JP3529893B2 - Resin composition and multilayer structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition and a multi-layer structure having excellent permeation-preventing performance (barrier property) and impact resistance against gas, solvent and the like, and more particularly, to an oxygen-containing organic compound and a hydrocarbon. The present invention relates to a resin composition and a multilayer structure suitable for a fuel container or a fuel pipe having an excellent barrier property against a mixture such as gasoline containing methanol.

[0002]

2. Description of the Related Art Conventionally, in order to accommodate cosmetics, foods, medical products, or chemicals that are easily altered by air, synthetic resin multi-layer containers made of various thermoplastic laminates and single layers containing barrier components. Containers and the like are known. And
On the other hand, in recent years, for example, a fuel tank of a vehicle such as an automobile has been proposed and put into practical use in order to reduce its weight and facilitate its molding process. As a plastic fuel tank, a polyethylene single-layer type is widely used, but it has a drawback of having relatively high permeability. On the other hand, conventionally, a method of improving the barrier property by a sulfone treatment or a freon treatment in a polyethylene tank, a method of mixing a substance having a barrier property into polyethylene, or, on the other hand, a multilayer structure and a barrier layer There has been proposed a three-kind five-layer structure in which nylon is used as the material and a high-density polyethylene layer is provided on both sides thereof with an adhesive layer interposed therebetween.

[0003]

However, in the case of a single-layer container containing a component having a barrier property, the barrier property against necessary chemicals is insufficient, or in the case of a laminated body, the durability of the entire container is reduced. It has the drawback of lacking impact resistance. On the other hand, in the recent tightening of regulations on environmental pollution, methanol, MTBE (methyl tertiary butyl ether), etc., which are mainly used in the United States for improving octane number, from the viewpoint of preventing air pollution and saving gasoline consumption, etc. When blended gasoline (hereinafter abbreviated as gas hole) or a gasoline tank is used, it has a drawback that the amount of gasoline permeation from the entire tank increases, and improvement of these drawbacks is desired. As a means for improving this, the polyethylene-nylon laminate has a problem of barrier properties against gas holes. In addition, a method in which nylon is mixed with polyethylene and melt-extruded at the same time to disperse nylon in a discontinuous thin layer in the polyethylene layer is insufficient in barrier properties against gas holes, and the polyethylene single layer is subjected to sulfone treatment or fluorine treatment. In the method, there is a problem that the barrier property to the gas hole is insufficient and the permeability increases due to the water content in gasoline. Furthermore, in the case of a multi-layer tank or pipe of polyethylene and an ethylene-vinyl alcohol copolymer (hereinafter abbreviated as EVOH), the barrier property against gasoline and gas holes is excellent, but depending on the shape and the configuration,
Insufficient impact resistance.

Therefore, the object of the present invention is to improve the impact resistance without lowering the barrier property, and particularly for the fuel container or the fuel pipe, not only gasoline,
It is to impart sufficient permeation-preventing performance to gas holes as well as impact resistance.

[0005]

Means for Solving the Problems The above-mentioned object is ethylene-
It comprises a vinyl alcohol copolymer (a), an ethylene-acrylic acid ester-maleic anhydride copolymer and a thermoplastic resin (c) other than the above-mentioned (a) and (b), and the weight ratio of each component is (I) ) And (II) are provided. 5/95 ≦ [(b) + (c)] / (a) ≦ 50/50 ... (I) 10/90 ≦ (b) / (c) ≦ 90/10 (II) The object is achieved by providing a multilayer structure having a resin composition layer in which (c) is mixed with (a) and (b). This multilayer structure exhibits excellent barrier properties and impact resistance. Here, the barrier property means a gas barrier property such as oxygen, a fuel barrier property such as gasoline,
It means a barrier property against CFCs.

According to the present invention, it is possible to impart characteristics that are excellent in barrier properties against gasoline and gas holes and are excellent in impact resistance. This not only meets environmental problems, but also greatly enhances safety during actual use.

