JP3357156B2 - Method for producing molded article having gradient layered distribution structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates, basically ethylene -
Vinyl alcohol copolymer (A) and heats other than (A)
Material layer film of the plastic resin (B), relates to a process for producing a molded article having a layered distribution structure inclined viewed in cross-sectional thickness direction of the molded body such as Chiyubu, especially hydrophobic as the thermoplastic resin (B) The present invention relates to a method for industrially easy production of a molded article for the purpose of improving the adhesiveness of both resins, improving gas barrier properties, and improving fragrance retention when a thermoplastic resin is used.

[0002]

2. Description of the Related Art Ethylene-vinyl alcohol copolymer (hereinafter abbreviated as EVOH) is a thermoplastic resin having excellent gas barrier properties, fragrance retention properties and oil resistance. When exposed to water or in contact with polar solvents such as water and alcohol, the above properties are lost. Therefore, a laminated molded article comprising at least two layers of EVOH and a hydrophobic thermoplastic resin or more is desired. However, the biggest problem in laminating the EVOH and the hydrophobic thermoplastic resin is that the adhesiveness of the interface between the EVOH and the hydrophobic thermoplastic resin is insufficient.
In many cases, it is not practically usable because of easy peeling.

As a countermeasure, a method is generally used in which an adhesive resin obtained by adding maleic anhydride to a thermoplastic resin or the like is sandwiched between an EVOH and a thermoplastic resin to increase the adhesion between the two. In addition, the adhesiveness is not always perfect, and especially when the multilayer structure is deformed below the melting point of the resin such as a stretching operation, the adhesiveness is remarkably reduced and it is not practical. Often not. A further major problem is that no suitable adhesive resin is found for some thermoplastic resins.

On the other hand, as a method not using an adhesive resin, as disclosed in JP-A-48-75645, a thermoplastic resin is added to EVOH in an amount of 1 to 30% by weight to adhere to the thermoplastic resin. EVOH is added to a thermoplastic resin in an amount of 1 to 30% by weight,
Although there are published methods to improve the adhesion with
As shown in the publication, the molding conditions (temperature,
It is very difficult to stably distribute the concentration distribution in the direction of the inner surface of the layer as desired by speed or the like. As a result, not only is the adhesiveness insufficient, but also the commercial value is reduced due to opacity. It is not preferable in terms of quality.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a layered distribution structure in which EVOH and other hydrophobic thermoplastic resins are inclined in the cross-sectional thickness direction of a molded product such as a film or a tube. It is an object of the present invention to provide a method for industrially easily producing a surface-modified molded product having (having a concentration gradient), strong adhesion, high gas barrier properties, and excellent fragrance retention. is there.

[0006]

The above object is at least achieved by the following.
Manufacture of a molded article comprising EVOH (A) and a thermoplastic resin (B) other than (A), and having a cross-sectional structure in the thickness direction having a gradient layered distribution structure having a concentration gradient of (A) and (B). In the method, (A) and (B) are each melted,
When the melt of (A) and the melt of (B) are viewed from a cross section perpendicular to the flow direction when they are merged from the left and right, an inclined interface in which the contact interface between them is inclined to the left and right A step of forming a left-right two-layer flow having a laminar flow, a step of kneading the two-layer flow by applying a shearing action from above and below, and introducing the fluid into a molding machine such that the up and down direction is the width direction of the obtained molded body And a step of extruding the introduced fluid from a molding machine in the above-described order. Furthermore, the above-mentioned object is to provide at least EVOH (A) and a thermoplastic resin other than (A).
Becomes because the RESIN (B), the thickness direction of the sectional structure,
In the method for producing a molded article having a gradient layered distribution structure having a concentration gradient of (A) and (B), (A) and (B) are respectively melted, and a melt of (A) and a melt of (B) are melted. A step of creating a left-right two-layer flow having an inclined interface in which the contact interface between the two is inclined left and right, as viewed in a cross section perpendicular to the flow direction when the two are merged from the left and right. A step of thinly stretching the two-layer flow to the left and right, a step of kneading the stretched two-layer flow by applying a shearing action from above and below, a step of compressing the kneaded fluid in the left-right direction, the compressed fluid,
A step of introducing the introduced fluid into the molding machine so that the vertical direction thereof corresponds to the width direction of the obtained molded body, and a step of extruding the introduced fluid from the molding machine in the above-described order. Achieved by:

