JP3091275B2 - Heat shrinkable film and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-shrinkable multilayer film having excellent gas barrier properties and easy to produce.

[0002]

BACKGROUND OF THE INVENTION Many fatty foods such as raw meat and processed meat have irregular shapes and irregular sizes. As described above, shrink wrapping using a heat-shrinkable film has been industrially adopted as a method of packing food having various forms.
The general operating procedure of this method is to put the contents in a bag-like film, then remove the air in the bag under reduced pressure, seal the opening of the bag, and heat-treat the film by heat treatment. At the very least, it is necessary to obtain a beautiful package by closely adhering to the contents. In this method, the heat treatment may be performed also for sterilization of the contents, and is usually 70 to
A temperature of 120 ° C. is employed.

[0003] The film used for such shrink wrapping has excellent gas barrier properties and adhesiveness, and is 70 to 1%.
It is necessary to have a property of sufficiently contracting by heating with hot water of 20 ° C. or hot air.

[0004] Ethylene-vinyl alcohol copolymer (hereinafter referred to as EVOH) has high gas barrier properties. Although it is conceivable to prepare a film for shrink wrapping using these EVOH resins, it is not possible to obtain a film for shrink wrapping which is inferior in stretchability to an EVOH resin film.

Various proposals have been made to solve this disadvantage. For example, JP-A-56-136365 discloses a polyolefin layer, a polyamide resin layer and an EVOH layer.
A laminated film composed of a resin layer and the like are described.

However, even if the EVOH resin alone is laminated with the polyamide resin, satisfactory stretchability cannot be obtained, and a film having uniform heat shrinkability cannot be obtained.

[0007] JP-A-64-9238 discloses EVO.
H: 6-66, 6-12 Nylon melting point 12
It is described that a polyamide resin at 0 to 210 ° C. is blended to improve the stretchability, but nothing is described about using an aromatic polyamide resin. It does not have the excellent gas barrier properties and heat shrinkability of the heat shrinkable multilayer film .

Japanese Patent Application Laid-Open No. 53-49050 discloses a film using a resin obtained by blending a polyamide resin with EVOH. The film is intended to have a boil resistance and a dimensional stability upon heating. Is a gas-barrier film that has been subjected to biaxial stretching and subsequent heat setting, and there is no description of a heat-shrinkable film.

Therefore, it is desired to provide a heat-shrinkable film which has high gas barrier properties, exhibits excellent heat shrinkability and dimensional stability, and is easy to manufacture.

The present inventors have studied to improve the stretchability, heat shrinkage, and dimensional stability of the EVOH resin while maintaining high gas barrier properties. As a result, the stretchability and the heat shrinkability of the EVOH resin itself have been improved. When EVOH resin is blended with an aromatic polyamide resin at a specific ratio, not only the transparency and heat stability are greatly improved, but also the stretchability is extremely improved, and uniform heat shrinkage and dimensional stability are achieved. It has been found that a multilayer film having excellent properties can be obtained, and the present invention has been accomplished.

[0011]

SUMMARY OF THE INVENTION The first object of the present invention is to have excellent adhesion to the contents during heat-shrinking operation, have uniform heat-shrinkability and good dimensional stability, and have gas barrier properties and fragrance retention. An object of the present invention is to provide a heat-shrinkable multilayer film having good heat resistance and organic solvent resistance.

A second object of the present invention is to produce a film having good transparency, which can be produced without forcible stretching orientation, does not generate gels and bumps at the time of production.
It is to provide a heat-shrinkable multilayer film .

[0013]

