JPH02258341A - Multi-layer structure - Google Patents

Abstract

PURPOSE:To manufacture a multi-layer structure of improved resistance to through-pin holes generated by flexing fatigue, resistance to gas barrier layer pinholes by providing a thermoplastic polyurethane layer at least on one surface of an ethylene - vinyl acetate copolymer saponified layer having specified ethylene content and saponification degree and satisfying a specified formula. CONSTITUTION:A thermoplastic polyurethane layer (B) is laminated directly at least on one surface of an ethylene - vinyl acetate saponified material layer (A), a multi-layer structure to satisfy formulae I - V manufactured by the coextrusion method when specifying the ethylene content of the layer (A) as mol % (a), the thickness of the layer as bmu, content N of the layer (B) as c weight % and the thickness of layer as dmu, and further hydrogen ion concentration pH of (A) as e, and alkali metal ion concentration of (A) as fppm. Resistance to through-pinholes and resistance to gas barrier layer pinholes can be improved by said arrangement. The ethylene content of the ethylene - vinyl acetate saponified material is 20 - 60mol %, and saponification degree of vinyl acetate is 90% or more.

Description

[Detailed Description of the Invention] A. Part 1 The present invention relates to a gas barrier multilayer structure,
Especially for food packaging applications that require high gas barrier properties, penetration pinhole resistance, and gas barrier layer pinhole resistance.
Suitable for use in industrial materials, daily necessities, and medical applications.

Note that penetration pinhole resistance here refers to the pinhole resistance that penetrates the entire layer against bending fatigue. Gas barrier layer pinhole resistance refers to the pinhole resistance of the gas barrier layer against bending fatigue. means.

1) Ethylene-vinyl acetate saponified material (EVOH) has the highest gas barrier properties among thermoplastic resins, and is used in a wide range of fields for the purpose of blocking gas permeation. It is used in large quantities.

However, EVOH single-layer products have the disadvantage of poor flexibility and reduced gas barrier properties due to the formation of pinholes due to bending during transportation.

Therefore, methods have been taken to overcome this drawback by softening the resin by laminating or blending it with other thermoplastic resins. Also, as stated in Japanese Patent Application Laid-Open No. 52-77160,
There is a method of blending ethylene-vinyl acetate copolymer or a partially saponified product thereof with OH. At first glance, these methods seem to overcome these drawbacks, but they are only used in limited fields for the following reasons.

In other words, although the film obtained by the above-mentioned lamination has some improvement in the penetration pinhole resistance against bending fatigue, a sufficient practical effect is not obtained, and the pinhole resistance of the gas barrier layer is poor. There was a problem.

Furthermore, films obtained by blending as described above have problems in terms of transparency and deterioration of gas barrier properties due to intralayer delamination and whitening due to bending fatigue. Therefore, in any case, the current situation is that there is no material that satisfies both penetration pinhole resistance and gas barrier layer pinhole resistance. On the other hand, thermoplastic polyurethane (TPU) and EVO
Regarding the multilayer structure laminated with H, JP-A-58-22
163, descriptions regarding the ethylene content of EVOH, pH1 alkaline metal ion concentration, nitrogen content of TPO, and thickness structure of each layer as described in (1) to (V) of the present invention, and Not only is there no mention of silicon-modified EVOH, but the purpose of the invention described in the same patent is to improve the gas barrier properties of TPU as a base material for use in airships, etc., and the penetration-resistant pin of the present invention The technical idea is different from that aimed at improving hole properties and gas barrier layer pinhole properties. In addition, the idea of using a laminate of TPU and gas barrier materials (mainly PVDC, polyamide, polyacrylonitrile) for biaxial stretching and shrinking purposes (Japanese Patent Publication No. 10193/1982, 273849/1984) is publicly known. However, not only is there no mention of EVOH, but the technical idea is fundamentally different from the present invention, which aims to improve the penetration pinhole resistance and gas barrier layer pinhole resistance.

