JPH0615229B2 - Packaging material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a packaging material suitable for packaging relatively heavy items, such as movie roll films, among various photographic light-sensitive materials, light-sensitive substances, electronic parts and the like. It is about.

[Conventional technology]

In general, as a packaging material for high-tech products such as photographic light-sensitive materials, in addition to completely blocking light, gas barrier properties, moisture resistance, physical strength (breaking strength, tear strength, impact drilling strength, gelbotest strength, abrasion strength) Etc.), heat sealing suitability (heat sealing strength, cut sealing property, hot tack property, foreign substance sealing property, etc.), antistatic property, lubricity, low dust generation property, flatness, etc. To be done.
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 substance, and has already disclosed what has improved physical strength 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. The double-layered uniaxial molecular orientation film is the thickness of the laminated film that is heat-melt-bonded on both sides of the foam with or without the heat-melting adhesive layer so that the molecular orientation axes intersect at an angle of 30 degrees or more. Is a laminated film that has excellent impact hole ake strength and gelbotest strength compressed to a thickness of 40 to 85% of the theoretical sum of each layer (residual thickness ratio), and has a small curl. Has already been disclosed (Japanese Patent Laid-Open No. 59-201848).

[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.

Further, when a co-extruded T-die film, an inflation film, or the like is used as a laminated film having a plurality of layers laminated with an adhesive layer, trimming loss is large and uneconomical.

An object of the present invention is to solve the above problems and to provide a packaging material which is flexible, has a large physical strength, and has a small curl.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention is intended to perform pseudo-adhesion by blocking which was conventionally regarded as a failure without using an adhesive layer, and in particular, an ethylene vinyl acetate-based copolymer resin film layer having a predetermined composition. The present invention has been completed by finding that the physical strength is high and the occurrence of blocking is large.

More specifically, it contains an ethylene vinyl acetate-based copolymer resin film layer having a vinyl acetate content of 5% by weight or more, a light-shielding substance, a lubricant, and an ethylene copolymer resin of 10% by weight or more, and has a sliding angle of 6 to 30. Two multi-layered coextrusion blown films having a thermoplastic resin film layer having a certain degree are pseudo-bonded by blocking the ethylene vinyl acetate copolymer resin film layer.

A typical packaging material of the present invention has two layers of ethylene vinyl acetate-based copolymer resin film layers in which an inner layer of a multi-layer coextrusion blown film is pseudo-adhered by blocking.

This ethylene vinyl acetate-based copolymer resin film layer,
It is not completely bonded and fixed as if it was bonded with an adhesive layer, but it is pseudo-bonded in a somewhat flexible state by blocking without using any adhesive to improve physical strength and prevent curling. .

This ethylene vinyl acetate-based copolymer resin film layer,
The vinyl acetate content is 5% by weight or more. If it is less than 5% by weight, blocking is less likely to occur and it is close to that of polyethylene resin, and layer peeling is likely to occur during bag making and the like.

For pseudo-adhesion of the ethylene vinyl acetate copolymer resin film layer by blocking, for example, when forming a multilayer coextrusion inflation film by a multilayer coextrusion inflation method, a new nip roll for take-up or a subsequent stage of the take-up nip roll is newly added. This is performed by pressing the ethylene vinyl acetate-based copolymer resin film layer with the provided pressure roll. 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 lamination method, an outside die lamination method, and a laminar flow supply method. Is preferable because of its high interlayer adhesion.

In the case of a laminated film in which the ethylene vinyl acetate-based copolymer resin film layer of the inner layer of the multi-layer coextrusion inflation film is pseudo-adhered by blocking, there is no ear loss of the laminated film laminated by the conventional adhesive layer, and the inflation film is formed. At the same time, a blocked laminated film can be produced, so that the film can be effectively used and is stable, and wrinkles, melt fracture, etc. hardly occur, and the film formability is good.

On the outside of the ethylene vinyl acetate copolymer resin film layer, a thermoplastic resin film layer having a predetermined composition is laminated by a coextrusion inflation film molding method directly or via an intermediate layer.

The thermoplastic resin film layer contains 10% by weight or more of a light-shielding substance, a lubricant and an ethylene copolymer resin, and has a sliding angle of 6 to 30 degrees.

The light-shielding substance is 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 viewpoint of quality, cost, light-shielding ability, etc., color pigments that easily absorb or reflect light, especially various black pigments such as carbon black, graphite, aniline black, and silver-colored aluminum powder and aluminum paste are preferred. Those from which low volatile substances have been 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 substance may be a powdery colorant, a paste colorant, a wet colorant, a masterbatch, a dye / pigment, a colored pellet, or the like, depending on the resin used, the machine used, the cost, etc.

