JPH0827332A - Resin composition and multilayer structure - Google Patents

Abstract

PURPOSE:To obtain a resin compsn. which is used for a multilayer structure, has a good compatibility, and does not exhibit any abnormal flow by compounding a polyolefin resin, a saponified ethylene-vinyl ester copolymer, and a specific olefin copolymer in a specified wt. ratio. CONSTITUTION:A polyolefin resin (A), a saponofied ethylene-vinyl ester copolymer (B) having an ethylene content of 10-70mol%, a degree of saponification of vinyl ester units of 80% or higher, and an m.p. of 125-220 deg.C, and an olefin- unsatd. dicarboxylic anhydride-unsatd. carboxylic ester or -vinyl ester copolymer (C) are compound in wt. ratios of component (A)/component (B) and component (C)/the sum of components (A) and (B) of (1:99)-(40:60) and (0.1:99.9)-(20:80), respectively. Pref., 0.0001-2wt.% [based on the sum of components (A) and (B)] hydrotalcite compd. is added to the resulting compsn., and still pref., 0.0001-2wt.% (based on the same as above) metal salt of a higher fatty acid is further added.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a resin composition having good compatibility and having no abnormal flow, and having a beautiful appearance, impact resistance,
The present invention relates to a multilayer structure having excellent delamination resistance and gas barrier properties.

[0002]

2. Description of the Related Art A thermoplastic resin having excellent moisture resistance and mechanical properties, especially a layer of polyolefin resin (hereinafter referred to as PO) and a saponified ethylene-vinyl ester copolymer excellent in oxygen barrier property (hereinafter referred to as EVOH) Multilayer plastic packaging material in which layers and layers are laminated via an adhesive resin is a bottle,
It is widely used in various fields such as foods, cosmetics, medicinal chemicals and toiletries as a container having an excellent oxygen barrier property in the form of a cup, a pouch, or the like. When manufacturing such a multi-layer plastic container, burrs due to pinch-off are inevitable in blow molding of bottles, etc., and regrind (scrap) such as punching scraps inevitably occurs in cup molding, and its recycling is costly. It is also needed from the viewpoint of resource saving. In order to effectively reuse this regrind, a method in which a regrind is mixed with a thermoplastic resin layer of a main material such as polyolefin (Japanese Patent Publication No. 59-294).
09), a thermoplastic resin layer such as polyolefin and EVOH
A method of interposing a regrind layer between the layer and the layer (Japanese Patent Laid-Open Publication No. 5 (1999) -58242).
9-101338) has been proposed. However,
Many thermoplastics, especially polyolefins and EVs
When a regrind resin containing OH is simultaneously melt-extruded, EVOH tends to deteriorate, and black deposits (burns) or the like are generated inside the extruder during mixed melt extrusion, or adhere to a die lip or the like during extrusion. Gel-like substances (meyer's) etc. are generated, non-uniform phase-separated foreign matter or abnormal flow occurs, and this causes deterioration of the appearance characteristics of the container,
Due to the generation of odor, etc. of resin decomposition products and the deterioration of mechanical properties such as impact resistance, it is often the case that extrusion molding cannot be carried out at all, or even if it does, it can only be operated for a short time. Is. Further, when a blend of polyolefin and EVOH and EVOH are coextruded, a wavy pattern is generated on the surface of the molded product, and delamination (intra-layer and inter-layer peeling) also occurs.

Further, a thermoplastic polymer (ionomer, maleic anhydride grafted polypropylene, etc.) having a carbonyl group in the main chain or side chain in low density polyethylene and EVOH.
To improve processability by blending an ethylene-maleic anhydride copolymer etc. {JP-A-49-570
No. 86 (US Pat. No. 3,931,449)}, to improve the appearance of a molded article by blending a polyolefin and EVOH with a graft-modified polyolefin having a high ethylene content EVOH and an unsaturated carboxylic acid.
No. 2539 (EP401666)}, it is described that the environmental stress crack resistance is improved by blending polyolefin and EVOH with a polyolefin modified with an unsaturated carboxylic acid (JP-A-5-98084). However, as is clear from Comparative Examples 5 to 7 and 12 to 14 to be described later, in compositions using ionomer, maleic anhydride grafted polypropylene, ethylene-maleic anhydride copolymer and the like, impact resistance and in-layer peel strength are found. Is insufficient in terms of.