Furthermore, regarding the use of laminates of TPU and gas barrier materials (PVDC, polyester, polyamide, polyacrylonitrile, EVOH) in vehicle tubes,
249737 and Japanese Patent Application Laid-Open No. 63-77740, the technical idea is not only different from the present invention which aims to improve penetration pinhole resistance and gas barrier layer pinhole resistance, but also Tpu When stacking EVOH and
Blend EVOH layer and TPU, or blend TPU and EVO
Since a multilayer structure is obtained through an EVA-based adhesive resin between H, a multilayer structure in which the specific EV OH, TPU of the present invention is directly laminated at a specific thickness ratio is a multilayer structure. The structure of the structure is different.

Problems to be Solved by C1 The object of the present invention is to provide a multilayer structure with high gas barrier properties that has greatly improved resistance to pinholes caused by bending fatigue and gas barrier layer pinhole resistance.

The inventors of the present invention conducted intensive studies for D', and surprisingly found that EV
In a multilayer structure in which a thermoplastic polyurethane (TPU) (B) layer is directly laminated on at least one side of the OH (A) layer, the ethylene content of the EVOH (A) layer in the multilayer structure is a (mol%), The thickness of the layer (the total thickness if there are multiple layers) is b (μ), the N content of the T P U (B) layer is C (wt%), the thickness of the layer (the total thickness if there are multiple layers) is d (μ), the hydrogen ion concentration (pH) of EVOH (A) is e, and the alkali metal ion concentration of EVOH (A) is f (ppm), then the following (I
It has been found that by obtaining a multilayer structure satisfying the formulas ) to (V), particularly by coextrusion, the penetration pinhole resistance and the gas barrier layer pinhole resistance can be greatly improved.

l≦C≦7 60≦aXc≦250 ... (I) ... (I[) 3.8≦e≦5.8
... (IV) 5≦f≦50
(V) Even more surprisingly, the silicon compound units are o, oo as the EVOH.
Silicon-modified EVOH containing os~0.2 mol%
It has been found that by using this, not only the penetration pinhole resistance but also the gas barrier layer pinhole resistance is further improved.

The EVOH used in the present invention has an ethylene content of 20 to
The saponified ethylene-vinyl acetate copolymer has a saponification degree of 60 mol%, preferably 25 to 60 mol%, and the degree of saponification of the vinyl acetate component is 90% or more, preferably 96% or more. When the ethylene content is less than 20 mol%, the molding temperature becomes close to the decomposition temperature, making molding difficult.

On the other hand, if the ethylene content is 60 mol% or more, the gas barrier properties will deteriorate, which is not preferable. Furthermore, EVOH in which the degree of saponification of the vinyl acetate component is less than 96%, particularly less than 90%, is undesirable because gel-like substances tend to occur frequently and gas barrier properties are low.

Furthermore, the hydrogen ion concentration of E V OH (A) is (IV)
As shown in the formula, it is important that the value is 3.8 to 5.8, preferably 3.8 to 5.5.

If the pH of E V OH (A) is less than 38, a lot of gel-like substances will be generated during extrusion molding, and if the pH exceeds 5.5, problems will arise in interlayer adhesion with TPU, which is not preferable.

Here, the pH of E V OH (A) is the pH of E V OH (A) in the layer (A).
VOHlGg (pellet form) in 50cc of pure water at 95℃
This is the value obtained by measuring I)T(in water) with a pH meter after leaving it for 3 hours.

Furthermore, it is important that the alkali metal ion concentration of EV OH (A) is 5 to 50 ppm as shown in formula (V). The preferred amount is 10 to 20 ppm't'. EV
If the alkali metal ion concentration of OH (A) is less than 5 pp- or exceeds 50 pp-, the interlayer adhesion with TPU will deteriorate, causing problems with the gas barrier layer and pinhole properties, so it is preferable. do not have. here,
The alkali metal salt concentration is a value obtained by incinerating the E V OH (A) in a crucible and measuring the alkali metal ion concentration in an aqueous solution of the resulting material by atomic absorption spectrometry.

To adjust the pH and alkali metal salt concentration of EVOH, add acidic substances or alkali metal salts to EVOH, respectively.
E can be added directly to the OH and mixed, or in an aqueous solution prepared by dissolving the acidic substance and the alkali metal salt in water.
A method of immersing VOH is exemplified.

