JPH08253270A - Package for multicolor thermosensitive recording material and manufacture thereof - Google Patents

Abstract

PURPOSE: To obtain a package which is excellent in light shielding, cushioning ability and damp-proofness and prevents a colored layer of a multicolor thermosensitive recording material from altering for a long time by forming a bag comprising a laminated structure including an uppermost layer of biaxially drawn polymer or the like, an intermediate layer of a metallic layer and an innermost layer having heat- sealability. CONSTITUTION: A sheet material 12 for constituting layers of a damp-proof bag 12 comprises a laminated structure including an uppermost layer 11 of biaxially drawn polymer or the like, an intermediate layer 12 of a metallic layer and an innermost layer 13 with heat-sealability improved and a frictional coefficient with a received thermosensitive recording material set 7 reduced. Thus a dampproof bag which is excellent in light shielding, cushioning ability and dampproofness and can prevent a colored layer of the multicolor thermosensitive recording material from altering for a long time can be obtained. In addition, an equilibrium moisture content in a space for receiving the multicolor thermosensitive recording material can be maintained for a long time, and an initial state given to the material can be properly maintained for a long time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package used for packaging a multicolor thermosensitive recording material and a method for producing the package.

[0002]

2. Description of the Related Art Thermal recording has a number of advantages such as a simple and highly reliable recording device and maintenance-free operation. The applicant has developed a multicolor thermal recording material capable of recording a full-color image.

A multicolor heat-sensitive recording material which enables full-color image recording is formed on a support by forming a color-forming layer and a color-forming layer on the support in order to prevent the color-forming layer from being colored by frictional heat due to scratching or rubbing. A protective layer for covering is formed.

The color-developing layer on the support has a three-layer structure in which a yellow color-developing layer, a magenta color-developing layer and a cyan color-developing layer are laminated in this order from the side closer to the surface. In addition, each of these color-developing layers causes a predetermined color to develop by a reaction between a color-developing agent and a color-developing agent. A diazonium chloride compound (diazo) is used as the color-developing agent, and the diazo is contained in microcapsules. Dispersed in layers. At the time of image recording, when heat of a predetermined temperature specific to each layer is applied, the molecular chain of the microcapsule expands, and the diazo inside reacts with the developer outside the capsule to develop color, and then each layer. The light having a wavelength peculiar to the is applied to decompose the unnecessary diazo to fix the image recording. Each color can be developed with, for example, 128 gradations, and by superimposing the colors in each color-developing layer, high-quality full-color image recording approaching that of a silver salt photographic system is realized.

By the way, when packaging the thermal recording material, it is necessary to consider that the internal thermal recording material does not react due to the influence of the external environment such as the penetration of external light. Therefore, various contrivances have been made on the material and packaging form of the packaging material, the environment maintenance in the packaging processing process, and the like.

[0006]

The multicolor heat-sensitive recording material for full-color image recording, which is the object of the present invention, is different from the conventional heat-sensitive recording method in the color forming process. The number has increased remarkably, and higher quality control and packaging technology than before are required. For example, since the intended color is produced by superimposing the colors in the respective color-developing layers, even if a part of the color-developing layers is slightly altered due to the influence of external light or the influence of external pressure, the color-developing performance may be significantly reduced.

Further, since the image recording is carried out by a general user, there are cases where the storage condition is not always good. In such a case, the flatness of each sheet of the heat-sensitive recording material is shipped. It is necessary to keep the state almost the same as the time.
In order to maintain the initial state properly until recording an image (or opening the package), it is necessary to strictly control the temperature and humidity of the environment when the package is sealed and the humidity inside the package. In particular, regarding the curl of the heat-sensitive recording material, the environment such as humidity appears remarkably, and it is a problem to strictly control such environment.

Therefore, an object of the present invention is to solve the above problems, and it is excellent in light-shielding property, buffering property, and moisture-proof property, and can prevent deterioration of the color forming layer of a multicolor heat-sensitive recording material for a longer period of time. A multi-color heat-sensitive recording material package and a multi-color heat-sensitive recording material package capable of keeping the environment of the accommodation space of the multi-color heat-sensitive recording material constant for a long time and appropriately maintaining the initial state of the multi-color heat-sensitive recording material for a long time. It is to provide a manufacturing method.

