TW201800225A - Multilayer resin film and molded container including a resin layer made of an olefin-based resin and serving as a water vapor barrier resin layer and a resin layer made of a styrene-based resin - Google Patents

Abstract

The present invention provides a multilayer resin film, in which a resin layer made of an olefin-based resin and serving as a water vapor barrier resin layer is laminated via a bonding layer on both side surfaces of an oxygen barrier resin layer, and a resin layer made of a styrene-based resin is laminated via a bonding layer on one side of the water vapor barrier resin layer. The water vapor barrier resin layer has a total thickness of 50 to 300 [mu]m, the styrene-based resin layer has a thickness of 200 to 900 [mu]m and the difference of the oxygen transmission rates before and after being placed in a high-temperature, high-humidity environment is maintained at 1.0 cc/m2 day or less. This multilayer resin film has excellent thermoformability, oxygen barrier properties, and water vapor barrier properties.

Description

Multi-layer resin film and molded container

The invention relates to a multilayer resin film with high barrier properties and a molding container obtained by using the film.

Containers for traditional refreshing beverages, fruit drinks, and foods are made of polystyrene resins with excellent thermoformability and rigidity. In recent years, multilayer resin films and multilayer containers made from them have been promoted. This type of product uses a polystyrene resin layer as the outermost layer, with a bonding layer such as a modified olefin resin interposed therebetween, and then provides ethylene- The vinyl alcohol copolymer resin layer has a function of blocking oxygen, thereby preventing the content from being degraded due to oxidation (see Patent Document 1).

In addition, Patent Document 2 discloses a gas barrier film, which is characterized by using a gas barrier material containing a silicon-containing polymer and a thermoplastic resin, so that the glass transition temperature of the thermoplastic resin reaches 100 ° C or higher, and a plasma is applied to the gas barrier material. In the injection treatment, the silicon-containing polymer is a polysilazane compound, and the thermoplastic resin is at least one selected from the group consisting of a polycarbonate resin, a cycloolefin resin, and a polyfluorene resin.

In addition, an optical resin film having barrier properties against solvents such as oxygen, water vapor, and moisture, and solvent resistance has also been disclosed (see Patent Document 3).

Specifically, it is characterized in that a coating film containing a polysilazane inorganic polymer as a main component is formed on at least one surface of an optically transparent resin film, and then the film is heated. The curing process is performed to provide a gas barrier layer having a thickness of about 0.02 to 5 μm.

In general, when transporting containers that hold food, in order to avoid damage to the container due to vibration and external temperature environment during transportation, and to prevent the quality of the food in the container from being lowered, multiple containers are stacked in the package for protection. , Or by a temperature-managed transport method. At the same time, they are often temporarily stored in a storage warehouse in the same form after transportation. However, there are very few packaging or handling methods that can also manage humidity.

On the other hand, in order to prevent the deterioration of the quality due to the oxidation of the contents, the resin used as the oxygen barrier layer provided in the container structure has a problem that the barrier property of the oxygen barrier layer resin is reduced due to the influence of humidity. . In addition, because the oxygen barrier resin is hygroscopic, the moisture absorbed when it is heated to form a container will cause air bubbles, which will cause the appearance of the container after molding, such as granular bubbles, and other problems such as perforations.

Therefore, the barrier film described in Patent Documents 1-2 does not take into account the effects of humidity during transportation and storage described above. If a container formed using the film is left in a high humidity environment for a long time, its original barrier properties may not be maintained. Therefore, it is impossible to prevent the problem of quality degradation caused by oxidation, or the above-mentioned appearance defects may occur.

On the other hand, the barrier film described in Patent Document 3 is to prevent the oxygen barrier layer from being affected by humidity on the surface of the resin film by applying a coating film having gas or moisture barrier properties to both sides of the resin film. The barrier properties of the resin are reduced due to moisture absorption.

However, when a resin film having such a thin coating film is used to mold a container for food or beverage, a deep-draw stamping process is usually required, which causes cracks (openings) in the coating film during the deep-draw thermoforming process. Once the above-mentioned crack (opening) exists in the container thus formed, Oxygen or moisture intrudes through this nick (opening) and decreases the barrier properties.

Patent Document 1 Japanese Patent Laid-Open No. 11-58619

Patent Document 2 PCT International Patent Publication No. WO2013175911A1

Patent Document 3 Japanese Patent Laid-Open No. 8-169078

The present invention is a product developed after considering the above problems, and provides a multilayer resin film with high barrier properties and a molding container manufactured by using the film. The water vapor barrier properties are formed on both surfaces of an oxygen barrier resin layer. The resin layer has excellent oxygen barrier properties and water vapor barrier properties. At the same time, it can maintain high oxygen barrier properties even in high humidity environments.

A multilayer resin film of the present invention has a resin layer composed of an olefin resin serving as a water vapor barrier resin layer laminated on both sides of an oxygen barrier resin layer via a bonding layer, and water vapor barrier on one surface. A resin layer made of a styrenic resin is laminated on the flexible resin layer, wherein the total thickness of the water vapor barrier resin layer is 50 to 300 μm, and the thickness of the styrenic resin layer is 200 to 900 μm.

In addition, in the multilayer resin film having the above-mentioned structure, the difference in oxygen transmission rate before and after being placed in a high-temperature and high-humidity environment is maintained at 1.0 cc / m ² ‧day or less.

Further, in the multilayer resin film having the above configuration, the difference in the oxygen transmission rate is maintained below 5.0 cc / m ² ‧day, and the water vapor transmission rate thereof is maintained below 3.0 g / m ² ‧day.

