Ethylene copolymer molded structure and ethylene copolymer composition

The first molded structure of the present invention is formed from ethylene copolymer compositions comprising (A) 50-80% by weight of an ethylene/unsaturated ester copolymer, and (B) 50-20% by weight of an ethylene/vinyl alcohol copolymer having an apparent melt viscosity, as measured at 220.degree. C. and a rate of shear of 100 sec.sup.-1, smaller by 300-1000 Pa.multidot.s than that of said ethylene/unsaturated ester copolymer (A), said molded structures having a stratiform structure wherein said ethylene/vinyl alcohol copolymer (B) has been dispersed into said molded structure in the form of thin layers. The first ethylene copolymer compositions according to the invention are the same as those mentioned above, except that parts of the above-mentioned component (A) have been replaced by a graft modified product (C) of an ethylene/.alpha.-olefin copolymer, and are excellent in heat stability, film forming properties and extrusion kneading properties. The second molded structures according to the invention are formed from the first ethylene copolymer compositions as mentioned above, and have the same stratiform structures as in the first molded structures. The first and second molded structures mentioned above are excellent in gas barrier properties and pinhole resistance.

FIELD OF INDUSTRIAL APPLICATION 
This invention relates to ethylene copolymer molded structures and ethylene 
copolymer compositions and more particularly to molded structures 
comprising ethylene copolymer excellent in gas barrier properties and 
pinhole-free properties, and to ethylene copolymer compositions excellent 
in drawing properties at the time of molding, film-forming properties and 
heat stability. 
TECHNOLOGICAL BACKGROUND 
When molded into film or the like, ethylene/vinyl alcohol copolymers 
containing vinyl alcohol structural units in a high proportion exhibit 
excellent gas barrier properties, and hence they are used widely as 
packaging material. However, the ethylene/vinyl alcohol copolymers have 
such problems that they are liable to water absorption, poor in 
drawability as well as in heat resistance, and are difficult to mold at 
high temperature. In the molded articles obtained from the above-mentioned 
copolymers, there are such problems that they deteriorate in gas barrier 
properties on account of the water absorption properties of said 
copolymers, they are insufficient in impact resistance in a dry state and, 
moreover, they are poor in pinhole resistance. 
On that account, the ethylene/vinyl alcohol copolymers as mentioned above 
are used singly rarely if ever and are used usually in combination with 
other materials. As an example of the combination use referred to above, 
there may be mentioned a multi-ply laminates prepared by laminating an 
interlayer composed of the ethylene/vinyl alcohol copolymer with other 
materials. Further, there have been proposed numbers of methods intended 
to obtain modified compositions by blending the above-mentioned copolymers 
and other resins. In the blending methods as mentioned above, however, it 
is difficult to obtain ethylene/vinyl alcohol copolymer compositions in 
which the defect of said copolymer has been removed markedly when the 
ethylene/vinyl alcohol is used as a main component of the resulting blend. 
On the other hand, when the resin other than the ethylene/vinyl alcohol 
copolymer is used as a main component of the resulting blend, it has 
heretofore been difficult to obtain compositions excellent in gas barrier 
properties owing to the ethylene/vinyl alcohol copolymer. 
In recent years, there have been proposed molded articles excellent in gas 
barrier properties, said molded articles being obtained from 
ethylene/vinyl alcohol copolymer compositions prepared by blending 
ethylene/vinyl alcohol copolymers and other resins. For example, Japanese 
Patent Publn. No. 30104/1976 proposes molded structures having a 
stratiform structure and different in content of an ethylene/vinyl alcohol 
copolymer in the direction of thickness, said structures being obtained by 
molding a composition comprising polyolefin and ethylene/vinyl alcohol 
copolymers into a desired shape under specific conditions. Further, 
Japanese Patent L-O-P Publn. No. 121017/1980 discloses a stratiform molded 
article of polymer composition containing 60-95% by weight of polyolefin, 
vinyl alcohol (co)polymer and alkylcarboxyl-substituted polyolefin. The 
copolymers of polyolefin and ethylene/vinyl alcohol copolymers as 
disclosed in the publications cited above, however, are poor in 
compatibility and tend to become poor in moldability, and it is therefore 
not always easy to mold these polymers into thin-layer films, and the 
thin-layer films obtained, if any, are required to show a further 
improvement in gas barrier properties. 
The present invention is intended to solve such problems involved in the 
prior art as mentioned above, and an object of the invention is to provide 
ethylene copolymer molded structures excellent in gas barrier properties, 
pinhole resistance and the like. 
