JPH07119094B2 - Packaging material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a packaging material suitable for packaging a relatively heavy article such as a film roll film for movies among various photographic photosensitive materials, photosensitive materials, electronic parts and the like. It is a thing.

[Conventional technology]

In general, as a packaging material for high-tech products such as photographic photosensitive materials, in addition to completely blocking light, gas barrier properties,
Moisture resistance, physical strength (breaking strength, tear strength, impact drilling strength, gelbotest strength, wear strength, etc.), heat sealability (heat seal strength, cut sealability, hot tack property, foreign matter seal property, etc.), antistatic property It is required to satisfy various characteristics such as smoothness, low dust generation and flatness. It is extremely difficult to combine these properties with a single film material, and conventionally, a packaging material having a plurality of layers has been used.

The present inventor has diligently studied in order to improve a packaging material for a photosensitive material, and has already disclosed a material in which the material strength is improved by combining two layers of uniaxially stretched film (JP-A-57-6754). ing.

Further, in a three-layer laminated film obtained by laminating a uniaxial molecular orientation thermoplastic resin film on both sides of a sheet-shaped foam, the thickness of the sheet-shaped foam is 0.3 to 2.0 mm, and the expansion ratio is 5 to 50 times. And the bilayer uniaxial molecular orientation film is
The molecular orientation axes are intersected at an angle of 30 degrees or more, and the foam is heat-melt-bonded on both sides with or without a heat-melt adhesive layer, and the thickness of the laminated film is 40 of the theoretical sum of each layer. ~ 85
It has already been disclosed a laminated film excellent in impact hole rake strength and gelvotest strength compressed to a thickness of 0.1% (residual thickness ratio) and small curling, which is particularly excellent as a packaging material for heavy objects (JP-A-59-201848). Issue).

[Problems to be Solved by the Invention]

In the packaging material composed of such a plurality of layers, since each film layer is laminated with an adhesive layer or laminated by coextrusion, each layer is completely integrated and adhered to be hard,
The physical strength was low and the curl was large. Also, a step of providing an adhesive layer is required, resulting in process loss,
There was an inherent problem of high process costs.

In addition, it is difficult to distinguish between the front and the back under a safelight, which is a packaging material for photosensitive materials, and not only does the quality of the photosensitive material in the packaging material deteriorate due to the high temperature caused by sunlight, but it also causes melt adhesion under strong sunlight in the summer. There were things.

Further, when a co-extruded T-die film or an inflation film is laminated to form a laminated film having a plurality of constitutions, trimming loss is large and it is uneconomical.

The present invention solves the above problems, is inexpensive and has an excellent appearance,
An object of the present invention is to provide a packaging material having a large physical strength, a small curl, flexibility, good front / back distinction under a safelight, and good temperature rise prevention under sunlight.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention has a light-reflecting flexible sealing layer and a film layer pseudo-adhered by blocking which has been conventionally regarded as a failure without using an adhesive layer. .

That is, the packaging material of the present invention comprises a pseudo-adhesive layer in which two ethylene acrylate resin film layers, which are the inner layers of the multilayer coextrusion film, are mounted by blocking, and a light-reflecting flexible sheet layer. Is configured. Preferably comprising a multilayer coextrusion blocking laminated film layer having a pseudo-adhesive layer in which the inner layers of the light reflecting flexible sheet layer and the multilayer coextruded inflation film are adhered by blocking, the multilayer coextruded inflation film,
50% ethylene acrylate resin with a methyl acrylate and / or ethyl acrylate content of 7% by weight or more
It has an inner ethylene acrylate resin film layer containing 0.01% to 2.00% by weight of an antioxidant and 0.01 to 2.00% by weight of an antioxidant, and an outer thermoplastic resin film layer containing an antiblocking substance.