Therefore, the multilayer resin film having the above-mentioned structure has excellent oxygen barrier properties and water vapor barrier properties, and can maintain high oxygen barrier properties even in a high humidity environment.

In addition, in the multilayer resin film having the above configuration, the thickness of the oxygen-barrier resin layer is set to 10 to 50 μm. When the multilayer resin film having such a structure is used for molding, the quality of the oxygen-barrier resin layer can be prevented from being degraded due to the thinness of the oxygen-barrier resin layer, thereby ensuring the oxygen-barrier performance and preventing the oxygen-barrier resin layer. Too thick to cause resin dents during container molding.

Moreover, in the multilayer resin film of the said structure, the thickness of each bonding layer is set to 10-50 micrometers, respectively. With the multilayer resin film configured in this way, it is possible to prevent insufficient interlayer bonding strength from being obtained because the bonding layer is too thin, and it is also possible to prevent resin dents that are generated when the container is formed because the bonding layer is too thick.

In the multilayer resin film having the above-mentioned configuration, the styrene-based resin layer is formed of a styrene-based resin containing a butadiene rubber component in a mass percentage of 4 to 8%. When the multilayer resin film having such a structure is used for molding, it can prevent the container from having insufficient strength due to the low content of the butadiene rubber component, and can also prevent the use of a hot plate due to the excessive content of the butadiene rubber component. Defects such as hot plate adhesion that occur during thermoforming.

Furthermore, in the multilayer resin film having the above configuration, the thickness of the multilayer resin film is 500 to 1200 μm. By adopting the multilayer resin film having such a structure, it is possible to prevent insufficient strength of the container after thermoforming caused by the multilayer resin film being too thin, and it is also possible to prevent heat from being sufficiently transmitted in the thickness direction of the film during thermoforming caused by the multilayer resin film being too thick, which may possibly A molding defect occurs and the manufacturing cost of the container becomes high.

The present invention also provides a molded container formed by using the multilayer resin film configured as described above. The molded container thus obtained has excellent oxygen barrier properties and water vapor barrier properties, and can maintain high oxygen barrier properties even in a high-humidity environment. Prevents the quality degradation caused by the oxidation of the articles in the molded container, and the moldability of the molded container is also good.

10a, 10b‧‧‧‧Water vapor barrier resin layer

11a, 11b, 11c‧‧‧ bonding layer

12‧‧‧ oxygen barrier resin layer

13‧‧‧styrene resin layer

20‧‧‧formed container

FIG. 1 is a schematic longitudinal sectional view of a multilayer structure of a multilayer resin film according to an embodiment of the present invention.

FIG. 2 is a schematic longitudinal sectional view of a multilayer structure of a multilayer resin film according to another embodiment.

FIG. 3 is a schematic perspective view of a molded container according to an embodiment of the present invention.

Hereinafter, the structure of a multilayer resin film according to an embodiment of the present invention and a molding container formed by molding the multilayer resin film will be described in detail.

As shown in FIG. 1, the multilayer resin film according to an embodiment of the present invention has a structure in which a water vapor barrier resin layer as the outermost layer is laminated on both sides of the oxygen barrier resin layer 12 via bonding layers 11 a and 11 b, respectively. 10a and the water vapor barrier resin layer 10b as an intermediate layer, a styrene resin layer 13 as a base material layer is laminated on the water vapor barrier resin layer 10b via a bonding layer 11c. The total thickness of the water vapor barrier resin layers 10a and 10b in the outermost layer and the intermediate layer is set to 50 to 300 μm in total, and the thickness of the styrene-based resin layer 13 in the base layer is set to 200 to 900 μm.

The olefin-based resin used in the water vapor-barrier resin layers 10a and 10b includes, but is not limited to, olefin homopolymers having a carbon number of about 2 to 8 such as ethylene, propylene, and n-butene. The water vapor barrier resin layers 10a and 10b are formed as the outermost layer and the intermediate layer of the multilayer resin film. Unless otherwise specified, the outermost layer is set to be a layer in contact with the contents, but it is not particularly limited.

The thickness of the water vapor barrier resin layer 10a as the outermost layer is set to be the same as that of the water vapor barrier resin layer 10b as the intermediate layer, or it is set to be thicker than the water vapor barrier resin layer 10b as the intermediate layer. The thickness of the water vapor barrier resin layer 10b in the intermediate layer is set to 200 μm or more, and the total thickness of the water vapor barrier resin layers 10a and 10b in the outermost layer and the intermediate layer is set to 50 to 300 μm (preferably 70 to 200 μm). If the total thickness is less than 50 μm, an excessively thin portion may appear after molding, so that the water vapor barrier property cannot be fully exerted. If the total thickness exceeds 300 μm, the optimal temperature range during thermoforming will be reduced, and Stable molding may not be possible.

The resin constituting the bonding layers 11a, 11b, and 11c is preferably a modified olefin polymer. Representative examples of the modified olefin polymer constituting the bonding layer include the following: namely, olefin homopolymers having a carbon number of about 2 to 8 such as ethylene, propylene, and n-butene; and these olefins and ethylene and propylene Other olefins or vinyl acetates with a carbon number of about 2 to 20, such as n-butene, isopentene, n-pentene, 4-methylpentene-1, 1-hexene, 1-octene, n-decene, etc. Olefin resins such as esters, vinyl chloride, acrylic acid, 2-methacrylic acid, acrylate, methyl methacrylate, and copolymers of ethylene compounds such as styrene; or ethylene-propylene copolymers, ethylene-propylene-diene trienes Olefin rubbers such as meta-copolymers, ethylene-1-butene copolymers, and propylene-1-butene copolymers are compatible with acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, maleic acid, fumaric acid, and itaconic acid Unsaturated carboxylic acids such as citraconic acid, tetrahydrophthalic acid, or derivatives of carboxylic acid halides, fluorenamines, fluorenimines, anhydrous substances, esters, etc. (specifically, malondichloride, maleimide , Anhydrous maleic acid, anhydrous citraconic acid, monomethyl maleate, dimethyl maleate, maleic acid shrinkage ) Modifying substance under graft reaction conditions to give the ester oil and the like.