The above object of the present invention is as follows.
The heat-shrinkable multilayer film and the heat-shrinkable multilayer film
This is achieved by a manufacturing method. (1) Ethylene content of 20 to 60 mol%, saponification degree of 90
% Or more of ethylene - vinyl alcohol copolymer 10-9
5% by weight and aromatic polyamide resin 5-90% by weight
Ethylene-vinyl alcohol copolymer composition layer comprising
(A), copolymerization of ethylene and vinyl ester monomer
Body, aliphatic unsaturated carboxylic acid, aliphatic unsaturated carboxylic acid
A copolymer of ethylene and a monomer selected from esters,
Ionomer resin, linear low density polyethylene, linear low density
Of polyethylene and ethylene-vinyl acetate copolymer
Compound resin, density 0.91 or less, Vicat softening point 95 ° C or less
Ultra low density polyethylene, Vicat with a density of 0.91 or less
Ultra low density polyethylene with a softening point of 95 ° C or less and a small amount of linear
Mixed resin with low density polyethylene and crystalline pro
Pyrene-ethylene copolymer and polypropylene elastomer
At least one selected from the group consisting of mixed resins with
At least one layer (B) made of different kinds of resin
Layer (B) as the innermost layer and in hot water at 90 ° C.
Heat collection with area shrinkage of 10% or more when immersed for 1 minute
Shrinkable multilayer film. (2) At least one polyamide resin layer (C)
And disposing the layer (C) outside the layer (A).
The heat-shrinkable multilayer film according to the above (1), which is characterized in that: (3) The polyamide resin of the polyamide resin layer (C) is aromatic
Heat shrinkability as described in (2) above, which is an aromatic polyamide resin
Multilayer film. (4) Ethylene content 20-60 mol%, saponification degree 90
% Or more of ethylene-vinyl alcohol copolymer 10-9
5% by weight and aromatic polyamide resin 5-90% by weight
Ethylene-vinyl alcohol copolymer composition layer comprising
(A), copolymerization of ethylene and vinyl ester monomer
Body, aliphatic unsaturated carboxylic acid, aliphatic unsaturated carboxylic acid
A copolymer of ethylene and a monomer selected from esters,
Ionomer resin, linear low density polyethylene, linear low density
Of polyethylene and ethylene-vinyl acetate copolymer
Compound resin, density 0.91 or less, Vicat softening point 95 ° C or less
Ultra low density polyethylene, Vicat with a density of 0.91 or less
Ultra low density polyethylene with a softening point of 95 ° C or less and a small amount of linear
Mixed resin with low density polyethylene and crystalline pro
Pyrene-ethylene copolymer and polypropylene elastomer
At least one selected from the group consisting of mixed resins with
At least one layer (B) made of different kinds of resin
The laminate having a heating temperature of 50-140 ° C.,
Or transverse thereto respectively in the said stretching 1.3-9 times
Method for producing the heat-shrinkable multilayer film according to the above (1)
Law. (5) Ethylene content 20-60 mol%, saponification degree 90
% Or more of ethylene-vinyl alcohol copolymer 10-9
5% by weight and aromatic polyamide resin 5-90% by weight
Ethylene-vinyl alcohol copolymer composition layer comprising
(A), polyamide resin layer (C), ethylene and vinyl
Copolymer with ester monomer, aliphatic unsaturated carboxylic acid
Monomers selected from acids and aliphatic unsaturated carboxylic esters
Copolymer of ethylene and ethylene, ionomer resin, linear low
High density polyethylene, linear low density polyethylene and ethylene
-Resin mixed with vinyl acetate copolymer, density 0.91 or less
Ultra low density polyethylene having a Vicat softening point of 95 ° C or less,
Ultra low density with density of 0.91 or less and Vicat softening point of 95 ° C or less
Of low-density polyethylene with a small amount of linear low-density polyethylene
Synthetic resin and crystalline propylene-ethylene copolymer
Consisting of a mixed resin of polypropylene and elastomer
A layer made of at least one resin selected from the group
Heating the laminate having at least one layer each of (B)
At 50-140 ° C, vertically and / or horizontally respectively
The above (2) or (3), characterized in that the film is stretched 1.3 to 9 times.
Is a method for producing a heat-shrinkable multilayer film according to (3).

Hereinafter, the present invention will be described in detail.

In the present invention, the air used for the layer (A) is
Tylene content 20-60 mol%, saponification degree 90% or more
Ethylene-vinyl alcohol copolymer (hereinafter referred to as the present invention)
Recorded as EVOH. ) Is a saponified ethylene-vinyl ester copolymer having an ethylene content of 20-60 mol%, preferably 25-58 mol%, and a saponification degree of the vinyl ester component of 90% or more, preferably 95% or more. Things can be used. If the ethylene content is less than 20 mol%, the melt moldability is poor, while if it is more than 60 mol%, the gas barrier properties are insufficient. If the degree of saponification is less than 90%, the gas barrier properties and the thermal stability deteriorate. A typical example of the vinyl ester is vinyl acetate, but other fatty acid vinyl esters (for example, pivalic acid ester) can also be used.

