JPH0647644B2 - Thermoforming resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A Field of Industrial Application The present invention is for thermoforming, which is free from pinholes, cracks, local uneven thickness, etc., and has excellent gas barrier properties during hot drawing, especially high-speed hot drawing operation. It relates to a resin composition.

B Conventional Technology Saponified ethylene-vinyl acetate copolymer (hereinafter referred to as EVOH
Is currently recognized as being effective in fields intended for use in packaging films for foods, etc., especially foods requiring a barrier property against oxygen, other products requiring aroma retention, etc. . However, the EVOH single film lacks toughness and has a drawback that it does not exhibit an effective barrier property against water and water vapor.

In order to improve these drawbacks, it is often used in the form of a multilayer structure in which a polypropylene layer and various heat sealant layers typified by ionomers and ethylene-vinyl acetate copolymers are laminated.

By the way, when a multilayer structure having an EVOH layer and a polypropylene layer (film, sheet, parison, etc.) is secondarily processed into a container or the like, particularly when stretch molding is performed at a temperature not higher than the melting point of EVOH, small voids, cracks,
Local uneven thickness often occurs, and as a result, the oxygen barrier property of the molded container is significantly deteriorated. Moreover, the appearance was also poor, and the container could not be used as a container for food or the like.

Conventionally, EVOH layer pinholes generated during heat drawing,
Various plasticizers are added to EVOH for the purpose of preventing cracking (JP-A-53-88067, JP-A-59-20345), and blends of polyamide resins (JP-A-52-141785 and JP-A-58-15).
4755, JP-A-58-36412) and the like have been studied, but none of them is sufficiently satisfactory.

Further, JP-A-52-101182 discloses that EVOH 95-99.5 with an ethylene content of 50 mol% or less and a saponification degree of 96 mol% or more.
With 50 to 90 mol% ethylene content in parts by weight, saponification degree 50 to 95
It is described that a polyolefin laminate is laminated on at least one side of a mixture layer containing 0.5 to 5 parts by weight of EVOH at a mol% to obtain a multilayer laminated container having excellent barrier properties and adhesiveness. EVOH like
It is difficult to prevent minute pinholes, cracks, uneven thickness, etc. even if the mixture layer of (1) is laminated with the PP layer and heated and stretched. This is also clear from the comparative example described later.

Therefore, it is an important issue to develop an EVOH having good molding characteristics that does not cause minute pinholes, cracks, uneven thickness, etc. in the EVOH layer when it is heat-stretched into a laminate of an EVOH layer and a polypropylene layer, particularly when it is heat-stretched at high speed. one of.

C. PROBLEMS TO BE SOLVED BY THE INVENTION EVOH has excellent properties as described above, but when a laminate with polypropylene is secondarily processed into a container, for example, cracks, pinholes,
Local uneven thickness etc. occurs, and the gas barrier property is greatly deteriorated.

In addition, it is poor in appearance and cannot be used as a food packaging container.

Therefore, the inventors of the present invention have developed a crack, a pinhole, or a crack in the EVOH layer that occurs when the laminated body is subjected to secondary processing without damaging the excellent gas barrier property of EVOH.
The present invention has been completed as a result of intensive studies aimed at developing a thermoforming resin composition having high gas barrier properties while preventing the occurrence of local uneven thickness.

D Means for Solving Problems According to the present invention, an ethylene-vinyl acetate copolymer saponification product (A) having an ethylene content of 45 to 60 mol% and a saponification degree of a vinyl acetate component of 96 mol% or more is 6 to 70 wt%. And ethylene content 25 ~
40 to 40% by weight, saponification product of ethylene-vinyl acetate copolymer (B) having a saponification degree of 96% or more of vinyl acetate component (B) of 94 to 30% by weight, and satisfying the following formulas (I) to (III): A thermoforming resin composition having a plurality of endothermic peaks in a melting curve measured by a differential scanning calorimeter.

