JP2000211067A - Multilayered package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered package excellent in gas barrier properties, aroma retaining properties, non-adsorbability of an aromatic component, low temp. sealability and the impact resistance of a heat-sealed part. SOLUTION: A multilayered package has an innermost layer being a layer of resin compsn. prepared by compounding a saponified ethylene/vinyl acetate copolymer with an ethylene content of 20-60 mol% and a saponification value of 98 mol% or less lowered in the saponification value of its vinyl acetate component by a re-acetylation method with other saponified ethylene/vinyl acetate copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer package of saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH), and more particularly to gas barrier properties, fragrance retention properties, and non-adsorption of odor components. The present invention relates to a multilayer package excellent in heat resistance, low-temperature sealability and heat resistance of a heat-sealed portion.

[0002]

2. Description of the Related Art EVOH is excellent in transparency, gas barrier properties, fragrance retention, solvent resistance, oil resistance, and the like.
It is used by being formed into films and sheets of industrial chemical packaging materials, agricultural chemical packaging materials and the like, or containers such as tubes, cups, trays and bottles. In particular, by utilizing properties such as gas barrier properties, non-adsorption of aroma components, organic solvent barrier properties, and solvent crack resistance, it is also useful to use not only the middle layer and the outermost layer but also the innermost layer of a multilayer package. is there. However, EVOH is inferior in low-temperature sealability and mechanical strength (impact resistance) of a heat-sealed portion, so that its practical use has been difficult. In order to remedy such drawbacks, the Applicant has identified two types of E
It has been proposed to use a blend of VOH (Japanese Unexamined Patent Publication No.
JP-A-161447) and JP-A-3-11265.
No. 4 and JP-A-3-112655 disclose that the relationship between two types of EVOH is defined in detail.

[0003]

However, in the technology disclosed in Japanese Patent Application Laid-Open No. 60-161449, although the low-temperature sealing property and the impact resistance of the heat-sealed portion are improved, one of the blended materials is not used. As the ethylene content of EVOH is as large as 70 to 90 mol%, the organic solvent resistance, the fragrance retention, and the non-adsorption of the fragrance component are not sufficient, so that it is used as a package for contents containing an organic solvent or a fragrance component. Is not suitable. In the technology disclosed in JP-A-3-112654 and JP-A-3-112655,
Although gas barrier properties, fragrance retention properties, non-adsorption of fragrance components and improved low-temperature sealing properties are seen, the impact resistance of the heat-sealed part is not sufficient, resulting in vibration during transportation and dropping during storage. It has been found that there is a problem that the package is likely to be damaged from the heat-sealed portion due to a shocking stress or a stress due to the filling of contents during automatic filling and packaging. That is, a multilayer package excellent in all of gas barrier properties, fragrance retention properties, non-adsorption of aroma components, low-temperature sealing properties, and impact resistance of a heat-sealed portion is desired.

[0004]

Accordingly, as a result of intensive studies in view of the above-mentioned circumstances, as a result of reducing the saponification degree of the vinyl acetate component by the re-acetylation method, an ethylene content of 20 to 60 mol%, a saponification degree A multilayer package having a resin composition layer containing 98 mol% or less of EVOH (A) or another EVOH (B) as the innermost layer has a gas barrier property, a fragrance retention property, a non-adsorption property of a fragrance component, and a low temperature. The inventor has found that the sealability and the heat resistance of the heat-sealed portion are all excellent, and the present invention has been completed.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
EVOH (A) used in the present invention is obtained by re-acetylation,
It is necessary that the ethylene-vinyl alcohol copolymer be EVOH with a reduced degree of saponification of the vinyl acetate component,
Such an ethylene-vinyl alcohol copolymer is usually obtained by saponification of an ethylene-vinyl acetate copolymer,
The ethylene-vinyl acetate copolymer is produced by any known polymerization method, for example, suspension polymerization, emulsion polymerization, solution polymerization, or the like, and saponification of the ethylene-vinyl acetate copolymer can be performed by a known method.