In the manufacturing method of the present invention, at least
EVOH (A) and thermoplastic resin other than (A) (B)
An important point is a method of forming a layered distribution structure in which the two types of material layers composed of are inclined when viewed in the cross-sectional thickness direction of the molded body. FIG. 1 is a conceptual diagram of an example of the present invention for explaining the process.

In FIG. 1, EVOH (A) and a thermoplastic resin other than (A) are basically used as the first step of the present invention.
The meltable resin (B) is melted, and the melt of (A) and the melt of (B) are viewed in a cross section perpendicular to the flow direction when the two are merged from the left and right, as shown in the figure. As described above, it is important to form a left and right two-layer flow having an inclined interface in which the contact interface of both the right and left is inclined to the left and right. It is the basis of the body. The premise in this step is that under the condition that the melt viscosities of (A) and (B) are almost equal, the two-layer flow of the melted (A) and (B) will not be subjected to forced mixing unless forced mixing is performed. This is based on the fact that the state of the merged state is almost maintained, and the cross-sectional shape of the cross-sectional form is maintained as a so-called Kintaro candy type having a bilaterally inclined interface.

As a second step, a process of stretching the right and left two-layer flow having the inclined interface in the right and left X directions as viewed in a cross section perpendicular to the flow direction and in the flow direction (Z direction in the drawing). It is important to take This is a step that can be called a preliminary step for causing the two-layer flow to sufficiently knead the X-direction and the Z-direction in the next step. Can be obtained by gradually narrowing the interval in the vertical Y direction and gradually increasing the interval in the horizontal X direction.

In the kneading of the two-layer flow in the X and Z directions in the third step following the second step, for example, as shown in FIG. This can be done by rotating. In FIG.
Various modifications of the flow path and the cylindrical rotating body are shown. In any case, the kneading and shearing action in the X and Z directions of the two-layer flow can be sufficiently provided. It is important to make the gap with the rotating body narrow. By this kneading, thermoplastics other than EVOH (A) and (A)
The two-layer flow composed of the conductive resin (B) makes the two adhere more firmly to each other, and it is possible to further reduce the separation between substances in the resulting molded article.

The fourth step is a step in which the kneading fluid is compressed in the direction opposite to the direction in which the kneading fluid was elongated in the second step, and is restored to a shape close to the first step. In the process so far,
Although the contact interface between (A) and (B) is a two-layer flow that is more firmly bonded, this two-layer flow is tentatively introduced as it is into a die for forming a film, tube, or the like.
If a molded article such as the film or tube is molded, the film layer and the tube layer of the molded article are viewed in a cross section thereof.
(A) and (B) do not overlap, but simply form a "layer structure in a state where they are arranged side by side" alone. Therefore, the original purpose of improving the characteristics by performing the process cannot be achieved. Therefore, in order to obtain a layer structure in which (A) and (B) are always in a multilayer structure in the vertical direction with respect to the cross section of the molded body layer, the left and right two-layer flow is directly applied to the die. Instead of guiding, it is necessary to convert the left-right direction to the up-down direction and guide it into the dice. This step is a preliminary step in the next step for performing this conversion and introducing the two-layer flow into the die. In this step, in order to compress the two-layer flow expanded in the left-right direction from the width direction and to cause re-convergence (shrinkage) in the width direction, the flow path in the second step should be reversed. It can be done by introducing.

