after each circular test sample is left on a flat plate for 24 hours without any load. *B Bag-making suitability Strength, appearance, and pinholes of the sealed part when making sealed bags by heat sealing prevention, front/back discrimination, antistatic property,
Comprehensive evaluation of glabella peeling strength, etc. *C Peeling voltage test An endless belt with a width of 35 am and a length of 135°■ is made from the film to be tested, and this belt is charged using a charging device manufactured by Shinra Kagaku ■! The value measured with a voltmeter of the peeling voltage when the SUS roller (stainless steel) weighs 500 g and the SUS roller is fed at a speed of 12 m/min.

*D Heat Resistance After being left under sunlight (80,000 lux) for 3 hours, the rise in surface temperature of the packaging material is measured using a thermistor, and at the same time judged by the touch of the hand.

*E Heat seal suitability Hot tack property, contaminant sealing property, heat seal strength,
Judging from total heat-sealing suitability such as heat-sealing strength retention over time and allowable heat-sealing temperature *F heat retention The inside of the bag after making a sealed bag from each packaging material and leaving it under sunlight (80,000 lux) for 3 hours. The temperature rise was measured using a thermistor, and those with a low temperature rise were marked as ◎ and 0.

〔Effect of the invention〕

Since the present invention is configured as described above, it has less curling, high physical strength, suitability for bag making, antistatic property, heat retention,
A packaging material for photosensitive materials with excellent heat-sealability can be provided at low cost.

[Brief explanation of the drawing]

1 to 7 are partial cross-sectional views showing the layer structure of an example of the packaging material for photosensitive materials of the present invention. 8 to 11 are partial cross-sectional views showing the layer structure of a comparative photosensitive substance packaging material. FIG. 12 is a partial sectional view showing the layer structure of a conventional packaging material for photosensitive materials. 1.1a...Molecularly oriented thermoplastic resin film 2...
Aluminum vacuum deposited layer 3a...light-shielding polyolefin resin film 4.4a
...Adhesive layer 5.5a...Thermoplastic resin foam sheet 6.6a...
L-LDPE resin-free polyolefin resin film 8.8a... - Axial molecular orientation thermoplastic resin film I, I
a... Aluminum vacuum evaporated molecularly oriented thermoplastic resin film ■, Ila... Multilayer coextruded film ■, ma...
Aluminum vacuum vapor deposition - axial molecular orientation thermoplastic resin film ■, IVa...Multilayer coextruded thermoplastic resin foam sheet a...Patent applicant indicating that it contains a light-shielding substance
Fuji Photo Film Co., Ltd. Agent Patent Attorney Japan-China Politics Phonetic Name Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12

Claims (1)

[Claims] A thermoplastic resin foam sheet, a light-shielding polyolefin resin film containing a linear low-density polyethylene resin and a light-shielding substance laminated on one side of the thermoplastic resin foam sheet, and the other side of the thermoplastic resin foam sheet. A photosensitive material comprising an aluminum vacuum-deposited molecularly oriented thermoplastic resin film laminated on a surface thereof, and the aluminum vacuum-deposited layer of the aluminum vacuum-deposited molecularly oriented thermoplastic resin film is located on the thermoplastic resin foam sheet side. Packaging materials for substances