The ethylene-vinyl alcohol copolymer may further copolymerize an ethylenically unsaturated monomer copolymerizable within a range not to impair the effects of the present invention. Is propylene, 1-butene,
Unsaturated acids such as olefins such as isobutene, acrylic acid, methacrylic acid, crotonic acid, (anhydrous) phthalic acid, (anhydrous) maleic acid, (anhydrous) itaconic acid or salts thereof, or mono- or dialkyl having 1 to 18 carbon atoms Esters, acrylamide, C-C18 N-alkylacrylamide, N, N-dimethylacrylamide, 2
-Acrylamidopropanesulfonic acid or a salt thereof,
Acrylamides such as acrylamidopropyldimethylamine or an acid salt thereof or a quaternary salt thereof, methacrylamide, N-alkylmethacrylamide having 1 to 18 carbon atoms, N, N-dimethylmethacrylamide, 2-methacrylamidopropanesulfonic acid or the like Salts, methacrylamides such as methacrylamidopropyldimethylamine or an acid salt or a quaternary salt thereof, N-vinylamides such as N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, acrylonitrile,
Vinyl cyanides such as methacrylonitrile, having 1 to 1 carbon atoms
18, vinyl ethers such as alkyl vinyl ether, hydroxyalkyl vinyl ether and alkoxyalkyl vinyl ether; vinyl chlorides such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride and vinyl bromide; vinyl silanes such as trimethoxy vinyl silane; Allyl, allyl chloride, allyl alcohol, dimethylallyl alcohol, trimethyl- (3-acrylamido-3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropanesulfonic acid and the like can be mentioned.

[0007] The ethylene content of the ethylene-vinyl alcohol copolymer is 20 to 60 mol% (more preferably 30 to 5 mol%).
5 mol%, especially 35 to 50 mol%, and the degree of saponification is 98 mol% or more (furthermore, 98.5 mol% or more, particularly 99 mol%).
When the ethylene content is less than 20 mol%, the gas barrier property and the melt moldability at high humidity decrease, and when the ethylene content exceeds 60 mol%, sufficient gas barrier properties cannot be obtained, and the saponification degree is further reduced. If it is less than 98 mol%, the gas barrier properties after re-acetylation will be insufficient, and if the ethylene content or the degree of saponification is out of the above ranges, the compatibility with EVOH (B) will be unstable, and the object of the present invention will be described. Is difficult to achieve. The melt flow index (MI) of the ethylene-vinyl alcohol copolymer is not particularly limited, but may be 0.1 to 100.
g / 10 minutes (210 ° C, 2160g load value; the same applies hereinafter)
It is preferable that the MI is less than 0.1 g / 10 min. If the MI is less than 0.1 g / 10 min, the re-acetylation reaction becomes uneven. It is not preferable because it is difficult to control the melt extrusion during the formation. Further, the ethylene-vinyl alcohol copolymer preferably has a water content of 0.001 to 30% by weight, and if the water content is less than 0.001% by weight, gels and foreign substances frequently occur in the reaction product. And conversely, the water content is 3
If it exceeds 0% by weight, the progress of the re-acetylation reaction may be hindered, which is not preferred.

[0008] EVOH (A) used in the present invention is obtained by re-acetylating the above-mentioned ethylene-vinyl alcohol copolymer, and such a method will be specifically described. The re-acetylation of the ethylene-vinyl alcohol copolymer is not particularly limited.
-106112, JP-A-5-202240, JP-A-6-41369, JP-A-6-2348
No. 99, JP-A-7-3525, water and glacial acetic acid and hydrochloric acid are added to an ethylene-vinyl alcohol copolymer to re-acetylate it in a solution state, or in the presence of an acid. A method of re-acetylation in a molten state may be mentioned, but re-acetylation in a molten state is preferred from the viewpoint of production efficiency. In bringing the ethylene-vinyl alcohol copolymer into a molten state, the solid (powder, pellet, or the like) may be heated and melted at a temperature equal to or higher than the melting point, and the means is not particularly limited. For example, kneader ruder, extruder, mixing roll, Banbury mixer,
It can be carried out using a known kneading device such as a plast mill, but it is usually industrially preferable to use a single-screw or twin-screw extruder, and if necessary, a vent suction device, a gear pump device, a screen It is also preferable to provide a device or the like.
In a molten state (usually at least the temperature of the extruder after C3 is set to be equal to or higher than the melting point of the copolymer). In order to allow the acid to coexist in such a molten state, a method in which the ethylene-vinyl alcohol copolymer is previously blended with the extruder before being supplied to the extruder, the ethylene-vinyl alcohol copolymer and the acid are collectively A method in which the ethylene-vinyl alcohol copolymer is supplied to the extruder and melted to supply an acid, a method in which at least two of the above-mentioned methods are combined, and the like. However, preferably, the following method can be adopted. Such acids include acetic anhydride, acetic acid such as glacial acetic acid, hydrochloric acid, nitric acid, sulfuric acid,
Propionic acid and the like can be mentioned, and acetic anhydride is preferably used in terms of the efficiency and stability of the re-acetylation reaction. Furthermore, other acids or pyridine can be used in combination. Also, the coexisting amount of acetic acid is 1 to 60 mol% (more preferably 2 to 60 mol%) based on all hydroxyl groups in the ethylene-vinyl alcohol copolymer.
If the amount is less than 1 mol%, it becomes difficult to advance a predetermined amount of the re-acetylation reaction. Conversely, if the amount exceeds 60 mol%, the ethylene-vinyl alcohol copolymer is not reacted during the reaction. Thermal degradation may occur, and further treatment of residual acid is required, which is not preferable. Here, the acetic acid mole% (Q) is calculated by the following equation (1).