It is also possible to improve impact resistance by blending an ethylene-unsaturated dicarboxylic acid anhydride-unsaturated ester copolymer having 4 to 12 carbon atoms with polypropylene. USP461996
9). Further, it is possible to suppress the whitening phenomenon due to mechanical rubbing by blending a thermoplastic resin (EVOH or the like) with an inorganic filler and an ethylene-acrylic acid ester-maleic acid derivative copolymer.
No. 6163. However, JP-A-61-111346 (USP4619969) and JP-A-2-16163 do not describe the use of ethylene-maleic anhydride-acrylic acid ester copolymer as a compatibilizer for EVOH and polyolefin. .

[0005]

DISCLOSURE OF THE INVENTION The present invention has no wave pattern for the purpose of eliminating flow abnormalities such as charring and eye blemishes, and effectively reusing scrap compositions such as regrind. The object of the present invention is to obtain a molded product having a beautiful appearance and excellent impact resistance, delamination resistance, and gas barrier property, particularly a multilayer structure.

[0006]

[Means for Solving the Problems] The above objects are the polyolefin resin (A) {PO (A)} and the ethylene content of 10
-70 mol%, saponification degree of vinyl ester component of 80% or more, and melting point of 125-220 ° C ethylene-vinyl ester copolymer saponified product (B) {EVOH (B)} and olefin-unsaturated dicarboxylic acid anhydride By further providing a resin composition comprising a compound-unsaturated carboxylic acid ester or vinyl ester copolymer (C) {modified PO (C)} and satisfying the following formulas (I) to (II), Layer containing the resin composition and ethylene content of 10 to 70
It is achieved by providing a multilayer structure comprising at least two layers containing EVOH (B) having a mol% and a saponification degree of a vinyl ester component of 90% or more. 1/99 ≦ weight of EVOH (B) / weight of (A) ≦ 40/60 (I) 0.1 / 99.9 ≦ X ≦ 20/80 (II)

In the present invention, PO (A) means polyethylene resin, polypropylene resin, polystyrene resin, ionomer, ethylene-vinyl acetate copolymer,
Homopolymers of various olefins such as ethylene- (meth) acrylic acid ester copolymers, ethylene-propylene copolymers, ethylene-butylene copolymers, copolymers of various olefins and monomers copolymerizable therewith Of these, polyethylene resins (low density polyethylene,
Medium density polyethylene, high density polyethylene, linear low density polyethylene), polypropylene resin, ethylene-
Suitable examples include propylene copolymers and ethylene-butylene copolymers. Suitable melt index (MI) of PO (A), especially polyethylene resin
(190 ° C, under 2160g load) 0.01 to 100g
/ 10 minutes, particularly preferably 0.01 to 50 g / 1
0 minutes, 0.01 to 30 g / 10 minutes, optimally 0.01 to 10 g / 10 minutes.

EVOH (B) is a saponification product of an ethylene-vinyl ester copolymer and has an ethylene content of 1
0 to 70 mol%, preferably 20 to 65 mol%, optimally 20 to 53 mol%, and the saponification degree of the vinyl ester component is 80% or more, preferably 85% or more, optimally 90%. % Or more. The melting point of EVOH (B) is selected from 125 to 220 ° C, preferably 130 to 220 ° C, and most preferably 135 to 220 ° C. When the ethylene content is below the above range and the melting point is above the above range, the melt moldability is poor, while when the ethylene content is above the above range, the gas barrier property is insufficient. When the saponification degree is below the above range and the melting point is below the above range, gas barrier properties and thermal stability are poor, gel
The amount of seeds generated increases. This is because Comparative Example 15 described later.
Is clear from. The ethylene content and saponification degree of EVOH can be determined by a nuclear magnetic resonance (NMR) method, and the melting point can be determined by a differential thermal analysis (DSC) method (scanning speed 10 ° C./min). Also, the preferred melt index (MI) of EVOH used in the present invention
(Under 230 ° C. and 2160 g load) is 0.5 to 200 g /
10 min. Optimally 2 to 80 g / 10 min. Is.