As the modified olefin polymer, an unsaturated carboxylic acid or an anhydride thereof is used, and in particular It is preferably an ethylene-based resin, propylene-based resin, ethylene-propylene, or n-butene copolymer rubber modified by maleic acid or its anhydrous substance.

The thicknesses of the bonding layers 11a, 11b, and 11c made of a modified olefin polymer are set to 10 to 50 μm (preferably 20 to 40 μm). When the thickness is less than 10 μm, sufficient interlayer bonding strength may not be obtained. In addition, when the thickness is more than 50 μm, resin dents may occur when the thermoformed container is pressed.

As the oxygen-barrier resin constituting the oxygen-barrier resin layer 12, representative materials include, but are not limited to, ethylene-vinyl alcohol copolymer resin, polyamide resin, and the like. Among these, an ethylene-vinyl alcohol copolymer resin is preferable from the viewpoint of processability and moldability.

The ethylene-vinyl alcohol copolymer resin is usually obtained by saponifying an ethylene-vinyl acetate copolymer. In order to have oxygen barrier properties, processability, and moldability, the ethylene content should be 10 to 65 mol% (preferably 20 to 50 mol). %), And the degree of saponification should be above 90% (preferably above 95%).

Examples of the polyamidoresin resin include: caprolactam, azatridecane-2-one, and the like; and 6-aminohexanoic acid, 11-aminoundecanoic acid, Amino acid ester polymers such as 12-aminododecanoic acid; 1,6-hexanediamine, 1,10-diaminodecane, dodecane diamine, 2,2,4- or 2,4,4 -Fatty diamines such as trimethylhexadiamine, alicyclic amines such as 1,3- or 1,4-bis (aminomethyl) cyclohexane, 4,4'-diaminodicyclohexylmethane, etc. Diamine units such as aromatic diamines such as xylylenediamine and p-xylylenediamine, and alicyclic carboxylic acids such as aliphatic carboxylic acids such as adipic acid, suberic acid, and sebacic acid, and cyclohexanedicarboxylic acid. Polycondensates formed from carboxylic acid units such as aromatic carboxylic acids such as acids, terephthalic acid, and isophthalic acid; and copolymers of the foregoing.

Specific examples of the polyamide resin include nylon 6, nylon 9, nylon 11, nylon 12, Nylon 66, nylon 610, nylon 611, nylon 612, nylon 6T, nylon 6I, nylon MXD6, nylon 6/66, nylon 6/610, nylon 6 / 6T, nylon 6I / 6T, etc., among which nylon 6, nylon MXD6 are the most popular good.

The thickness of the oxygen-barrier resin layer 12 is set to 10 to 50 μm (preferably 20 to 40 μm). If the thickness is less than 10 μm, the oxygen barrier performance of preventing the quality of the contents of the molded container from being deteriorated due to oxidation may not be achieved. In addition, if the thickness is more than 50 μm, resin dents may occur when the thermoformed container is pressed.

Examples of the styrene-based resin constituting the styrene-based resin layer 13 include styrene, 2-phenyl-1-propene, 4-methylstyrene, dimethylstyrene, and p-tert-butylbenzene. Homopolymers or copolymers of styrenic monomers such as ethylene and chlorostyrene; copolymers of these styrenic monomers and other monomers such as styrene-acrylonitrile copolymer (AS resin), or the aforementioned styrene Monomers and other polymers, such as graft polymerization in the presence of polybutadiene, polystyrene butadiene copolymer, polyisoprene, polychloroprene and other diene rubber polymers Graft polymers such as high impact polystyrene (HIPS resin), styrene-acrylonitrile graft polymer (ABS resin), and the like.

From the viewpoint of rigidity and moldability, polystyrene (GPPS resin) and high-impact polystyrene (HIPS resin) are preferred among the styrene resins.

The styrene-based resin preferably contains 4 to 8% by mass of the butadiene rubber component. The content of the butadiene rubber component can be adjusted by a simple method of mixing GPPS and HIPS, but it can also be adjusted at the stage of manufacturing HIPS. If the above-mentioned quality percentage is less than 4%, sufficient container strength may not be achieved. If the above-mentioned quality percentage is more than 8%, inconveniences such as hot-plate adhesion may occur especially when using hot-plate for thermoforming.

The styrene-based resin layer 13 may be added with colorants such as pigments and dyes, silicone oil or alkyl ester-based release agents, fiber-like reinforcing agents such as glass fiber, talc, kaolin, and the like, as long as they do not hinder the effects of the present invention. Granular lubricants such as cristobalite, salt compounds such as sulfonic acids and alkali metals, or antistatic agents such as polyglycols, ultraviolet absorbers and antibacterial agents. At the same time, the multilayer resin film of the present invention and the waste resin generated in the manufacturing process of the molded container may be mixed and used.