[0009]

(Equation 1) (Where K is a constant, 0.0196 for acetic anhydride, 0.0167 for glacial acetic acid, X is the amount of acetic acid added to 100 parts by weight of ethylene-vinyl alcohol copolymer (parts by weight), and Y is Ethylene content in the ethylene-vinyl alcohol copolymer (mol%), Z is the degree of saponification of the vinyl acetate component in the ethylene-vinyl alcohol copolymer (mol%)
Respectively. )

Further, the residence time in the extruder is preferably 1 minute to 1 hour (more preferably 3 to 30 minutes).
If it is less than 1 minute, it is difficult to allow the reaction to proceed sufficiently. If it exceeds 1 hour, the ethylene-vinyl alcohol copolymer may be thermally degraded, which is not preferable.

The ethylene-vinyl alcohol copolymer is re-acetylated by the above-mentioned method. In the present invention, the degree of saponification of the vinyl acetate component to be reduced by the re-acetylation is 1 to 30 mol. % (More preferably 1 to 10 mol%), and the degree of saponification is 1
If the amount is less than mol%, the desired EVOH (A) is hardly obtained with little difference in physical properties as compared with the polymer before re-acetylation, and the effect of the present invention may not be obtained. Acetic acid and severe extrusion conditions (high temperature and long time) are required, and the resulting re-acetated product may be deteriorated.
The compatibility with H (B) may be poor, which is not preferable. The degree of saponification can be adjusted by controlling the residence time and temperature in the extruder, the degree of kneading, the type and amount of acid used, and the like. In addition, in order to remove by-products due to re-acetylation, one or more vent holes are provided in the extruder and suction is performed under reduced pressure to obtain a high-quality re-acetylated product. By providing a gear pump between the machine and the die, it is possible to carry out the extrusion reaction more efficiently and stably. The obtained EVOH (A) may further contain a plasticizer, a lubricant, a slip agent, an anti-blocking agent, a heat stabilizer, an ultraviolet absorber, an antioxidant, if necessary.
Additives such as an antistatic agent, a surfactant, a coloring agent, an antibacterial agent, and a filler, and other resins can also be blended. In particular, a hydrotalcite-based compound, a hindered phenol-based, a hindered amine-based heat stabilizer, and a metal salt of a higher aliphatic carboxylic acid can also be added as a gel generation inhibitor.

Further, in the present invention, EVOH (A)
It is also preferable to mix other EVOH (B) having different structures and molecular weights from the viewpoint that a package having further improved gas barrier properties and fragrance retention properties can be obtained. Such EVOH (B) has an ethylene content of 20%. ~ 60 mol%, saponification degree 98
The EVOH is not particularly limited as long as it is at least mol%, and is usually obtained by saponification of an ethylene-vinyl acetate copolymer in the same manner as the above-mentioned ethylene-vinyl alcohol copolymer. The polymer may be prepared by any known polymerization method, for example, suspension polymerization, emulsion polymerization,
It is produced by solution polymerization or the like, and saponification of the ethylene-vinyl acetate copolymer can be performed by a known method. Further, the EVOH (B) may also further copolymerize an ethylenically unsaturated monomer copolymerizable within a range that does not impair the effects of the present invention, similarly to the above ethylene-vinyl alcohol copolymer. Examples of such a monomer include olefins such as propylene, 1-butene, and isobutene, and unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, (phthalic anhydride), maleic anhydride, and itaconic acid. Or a salt thereof or a mono- or dialkyl ester having 1 to 18 carbon atoms, acrylamide, an N-alkylacrylamide having 1 to 18 carbon atoms, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or a salt thereof, acrylamidopropyldimethylamine Or acrylamides such as acid salts or quaternary salts thereof, methacrylic acid Bromide, N- alkyl methacrylamides having 1 to 18 carbon atoms, N, N- dimethyl methacrylamide, 2-
Methacrylamidopropanesulfonic acid or a salt thereof,
Methacrylamides such as methacrylamidopropyldimethylamine or an acid salt or a quaternary salt thereof;
N-vinylamides such as vinylpyrrolidone, N-vinylformamide and N-vinylacetamide; vinyl cyanides such as acrylonitrile and methacrylonitrile; vinyl ethers such as alkyl vinyl ethers having 1 to 18 carbon atoms, hydroxyalkyl vinyl ethers and alkoxyalkyl vinyl ethers , Vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, vinyl halides such as vinyl bromide, vinylsilanes such as trimethoxyvinylsilane, allyl acetate, allyl chloride, allyl alcohol, dimethylallyl alcohol, trimethyl- ( 3-
(Acrylamide-3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropanesulfonic acid and the like.