The light-reflecting flexible sheet layer is, for example, a light-reflecting light-shielding film layer obtained by adding a light-reflecting light-shielding substance to a metal foil layer and / or a metal thin film processed flexible sheet layer and / or a thermoplastic resin. Typical examples of the metal foil layer are aluminum foil, tin foil, iron foil, etc., and typical examples of the metal thin film processed flexible sheet layer are, for example, aluminum vacuum vapor deposition film, aluminum vacuum vapor deposition paper, etc. Thermoplastic resin is
Polyolefin resin, polyester resin, polyamide resin, etc. are used, and among these, polyolefin resin is preferable, especially high density polyethylene (hereinafter referred to as HDPE) resin, polypropylene resin, which has a large moisture resistance.
L-LDPE resins or mixed resins containing these resins are preferable.

As the light-reflective light-shielding substance, metal powder, white or pale yellow pigment, or the like is used. The metal powder is aluminum powder, aluminum paste, tin powder powder, nickel powder, zinc powder, or powder of these metal alloys or metal compounds.

The aluminum paste here means that when an aluminum powder is produced by a known method such as a ball mill method, a stamp mill method or an atomizing method, a higher amount of stearic acid such as mineral spirit or a higher fatty acid such as oleic acid or a higher fatty acid derivative is used. It was made into a paste in the presence. In the light-reflecting light-shielding film layer of the present invention, this aluminum paste and a polyolefin-based thermoplastic resin (various polypropylene resin, various polyethylene resin, EVA resin, E
EA resin, EAA resin, etc.) are heated and kneaded, and low volatile substances (mainly mineral spirits with a strong malodor) are heated and / or removed by a vacuum pump or the like and used as an aluminum paste compound resin or an aluminum paste masterbatch resin.

In particular, it is preferable to use it as an aluminum paste masterbatch resin in order to eliminate adverse effects and odors on the photographic light-sensitive material.

It is particularly preferable to use a higher fatty acid and / or higher fatty acid derivative in an amount of 0.1 to 10 without using a solution such as mineral spirits.
It is a resin in which a thermoplastic resin is kneaded in a required amount with a metal powder in which the periphery of aluminum whose weight ratio is 90% to 99.9% by weight of aluminum powder is completely covered with higher fatty acid and / or higher fatty acid derivative.

In addition to aluminum powder, molten aluminum is powdered by atomizing method, granulating method, rotary disc dropping method, evaporation method, etc., and aluminum foil is crushed by a ball mill method, a stamp mill method or the like into flakes. Including what you did. Since it is unstable in the aluminum powder unit, various known treatments for inactivating the surface of the aluminum powder are performed, for example, surface coating of the aluminum powder with a higher fatty acid or the like.

The addition amount of this metal powder is preferably 0.1 to 20% by weight,
A particularly preferred range is 1 to 6% by weight.

The thickness of the light-reflecting flexible sheet layer is preferably 5 μm or more, and particularly preferably 10 μm or more, from the viewpoint of suitability for lamination.

The multi-layer coextrusion blocking laminated film layer has a pseudo adhesive layer internally pseudo bonded by blocking. This pseudo-adhesive layer is made of an ethylene acrylic acid ester resin film layer, and is not completely fixed integrally like the adhesive layer, but does not cause any problems during lamination or bag making Pseudo-adhesion is applied in a weak and flexible state, improving workability in packaging and physical strength and preventing curling.

This ethylene acrylate resin film layer contains 50 wt% or more of ethylene acrylate resin. Ethylene acrylate resin content is 50% by weight
If it is less than the above range, the flexibility is insufficient, blocking is less likely to occur, the low-temperature heat-sealing property of the pseudo adhesive layer is insufficient, and the physical strength improving effect is small. When a light-shielding substance or the like is included, uniform dispersibility is lacking, and fisheyes and spots often occur.

The ethylene acrylic acid ester resin film layer contains 7 wt% or more of methyl acrylate and / or ethyl acrylate. When the content is less than 7% by weight, blocking is less likely to occur, flexibility is poor, impact drilling strength is small, physical strength improving effect is small, and the effect of the present invention is not exerted.