Acidic substances include succinic acid, adipic acid, benzoic acid,
Examples include organic acids such as capric acid, citric acid, lauric acid, and acetic acid, anhydrous acids such as boric acid and phosphoric acid, and amino acids such as aspartic acid, aminobenzoic acid, and glutamic acid, but acetic acid is preferably used. . On the other hand, examples of the alkali metal salt include potassium dihydrogen phosphate, sodium dihydrogen phosphate, potassium acetate, and sodium acetate, and preferably potassium dihydrogen phosphate and sodium dihydrogen phosphate are used.

Furthermore, this EVOH has a silicon compound in the molecule with 0.0
It is more desirable to contain 0.005 to 0.2 mol%.

When such EVO containing silicon compound units is used, it is preferable because the interlayer adhesion of the multilayer structure is increased, and the penetration pinhole resistance and gas barrier layer pinhole resistance are improved.

Further, as the EVOH containing silicon compound units, it may be preferable to use a mixture of EVOH containing silicon compound units and EVOH containing no silicon compound units. Examples of the silicon compound unit contained in EVOH include the following (1), (If), and (TI[).

[However, here, n is 0 to L, m is 0 to 2, R1 is a lower alkyl group, an allyl group, or a lower alkyl group having an allyl group, and Rz is an alkoxyl group having 1 to 40 carbon atoms; may have an oxygen-containing substituent. Rs is hydrogen or a methyl group, R4 is hydrogen or a lower alkyl group, R' is an alkylene group or a divalent organic residue in which chain carbon atoms are interconnected by oxygen or nitrogen, R' is hydrogen, halogen, or lower alkyl basis,
an allyl group or a lower alkyl group substituting an allyl group, R
7 is an alkoxyl group or an acyloxyl group (herein, the alkoxyl group or acyloxyl group may have a substituent having oxygen or nitrogen), R' is hydrogen, halogen, lower alkyl group, allyl group, or allyl group Lower alkyl group having R1 is a lower alkyl group.

] More specifically, R1 is a lower alkyl group having 1 to 5 carbon atoms, an allyl group having 6 to 18 carbon atoms, or an allyl group having 6 to 18 carbon atoms.
Represents a lower alkyl group having 1 to 5 carbon atoms and having an allyl group of ~18, R4 represents a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, and R1 represents an alkylene group or chain having 1 to 5 carbon atoms. Represents a divalent organic residue in which carbon atoms are mutually bonded by oxygen or nitrogen, and R' is hydrogen, halogen, a lower alkyl group having 1 to 5 carbon atoms, an allyl group having 6 to 18 carbon atoms, or a carbon number 1 with 6 to 18 allyl groups
~5 lower alkyl group, R' represents an alkyl group or acyloxyl group having 1 to 40 carbon atoms (here, the alkoxyl group or acyloxyl group may have a substituent having oxygen or nitrogen). , R1 is hydrogen,
Halogen, lower alkyl group having 1 to 5 carbon atoms, 6 to 5 carbon atoms
18 allyl group or a lower alkyl group having 1 to 5 carbon atoms having an allyl group having 6 to 18 carbon atoms, and R1 represents a lower alkyl group having 1 to 5 carbon atoms. Vinyltrimethoxysilane, vinyltriethoxysilane, etc. are preferably used.

In addition, the EVOH may be copolymerized with propylene, butylene, N-vinylpyrrolidone compounds, plasticizers, heat stabilizers, ultraviolet absorbers, anti-participants, colorants, fillers, etc. to the extent that the effects of the present invention are not limited. You are free to blend ra etc.

Next, the TPU used in the present invention satisfies the above formula (1) because the nitrogen content in the TPU has a large effect on the penetration pinhole resistance and gas barrier layer pinhole resistance in lamination with EVOH. This is very important. If the nitrogen content exceeds 7% by weight, the gel/
Streaks are likely to occur, and there is little effect of improving penetration pinhole resistance and gas barrier layer pinhole resistance, and there is even a tendency for them to worsen. On the other hand, when the nitrogen content is 1% by weight without grooves, the effect of improving the penetration pinhole resistance and gas barrier layer pinhole resistance is reduced, probably due to poor adhesion to EVOH. More preferably, it is 1 to 6% by weight. Further, a general elemental analysis method is used as a method for measuring the nitrogen content.

The TPU used in the present invention is soluble and usually consists of two or three components such as a high molecular weight diol, an organic diisocyanate, and/or a low molecular weight diol.

Details of each component are described below.