The EVOH (B) has an ethylene content of 20 to 60 mol% (furthermore, 25 to 50 mol%,
In particular, the degree of saponification needs to be 98 mol% or more (more preferably 98.5 mol% or more, particularly 99 mol% or more). If the ethylene content is less than 20 mol%, the saponification degree becomes high. The gas barrier property at the time of wetness and the melt moldability are reduced, and if it exceeds 60 mol%, sufficient gas barrier property cannot be obtained.
Further, even if the degree of saponification is less than 98 mol%, sufficient gas barrier properties cannot be obtained, and it is difficult to achieve the object of the present invention. The melt flow index (MI) of the EVOH (B) is not particularly limited, but is 0.1 to 100 g.
/ 10 min (210 ° C., 2160 g load value; the same applies hereinafter), and more preferably 0.5 to 50 g / 10 min. If the MI is less than 0.1 g / 10 min, the viscosity becomes too high and the Extrusion can be difficult,
If it exceeds 00 g / 10 minutes, the mechanical strength of the molded product is insufficient, which is not preferable.

The mixing ratio of the EVOH (A) and the EVOH (B) is not particularly limited.
The blending ratio (weight ratio) of (B) is A / B = 2 / 98-50.
/ 50 (further A / B = 5/95 to 45/55, especially A
/ B = 10/90 to 40/60), and when the compounding ratio is smaller than 2/98, the effect of improving the low-temperature sealing property and the mechanical strength (impact resistance) of the heat-sealed portion is poor. On the other hand, if the ratio is larger than 50/50, the compatibility between the two becomes unstable and the moldability decreases, which is not preferable. In addition, as long as the effects of the present invention are not impaired,
As the VOH (A) or the EVOH (B), it is also possible to use two or more types of EVOHs having different structures, molecular weights and the like.

[0015] EVOH (A) re-acetylated as described above,
Further, in order to form a multilayer package using a resin composition containing EVOH (B), the EVOH (A) or EVOH
(B) may be blended so that the layer of the resin composition becomes the innermost layer of the multilayer package, and a known method can be employed. Specifically, EVOH (A) or EVOH (B)
Laminating another base material such as a thermoplastic resin on one or both sides of the layer of the resin composition containing the obtained, to obtain a laminate, it may be a package, to obtain such a laminate, For example, EV
A method in which a thermoplastic resin or the like is melt-extruded into a film or sheet of a resin composition containing OH (A) or EVOH (B), and conversely, EVOH (A) or EVOH (B) is applied to a base material such as a thermoplastic resin. A method of melt-extruding the compounded resin composition, a method of co-extruding a resin composition containing EVOH (A) or EVOH (B) and another thermoplastic resin, and further, a method of EVOH (A) or EVOH (B) ) Is dry-laminated using a known adhesive such as an organotitanium compound, an isocyanate compound, a polyester-based compound, or a polyurethane compound. No. In obtaining the above films and sheets,
Pelletized EVOH (A) or EVOH (B)
May be extruded (T-die extrusion, inflation extrusion, blow molding, profile extrusion, etc.), and the melt molding temperature is often selected from the range of 150 to 300 ° C.

In the case of co-extrusion, the mating resin is a linear low-density polyethylene, ultra-low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene. Copolymers, ethylene-acrylate copolymers, polypropylene, propylene-α-olefin (α-olefins having 4 to 20 carbon atoms) copolymers, homo- or copolymers of olefins such as polybutene, polypentene, and blends Or polyolefin resins in a broad sense such as those obtained by graft-modifying a product or a homo- or copolymer of these olefins, a blend with an unsaturated carboxylic acid or an ester thereof, polyester, polyamide, copolyamide, semi-crystalline polyamide, amorphous Polyamide, polyvinyl chloride, poly Examples include vinylidene chloride, acrylic resin, polystyrene, vinyl ester resin, polyester elastomer, polyurethane elastomer, chlorinated polyethylene, chlorinated polypropylene, aromatic or aliphatic polyketone, and polyalcohol. EVO
H can also be coextruded. Among the above, from the viewpoint of easiness of coextrusion film formation and practicality of film physical properties (particularly strength),
Polypropylene, polyamide, polyethylene, ethylene-vinyl acetate copolymer, polystyrene, PET, PEN
Is preferably used. Further, EVOH (A) or E
A molded product such as a film or a sheet is once obtained from the resin composition containing VOH (B), and another substrate is extrusion-coated thereon, or a film or sheet of another substrate is laminated using an adhesive. In this case, any substrate (paper, metal foil, non-stretched, uniaxially or biaxially stretched plastic film or sheet, woven fabric, nonwoven fabric, metal flocculent, woody, etc.) other than the above-mentioned thermoplastic resin can be used. .