In the EVOH of the present invention, other comonomers [eg, propylene,
Butylene, unsaturated carboxylic acid or its ester {(meth) acrylic acid, (meth) acrylic acid ester (methyl ester, ethyl ester, etc.), etc.}, vinylsilane compound (vinyltrimethoxysilane, vinyltriethoxysilane, etc.), vinylpyrrolidone (N-vinylpyrrolidone, etc.) can also be copolymerized, and plasticizers, heat stabilizers, ultraviolet absorbers, antioxidants, coloring agents, fillers, and other resins (polyamide, partially saponified ethylene-vinyl acetate copolymer) can be used. Polymers) can also be blended. Also, the melt index (MI) of the EVOH of the present invention.
(At 190 ° C. under a load of 2160 g) is 0.1-50 g / 1.
0 min., Preferably 0.5-20 g / 10 mi.
n.

The aromatic polyamide resin used for the layer (A) is a polycondensate in which one or both of a diamine component and a dicarboxylic acid component are aromatic compounds, and a preferable representative example thereof is a metaxylylene group. Containing polyamide resin.

Examples of the metaxylylene group-containing polyamide resin include metaxylylenediamine and mixed xylylenediamine containing 80% or less of the total amount of paraxylylenediamine, and α, ω-aliphatic dicarboxylic acid having 6 to 10 carbon atoms. A polymer containing at least 70 mol% of a structural unit generated from the above in a molecular chain is preferable. Examples of these polymers include homopolymers such as polymetaxylylene adipamide, polymetaxylylene sebacamide, polymetaxylylene speramide, and the like, and metaxylylene / paraxylylene adipamide copolymers, Copolymers such as meta-xylylene / para-xylylene azeramide copolymers, and the components of these homopolymers or copolymers and aliphatic diamines such as hexamethylene diamine; alicyclic diamines such as piperazine; Aromatic diamines such as para-bis- (2-aminoethyl) benzene, aromatic dicarboxylic acids such as terephthalic acid, lactams such as ε-caprolactam, aminocarboxylic acids such as aminoheptanoic acid, para-aminomethyl Copolymers and the like copolymerized with an aromatic aminocarboxylic acid such as benzoic acid and the like It is. In the above copolymer, the content of paraxylylenediamine is more preferably 75% or less based on the total xylylenediamine. Further, it preferably has at least 70 mol% or more of a structural unit formed from xylylenediamine and an aliphatic dicarboxylic acid in a molecular chain,
More preferably, the content is 75 mol% or more. These polymers include, for example, polymers such as nylon 6, nylon 6-6, nylon 6-10, nylon 11, nylon 12, nylon 6-12, antistatic agents, lubricants, antiblocking agents, stabilizers, and dyes. , A pigment and the like. Relative viscosity of the meta-xylylene group-containing polyamide resin (96%
Sulfuric acid solution (1g / 100ml, 25 ° C) is 1.0-5dl
/ G, more preferably 1.5 to 4 dl / g.

Further, as the aromatic polyamide which can be used in the present invention, an amorphous polyamide can be mentioned. Here, the amorphous polyamide is a polycondensate in which at least one of the diamine component and the dicarboxylic acid component is an aromatic compound, which has substantially no endothermic crystal melting peak in the DSC measurement. A representative example is a polycondensate of an aliphatic diamine and an aromatic dicarboxylic acid.

Examples of the aliphatic diamine include hexamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 2-methylpentamethylenediamine and bis- (4-amino Hexyl) -methane, 2,2-bis-
(4-aminohexyl) -isopropylidene, 1,4-
Examples include diaminocyclohexane, 1,3-diaminocyclohexane, 1,5-diaminopentane, 1,4-diaminobutane, 1,3-diaminopropane, and 2-ethyldiaminobutane. These diamines
One or more can be used simultaneously. Among them, hexamethylenediamine, 2-methylpentamethylenediamine, 1,5-diaminopentane, 1,4-diaminobutane and 1,3-diaminopropane are preferably used.

Examples of the aromatic carboxylic acid include isophthalic acid, terephthalic acid, alkyl-substituted isophthalic acid, alkyl-substituted terephthalic acid, naphthalenedicarboxylic acid, and diphenyl ether dicarboxylic acid. One or more of these dicarboxylic acids can be used simultaneously. Among them, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, diphenyl ether dicarboxylic acid, and the like are preferred in terms of thermoformability, transparency, gas barrier properties, and the like.