A further object of the invention is to provide ethylene copolymer 
compositions excellent in drawing properties, film-forming properties and 
heat stability at the time of molding thereof and, at the same time, 
excellent in gas barrier properties and pinhole resistance. 
DISCLOSURE OF THE INVENTION 
The first ethylene copolymer molded structure of the present invention 
comprises an ethylene copolymer composition comprising 
(A) 50-80% by weight of an ethylene/unsaturated ester copolymer having 
85-65% by weight of ethylene structural units, 15-35% by weight of 
unsaturated ester structural units, and a melt flow rate of 0.5-20 g/10 
min as measured at 190.degree. C. under a load of 2160 g, and 
(B) 50-20% by weight of an ethylene/vinyl alcohol copolymer having 50-20 
mol% of ethylene structural units, 50-80 mol% of vinyl alcohol structural 
units, and a melt flow rate of 0.5-30 g/10 min, 
said ethylene/vinyl alcohol copolymer (B) having an apparent melt 
viscosity, as measured at 220.degree. C. and a rate of shear of 100 
sec.sup.-1, smaller by 300-1000 Pa.multidot.s than that of said 
ethylene/unsaturated ester copolymer (A), and said ethylene/vinyl alcohol 
copolymer (B) being dispersed into said molded structure in the form of 
thin layers. 
The first ethylene copolymer composition of the invention comprises 
(A) 30-75% by weight of an ethylene/unsaturated ester copolymer having 
85-65% by weight of ethylene structural units, 15-35% by weight of 
unsaturated ester structural units, and a melt flow rate, as measured at 
190.degree. C. under a load of 2160 g, of 0.5-20 g/10 min, 
(B) 50-20% by weight of an ethylene/vinyl alcohol copolymer having ethylene 
structural units of 50-20 mol%, 50-80 mol% of vinyl alcohol structural 
units, and a melt flow rate, as measured at 210.degree. C. under a load of 
2160 g, of 0.5-30 g/10 min, and 
(C) 1-40% by weight of a graft-modified product of a noncrystalline or low 
crystalline ethylene/.alpha.-olefin copolymer having 60-90 mol% of 
ethylene structural units with an unsaturated carboxylic acid or its 
anhydride, 
said ethylene/vinyl alcohol copolymer (B) having an apparent melt 
viscosity, as measured at 220.degree. C. and a rate of shear of 100 
sec.sup.-1, smaller by 300-1000 Pa.multidot.s than that of said 
ethylene/unsaturated ester copolymer (A). 
The second molded structure of the invention comprises the ethylene 
copolymer compositions as mentioned above, said ethylene/vinyl alcohol 
copolymer (B) being dispersed into said molded structure in the form of 
thin layers.

This electron microscope was obtained by taking a photograph of the section 
of the first molded structure of the present invention by means of a 
scanning type electron microscope, said molded structure being obtained as 
a film of 50 .mu.m in thickness and dyed with osmic acid and ruthenium. 
In FIG. 1, black portions represent the ethylene/unsaturated ester 
copolymer (A) present as a matrix layer, and the ethylene/vinyl alcohol 
copolymer (B) is dispersed along the film surface in the form of thin 
layers, without uneven distribution, and is observed as a portion 
surrounded by discontinuous white lines. 
The molded structures of the invention have such a stratiform structure as 
mentioned above. 
BEST EMBODIMENT OF THE INVENTION 
The molded structures obtained from the ethylene copolymer compositions of 
the present invention, and said ethylene copolymer compositions are 
illustrated below in detail. 
The term "polymer" used in the present invention is intended sometimes to 
designate not only homopolymer but also copolymer. 
First, the ethylene copolymer compositions from which the molded structures 
of the present invention are formed are illustrated hereinafter. 
Molded structure 
The ethylene copolymer compositions of the invention comprises (A) an 
ethylene/unsaturated ester copolymer and (B) an ethylene/vinyl alcohol 
copolymer. 
The ethylene/unsaturated ester copolymer (A) used in the ethylene copolymer 
compositions of the invention comprises 85-65% by weight, preferably 
85-72% by weight of ethylene structural units and 15-35% by weight, 
preferably 15-28% by weight of unsaturated ester structural units. 
If the ethylene copolymer composition contains less than 15% by weight of 
the unsaturated ester structural units, said composition tends to decrease 
in gas barrier properties and, on the contrary, if said composition 
contains the unsaturated ester structural units in an amount exceeding 35% 
by weight, the molded structure resulting therefrom tends to decrease in 
strength. 