1 ≦ E ′ (B) / E ′ (A) ……… (I) E ′ (A) ≦ 10 ⁹ dyne / cm ² ……… (II) 0.05 ≦ MI (A) / MI (B) ≦ 20 ……… (III) Various sheets having a polypropylene (PP) layer on one or both sides of the EVOH layer with an adhesive resin interposed therebetween are prepared, and by reheating and stretching operations, when the secondary processing is performed on a cup or a bottle, the appearance of the container and By measuring the gas barrier property, it is possible to judge the molding processing method of the EVOH layer and the superiority or inferiority of the gas barrier property. Therefore, the present inventors blended various plasticizers, polymers and the like with EVOH and measured the molding processability and gas barrier property of EVOH. As a result, an EVOH composition prepared by blending EVOH with polyamide or the like in an amount of 5 to 30% by weight is a blend of glycol-based or amide-based plasticizer, polyethylene-based, ethylene-vinyl acetate copolymer and maleic anhydride modified products thereof. It seemed that a better molded product without cracking or unevenness was obtained during thermoforming than the EVOH composition. However, when the oxygen gas barrier property of the container was measured, it was found to be worse than the gas barrier property of the original fabric, and even worse, the measured value varied greatly depending on the container, and sometimes the barrier property was 1/10 ~. Even things that deteriorate to 1/50 are recognized. This tendency is remarkable especially when the heat drawing speed during thermoforming is increased, when the thickness of the EVOH composition layer is increased, or when the draw ratio (drawing ratio) is increased.
Therefore, it poses a great problem in terms of reliability as a gas barrier container.

Therefore, as a result of further diligent studies, the inventors have blended a specific amount of EVOH (A) having an ethylene content of 45 mol% or more and EVOH (B) having an ethylene content of 40 mol% or less, and By using the resin composition satisfying the formulas (I) to (III) and having a melting curve by a differential scanning calorimeter having a plurality of endothermic peaks, regardless of the stretching speed,
It has been found that not only a thermoformed product that is good in appearance can be obtained, but also a thermoformed product that is less deteriorated in gas barrier properties and has less variation in measured values.

EVOH (A) used in the present invention has ethylene content
An ethylene-vinyl acetate copolymer saponified product having 45 to 60 mol%, preferably 45 to 55 mol%, and a saponification degree of the vinyl acetate component of 96 mol% or more. If the ethylene content is less than 45 mol%, cracks and pinholes are likely to occur during thermoforming, and the measured gas barrier properties also vary, which is not preferable.
On the other hand, when the ethylene content exceeds 60 mol%, the gas barrier property is deteriorated and the performance as a gas barrier container is insufficient, which is not preferable. Also, the degree of saponification of vinyl acetate component
EVOH of less than 96 mol% is not preferable because not only the gas barrier property is not sufficient but also the thermal stability is poor and gel is generated during film formation. The preferred degree of saponification is 98 mol% or more.

On the other hand, the other EVOH (B) used in the present invention has an ethylene content of 25 to 40 mol% and a saponification degree of the vinyl acetate component of 96.
If the content of ethylene in (B) is less than 25 mol%, the moldability is insufficient, and if it exceeds 40 mol%, the gas barrier property is also insufficient. If the saponification degree of (B) is less than 96 mol%, the gas barrier property will be insufficient.

In the present invention, the resin composition of EVOH (A) and (B) is a differential scanning calorimeter (scanning speed).
It is important that the melting curve with 10 ° C./min) has multiple endothermic peaks. A single peak will cause cracking and uneven thickness.

Next, the mixing ratio (weight ratio) of EVOH (A) and EVOH (B) is A / B = 6/94 to 70/30. When the mixing ratio is A / B <6/94, when molding container, crack,
Unevenness and pinholes are likely to occur, and the gas barrier properties vary greatly, which is not preferable. On the other hand, A / B>
In the case of 70/30, local uneven thickness is generated at the time of molding the container, which is not preferable in appearance. Preferably the range is 7/93 ≦ A / B ≦ 45/55.