When used as a packaging material for various photosensitive materials, particularly various photographic photosensitive materials, furnace carbon black having an average particle size of 200 μ or less is preferable and expensive in terms of securing light-shielding properties, improving cost and physical strength. As the light-shielding substance having an antistatic effect, acetylene carbon black, Ketjen carbon black, graphite and the like are preferable, and in particular, a plate-shaped (or scale-shaped) light-shielding substance and a spherical (or granular) light-shielding substance are mixed. Are preferable in terms of improving dispersibility. It is also preferable to mix two or more light-shielding substances according to the required characteristics, if necessary. Even in this case, carbon black with an average particle size of 200μ or less
It is preferable to include ^two laminated film of 0.5g / m ² ~50g / m. On the other hand, among these carbon blacks, pH of 5
9. Average particle size of 10-120μ is preferable, especially pH
Furnace carbon black having an average particle size of 6 to 9 and an average particle size of 50 μm or less is preferable. By using such a pH and particle size, fog is less likely to occur, the increase or decrease in photosensitivity is less likely to occur, the light-shielding ability is large, and lumps
It is possible to obtain a packaging material that has various advantages such as pinholes that are unlikely to occur due to a fisheye, a fisheye, or the like, and that has improved physical strength and improved heat sealability.

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, prevention of contamination of the workplace, and the like.

Next to the carbon black, a metal powder that is preferable as a light-shielding substance will be described.

This metal powder is a light-reflecting light-shielding substance and gives a silver-colored, highly commercialized appearance, and is excellent in many points such as moisture resistance, antistatic property, and gas barrier property.

As the metal powder, a substance obtained by removing a low volatile substance from aluminum powder or aluminum paste and kneading with a thermoplastic resin is particularly preferable.

Here, the aluminum paste means, when an aluminum powder is produced by a known method such as a ball mill method, a stamp mill method or an atomizing method, mineral spirits and a small amount of higher fatty acids such as stearic acid or oleic acid and higher fatty acid derivatives It was made into a paste in the presence. In the present invention, this aluminum paste is heat-kneaded with a thermoplastic polyolefin resin (various polypropylene resins, various polyethylene resins, EVA resin, EEA resin, EAA resin, etc.) or another thermoplastic resin to obtain a low volatile substance (predominantly It is preferable to use a material obtained by heating and / or removing a strong mineral spirit) with a vacuum pump or the like as an aluminum paste compound resin or an aluminum paste masterbatch resin.

The aluminum powder is not only powdered by molten aluminum and atomizing method, granulation method, rotary disc dropping method, evaporation method, etc., but aluminum foil is crushed by a ball mill method, a stamp mill method or the like into flakes. Including things. Since the aluminum powder alone is unstable, various known treatments such as coating the surface of the aluminum powder with a higher fatty acid to render it inactive are performed.

Instead of the light-shielding substance or in combination with the light-shielding substance, silica, diatomaceous earth, talc, calcium silicate,
Aluminum silicate, magnesium silicate, calcium carbonate, higher fatty acid polyvinyl ester, n-octadecyl urea, dicarboxylic acid ester amide, N, N'-dioleyl oxamide and the like may be added to prevent blocking of the outer layer.

The representative types of the lubricants and their manufacturer names are described below, but the present invention is not limited to these.

(1) Silicone-based lubricants; various grades of dimethylpolysiloxane (Shin-Etsu Silicone, Toray Silicone), etc. (2) Oleic acid amide-based lubricants: Armoslip CP (Lion Akzo), Neutron (Nippon Seika), Neutron E -18 (Nippon Seika), Amide O (Nitto Kagaku),
Alflo E-10 (Nippon Yushi), Diamond O-200
(Nippon Kasei), Diamid G-200 (Nippon Kasei), etc. (3) Elucic acid amide lubricants; Alfuro-P-10 (Nippon Yushi), Neutron S (Nippon Seika), etc. (4) Stearic acid amide Lubricant: Alflo S-10 (Nippon Yushi), Neutron 2 (Nippon Seika), Diamond
200 (Nippon Kasei) etc. (5) Bis fatty acid amide lubricants; Bisamide (Nippon Kasei), Diamid 200 bis (Nippon Kasei), Armowax EBS (Lion Akzo), etc. (6) Alkylamine lubricants; Eretro stripper -TS
-2, Electrostripper-TS-3 (Kao soap) and the like.

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.
Therefore, not only the single addition but also two types may be used in combination.
The fatty acid amide-based lubricant preferred in the present invention has 8 to 50 carbon atoms.
And particularly preferably 15 to 35.

The ethylene copolymer resin contained in the thermoplastic resin film layer is ethylene-propylene copolymer resin, L-LDP.
E resin, EEA resin, EMA resin, EVA resin, EAA
Resin or the like can be used, and the content is 10% by weight or more. If it is less than 10% by weight, the delamination strength including a large amount of the light-shielding substance and the lubricant is small, and the physical strength is greatly reduced.