The ethylene/unsaturated ester copolymer (A) has a melt flow rate of 0.5-20 
g/10 min, preferably 1-15 g/10 min as measured at 190.degree. C. under a 
load of 2160 g. 
The ethylene/unsaturated ester copolymer (A) as illustrated above may be 
obtained by copolymerization of ethylene and unsaturated ester. In this 
case, the unsaturated ester used may be either carboxylic acid unsaturated 
ester or unsaturated carboxylic acid ester. Concretely, these unsaturated 
esters include, for example, vinyl acetate, acrylic ester and methacrylic 
ester. Ester components of acrylic ester or methacrylic ester are, for 
example, alkyl esters of 1 to 8 carbon atoms. Of these alkyl esters, 
preferred are methyl esters or ethyl esters. 
The ethylene/vinyl alcohol copolymer (B) used in the ethylene copolymer 
compositions of the invention comprises 50-20 mol%, preferably 45-25 mol% 
of ethylene structural units and 50-80 mol%, preferably 55-75 mol% of 
vinyl alcohol structural units. Such copolymers (B) as mentioned above may 
be obtained by saponifying the corresponding ethylene/vinyl acetate 
copolymer in such a proportion that the saponification value becomes not 
less than 95%, preferably not less than 99%. The ethylene/vinyl alcohol 
copolymers (B) have a melt flow rate of 0.5-30 g/10 min, preferably 1-20 
g/10 min as measured at 210.degree. C. under a load of 2160 g. 
The ethylene/vinyl alcohol copolymers (B) have an apparent melt viscosity, 
as measured at 220.degree. C. and a rate of shear of 100 sec.sup.-1, 
smaller by 300-1000 Pa.multidot.s, preferably smaller by 400-900 
Pa.multidot.s than that of the ethylene/unsaturated ester copolymers (A). 
By virtue of the fact that the ethylene copolymer composition is formed 
from the ethylene/unsaturated ester copolymer (A) and ethylene vinyl 
alcohol copolymer (B) having such a difference in apparent melt viscosity 
between them as shown above, said ethylene copolymer composition comes to 
be capable of forming a molded structure in which the ethylene/vinyl 
alcohol copolymer (B) has been dispersed in the form of thin layers 
without uneven distribution. 
The ethylene copolymer composition from which the first molded structure of 
the present invention is formed comprises the above-mentioned 
ethylene/unsaturated ester copolymer (A) and ethylene/vinyl alcohol 
copolymer (B), said copolymer (A) being present in an amount of 50-80% by 
weight, preferably 55-70% by weight, and said copolymer (B) being present 
in an amount of 20-50% by weight, preferably 30-45% by weight. 
The ethylene copolymer compositions having such constituents as mentioned 
above are excellent in heat stability, drawing properties and film-forming 
properties at the time of molding thereof. 
The first molded structures of the invention are formed from the ethylene 
copolymer compositions as illustrated above. 
The molded structures of the invention have such a structure in which the 
above-mentioned ethylene/vinyl alcohol copolymer (B) has been dispersed in 
the form of thin layers without uneven distribution. More particularly, 
the copolymer (B) forms discontinuous thin layer along the direction of 
surface of the molded structure, and the resulting molded structure has in 
its main portion a stratiform structure in which the copolymer (B) has 
been dispersed substantially without uneven distribution. Such a structure 
as mentioned above is shown in the aforementioned electron microscope of 
FIG. 1. 
Because of their stratiform structure as mentioned above, the molded 
structures of the invention are excellent in gas barrier properties though 
they have been formed from the compositions containing 50-20% by weight of 
the ethylene/vinyl alcohol copolymer (B). 
The molded structures of the invention are preferably those having a broad 
area and a relatively small thickness, and they may be of various shapes 
such as film, sheet, hollow container or the like. 
The molded structures of the invention have a thickness of usually 5-1000 
.mu.m, preferably 20-500 .mu.m, and they exhibit excellent gas barrier 
properties even when they are thin layers having a thickness of 30-50 
.mu.m. 
The molded structures as illustrated above may be molded out of the 
above-mentioned ethylene copolymer compositions of the invention. In that 
case, the molding operation is preferably carried out by kneading together 
the above-mentioned components (A) and (B) of the ethylene copolymer 
composition and then feeding the resulting kneaded product to a molding 
machine, though said molding operation may be carried out by continuously 
kneading and feeding said components (A) and (B). The kneading operation 
is preferably carried out usually under the conditions of a kneading 
temperature of 170.degree.-235.degree. C., a rate of shear of 10-2000 
sec.sup.-1, and a retention time of 10 sec to 5 min. 