In the present invention, vinyl acetate is representatively used as the vinyl ester used in the production of EVOH, but other fatty acid vinyl esters (vinyl propionate, vinyl pivalate, etc.) can also be used. In addition, when the EVOH contains 0.0002 to 0.2 mol% of a vinylsilane compound as a copolymerization component, the consistency of the melt viscosity between the substrate and the EVOH is improved, and a homogeneous coextruded multilayer film can be produced. EV not only possible
When blending OHs, the dispersibility is improved, which is effective in terms of improving moldability and the like. Here, as the vinylsilane-based compound, for example, vinyltrimethoxysilane,
Examples thereof include vinyltriethoxysilane, vinyltri (β-methoxy-ethoxy) silane, and γ-methacryloxypropylmethoxysilane. Of these, vinyltrimethoxysilane and vinyltriethoxysilane are preferably used. Further, other comonomer [eg, propylene, butylene, unsaturated carboxylic acid or ester thereof ((meth) acrylic acid, methyl (meth) acrylate, (meth) acrylic) is used as long as the object of the present invention is not impaired. Ethyl acidate}, vinylpyrrolidone (N-vinylpyrrolidone, etc.)
Can also be copolymerized. Further, in the present invention, two or more kinds of EVOH (B) can be blended and used, and a heat stabilizer, an ultraviolet absorber, an antioxidant, a coloring agent, a filler within a range not impairing the object of the present invention. Other resins (polyamide, partially saponified ethylene-vinyl acetate copolymer, etc.) can be blended.

In the present invention, the content of each component of olefin-unsaturated dicarboxylic acid anhydride-unsaturated carboxylic acid ester or vinyl ester copolymer (C) {modified PO (C)} is 10 97% by weight, 1 to 50% by weight of unsaturated dicarboxylic acid anhydride component, 1 to 50% by weight of unsaturated carboxylic acid ester or vinyl ester component are preferred, and 20 to 95% by weight of ethylene component, unsaturated dicarboxylic acid anhydride component. 1-40% by weight,
Unsaturated carboxylic acid ester or vinyl ester component 2
Is preferably 45 to 45% by weight, optimally 20 to 95% by weight of ethylene component, 1 to 30% by weight of unsaturated dicarboxylic acid anhydride component, and 2 to 45% by weight of unsaturated carboxylic acid ester or vinyl ester component. .

When the content of each component satisfies the above range, a more excellent object of the present invention can be obtained. Particularly, the content of unsaturated dicarboxylic acid anhydride component is 1 to 50.
When it is applied to the reuse of the recovered material when it satisfies the weight%, the recoverability improving effect is sufficient, and the heat stability is excellent.
There are few gels and spots. When the content of the unsaturated carboxylic acid ester or vinyl ester component satisfies 1 to 50% by weight, EVOH is easily finely dispersed, and the compatibility between PO (A) and EVOH (B) is further improved.
Further, the impact resistance of the obtained resin composition is improved.

Examples of the olefin of the modified PO (C) include ethylene, propylene, n-butylene, iso-butylene, styrene, etc. Of these, ethylene is preferable for obtaining a more excellent object of the present invention. Further, examples of the unsaturated dicarboxylic acid anhydride of the modified PO (C) include maleic anhydride, itaconic anhydride, citraconic anhydride, and of these, maleic anhydride is preferable.

The unsaturated carboxylic acid ester of modified PO (C) includes methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid. Examples thereof include cyclohexyl, fumaric acid monoethyl ester, fumaric acid monomethyl ester, and the like, and modified PO (C) vinyl esters include fatty acid vinyl esters such as vinyl acetate, vinyl propionate, and vinyl pipariate. Of these, (meth) acrylic acid ester and vinyl acetate
The compatibility between PO (A) and EVOH (B) is further improved, and impact resistance is improved. The preferred melt index (MI) of the modified PO (C) (190 ° C., under a load of 2160 g) is 0.1 to 100 g / 10 minutes, and more preferably 0.5 to 50 g / 10 minutes.

In the present invention, it is important to use a copolymer of an olefin, an unsaturated dicarboxylic acid anhydride and an unsaturated carboxylic acid ester or a vinyl ester as the modified PO (C), and the unsaturated dicarboxylic acid anhydride is used. In the case where the polyolefin is graft-polymerized with a polyolefin, gel and lumps, which are considered to be due to deterioration of thermal stability, are remarkably generated as the content of the unsaturated dicarboxylic acid anhydride is increased, which is not preferable. However, it is free to use such a graft polymer in combination so long as the object of the present invention is not impaired.

In the resin composition of the present invention, EVOH
Weight ratio of (B) / PO (A) is 1/99 to 40/60
And preferably 2/98 to 30/70. 1/9
When it is less than 9, relatively good moldability is exhibited without adding the modified PO (C), but the gas barrier property is deteriorated, which is not preferable. On the other hand, if it exceeds 40/60, modified PO
Even if (C) is added, the desired performance cannot be obtained.