Polymer diols are diols of polymer compounds obtained by polycondensation, addition polymerization (for example, ring-opening polymerization), polyaddition, etc. Typical examples include polyester diol, polyether diol, polycarbonate diol, or these. Cocondensates (e.g. polyester,
ether diol). These may be used alone or in combination of two or more.

The above polyester diols include ethylene glycol, propylene glycol, 1,4-butanediol, 1
．． 5-bentanediol, 3-methyl 1,5-bentanediol, 1,6-hexanediol, neopentyl glycol, 2-methylpropanediol, etc. with 2 carbon atoms
~10 alkane diols or mixtures thereof and 4 to 1 carbon atoms such as glutaric acid, adipic acid, pimelic acid, superric acid, sebacic acid, terephthalic acid, isophthalic acid, etc.
Saturated polyester diols obtained from 2 aliphatic or aromatic dicarboxylic acids or mixtures thereof, or polylactone diols such as polycaprolactone glycol, polypropiolactone glycol, and polyvalerolactone glycol are preferably used.

As the polyether diol, polyalkylene ether diols such as polyethylene ether glycol, polypropylene ether glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol are preferably used.

Furthermore, as the polycarbonate diol, 1.4-
Butanediol, 1.5-bentanediol, 1.6-
Hexanediol, 1.8-octanediol, 1.1
Preferably used is a polycarbonate diol obtained by condensation polymerization of an aliphatic or alicyclic diol having 2 to 12 carbon atoms such as 0-decane diol, or a mixture thereof with diphenyl carbonate or phosgene.

The average molecular weight of these polymer diols is 500-3, G
oo, preferably within the range of 500 to 2,5410. If the average molecular weight is too small, the compatibility with the organic diisocyanate will be too good and the resulting polyurethane will have poor elasticity, while if the average molecular weight is too large, the compatibility with the organic diisocyanate will be poor and mixing during the polymerization process will not be successful. Otherwise, lumps of gel-like material occur and stable polyurethane cannot be obtained.

The second raw material, low molecular weight diol, has a molecular weight of 5.
Low molecular weight diols less than 00, such as ethylene glycol, propylene glycol, 1,4-butanediol,
Aliphatic, alicyclic or aromatic diols include 1,5-pentane glycol, 3-methylpentane glycol, 1,6-hexanediol, and 1,4-bishydroxyethylbenzene. Even if these are used alone, 2
You may use a combination of more than one species.

Examples of organic diisocyanates include 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, 2
．． 2°-dimethyl-4,4°-diphenylmethane diisocyanate, 1.3- or 1.4-bis(isocyanatomethyl)benzene, 1.3- or 1.4-bis(
Aromatic, alicyclic or aliphatic diisocyanates such as methyl isocyanate) cyclohexane, 4.4°-dicyclohexylmethane diisocyanate and isophorone diisocyanate are mentioned.

These organic diisocyanates may be used alone or in combination of two or more.

The nitrogen content in the TPU used in the present invention is determined by appropriately selecting the proportions of high molecular diol, low molecular diol and organic diisocyanate.

Further, when producing TPU, an appropriate catalyst may be used to promote the reaction between the organic diisocyanate and the diol, if necessary. Furthermore, various additives such as colorants, fillers, antioxidants, and ultraviolet absorbers or lubricants may be added depending on the purpose.

Furthermore, in the present invention, it is also important to satisfy the above formulas (n) to (II).

λ×c in equation (II) is a parameter related to the affinity between EVOH and TPU, and ! *Even if the value of aXc is less than 6, 2
Even if it exceeds 50, the penetration pinhole resistance and gas barrier layer pinhole resistance deteriorate, probably because the interlayer adhesion between EVOH and TPU is poor. Preferably, the number is 60 or more and 230 or less.

In addition, formula (II) is a formula related to the thickness composition ratio of each layer and the nitrogen content of the TPU, and if it is less than □-0.02, the gas barrier property will decrease, probably because there is a problem with resin flow during coextrusion film formation. However, if it exceeds -+ 0.56, a problem will occur with the flexibility of the multilayer structure, so if the penetration pinhole resistance and gas barrier layer pinhole resistance are low, a material of □+0.12 or less is used. be done.

