JPH07195510A - Vertically oriented film, sheet container and production thereof - Google Patents

Abstract

PURPOSE:To obtain a film, sheet or container made of a thermoplastic substance, especially, EVOH and a thermoplastic resin excellent in strength in its thickness direction by using at least two kinds of thermoplastic substances and orienting them vertically in a laminar state with respect to the surface of the film, sheet or container. CONSTITUTION:In a first process, molten kneaded matter 1 consisting of two or more kinds of thermoplastic substances is stretched in a lateral direction and further stretched in a flow direction and a longitudinal direction if necessary to obtain a molten kneaded material 2. In a second process, the kneaded material 2 is subjected to shearing kneading in its longitudinal direction, that is, kneaded in a rotary kneader 9 operated by a motor 10 in its longitudinal direction to obtain a molten kneaded substance 3. In a third process, the kneaded substance 3 is compressed in its lateral direction to obtain kneaded matter 4 restored into a shape near to that in the first process and distortional rotation is applied to the kneaded matter at an angle 90 deg.+ or -20 deg., pref., 90 deg.+ or -10 deg. with respect to the flow direction to obtain molten kneaded matter 5 which is, in turn, guided to a usual die 6 to be molded to obtain a single-layer or multilayer film, sheet or container oriented vertically in a larminar state with respect to the surface of the molded object.

Description

Detailed Description of the Invention

[0001]

The present invention comprises thermoplastics (A) and (B), in particular ethylene-vinyl alcohol (A) and a thermoplastic resin (B), (A) and / or (B). ) Relates to a film, sheet or container oriented in a layered manner with respect to the surface of the film, sheet or container and a method for producing the same.

[0002]

2. Description of the Related Art Ethylene-vinyl alcohol copolymer E
VOH (A) is a thermoplastic resin having excellent gas barrier properties, fragrance retaining properties, and oil resistance, but since it is hydrophilic, it is exposed to a high-humidity atmosphere or comes into contact with polar solvents such as water and alcohol as described above. Has the drawback that the properties of are lost. So E
It is generally used as a laminated molded product composed of at least two layers of VOH (A) and a thermoplastic resin or more. In this case, the pinhole resistance of the EVOH layer,
A blend composition of EVOH (A) and a thermoplastic resin (B) is used in order to improve hot water resistance (retort resistance), impact resistance, gas barrier property or scrap recovery at the time of molding a multilayer laminate. However, in order to disperse these blend compositions more uniformly, various additives have been studied, but even if the dispersion is improved, the essence of the melt molding As a characteristic property, it is oriented in a plane, linear or elliptical shape parallel to the flow direction (shear direction) of the resin, and has a concentration distribution in the depth direction with respect to the film or sheet surface. , There is a tendency that an approximately symmetrical concentration distribution is generated toward both surfaces. As a result, the various strengths of the film, sheet or container in the longitudinal and transverse directions are excellent, but there is a drawback that the various strengths of the film, sheet or container in the thickness direction are not sufficient.

[0003]

The object of the present invention is therefore to obtain thermoplastics (A) and (B), in particular EVO.
It is to obtain a film, sheet or container which is made of H (A) and a thermoplastic resin (B) and has various strengths in the thickness direction.

[0004]

The above object consists of at least two thermoplastics (A) and (B),
(A) and / or (B) is solved by providing a film, sheet or container oriented in layers in a direction perpendicular to the surface of the film, sheet or container.

A method of manufacturing the vertically aligned structure of the present invention will be described with reference to the drawings (schematic diagrams). First, FIG. 1 showing the best manufacturing method will be described. First, as a first step, two or more kinds of (A) and (B) melt-kneaded products 1 are stretched in the transverse direction and, if necessary, in the flow direction and the longitudinal direction to obtain a melt-kneaded product 2. Next, as a second step, the melt-kneaded body 2 is kneaded by applying a shearing action in the vertical direction (vertical direction), that is, a rotary kneader that rotates by a motor 10 in the vertical direction (for example, a double cylindrical rotary kneader). The mixture is kneaded with 9 to obtain a melt-kneaded body 3. Next, in a third step, the kneading body 3 is compressed from the lateral direction to obtain a kneading body 4 that has recovered to a shape close to that in the first step, and 90 ± 20 degrees, preferably 90 ± 10 degrees around the flow direction. Then, a twisted rotation is applied to obtain a melt-kneaded body 5. After that, the kneaded body 5 to which the twist rotation is applied is guided to a normal die 6 (that is, the longitudinal direction of the kneaded body becomes the horizontal direction and the horizontal direction becomes the vertical direction), and the surface of the molded product is obtained. A single-layer or multi-layer film, sheet or container 7 (cross-section in the thickness direction) oriented vertically in a layered manner (here, layered means not only layered but also planar, linear or elliptical). Structure 8) is obtained.