[0009]

The above object of the present invention is a package for containing a multicolor thermosensitive recording material and keeping it in a hermetically sealed state, wherein the package has at least an uppermost layer made of a biaxially oriented polymer or the like. It is achieved by having a bag shape having a laminated structure including an intermediate layer made of a metal layer and an innermost layer having heat sealability.

Further, the above object of the present invention is a method for producing a package for containing a multicolor thermosensitive recording material and keeping it in a hermetically sealed state, wherein the equilibrium water content of the atmosphere in the package is at least 20-.
It is achieved by adjusting at the time of sealing to be in the range of 55%.

[0011]

According to the above-mentioned structure of the present invention, the package has a laminated structure including an uppermost layer made of a biaxially stretched polymer or the like, an intermediate layer made of a metal layer, and an innermost layer having heat sealability. The upper layer secures physical strength, the intermediate layer secures light-shielding and moisture-proof properties, and the innermost layer secures heat sealability.By limiting the purpose of use for each layer, the optimum material that matches the purpose of use of each layer It becomes easier to select various properties, and as a result, it is possible to easily and highly satisfy the required performances, and it is excellent in light-shielding property, buffering property and moisture-proof property, and alteration of the coloring layer of the multicolor thermosensitive recording material. It is possible to obtain a package that can prevent the above-mentioned problem for a longer period of time.

In addition, in the packaging form in which the multicolor heat-sensitive recording material is sealed by the above-mentioned package, since it has excellent moisture resistance, the equilibrium water content in the accommodation space of the multicolor heat-sensitive recording material is prolonged. If the equilibrium moisture content of the atmosphere inside the moisture-proof bag after heat-sealing is adjusted to be in the range of at least 20 to 55%, it is possible to maintain a multi-color The initial state of the thermosensitive recording material can be properly maintained for a long period of time. The equilibrium water content is preferably 25 to 50%.
The range is particularly preferable, and the range of 30 to 45% is particularly preferable.

[0013]

1 to 8 show an embodiment of the present invention, and FIGS. 1 and 2 are perspective views showing a packaging form of a multicolor heat-sensitive recording material for full-color image recording at the time of shipment. 3 and 4 are perspective views showing a manufacturing mode of the package according to the present invention, and FIG.
Is a cross-sectional view showing the structure of a layered sheet material of a bag of a package,
FIG. 6 is a perspective view of a heat sealer, and FIG. 7 is a perspective view of a package in which a multicolor thermosensitive recording material is sealed.

As shown in FIG. 3, the multicolor heat-sensitive recording material 4 for full-color image recording is in the form of a cut sheet, and an appropriate number of sheets (for example, 20 to 50 sheets) are superposed on each other, and the uppermost multicolor heat-sensitive recording material 4 is formed. The heat-sensitive layer 5 of the recording material 4 is overlaid with a protective sheet 6 to form a heat-sensitive recording material set 7, which is then placed in the moisture-proof bag 1.

The protective sheet 6 indicates that when the multicolor heat-sensitive recording material is set in an image recording device (not shown), the last one sheet is used up. In the moisture-proof bag 1 for zero detection. Can be put in.

In the case of this embodiment, the moisture-proof bag 1 has two
3 sheets of the sheet material 2 by stacking the sheet material 2
The edge portions 2a, 2b, 2c on one side are heat-sealed to form a bag shape having an opening 9 on one end side. As shown in FIG. 4, the moisture-proof bag 1 is dimensioned to be long so that a considerable margin X remains on the opening 9 side with respect to the heat-sensitive recording material set 7 contained therein.

As shown in FIG. 5, the sheet material 2 constituting the moisture-proof bag 1 has at least an uppermost layer 11 made of a biaxially oriented polymer, an intermediate layer 12 made of a metal layer,
The innermost layer 13 realizes the improvement of the heat-sealing property and the reduction of the friction coefficient between the heat-sensitive recording material set 7 and the heat-sensitive recording material set 7 contained therein. In the case of this embodiment, the uppermost layer 11 constituting the sheet material 2 has a thickness of 12
A biaxially stretched polyester resin film having a thickness of 9 μm is used, an aluminum foil having a thickness of 9 μm is used as the intermediate layer 12, and a carbon black having a thickness of 60 μm is used as the innermost layer 13.
Adhesive layer 1 with each layer using a black polyethylene layer containing 1% by weight
4 is used, and the total thickness of the sheet material 2 is about 96 μm.