It is possible to employ the lamination of the E V OH (A) layer and the T PU (B) layer, such as a niha co-extrusion method, a dry lamination method, an extrusion lamination method, a co-extrusion lamination method, etc., but the co-extrusion method is also advantageous in its use. can. (A) layer and (B
) It is effective to directly laminate layers (A) and (B) without providing an adhesive between the layers. However, the use of an interlayer adhesive is not excluded as long as it does not impede the purpose of the present invention.

The thickness of the EVOH layer (before stretching) is 2-200μ, more preferably 4-80μ. On the other hand, the thickness of TPU laminated with EVOH is 4 to 800μ, preferably 4 to 40μ.
It is 0 μm, more preferably 5 to 100 μm.

The structure of the multilayer structure is (A)/(B), (B) where EVOH is (A), TPU is (B), other thermoplastic resins are (C), and adhesive resin is (D). ) / (A
)/ (B), (A)/ (B)/ (A), (A)/
(B)/ (C), (C)/ (D)/ (A)/(
B), (C)/ (B)/ (A)/ (B)/ (C
), (C)/ (D)/(A)/ (B)/ (A)/
Examples include (D)/(C).

It is also possible to use the recovered material of the multilayer structure in at least one of these layers or in a layer independent of these layers.

Here, (C) includes polyamide resins, polyester resins, polycarbonate resins, polyether resins, polyvinyl chloride resins, ethylene-vinyl acetate copolymer resins, polyalkyl acrylate resins, and polyolefin resins. is used. If the above structure has two or more EVOH layers or two or more TPU layers, each of the two layers has a different EvoH or TP-U layer.
may be used, or the same may be used.

Further, (D) is not particularly limited as long as it can bond the EVOH layer and the thermoplastic resin layer, but it is preferable to add or graft an ethylenically unsaturated carboxylic acid or its anhydride (for example, maleic anhydride). Polyolefins (eg, polynyletine, polypropylene), ethylene-vinyl acetate copolymers, ethylene-acrylic acid ester (eg, methyl ester, ethyl ester) copolymers, and the like can be mentioned.

In the present invention, the multilayer structure includes a film, a sheet,
Bags obtained from pipes or films, cups obtained by thermoforming sheets (vacuum or pressure forming, etc.), parisons obtained from pipes, bottles obtained by stretch blowing parisons, bottles obtained by direct blowing. These are particularly suitable for use as food packaging materials.

Furthermore, the present invention also includes a heat-shrinkable film obtained by stretching and heat-setting the above-described multilayer structure as one of the deaf forms of the present invention. This heat-shrinkable film is obtained under conditions that satisfy the following formulas (Vl) to (■).

EvOH Tg≦g≦TPU hard segment Tg
...(■)4≦h≦12 ・
...(■)g+3℃≦ISg+20℃
...(■) g: Stretching temperature Tg Ni glass transition temperature h: Stretching ratio i: Heat setting temperature If the stretching temperature (g) is less than 78 of EVOH, cracks will occur in the film during stretching, and TPU When the hard segment Tg is exceeded, stretching unevenness becomes severe and the heat shrinkability of the obtained film decreases. More preferably, the following formula is satisfied.

If the Tg of EVOH +5℃≦gsTPU hard segment Tg-5℃ or the stretching ratio (h) (vertical x horizontal in the case of two-wheel stretching) is less than 4, the heat shrinkability of the film will decrease, and if it exceeds 12 During rolling, the film may tear or there may be problems with dimensional stability. More preferably, 6.5≦h
≦1! , 5. Further, as for stretching, at least uniaxial stretching is required, but two-wheel stretching is preferred.

Furthermore, if the heat setting temperature (+) after stretching is less than g+3°C, there will be a problem in the dimensional stability of the obtained shrink film, and if it exceeds g+20°C, the heat shrinkage rate of the obtained shrink film will decrease. . More preferably g+5℃≦i≦g+lo℃
It is. The heat setting time is 20 seconds to 10 minutes, preferably 30 to 5 minutes after the film reaches a predetermined heat setting temperature after the start of heat setting. The thickness of the film after the stretching heat treatment is the value obtained by dividing the thickness before stretching by the stretching ratio.