Next, modified PO (C) / {EVOH (B)
And PO (A)} total weight ratio is 0.1 / 99.9-
20/80, preferably 0.5 / 99.5-18 /
82. If it is less than 0.1 / 99.9, the desired performance of the present invention cannot be obtained. On the other hand, if it exceeds 20/80, it is not preferable in terms of thermal stability such as formation of spots and gel.

PO (A), EVOH (B) and modified PO
The method of blending (C) is not particularly limited, and the thermoplastic resin is dry-blended and used as it is, or more preferably by a Banbury mixer, a single-screw or twin-screw extruder. There are methods such as pelletizing and drying. If the blend is non-uniform, or if there are gels, lumps, or inclusions during the blend pelletizing operation, cracks are likely to occur, so use an extruder with a high degree of kneading during the blend pelletizing operation, and use the hopper. It is desirable to seal the mouth with nitrogen and extrude at a low temperature. However, in order to show more performance, PO
PO (C) modified to (A) and / or EVOH (B)
Is preferably melt-mixed in advance, blended with PO (A) and / or EVOH (B), melt-mixed, and molded. By molding by such a method, the appearance of the molded product is further improved, and the scrap recoverability is also significantly improved. Although the reason for improving the moldability is not clear, when EVOH (A) and modified PO (C) are kneaded in advance, both resins are mixed in a molecular order,
A composition that combines the properties of both is created, and EVOH
It is expected that the compatibility between (B) and PO (A) will increase, and as a result, the three components will be dispersed uniformly, and the quality and moldability will be greatly improved.

A molded product, particularly a multilayer structure, using the resin composition thus obtained has few wavy patterns, gels and spots and is excellent in impact resistance and intra-layer peeling resistance. There is. This is clear from Examples 6 and 10 described later.

The resin composition of the present invention contains the hydrotalcite compound (D) in an amount of 0.0001 to 2%, preferably 0.00, based on the total weight of PO (A) and EVOH (B).
By blending 001 to 1%, the in-layer peel strength of the layer made of the resin composition of the present invention can be further improved. This also applies to Examples 1 to 4 and 8 to be described later.
It is clear from 9.

[0020] Here, in particular _{M x Al y (OH) 2x} + 3y-2z (A) Z · aH 2 O as hydrotalcite compound
(M is Mg, Ca or Zn, A is CO ₃ or HP
_{O 4, x, y, z} , a may be mentioned hydrotalcite compound is a double salt represented by positive numbers), with this arrangement, is illustrated in particular include: Preferred ones It

Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O Mg ₈ Al ₂ (OH) ₂₀ CO ₃ .5H ₂ O Mg ₅ Al ₂ (OH) ₁₄ CO ₃ .4H ₂ O Mg ₁₀ Al ₂ ( _{OH) 22 (CO 3) 2} · 4H 2 O Mg 6 Al 2 (OH) 16 HPO 4 · 4H 2 O Ca 6 Al 2 (OH) 16 CO 3 · 4H 2 O Zn 6 Al 6 (OH) 16 CO 3・ 4H ₂ O Mg _4.5 Al ₂ (OH) ₁₃ CO ₃・ 3.5H ₂ O

As the hydrotalcite compound,
The hydrotalcite-based solid solution described in JP-A-1-308439 (USP4954557), for example, the following may also be used. [Mg _0.75 Zn _0.25 ] _0.67 Al _0.33 (OH) ₂ (CO ₃ )
_0.167・ 0.45H ₂ O [Mg _0.79 Zn _0.21 ] _0.7 Al _0.3 (OH) ₂ (CO ₃ )
_0.15

In the resin composition of the present invention, the metal salt (E) of higher aliphatic carboxylic acid is added to PO (A) and EVOH.
By blending 0.0001 to 2%, preferably 0.001 to 2% with respect to the total weight of (B), impact strength and the like can be further improved. This is also apparent from Example 5 described later. Here, the metal salt of higher aliphatic carboxylic acid is a metal salt of higher fatty acid having 8 to 22 carbon atoms, and as the higher fatty acid having 8 to 22 carbon atoms,
Lauric acid, stearic acid, myristic acid, etc. may be mentioned, and as the metal, periodic table I, II or II.
Group I metals (sodium, potassium, magnesium, calcium, zinc, barium, aluminum, etc.) can be mentioned. Of these, Group II metals are preferred.