The ethylene acrylate resin film layer contains 0.01 to 2.00% by weight or more of an antioxidant. If the antioxidant content is less than 0.01% by weight, the antioxidant effect of the resin will be small, and the appearance of the packaging material will be deteriorated due to the increase in the occurrence of spots due to resin burn, and it was also used for packaging photographic light-sensitive materials. In this case, failure such as pressure fog will occur. Also,
If the amount exceeds 2.00% by weight, it not only adversely affects the photographic light-sensitive material that uses the oxidation / reduction effect (for example, deterioration of photographic characteristics such as fog and sensitization / desensitization), but also bleeds out over time to deteriorate the appearance. Let

Representative examples of the antioxidant are shown below, but it goes without saying that the present invention is not limited to these.

Phenolic n-octadecyl-3 (3 ', 5'-di-t-butyl 4'
Hydroxyphenyl) propinate, 2,6 di-t-butyl 4-methylphenol, 2,6 di-t-butyl-p-cresol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4 4,4'-thiobis (3-methyl 6-t-butylphenol, 4,4'-butylidene bis (3-methyl-6-t-butylphenol), stearyl-β (3,5-di-4-butyl 4-hydroxyphenyl) ) Propionate, 1,1,3-tris ((2-methyl-4-hydroxy-5-
t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, octadecyl-3- (3,5-di) -T-butyl-4-hydroxyphenyl) propionate, tetrakis [methylene-3 (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, etc. Sulfur-based dilauryl-3,3'-thio Dipropionate, dimyristyl-3,3′-thiodipropionate, lauryl stearyl thiodipropionate, distearyl-3′-thiodipropionate, ditridecyl-3,3′-thiodipropionate Phosphorus trinonyl Phenyl phosphite, triphenyl phosphite, etc. Especially 2,6-di-t-butyl-p-cresol (BHT) and low volatility high molecular weight phenolic antioxidant ( Product name Irega
Nox 1010, Iriganox 330, Topano ICA, etc.), dilauryl thiodipropionate, distearyl thiodipropionate, dialkyl phosphate and the like, and it is effective to use one or more, particularly two or more thereof in combination.

For pseudo-adhesion of the ethylene acrylic ester type resin ferm layer by blocking, for example, when a multilayer coextrusion inflation film is formed by a multilayer coextrusion inflation method, a new nip roll for take-up or a new nip roll for take-up is newly provided. This is performed by pressing the ethylene acrylic acid ester resin film layer with a pressure roll or the like. Round die method The round die (ring die) used in the multi-layer coextrusion blown film molding machine is roughly classified into three methods: an in-die laminating method, an outside die laminating method, and a laminar flow supply method. It is preferable because the interlayer adhesion is large.

Also, in the case of blown film, there is no ear loss like the conventional laminated film and the laminated film can be manufactured at the same time as the blown film can be formed, so that the film can be effectively used and stable, and wrinkles, melt fracture, etc. hardly occur. Good moldability.

A thermoplastic resin film layer is laminated on the outside of the ethylene acrylic acid ester-based resin film layer, and the thermoplastic resin film layer contains an antiblocking substance. If the antiblocking substance is not contained, the multilayer coextruded film is wound up, and when temporarily stored, the entire roll causes blocking and becomes unusable.

In the present invention, the anti-blocking substance is silica, diatomaceous earth, talc, calcium silicate, aluminum silicate, magnesium silicate, calcium carbonate, higher fatty acid polyvinyl ester, n-octadecyl urea,
Various anti-blocking agents such as dicarboxylic acid ester amides and N, N'-dioleyl oxamide, and various later-described lubricants and light-shielding substances having an anti-blocking effect are included. Particularly, carbon black, fatty acid amide, silica, talc, calcium carbonate, metal powder, and titanium oxide are preferable.

Known films of various polyethylene resins, ethylene copolymer resins, polypropylene resins, polyvinyl chloride resins, polyvinylidene chloride resins, various polyamide resins, polycarbonate resins, various polyester resins, etc. if they contain anti-blocking substances , And films made of these modified resins and mixed resins can be used.