As the uppermost layer 11 constituting the sheet material 2, there are various papers, various plastic films, various nonwoven fabrics, and flexible sheets such as cellophane. As the flexible sheet, various plastic films and cellophane are preferable.

Among the plastic films, the biaxially stretched thermoplastic resin film is particularly preferable. The biaxially stretched thermoplastic resin film is formed by a known biaxial stretching method such as simultaneous biaxial stretching or sequential biaxial stretching, in the vertical direction (MD direction).
And a film stretched in the horizontal direction (CD direction) by 1.5 to 20 times, preferably 3 to 15 times. The thermoplastic resin used for this film includes polyester resin, polyamide (nylon) resin, polyethylene resin,
Polystyrene resin, polypropylene resin, polyolefin copolymer resin, polyvinyl chloride resin, polyvinylidene chloride resin, ethylene vinyl alcohol copolymer resin, vinylon resin, etc. and copolymer resins of these resins and other resins (binary resin Not only polymer resins but also ternary or higher copolymer resins (copolymers may be random copolymers or block copolymers), mixed resins of the above resins and other resins, etc. is there.

The polyester resin may be a resin synthesized from dimethyl terephthalate and ethylene glycol, dimethyl terephthalate and 1,4-cyclohexanedimethanol, dimethyl terephthalate and dimethyl isophthalate. Polyamide resin, nylon 6,
Examples include nylon 66, nylon 12, nylon 11, nylon 6-66 copolymer resin, and the like. Then, these resins are biaxially stretched by a T die film molding machine or an inflation film molding machine to form a film.

The thickness of the biaxially stretched thermoplastic resin film is preferably 5 to 70 μm, particularly preferably 7 to 50 μm, and more preferably 10 to 35 μm in order to make the packaging material thin, reduce the cost and secure the physical strength. Most preferred. If the thickness is less than 5 μm, wrinkles and cuts are likely to occur in the laminating step, and if it exceeds 70 μm, the rigidity is too high and the bag-making property, the gelbotest strength and the handleability are deteriorated, and it is expensive.
In addition, in order to prevent light, prevent glare of the metal layer, and improve lubricity, a semi-transparent, white, yellow, or silver appearance should be obtained by selecting various resins and adding additives selected from various additives. Is preferred. Semi-transparent in the present invention means ASTM
The haze measured by D 1003 is 25% to 98%, preferably 40 to 90%. Further, the biaxially stretched thermoplastic resin film may be a single layer or a multilayer coextruded film having two or more layers. It is preferable that the difference in elongation at break between the vertical and horizontal directions is within 2 times, and preferably within 1.5 times in order to facilitate hand tearing without any difference between the vertical and horizontal directions.

As the cellophane, a commercially available one such as ordinary cellophane defined in JIS Z 1521 or a moisture-proof cellophane coated with vinyl chloride-vinyl acetate copolymer resin or vinylidene chloride resin on the surface of ordinary cellophane is used. be able to.

The metal layer as the intermediate layer 12 is a metal foil such as an aluminum foil, an iron foil, a tin foil, a lead foil, an electrolytic iron foil, a stainless steel foil and a copper foil, and the thickness thereof is preferably 5 to 50 μm, particularly preferably. Is 6 to 30 μm, most preferably 7 to 20 μm
m. Particularly, an aluminum foil having a thickness of 6 to 15 μm is preferable because it is inexpensive and does not adversely affect the photographic light-sensitive material. Further, the metal foil may be a metal thin film processed into a flexible sheet or the like. For this metal thin film,
For example, there is an aluminum vapor deposition film.

The aluminum vapor-deposited film preferably has a thickness of 55 to 1200 Å from the viewpoints of physical strength, light-shielding property, antistatic property, moisture-proof property, gas barrier property and the like as a laminate, cost and quality. That is, if the thickness is less than 55Å, the moisture resistance and the gas barrier property are insufficient, and the electrification generated in the layers on both sides of the aluminum vapor deposition film cannot be reduced. If the thickness exceeds 1200 Å, antistatic property, gas barrier property, moisture proof property and light shielding property can be secured, but cost, deterioration of flexible sheet due to heating by vacuum deposition method and deterioration of physical strength of finished laminated film, etc. There is a problem with. In particular, the thickness of 30 to 800 Å is preferable, and 100 to 600 Å is more preferable for the use of ordinary packaging materials for photographic light-sensitive materials.