In the resin composition of the present invention, the alkali metal compound (F) is converted into an alkali metal ion to obtain E.
By containing 5 to 5000 ppm with respect to VOH (B), flow abnormalities such as charring and eye blemishes are eliminated, and therefore scrap recovery performance is greatly improved. The more preferable content of the alkali metal ion is 20 to 1000 p.
pm, further 30 to 500 ppm. Examples of the alkali metal ion include lithium ion, sodium ion, potassium ion and the like, and examples of the alkali metal compound include monovalent metal aliphatic carboxylate, aromatic carboxylate, phosphate and metal complex. Can be mentioned. Examples thereof include sodium acetate, potassium acetate, sodium phosphate, lithium phosphate, sodium stearate, potassium stearate, and a sodium salt of ethylenediaminetetraacetic acid. Of these, sodium acetate, potassium acetate, sodium phosphate, lithium phosphate, sodium stearate and potassium stearate are preferable.

In the resin composition of the present invention, the above (D) and (E) are used in combination, (D) and (F) are used in combination, (E) and (F) are used in combination, and Is a more preferable embodiment in which (D), (E) and (F) are used in combination. PO (A) and EVOH (B) or P
A scrap containing O (A), EVOH (B), an adhesive resin, etc. is blended with modified PO (C) or modified PO (C) and the above (D), (E) or (F) to obtain moldability. In the case of improvement, rather than adding the modified PO (C) and / or (D), (E) or (F) to the scrap composition as it is, these additives are added with a polyolefin resin such as polyethylene or polypropylene. 2 to
Mixing after diluting 100 times is more effective, probably because the dispersibility with scrap is improved.

Further, in the resin composition of the present invention, in order to enhance the effects of the present invention, one or more of hindered phenol-based and hindered amine-based heat stabilizers may be used as PO (A) and EVOH (B). ) To the total weight of.
It is also possible to add 01 to 1% by weight. Further, other additives (plasticizer, heat stabilizer, ultraviolet absorber, antioxidant, colorant, filler) can be blended.

Further, in the present invention, PO (A), EVO
When blending H (B) and modified PO (C),
A small amount, for example, 20% by weight or less of an adhesive resin (hereinafter referred to as AD) for adhering (A) and EVOH (B) can be blended. The AD to be used is not particularly limited, but an adhesive resin used when manufacturing a multilayer structure described later is exemplified.

The layer containing the resin composition of the present invention and the layer containing EVOH having an ethylene content of 10 to 70 mol% and a saponification degree of the vinyl ester component of 90% or more are laminated, particularly by coextrusion to form a gas. It is possible to obtain a multilayer structure having excellent barrier properties and good appearance. The EVOH used for this multilayer structure has an ethylene content of 10 to 10.
It is important to be 70 mol%, preferably 20 to 65
Mol%, and more preferably 20 to 53 mol%. When the ethylene content is less than 10 mol%, the melt moldability is poor, and when it is 70 mol% or more, the gas barrier property is insufficient. It is important that the degree of saponification is 90% or more, preferably 9
It is 5% or more. If the degree of saponification exceeds 90%, the gas barrier property becomes insufficient. The multilayer structure of the present invention has an inner layer,
A layer that protects the EVOH layer, preferably a thermoplastic resin layer, may be laminated on the outer layer or the inner and outer layers.

The thickness of the EVOH layer responsible for the gas barrier property is selected from the range of 5 to 250 μ, preferably 10 to 100 μ. The thickness of the resin composition layer is 10 to 3000.
μ, preferably 100 to 3000 μ.
The thermoplastic resin used for the inner and outer layers is used to impart moisture permeability, heat resistance, heat sealability, and mechanical properties to the multilayer structure, and further deteriorates the gas barrier property due to the entry of moisture into the EVOH layer. It is also used to prevent The thermoplastic resin is not particularly limited, but the polyolefin (A), polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene- Acrylic ester-based copolymer, polypropylene, polystyrene-based resin and other polyolefins described above (A)
Examples include {PO (A)}, polyamide-based resin, polyester-based resin, polycarbonate-based resin, polyurethane-based resin, polyvinyl chloride-based resin, and the like, and among them, the above-mentioned polyolefin (A) such as high-density polyethylene and polypropylene is preferable. Used for. Additives such as the above-mentioned antioxidants, colorants, and fillers may be added to these resin layers.

When obtaining the multilayer structure of the present invention, an interlayer adhesive resin (AD) can be used if necessary. The adhesive resin (AD) is not particularly limited as long as it firmly adheres the layers, but unsaturated carboxylic acid or its anhydride (maleic anhydride, etc.) is used as polypropylene or polyethylene. , Etc., or a copolymer of ethylene and a monomer (vinyl acetate, acrylate, etc.) capable of copolymerizing ethylene with ethylene (for example, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid). What was grafted to the ester (methyl ester or ethyl ester) copolymer}
It is preferably used.