In FIG. 1, an important step is to apply a 90 ° ± 20 ° rotation in the third step, and by this step, (A) and / or (B) are layered perpendicularly to the surface of the film or sheet. It can be oriented. FIG. 5 shows an example {(a) to (d)} of the second step of kneading the melt-kneaded body 2 with a rotating body that rotates in the longitudinal direction. The melt-kneaded body 2 is a double cylindrical rotary kneader 9 The method of kneading is shown. The second step can be omitted, and a schematic view of the process omitting the second step is shown in FIG. In FIG. 3, 15 is a melt-kneaded product, 16
Is a melt-kneaded body after compression, and 17 is a melt-kneaded body that is twisted and rotated by 90 ± 20 degrees. Although the compression-one-shape recovery step in the third step can be omitted, it is preferable to provide it.

As another manufacturing method, there is a method in which the twisting and rotating step of the third step in FIG. 1 is omitted. A schematic diagram of this step is shown in FIG. 4. According to this method, the structure of the extruded sheet 8 is such that (A) and / or (B) is oriented perpendicularly to the sheet surface (however, it is parallel to the flow direction). Seen from the cross section). In the structure viewed from the cross section perpendicular to the flow direction, a part of (A) and / or (B) is oriented parallel to the sheet surface.

As another manufacturing method, as shown in FIG. 2, the melt-kneading body 1 is introduced into a die 6, and a rotary kneader 11 is installed in the die and is rotated by a motor 12 in a vertical direction.
There is also a method in which the sheet 13 is obtained by kneading (the same structure as 9 in FIG. 1) and then molding. According to this method, as is apparent from the cross section in the thickness direction of the extruded sheet 14 in FIG. 2, a structure in which (A) and / or (B) is oriented perpendicular to the sheet surface (however, from the cross section parallel to the flow direction) See).

The molded product thus obtained is (A)
Since (B) and (B) have a comb-like structure in which they are oriented perpendicular to the surface of the film, sheet or container, various strengths in the thickness direction are excellent.

In the present invention, as the thermoplastic substances (A) and (B), various thermoplastic resins can be mentioned as typical examples. However, in (A) and (B), a combination of resins which complement each other's drawbacks is used. preferable.

Examples of (A) include EVOH having an excellent gas barrier property, and examples of EVOH (A) include those having an ethylene content of 10 to 70 mol%, preferably 15 to 65 mol%. . Ethylene content 10
If it is less than mol%, the melt moldability will be poor, while if it is 70 mol%, the gas barrier property will be insufficient. The degree of saponification is 90%
The above is preferable, and if it is less than 90%, gas barrier properties and thermal stability are deteriorated. In the present invention, vinyl acetate is mentioned as a typical vinyl ester used in the production of EVOH, but other copolymers such as propylene, butylene and unsaturated may be used as long as the object of the present invention is not impaired. Carboxylic acid or its ester {(meth) acrylic acid, (meth) acrylic acid ester methyl, ethyl)
}, Vinylpyrrolidone (N-vinylpyrrolidone, etc.) vinylsilane compound can be copolymerized, and further, heat stabilizer, ultraviolet absorber, antioxidant, colorant, other resin (polyamide, partially saponified ethylene) -Vinyl acetate copolymer etc.) is also free to blend. Further, a suitable melt index (MI) of EVOH used in the present invention is 190 ° C. under a load of 2160 g: provided that a melting point near 190 ° C. or higher than 190 ° C. is measured under a load of 2160 g at a plurality of temperatures above the melting point,
A value obtained by plotting the reciprocal of the absolute temperature on the horizontal axis and the melt index on the vertical axis in a semi-logarithmic graph, and extruding to 190 ° C) is 0.1 to 50 g / 10 min. , Optimally 0.
5 to 20 g / 10 min. Is.

The thermoplastic resin (B) is not particularly limited, and examples thereof include melt-extrudable thermoplastic resins, liquid crystal resins, inorganic substances, and metals. For example, polyethylene, polypropylene, polyamide, polyester, polycarbonate, polyacrylonitrile. , Polyacrylic acid ester, polymethacrylic acid ester, polystyrene, ethylene-vinyl ester copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene- Methacrylic acid ester copolymer, polyvinyl chloride,
Examples thereof include polyvinylidene chloride, polyvinyl fluoride, silicone resin and low melting point glass.

As a characteristic of the thermoplastic resin (B), a more preferable condition is that the melt viscosity index (melt index: MI) at the molding temperature is similar to that of (A). 50 to 1/50 of (A)
The range is twice, more preferably 20 to 1/20 times, and further preferably 10 to 1/10 times. If it exceeds 50 to 1/50 times, uniform and fine dispersion cannot be achieved and appearance defects such as opacity are likely to occur.