The molding operation may be carried out by such a method that the molten 
ethylene copolymer composition flows in the direction of the face of the 
resulting molded structure. Concretely speaking, the molding of the 
ethylene copolymer compositions can be carried out by such a method as 
extrusion, blow molding, injection molding, injection-blow molding and 
vacuum forming. 
In preparing the molded structures from the ethylene copolymer compositions 
as illustrated above, said copolymer compositions may be incorporated with 
various additives according to the purpose for which the compositions are 
used. Such additives as may be used for the purpose include, for example, 
antioxidants, heat stabilizers, drying agents, nucleating agents, 
antistatic agents and in addition thereto barrier properties imparting 
fillers such as mica. The addition to the ethylene copolymer compositions 
of the drying agent is preferred, because a tendency that the 
ethylene/vinyl alcohol copolymer (B) component of the ethylene copolymer 
composition absorbs water to decrease the resulting molded structure in 
gas barrier properties can be relaxed. Further, the resulting molded 
structure can be further improved in gas barrier properties by loading the 
ethylene copolymer composition with mica. 
In the ethylene copolymer compositions of the invention used for forming 
the molded structures, it is presumed that because the apparent melt 
viscosity of the above-mentioned ethylene/vinyl alcohol copolymer (B) is 
smaller by 300-1000 Pa.multidot.s than that of the ethylene/unsaturated 
ester copolymer (A), the ethylene/vinyl alcohol copolymer is dispersed at 
the time of molding in the form of thin layers along the direction of the 
surface of the molded structure. 
The first molded structures of the invention are excellent in gas barrier 
properties and pinhole resistance and, moreover, they are markedly 
superior in water absorbing properties to the molded structures obtained 
from the ethylene copolymer compositions containing only the 
ethylene/vinyl alcohol copolymer (B). 
The first molded structures of the invention may be laminated with layers 
composed of other materials. Such materials as may be used herein include, 
for example, polyolefins such as high density polyethylene, medium density 
polyethylene, low density polyethylene, linear low density polyethylene, 
polypropylene and poly-4-methyl-1-pentene, polyesters such as polyethylene 
terephthalate and polybutylene terephthalate, thermoplastic resins 
represented by polyamides such as nylon-6 and nylon-6,6, thermosetting 
resins such as polyurethane, various elastomers, metallic materials such 
as aluminum foil, and paper. In the laminated structures mentioned above, 
one or two or more of the molded structure layer of the invention may be 
contained as a surface layer or interlayer of the laminated structure. 
Ethylene copolymer composition 
The first ethylene copolymer compositions of the present invention are 
illustrated hereinafter. 
The ethylene copolymer composition of the invention comprises the 
aforementioned ethylene/unsaturated ester copolymer (A), ethylene/vinyl 
alcohol copolymer (B) and the following graft-modified product of an 
ethylene/.alpha.-olefin copolymer (C). 
The graft modified product (C) of ethylene/.alpha.-olefin copolymer used in 
the invention may be obtained by modification of the 
ethylene/.alpha.-olefin copolymer with unsaturated carboxylic acid or its 
anhydride. 
The ethylene/.alpha.-olefin copolymer used herein comprises 60-90 mol%, 
preferably 70-85 mol% of ethylene structural units and 40-10 mol%, 
preferably 30-15 mol% of structural units derived from .alpha.-olefin 
other than ethylene. 
The .alpha.-olefin used herein includes concretely those having about 3-8 
carbon atoms, preferably propylene, 1-butene, 1-pentene and 
4-methyl-1-pentene. 
The ethylene/.alpha.-olefin copolymers used in the present invention are 
low crystalline or non-crystalline, and concretely have a crystallinity 
index, as measured by the X-ray diffractometry, of usually not more than 
30%, preferably not more than 20%. 
This ethylene/.alpha.-olefin copolymers desirably have a melt flow rate at 
190.degree. C. and a load of 2160 g of usually 0.3-50 g/10 min, preferably 
0.5-20 g/10 min. 
The unsaturated carboxylic acid or its anhydride used in graft modifying 
the above-mentioned ethylene/.alpha.-olefin copolymer includes concretely 
acrylic acid, methacrylic acid, fumaric acid, maleic acid, nadic acid, 
maleic anhydride, itaconic anhydride and nadic anhydride. Of the acids and 
anhydrides thereof, particularly preferred is maleic acid or maleic 
anhydride. 
The graft-modified product (C) of the ethylene/.alpha.-olefin copolymer is 
preferably modified so that the grafted amount becomes usually 0.03-7% by 
weight, preferably 0.05-5% by weight. 