As a method for obtaining a multilayer structure, an extrusion laminating method, a dry laminating method, a coextrusion laminating method, a coextrusion sheet molding method, a coextrusion inflation molding method, a solution coating method and the like are often used via an adhesive resin. However,
A coextrusion melt molding method is suitable for the portion where the resin composition of the present invention and EVOH are laminated. In this case, PO
PO (C) modified to (A) and / or EVOH (B)
Can be melt-mixed in advance, and the resin composition composed of (A), (B) and (C), which is blended with PO (A) and / or EVOH (B), and EVOH can be co-extruded and melt-molded. This is preferable because the appearance of the multilayer structure is improved and the scrap recoverability is also significantly improved. The multi-layer structure thus obtained is reheated within a range not higher than the melting point of EVOH and uniaxially or biaxially stretched by a roll stretching method, a pantograph type stretching method, an inflation stretching method or the like to obtain a desired molded article. Obtainable. Further, the EVOH layer and the thermoplastic resin layer may be crosslinked by irradiating the multilayer structure with radiation or electron beam, or may be chemically crosslinked by adding a chemical crosslinking agent during extrusion molding.

Further, the parison thus obtained,
A container having physical properties characterized by mechanical properties, gas barrier properties, etc. by performing stretching such as uniaxial stretching, biaxial stretching, or blow stretching of a multilayer structure such as a film or sheet, or by thermoforming (Bottles, cups, etc.) can be obtained. Here, the thermoforming means an operation in which the sheet is heated and softened in advance and then deformed by the plug and the vacuum pressure and at the same time cooled to form the cup. Further, the heating may be a method in which the sheet is left at a temperature necessary for deformation for a predetermined time and is operated so that the sheet is thermally substantially uniform. In consideration of operability, heating is performed with various heaters. A homogenizing method is preferred.

The thickness constitution of the multilayer structure is not particularly limited either, but in consideration of moldability and cost, the thickness ratio of the EVOH layer to the total thickness is 0.
5 to 20% is preferable, and 1 to 10% is particularly preferable. In addition, the structure of the multilayer structure is EVOH / A
D / resin composition / PO, EVOH / AD / PO resin composition, EVOH / AD / resin composition / AD / PO, PO /
Typical examples include AD / EVOH / AD / resin composition / PO, resin composition / AD / EVOH / AD / resin composition / PO, resin composition / AD / EVOH / AD / PO. When a PO layer is provided on both outer layers, the resins may be different or the same.

In such a multilayer structure, scraps of the multilayer structure can be used as a raw material for the resin composition of the present invention. Further, scraps of other polyolefin moldings can be mixed and used. The multilayer structure having the above layer structure is an EVOH having excellent gas barrier properties.
Therefore, it is useful as a food packaging material, a medical product (medicine, medical device, etc.) packaging material, and an industrial material, which are particularly required to have a gas barrier property. It is also particularly useful as a material for fuel containers such as gasoline or fuel transfer pipes.

There are 40 fuel containers (tanks) such as gasoline.
Since it is a large size of ~ 70 liters, excellent impact resistance is required, and as a material satisfying this requirement, the melt index (MI) (190 ° C, under a load of 2160 g) is 0.0.
1 to 50 g / 10 minutes, especially 0.01 to 30 g / 10
Min, optimally 0.01 to 10 g / 10 min polyethylene, particularly high density polyethylene is preferably used. However, when collecting and reusing scraps generated during the manufacturing of a tank composed of such a low-MI high-density polyethylene layer and EVOH layer, if the difference between the MI of high-density polyethylene and the MI of EVOH is too large, compatibility is high. Is insufficient, a wave pattern is generated in the scrap layer, and the impact resistance is not sufficient.

The present invention has solved this problem brilliantly. That is, PO (A), especially low-MI high-density polyethylene (A) and EVOH (B) modified PO (C), or further modified PO (C) and the above-mentioned (D), (E) or (F) By blending and, the above-mentioned problems can be solved. Furthermore, when collecting and reusing the scrap of a multilayer container with a thick EVOH layer, the EV in the scrap
When the content of OH is high, for example, 10 to 40% by weight, the impact resistance and in-layer peeling property of the scrap layer are not sufficient. The present invention has solved this problem.

The industrial significance of the present invention, which makes it possible to recover and reuse scrap of containers such as gasoline tanks having a PO layer and an EVOH layer, is extremely significant.