The mixing ratio of (A) and (B) is (A):
(B) = 5: 95 to 95: 5 is preferable, and 10:90 to 90:10 is more preferable. Of these, the smaller amount often aligns vertically in a layered manner.

Further, in order to improve the dispersibility of (A) and (B) and the interfacial adhesion, 0.5 to 20 parts by weight of a compatibilizer is added for the purpose of improving the compatibility of (A) and (B). % May be added, and as the compatibilizing agent, for example, maleic anhydride,
Carboxylic acid, silyl compound, etc. (A) For example, EVO
A thermoplastic resin having a functional group that reacts or interacts with H is effective.

When blending, other additives (plasticizer, heat stabilizer, UV absorber, antioxidant, colorant, filler, other resin, etc.) are used within a range not impairing the object of the present invention. You are free to do anything. In particular, one or more of hydrotalcite-based compounds, hindered phenol-based, hindered amine-based heat stabilizers, metal salts of higher aliphatic carboxylic acids (for example, calcium stearate, magnesium stearate, etc.) are used as a measure for preventing gel formation. Is preferably added in an amount of 0.01 to 1% by weight.

The thickness of the vertically aligned structure (C) of (A) and (B) of the present invention is 1 to 3000 μ, preferably 3 to.
It is 2000μ, and more preferably 5 to 1000μ. Further, it is difficult to measure the concentration distribution of (A) and (B) oriented in a layer shape perpendicular to the surface of the film, sheet or container, but the cross section of the plane perpendicular to the film flow direction is observed with an electron microscope. Then, when the concentration distribution is obtained from the area of the product oriented in the film thickness direction in a layered manner, it is 10% by area or more, preferably 20% or more with respect to the entire area. Here, perpendicular to the surface is 90 ± 60 degrees, preferably 90 ± 4
Means 5 degrees.

The vertically aligned structure (C) can be formed into a film, a sheet or a container (bottle, cup) by a well-known melt molding method or compression molding method. When the vertically aligned structure of the present invention is used as one layer of a multi-layer structure, remarkable features are exhibited, and therefore, this point will be described below. First, as a method for obtaining a multilayer structure, the vertical alignment structure (C) is extrusion laminated with (A), (B) or a thermoplastic resin (D) other than (B) via an adhesive resin. , A dry lamination method, a co-extrusion lamination method, a co-extrusion sheet molding method, a co-extrusion pipe molding method, a co-injection molding method, a solution coating method, etc. to obtain a multilayer structure, and then,
A method of vacuum-pneumatic deep drawing, stretch blow molding of a multilayer structure, and further (A), for example, a method of reheating in a range of not more than melting of EVOH and performing a stretching operation, or the laminate (film or sheet) Examples include a method of subjecting to a biaxial stretching machine and heating and stretching.

Further, the thickness constitution of the multilayer structure is not particularly limited, but in consideration of moldability and cost, the thickness ratio of the (A) layer such as EVOH to the total thickness is 2 to 20. %. Further, the structure of the multi-layer structure includes vertical alignment structure (C) layer / adhesive resin layer / (A) layer, (A) layer / adhesive resin layer / vertical alignment structure (C) layer / adhesive resin Layer / (B) layer, (A) layer / vertical alignment structure (C) layer / adhesive resin layer / (B) layer,
(A) layer / adhesive resin layer / (A) layer / vertical alignment structure (C) layer / adhesive resin layer / (B) layer, (A) layer / adhesive resin layer / (A) layer / adhesion A typical example is a resin layer / vertical alignment structure (C) layer / (B) layer.
When thermoplastic resin layers are provided on both outer layers, the resins may be different or the same. Further, in many cases, scrap such as trim generated at the time of molding is blended with the thermoplastic resin layer, or a recovery layer is separately provided for reuse.

The vertically aligned structure (C) thus obtained can provide a film or sheet excellent in various strengths in the thickness direction, which is the object of the present invention. Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto.