In the present invention, EVOH is ethylene-
It is a saponified product of vinyl ester copolymer, and the ethylene content is preferably 20 to 80 mol%, more preferably 20 to 7 mol%.
The amount of saponification of the vinyl ester component is preferably 80% or more, more preferably 85% or more, most preferably 90% or more. If the ethylene content is less than 20 mol%, the melt moldability is poor and the barrier properties and heat stability are poor. A typical vinyl ester is vinyl acetate, but other fatty acid vinyl esters (vinyl propionate, vinyl pivalate, etc.) can also be used. Further, vinyl silane compound 0.0002-
When 0.2 mol% is contained, the consistency of melt viscosity with the base resin at the time of co-extrusion is improved, not only a homogeneous co-extrusion multilayer film can be produced, but EVOHs are used for blending. The dispersibility at the time of carrying out is improved, and it is effective in improving the moldability. Here, examples of the vinylsilane-based compound include vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltri (β-methoxy-
Examples include ethoxy) silane and γ-methacryloxypropylmethoxysilane. Of these, vinyltrimethoxysilane and vinyltriethoxysilane are preferably used. Further, other comonomer [eg, propylene, butylene, unsaturated carboxylic acid or its ester {(meth) acrylic acid, (meth) acrylic acid ester methyl, ethyl), etc., as long as the object of the present invention is not impaired. }, Vinylpyrrolidone (such as N-vinylpyrrolidone)] can also be copolymerized. In addition, a suitable melt index (MI) of EVOH used in the present invention (210 ° C., 2160).
Value measured under g load; melting point around 210 ° C or 2
Those exceeding 10 ° C were measured under a load of 2160 g at a plurality of temperatures equal to or higher than the melting point, and in a semilogarithmic graph, the reciprocal of absolute temperature was plotted on the abscissa and the melt index (logarithm) was plotted on the ordinate, and extrapolated to 210 ° C. Value) is 0.1 to 50 g / 10
Min, optimally 0.5 to 20 g / 10 min. In the present invention, EVOH may be more preferably blended with one or more kinds of EVOH having different ethylene contents and / or saponification degrees. Also, EVOH
Has a melting point of 125 ° C to 220 ° C, preferably 130 to 220
C, optimally 135 to 220 C is desirable.
Here, the melting point can be determined by a differential thermal analysis (DSC) method (scanning speed 10 ° C./min).

In the present invention, an ethylene-acrylic acid ester-maleic anhydride copolymer (hereinafter referred to as E-EA-MA
The composition ratio of each component is not particularly limited as (b). However, the ethylene component is 10 to 97% by weight, the acrylic ester component is 1 to 50% by weight, and the maleic anhydride component is 1 to 50%. Weight percent is preferred. More preferably, it is selected from the range of 25 to 95% by weight of ethylene component, 2 to 45% by weight of acrylic acid ester component, and 1 to 30% by weight of maleic anhydride component. The melt index is also not particularly limited, but is 0.5 to 100 g.
/ 10 minutes (210 ° C., under a load of 2160 g) is suitable. Examples of the acrylate component include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate and the like.

In the present invention, the thermoplastic resin (c) other than the ethylene-vinyl alcohol copolymer (a) and the ethylene-acrylic acid ester-maleic anhydride copolymer (b) is a polyolefin resin, polystyrene. Examples thereof include polyamide resins, saturated polyester resins (polyethylene terephthalate, etc.), polycarbonate resins, polyvinyl chloride resins, polyvinylidene chloride resins, and the like, and polyolefins are particularly preferable.
By adding these components (c), cost reduction, stress crack resistance, adhesiveness, impact resistance and the like can be improved as required. Further, it is usually difficult to uniformly mix these components (c) with the ethylene-vinyl alcohol copolymer (a) due to poor compatibility, and it is difficult to obtain an excellent molded product. Then, even if the component (c) is blended, a molded article having excellent impact resistance and excellent barrier properties can be obtained. This is clear from the examples described later.