To process the aluminum vapor deposition film, a vacuum vapor deposition method, a sputtering method, an ion plating method,
The electron beam evaporation method or the like is used. The aluminum vapor deposition film may be processed not only on one side of the flexible sheet but also on both sides. It is preferable to apply an anchor coating agent on the surface of the flexible sheet or to perform a physical or chemical surface activation treatment such as corona discharge treatment, because the adhesion strength of the aluminum vapor deposition film can be increased.

The aluminum vapor deposition film may be provided with a protective layer for preventing scratches and peeling. As the protective layer, butyral resin, acrylic resin, cellulose resin such as acetate fiber, urethane resin, epoxy resin,
Polyester resin, ionomer resin, ethylene-acrylic acid ester copolymer resin, various polyethylene resins,
Appropriate resins such as polypropylene resin can be used. Also,
Wax, gelatin, polyvinyl alcohol, etc. can also be used. The protective layer is preferably formed to have an extremely thin thickness, and even when it is formed by the extrusion laminating method, the removal of static electricity becomes insufficient unless the thickness is 50 μm or less. When a dry film thickness of 5 μm or less is formed by a known solution coating method, spray coating method, or the like, the aluminum vapor deposition film can be protected and the effect of removing static electricity is large.

A physical surface treatment or AC for improving the adhesion strength between the aluminum vapor deposition film and the flexible sheet.
Specific examples of the agent treatment are shown below. Representative examples of physical surface treatment are shown below. Flame treatment: High running cost and risk of fire. Plasma treatment: Argon gas is converted into plasma to treat the surface. The physical strength is several times that of corona discharge treatment, but the equipment cost is also several tens of times that of corona discharge treatment equipment. Corona discharge treatment: The substrate that can be treated is paper, various polymer films, sheets, aluminum foil, aluminum vacuum deposition film and the like. It is the most widely used, inexpensive and highly effective process. Sandblast treatment: Roughening the surface by blowing silica stone etc. at high pressure. Chemical treatment: Surface treatment with dichromic acid solution, etc. Ozone treatment: Surface treatment is performed in a box filled with ozone. Preheat treatment: A flexible sheet such as film or paper is heat-treated with a heater drum or hot air. In addition, there are ultraviolet irradiation treatment, high frequency heat treatment, electric induction heat treatment, microwave treatment and the like.

AC agent treatment is an AC agent (Anch) which is a general term for adhesion promoters or crosslinking agents used in the laminating industry.
or Coating Agent) is applied. This AC agent is different from a mere adhesive, and is also called a Primer or an Adhesive Promoter, etc., in the sense of chemically adhering, in distinction from an adhesive. Representative examples of AC agents are shown below.

(1) Organic Titanate (Titanium-Based) AC Agent Tetra-propyl-titanate or Tetra-iso-butyl-titan
ate as a main component and Tetra-stearyl as a hydrolysis regulator
-Use by adding titanate. (2) a relatively high polymerization degree polyethylene imine (imine) AC agent polyethyleneimine (-CH ₂ -CH ₂ -NH-n) is used. It is particularly preferable because it is easy to manage and has a long pot life (shelf life). (3) Isocyanate-based AC agent There are one that uses a polymer having an isocyanate group alone (one-pack type) and one that uses it in combination with a polyester having an OH group (two-pack type). A chemical reaction occurs and the adhesive effect appears. The disadvantage is that it has a short pot life and is expensive. (4) Polyester-based and urethane-based AC agents A saturated polyester resin and a urethane resin are used by dissolving them in a solvent such as ethyl acetate and toluene. (5) Polyolefin-based AC agent (6) Polybutadiene-based AC agent

The AC agent layer is preferably formed to have an extremely thin thickness. As a coating method of the AC agent, a gravure roll coating method, a kiss roll coating method, a drop coating method, a bar coating method, a reverse roll coating method, a direct roll coating method, an air knife coating method, or the like is used. Two or more of the physical surface treatments may be used in combination, or the physical surface treatment and the AC agent treatment may be combined.

The innermost layer 13 is preferably a polyolefin resin film containing 50% by weight or more of a heat-sealing polyolefin resin. Examples of the polyolefin resin include homopolyethylene resins of various densities, various ethylene copolymer resins, various polypropylene resins, and polyolefin resin elastomers. 10 from the viewpoint of ensuring heat seal suitability, heat seal strength over time, physical strength, etc.
A polyolefin resin film containing 10% by weight or more of an ethylene copolymer resin by weight% or more is preferable.