In addition, the thermoplastic resin film layer has a sliding angle of 6 to 30 degrees in order to improve sliding during blown film molding, lamination with other film layers, bag making, product packaging, etc., and to prevent wrinkles. It is preferable that

This slip angle is obtained by cutting out a part of the laminated film to be tested and attaching it to the bottom surface of a metal plate block with a length of 75 ^mm × a width of 35 ^mm and a load of 2000 g, with the laminated film surface of the block on the inclined surface. Then, the inclination angle of this inclined surface is changed and the angle at which the block starts to slide is read.

If the slip angle is less than 6 degrees, slippage occurs during winding of the laminated film, causing winding deviation, which makes practical application difficult.
In addition, stacking packaging materials using the packaging material of the present invention tends to cause load collapse.

Further, if the sliding angle exceeds 30 degrees, not only does the frictional resistance with the guide plate increase during film forming, wrinkles and streaks are generated, but also many troubles are likely to occur in the processing and packaging process for packaging products.

Further, the thermoplastic resin film layer preferably has a softening point (ASTM D 1525) higher than that of the ethylene acrylate resin film layer by 5 ° C. or more in order to produce bag-making suitability and blocking.

A light-shielding substance may be added to the ethylene acrylic acid ester-based resin film layer or the thermoplastic resin film layer in order to secure light-shielding properties.

This light-shielding substance means a substance that can be kneaded or dispersed in each layer and does not transmit visible light, infrared light, ultraviolet light, or 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, inorganic pigments and coloring dyes.

Among these light-shielding substances, from the viewpoints of quality, cost, light-shielding ability, etc., a coloring substance that easily absorbs or reflects light, particularly a carbon black of various pigments, aluminum powder of metal powder, and a lower volatile substance than the aluminum paste are used. Those removed are preferred.

As a method of blending these light-shielding substances into each layer, there are a masterbatch coloring method, a compound coloring method, and the like, which have been often performed conventionally. The light-shielding substances are classified into powder colorants, paste colorants, wet colorants, masterbatches, facial cleansers, colored pellets, etc. depending on the resin used, the machine used, the cost, and the like.

From the viewpoint of ensuring light-shielding properties, improving cost and physical strength, furnace carbon black having an average particle diameter of 200 mμ or less is preferable, and acetylene carbon black and Ketjen are expensive as light-shielding substances having an antistatic effect. Carbon black, graphite and the like are preferable. If necessary, it is also preferable to mix and use two or more kinds of light-shielding substances according to the required characteristics. Even in this case, 0.5g / m ^{2 to} 50g / m of the light-shielding substance with an average particle size of 200mμ or less
It is preferable to include it in ^two laminated films. On the other hand, among these carbon blacks, pH 5-9, average particle size 10-1
20mμ is preferred, especially pH 6-9, average particle size 50
Furnace carbon black of mμ or less is preferable. By using such a large pH and particle size,
Fog is less likely to occur, and sensitivity is less likely to increase or decrease.
It is possible to obtain a packaging material having a large light-shielding ability, few occurrences of pinholes due to carbon black lumps, fish eyes, etc., improved physical strength, and improved heat seal suitability.

Although there are various forms of blending the light-shielding substance in each layer as described above, the masterbatch method is preferable in terms of cost reduction, prevention of contamination of the workplace, and the like.

Further, if similar adhesiveness can be secured, it is preferable to add a lubricant to each layer in order to improve film moldability, lubricity, and processability. Examples of known lubricants include waxes, fatty alcohols, glycerin fatty acid esters, fatty acid amides, silicones, fatty acid esters with lower alcohols, paraffins and α-olefin-maleic acid copolymers.

Typical lubricants and their manufacturer names are listed below,
The present invention is not limited to these.