The layer structure of the laminate is as described above,
The layer composition may be such that the layer of the resin composition containing (A) or EVOH (B) is the innermost layer. Such a layer is a, and another substrate such as a thermoplastic resin layer or a paper layer is b. , EV
When the conventional EVOH represented by OH (B) is c, not only the a / b two-layer structure but also a / c, a / b /
c, a / c / b, a / b / b, a / b / c / b, a / b
/ C / b / b, a / b / b / c / b / b, a / b / c /
b / c or the like, and preferably, a / b, a /
A layer configuration of b / b, a / b / c / b, and a / b / c / b / b is adopted.

In these laminates, if necessary, an adhesive resin layer is used between the layers. As the adhesive resin, a known adhesive can be used, for example, unsaturated carboxylic acid or its anhydride. 0.8 denatured with material
A polyolefin resin of 6 to 0.95 g / cm ³ is preferable, and can be obtained by copolymerizing or graft-modifying a resin similar to the above-mentioned polyolefin resin with an unsaturated carboxylic acid or an anhydride thereof. Also includes a blend of an unsaturated carboxylic acid or an anhydride thereof with an unmodified polyolefin resin. Examples of the unsaturated carboxylic acid or its anhydride include maleic acid, maleic anhydride, fumaric acid, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, citraconic acid, hexahydrophthalic anhydride and the like. Is preferably used. At this time, the amount of unsaturated carboxylic acid or anhydride contained in the polyolefin resin is preferably 0.001 to 10% by weight, more preferably 0.01 to 5% by weight. If the content in the modified product is small, the adhesive strength decreases, and if it is too large, a crosslinking reaction occurs, and moldability deteriorates, which is not preferable. It is also possible to mix such an adhesive resin in an adjacent layer.

The laminate as described above can be subjected to a (heating) stretching treatment. The (heating) stretching treatment is performed by chucking a film, a sheet, or a parison-like laminate that is thermally uniformly heated. , Plug, vacuum force, pneumatic force, blow, etc. means an operation of uniformly forming into cups, trays, tubes, bottles, and films, and such stretching may be uniaxial stretching or biaxial stretching. Good and high magnification (1.5-9 horizontal and / or horizontal respectively)
Stretching by about 2 times) is better in physical properties, and a laminate excellent in gas barrier properties, free from pinholes, cracks, stretching unevenness, uneven thickness, and delamination during stretching, can be obtained.

As the stretching method, any of a roll stretching method, a tenter stretching method, a tubular stretching method, a stretch blow method, a vacuum press forming method, and the like having a high stretching ratio can be employed. In the case of biaxial stretching, any of a simultaneous biaxial stretching method and a sequential biaxial stretching method can be adopted. The stretching temperature is 60 to 170 ° C,
Preferably, it is selected from the range of about 80 to 160 ° C. After completion of the stretching, it is also preferable to perform heat setting.
The heat setting can be performed by a well-known means, and heat treatment is performed at 80 to 170 ° C., preferably 100 to 160 ° C. for about 2 to 600 seconds while keeping the stretched film in a tensioned state.
Further, when used for heat shrink packaging of raw meat, processed meat, cheese, etc., the product film is not heat-set after stretching, and the raw meat, processed meat, cheese, etc. are stored in the film, 50-130 ° C, preferably 70-120 ° C
Then, the film is subjected to a heat treatment for about 2 to 300 seconds to thermally shrink the film to perform tight packaging.

In the above laminate, the thickness of each layer is not particularly limited, but the heat seal layer (EVOH (A)
Alternatively, the thickness of the resin composition layer containing the EVOH (B) is 5 μm in order to satisfy the mechanical strength (impact resistance) of the heat-sealed portion of the laminate and the obtained package.
The above (more preferably, 10 μm or more) is preferable. It is also preferable to provide a printing layer between the thermoplastic resin layer and the heat sealing layer. The printing surface can be on either the thermoplastic resin layer side or the heat seal layer side. For printing, a known printing method, apparatus, or ink such as gravure printing, flexographic printing, or screen printing can be used.