Furthermore, in the present invention, EVOH (A) and EVOH
It is important that (B) satisfies the above formulas (I) to (III).

The dynamic viscoelasticity is greatly influenced by the ethylene content of the EVOH, the degree of saponification, the melt index, etc., but when E '(A)> 10 ⁹ dyne / cm ² , the crack is generated during container molding. However, pinholes are likely to occur, and the measured values of the gas barrier properties are not preferable. Further, E '(B) is preferably 10 ¹³ dyne / cm ² or less.
E when the melt index ratio is MI (A) / MI (B)> 20 or MI (A) / MI (B) <0.05
In the blend of VOH (A) and EVOH (B), the dispersed particles do not become minute and become non-uniformly mixed, and thus cracks and pinholes are likely to occur at the time of container molding, and the variation in gas barrier property is also large. Become. Where MI (A) and M
I (B) is 0.1 to 20 g / 10 minutes, preferably 1 to 15 g /
It is selected from the range of 10 minutes.

When measuring the melt index, the melting point is 190 ° C.
If the temperature is in the vicinity or exceeds 190 ° C, it is measured at multiple temperatures above the melting point under a load of 2160g, and the reciprocal of absolute temperature is plotted on the abscissa and the melt index is plotted on the semilogarithmic graph, and extrapolated to 190 ° C. The value thus obtained is taken as the melt index value.

Also, the dynamic viscoelasticity E'at the thermoforming temperature is E '(B) / E'
When (A) <1, local uneven thickness occurs during molding of the container, which is not preferable in appearance.

The preferred range of the above formulas (I) to (III) is as follows.

10 ≦ E ′ (B) / E ′ (A) …… (I ′) E ′ (A) ≦ 8 × 10 ⁸ dyne / cm ² … (II ′) 0.06 ≦ MI (A) / MI (B ) ≦ 18 (III ′) The blending method of EVOH (A) and EVOH (B) is not particularly limited, but EVOH (A)
And (B) are dry-blended and pelletized with a Banbury mixer single-screw or twin-screw extruder. If the blend is non-uniform, or if gels or lumps are mixed during the blending operation, the EVOH blend layer may be broken or uneven during thermoforming, especially during hot stretch molding. In the heat blending according to 1., it is preferable to use an extruder having a high degree of kneading, N ₂ seal at the hopper mouth, and low temperature extrusion.

On the other hand, when these are mixed, other additives (various resins, antioxidants, plasticizers, coloring agents, etc.) can be freely used within the range that the effects of the present invention are not impaired. In particular, as a measure against the thermal stability of the resin and the prevention of gel formation, it is preferable to add a hydrotalcite-based compound, a hindered phenol-based or a hindered amine-based thermal stabilizer in an amount of 0.01 to 1% by weight.

The EVOH composition of the present invention can be formed into any thermoformed product such as a film, a sheet, a tube or a bottle by a well-known melt molding method or compression molding method.
By stacking the composition on the PP layer, remarkable features are exhibited, and therefore this point will be described below.

The PP used in the present invention is not particularly limited, and polypropylene, block copolymers of propylene and other comonomers such as ethylene, or random copolymers, and further blends of the above resins Things can be given. Other thermoplastic resin (for example, other polyolefin such as polyethylene) may be blended with these PP.

As a method for obtaining a multilayer structure, the EVOH composition and P
P and P via an adhesive resin, extrusion laminating method, dry laminating method,
A co-extrusion laminating method, a co-extrusion sheet manufacturing method (such as a feed block or a multi-manifold method), a co-extrusion pipe manufacturing method, a co-injection method, various weld coating methods and the like are used to obtain a laminate, which is then thermoformed, for example, A method of reheating by a vacuum pressure air deep drawing machine, a biaxial stretching blow machine, etc. within a range not higher than the melting point of PP and performing a stretching operation (SP
PF molding), melt molding performed at a melting point of PP or higher, or a method of subjecting the laminate (sheet or film) to a biaxial stretching machine and heating and stretching, and further, EVOH composition and P
A method of co-injection biaxial stretching with P and the like can be mentioned.