In the fifth step, re-convergence in the width direction is performed in the above step, so that the compressed fluid obtained as the left and right two-layer flow of (A) and (B) in the first step is subjected to the left and right two-layer flow. Is introduced into a flow path twisted by 90 ± 20 degrees, preferably 90 ± 10 degrees so that a two-layer flow is formed in the upper and lower directions. A compressed fluid with this axis twisted is formed into a film, tube or the like. In this step, when the fluid is extruded from the die in the next sixth step, (A) and (A) are obtained in the cross section of the obtained molded body layer as described above. A molded article having a layered structure in which (B) is always in a multilayer state in the vertical direction with respect to each other can be obtained.

In the above-described manufacturing method described with reference to FIG. 1, for convenience of explanation, in the first step, two types of melts (A) and (B) are merged "from right and left" in the drawing. The description will be made on the assumption that the flow is treated as the "left and right" two-layer flow, and the steps will be described on the premise of this. However, in the production method of the present invention, (A) and (B) It is essential to create a two-layer flow, but it is not essential to merge "from left and right" into a "left and right" two-layer flow. That is, the same applies to the case where the "up and down" two-layer flow is formed instead of the "left and right" two-layer flow in the first step of FIG. 1 and the subsequent steps are advanced. In this case, the result obtained in the fourth step is obtained. In the fifth step, the compressed two-layer flow does not necessarily need to be twisted by 90 ± 20 degrees about the axis in the flow direction, and may be introduced directly into a die or the like. That is, in the description of the present specification, “left and right” or “up and down” is for the convenience of explanation using the drawings, and the “right and left” or “left and right” is used without departing from the technical spirit of the present invention. Or "up and down".

The most important step in the present manufacturing method is the kneading step in the third step. That is, if a layer structure in which the layers (A) and (B) are simply arranged in contact with each other in a side-by-side state is adopted, the adhesion at the layer interface is reduced due to the peeling at the layer interface, and the impact at the layer interface due to impact or the like. Void whitening is more likely to occur, so it is an important technical development requirement how to increase the contact surface at the layer interface and reduce the occurrence of the peeling. In the present manufacturing method, as described above, a cylindrical rotary kneader in which a two-layer flow in which two substances are merged so as to have an inclined interface in the first step is set in the X direction in the kneading step in the third step And further strengthen the adhesion between the two substances at the inclined contact interface.
It is also important to combine the layers (A) and (B) in the thickness direction in the film layer, tube layer or the like in the obtained molded article by the fourth to fifth steps. The point is to create a multilayered film,
The tube or the like has a layer structure in which the thickness is multiplied in principle in the thickness direction, and the above-mentioned decrease in the adhesive strength and opacity are suppressed.

[0015] The ethylene content of the EVOH (A) used in the present invention is selected from the range of 10 to 70 mol%, preferably 15 to 65 mol%. If the ethylene content is less than 10 mol%, the melt moldability is poor, while if it is 70 mol% or more, the gas barrier properties are insufficient. The saponification degree of EVOH is 9
If it is 0% or more, preferably 95% or more, and if it is less than 90%, gas barrier properties and thermal stability will be poor.

In the present invention, vinyl acetate is a typical example of the vinyl ester used in the production of EVOH, but other comonomer such as propylene may be used as long as the object of the present invention is not impaired. , Butylene, unsaturated carboxylic acid or its ester {(meth) acrylic acid, (meth) acrylate methyl, ethyl), etc.}, vinylpyrrolidone (N-vinylpyrrolidone, etc.), vinylsilane compound, etc. It is possible to blend a heat stabilizer, an ultraviolet absorber, an antioxidant, a colorant, and other resins (polyamide, partially saponified ethylene-vinyl acetate copolymer, etc.). Further, a preferable EVOH used in the present invention is a melt viscosity index (melt index; MI).
(Value measured under a load of 2160 g at 190 ° C .:
Those whose melting point is around 190 ° C or higher than 190 ° C
It was measured at a plurality of temperatures above the melting point under a load of 160 g, and plotted with the reciprocal of the absolute temperature on the horizontal axis and the melt index on the semi-logarithmic graph as the vertical axis, and extrapolated to 190 ° C.). 1 to 50 g / 10 min. , Optimally 0.5 to 20 g / 10 min. belongs to.