Thus, a laminate for use in the multilayer package of the present invention can be obtained.
It is also preferable that the layer of the resin composition containing H (A) or EVOH (B) is the innermost layer, and the layers are further heat-sealed to form a multilayer package. For example, EVs such as cups, trays and bottles obtained from the laminate of the present invention
A layer of a resin composition containing OH (A) or EVOH (B) and a film (lid material) obtained from the laminate of the present invention
EVOH (A) or EVOH of a film formed by heat-sealing the same layer with
A packaging bag formed by heat-sealing layers of the resin composition containing (B) or a layer of the resin composition containing EVOH (A) or EVOH (B) of a tube obtained from the laminate of the present invention. Tubular containers formed by heat-sealing each other are exemplified. Further, a goebel top type paper container or a cylindrical type paper container using the resin composition layer of the present invention as the innermost layer of a paper container may also be used.

As the heat sealing device, a normal device such as a hot plate type or an impulse type can be employed, but a hot plate type is preferable from the viewpoint of accuracy of temperature control and shortening of the heat sealing time. Heat sealing time (contact time of hot plate) is 0.1 ~
It is about 5 seconds. When a packaging bag is obtained, a normal bag making machine can be employed. For example, a hot bar seal type or hot roll type bag making machine can be used,
It is processed into bags of one-sided seal type, three-sided seal type, double-sided seal type and the like. In addition, an automatic bag making and filling machine such as a pillow package, a three-side seal package, and a four-side seal package that simultaneously perform bag making and filling can also be used.

The multilayer package of the present invention can be used for gas barrier packaging of foods and beverages, especially foods and beverages and flavors containing fragrance components, pharmaceuticals and cosmetics, moisture-proof packaging, heat sterilization packaging, high-temperature packaging, automatic packaging, and high-speed packaging. Useful in various packaging applications such as packaging, pillow packaging, microwave packaging, stretch packaging, shrink packaging, PTP (press-through pack) packaging, and bag-in-box. In addition, industrial chemicals, agricultural chemicals, electronic components, and mechanical components It is also useful as various packaging materials.

[0025]

The present invention will be specifically described below with reference to examples. In the Examples, “parts” and “%” are based on weight unless otherwise specified. Example 1 [Production of EVOH (A)] Ethylene-vinyl alcohol copolymer [ethylene content 47 mol%, saponification degree 99.
2 mol%, melting point: 158 ° C., MI: 30 g / 10 min, water content: 0.3%] 100 parts of acetic anhydride (10.9 mol% based on all hydroxyl groups in EVOH) is added. After mixing, it is fed to a twin-screw extruder (co-directional twin-screw extruder),
The re-acetylation treatment was performed in a molten state (melting temperature 270 ° C.) under the following conditions. (Melt extrusion conditions of the extruder) Screw inner diameter 30 mm L / D 49 Extrusion temperature C1: 180 ° C A: 250 ° C C2: 220 ° C D: 250 ° C C3: 270 ° C C4: 270 ° C C5: 270 ° C C6: 270 ° C C7 : 270 ° C C8: 270 ° C Average residence time 10 minutes

The extruder is extruded in a molten state from a die at the tip of the extruder into a strand, then cooled and solidified by passing through cooling water (5 ° C.), cut with a pelletizer, and treated with EVOH (A) [ethylene A pellet having a content of 47 mol% and a saponification degree of 94.9 mol%] was obtained. 20 parts of the EVOH (A) obtained above and EVO
H (B) [ethylene content 35 mol%, saponification degree 99.
6 mol%, MI is 3 g / 10 min] 80 parts of diameter 40 mm
And melt-mixed at a temperature of 230 ° C. to obtain a resin composition. The obtained resin composition was supplied to a single-layer T-die extruder to obtain a film having a thickness of 20 μm. Next, a commercially available biaxially stretched nylon film (thickness: 15 μm)
After applying a polyurethane-based adhesive to the mixture and evaporating the solvent, the EVOH blend film obtained above was dry-laminated to produce a laminate. The oxygen permeability of the obtained laminate was measured using "OXTRA" manufactured by Modern Control.
N10 / 50 "and found to be 0.59 cc / m ²
・ Atm.day (23 ° C., 50% RH) showed very good gas barrier properties.