The thickness of the styrene-based resin layer 13 is set to 200 to 900 μm (preferably 300 to 700 μm). If the thickness is less than 200 μm, it may not be possible to achieve uniform thickness of each part of the container after molding, and excellent thermoformability may not be achieved. At the same time, if the thickness exceeds 900 μm, it is difficult to conduct heat sufficiently in the thickness direction of the film during thermoforming. Molding defects may occur.

Therefore, in one embodiment of the present invention, the layer structure of the multilayer resin film is the water vapor barrier resin layer / bonding layer / oxygen barrier resin layer / bonding layer / water vapor barrier resin layer / bonding layer / The structure of the styrenic resin layer is simply the outermost layer / bonding layer / oxygen barrier layer / bonding layer / intermediate layer / bonding layer / base material layer. At the same time, the base material layer composed of a styrenic resin may be formed by laminating a layer composed of the multilayer resin film of the present invention or a waste resin generated in the manufacturing process of a molding container and a layer of only a styrenic resin. .

The thickness of the multilayer resin film of the present invention is set to 500 to 1200 μm (preferably 700 to 1000 μm). If the thickness is less than 500 μm, the strength of the container after thermoforming may be insufficient. If the thickness exceeds 1200 μm, it is difficult to sufficiently conduct heat in the thickness direction of the film during thermoforming, and molding defects may occur. At the same time, the manufacturing cost of the container may become high.

The method for forming the multilayer resin film of the present invention is not particularly limited, and can be Use conventional methods. For example, a method of using four or more uniaxial extruders to melt extrude each raw resin and obtain a multilayer resin film through a feed-block and a T-die, or through a multi-runner die Method for obtaining a multilayer resin film and the like.

As shown in FIG. 3, a molded container 20 according to an embodiment of the present invention is formed by thermoforming a multilayer resin film of the present invention. Examples of the thermoforming method include a common vacuum forming method, a pressure forming method, a plunger assisting method in which a plunger is brought into contact with one side of a film, or a pair of male and female dies are brought into contact with both sides of a film to be formed. Counter-molding molding methods. But the method is not limited to this. Meanwhile, as a method of heating and softening the film before molding, non-contact heating using radiant heating by an infrared heater, or hot plate heating in which the film is brought into contact with the heated hot plate to soften it, can be used. heating method.

In addition, the molding temperature during thermoforming is reasonably set in consideration of the melting point of the resin, etc. However, if the film heating temperature is too low, the shape of the container after heating molding is insufficient, and if the film heating temperature is too high, it will cause adhesion. In the case of a hot plate or the like, it is necessary to set an appropriate temperature.

Examples and comparative examples will be listed below to further specifically describe the present invention, but the present invention is not limited to the scope of the examples and the like.

The resin raw materials used in the examples are shown below.

(1) Water vapor barrier resin layer

HDPE resin: "8050" (produced by Formosa Polypropylene Co., Ltd., MI: 6.0g / 10min. (190 ° C, 2.16kgf))

PP resin: "HJ730L" (produced by Samsung Total, MI: 5.0g / 10min (190 ° C, 2.16kgf), IsotacticHomoPP)

(2) Oxygen-barrier resin layer

Ethylene-vinyl alcohol copolymer (EVOH) "EVAL J171B" (Produced by Kuraray, MI: 1.7g / 10min (190 ° C, 2.16kgf), ethylene content 32mol%)

(3) Joint layer

Modified olefin polymer (modified PO) "MODIC F502C" (Mitsubishi Chemical Corporation, MI: 1.3g / 10min (190 ° C, 2.16kgf))

(4) Styrene resin layer

HIPS resin: "4241" (manufactured by Total Petrochemicals, MI: 4.0g / 10min. (200 ° C, 5.0kgf))

Moreover, in the Example, the multilayer resin film was heat-molded under the following conditions, and the container for buttermilk shown in FIG. 3 was obtained.

(1) Equipment: Vacuum pressure molding machine produced by Asano Research Institute

(2) Heater: Non-contact far-infrared heater

(3) Film surface temperature: Adjusted to an appropriate film surface temperature according to the composition of the film

The obtained multilayer resin film and container were evaluated by the following methods. The evaluation results are shown in Tables 1 and 2.

(1) Measurement of water vapor transmission rate

The water vapor transmission rate of the film was measured by the following method.

[Measurement method] According to GB / T 1037 standard

Equipment: W3 / 031 detection device produced by Labthink

Measurement conditions: 40 ℃ × 90% R.H.

The water vapor transmission rate was evaluated using the following criteria.

If the water vapor permeability of 3.0g / m ² ‧day less, the water vapor barrier property of the multilayer resin film passing water vapor transmission rate greater than 3.0g / m ² ‧day, the water vapor barrier multilayer resin film Failed.

(2) Measurement of oxygen transmission rate

The oxygen transmission rate of the film was measured by the following method. The oxygen transmission rate before and after being placed in the following high temperature and high humidity environment was measured.

[Measurement method] According to GB / T 1038 standard

Equipment: VAC-V1 detection device produced by Labthink

Measurement conditions: 23 ℃ × 65% R.H.

Sample setting: In view of the practicality of the container after molding, when setting the sample, make sure to face it so that oxygen can pass through the substrate layer side of the thin film sample.

〔Placed in high temperature and high humidity environment〕

Attach aluminum tape to the end of the film to eliminate the influence of water vapor permeation at the end of the film, and leave the end for 6 hours at 40 ℃ × 90% R.H. In a state where the end cannot contact the high temperature and high humidity environment. The oxygen transmission rate before and after being left in this environment was measured.

In addition, the following criteria were used to evaluate the oxygen transmission rate.