[0038]

The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Example 1 Polypropylene (PO (A), manufactured by Mitsubishi Petrochemical Co., Ltd., M
80 parts by weight of A-6), an ethylene content of 31 mol% containing 50 ppm of sodium ions as EVOH (B),
Saponification degree 99.5%, melt index (MI 230
℃ 2160g load) 7.0g / 10min, melting point 183 ℃
10 parts by weight of EVOH, 5 parts by weight of terpolymer of ethylene (60% by weight) -maleic anhydride (4% by weight) -ethyl acrylate (36% by weight) as modified PO (C),
Further, as AD, 5 parts by weight of maleic anhydride graft-modified polypropylene (QF-500, manufactured by Mitsui Petrochemical),
And hydrotalcite {Mg _4.5 Al ₂ (OH) ₁₃ C
O ₃ · 3.5H ₂ O} (DHT-4A) was dry blended with 0.1 part by weight, and then the diameter was 40 mm, L / D = 24,
Melt extrusion was performed with a screw having a Maddock type kneading section with a compression ratio of 3.8 to obtain pellets of the resin composition. Charge this resin composition and the above-mentioned PO (A), EVOH (B), and AD into separate extruders, and PO (A) / AD / EVOH
(B) / AD / resin composition / PO (A) (film thickness: 15
0 μ / 25 μ / 100 μ / 25 μ / 600 μ / 100
A multi-layer sheet having a total thickness of 1000 μ having a configuration of (μ) was obtained by a coextrusion sheet forming apparatus of 4 types and 6 layers. For extrusion molding, PO (A) has a diameter of 65 mm and an extruder equipped with a single screw L / D = 22 is set to a temperature of 200 to 240 ° C.,
EVOH (B) has a diameter of 40 mm and an extruder equipped with a L / D = 26 single screw at a temperature of 170 to 210 ° C., and AD has a diameter of 40 mm and an extruder equipped with a L / D = 26 single screw of 160. The temperature was ˜220 ° C., the resin composition was 40 mm in diameter, and the extruder equipped with a single screw of L / D = 22 was operated at 160 ° C. to 210 ° C., and the feed block die (width 600 mm) was operated at 240 ° C. . A sheet with a good appearance can be obtained even after continuous operation for 24 hours, and there is no or almost no phase-separated foreign matter due to poor compatibility, wavy pattern, abnormal flow (burns, eye stains), or in the resin composition layer. Delamination (whitening of the edge at the time of cutting the sheet) was slightly observed, but was not remarkable and was at a level that could withstand use. Further, by a known thermoforming method (vacuum pressure air forming), a cup (drawing ratio = 1/2) was formed at a sheet temperature of 170 ° C, and after filling with water, the bag was dropped and broken at 5 ° C. Does not break the bag, and the peel strength of the flange portion of the cup (peeling of the composition layer within the layer) {T
The value measured by the mold peeling test (peeling speed 250 mm / min) was 1.2 kg / 15 mm width, which was a practical level.

Example 2 Using the coextrusion sheet molding apparatus used in Example 1, PO
(A) / AD / EVOH (B) / AD / PO (A) (Film thickness: 425 μ / 25 μ / 100 μ / 25 μ / 425
A multi-layer sheet of 5 layers of 3 types of (μ) was obtained. 95 parts by weight of this crushed scrap was dry-blended with 5 parts by weight of the modified PO (C) used in Example 1 and 0.1 part by weight of hydrotalcite used in Example 1, and an extruder having a diameter of 40 mm was used again. And pelletized. Using this resin composition, a cup was obtained in the same manner as in Example 1 and evaluated.
It has been found that as shown in FIG.

Example 3 In Example 2, instead of EVOH (B), Example 1 was used.
2 parts by weight of modified PO (C) and EVOH (B) 10 used in
Parts by weight were dry blended and the EVOH composition pelletized using an extruder having a diameter of 40 mm was used.
(A) / AD / EVOH composition / AD / PO (A) (film thickness: 425 μ / 25 μ / 100 μ / 25 μ / 425
A multi-layered sheet having a thickness of 1000 μm was obtained. 97 parts by weight of crushed scraps of this sheet were blended with 3 parts by weight of the modified PO (C) used in Example 1 and 0.1 parts by weight used in Example 1 and pelletized again using an extruder having a diameter of 40 mm. Was made. Using this resin composition, a cup was obtained in the same manner as in Example 1 and evaluated. As a result, as shown in Table 1, it was found that the cup showed better performance than Example 1.