Typical examples of the ethylene copolymer resin are shown below. (1) ethylene-resin vinyl copolymer resin (2) ethylene-propylene copolymer resin (3) ethylene-1-butene copolymer resin (4) ethylene-butadiene copolymer resin (5) ethylene-vinyl chloride Copolymer resin (6) Ethylene-methyl methacrylate copolymer resin (7) Ethylene-methyl acrylate copolymer resin (8) Ethylene-ethyl acrylate copolymer resin (hereinafter referred to as EEA resin) (9) Ethylene-acrylonitrile copolymer resin (10) Ethylene-acrylic acid copolymer resin (11) Ionomer resin (resin obtained by crosslinking a copolymer of ethylene and unsaturated acid with a metal such as zinc) (12) Ethylene-α Olefin copolymer resin (L-LD
PE resin) (13) Ethylene-propylene-butene-1 terpolymer resin

Among the ethylene copolymer resins, the L-LDPE resin and the EEA resin are preferable because they have good film moldability and heat seal suitability, and have high bag breaking strength, impact punching strength and tear strength. L-LDPE (Liner Low De
nsity Polystylene) resin is called the third polyethylene resin, and it is a low cost, high strength resin that meets the demands of the times of energy saving and resource saving, which has the advantages of both middle and low density polyethylene resins. This resin is a copolymer obtained by copolymerizing ethylene with an α-olefin having 3 to 13 carbon atoms, preferably 4 to 10 carbon atoms by a low pressure method or a high pressure improvement method, and has a structure having a linear straight chain and short branching. It is a polyolefin copolymer resin. Butene-1 and octene- are preferable α-olefins in terms of physical strength and cost.
1, hexene-1,4-methylpentene-1, heptene-1 and the like are used. The density is generally considered to be low to medium density polyethylene resin, but 0.87-
Many are in the range of 0.95 g / cm ² . Most melt indexes are within the range of 0.1 to 50 g / 10 minutes.

As the polymerization process of the L-LDPE resin, there are a gas phase method using a medium / low pressure apparatus, a liquid phase method and an ionic polymerization method using a high pressure improving apparatus. These L-LDPE
Among the resins, particularly preferable from the viewpoints of physical strength, heat seal strength and film formability, the melt index (hereinafter referred to as MI) is 0.8 to 10 g / 10 minutes (JIS K-6760) and the density is 0. 870 to 0.940 g / cm ² (JIS K-6760), and α-olefin obtained by a liquid phase process and a gas phase process having 6 to 8 carbon atoms.

Specific examples of commercially available L-LDPE resins are shown below. Ethylene / Butene-1 Copolymer Resin G Resin and NUC-FLX (UCC Company) Dourex (Dow Chemical Company) Clearer (Dupont Canada Company) Marlex (Phillips Company) Stamirex (DSM Company) Excellen VL (Sumitomo Chemical Co., Ltd.) Neozex (Mitsui Petrochemical) Mitsubishi Polyethylene-LL (Mitsubishi Petrochemical) Nisseki Linilex (Nippon Petrochemical) NCU Polyethylene-LL (Nippon Unicar) Idemitsu Polyethylene L (Idemitsu Petrochemical) Ethylene / Hexene-1 Copolymer Resin TUFLIN ( UCC) TUFTHENE (Nippon Unicar) Ethylene / 4-methylpentene-1 copolymer resin Ultzex (Mitsui Petrochemical) Ethylene / octene-1 copolymer resin Stamirex (DSM) Dourex (Dow Chemical Co.) Screamer Du Pon Canada Co., Ltd. MORETEC (Idemitsu Petrochemical)

A particularly preferred representative example is the trade name, in which polyethylene has 6 carbon atoms as an α-olefin side chain.
Of Mitsui Petrochemical Co., Ltd., in which 4-methylpentene-1 was introduced, and MORETEC of Idemitsu Petrochemical Co., Ltd. and DSM, in which octene-1 having 8 carbon atoms was introduced as an α-olefin side chain. There are Stamirex and Dowlex from Dow Chemical Co. (these are L-LDPE resins obtained by the co-liquid phase process of four companies). Preferred typical examples obtained by the low-pressure vapor phase process are trade names, which are TUFLIN and UCC of Nippon Unicar Co., Ltd., in which hexene-1 having 6 carbon atoms is introduced as an α-olefin side chain. TUFTTHENE
Etc.