(1) Silicone-based lubricants; various grades of dimethylpolysiloxane (Shin-Etsu Silicone, Toray Silicone), etc. (2) Oleic amide-based lubricants: Armoslip CP (Lion Akzo), Neutron (Nippon Seika), Neutron E -18 (Nippon Seika), Amide O (Nitto Kagaku),
Alfro-E-10 (Nippon Yushi), Diamond Mid O-200
(Nippon Kasei), Diamid G-200 (Nippon Kasei), etc. (3) Erucamide amide lubricant; Alfuro-P-10 (Nippon Oil & Fats), Neutron (Nippon Seika), etc. (4) Stearamide amide Lubricant; Alfro-S-10
(Nippon Yushi), Neutron 2 (Nippon Seika), Diamid 200 (Nippon Kasei), etc. (5) Bis fatty acid amide lubricant; Bisamide (Nippon Kasei), Diamid 200 bis (Nippon Kasei), Armowax EBS ( (Lion Akzo) etc. (6) Alkylamine lubricants; Electrostripers
There is TS-2 (Kao soap) etc.

When used for packaging photographic light-sensitive materials, the amount of these lubricants that do not adversely affect the photographic light-sensitive material is 0.01 to 1.0% by weight, and they may be used alone or in combination of two kinds. The preferred fatty acid amide lubricant of the present invention has 8 carbon atoms.
-50, particularly preferably 15-35.

The multi-layer coextrusion blown film is an intermediate layer between the ethylene acrylic acid ester resin film layer and the thermoplastic resin film layer as long as it is configured to include at least the above ethylene acrylic acid ester resin film layer and the plastic resin light-shielding film layer. May be laminated.

Then, the inner layers of the multilayer coextrusion blown film are pseudo-adhered to each other by blocking to form a multilayer coextrusion blocking laminated film layer, and the multilayer coextrusion blocking laminated film layer and the light reflection flexible sheet layer are laminated. There is. In order to laminate the multilayer coextrusion blocking laminated film layer and the light-reflecting flexible sheet layer, various known methods may be used, such as thermal bonding method (hot plate bonding method, flame treatment bonding method, impulse bonding method, ultrasonic bonding method). ), Adhesive method (wet laminating method, dry laminating method, hot melt laminating method,
Extrusion lamination method, co-extrusion lamination method), etc. are used.

Typical adhesives include various polyolefin-based thermoplastic resin hot melt adhesives, ethylene-propylene copolymer resins, ethylene-vinyl acetate copolymer resins, ethylene copolymers such as ethylene-ethyl acrylate copolymers. Resin, ethylene-acrylic acid copolymer resin, thermoplastic resin such as ionomer resin, etc. There are heat melting adhesives and other heat melting type rubber adhesives. Emulsion, latex-like adhesive, and representative examples of emulsion-type adhesive include polyvinyl acetate resin, vinyl acetate-ethylene copolymer resin, vinyl acetate resin and acrylic ester copolymer resin, vinyl acetate resin. There are emulsions of maleic acid ester copolymer resin, acrylic acid copolymer resin, ethylene-acrylic acid copolymer resin and the like. Typical examples of latex type adhesives include natural rubber, styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR),
There is rubber latex such as chloroprene rubber (CR).
Also, as adhesives for dry lamination, there are isocyanate adhesives, urethane adhesives, polyester adhesives, and blends of microcrystalline wax, ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer resin, etc. Known adhesives such as hot-melt laminating adhesives, pressure-sensitive adhesives, and heat-sensitive adhesives can also be used. More specifically, polyolefin resin adhesives for extrusion lamination include polyolefin resins such as various polyethylene resins, polypropylene resins, polybutylene resins, ethylene copolymers and ethylene copolymer (EVA, EEA, etc.) resins. , L-LDPE resin, which is obtained by partially copolymerizing ethylene with another monomer (α-olefin), ionomer resin (ion copolymer resin) such as Surlyn of Dupont and Himiran of Mitsui Polychemical. There is Admer (adhesive polymer) of Mitsui Petrochemical Co., Ltd. Other UV curable adhesives have also begun to be used recently.

In particular, LDPE resin and L-LDPE resin are preferable because they are inexpensive and have excellent laminating suitability. Further, a mixed resin in which two or more kinds of the above-mentioned resins are blended to cover the defects of each resin is particularly preferable.

The thickness of the adhesive layer by the extrusion lamination method using a thermoplastic resin is usually 6 μm to 50 μm, preferably 10 μm to 20 μm, but it is based on the cost, the adhesive strength, the laminating speed, the total thickness of the laminate, etc. However, the numerical value is not particularly limited.