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 has become.

This sliding angle is the angle from the horizontal plane at which the film contact surface starts to slide when the film layer is attached to a solid substance, and is measured by, for example, the test method described later.

When the slip angle is less than 6 degrees, slipping occurs when winding the laminated film and winding deviation occurs, which is not practical. Also, a package using such a laminated film cannot be stacked. On the other hand, if the slip angle exceeds 30 degrees, wrinkles and streaks are generated during film formation, and troubles occur in the process of packaging using such a laminated film, which is not practical.

The multilayer coextrusion blown film layer has an ethylene vinyl acetate copolymer resin film layer and a thermoplastic resin film layer, and an intermediate layer may be laminated between them.

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.

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 an inner sticking of a light-chamber light-shielding magazine, an inner bag, a leader paper, and the like.

The method for bag making 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, since the ethylene vinyl acetate-based copolymer resin film layers located inside are pseudo-adhered to each other by blocking, the ethylene-vinyl acetate-based copolymer resin film layers are completely integrated and fixed. Instead, it is pseudo-bonded with some elasticity to improve shock buffering force and tear strength and reduce curl. Further, the thermoplastic resin film layer improves the film moldability and blocks the bad odor of the ethylene vinyl acetate copolymer resin film layer to prevent it from being exposed to the outside.

〔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 composed of four layers of an ethylene vinyl acetate-based copolymer resin film layer 1.1 which is an inner layer of a multi-layer coextrusion blown film and a thermoplastic resin film layer 2.2 which is an outer layer of the film. Vinyl acetate copolymer resin film layer 1 and thermoplastic resin film layer 2
Is a two-layer coextrusion film 3 formed by a circular die two-layer coextrusion inflation film molding machine. The ethylene vinyl acetate-based copolymer resin film layers 1 and 1, which are the inner layers, have a pseudo adhesive layer adhered 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 2a containing a light-shielding substance is used as the outer layer of the multilayer coextrusion inflation film 3a 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 2a and the ethylene vinyl acetate-based copolymer resin film layer 1a having a light shielding property are used.

The packaging material of FIG. 4 is the same as the packaging material of FIG. 1 except that the ethylene vinyl acetate-based copolymer resin film layer 1a having a light shielding property is used.

The packaging material shown in FIG. 5 is a multi-layer coextrusion blown film including an inner layer of ethylene vinyl acetate-based copolymer resin film layer 1.1, an intermediate layer of 4.4, and an outer layer of a thermoplastic resin film layer of 2.2. The ethylene vinyl acetate-based copolymer resin film layer 1, the intermediate layer 4 and the thermoplastic resin film layer 2 are composed of three layers, and the three layer coextruded film 5 is formed by the round die method three layer coextrusion inflation film molding method. Is. A pseudo adhesive layer is formed between the ethylene vinyl acetate copolymer resin film layers 1 and 1 by blocking.

In the packaging material of FIG. 6, except that each layer has a light-shielding property,
It is the same as the packaging material of FIG.

The packaging material of FIG. 7 is an ethylene vinyl acetate-based copolymer resin film layer 1.1, an intermediate layer 41.41, which is an inner layer in a multilayer coextrusion blown film, and an intermediate layer 42a. The multi-layer coextrusion blown film comprises outer layers of light-shielding thermoplastic resin film layers 2a and 2a, and these ethylene vinyl acetate copolymer resin film layer 1, intermediate layers 41 and 42a, and thermoplastic resin film layer. Reference numeral 2a is a four-layer coextrusion film 6a formed by a circular die method four-layer coextrusion inflation film molding method. A pseudo adhesive layer is formed between the ethylene vinyl acetate copolymer resin film layers 1 and 1 by blocking.

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

Inventive Product I Inventive Product I corresponds to the layer structure of FIG.

The ethylene vinyl acetate-based copolymer resin film layer 1 has a vinyl acetate content (saponification method) of 14% by weight and MFR (ASTM D
-1238 modified) is 3.5g / 10 minutes, density (ASTM D-1505) is 0.93g / cm
³ , EVA resin having a Vicat softening point of 68 ° C., 70% by weight and ethylene copolymer resin of ethylene and octene-1 having a density of 0.920 g / cm ³ , MI of 2 g / 10 minutes and a Vicat softening point of 9
Consisting of 30% by weight of L-LDPE resin at 6 ℃, thickness 25μm
Is formed in.