If the oxygen transmission rate is below 5.0 cc / m ² ‧day, the oxygen barrier properties of the multilayer resin film are acceptable. If the oxygen transmission rate is higher than 5.0 cc / m ² ‧day, the oxygen barrier properties of the multilayer resin film are unacceptable.

In addition, the following criteria were used to evaluate the difference in oxygen transmission rate before and after exposure to a high temperature and high humidity environment.

If the difference in oxygen transmission rate before and after being placed in a high-temperature and high-humidity environment is less than 1.0cc / m ² ‧day, then the oxygen barrier properties of the multilayer resin film are qualified. The difference in oxygen transmission rate before and after being placed in a high-temperature and high-humidity environment is higher than 1.0cc / At m ² ‧day, the oxygen barrier property of the multilayer resin film is unsatisfactory.

(3) Moldability

Using the mold for molding the container shown in FIG. 3, the moldability at the time of thermoforming was evaluated by the following criteria.

A: Good moldability

B: Some parts of the container are thin after molding

C: No formability such as a molding die was obtained. Or found the appearance defect.

<Example 1>

HDPE resin "8050" was used in the olefin resin by the feed-block method using three 45mm uniaxial extruder, one 65mm uniaxial extruder, and one 105mm uniaxial extruder. 100 μm of water vapor barrier resin layer 10/15 μm of bonding layer 11 a / 40 μm of oxygen barrier resin layer 12/15 μm of bonding layer 11 b / 35 μm of water vapor barrier resin layer 10 b / 15 μm of bonding layer 11 c / The styrene-based resin layer 13 is a multilayer resin film having a layer structure of 880 μm and a total thickness of 1100 μm (the total thickness of the water vapor barrier resin layer is 135 μm).

The water vapor transmission rate of the multilayer resin film obtained above was measured. As shown in Table 1, the water vapor transmission rate was 0.8 g / m ² ‧day. In addition, as a result of measuring the oxygen transmission rate, as shown in Table 1, the oxygen transmission rate before being placed in a high-temperature and high-humidity environment was 0.12cc / m ² ‧day, and the oxygen transmission rate after being placed in a high-temperature and high-humidity environment. The rate is 0.32cc / m ² ‧day, and the difference in oxygen transmission rate before and after being placed in a high temperature and high humidity environment is 0.20cc / m ² ‧day. In addition, the moldability of a container molded using the multilayer resin film was also evaluated, and the moldability was evaluated as A.

<Example 2>

In the same manner as in Example 1, 80 μm of the water vapor barrier resin layer 10/15 μm of the bonding layer 11 a / 15 μm of the oxygen barrier resin layer 12/15 μm of the bonding layer 11 b / 35 μm of the water vapor barrier resin layer 10 b / The bonding layer 11c is 15 μm / The styrene-based resin layer 13 has a layer structure of 900 μm, and the total thickness is 1100 μm (water vapor barrier resin laminate Multilayer resin film with a thickness of 115 μm).

The water vapor transmission rate of the multilayer resin film obtained above was measured. As shown in Table 1, the water vapor transmission rate was 1.1 g / m ² ‧day. In addition, as a result of measuring the oxygen transmission rate, as shown in Table 1, the oxygen transmission rate before being placed in a high-temperature and high-humidity environment was 0.21cc / m ² ‧day, and the oxygen transmission rate after being placed in a high-temperature and high-humidity environment. The rate is 0.35cc / m ² ‧day, and the difference in oxygen transmission rate before and after being placed in a high temperature and high humidity environment is 0.14cc / m ² ‧day. In addition, the moldability of a container molded using the multilayer resin film was also evaluated, and the moldability was evaluated as A.

<Example 3>

In the same manner as in Example 1, a water vapor barrier resin layer 10a was 65 μm / bonding layer 11a was 15 μm / oxygen barrier resin layer 12 was 30 μm / bonding layer 11 b was 15 μm / water vapor barrier resin layer 10b was 20 μm A multilayer resin film having a layer structure of 15 μm / the styrenic resin layer 13 and a bonding layer 11c of 740 μm and a total thickness of 900 μm (the total thickness of the water vapor barrier resin layer is 85 μm).

The water vapor transmission rate of the multilayer resin film obtained above was measured. As shown in Table 1, the water vapor transmission rate was 1.1 g / m ² ‧day. In addition, as a result of measuring the oxygen transmission rate, as shown in Table 1, the oxygen transmission rate before being placed in a high-temperature and high-humidity environment was 0.22cc / m ² ‧day, and the oxygen transmission rate after being placed in a high-temperature and high-humidity environment. The rate is 0.52cc / m ² ‧day, and the difference in oxygen transmission rate before and after being placed in a high temperature and high humidity environment is 0.30cc / m ² ‧day. In addition, the moldability of a container molded using the multilayer resin film was also evaluated, and the moldability was evaluated as A.

<Example 4>

In the same manner as in Example 1, 80 μm of the water vapor barrier resin layer 10/15 μm of the bonding layer 11 a / 15 μm of the oxygen barrier resin layer 12/15 μm of the bonding layer 11 b / 35 μm of the water vapor barrier resin layer 10 b The multi-layer resin film having a layer structure of 15 μm / the bonding layer 11c and a 200 μm layer of the styrene resin layer 13 and a total thickness of 400 μm (the total thickness of the water vapor barrier resin layer is 115 μm).