The thermoplastic resin (B) used in the present invention is not particularly limited, and examples thereof include polyethylene, polypropylene, polyamide, polyester,
Polycarbonate, polyacrylonitrile, polyacrylate, polymethacrylate, polystyrene, ethylene-vinyl ester copolymer, ethylene-
Acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylic ester copolymer, ethylene-methacrylic ester copolymer, polyvinyl chloride,
Examples thereof include polyvinylidene chloride, polyvinyl fluoride, and silicone resin. The mixing ratio of (A) and (B)
(A) :( B) = 5: 95 to 95: 5 is preferred, and more preferably 10:90 to 90:10.

Here, as a more preferable condition of the characteristics of the thermoplastic resin (B), MI at the molding temperature is similar to that of the EVOH (A). The ratio is in the range of 50 to 1/50, more preferably 20 to 1/20, and still more preferably 10 to 1/10. If the ratio is more than 50 to 1/50, uniform fine dispersion cannot be performed, and appearance defects such as opacity tend to occur.

In order to improve the compatibility between (A) and (B), a compatibilizer may be added in an amount of 0.5 to 20% by weight. As the compatibilizer, for example, a modified resin similar to the thermoplastic resin (B) having a functional group capable of reacting or interacting with EVOH, such as maleic anhydride, carboxylic acid, and silyl compound, is effective.

When blending, other additives (plasticizers, heat stabilizers, ultraviolet absorbers, antioxidants, coloring agents, fillers, other resins, etc.) are used within a range that does not impair the object of the present invention. You are free to do it. In particular, as a measure for preventing gel formation, a hydrotalcite-based compound, a hindered phenol-based, a hindered amine-based heat stabilizer, a metal salt of a higher aliphatic carboxylic acid (for example, calcium stearate, magnesium stearate, or the like), or It is preferable to add two or more of them in an amount of 0.01 to 1% by weight.

The EVOH (A) of the present invention and other than (A)
The thickness of the graded structure layer (C) having a graded multilayered distribution structure with the thermoplastic resin (B) is 0.1 to 10
00μ, preferably 1-100μ, more preferably 1-50
μ. The concentration distribution of (A) in the thickness direction of the gradient layer distribution structure layer (hereinafter sometimes simply referred to as the gradient structure layer) (C) is not particularly limited, but generally, the concentration distribution in the thickness direction of the molded body is not limited. One end has a structure in which the concentration of (A) is high, the concentration of (A) decreases as going to the other end, and an intermediate gradient structure layer in which the concentration of (B) increases. As the molded article intended in the present invention, a molded article having a structure in which the intermediate inclined structure layer is positioned about 10 to 90% inside the entire thickness of the inclined structure layer (C) is preferable.

Incidentally, the structure of the gradient structure layer (C) is as follows: surface layer of (A) / intermediate gradient structure layer of AB
(B) surface layer, (A) surface layer / AB intermediate gradient structure layer / BA intermediate gradient structure layer / (A) surface layer, (B) surface layer / BA intermediate gradient structure layer / AB middle gradient structure layer / (B) surface layer, (A) surface layer / AB middle gradient structure layer / (B) middle layer / BA middle gradient structure layer / (A)
Surface layer of (B) / intermediate graded structure layer of BA /
(A) intermediate layer / AB intermediate gradient structure layer / (B) surface layer, or (B) surface layer / BA intermediate gradient structure layer /
(A) Intermediate layer / (B) ′-A Intermediate graded structure layer /
The configuration of the surface layer of (B) ′ and the like can be mentioned, and these various configurations can be easily realized by a slight change of the molten resin introduction portion in the first step in the manufacturing method. FIG. 2 is a cross-sectional view of a polymer flow at an introduction portion showing an example of a combination configuration of the polymers. In addition, the intermediate gradient structure layer AB refers to a layer configuration in which the concentration of A is high, the concentration of A gradually decreases, and the concentration of B is high. , B concentration is high, the B concentration gradually decreases, and the A concentration increases. Further, the and (B) ', of the thermoplastic resin (B), shall refer to it in order to use (B) and not the same type thermoplastic resin.