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 light-sensitive materials, foods, pharmaceuticals, and 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. It is suitable for the photographic light-sensitive material.

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 any known form such as inside sticking of a light chamber loading light-shielding magazine, a moisture-proof light-shielding bag of a light chamber 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 packaging material of the present invention, the light-reflecting flexible sheet layer improves the printability and the front / back distinction under safelight, and prevents the temperature rise under sunlight, and the multilayer coextrusion blocking laminated film layer has a tear strength. It has improved curl and reduced curl.

〔Example〕

Examples of the packaging material according to the present invention will be described below with reference to FIGS.
It will be described with reference to the drawings.

1 to 7 are partial cross-sectional views showing the layer structure of a typical packaging material of the present invention.

The packaging material shown in FIG. 1 is a light reflecting flexible sheet layer 1
A multi-layer coextrusion blocking laminated film layer 2 laminated with an adhesive layer 3. The multi-layer coextrusion resin light-shielding film layer 2 comprises an inner layer of an ethylene acrylic acid ester resin film layer 4 and an outer layer of a thermoplastic resin. Film layer 5
5, and the ethylene acrylic acid ester-based resin film layer 4 and the thermoplastic resin film layer 5 are a two-layer coextrusion film 6 formed by a round die method two-layer coextrusion inflation film molding machine. And the inner layer of ethylene acrylate resin film layer 4
・ 4 is pseudo glued by blocking.

The packaging material of FIG. 2 is the same as the packaging material of FIG. 1 except that the thermoplastic resin film layer 5a is used as the outer layer having a light shielding property.

The packaging material of FIG. 3 is the same as the packaging material of FIG. 1 except that the thermoplastic resin film layer 5a and the ethylene acrylate resin film layer 4a having a light blocking property are used.

The packaging material of FIG. 4 is the same as the packaging material of FIG. 1 except that the ethylene acrylic ester resin film layer 4a having a light shielding property is used.

The packaging material shown in FIG. 5 is composed of 6 layers of an inner layer of ethylene acrylic acid ester-based resin film layers 4 and 4, an intermediate layer of 7 and an outer layer of thermoplastic resin film layers 5 and 5, and these ethylene acryl The acid ester resin film layer 4, the intermediate layer 7, and the thermoplastic resin film layer 5 are the three-layer coextrusion film 8 formed by the round die method three-layer coextrusion inflation film molding method. The ethylene acrylic ester resin film layers 4 and 4 are pseudo-bonded by blocking.

The packaging material of FIG. 6 is the same as the packaging material of FIG. 5 except that each layer has a light-shielding property except for the adhesive layer 3.

The packaging material of FIG. 7 is an inner layer of ethylene acrylic acid ester resin film layers 4 and 4, intermediate layers 71 and 71, intermediate layers 72a and 72a having a light shielding property, and an outer layer of a thermoplastic resin having a light shielding property. It is composed of resin film layers 5a and 5a, and these ethylene acrylic acid ester-based resin film layers 4 and intermediate layers
71.72a and the thermoplastic resin film layer 5a are formed by the round die method 4
A four-layer coextrusion film 9a formed by a layer coextrusion inflation film molding method. The ethylene acrylic ester resin film layers 4 and 4 are pseudo-bonded by blocking.

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

Invention Product I Invention invention I corresponds to the layer structure of FIG.

One layer of the light-reflecting flexible sheet was an aluminum vacuum vapor-deposited biaxially stretched nylon film in which a 400-Å-thick aluminum vacuum vapor deposition layer was provided on a 15 μm-thick biaxially stretched nylon film. The laminated structure was such that the biaxially stretched nylon film was on the outside and the aluminum vacuum deposition layer was on the inside.