The water vapor transmission rate of the multilayer resin film obtained above was measured. As shown in Table 1, the water vapor transmission rate was 1.0 g / m ² ‧day. In addition, as a result of measuring the oxygen transmission rate, as shown in Table 1, the oxygen transmission rate before being placed in a high-temperature and high-humidity environment was 0.18cc / m ² ‧day, and the oxygen transmission rate after being placed in a high-temperature and high-humidity environment. The rate is 0.30cc / m ² ‧day, and the difference in oxygen transmission rate before and after being placed in a high temperature and high humidity environment is 0.12cc / m ² ‧day. In addition, the moldability of a container molded using the multilayer resin film was also evaluated, and the moldability was evaluated as A.

<Example 5>

In the same manner as in Example 1, 30 μm of water vapor barrier resin layer 10/15 μm of bonding layer 11a / 15 μm of oxygen barrier resin layer 12/15 μm of bonding layer 11b / 20 μm of water vapor barrier resin layer were obtained The / bonding layer 11c has a multilayer structure of 15 μm / the styrene resin layer 13 has a layer structure of 775 μm and a total thickness of 900 μm (the total thickness of the water vapor barrier resin layer is 50 μm).

The water vapor transmission rate of the multilayer resin film obtained above was measured. As shown in Table 1, the water vapor transmission rate was 1.5 g / m ² ‧day. In addition, as a result of measuring the oxygen transmission rate, as shown in Table 1, the oxygen transmission rate before being placed in a high-temperature and high-humidity environment was 0.22cc / m ² ‧day, and the oxygen transmission rate after being placed in a high-temperature and high-humidity environment. The rate is 0.58cc / m ² ‧day, and the difference in oxygen transmission rate before and after being placed in a high temperature and high humidity environment is 0.36cc / m ² ‧day. In addition, the moldability of a container molded using the multilayer resin film was also evaluated, and the moldability was evaluated as A.

<Example 6>

In the same manner as in Example 1, 200 μm of water vapor barrier resin layer 10 a / 15 μm of bonding layer 11 a / oxygen barrier resin layer 12 of 40 μm / 15 μm of bonding layer 11 b / 100 μm of water vapor barrier resin layer 10 b The / bonding layer 11c has a multilayer structure of 15 μm / the styrene-based resin layer 13 has a layer structure of 715 μm and a total thickness of 1100 μm (the total thickness of the water vapor barrier resin layer is 300 μm).

The water vapor transmission rate of the multilayer resin film obtained above was measured. As shown in Table 1, the water vapor transmission rate was 0.8 g / m ² ‧day. In addition, as a result of measuring the oxygen transmission rate, as shown in Table 1, the oxygen transmission rate before being placed in a high-temperature and high-humidity environment was 0.11cc / m ² ‧day, and the oxygen transmission rate after being placed in a high-temperature and high-humidity environment. The rate is 0.23cc / m ² ‧day, and the difference in oxygen transmission rate before and after being placed in a high temperature and high humidity environment is 0.12cc / m ² ‧day. In addition, the moldability of a container molded using the multilayer resin film was also evaluated, and the moldability was evaluated as A.

<Example 7>

For the olefin resin, a PP resin "HJ730L" was used, and other methods were the same as those in Example 1. A multilayer resin film having the same layer structure as in Example 1 was obtained.

The water vapor transmission rate of the multilayer resin film obtained above was measured. As shown in Table 1, the water vapor transmission rate was 0.6 g / m ² ‧day. In addition, as a result of measuring the oxygen transmission rate, as shown in Table 1, the oxygen transmission rate before being placed in a high-temperature and high-humidity environment was 0.15 cc / m ² ‧day, and the oxygen transmission rate after being placed in a high-temperature and high-humidity environment. The rate is 0.18cc / m ² ‧day, and the difference in oxygen transmission rate before and after being placed in a high temperature and high humidity environment is 0.03cc / m ² ‧day. In addition, the moldability of a container molded using the multilayer resin film was also evaluated, and the moldability was evaluated as A.

On the other hand, compared with Example 1, the total thickness of the water vapor barrier resin layer or the thickness of the styrene-based resin layer as the base material layer is reduced, or the water vapor barrier layer is formed by using a styrene-based resin layer. As a comparative example, the following modified examples were evaluated for their performance.

<Comparative example 1>

In the same manner as in Example 1, a water vapor barrier resin layer 10a was 30 μm / bonding layer 11a was 15 μm / oxygen barrier resin layer 12 was 40 μm / bonding layer 11b was 15 μm / water vapor barrier resin layer 10b was 100 μm The / bonding layer 11c has a multilayer structure of 15 μm / the styrene-based resin layer 13 has a layer structure of 975 μm and a total thickness of 1100 μm (the total thickness of the water vapor barrier resin layer is 40 μm).

Compared with Example 1, this comparative example is characterized by reducing the total thickness of the olefin-based resin layer.

As a result of measuring the water vapor transmission rate of the multilayer resin film obtained in this comparative example, as shown in Table 2, the water vapor transmission rate was 0.8 g / m ² ‧day. In addition, as a result of measuring the oxygen transmission rate, as shown in Table 2, the oxygen transmission rate before being placed in a high-temperature and high-humidity environment was 0.26cc / m ² ‧day, and the oxygen transmission rate after being placed in a high-temperature and high-humidity environment. The rate is 1.68cc / m ² ‧day, and the difference in oxygen transmission rate before and after being placed in a high temperature and high humidity environment is 1.42cc / m ² ‧day. In addition, the moldability of a container molded using the multilayer resin film was also evaluated, and the moldability was evaluated as A.

As a result of comparison with each evaluation standard, the difference in oxygen transmission rate before and after being placed in a high-temperature and high-humidity environment exceeds 1.0 cc / m ² ‧day, so it is unqualified, that is, it cannot be applied to a high-temperature and high-humidity environment.