Regarding the thickness constitution of the multilayer structure, a good molded product can be obtained in the multilayer structure in which the tensile tension ratio of the EVOH layer to the PP layer is 5 or less, preferably 1 or less at the thermoforming temperature, particularly the hot stretch molding temperature. . When the tensile ratio is 5 or more, the EVOH composition is also unfavorable because cracks, unevenness and the like are likely to occur. Here, the tensile tension of the PP layer of the multi-layer structure is a value measured at 100% elongation at the same temperature as the heat-stretching temperature at a tensile speed of 50 mm / min, a chuck interval of 50 mm, and a multi-layer structure before heating and stretching. The tensile tension of the EVOH layer is a value measured under the same conditions as described above for an EVOH single layer composed of a blend of (A) and (B). Further, these tensile tensions are obtained by subjecting the multilayer structure after heat drawing to hot pressing, releasing the drawing and returning it to the state before the heat drawing,
It is also possible to measure under the same conditions as described above.

The structure of the multilayer structure is as follows: EVOH composition layer / adhesive resin layer / PP layer, PP layer / adhesive resin layer / EVOH
Typical examples are composition layer / adhesive resin layer / PP layer. Here, the adhesive resin is not particularly limited as long as it can be stretch-molded at a melting point of EVOH or less and can bond the EVOH composition layer and the PP layer, but is preferably an ethylenically unsaturated carboxylic acid. Polyolefin (eg, polyethylene, polypropylene), ethylene-vinyl acetate copolymer, ethylene-, or its anhydride (eg, maleic anhydride) added or grafted
Examples thereof include acrylic acid ester (eg, methyl ester, ethyl ester) copolymers and the like.

In the present invention, a thermoformed article, particularly a heat-stretched multilayer structure is a container such as a cup or bottle obtained by heat-stretching as described above, a sheet or a film-like material, and heating means the multilayer structure. Can be left at the temperature necessary for heating and stretching for a predetermined time, and the multi-layer structure can be operated so as to be thermally substantially uniform. In consideration of operability, heating with various heaters and uniform The preferred method is The thermoforming temperature is 110 to 230 ° C, preferably 120.
It is selected from the range of up to 210 ° C. The heating operation may be performed at the same time as the stretching, or may be performed before the stretching. Stretching means an operation of uniformly forming a multilayer structure that has been heated thermally uniformly into a container, cup, sheet or film by chuck, plug, vacuum pressure, blow, etc., uniaxial stretching, biaxial stretching. Either (simultaneous or successive) can be used. The stretching ratio and the stretching speed can be appropriately selected according to the purpose. In the present invention, the high-speed stretching means that the stretching speed {stretching area ratio (%) / min} is 5 × 10 ⁵ % / min or more at a high speed. Alternatively, it means a method of uniformly thermoforming into a film. The thermoformed article thus obtained does not necessarily have to be oriented.

On the other hand, regarding the draw ratio, a remarkable effect can be expected in the present invention when the area ratio is 3 times or more. A suitable draw ratio is 3 to 60 times. The upper limit of the draw ratio is about 70 times, and if the draw ratio is 70 times or more, it becomes difficult to draw PP, and it is difficult to obtain a good multi-layer structure.