Besides the graft modified product of the ethylene/.alpha.-olefin copolymer 
used in the ethylene copolymer compositions of the invention, graft 
modified products, for example, an ethylene/vinyl acetate copolymer 
graft-modified product are known. However, when graft modified products 
other than those of the ethylene/.alpha.-olefin copolymer are used as the 
graft modified products (C) in the invention, the gas barrier properties 
of the resulting molded structure sometimes decrease greatly depending 
upon the amount of the other graft modified product used in the ethylene 
copolymer composition. In contrast thereto, practically no decrease in gas 
barrier properties is observed in the resulting molded structure even when 
the graft modified product (C) of the ethylene/.alpha.-olefin copolymer of 
the invention is used in a relatively large amount in the ethylene 
copolymer composition of the invention. In addition, in an ethylene 
copolymer molded structure formed from an ethylene copolymer composition 
containing copolymers (A), (B), and a graft modified product (C) of a 
non-crystalline or low crystalline ethylene/.alpha.-olefin copolymer, the 
ethylene/vinyl alcohol copolymer (B) of the composition has been dispersed 
into the structure in the form of thin layers. 
The ethylene copolymer compositions of the invention comprise the 
above-mentioned ethylene/unsaturated ester copolymer (A) in amounts of 
30-75% by weight, preferably 40-65% by weight, ethylene/vinyl alcohol 
copolymer (B) in amounts of 20-50% by weight, preferably 30-45% by weight 
and graft modified product (C) in amounts of 1-40% by weight, preferably 
5-30% by weight. 
The ethylene copolymer compositions of the invention having such 
composition as mentioned above are excellent in heat stability, drawing 
properties and film forming properties at the time of molding thereof, and 
are capable of forming molded structures excellent in gas barrier 
properties and pinhole resistance. 
Since the ethylene copolymer compositions of the invention contain the 
graft modified product (C) of the ethylene/.alpha.-olefin copolymer in an 
amount as defined above, the ethylene copolymer compositions have been 
improved further in extrusion kneading properties and film forming 
properties. 
When the ethylene copolymer compositions contain large amounts of the graft 
modified product (C), the molded structure resulting therefrom sometimes 
decreases in gas barrier properties. In the case of the ethylene copolymer 
compositions of the invention containing the graft modified product (C) in 
such an amount as defined above, practically no decrease in gas barrier 
properties is observed in the molded structure resulting therefrom. 
The second molded structures of the invention are formed from the 
above-mentioned first ethylene copolymer as mentioned above. 
The second molded structures of the invention have a stratiform structure 
similar to that of the first molded structures of the invention as 
mentioned above. 
The second molded structures may take the same shapes as those of the first 
molded structures as mentioned above, and may be molded in the same manner 
as in the case of the first molded structures of the invention. 
The second molded structures may be obtained by using extruders having 
usual kneading functions, and it is not necessary to employ such extrusion 
conditions under which a laminar flow is formed. Further, a sheet-like 
molded structure obtained may be formed into a container of the desired 
shape by fabrication technique such as vacuum or air-pressure forming. 
EFFECT OF THE INVENTION 
In the first ethylene copolymer molded structures provided according to the 
present invention, the ethylene/vinyl alcohol copolymer (B) is dispersed 
in the form of thin layers without uneven distribution, hence the molded 
structures are excellent in gas barrier properties. Because of low water 
absorption properties, the first ethylene copolymer molded structures are 
small in dependence on humidity. Furthermore, the molded structures 
obtained as films and the like are excellent in pinhole resistance as 
well, and are useful as various packaging materials such as food wrap 
films. 
The first ethylene copolymer compositions of the invention comprise an 
ethylene/unsaturated ester copolymer (A) containing a specific amount of 
unsaturated ester structural units, an ethylene/vinyl alcohol copolymer 
(B) having an apparent melt viscosity varying by a specific value from 
that of said copolymer (A), and a graft modified product (C) of an 
ethylene/.alpha.-olefin copolymer, and hence the ethylene copolymer 
compositions are excellent in heat stability and drawing properties at the 
time of molding thereof and, at the same time, exhibit further improved 
extrusion-kneadability and film forming properties at the time of molding 
thereof. 
The second molded structures provided according to the invention are formed 
from the above-mentioned ethylene copolymer compositions, and have a 
stratiform structure similar to that of the first molded structures of the 
invention, and hence are excellent in gas barrier properties and also in 
pinhole resistance. 