The thermoplastic resin film layer 2a has a density of 0.954 g / cm ³ , MI
Is 1.1g / 10 minutes, HDPE resin 20 with a Vicat softening point of 126 ° C
% By weight, an ethylene copolymer resin of ethylene and 4-methylpentene-1 having a density of 0.920 g / cm ³ and an MI of 2.1 g / 1.
0 minutes, L-LDPE resin with a Vicat softening point of 100 ° C is 76.9
Consists of 5% by weight, 3% by weight of carbon black and 0.05% by weight of oleic acid amide, with a thickness of 25 μm and a sliding angle of 11
Is formed every time.

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

The ethylene vinyl acetate-based copolymer resin film layer 1a has a vinyl acetate content (silicidation method) of 19% by weight and an MFR of 2.5 g / 1.
0 minutes, density 0.94 g / cm ³ , 60% by weight of EVA resin with Vicat softening point 64 ° C, ethylene and butene-1 ethylene copolymer resin density 0.890 g / cm ₃ , MI 1 g / 10 minutes , 38% by weight of L-LDPE resin having a Vicat softening point of 58 ° C. and 2% by weight of carbon black, and has a thickness of 25 μm.

The thermoplastic resin film layer 2a 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 ethylene vinyl acetate-based copolymer resin film layer 1a has a vinyl acetate content (silicidation method) of 14% by weight and an MFR of 1.4 g / 1.
EVA with 0 minutes, density 0.93 g / cm ³ , Vicat softening point 70 ° C
Resin 60% by weight and ethylene-butene-1 ethylene copolymer resin having a density of 0.906 g / cm ³ , MI of 0.8 g / 10 min, Vicat softening point of 84 ° C, 37% by weight of L-LDPE resin and carbon It is composed of 3% by weight of black and has a thickness of 25 μm.

The thermoplastic resin film layer 2a 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.

The ethylene vinyl acetate-based copolymer resin film layer 1a is made of the same resin composition as the product II of the present invention and is formed to a thickness of 30 μm.

The thermoplastic resin film layer 2a has a density of 0.923 g / cm ³ , MI
Is 2.4g / 10min, LDPE resin 5 with a Vicat softening point of 92 ℃
% HDPE resin with a density of 0.964 g / cm ³ , MI of 0.4 g / 10 min, Vicat softening point of 128 ° C., and carbon black of 3% by weight, and a thickness of 20 μm and a sliding angle of 9 Is formed every time.

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

The ethylene vinyl acetate-based copolymer resin film layer 1a has a vinyl acetate content (saponification method) of 19% by weight and an MFR of 2.5 g / 1.
EVA with 0 minutes, density 0.94 g / cm ³ , Vicat softening point 64 ° C
60% by weight of resin, ethylene is an ethylene copolymer resin of 4-methylpentene-1, and the density is 0.920 g / cm ³ , and MI is
2.1g / 10min, L-LDPE resin with Vicat softening point of 100 ℃
Consisting of 38% by weight and 2% by weight carbon black, thickness 25
It is formed to a μm.

The thermoplastic resin film layer 2a is the same as the product III of the invention.

Comparative product I A layer formed to have a thickness of 50 μm with the same resin composition as the ethylene vinyl acetate copolymer resin film layer 1a of the invention product IV,
A packaging material for a two-layer coextruded film, which comprises the thermoplastic resin film layer 2a of Product IV of the present invention and a layer having the same resin composition and having a thickness of 50 μm.

In the above-mentioned invention products, the measuring method of each property of the L-LDPE resin 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 (℃) .

On the other hand, a part of the film to be tested was similarly cut and adhered to the inclined surface, the film surface of the block was placed on the inclined surface, the inclination angle of the inclined surface was changed, and the block began to slide. The angle θ was read.

〔The invention's effect〕

In the present invention, pseudo-adhesion is achieved by blocking, and since the ethylene vinyl acetate-based copolymer resin film layer is used,
It is flexible and physical strength such as tear strength, gelbotest strength, burst strength, impact drilling strength, etc. is significantly improved, and curling does not occur.Because a laminated film using an adhesive can be omitted, bonding equipment etc. can be omitted, so it is inexpensive. Can be provided. Also, the EVA resin film single-layer moldability, which has been a problem in the past, and blocking and bad odor when rolled can be improved.

[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. 1,1a …… Ethylene vinyl acetate copolymer resin film layer (inner layer) 2,2a …… Thermoplastic resin film layer (outer layer) 3,3a …… Two-layer coextrusion inflation film 4,4a …… Intermediate layer 5 , 5a: 3-layer co-extrusion inflation film 6,6a: 4-layer co-extrusion inflation film a: Shows that it has a light-shielding property.

Claims (1)

[Claims] 1. A laminated packaging material comprising a pseudo-adhesive layer obtained by adhering two layers of an ethylene vinyl acetate-based copolymer resin film, which is an inner layer of a multilayer coextruded film, by blocking.