Further, in the present invention, the water content of the EVOH composition layer, which is one component of the multilayer structure during thermoforming, particularly heat stretching, is not particularly limited, but is 0.01 to
It is preferably within 10%, and more preferably 0.01-5%.
There is no particular limitation on the method of collecting scraps such as trims and defective containers generated during container molding. The scrub is crushed and, if it is hygroscopic, dried, and then dry-blended into the raw PP resin, the crushed scrap is pelletized, and then the dry-blended into the raw PP resin, and the crushed scrap and the raw PP resin are mixed. There are methods such as blending into pellets. Regarding the blend ratio of the raw material PP and the scrap, the higher the scrap ratio is, the more easily abnormalities such as uneven thickness, unevenness, cracks, and whitening occur during stretch molding.
Blended at a ratio of about 0%. At this time, in order to improve the dispersibility and thermal stability and to suppress the above-mentioned abnormalities during container molding,
Maleic anhydride modified polyolefins, metal soaps,
It may be preferable to blend a plurality of hydrotalcite compounds.

The thermoforming of the present invention thus obtained, in particular, the hot drawing, especially the high speed hot drawing multilayer structure does not show pinholes, cracks, and uneven thickness in the EVOH composition layer, and therefore has a very good gas barrier property. It is effective for very good tableware packaging containers with little variation or containers requiring aroma retention.

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

E Example 1 EVOH having an ethylene content of 50 mol%, a saponification degree of 99.4 mol%, a melt index (MI) (190 ° C.) of 16 g / 10 min.
Vibron (A) (Measured frequency by Toyo Boardwin
Dynamic viscoelasticity E '(A) (140 ° C) 10 ⁸ dyne /
It was cm ² . On the other hand, ethylene content 32 mol%, saponification degree 99.6 mol%, melt index (MI190 ° C) 1.5 g
Dynamic viscoelasticity of EVOH (B) / 10 minutes E '(B) (150
C) was 3 × 10 ⁹ dyne / cm ² . EVOH (A) and EV
OH (B) was blended at a weight ratio of A / B = 20/80 and extruded at 200 ° C. under N ₂ with a twin-screw screw type bent type 40φ extruder to form a pellet. 80 of the pellets obtained
It was dried at ℃ for 8 hours. Using this pellet, a feed block type 3 type 5 layer coextrusion device was used to prepare a sheet. The seat configuration is polypropylene on both outermost layers (Mitsubishi Noblen M
A-6) has a thickness of 800 .mu.m or an adhesive resin layer (Mitsubishi Petrochemical P-300F; maleic anhydride modified polypropylene) has a thickness of 50 .mu.m, and the innermost layer (center) is the EVOH layer 50 .mu.m. When this pellet was measured by DSC (scanning speed 10 ° C./minute), endothermic peaks were found at two points (150 ° C., 183 ° C.). 150 sheets obtained
Tensile tension at ℃ (tensile speed 50mm / min, check interval)
When 50%) was measured, the tension of the polypropylene layer at 100% elongation was 1.0 kg / 15 mm width. See also EVO
The tension of H single layer (50μ) under the same condition is 0.2kg / 15
The width was mm. That is, the tensile tension of the EVOH layer / polypropylene layer was 0.2. The sheet was placed in a vacuum pressure molding machine (stretching speed 9 × 10 ⁵ % / min, drawing ratio 1 stretched area ratio 7 times), and thermoformed (SPPF molding) at 150 ° C. The obtained molded product has good transparency and appearance,
No cracks and uneven thickness. 20 ℃ ・ 65% RH of this container
The gas barrier property was measured using a Model 10/50 manufactured by Mocon Co., and the oxygen permeation amount was 0.7 cc · 20 μ / m ² · 24 hr · a.
Not only does it show a very good gas barrier property with tm,
10 samples measured oxygen permeability variation when the (R = maximum value - minimum value) ^{0.1cc · 20μ / m 2 · 24hr} · atm
It was a very small and good barrier container.

Comparative Example 1 The procedure of Example 1 was repeated except that the blend ratio of EVOH (A) / EVOH (B) in Example 1 was changed to 4/94 weight ratio.

As a result, Kuratsuku, uneven thickness is large and also the gas barrier properties also has failed withstand greater use and ^{5cc · 20μ / m 2 · 24hr} · atm.