The structure comprising the above-mentioned inclined structure layer (C) can be formed into an arbitrary molded product such as a film, a sheet, a bottle, etc. by a well-known melt molding method or compression molding method. Not only is it molded as a single layer of C), but also other layers such as the (A) layer, (B) layer,
Extrusion lamination, dry lamination, co-extrusion lamination, co-extrusion sheet molding, co-extrusion pipe molding, co-injection with or without a resin layer consisting of (B) ′ and an adhesive resin A method of forming a multilayer structure by a molding method, a solution coating method, and the like, and then performing a stretching operation by reheating the multilayer body to a temperature equal to or lower than the melting point of EVOH by vacuum pressure deep drawing, stretch blow molding, or the like, or By subjecting the multilayer body (film or sheet) to a biaxial stretching machine and performing a method of heating and stretching, other characteristics can be further reinforced.

The thickness structure of the multilayer structure is not particularly limited. However, when the formability and cost are taken into consideration, the EV relative to the total thickness is
The thickness ratio of the (A) layer such as the OH layer is suitably from 2 to 20%. In addition, as a configuration of the multilayer structure, a gradient structure layer (C) / (A) layer, a gradient structure layer (C) / (B) layer, a gradient structure layer (C) / adhesive resin (E) layer / ( B) 'layer,
(A) layer / graded structure layer (C) / (B) layer, (B) ′ layer /
Adhesive resin (E) layer / (A) layer / graded structure layer (C) /
(B) layer, (B) 'layer / collection layer / adhesive resin (E) layer /
(A) layer / gradient structure layer (C) / (B) layer is mentioned as a typical one. When a thermoplastic resin layer is provided on both outer layers, the resins may be different or may be the same. In many cases, scrap such as trim generated during molding is blended into the thermoplastic resin layer, or a separate recovery layer is provided for reuse.

The thus obtained inclined structure layer (C)
(A) and (B) which do not have a good adhesive resin, for example, EVOH (A) and various thermoplastic resins (B) are firmly adhered to each other as an initial purpose, A molded body without void whitening can be obtained. Further, in the present invention, an inorganic substance in the (A) or (B) layer,
By blending a metal, a gradient structure layer having a difference in the concentration of an inorganic substance and a metal can be obtained, and the gas barrier properties can be further improved. Hereinafter, the present invention will be further described with reference to Examples, but the present invention is not limited thereto.

[0026]

【Example】

Example 1 Ethylene content 44 mol%, degree of saponification 99.6%, melt index (MI 190 ° C., 2160 g load) 5.5
g / 10 min. EVOH (A) and a thermoplastic resin (B) obtained by blending 20 parts by weight of a vinylmethoxysilane-modified polypropylene resin with 100 parts by weight of a polypropylene resin having an MI of 5.0, and these two resins are each heated and melted. As shown in FIG. 1, the melt was introduced into a regulated introduction path and merged so that the contact interface between them became a two-layer flow having an interface inclined left and right (first step). Next, this two-layer flow is introduced from the introduction path into a flow path that widens the left-right space in a divergent manner and at the same time narrows the vertical space (second step). The kneaded molten fluid is then guided to the shearing roller section 3 and kneaded (third step). The kneaded molten fluid is then narrowed in a tapered manner in the reverse positional relationship with the divergent flow path, and at the same time, The flow was led to a flow path that widened the vertical interval, and was again formed into a two-layer flow shape in the first step having an inclined interface (fourth step). The flow path is then twisted 90 degrees clockwise about its flow direction, so that the two-layer flow is twisted 90 degrees (fifth step) and introduced into the extruder in this twisted state. (Sixth step) to obtain a multilayer film of EVOH (A) layer / intermediate gradient structure layer of AB / polypropylene resin (B) layer.