The recently released density is 0.910 g /
Ultra-low-density linear low-density polyethylene resin of less than m ² , for example, NUC-FLX of UCC and Excellen VL of Sumitomo Chemical Co., Ltd. are also preferable (above, products of both companies are butenes having α-olefin of 4 carbon atoms). -1 is used). The EEA resin is
Union Carbide (USA), Nippon Unicar Co., Ltd., Mitsubishi Petrochemical Co., Ltd.
Sumitomo Chemical Co., Ltd., Mitsui Polychemical Co., Ltd., etc.

Various adhesive layers can be used for adhesively laminating the uppermost layer 11, the intermediate layer 12, and the innermost layer 13.
The adhesive layer is made of various polyethylenes (LDPE, L-LDPE, MDPE, HD) used for an extrusion lamination adhesive layer which is inexpensive and has little adverse effect on the photographic light-sensitive material.
PE) resin, various thermoplastic resins such as polypropylene resins, such as polyolefin-based thermoplastic resins, hot-melt adhesives, ethylene-vinyl acetate copolymer resins, ethylene-acrylic acid copolymer resins, ionomer resins and other thermoplastic resins, hot-melt adhesives, heat There are molten rubber adhesives and the like, solution adhesives include wet laminating adhesives, and emulsion and latex adhesives. Representative examples of emulsion type adhesives are polyvinyl acetate resin, vinyl acetate-ethylene copolymer resin, vinyl acetate and acrylic ester copolymer resin, vinyl acetate and maleic ester copolymer resin, acrylic copolymer. There are emulsions of resins and ethylene-acrylic acid copolymer resins. Typical examples of the latex type adhesive include natural rubber and styrene butadiene rubber (SB
R), acrylotolyl butadiene rubber (NBR), chloroprene rubber (CR) and the like.

Examples of the dry laminating adhesive include isocyanate adhesives and urethane adhesives. Other known adhesives such as paraffin wax, microcrystalline wax, ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer resin blended hot melt laminating adhesive, pressure sensitive adhesive, heat sensitive adhesive, etc. Can be used.

More specifically, the polyolefin adhesive for extrusion is not limited to various polyethylene resins, polypropylene resins, polybutylene resins, ethylene copolymer (SVA, EEA, etc.) resins, and ethylene such as L-LDPE resin. A copolymer of some other monomer (α-olefin), Surlyn from Dupont, ionomer resin (ionic copolymer) such as Hiramin from Mitsui Polychemicals, or ethylene modified resin such as Mitsui Petrochemical ( Ltd. Admer (adhesive polymer). Other UV-curable adhesives have recently begun to be used. Especially L
DPE resin and L-LDPE resin are preferable because they are inexpensive and have excellent laminating suitability. Further, a mixed resin or the like in which two or more kinds of the above-mentioned resins are blended to cover the defects of each resin is particularly preferable.

In addition, in the present invention, an additive can be added to each layer if necessary. Next, representative examples of the additives will be described below, but the present invention is not limited thereto and can be selected from all known ones. (Types of Additives) (Representative Examples) (1) Plasticizer: Phthalate ester, glycol ester, fatty acid ester, phosphate ester, etc. (2) Stabilizer: Lead-based, cadmium-based, zinc-based, alkaline earth metal-based, Organic soot type (3) Antistatic agent: Nonionic surfactant, cationic surfactant (4) Filler: Alumina, kaolin, clay, calcium carbonate, mica, talc, titanium oxide, silica, etc. ( 5) Reinforcing agent: glass roving, metal fiber, glass fiber, glass milled fiber, carbon fiber, etc. (6) Foaming agent: Inorganic foaming agent (ammonia carbonate, sodium bicarbonate), organic foaming agent (nitroso type, azo type), etc. (7) Lubricants: Fatty acid amide lubricants, silicones, etc. (8) Deterioration inhibitors: UV absorbers, antioxidants, metal deactivators, peroxide decomposers, etc. (9) Couplings Agents: Silane-based, titanate-based, chromium-based, aluminum-based, etc. (10) Various thermoplastic resins, rubber, etc. (11) Nucleating agents: Organic nucleating agents (dibenzylidene sorbitol compounds, etc.), inorganic nucleating agents ( (12) Various light-shielding substances: carbon black, metal powder, graphite, titanium oxide, beryllium sulfate, etc.