Specific examples of the amorphous polyamide include polycondensates of hexamethylenediamine and isophthalic acid, polycondensates of hexamethylenediamine and isophthalic acid / terephthalic acid, 2,2,4-trimethylhexamethylenediamine and 2 , 4,4-trimethylhexamethylenediamine and terephthalic acid.
Among them, the molar ratio of isophthalic acid / terephthalic acid is 6
0 / 40-95 / 5, furthermore 65 / 35-90 / 10
The polycondensate of hexamethylenediamine and isophthalic acid / terephthalic acid in the range of (1) is preferred.

The amount of the aromatic polyamide resin to be added to the EVOH of the present invention is 5-90% by weight, preferably 7-80% by weight. If the addition amount is 5% by weight or less, the effect of improving stretchability is not sufficient, and unevenness is likely to occur. On the other hand, if the content is 90% by weight or more, the gas barrier property is greatly reduced, and it cannot be used as a high gas barrier film.

The method of blending the EVOH of the present invention with an aromatic polyamide resin is not particularly limited. The EVOH of the present invention and the aromatic polyamide resin may be dry-blended and used as they are, but a method of pelletizing and drying using a Banbury mixer, a single-screw or twin-screw extruder, and the like is more preferable. If the blend is non-uniform, or if gels or bumps are generated or mixed during the blend pelletizing operation, there is a high possibility that the EVOH composition layer will be broken, cracked, or uneven during the heat-stretch molding. Therefore, it is desirable to use an extruder with a high degree of kneading during the blend pelletizing operation, seal the hopper port with nitrogen gas, and extrude at a low temperature. Also,
When blending into pellets , other additives (plasticizer, heat stabilizer, ultraviolet absorber, antioxidant, colorant, filler,
Other resins) can be used as long as the object of the present invention is not hindered. In particular, as a measure to prevent gel formation,
0.01-1% by weight of hydrotalcite-based compound, hindered phenol-based, hindered amine-based heat stabilizer
It is preferred to add.

Layer (B) of the heat-shrinkable multilayer film of the present invention
Is a copolymer of ethylene and vinyl ester monomer,
Aliphatic unsaturated carboxylic acid, aliphatic unsaturated carboxylic acid ester
Copolymer of ethylene and a monomer selected from
Nomer resin, linear low-density polyethylene (hereinafter LLDP)
Abbreviated as E. ), LLDPE and ethylene-vinyl acetate
Resin mixed with copolymer (hereinafter referred to as EVA), density
Ultra-low density poise with 0.91 or less and Vicat softening point of 95 ° C or less
Ethylene (hereinafter abbreviated as VLDPE), VLD
Mixed resin of PE and a small amount of LLDPE, and crystallinity
Propylene-ethylene copolymer and polypropylene-based elastomer
At least selected from the group consisting of resin mixed with stoma
Is also composed of one type of resin.

The above ethylene and vinyl ester monomer
Examples of the copolymer include EVA and aliphatic unsaturated carboxy.
Acid or an unsaturated unsaturated carboxylic acid ester
As a copolymer of a monomer and ethylene, for example, acrylic
Acid, acrylate, methacrylic acid, methacrylic acid
Copolymer of ethylene and monomer selected from esters, etc.
Is mentioned. Vicat softening point of 95 at density of 0.91 or less
℃ or lower ultra-low density polyethylene (hereinafter abbreviated as VLDPE
Name. )), The vicat softening point is 85 ° C or less.
Preferably. The above Vicato softening point is ASTM D
It was measured according to -1525. With the above EVA
Preferably have a vinyl acetate content of 3 to 19% by weight.
No. The ratio of EVA in the mixed resin of LLDPE and EVA is
The content of at least 55% by weight indicates that stretchability is high.
Preferred from the ground. As LLDPE, ethylene and small amount
Butene-1, pentene-1, 4-methyl-pentene-
1, hexene-1, octene-1 and the like having 4 to 18 carbon atoms
Copolymer with α-olefin, crystalline melting point 118-125
° C is preferred. As ionomer resin,
Α-olefins such as
With unsaturated carboxylic acids such as tacrylic acid and maleic acid
Polymers and these α- olefin and unsaturated carboxylic San'e
Of a copolymer obtained by partially saponifying a copolymer with stell
Metal ions such as Na, K, Mg, Ca, Zn etc.
A partially neutralized one is used. Usually, Na and
Zn is used. Do not partially neutralize with divalent metal ions
Ionomer resin contains polyamide oligomer
May be available.