The ethylene acrylic ester resin film layer 4 has a comonomer content of 18% by weight, MI of 6 g / 10 minutes, and density of 0.93 g.
/ 10 cm ³ , 70% by weight of EEA resin with a Vicat softening point of 56 ° C. and an ethylene copolymer resin of ethylene and octene-1 with a density of 0.920 g / cm ³ , MI of 2 g / 10 minutes and a Vicat softening point of 96. ℃
30% by weight of L-LDPE resin, and has a thickness of 25 μm. The thermoplastic resin film layer 5a has a density of 0.954 g
It is a copolymer resin of ethylene and 4-methylpentene-1 with 20% by weight of HDPE resin having a Vicat softening point of 126 ° C./cm ³ , MI of 1.1 g / 10 min. Density 0.920g / cm ³ , MI 2.1g / 10
Min., Vicat softening point 100 ° C L-LDPE resin 76.95% by weight
And 3% by weight of carbon black and 0. oleic acid amide.
It is composed of 05% by weight and has a thickness of 25 μm and a sliding angle of 9 to 30 degrees.

As the adhesive layer 3, an extrusion lamination adhesive layer having a thickness of 15 μm and made of a high pressure branched low density polyethylene (LDPE) resin having an MI of 5.1 g / 10 minutes and a density of 0.919 g / cm ³ was used.

Inventive product II The inventive product II corresponds to the layer structure shown in FIG.

As the light-reflecting flexible sheet layer 1, an aluminum vacuum vapor-deposited biaxially stretched polyester film obtained by forming a 400 μm-thick aluminum vacuum vapor-deposited layer on a 12 μm-thick biaxially stretched polyester film was used. The layer structure was such that the biaxially stretched polyester film was on the outside and the aluminum vacuum deposition layer was on the inside.

The ethylene acrylate resin film layer 4a has a comonomer content of 15% by weight, an MI of 1.5 g / 10 minutes, and a density of 0.9.
30 g / 10 cm ^3, the density Vicat softening point of the ethylene copolymer resin of 61 ° C. of EEA resin 60 wt% of ethylene and butene-1 0.890 g / cm ^3, MI is 1 g / 10 min, Vicat softening point 58 ° C
38% by weight of L-LDPE resin and 2% by weight of carbon black, and has a thickness of 25 μm.

The thermoplastic resin film layer 5a is the same as the product I of the present invention.

The adhesive layer 3 is the same as the product I of the present invention.

Invention product III Invention product III also corresponds to the layer structure of FIG.

The light reflecting flexible sheet layer 1 is the same as the product of the present invention.

The ethylene acrylate resin film layer 4a has a comonomer content of 20% by weight, an MI of 20 g / 10 minutes, and a density of 0.93.
g / cm ³ , 60% by weight of EEA resin with a Vicat softening point of 50 ° C and the density of ethylene and butene-1 which is an ethylene copolymer resin
It is composed of 37% by weight of L-LDPE resin having 0.906 g / cm ³ , MI of 0.8 g / 10 minutes, Vicat softening point of 84 ° C. and 3% by weight of carbon black, and has a thickness of 25 μm.

The thermoplastic resin film layer 5a is the same as the product I of the present invention.

The adhesive layer 3 is the same as the product I of the present invention.

Inventive product IV Inventive product IV also corresponds to the layer structure shown in FIG.

As the light-reflecting flexible sheet layer, an aluminum vacuum vapor-deposited biaxially-stretched polypropylene film was used in which a 400 μm-thick aluminum vacuum vapor-deposited layer was provided on a 20 μm-thick biaxially-stretched polyester film. The biaxially stretched polypropylene film was laminated on the outer side and the aluminum vacuum deposition layer was on the inner side.

The ethylene acrylic acid ester-based resin film layer 4a is made of the same resin composition as the product II of the present invention, and has a thickness of 30 μm.

The thermoplastic resin film layer 5a has a density of 0.923 g / cm ³ and an MI of
2.4g / 10min, 5% by weight of L-LDPE resin with a Vicat softening point of 92 ° C, and 92% by weight of HDPE resin with a density of 0.964g / cm ³ , MI of 0.4g / 10min, Vicat softening point of 128 ° C. And 3% by weight of carbon black, having a thickness of 20 μm and a sliding angle of 9 to 30 degrees.