Among these light-shielding substances, an opaque inorganic compound is preferable, and a light-absorbing carbon black is preferable since it is a substance which is excellent in heat resistance and light resistance and is relatively inactive. Gas black, furnace black, channel black, anthracene black, acetylene black, Ketchenger bon black, thermal black, lamp black, oil smoke, pine smoke, animal black,
There are vegetables such as vegetable black. Furnace carbon black is desirable in the present invention for the purpose of light-shielding property, cost, and improvement of physical properties, and acetylene carbon black and Ketjen carbon black which is a modified by-product carbon black are expensive as the light-shielding substance having an antistatic effect. desirable. 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. In Japanese Patent Publication No. 40-26196, which is a publicly known document, a method of dispersing carbon black in a solution of a polymer dissolved in an organic solvent to prepare a master batch of polymer carbon black is disclosed in Japanese Patent Publication No. 43-10362. A method of dispersing black in polyethylene to form a masterbatch is described.

When used as the packaging material for the photographic light-sensitive material of the present invention, no fog is generated, the increase or decrease in the photosensitivity is small, the light-shielding ability is large, and even when it is added to the L-LDPE resin film, it hardens ( In particular, carbon black has a pH of 6.0 to 9.0, an average particle size of 10 to 120 mμ, a volatile component of 2.0% or less, and an oil absorption because it is difficult for pinholes to occur in a film such as fisheyes and fish eyes. Furnace carbon black in an amount of 50 ml / 100 g or more is preferable because it improves the light-shielding property, the dispersibility and the physical strength.

The addition amount is 0.1 to 20% by weight, preferably 0.5 to 15% by weight, and particularly preferably 1.0 to 10% by weight. These various additives may be added to any of the layers, but it is particularly preferable to add a light-shielding substance to the innermost layer 13. It is preferable to add a lubricant, an antistatic agent, or the like to the innermost layer in order to improve antistatic properties and product insertability.

Moisture-proof bag 1 containing the thermosensitive recording material set 7
As shown in FIG. 6, the opening 9 is heat-sealed in a predetermined heat-sealing processing environment in which the heat sealer 50 is installed. Here, the heat-sealing processing environment is one in which the atmosphere such as temperature and humidity is adjusted to the optimum conditions for storing the multicolor thermosensitive recording material 4, and the temperature is preferably about 23 ° C. Humidity is 35
% ± 5% RH is preferable. During the heat-sealing process, the moisture-proof bag 1 degasses the excess gas remaining in the moisture-proof bag 1 and, if necessary, adds a humidity control agent, and then opens the opening 9 in the slit 52 of the heat sealer 50. It is inserted, sandwiched by the movable heating unit 54, and heat-sealed. In this case, the degassing process for removing the gas remaining in the moisture-proof bag 1 is to remove oxygen in the moisture-proof bag 1 to prevent oxidation of the coloring layer of the multicolor thermosensitive recording material 4 in the moisture-proof bag 1. Is intended. Also,
The humidity control agent maintains the equilibrium water content in the atmosphere inside the moisture-proof bag 1 after the opening 9 is sealed at an optimum value.

In this way, by closing the opening 9 by heat sealing, as shown in FIG. 7, a package 3 in which the heat-sensitive recording material set 7 is sealed in the moisture-proof bag 1 is obtained.
In this embodiment, the equilibrium water content of the atmosphere in the moisture-proof bag 1 after the heat-sealing treatment is adjusted by the maintenance of the heat-sealing treatment environment described above and the humidity control agent enclosed in the moisture-proof bag 1 if necessary. The range is adjusted to at least 20 to 55%, preferably 25 to 50%, and particularly preferably 30 to 45%.

The package 3 thus obtained is
As shown in FIG. 1, the extra length portion X is bent to form an individual packaging box 60.
2, a fixed number of individual packaging boxes 60 are packed in a shipping box 70 made of corrugated cardboard or the like and shipped as shown in FIG.