[0021]

【Example】

Example 1 Ethylene content 32 mol%, saponification degree 99.6%, melt index (MI190 ° C., 2160 g load) 1.
5 g / 10 min. MI in 70 parts by weight of EVOH (A)
A resin obtained by blending 30 parts by weight of an ethylene-vinyl acetate copolymer (EVA) resin (B) having a ratio of 1.5 is extruded using FIG. 1 and FIG.
It was subjected to a layer coextrusion device to obtain a multilayer film of linear low-density polyethylene layer / adhesive resin layer / vertical alignment structure layer / adhesive resin layer / linear low-density polyethylene layer. The thickness of each layer was 40/10/20/10 / 40μ, and when the cross section (extrusion direction) of the vertically oriented structure was observed, it was confirmed that EVA was oriented in a layer shape almost perpendicular to the surface of the sheet. Was given. Further, the cross section of the vertical alignment structure layer was immersed in hot xylene (130 ° C.), the polyethylene layer was slightly dissolved, and the concentration of EVA showing the vertical alignment structure was calculated by an electron microscope. As a result, a vertical alignment structure of 25% by area was shown. I confirmed that. An attempt was made to evaluate the adhesiveness of the obtained multi-layered film including the vertically aligned structure layer, but the layers could not be peeled off, and the adhesion was so strong that it could not be measured. In addition, no peeling of the vertically aligned structure layer was observed.

Comparative Example 1 A multilayer film was obtained in the same manner as in Example 1 except that the blend in Example 1 was directly introduced into the extrusion die 6.
The adhesive strength of the multilayer film at a take-up speed of 250 mm / min was a very low value of 150 g / 15 mm width, and since the inside of the blended product layer was peeled off, it is expected that the adhesive strength would be reduced due to peeling within the layer.

Example 2 Ethylene content 32 mol%, saponification degree 99.6%, melt index (MI 190 ° C., 2160 g load) 1.
5 g / 10 min. EVOH (A) of 80% by weight and 6-
A resin blended with 20% by weight of 12 nylon (B) was used in FIGS. 1 and 5 (a) to obtain a single-layer film having a thickness of 20 μm. A stretched nylon film and a polypropylene film on both sides of the film were dry-laminated with an adhesive, and the multi-layer film was made into a water-filled pouch using a heat sealer, and then hot water retort sterilization was performed at 120 ° C. for 30 minutes. . As a result, the obtained pouch had no whitening and had a very good appearance. Further, peeling within the layer of the blend film was not observed.

Comparative Example 2 The same procedure as in Example 2 was carried out except that the blend was directly introduced into the extrusion die 6 in Example 2. In the obtained pouch, whitening and a blend film were observed in the folds and seals.

Example 3 Thermoforming was performed using a three-layer five-layer sheet of polystyrene layer / adhesive resin layer / EVOH layer / adhesive resin layer / polystyrene layer, and after punching out the container, the unnecessary portion (scrap) (Part) for recovery and reuse, pulverized and polystyrene layer / recovery layer / adhesive resin layer / EVOH layer / adhesive resin layer /
A coextrusion sheet of 4 layers and 7 layers of recovery layer / polystyrene layer was prepared. In that case, for the recovery layer, the recovered product (blend) was extruded using (a) of FIGS. 1 and 5. A thermoformed container was prepared from the obtained sheet, filled with water, and the drop impact was evaluated. As a result, the maximum drop height was 1.2 mm.

Comparative Example 3 In Example 3, the recovered substance was directly introduced into the extrusion 6, and otherwise the same as in Example 1 to prepare a 4-kind 7-layer sheet including a recovered layer. The drop impact height of the thermoformed container made of the obtained sheet was 0.5 mm.

[0027]

EFFECT OF THE INVENTION Adhesive strength of the blend composition layer of the thermoplastic substances (A) and (B) is reduced due to peeling within the layer, impact strength is deteriorated, transparency is reduced due to occurrence of voids in the layer, and whitening is prevented and improved. can do.

[Brief description of drawings]

FIG. 1 is a schematic view of a manufacturing process of the present invention.

FIG. 2 is a schematic view of another manufacturing process of the present invention.

FIG. 3 is a schematic view of another manufacturing process of the present invention.

FIG. 4 is a schematic view of another manufacturing process of the present invention.

5 is a cross-sectional view showing an aspect of kneading in the second step of FIG. 1 of the present invention.

[Explanation of symbols]

 1 Melt-kneaded body 2 Melt-kneaded body after stretching 3 Melt-kneaded body kneaded by a rotating body 4 Melt-kneaded body after compression 5 Melt-kneaded body rotated by 90 degrees 6 Die 7 Extruded sheet 8 Extruded sheet (thickness Cross-section in the direction) 9 Double cylindrical rotary kneader 10 Motor

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area B29L 7:00 22:00

Claims (2)

[Claims] 1. A film or sheet comprising at least two thermoplastics (A) and (B), wherein (A) and / or (B) is oriented in a layered manner perpendicular to the surface of the film, sheet or container. Or container. 2. A melt-kneaded product of at least two thermoplastic substances (A) and (B) is stretched in at least one direction,
Next, after rotating the stretched melt-kneaded product by 90 ± 20 °,
(A) and / or (B) characterized by being molded
A method for producing a film, sheet or container in which is oriented in layers in a direction perpendicular to the surface of the film, sheet or container.