The adhesive layer 3 is the same as the product I of the present invention.

Inventive product V Inventive product V also corresponds to the layer structure shown in FIG.

The light-reflecting flexible sheet layer 1 has a density of 0.964 g / cm ³ ,
An aluminum vacuum vapor deposition oblique uniaxial molecular orientation HDPE film having a 400 Å thick aluminum vacuum vapor deposition layer was used for a 35 μm thick diagonal uniaxial molecular orientation HDPE film using an HDPE resin having an MI of 0.4 g / 10 min. Diagonal uniaxial molecular orientation HD
The PE film was laminated with the aluminum vacuum deposition layer on the outside and the aluminum vacuum deposition layer on the inside.

The ethylene acrylate resin film layer 4a has a comonomer content of 20% by weight, an MI of 20 g / 10 minutes, and a density of 0.93.
g / cm ³ , the Vicat softening point is 50 wt% EEA resin 60% by weight and the density of ethylene copolymer resin of ethylene and 4-methylpentene-1 is 0.920 g / cm ³ , MI is 2.1 g / 10 minutes, It is composed of 38% by weight of L-LDPE resin having a Vicat softening point of 100 ° C. and 2% by weight of carbon black and has a thickness of 25 μm.

The thermoplastic resin film layer 5a is the same as the product I of the present invention.

The adhesive layer 3 is the same as the product I of the present invention.

Comparative product I A layer formed with the same resin composition as the ethylene acrylic ester resin film layer 4 of the invention product IV to a thickness of 50 μm,
A packaging material for a two-layer coextrusion film comprising a thermoplastic resin film layer of Product IV of the present invention and a layer formed with the same resin composition and having a thickness of 50 μm. The light-reflecting flexible sheet layer 1 and the adhesive layer 3 were the same as those of the product IV of the present invention.

In the above invention products, the measuring method of each property was as follows.

Shown in JIS K7206 = ASTM D1525 Experimental Results Table 1; MI (g / 10 min); JIS K6760 = ASTM D1238 ( 190 ℃) Density ^{(g / cm 3); JIS} K6760 = ASTM D1505 Vicat softening point (℃) .

The evaluation is as follows.

◎… very good ○… excellent ●… possible (within practical limits) ▲… problematic (needs improvement) ×… not practical * A surface smoothness of multi-layer coextrusion inflation film Judgment based on the degree of occurrence of melt fracture (Melt Fracture) when forming a film with the resin prescription layer thickness described using an extrusion blown film molding machine * B Packaging material curling width 80 cm, length 1 m packaging material vertical Judgment based on the curling state that occurs when spilling (judgment based on processing machine suitability) * C Multilayer coextrusion inflation film moldability Simultaneous two-layer coextrusion inflation film molding machine Low current load when forming film with thickness, bubble stability, film wrinkling Judgment based on smallness etc. [Effect of the invention] Since the present invention comprises a light-reflecting flexible sheet layer and a multi-layer coextrusion blocking laminated film layer, physical properties such as tear strength, gelbotest strength, burst strength, impact punching strength, etc. The strength is significantly improved, curling hardly occurs, printability, front / back distinction under safelight and antistatic property are improved, and further temperature rise under sunlight can be prevented.

[Brief description of drawings]

1 to 7 are partial cross-sectional views showing the layer structure of an embodiment of the packaging material according to the present invention. 1 …… Light-reflecting flexible sheet layer 2a, 2 …… Multilayer coextrusion blocking laminated film layer 3a, 3 …… Adhesive layer 4a, 4 …… Ethylene acrylate resin film layer 5a, 5 …… Thermoplastic resin film layer 6a, 6 ... two-layer coextrusion inflation film 7a, 7 ... middle layer 8a, 8 ... three-layer coextrusion inflation film 9a, 9 ... four-layer coextrusion inflation film a;

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Claims (1)

[Claims] 1. A pseudo-adhesive layer comprising two layers of ethylene acrylic acid ester resin film layers, which are inner layers of a multi-layer coextrusion film, attached by blocking, and a light-reflecting flexible sheet layer. Packaging material