The heat shrinkage rate of the heat-shrinkable film thus obtained (
The area shrinkage rate) is 20 to 90%, preferably 30 to 80%. In addition, this heat-shrinkable film (A) layer and (B)
The interlayer adhesive strength (g/15mm) of the layers is 600 or more, preferably 700 or more. Here, the definitions of heat shrinkage rate (area shrinkage rate) and interlayer adhesive strength are as described below.

The present invention will be explained in more detail in Examples below, but the present invention is not limited thereto.

Dan-double JJL Example 1 E V OH (A) has an ethylene content of 32 mol%
, saponification degree 97.5%, melt flow index 1.
3g/win (190℃-2160g) Nomo17)
One part was immersed in an aqueous solution containing 0.1% by weight of acetic acid and 0.01% by weight of sodium hydrogen phosphate in 100 parts of ion-exchanged water for 3 hours, and after removing the liquid, was dried, and the pH in the resin was 4.0,
The sodium ion concentration adjusted to 15 PI) II was used. TPU (B) includes 65 parts by weight of polybutylene adipate obtained from 1,4-butanediol and adipic acid, 5 parts by weight of l,4-butanediol, and 4 parts by weight of polybutylene adipate obtained from 1,4-butanediol and adipic acid.
, 30 parts by weight of 4°-diphenylmethane diisocyanate, polyester T having a nitrogen content of 3.4% by weight.
PU was used. A TPU/EVOH/TPU film was obtained using the EVOH and TPU two types and three layer coextrusion sheet manufacturing equipment. The thickness composition at this time is 50/to/5
It was G(μ). Furthermore, the EVOH of the obtained film (
A) Layer ID E V OH (A) (7) pH is 4.5
There was a time.

Cut this film into 29.7 x 21 cm (A4 size), 20°C, 65% R, H, (relative humidity)
Using a Gelbolex tester under the conditions of
At the same time, the number of pinholes generated in the bent film is counted by subjecting it to bending fatigue for 5,000 times.
Manufactured by Mocon 0. The oxygen permeability coefficient was measured using a barrier measuring device. The results are shown in Table 1.

As a result, it was found that even after 1000 and 5000 bending fatigue cycles, no penetrating pinholes were generated and no deterioration in gas barrier properties was observed, indicating good penetration pinhole resistance and gas barrier layer pinhole resistance. Ta.

The obtained multilayer packaging material was heat-sealed and a cap was attached to obtain a packaging bag. A liquid food was placed in this packaging bag, and the mouth of the bag was sealed. A large number of these bags were packed into a cardboard box to create a back-in-box.

This back-in-box was subjected to aR test for 2 days at 20° C. and 60% RJI, and then subjected to a vibration test using a rotary vibration tester (vibration condition: 267 rpi+), but no damage was found.

Examples 2 to 7 and Comparative Examples 1 to 5 Multilayer films were obtained under the same conditions as in Example 1 except for the conditions shown in Table 1. The results are shown in Table 1.

In addition, polybutylene adipate, 1.4-butanediol and 4.4°-diphenylmethane diisocyanate compounds were prepared by changing the ratio of polymer diol and 1°-4-butanediol so that the isocyanate group and hydroxyl group were 1:1. These were blended to obtain TPUs with different nitrogen contents (N), which were used.

In the multilayer film of Example 5 using Si-E V OH, no penetrating pinholes were generated even after 10,000 bending fatigue cycles, and the oxygen permeability coefficient did not increase.

On the other hand, in Comparative Example 4, the ethylene content was 32 mol%, the saponification degree was 97.5%, and the melt flow index was 1.38.
/sin (190℃, 2taog) EVOH resin 1
0 parts of sodium hydrogen phosphate to 100 parts of ion-exchanged water.
．． immersed in an aqueous solution containing 1% for 3 hours, dried after removing the liquid,
A multilayer film using EVOH adjusted to a pH of 7.0 in the resin (EVOH 118 of the EVOH layer of the obtained film is 7.0) and a sodium ion concentration of 143 ppH has a pin contact with the gas barrier layer after 5000 bending fatigue cycles. Holes are generated and the oxygen permeability coefficient is 32cc/am''
・It has become bigger as a day-at meal.