Comparative Example 2 The ethylene content is the same as the average ethylene content (36 mol%) of the blend (20/80) of EVOH (A) and EVOH (B) in Example 1. Single EVOH (D
SC single peak, MI 190 ° C. 4.0 g / 10 min, dynamic viscoelasticity E ′ 3 × 10 ⁸ dyne / cm ² ) was carried out in the same manner as in Example 1. As a result, there are many cracks and uneven thicknesses, and they cannot be used.

Example 2 EVOH having an ethylene content of 47 mol%, a saponification degree of 99.4 mol%, a melt index (MI 190 ° C.) of 10 g / 10 min.
Dynamic viscoelasticity E '(A) (180 ° C) of (A) is 10 ⁸ dyne / cm ²
It was as follows. On the other hand, ethylene content 27 mol%, degree of saponification
99.6 mol%, melt index (190 ℃) 1.3g / 1
0 minutes {(MI 210 ℃) 2.8g / 10 minutes; (MI 230
EVOH of the value obtained by extrapolation from 5.5 g / 10 min.
The dynamic viscoelasticity E '(B) (190 ° C) of (B) is 10 ⁹ dyne / cm ²
It was. A / B between EVOH (A) and EVOH (B)
= 10/80 by weight, and pelletized and made into a sheet as in Example 1. This pellet is DSC
When measured at (scanning speed 10 ° C / min), endothermic peaks were found at two points (198 ° C, 175 ° C). When the tensile tension of the obtained sheet at 190 ° C. was measured, the tension of the polypropylene layer at 100% elongation was 0.2 k.
The g / 15 mm width and the tension of the EVOH single layer (50 μ) under the same conditions were 0.1 kg / 15 mm width or less. That is,
EVOH layer / polypropylene layer tensile tension ratio is 0.5
It was. The sheet was vacuum-pressed and formed (stretching speed 6 × 10 ⁸
%, Draw ratio 1.8, draw area magnification 12 times),
Thermoforming was performed at 0 ° C. The obtained molded product is a crack,
There was no unevenness or uneven thickness, and the appearance was good. Also, the gas barrier property of this container is 0.4 cc.
² · 24hr · atm and (20 ℃ 65% RH) was good,
The variation (R) of oxygen permeation amount when measuring 10 samples
It was a very small and good gas barrier container with 0.1 cc · 20 μ / m ² · 24 hr · atm.

Comparative Example 3 In Example 2, EVOH (A) was used with an ethylene content of 47 mol%, a saponification degree of 99.4 mol%, and a melt index (MI).
190 ° C) 60 g / 10 minutes {MI (A) / MI (B) = 46.
2}, dynamic viscoelasticity E ′ (A) was changed to EVOH having 10 ⁸ dyne / cm ² or less, and the same operation as in Example 2 was performed. As a result, a large number of small thickness deviations were found in the molded container, and it could not be used in appearance.

Comparative Example 4 EVOH (B) in Example 1 was mixed with ethylene content 42 mol%, saponification degree 99.6 mol%, melt index (190
° C.) 20 g / 10 min, a dynamic viscoelasticity E '(B) in place of 1 × 10 ⁹ dyne / cm ² of EVOH (B), in the same manner as in Example 1 row Natsuta.
As a result, slight unevenness (uneven thickness) was observed in the molded container,
Moreover, the variation (R) of the measured value of the oxygen transmission amount is 1.2 cc.
As large as ^{· 20μ / m 2 · 24hr ·} atm it has failed withstand use.

Example 3 The same procedure as in Example 1 was carried out using the recovered product-containing polypropylene obtained by crushing the trim and the defective container after thermoforming in Example 1 and blending the polypropylene (MA-6) with 10% by weight. As a result, the appearance of the molded product is good, and the gas barrier property is such that the oxygen permeation amount is 0.7 cc · 20 μ / m.
The variation (R) of the measured value of ² · 24 hr · atm and the amount of oxygen permeation was as small as 0.1 cc · 20 μ / m ² · 24 hr · atm, and it was a good barrier container.