One kind of resin constituting the layer (B) is simply
They may be used alone or as a mixture of two or more. Also,
Resins other than the above as long as the effects of the present invention are not impaired
May be used in combination.

In the heat-shrinkable multilayer film of the present invention,
When laminating two or more layers (B),
The resin may be the same or different.
No. The heat-shrinkable multilayer of the present invention having a layer (A) and a layer (B)
In the film, at least one layer (B) is the innermost layer
It is provided as. Example of providing as innermost layer
One surface layer of the heat shrinkable multilayer film as shown in
Means that the heat-shrinkable multilayer film of the present invention is provided.
When using LUM as a packaging material,
Will be in contact with you. Extrusion by laminating layer (B)
Improved moldability, dimensional stability, etc., and excellent sealing properties
Can be given.

Layer (C) of the heat-shrinkable multilayer film of the present invention
As the resin of the polyamide resin layer , nylon 6, nylon 9, nylon 11, nylon 12, nylon 66, nylon 69, nylon 611, nylon 61
2, a copolymer of two or more monomer components, and nylon 6, nylon 9, nylon 11, and nylon 1.
2. Nylon 66, Nylon 69, Nylon 611, Nylon 612, and the aromatic polyamide resin having a better gas barrier property than the polyamide resin, or a copolymer or melt blend of the aromatic polyamide resin and the polyamide resin. A thing is also mentioned as a preferable thing.

The heat-shrinkable multilayer film of the present invention comprises the layer (A)
And layer (B), or layer (A), layer (B) and
It has a layer (C). Layer (A), layer (B) and layer
(C) may each have two or more layers. Layer (A), layer
When each of (B) and the layer (C) has two or more layers,
Even if the resin composition constituting each layer is the same,
They may also be different.

Layers in the Heat Shrinkable Multilayer Film of the Invention
The thickness of (C) is preferably 3 μm or more from the viewpoint of heat resistance and 30 μm or less from the viewpoint of stretchability and dimensional stability.

The thickness of the layer (A) is 3 to 20 μm, preferably 3 to 1, in consideration of the balance between gas barrier properties and stretchability.
5 μm. Further, the thickness of the layer (C) is preferably larger than the thickness of the layer (A). Further, the layer (A) and the layer
When each (C) has two or more layers , the total thickness of the layer (C) is preferably larger than the total thickness of the layer (A), and the total thickness is preferably 15 to 200 μm.

In the layer (A), the layer (B) and the layer (C) , inorganic and / or organic additives such as thermoplastic resins, inorganic fillers and pigments, as long as the stretchability and gas barrier properties are not impaired. Also, it is possible to add a recycled product such as trim and waste generated during film production. The resin containing the recovered and reused product can be separately provided as one or more layers in the laminated film of the present invention.

The method for producing the heat-shrinkable multilayer film of the present invention will be described below.

The heat-shrinkable multilayer film of the present invention can be obtained by lamination by extrusion lamination, dry lamination, coextrusion lamination, coextrusion sheet molding, coextrusion inflation molding, solution coating, or the like. it can. When laminating, an adhesive resin may be interposed between layers.

The adhesive resin is not particularly limited as long as it can firmly bond the respective layers, but may be an unsaturated carboxylic acid or its anhydride (such as maleic anhydride).
With an olefin polymer or copolymer [polyethylene {low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene}, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylate (methyl ester, ethyl And the like) are preferably used.