EXAMPLE 
The present invention is illustrated below more in detail with reference to 
examples. In this connection, the kneading method, molding-processing 
method, evaluation and analytical method employed for the resins used in 
the examples and comparative examples were conducted by the following 
procedures under the conditions mentioned below. 
(1) MFR (melt flow rate) 
The measurement was conducted in accordance with JIS K-760. 
Temperature: 190.degree. C. or 210.degree. C. (190.degree. C. in the 
measurement of the composition) 
Load: 2160 g 
(2) Apparent melt viscosity 
Using Instron (U.S.A.) capillary rheometer 3211, the shearing stress was 
detected at a melting temperature and shearing rate as prescribed to 
calculate an apparent melt viscosity therefrom. Particulars of this 
measurement are as follows: 
Specification of the capillary rheometer 3211 
Plunger speed . . . 0.06-20 cm/min 
Load capacity . . . 500-2000 kg 
Test temperature . . . 40.degree.-399.degree. C. 
Temperature control . . . .+-.2.degree. C. at barrel portion. 
.+-.0.5.degree. C. at capillary portion. 
Barrel . . . Diameter 0.953.+-.0.0013 cm. Effective length 25 cm. 
(Including capillary portion) 
Capillary . . . Diameter 0.0762 cm. Length 2.54 cm. Material Tungsten 
carbide 
Entrance angle . . . 90.degree.. 
(3) Method for kneading resin 
The resins were melt kneaded in the prescribed proportion under the 
following conditions. 
Kneader . . . Single screw extruder, 30 mm.phi. 
Screw . . . Plunger head type single flight screw L/D=33 
______________________________________ 
Barrel Temperature (.degree.C.) 
______________________________________ 
C 1 C 2 C 3 C 4 C 5 D 
80 150 180 200 200 180 
______________________________________ 
Screw speed . . . 40 rpm 
(4) Extrusion kneadability 
The extrusion kneadability was judged by visual observation of the state of 
strand of the molten resin extruded through the die at the time of 
kneading the resin in (3) above. 
(5) Method for forming film and evaluation of formability 
Blown films were formed by means of a blown film machine comprising a 
single screw full flight extruder of 30 mm.phi. under the following 
conditions. 
______________________________________ 
C 1 C 2 C 3 C 4 H D 
150 200 200 200 200 200 
______________________________________ 
Examples 1, 3-7, 9-18 
Examples 2, 8 
______________________________________ 
Screw speed 45 rpm 60 rpm 
Haul-off speed 3 m/min 4 m/min 
Film thickness 50 .mu.m 50 .mu.m 
Blow-up ratio 2.8 2.8 
______________________________________ 
The film formability was judged by observation of the stable state of 
bubbles at the time of molding the blown films. 
In Examples 2 and 8, the films were formed by changing the discharging rate 
of the molten resin from the extruder. 
In this connection, the above-mentioned molding conditions are those 
employed in ordinary blown film forming method, and no particular 
procedure such as control of dispersion or flowing state of the 
ethylene/vinyl alcohol resin. 
(6) Measurement of the amount of oxygen gas permeated 
Using a gas permeability tester (differential pressure method) manufactured 
and sold by Toyo Seiki K.K., the amount of oxygen gas permeated through a 
film of 50 .mu.m in thickness obtained by the method shown in the (5) 
above in an atmosphere of 23.degree. C..times.50% RH was measured. 
The resins used in the examples and comparative examples are shown in Table 
1. 
TABLE 1 
__________________________________________________________________________ 
Apparent melt 
MFR [dg/min] 
viscosity 
190.degree. C. 
210.degree. C. 