Comparative Example 5 In Example 1, EVOH (A) was mixed with ethylene content 52 mol%, saponification degree 70 mol%, melt index (MI).
190 ℃) 15g / 10min, EVOH of E '(A) 5 × 10 ⁷ dyne / cm ²
And the mixing ratio of EVOH (A) / EVOH (B) was changed to 4/96, and the same procedure as in Example 1 was performed. The obtained molded product has a large number of spots on the EVOH layer,
Also, a slight mark was recognized in the EVOH layer around the spot. As a result, the gas barrier property is 23c of oxygen permeation.
c ・ 20μ / m ²・ 24hr ・ atm, which is too high to be used.

Comparative Example 6 Instead of 20 parts by weight of EVOH (A) in Example 1, ethylene content 43 mol%, saponification degree 99.4%, MI 10 g /
For 10 minutes, the same procedure as in Example 1 was carried out except that 50 parts by weight of EVOH (E '(A) 2 × 10 ⁸ dyne / cm ² ) was used and 80 parts by weight of EVOH (B) was replaced with 50 parts by weight. Natsuta.

The gas barrier property of the container obtained as a result is the amount of oxygen permeation.
5.8cc ・ 20μ / m ²・ 24hr ・ atm is bad, and the variation (R) of the measured value of oxygen permeation amount is 1.0cc ・ 20μ
It was as large as / m ² · 24 hr · atm. In addition, local uneven thickness was generated in the container, which was not preferable in appearance.

Comparative Example 7 Instead of 20 parts by weight of EVOH (A) in Example 1, ethylene content 70 mol%, saponification degree 99.5%, MI 30 g / 10
The same procedure as in Example 1 was carried out except that 30 parts by weight of EVOH having E ′ (A) 5 × 10 ⁷ dyne / cm ² was used.

As a result, slight unevenness in thickness (uneven thickness) was observed in the molded container, and the gas barrier property was that the oxygen permeation amount was 6.5 cc · 20μ.
/ M ²・ 24hr ・ atm

Comparative Example 8 Ethylene content as EVOH (A) in Example 1 72
Mol%, saponification degree 40%, MI 4 g / 10 min, E '(A) 10 ⁷ d
The same procedure as in Example 1 was carried out except that EVyne of yne / cm ² was used.

As a result, unevenness (uneven thickness) was observed in the molding container, and the gas barrier property was that the oxygen permeation amount was 12 cc · 20 μ / m ² · 24 hr.
· Atm and bad, the oxygen permeation amount of variation of the measured value (R) is also ^{2.2cc · 20μ / m 2 · 24hr} · atm and size Katsuta.

Comparative Example 9 Instead of EVOH (A) in Example 1, ethylene content 60 mol%, saponification degree 99.5%, MI 9 g / 10 min, E '(A)
8 × 10 ⁷ dyne / cm ² of EVOH was used. Instead of EVOH (B), ethylene content was 29 mol%, saponification degree was 99.5%, MI
The same procedure as in Example 1 was carried out except that EVOH of 0.3 g / 10 minutes and E ′ (B) 4 × 10 ⁹ dyne / cm ² was used.

As a result, cracks and pinholes are generated in the molded container, and the gas barrier has an oxygen permeation amount of 8 cc · 20 μ / m ² · 2.
It was as bad as 4 hr · atm, and the variation (R) of the measured value of oxygen permeation was as large as 1.9 cc · 20 μ / m ² · 24 hr · atm.

Comparative Example 10 In Example 1, instead of EVOH (A), ethylene content 48 mol%, saponification degree 99 mol%, MI 12 g / 10
Min, E ′ (A) 9 × 10 ⁷ dyne / cm ² EVOH is used
Instead of OH (B), ethynelene content 31 mol%, saponification degree 99%, MI 0.5 g / 10 min, E '(B) 3 × 10 ⁹ dyne / cm ² E
Example 1 was repeated except that VOH was used.