<Comparative example 2>

In the same manner as in Example 1, 100 μm of water vapor barrier resin layer 10a / 15 μm of bonding layer 11a / 40 μm of oxygen barrier resin layer 12/15 μm of bonding layer 11b / 35 μm of water vapor barrier resin layer were obtained A multilayer resin film having a layer structure of 15 μm / the bonding layer 11c and a 180 μm layer of the styrene-based resin layer 13 and a total thickness of 400 μm (the total thickness of the water vapor barrier resin layer is 135 μm).

Compared with Example 1, this comparative example is characterized in that the thickness of the styrene-based resin layer as the base material layer is reduced.

As a result of measuring the water vapor transmission rate of the multilayer resin film obtained in this comparative example, as shown in Table 2, the water vapor transmission rate was 1.1 g / m ² ‧day. In addition, as a result of measuring the oxygen transmission rate, as shown in Table 2, the oxygen transmission rate before being placed in a high-temperature and high-humidity environment was 0.25 cc / m ² ‧day, and the oxygen transmission rate after being placed in a high-temperature and high-humidity environment. The rate is 0.43cc / m ² ‧day, and the difference in oxygen transmission rate before and after being placed in a high temperature and high humidity environment is 0.18cc / m ² ‧day. In addition, the moldability of a container molded using the multilayer resin film was also evaluated, and the moldability was evaluated as B.

As a result of comparison with each evaluation standard, the moldability was evaluated as B, and during use, cracks occurred in the thinned part of the container after molding, so that water vapor or oxygen easily penetrated and reduced the barrier properties.

<Comparative example 3>

In the same manner as in Example 1, 65 μm of styrene-based resin layer 10/15 μm of bonding layer 11a / 15 μm of oxygen-barrier resin layer 12/15 μm of bonding layer 11b / 20 μm of styrene-based resin layer 10 / bond The layer 11c has a multilayer structure of 15 μm / styrene-based resin layer 13 having a layer structure of 740 μm and a total thickness of 900 μm.

Compared with Example 1, this comparative example is characterized in that the water vapor barrier layer is formed of a styrene-based resin layer.

As a result of measuring the water vapor transmission rate of the multilayer resin film obtained in this comparative example, as shown in Table 2, the water vapor transmission rate was 4.5 g / m ² ‧day. In addition, as a result of measuring the oxygen transmission rate, as shown in Table 2, the oxygen transmission rate before being placed in a high-temperature and high-humidity environment was 0.22cc / m ² ‧day, and the oxygen transmission rate after being placed in a high-temperature and high-humidity environment. The rate is 2.56cc / m ² ‧day, and the difference in oxygen transmission rate before and after being placed in a high temperature and high humidity environment is 2.34cc / m ² ‧day. In addition, the moldability of a container molded using the multilayer resin film was also evaluated, and the moldability was evaluated as A.

As a result of comparison with various evaluation standards, its water vapor transmission rate exceeded 3.0g / m ² ‧day, and its difference in oxygen transmission rate before and after being placed in a high-temperature and high-humidity environment exceeded 1.0cc / m ² ‧day. That is not suitable for high temperature and high humidity environments.

<Comparative Example 4>

As shown in FIG. 2, in the same manner as in Example 1, 90 μm of water vapor barrier resin layer 10 a / 15 μm of bonding layer 11 a / 30 μm of oxygen barrier resin layer 12/15 μm of bonding layer 11 b / styrene The resin layer 13 is a multilayer resin film having a layer structure of 750 μm and a total thickness of 900 μm (the total thickness of the water vapor barrier resin layer is 90 μm).

Compared with Example 1, this comparative example is characterized in that an olefin-based resin layer as a water vapor-barrier resin layer is laminated on only one side of the oxygen-barrier resin layer with a bonding layer interposed therebetween.

As a result of measuring the water vapor transmission rate of the multilayer resin film obtained in this comparative example, as shown in Table 2, the water vapor transmission rate was 1.2 g / m ² ‧day. In addition, as a result of measuring the oxygen transmission rate, as shown in Table 2, the oxygen transmission rate before being placed in a high-temperature and high-humidity environment was 0.19cc / m ² ‧day, and the oxygen transmission rate after being placed in a high-temperature and high-humidity environment. The rate is 1.45cc / m ² ‧day, and the difference in oxygen transmission rate before and after being placed in a high temperature and high humidity environment is 1.26cc / m ² ‧day. In addition, the moldability of a container molded using the multilayer resin film was also evaluated, and the moldability was evaluated as A.

As a result of comparison with various evaluation standards, the difference in oxygen transmission rate before and after being placed in a high-temperature and high-humidity environment exceeds 1.0 cc / m ² ‧day, so it is unqualified, that is, it cannot be applied to a high-temperature and high-humidity environment.

<Comparative example 5>

In the same manner as in Example 1, a resin film having only a single layer of a styrene-based resin layer having a thickness of 900 μm was obtained.

Compared with Example 1, this comparative example is characterized by being composed of only a single layer of a styrene-based resin layer.

As a result of measuring the water vapor transmission rate of the multilayer resin film obtained in this comparative example, as shown in Table 2, the water vapor transmission rate was 6.5 g / m ² ‧day. In addition, as a result of measuring the oxygen transmission rate, as shown in Table 2, the oxygen transmission rate before being placed in a high-temperature and high-humidity environment was 335 cc / m ² ‧day, and the oxygen transmission rate after being placed in a high-temperature and high-humidity environment. It is 357cc / m ² ‧day, and the difference in oxygen transmission rate before and after being placed in a high temperature and high humidity environment is 22cc / m ² ‧day. In addition, the moldability of a container molded using the multilayer resin film was also evaluated, and the moldability was evaluated as A.