[Pa .multidot. S] 
Classification 
Name Composition 
2160 g 
2160 g 
(220.degree. C., 100 
__________________________________________________________________________ 
sec.sup.-1) 
[A] (1) Evaflex 
Ethylene/ 
VA content 
2.5 452 
Ethylene 
EV460.sup.1) 
vinyl 19 wt % 
polymer 
(2) Evaflex 
acetate 
VA content 
3.5 368 
EV560.sup.1) 
copolymer 
14 we % 
(3) Evaflex VA content 
15 112 
EV450.sup.1) 19 wt % 
(4) Evaflex VA content 
1 592 
EV170.sup.1) 33 wt % 
(5) Evaflex VA content 
2 487 
EV360.sup.1) 25 wt % 
##STR1## VA content 19 wt % 
10 191 
(7) Evaflex VA content 
1 586 
EV270.sup.1) 28 wt % 
(8) Mirason VA content 
23 98 
PO607.sup.2) 6 wt % 
(9) Mirason 
Ethylen 
VA content 
3.7 390 
M-16.sup.2) 
polymer 
0 wt % 
(10) Toughmer 
Ethylene/ 
Butene 3.5 372 
A4085.sup.2) 
1-butene 
content 
copolymer 
15 mol % 
[B] (1) Sealer OH.sup.3) 4416 
VOH content 16 4 
Ethylene/ 56 mol % 
vinyl (2) Sealer OH.sup.3) 3007 
VOH content 7 6 
alcohol 70 mol % 
copolymer 
(3) Sealer OH.sup.3) 3003 
VOH content 3 15 
70 mol % 
[C] (1) Ethylene/1-butene 
Butene content 
2.3 659 
Ethylene 
copolymer 15 mol % 
copolymer 
MAH modified product 
MAH content 
graft- 1 wt % 
modified 
(2) Ethylene/vinyl 
VA content 
6.0 298 
product 
acetate copolymer 
19 wt % 
MAH modified product 
MAH content 
1 wt % 
__________________________________________________________________________ 
.sup.1) Product of Du PontMitsui Polychemicals Co., Ltd. 
.sup.2) Product of Mitsui Petrochemical Industries, Ltd. 
VA: vinyl acetate 
.sup.3) Product of Du Pont 
VOH: Vinyl alcohol 
MAH: Maleic anhydride 
EXAMPLES 1-6 
The ethylene/vinyl acetate copolymer (A) and the ethylene/vinyl alcohol 
copolymer (B) shown in Table 1 were kneaded in the proportion as indicated 
in Table 2 by the method as described in the aforementioned (3) to prepare 
an ethylene copolymer composition. MFR of the ethylene copolymer 
composition thus obtained and the amount of oxygen permeated through a 
film obtained from said composition were measured. 
Results obtained are shown in Table 2. 
A photograph of the section of the film of Example 1 taken by electron 
microscope is shown in FIG. 1. 
COMATIVE EXAMPLES 1-6 
The ethylene copolymer (A) and the ethylene/vinyl alcohol copolymer (B) 
shown in Table 1 were kneaded in the proportion as indicated in Table 3 by 
the method as described in the aforementioned (3) to prepare an ethylene 
copolymer composition. MFR of the ethylene copolymer composition thus 
obtained and the amount of oxygen permeated through a film obtained from 
said composition were measured. 
Results obtained are shown in Table 3. 
TABLE 2 
__________________________________________________________________________ 
Difference in 
Amount of 
Ethylene 
Screw speed 
apparent melt 
oxygen 
copolymer 
at the time 
viscosity permeated 
composition 
of molding 
MFR A-B [Pa .multidot. S] 
50 .mu.m 
Example 
(wt %) film rpm 
dg/min 
(220.degree. C., 100 sec.sup.-1) 
cm.sup.3 /m.sup.2 .multidot. 24 hr 
.multidot. atm 
__________________________________________________________________________ 
1 A-(1)/B-(1) = 
45 3.6 448 8.6 
60/40 
2 A-(1)/B-(1) = 
60 3.6 448 10.0 
60/40 
3 A-(1)/B-(1) = 
45 3.3 448 54.0 
70/30 
4 A-(1)/B-(2) = 
45 2.1 446 22.0 
70/30 
5 A-(4)/B-(1) = 
45 2.8 558 6.8 
60/40 
6 A-(5)/B-(1) = 
45 3.2 483 9.4 
60/40 
__________________________________________________________________________ 
TABLE 3 
__________________________________________________________________________ 
Difference in 
Amount of 
Ethylene 
Screw speed 
apparent melt 
oxygen 
copolymer 
at the time 
viscosity permeated 
Comp. 
composition 
of molding 
MFR A-B [Pa .multidot. S] 
50 .mu.m 
Example 
(wt %) film rpm 
dg/min 
(220.degree. C., 100 sec.sup.-1) 
cm.sup.3 /m.sup.2 .multidot. 24 hr 
.multidot. atm 
__________________________________________________________________________ 
1 A-(2)/B-(1) = 
45 4.4 364 1300 
70/30 
2 A-(3)/B-(3) = 
45 12.3 
97 7560 
60/40 
3 A-(9)/B-(1) = 
45 4.2 386 2330 
70/30 
4 A-(6)/B-(1) = 
45 10.9 
176 896 
60/40 
5 A-(1) 45 2.5 -- 7550 
6 A-(3) 45 15 -- 7930 
__________________________________________________________________________ 
EXAMPLES 7-18 
The three components, i.e. the ethylene/vinyl acetate copolymer (A), 
ethylene/vinyl alcohol copolymer (B) and ethylene/.alpha.-olefin copolymer 
graft-molded product (C) shown in Table 1 were kneaded in the proportions 
as indicated in Table 4 by the method as described in the aforementioned 
(3) to prepare an ethylene copolymer composition. The performance of the 
resulted composition and the molded structure obtained therefrom, such as 
extrusion kneadability, film-forming properties and the amount of oxygen 
permeated through the blown film, was evaluated. 