The film was immersed in hot xylene (130 ° C.) to slightly dissolve the polypropylene, the cross section was observed with an electron microscope, the cross-sectional area of EVOH was measured, and the EVOH concentration was calculated. As a result, the EVOH concentration was 100% from 0 to 12 μm, 70% from 12 to 14 μm, and 14 to 16 μm.
45% up to μ, 15% up to 16-18μ, 18%
It is 0% (polypropylene 100%) up to μ20 μm, and it is confirmed that the film has an inclined structure of EVOH (A), and thus also polypropylene resin (B), in the thickness direction of the film.

An attempt was made to evaluate the adhesiveness of the obtained multilayer film including the inclined structure layer, but each layer could not be peeled off and showed such a strong adhesion that it could not be measured. The multilayer film was biaxially stretched at 150 ° C. 3 × 3 times. The transparency of the obtained film was good, and the adhesiveness was so strong as to be unstretched that it could not be peeled off and could not be measured.

COMPARATIVE EXAMPLE 1 In Example 1, a simple left-right two-layer flow was produced in the first step, this was led to the fifth step by omitting the second to fourth steps, and then introduced into a co-extrusion apparatus, and the EVOH was introduced.
A multilayer film of (A) layer / polypropylene resin layer (B) was obtained. The multilayer film hardly adheres, and the adhesive strength at a take-off speed of 250 mm / min is 15 g / 15 m.
m width and a very low value.

Comparative Example 2 In Example 1, the second to fourth steps were not carried out, and the mixture was led to a co-extrusion apparatus, and an EVOH (A) layer / adhesive resin (maleic anhydride-modified polypropylene resin) / polypropylene resin layer (B) Was obtained. The adhesive strength of the multilayer film showed a relatively high value of 600 g / 15 mm width. However, as in Example 1, the adhesive strength of the biaxially stretched film was as large as 35 g / 15 mm in width, and the adhesive strength was greatly reduced.

Example 2 Ethylene content: 44 mol%, saponification degree: 99.6%, mel
4. Index (MI 190 ° C, 2160g load) 5.
5 g / 10 min. EVOH (A) and EVOH
(A) 30 parts by weight of ultrafine titanium oxide (average particle diameter)
0.1μ or less) Resin (B) blended with 70 parts by weight
And the same steps as in Example 1 were performed.
μEVOH monolayer film was obtained. The cross section of the film
Observation was made with an electron microscope, and the titanium oxide concentration was calculated. That
As a result, from 0 to 10 μm, the titanium oxide concentration was 0% (EVOH
(Concentration 100%), up to 10-12μ, 20%, 12-
55% up to 14μ, 35% up to 14-16μ,
10% up to 16-18μ, up to 18-20μ
Shows a gradient structure of 0% (EVOH concentration 100%)
I confirmed that The film is kept at 20 ° C-100% RH
For 5 days, and measured gas barrier properties (Mocon
5cc. 20μ / m ^Two. 2
4 hr. Atm and good gas barrier properties were exhibited. Also
Tensile breaking strength (autograph, 500 mm / min.)
Is 6 kg / mm2, and the elongation at break is relatively good at 120%.
The value was shown.

Comparative Example 3 Using the EVOHs (A) and (B) used in Example 2,
As in Comparative Example 1, a simple three-layer flow is produced in the first step, the second to fourth steps are omitted, the process is led to the fifth step, and then introduced into the co-extrusion apparatus, where the EVOH (A) / (EV) / (B) / E
An attempt was made to obtain a multilayer film of VOH (A). However, the occurrence of uneven flow was remarkable, and not only a good film could not be obtained, but also the resin (B) layer was very brittle, and external forces such as bending and pulling were observed. Causes peeling in the layer, resulting in poor appearance and resin (B) / E
Adhesion failure between VOH (A) occurs, and it is not a material that can withstand use at all.