In the laminated sheet material 2 of the moisture-proof bag 1 of the embodiment described above, the uppermost layer 11 secures the physical strength, the intermediate layer 12 secures the light-shielding property and the moisture-proof property, and the innermost layer 13 has the heat-sealing property. By restricting the purpose of use for each layer, such as securing, it becomes easier to select the optimum material that matches the purpose of use of each layer, and as a result, the required performance is easily and
The packaging body 3 can be filled to a high degree, is excellent in light-shielding property, buffering property, and moisture-proof property, and can prevent deterioration of the color forming layer of the multicolor thermosensitive recording material 4 for a longer period of time.

In the package 3 in which the multicolor thermosensitive recording material 4 is sealed by the moistureproof bag 1, the moisture content of the multicolor thermosensitive recording material 4 in the accommodating space of the multicolor thermosensitive recording material 4 is excellent due to the excellent moistureproofness of the moistureproof bag 1. It can be kept constant for a long period of time, and the equilibrium water content of the atmosphere in the moisture-proof bag 1 after the heat-sealing treatment is at least in the range of 20-55%, preferably 25- If it is adjusted to a range of 50%, particularly preferably 30 to 45%,
The initial state applied to the multicolor heat-sensitive recording material 4, especially the curled state, can be appropriately maintained for a long period of time.

The method of manufacturing the moisture-proof bag 1 is not limited to the method of one embodiment in which two sheet materials 2 are superposed and the three edges are heat-sealed. For example, as shown in FIG. 8, the rolled sheet material 2 is folded in two with the innermost layer side facing inward by the curling roller 31, and the descended sheet materials 2 are conveyed in the conveying direction of the sheet material 2 (see FIG. Then, the moisture-proof bag 1 can be obtained by heat-sealing the two sides 32 and 33 orthogonal to the arrow (a) direction and then cutting. With such a manufacturing method, the number of heat-sealed portions is reduced, so that the productivity can be improved.

Further, the number of laminated sheet materials 2 constituting the moisture-proof bag 1 is not limited to that of the embodiment. Middle layer 12
It is also conceivable to use a plurality of layers to form a laminate structure of four or more layers.

[0052]

According to the package of the present invention, it is possible to obtain a moisture-proof bag which is excellent in light-shielding property, cushioning property and moisture-proof property and which can prevent deterioration of the color forming layer of the multicolor thermosensitive recording material for a longer period of time. become. Further, the equilibrium water content in the accommodation space of the multicolor thermosensitive recording material can be kept constant for a long time, and the initial state given to the multicolor thermosensitive recording material can be properly maintained for a long time. .

[Brief description of drawings]

FIG. 1 is a perspective view showing a packaging form of a multicolor thermal recording material according to an embodiment of the present invention at the time of shipment.

FIG. 2 is a perspective view showing a packaging form of the multicolor thermal recording material according to an embodiment of the present invention at the time of shipment.

FIG. 3 is a perspective view showing a manufacturing mode of a package in one embodiment of the present invention.

FIG. 4 is a perspective view showing a manufacturing form of a package according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a structure of a sheet material that constitutes a moisture-proof bag of a package in one embodiment of the present invention.

FIG. 6 is a perspective view of a heat sealer according to an embodiment of the present invention.

FIG. 7 is a perspective view of a package according to an embodiment of the present invention.

FIG. 8 is an explanatory view of another production example of the moisture-proof bag according to the present invention.

[Explanation of symbols]

 1 moisture-proof bag 2 sheet material 3 package 4 multicolor thermosensitive recording material 5 thermosensitive layer 6 protective sheet 7 thermosensitive recording material set 9 opening 11 uppermost layer 12 intermediate layer 13 innermost layer 14 adhesive layer 50 heat sealer 52 slit 54 heating section 60 individual packaging box 70 transport box 31 roller 32 heat seal part 33 heat seal part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03C 3/00 585 B41M 5/18 D

Claims (2)

[Claims] 1. A package for enclosing a multicolor heat-sensitive recording material in a hermetically sealed state, wherein the package has at least an uppermost layer made of a biaxially stretched polymer, an intermediate layer made of a metal layer, and a heat-sealing property. A package having a bag shape having a laminated structure including the innermost layer. 2. A method of manufacturing a package for enclosing a multicolor thermosensitive recording material in a hermetically sealed state, wherein the equilibrium water content of the atmosphere in the package is at least 20.
A method for producing a package, which is characterized in that the range is adjusted to 55% at the time of sealing.