Results obtained are shown in Table 4. 
TABLE 4 
__________________________________________________________________________ 
Difference in 
Amount of 
Ethylene apparent melt 
oxygen 
copolymer Film viscosity permeated 
composition 
Extrusion 
forming 
A-B [Pa .multidot. S] 
50 .mu.m 
Example 
(wt %) kneadability 
properties 
(220.degree. C., 100 sec.sup.-1) 
cm.sup.3 /m.sup.2 .multidot. 24 hr 
.multidot. atm 
__________________________________________________________________________ 
7 A-(1)/B-(1)/ 
good .largecircle. 
448 20 
C-(1) 
42/40/18 
8 A-(1)/B-(1)/ 
good .largecircle. 
448 22 
C-(1) 
42/40/18 
9 A-(1)/B-(1)/ 
good .largecircle. 
448 97 
C-(1) 
63/30/7 
10 A-(1)/B-(1)/ 
good .largecircle. 
448 15 
C-(1) 
50/40/10 
11 A-(1)/B-(1)/ 
good .DELTA. 
448 152 
C-(1) 
35/30/35 
12 A-(1)/B-(1)/ 
good .largecircle. 
448 42 
C-(1) 
55/30/15 
13 A-(4)/B-(1)/ 
good .largecircle. 
588 10 
C-(1) 
50/40/10 
14 A-(4)/B-(2)/ 
good .largecircle. 
588 18 
C-(1) 
50/40/10 
15 A-(4)/B-(3)/ 
good .largecircle. 
577 78 
C-(1) 
50/40/10 
16 A-(5)/B-(1)/ 
good .largecircle. 
483 8 
C-(1) 
50/40/10 
17 A-(7)/B-(2)/ 
good .largecircle. 
580 21 
C-(1) 
50/40/10 
18 A-(7)/B-(3)/ 
good .largecircle. 
571 73 
C-(1) 
50/40/10 
__________________________________________________________________________ 
*.largecircle.: good .DELTA.: unstable X: failed in film forming 
COMATIVE EXAMPLES 7-13 
The three components, i.e. the ethylene/vinyl acetate copolymer (A), 
ethylene/vinyl alcohol polymer (B) and the ethylene/.alpha.-olefin 
copolymer graft-modified product (C) shown in Table 1 were kneaded in the 
proportions as indicated in Table 5 by the method as described in the 
aforementioned (3) to prepare an ethylene copolymer composition. The 
performance of the resulted composition and the molded structure obtained 
therefrom, such as extrusion kneadability, film forming properties and the 
amount of oxygen permeated through the blown film, was evaluated. 
Results obtained are shown in Table 5. 
TABLE 5 
__________________________________________________________________________ 
Difference in 
Amount of 
Ethylene apparent melt 
oxygen 
copolymer Film viscosity permeated 
Comp. 
composition 
Extrusion 
forming 
A-B [Pa .multidot. S] 
50 .mu.m 
Example 
(wt %) kneadability 
properties 
(220.degree. C., 100 sec.sup.-1) 
cm.sup.3 /m.sup.2 .multidot. 24 hr 
.multidot. atm 
__________________________________________________________________________ 
7 A-(1)/B-(1)/ 
Melt X 448 264 
C-(1) fracture 
20/30/50 
8 A-(1)/B-(1)/ 
good .DELTA. 
448 3260 
C-(2) 
42/40/18 
9 A-(8)/B-(1)/ 
good .largecircle. 
94 2013 
C-(1) 
50/30/20 
10 A-(9)/B-(1)/ 
good .largecircle. 
386 2020 
C-(1) 
63/30/7 
11 A-(9)/B-(1)/ 
good .DELTA. 
386 2080 
C-(2) 
63/30/7 
12 A-(10)/ good .DELTA. 
368 6340 
B-(1)/C-(1) 
49/30/21 
13 A-(3)/B-(1)/ 
good .largecircle. 
108 7330 
C-(2) 
50/40/10 
__________________________________________________________________________ 
*.largecircle.: good .DELTA.: unstable X: failed in film forming