Further, the obtained laminated body was 20 cm in length × 1 in width.
After cutting to 5 cm (two pieces), the layers of the resin composition are overlapped so that they are on the inside, and three sides are heat-sealed (sealed) with a hot plate heat sealer at a temperature of 155 ° C. and a pressure of 2 kg / cm ² for 2 seconds. (Width 5 mm) to prepare a packaging bag. After leaving the packaging bag in a constant temperature room at 23 ° C. for one day,
When the seal portion was cut out into a strip shape with a width of 15 mm and the seal portion was peeled off at 50 mm / min with a tensile tester,
The seal strength was 1.7 kg / 15 mm, indicating good low-temperature sealability. Further, 300 cc of water to which a few drops of orange essence were added was put into the packaging bag, and the opening was similarly heat-sealed and sealed. Then, it was sealed in a 2-liter glass container and stored at 23 ° C. Even after one month, the scent of orange essence was not detected in the glass container, and when the scent was confirmed by opening the packaging bag,
No change in fragrance was observed, showing good fragrance retention and non-adsorption of fragrance components. Similarly, the packaging bag sealed with 300 cc of water is freely dropped five times at 23 ° C. from a height of 1 m on the concrete surface so that the heat sealing portion directly hits the concrete surface (10 samples). When the impact resistance was examined, no water leakage from the portion was observed.

Example 2 In Example 1, EVOH prepared as follows
A resin composition was obtained in the same manner except that 30 parts of (A) and 70 parts of EVOH (B) were used, and a laminate was obtained in the same manner, and evaluation was similarly performed. As a result, the oxygen permeability of the laminate was 0.6
6cc / m ² · atm · day (23 ° C, 50% RH)
And showed very good gas barrier properties, and the sealing strength of the heat seal portion (155 ° C.) of the packaging bag was 1.6 kg / 15.
mm, it shows good low-temperature sealing properties, and the fragrance of orange essence is not detected in the glass container even after one month, even for the fragrance retention and non-adsorption of fragrance components of the packaging bag,
Further, when the packaging bag was opened and the scent was confirmed, no change in the scent was observed, showing good scent retention and non-adsorption of scent components, and furthermore, the heat-sealed part of the water-sealed packaging bag. Regarding impact resistance, no water leakage was observed in any of the ten samples.

[Production of EVOH (A)] Ethylene-vinyl alcohol copolymer [ethylene content: 44 mol%, saponification degree: 99.6 mol%, melting point: 164 ° C., MI: 12 g /
10 minutes, water content 0.2%] and 100 parts of acetic anhydride (E
After adding 7.8 mol% to the total hydroxyl groups in VOH and mixing well, a twin-screw extruder (co-directional twin-screw extruder)
And melted under the following conditions (melting temperature 280)
° C). (Melting extrusion conditions of the extruder) Screw inner diameter 30 mm L / D 42 Extrusion temperature C1: 200 ° C A: 260 ° C C2: 240 ° C D: 260 ° C C3: 270 ° C C4: 280 ° C C5: 280 ° C C6: 280 ° C C7 : 280 ° C. Average residence time 5 minutes Extruded in a molten state from a die at the tip of the extruder in a molten state, then cooled and solidified by passing through cooling water (5 ° C.), cut with a pelletizer, and cut with an EVOH. (A) [ethylene content 44 mol%,
A pellet having a saponification degree of 96.1 mol%] was obtained.

Example 3 In Example 2, the EVOH (B) was an ethylene content of 32 mol%, a saponification degree of 99.6 mol%, and an MI of 6 g.
EVOH (A) and EVOH
A resin composition was obtained in the same manner except that the mixing ratio of (B) was 25 parts (A) and 75 parts (B), and a laminate was obtained in the same manner.
Evaluation was performed similarly. As a result, the oxygen permeability of the laminate was 0.59 cc / m ² .atm.day (23 ° C., 5
0% RH), it shows very good gas barrier properties, and the sealing strength of the heat seal portion (155 ° C.) of the packaging bag is 1.6.
kg / 15 mm, it shows good low-temperature sealing properties, and the fragrance of orange essence is not perceived in the glass container even after one month with respect to the fragrance preservation property and the non-adsorption property of the fragrance component of the packaging bag. When the packaging bag was opened and the fragrance was confirmed, no change in fragrance was observed, showing good fragrance retention and non-adsorption of aroma components, and the impact resistance of the heat-sealed portion of the water-sealed packaging bag. No water leakage was observed for any of the ten samples.

Example 4 In Example 1, the obtained resin composition was supplied to a multilayer extruder equipped with a three-type and three-layer inflation die.
[Outer layer] Same as above except that a three-layered three-layered product (thickness: 50/20/30 (μm)) of a polypropylene layer / adhesive resin (maleic anhydride-modified polypropylene) layer / resin composition layer [inner layer] was prepared. To obtain a laminate, and similarly evaluated. However, since the laminate was formed using an inflation die, heat sealing was performed only on the upper and lower sides. As a result, the oxygen permeability of the laminate was 0.44 cc / m ² ···
Atm.day (23 ° C., 50% RH) shows very good gas barrier properties, and the heat seal portion (15
(5 ° C.) The seal strength is 1.9 kg / 15 mm, showing good low-temperature sealability. The fragrance preserving property of the packaging bag and the non-adsorbing property of the fragrance component are shown in the glass container even after one month. No scent was perceived, and when the packaging bag was opened and the scent was confirmed, no change in scent was observed, showing good scent retention and non-adsorption of scent components. Regarding the impact resistance of the heat-sealed portion of the bag, no water leakage was observed in any of the ten bags.