As a result of comparison with various evaluation standards, its water vapor transmission rate exceeds 3.0g / m ² ‧day, its oxygen transmission rate greatly exceeds 5.0cc / m ² ‧day, and its oxygen transmission rate before and after being placed in a high temperature and high humidity environment The difference exceeds 1.0cc / m ² ‧day, so it is unqualified, that is, it cannot be applied to high-temperature and high-humidity environments, and it has almost no barrier to water vapor and oxygen under normal circumstances.

According to the results of Examples 1-7 and Comparative Examples 1-5 described above, olefin-based resins which are used as water vapor-barrier resin layers are laminated on both surfaces of the oxygen-barrier resin layer through the bonding layer. A resin layer, and a resin layer made of a styrene resin is laminated on one surface of the olefin resin layer, and the total thickness of the water vapor barrier resin layer laminated on both sides of the oxygen barrier resin layer is 50 to 300 μm In addition, the multilayer resin film having a structure such that the thickness of the styrenic resin layer is 200 to 900 μm has a high barrier property against water vapor and oxygen. At the same time, the multilayer resin film is also used to form a molding container, and its moldability is also very good. .

Moreover, the multilayer resin film having the above-mentioned structure has a difference in oxygen transmission rate before and after being placed in a high-temperature and high-humidity environment of less than 1.0 cc / m ² ‧day.

Moreover, the multilayer resin film having the above structure has an oxygen transmission rate of 5.0 cc / m ² ‧day or less and a water vapor transmission rate of 3.0 g / m ² ‧ day or less.

Therefore, the multilayer resin film having the above-mentioned structure has excellent oxygen barrier properties and water vapor barrier properties, and can maintain high oxygen barrier properties even in a high-humidity environment.

In the multilayer resin film having the above structure, the thickness of the oxygen-barrier resin layer is set to 10 to 50 μm. When the multilayer resin film having such a structure is used for molding, the quality of the oxygen-barrier resin layer can be prevented from being degraded due to the thinness of the oxygen-barrier resin layer, thereby ensuring the oxygen-barrier performance and preventing the oxygen-barrier resin layer. Too thick to cause resin dents during container molding.

Moreover, in the multilayer resin film of the said structure, the thickness of each bonding layer is set to 10-50 micrometers, respectively. With the multilayer resin film configured in this way, it is possible to prevent insufficient interlayer bonding strength due to the too thin bonding layer, and to prevent the container from being caused by the bonding layer being too thick. Resin dents generated during molding.

In the multilayer resin film having the above-mentioned configuration, the styrene-based resin layer is formed of a styrene-based resin containing a butadiene rubber component in a mass percentage of 4 to 8%. When the multilayer resin film having such a structure is used for molding, it can prevent the container from having insufficient strength due to the low content of the butadiene rubber component, and can also prevent the use of a hot plate due to the excessive content of the butadiene rubber component. Defects such as hot plate adhesion that occur during thermoforming.

Furthermore, in the multilayer resin film having the above configuration, the thickness of the multilayer resin film is 500 to 1200 μm. By adopting the multilayer resin film having such a structure, it is possible to prevent insufficient strength of the container after thermoforming caused by the multilayer resin film being too thin, and it is also possible to prevent heat from being sufficiently transmitted in the thickness direction of the film during thermoforming caused by the multilayer resin film being too thick, which may possibly A molding defect occurs and the manufacturing cost of the container becomes high.

10a, 10b‧‧‧‧Water vapor barrier resin layer

11a, 11b, 11c‧‧‧ bonding layer

12‧‧‧ oxygen barrier resin layer

13‧‧‧styrene resin layer

Claims (8)

A multilayer resin film in which a water vapor barrier resin layer is laminated on both sides of an oxygen barrier resin layer with a bonding layer interposed therebetween, and a styrenic resin layer is laminated on one side of the water vapor barrier resin layer. The water vapor barrier resin layer is a layer composed of an olefin resin, and the total thickness of the water vapor barrier resin layer laminated on both sides of the oxygen barrier resin layer is 50 to 300 μm. The styrene resin layer The thickness is 200 to 900 μm. The multilayer resin film according to item 1 of the scope of the patent application, wherein the difference in oxygen transmission rate before and after the multilayer resin film is placed in a high-temperature and high-humidity environment is maintained below 1.0 cc / m ² ‧day. The multilayer resin film according to item 1 or 2 of the scope of the patent application, wherein the multilayer resin film has an oxygen transmission rate of less than 5.0 cc / m ² ‧day and a water vapor transmission rate of 3.0 g / m ² Less than ‧day. The multilayer resin film according to item 1 or 2 of the scope of patent application, wherein the thickness of the oxygen-barrier resin layer is set to 10 to 50 μm. The multilayer resin film according to item 1 or 2 of the scope of patent application, wherein the thickness of each bonding layer is set to 10 to 50 μm. The total thickness of the olefin-based resin layer is 10 μm or more and less than 50 μm. The multilayer resin film according to item 1 or 2 of the scope of the patent application, wherein the styrene-based resin layer is formed of a styrene-based resin containing a butadiene rubber component with a mass percentage of 4 to 8%. The multilayer resin film according to item 1 or 2 of the scope of patent application, wherein the thickness of the multilayer resin film is set to 500 to 1000 μm. A molded container obtained by thermoforming the multilayer resin film according to any one of claims 1 to 7 of the scope of patent application.