Examples 4 to 7 A cup was obtained in the same manner as in Example 2 except for the conditions shown in Table 1.
An evaluation was made. The results are shown in Tables 1 and 2.

Comparative Examples 1 to 7 A cup was obtained in the same manner as in Example 2 except for the conditions shown in Table 1.
An evaluation was made. The results are shown in Tables 1 and 2.

Examples 8 to 11 Using the coextrusion sheet molding apparatus used in Example 1, PO
(A) / AD / EVOH (B) / AD / PO (A) (Film thickness: 425 μ / 25 μ / 100 μ / 25 μ / 425
A multi-layered sheet of 3 types and 5 layers was obtained. 95 parts by weight of this crushed scrap was dry-blended with 5 parts by weight of the modified PO (C) used in Example 1 and 0.1 part by weight of hydrotalcite used in Example 1, and an extruder having a diameter of 40 mm was used again. And pelletized. Using this resin composition, a cup was obtained in the same manner as in Example 1, and the evaluation results were shown in Table 3.
~ 4. As PO (A), high density polyethylene (HDPE) (MI = 0.05 g / 10 minutes) is used, and the extrusion molding temperature of PO (A) is 220 to 240 ° C.
And

Comparative Examples 8 to 15 A cup was obtained in the same manner as in Example 2 except for the conditions shown in Table 3.
An evaluation was made. The results are shown in Tables 3 to 4.

Example 12 Instead of 5 parts by weight of modified PO (C) and 0.1 parts by weight of DHT-4A used in Example 2, PO (C) and DH were used.
Composition obtained by diluting T-4A with low density polyethylene (LDPE) {LDPE / modified PO (C) = 50% by weight / 50
A mixture of 0.3% by weight of DHT-4A and 1% by weight} 1
A cup was obtained and evaluated in the same manner as in Example 2 except that 0 part by weight was used. As a result, there were no wavy patterns, gels, and spots.
Showed width.

Example 13 PO (C) and DHT-4A added in Example 12
A cup was obtained in the same manner as in Example 12 except that 10 parts by weight of the composition was replaced by 5 parts by weight, and the evaluation was made. Internal peeling showed a width of 2.1 kg / 15 mm.

Example 14 Example 13 was repeated except that the amount of DHT-4A added, 0.3 wt%, was changed to 0.6 wt%.
A cup was obtained and evaluated in the same manner as in. as a result,
There were no wavy gel spots, and the bag had a falling bag 2.4 m and an intralayer peel strength of 2.4 kg / 15 mm width.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

[0051]

[Table 4]

[0052]

EFFECT OF THE INVENTION The resin composition of the present invention has good compatibility and no abnormal flow, and the multilayer structure comprising the resin composition layer and the EVOH layer does not have gels, spots, or waviness and has an appearance. Not only is it beautiful, but it is also excellent in impact resistance and in-layer peeling resistance.

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Claims (5)

[Claims] 1. A saponified ethylene-vinyl ester copolymer having a polyolefin resin (A), an ethylene content of 10 to 70 mol%, a saponification degree of a vinyl ester component of 80% or more, and a melting point of 125 to 220 ° C. A resin composition comprising B) and an olefin-unsaturated dicarboxylic acid anhydride-unsaturated carboxylic acid ester or vinyl ester copolymer (C) and satisfying the following formulas (I) to (II). 1/99 ≦ (B) weight / (A) weight ≦ 40/60 (I) 0.1 / 99.9 ≦ X ≦ 20/80 (II) where X = (C ) Weight / total weight of {(A) and (B)} 2. The resin composition according to claim 1, further comprising a hydrotalcite compound (D), and the weight of (D) is 0 relative to the total weight of {(A) and (B)}. .000
The resin composition according to claim 1, which is 1 to 2%. 3. The resin composition according to claim 1, further comprising a metal salt (E) of a higher aliphatic carboxylic acid, and (E)
Is 0.00 based on the total weight of {(A) and (B)}
The resin composition according to claim 1, which is 01 to 2%. 4. The resin composition according to claim 2, further comprising a metal salt (E) of a higher aliphatic carboxylic acid, and (E)
Is 0.0 with respect to the total weight of {(A) and (B)}.
The resin composition according to claim 2, which is 001 to 2%. 5. A resin composition layer according to claim 1 and at least two layers of an ethylene-vinyl ester copolymer saponification layer having an ethylene content of 10 to 70 mol% and a vinyl ester component saponification degree of 90% or more. Multi-layer structure.