Example 3 The polypropylene resins (A) and (B) used in Example 2 and the polypropylene resin having an MI of 5.0 used in Example 1 were used.
Thermoplastic resin (B) 'blended with 20 parts by weight of vinylmethoxysilane-modified polypropylene resin per 0 parts by weight
The first to fifth steps were carried out in the same manner as in Example 1 and introduced into an extruder using the above three to obtain a multilayer film of EVOH (A) layer / intermediate gradient structure layer / polypropylene resin layer (B) ′. . The film was immersed in hot xylene (130 ° C.) to slightly dissolve the polypropylene, and the cross section of the film was subjected to electron microscope to calculate the EVOH concentration and the titanium concentration from the area of the EVOH. 0%, EVOH 80% up to 10-12μ, titanium oxide 20%, EVOH 45% up to 12-14μ,
55% titanium oxide, EVOH21 up to 14-16μ
%, 49% titanium oxide, 30% polypropylene, 16 ~
EVOH 12%, titanium oxide 28%, polypropylene 60% up to 18μ, EVOH 0% up to 18-20μ,
It was 0% titanium oxide and 100% polypropylene, indicating a graded structure.

[0034]

According to the present invention, EVOH (A) and (A)
The other thermoplastic resin (B) is exposed on one side of a molded product, for example, a film, and the internal composition of the film is changed from the exposed surface of the thermoplastic material (B) to the other surface {(A) surface}. (A) is a method for producing a molded article having a gradient structure layer having a concentration gradient in which the concentration of (A) gradually increases.
It is possible to obtain the molded article (B) which is firmly bonded.

[Brief description of the drawings]

FIG. 1 is a manufacturing conceptual diagram for explaining a manufacturing process of the present invention.

FIG. 2 is a cross-sectional view of a polymer flow in a first step showing a combination configuration of polymers in the present invention.

3 (a) to 3 (d) are schematic cross-sectional views of a third step illustrating various modes of a shearing and kneading step in the third step of the present invention.

[Explanation of symbols]

 Reference Signs List 1 die 2 film 3 inclined structure layer 4 middle inclined structure layer M motor

Claims (3)

(57) [Claims] 1. A composition comprising an ethylene-vinyl alcohol copolymer (A) and a thermoplastic resin (B) other than (A), and having a cross-sectional structure in the thickness direction having a concentration of (A) and (B). In a method for producing a molded body having a gradient layered distribution structure having a gradient, (A) and (B) are each melted,
When the melt of (A) and the melt of (B) are viewed from a cross section perpendicular to the flow direction when the melts are merged from the left and right, the contact interface between the left and right is an interface inclined to the left and right. Forming a left-right two-layer flow having an interface, kneading the two-layer flow by applying a shearing action from above and below, and forming the fluid so that the up and down direction is the width direction of the obtained molded body. And a step of extruding the introduced fluid from a molding machine in the above order. 2. A composition comprising an ethylene-vinyl alcohol copolymer (A) and a thermoplastic resin (B) other than (A), and having a cross-sectional structure in the thickness direction having a concentration of (A) and (B). In a method for producing a molded body having a gradient layered distribution structure having a gradient, (A) and (B) are each melted,
When the melt of (A) and the melt of (B) are viewed from a cross section perpendicular to the flow direction when the melts are merged from the left and right, the contact interface between the left and right is an interface inclined to the left and right. A step of forming a left-right two-layer flow having an interface, a step of thinly stretching the left-right two-layer flow to the left and right, a step of kneading the stretched two-layer flow by applying a shearing action from above and below, and mixing the kneaded fluid in the left-right direction. In the order described above, a step of introducing the compressed fluid into a molding machine such that the vertical direction thereof is the width direction of the obtained molded body, and a step of extruding the introduced fluid from the molding machine. A method for producing a molded article having a graded layered distribution structure. 3. The thermoplastic resin (B) is polyethylene,
Polypropylene, polyamide, polyester, polycarbonate
Bonate, polyacrylonitrile, polyacrylate, polymethacrylate, polystyrene, ethylene-vinyl ester copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylic acid ester copolymer The method for producing a molded article according to claim 1, wherein the molded article is at least one selected from the group consisting of a coalesced product, an ethylene-methacrylate copolymer, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, and a silicone resin.