It is preferred that the extruded laminate be immediately quenched and made as amorphous as practically possible. Next, the laminate is reheated within the range of the melting point of EVOH or less, and is uniaxially or biaxially stretched by a roll stretching method, a pantograph stretching method, an inflation stretching method, or the like. Prior to the stretching, the multilayer structure is irradiated with radiation, electron beam, ultraviolet ray, etc. to crosslink the layers (A), (B), and (C). It is more preferable to use a multilayer structure in which the layer (A) and the layer (C) are laminated on the crosslinked layer (B) because the stretch formability is further improved. The stretching ratio is 1.3 to 9 times, preferably 1.5 to 4 times, respectively in the longitudinal and / or transverse directions, and the heating temperature is 50 to 140 ° C, preferably 60 to 100 ° C. If the heating temperature is lower than 50 ° C. or lower, the stretchability becomes poor and the dimensional change becomes large. Also,
When the heating temperature is 140 ° C. or higher, a desired heat shrinkage cannot be obtained. The area shrinkage when the heat-shrinkable multilayer film of the present invention is immersed in hot water at 90 ° C. for 1 minute is 10% or more, preferably 20% or more, further 30% or more, and more preferably 45% or more. . If the area shrinkage is less than 10%, wrinkles of the film may occur on the surface of the packaged product, or the adhesion between the contents and the packaging film may be impaired, resulting in a poor appearance of the product. The shrinkage in the vertical and / or horizontal direction is preferably 10% or more, and more preferably 15% or more.

The structure of the multilayer film includes a layer (A) /
Adhesive resin layer / layer (B) , layer (B) / adhesive resin layer / layer (A) / adhesive resin layer / layer (B) , layer (A) / layer (C)
/ Adhesive resin layer / layer (B) , layer (B) / adhesive resin layer /
Layer (A) / layer (C) / adhesive resin layer / layer (B) , layer
(C) / layer (A) / adhesive resin layer / layer (B) , layer (B)
/ Adhesive resin layer / layer (A) / adhesive resin layer / layer (C) /
A typical example is an adhesive resin layer / layer (B) . When the layer (B) is provided as the innermost layer and the outermost layer , the respective resins may be different or the same.

In the present invention, the water content of the layer (A) is not particularly limited, but may be 0.001-
Preferably, it is within 10% by weight.

Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto.

[0041]

EXAMPLES Example 1 Ethylene content of 44 mol%, saponification degree of 99.4%, melt index (MI 190 ° C., 2160 g load) 5.
5g / 10min. EVOH (KURARAY EVAL EP-
E105) 80 parts by weight, 90 as an aromatic diamine component
20 parts by weight of an aromatic polyamide resin (Lenny 6001 manufactured by Mitsubishi Gas Chemical Co., Ltd.) using mol% of meta-xylylenediamine and 10 mol% of ortho-xylylenediamine and adipic acid as a dicarboxylic acid component was used in a twin-screw type. The mixture was placed in a vented extruder of 30 mmφ and extruded at 200 ° C. under a nitrogen gas atmosphere to form pellets. The melt index (MI) of the obtained pellets is 28 g / 10 mi.
n.

Using the above pellets as a composition for an EVOH layer, a four-layer, five-layer coextrusion apparatus was used to prepare a raw sheet consisting of five layers. The layer configuration of the raw sheet is as shown in Table 2. The obtained sheet was applied to a pantograph-type biaxial stretching machine, and simultaneously biaxially stretched at 70 ° C. at a stretching ratio of 3 × 3 times.

Table 3 shows the properties of the obtained heat shrinkable multilayer film. Example 2-5, Comparative Example 1-4 Except that the composition of the EVOH layer was changed as shown in Table 1, and the layer structure of the raw sheet was changed as shown in Table 2, heat was applied in the same manner as in Example 1. A shrinkable multilayer film was made.

The properties of the obtained heat-shrinkable multilayer film are shown in Table 3. Example 6 Each resin constituting the raw sheet was separately extruded with a plurality of extruders, supplied to an annular die, and co-extruded with the layered sheet shown in Table 2. The compositions shown in Table 1 were used as the composition of the EVOH layer. The tubular body extruded from the die was cooled in a cooling bath at 10 ° C. to obtain a tubular laminate having a folding width of 150 mm and a thickness of 900 μm. The laminate is passed through a heating tank adjusted to 80 ° C., heated and heated, and then stretched 2.5 times in the longitudinal direction and 2.5 times in the transverse (diameter) direction by the air sent into the tubular laminate. did. The obtained biaxially stretched film had a folding width of about 375 mm and a thickness of 140 μm.