As a result, unevenness (local uneven thickness) was observed in the molding container, and the gas barrier property was that the oxygen permeation amount was 9 cc · 20 μ / m ²
・ 24hr ・ atm is bad, and the variation (R) of measured value of oxygen permeation is 2.0cc ・ 20μ / m ²・ 24hr ・ at
It was as big as m.

Comparative Example 11 In Example 1, instead of EVOH (A), ethylene content 46 mol%, saponification degree 99.5%, MI 10 g / 10 min,
E ′ (A) (120 ° C.) 5 × 10 ¹⁰ dyne / cm ² of EVOH was used. Instead of EVOH (B), ethylene content was 30 mol%,
Saponification degree 99.5%, MI 1.5g / 10 minutes, E '(B) (130
C) 6 × 10 ¹⁰ dyne / cm ² of EVOH was used, and ethylene-propylene copolymer (Mitsubishi Nobrene Ex-6) was used instead of polypropylene (MA-6) at 130 ° C.
The same procedure as in Example 1 was carried out except that the thermoforming was carried out in.

As a result, cracks and pinholes are generated in the molded container, and the gas barrier property is an oxygen permeation amount of 8.5 cc · 20 μ / m.
^It is bad at ²・ 24hr ・ atm, and the variation (R) of the measured value of oxygen permeation amount is 2.0cc ・ 20μ / m ²・ 24hr ・ at
It was as big as m.

Comparative Example 12 In Comparative Example 11, instead of EVOH (B), ethylene content 30 mol% saponification degree 98 mol%, MI 1.5 g / 10 min,
E ′ (B) (130 ° C.) The procedure of Comparative Example 11 was repeated except that 4 × 10 ¹⁰ dyne / cm ² of EVOH was used. E '(B) / E'
(A) = 0.8.

As a result, cracks and pinholes are generated in the molding container, and unevenness (local uneven thickness) is generated, and the gas barrier property is an oxygen permeation amount of 9.5 cc · 20 μ / m ² · 24 hr · atm.
And the variation (R) in the measured oxygen transmission rate is 1.8.
It was as large as cc · 20μ / m ² · 24hr · atm.

G. EFFECTS OF THE INVENTION Thermoformed articles obtained using the resin composition of the present invention are cracked,
There is little unevenness in thickness, the gas barrier property is extremely excellent, and there are also few variations in the gas barrier property.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-60-173038 (JP, A) JP-A-60-161447 (JP, A) JP-A-60-32844 (JP, A) JP-A-56- 86949 (JP, A) JP 52-94382 (JP, A) JP 52-73984 (JP, A) JP 49-99686 (JP, A)

Claims (2)

[Claims] 1. An ethylene-vinyl acetate copolymer saponification product (A) having an ethylene content of 45 to 60 mol% and a saponification degree of a vinyl acetate component of 96 mol% or more and 6 to 70 wt% and an ethylene content of 25 to 40 mol. %, Saponification degree of vinyl acetate component 9
6 to 30 mol% of an ethylene-vinyl acetate copolymer saponification product (B) of 94 to 30% by weight, and (I) to
A thermoforming resin composition which satisfies the formula (III) and has a plurality of endothermic peaks in a melting curve by a differential scanning calorimeter. 1 ≦ E ′ (B) / E ′ (A) ………
(I) E ′ (A) ≦ 10 ⁹ dyne / cm ² ……… (II) 0.05 ≦ MI (A) / MI (B) ≦ 20 ……… (II
I) 2. A thermoforming resin composition according to claim 1, which satisfies the following (I ') to (III'). 10 ≦ E ′ (B) / E ′ (A) ………
(I ′) E ′ (A) ≦ 8 × 10 ⁸ dyne / cm ² ……… (I
I ′) 0.06 ≦ MI (A) / MI (B) ≦ 18 .... (II
I ′)