Example 5 A laminate was obtained in the same manner as in Example 2 except that EVOH (B) was not mixed, and the evaluation was performed in the same manner. As a result, the oxygen permeability of the laminate was 5.0 cc / m ² · a.
tm-day (23 ° C, 50% RH) shows good gas barrier properties, and the sealing strength of the heat seal part (140 ° C) of the packaging bag is 1.7kg / 15mm, showing very good low-temperature sealability. The fragrance of orange essence was not detected in the glass container even after one month with respect to the fragrance retention property and the non-adsorption property of the fragrance component of the packaging bag, and the fragrance was confirmed by opening the packaging bag. No change in scent was observed, showing good scent retention and non-adsorption of scent components. Furthermore, no water leak was observed in the heat resistance of the heat-sealed part of the water-sealed packaging bag. Was.

Comparative Example 1 In Example 1, a normal EVOH obtained by saponifying an ethylene-vinyl acetate copolymer with an alkali catalyst in place of EVOH (A) [ethylene content: 47 mol%, saponification degree: 9
5.0 mol%], an EVOH composition was obtained in the same manner, a laminate was obtained in the same manner, and evaluation was performed in the same manner. As a result, the oxygen permeability of the laminate was 0.69 cc / m ² · a.
tm.day (23 ° C., 50% RH), showing very good gas barrier properties, and a heat-sealed portion (155
° C) seal strength is 1.4 kg / 15 mm, and the fragrance of orange essence is not perceived in the glass container even after one month with respect to the fragrance preserving property and the non-adsorbing property of the fragrance component of the packaging bag. When the package was opened and the scent was confirmed, no change in the scent was observed. However, the impact resistance of the heat-sealed portion of the water-sealed packaging bag was similarly evaluated. As a result, two out of ten water leaks were observed, and there was no further water leak.
Three of the 0 pieces were recognized, and the heat resistance of the heat-sealed portion was poor.

[0034]

The multilayer package of the present invention uses a layer containing EVOH obtained by a specific method as the innermost layer, so that it has a gas barrier property, a fragrance retention property, a non-adsorption property of a fragrance component, and a low-temperature sealing. Food, beverages, especially foods and beverages and fragrances containing fragrance components,
Pharmaceutical and cosmetic gas barrier packaging, moisture-proof packaging, heat sterilization packaging, high-temperature packaging, automatic packaging, high-speed packaging, pillow packaging, microwave packaging, stretch packaging, shrink packaging, PTP (press-through pack) packaging, bag-in-box It is also useful as various packaging materials, such as industrial chemicals, agricultural chemicals, electronic parts, and mechanical parts.

[Procedure amendment]

[Submission date] March 1, 2000 (200.3.1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 4

[Correction method] Change

[Correction contents]

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F100 AK48 AK51G AK69A AL05A AL06A AT00B BA02 CB02 EC03 GB01 GB23 GB66 JD01 JD02 JK10 JL12 YY00A

Claims (5)

[Claims] 1. A saponified ethylene-vinyl acetate copolymer (A) having an ethylene content of 20 to 60 mol% and a saponification degree of 98 mol% or less, wherein the saponification degree of the vinyl acetate component is reduced by a re-acetylation method. Characterized in that a resin composition layer containing the above is used as an innermost layer. 2. A saponified ethylene-vinyl acetate copolymer (A) having an ethylene content of 20 to 60 mol% and a saponification degree of 98 mol% or less, wherein the saponification degree of the vinyl acetate component is reduced by a re-acetylation method. And a resin composition layer containing a saponified ethylene-vinyl acetate copolymer (B) having an ethylene content of 20 to 60 mol% and a degree of saponification of 98 mol% or more, which is the innermost layer. . 3. Saponified ethylene-vinyl acetate copolymer (A) and saponified ethylene-vinyl acetate copolymer (B)
A / B = 2/98 to 50/50
The multilayer package according to claim 2, wherein: 4. A saponified ethylene-vinyl acetate copolymer is re-acetylated in the presence of acetic acid in a molten state of an ethylene-vinyl alcohol copolymer to reduce the saponification degree of the vinyl acetate component to 1 to 30 mol%. The multilayer package according to any one of claims 1 to 3, wherein the package is obtained by lowering the multilayer package. 5. The multilayer package according to claim 1, wherein the innermost resin composition layers are heat-sealed.