Explanation of symbols and abbreviations in Table 1 below: λ: Ethylene content (mol%) of layer (A) b: (A
) layer thickness (μ) c: (B) nitrogen content (wt%) of layer d: (B)
) Layer thickness (μ) Polyester TPU (polybutylene adipate and 1
．． (consisting of 4-butanediol and 4,4°-diphenylmethane diisocyanate) = Lamilon U manufactured by Kuraray Co., Ltd. Polyether-based TPU (consisting of polytetramethylene ether glycol, 1.4-butanediol, and 4.4°-diphenylmethane diisocyanate) : (1) Lamilon U Si-EVOH manufactured by Kuraray: Contains vinyltrimethoxysilane 10.
Modified EvOHPA: Polyamide resin [Tsubamitsudo 10201 manufactured by Mitsubishi Chemical Industries, Ltd. EVA: Ethylene-vinyl acetate copolymer [Evaflex 460 manufactured by DuPont Mikata Polychemical Co., Ltd.] EV
OH”: pH 7.0 of EVOH used (EVOH layer CQE V OH4F of multilayer film) pH 7.0)
, sodium salt concentration 143 pP11. Ethylene content 3
2 mol%, saponification degree 97.5% Example 1-1 EVOH used in Example 1 as EVOH (A)
(7g69℃) as T P U (B) 1,
65 parts by weight of polybutylene adipate obtained from 4-butanediol and adipic acid, 5 parts by weight of 1,4-butanediol
Polyester TPU with a nitrogen content of 3.4% by weight obtained from 30 parts by weight of 4.4′-diphenylmethane diisocyanate (Tg of hard segment 101°C)
TPU/E is produced using two-type three-layer coextrusion sheet production equipment using
A VOH/TPU film was obtained, and the Conofilm was stretched using a simultaneous tenter at a temperature of 80°C and a degree of stretching of 3 in the vertical direction.
, Biaxial stretching was performed in the transverse direction at 3 (biaxial stretching ratio 9), and heat setting was performed at a heat setting temperature of 90° C. for 1 minute. The thickness configuration at this time was 20/25/20 (μ).

The properties of each film were evaluated using the methods shown in Table 1. The results are shown in Table 2.

Example 2-1 As EVOH, ethylene content 1i 32 mol%, saponification degree 99.5%, vinyltrimethoxysilane content o, oi
Mol% of modified EV OH (Si-EV OH) was used. Example 1 except for other conditions shown in Table 2-1
Same as -1.

Example 3-1 In addition to the structure of Example 1-1, a polyamide resin [Tsubamitsudo 1020 manufactured by Mitsubishi Chemical Industries, Ltd.] was used for both surface layers to obtain a three-type, five-layer coextruded film.

Other conditions other than those shown in Table 2 were those of Example 1-1 and Table 1. Excellent in sex.

Patent applicant RiRashi Co., Ltd.

Claims (1)

[Claims] (1) Ethylene content 20 to 60 mol%, saponification degree 90
% or more of saponified ethylene-vinyl acetate copolymer (A)
A multilayer structure having a thermoplastic polyurethane (B) layer on at least one side of the layer, and satisfying the following formulas (I), (II), (III), (IV) and (V). 1≦c≦7・・・・・・・・・・・・・・・・・・
・・・・・・(I) 60≦a×c≦250・・・・・・
・・・・・・・・・・・・・・・(II)c/50-0.0
2≦b/(b+d)≦c/50+0.56...(III
)3.8≦e≦5.8・・・・・・・・・・・・・・・
・・・・・・(IV)5≦f≦50・・・・・・・・・・・・
・・・・・・・・・・・・・・・(V) a: Ethylene content (mol%) of (A) b: Thickness of (A) layer (μ) c: Nitrogen content of (B) (% by weight) d: Thickness of (B) layer (μ) e: Hydrogen ion concentration (pH) of (A) f: Alkali metal ion concentration (ppm) of (A) (2)
The multilayer structure according to claim 1, wherein (A) contains 0.0005 to 0.2 mol% of silicon compound units. (3) The multilayer structure according to claim 1 or 2, which has the (B) layer on both sides of the (A) layer. (4) Claims 1 to 3 comprising the (A) layer on both sides of the (B) layer.
Multilayer structure according to any one item. (5) Claim 1, wherein the multilayer packaging material is a coextruded multilayer structure.
The multilayer structure according to any one of items 1 to 4.