Table 3 shows the properties of the obtained heat-shrinkable multilayer film.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

The heat-shrinkable multilayer film of the present invention has uniform heat-shrinkability and good dimensional stability, has excellent adhesion to the contents during the heat-shrink operation, and has a gas barrier property. Good in properties, fragrance retention and organic solvent resistance. Further, when producing the heat-shrinkable multilayer film of the present invention, it can be produced without excessive stretching orientation because of extremely good stretchability,
Also, because of good thermal stability, there is no generation of gels and bumps,
Good transparency can be obtained.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (5)

(57) [Claims] 1. An ethylene content of 20-60 mol%,
Ethylene-vinyl alcohol copolymer having a degree of polymerization of 90% or more
10-95% by weight and aromatic polyamide resin 5-9
Ethylene-vinyl alcohol copolymer comprising 0% by weight
Composition layer (A), ethylene and vinyl ester monomer
Copolymer, aliphatic unsaturated carboxylic acid, aliphatic unsaturated
The copolymer of ethylene and a monomer selected from
Polymer, ionomer resin, linear low density polyethylene,
Linear low density polyethylene and ethylene-vinyl acetate copolymer
Resin mixed with body, Vicat softening point 9 at density 0.91 or less
Ultra low density polyethylene of 5 ° C or less, density of 0.91 or less
Ultra low density polyethylene with Vicat softening point of 95 ° C or less
Mixed resin with the amount of linear low-density polyethylene, and
Crystalline propylene-ethylene copolymer and polypropylene
A small number selected from the group consisting of mixed resins with elastomers
At least each layer (B) made of one type of resin
Layer (B) as the innermost layer and at 90 ° C.
When the area shrinkage when immersed in hot water for 1 minute is 10% or more
Some heat shrinkable multilayer films. 2. The polyamide resin layer (C) is further reduced.
And one layer, and the layer (C) is disposed outside the layer (A).
The heat-shrinkable multilayer film according to claim 1, wherein
Lum. 3. A polyamide tree of a polyamide resin layer (C).
The heat according to claim 2, wherein the fat is an aromatic polyamide resin.
Shrinkable multilayer film. 4. An ethylene content of 20-60 mol%,
Ethylene-vinyl alcohol copolymer having a degree of polymerization of 90% or more
10-95% by weight and aromatic polyamide resin 5-9
Ethylene-vinyl alcohol copolymer comprising 0% by weight
Composition layer (A), ethylene and vinyl ester monomer
Copolymer, aliphatic unsaturated carboxylic acid, aliphatic unsaturated
The copolymer of ethylene and a monomer selected from
Polymer, ionomer resin, linear low density polyethylene,
Linear low density polyethylene and ethylene-vinyl acetate copolymer
Resin mixed with body, Vicat softening point 9 at density 0.91 or less
Ultra low density polyethylene of 5 ° C or less, density of 0.91 or less
Ultra low density polyethylene with Vicat softening point of 95 ° C or less
Mixed resin with the amount of linear low-density polyethylene, and
Crystalline propylene-ethylene copolymer and polypropylene
A small number selected from the group consisting of mixed resins with elastomers
At least each layer (B) made of one type of resin
Heating temperature of 50-140 ° C, the vertical
And / or stretch 1.3-9 times each sideways
The heat-shrinkable multilayer film according to claim 1, wherein
Production method. 5. An ethylene content of 20-60 mol%,
Ethylene-vinyl alcohol copolymer having a degree of polymerization of 90% or more
10-95% by weight and aromatic polyamide resin 5-9
Ethylene-vinyl alcohol copolymer comprising 0% by weight
A composition layer (A), a polyamide resin layer (C),
Of vinyl ester and vinyl ester monomer, aliphatic unsaturation
Selected from carboxylic acids and aliphatic unsaturated carboxylic esters
Copolymer of monomer and ethylene, ionomer tree
Fat, linear low density polyethylene, linear low density polyethylene
Mixed resin of ethylene and ethylene-vinyl acetate copolymer, density
Ultra-low density poise with 0.91 or less and Vicat softening point of 95 ° C or less
Polyethylene, density 0.91 or less, Vicat softening point 95 ° C
The following ultra low density polyethylene and a small amount of linear low density polyethylene
Mixed resin with styrene, and crystalline propylene-ethylene
Mixing of propylene copolymer and polypropylene elastomer
At least one resin selected from the group consisting of resins
Having at least one layer (B) each consisting of
At a heating temperature of 50-140 ° C and vertically and / or horizontally.
3. The film is stretched 1.3 to 9 times.
Or a method for producing a heat-shrinkable multilayer film according to item 3.