The polyolefin resin used as the component (c) in the present invention is mainly selected from high density or low density polyethylene, polypropylene, polybutene-1, etc., and ethylene, propylene, butene-1, hexene-1, etc. It is a copolymer of α-olefins with each other, but as a copolymerization component with these α-olefins, diolefin, N-vinylcarbazole, vinyl chloride, vinylidene chloride, vinyl acetate, styrene, acrylonitrile, vinyl ether, etc. Unsaturated carboxylic acids such as vinyl compounds, maleic acid, acrylic acid, methacrylic acid, ethacrylic acid, fumaric acid, and itaconic acid, their esters and their acid anhydrides, or those obtained by adding a hydroxyl group or an epoxy group to them. , Eg graftable A copolymer of a monomer and a polyolefin, or a copolymer of an α-olefin / α, β-unsaturated carboxylic acid copolymer and an ionic metal compound, such as an ionomer resin, containing 50% by weight or more of an α-olefin. Examples include polymers. These polyolefin-based resins may be used alone or in combination of two or more. Among these polyolefins, high density polyethylene, especially melt index (210 ° C, under 2160g load) 0.005-1
High-density polyethylene of g / 10 min, preferably 0.01 to 0.5 g / 10 min is suitable because it can impart impact resistance. Here, the high-density polyethylene is, for example, one obtained by a high pressure or medium pressure method using a Ziegler catalyst, and has a density of 0.941 to 0.965 g / c.
m ³ , preferably 0.945 to 0.96 g / cm ³ .

The polyamide resin used as the component (c) in the present invention is a polymer having an amide bond, and examples thereof include polycaproamide (nylon-6), polyundecaneamide (nylon-11), and polyundecaneamide. Homopolymers such as lauryllactam (nylon-12), polyhexamethyleneadipamide (nylon-6,6), polyhexamethylenesebacamide (nylon-6,12), caprolactam / lauryllactam copolymer (nylon) -6
/ 12), caprolactam / aminoundecanoic acid copolymer (nylon-6 / 11), caprolactam / ω-aminononanoic acid copolymer (nylon-6 / 9), caprolactam / hexamethylene diammonium adipate copolymer (nylon- 6/6, 6), caprolactam / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon-6 / 6, 6)
6/6, 12) and the like. These polyamide resins can be used alone or in combination of two or more.

The thermoplastic resin (c) is a mixture of two or more different kinds of resins, for example, polyolefin resin and polyamide resin, specifically nylon-6 and low density polyethylene, depending on the purpose. It can also be used.

Further, the resin composition of the present invention contains a hydrotalcite compound in order to enhance the effects of the present invention.
0.01 to 1% by weight of one or more of hindered phenol-based and hindered amine-based heat stabilizers and metal salts of higher aliphatic carboxylic acids (for example, calcium stearate, magnesium stearate, etc.) with respect to the resin composition. It is preferable to do It is also effective to enhance the effects of the present invention by adding alkali metal ions such as lithium ions, sodium ions and potassium ions to EVOH (a) in an amount of 5 to 5000 ppm, preferably 10 to 500 ppm. Examples of the alkali metal compound include monovalent metal aliphatic carboxylates, aromatic carboxylates, phosphates, metal complexes and the like, and specifically, sodium acetate, potassium acetate, sodium phosphate,
Examples thereof include lithium phosphate, sodium stearate, potassium stearate, and sodium ethylenediaminetetraacetic acid salt, with sodium acetate, potassium acetate, sodium phosphate, lithium phosphate, sodium stearate, and potassium stearate being preferred.

If necessary, additives may be added to the resin composition of the present invention. Examples of such additives may include antioxidants, plasticizers, heat stabilizers, UV absorbers, antistatic agents, lubricants, colorants, fillers, or other polymeric compounds. It can be blended within the range in which the effects of the present invention are not impaired. The following are specific examples of the additive. Antioxidant: 2,5-di-t-butylhydroxine,
2,6-di-t-butyl-p-cresol, 4,4'-
Thiobis- (6-tert-butylphenol), 2,
2'-methylene-bis- (4-methyl-6-tert-
Butylphenol), octadecyl-3- (3 ', 5'
-Di-tert-butyl-4'-hydroxyphenyl)
Propionate, 4,4'-thiobis- (6-tert
-Butylphenol) and the like. UV absorber: ethylene-2-cyano-3,3'-diphenyl acrylate, 2- (2'-hydroxy-5'-
Methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-methylphenyl)
Benzotriazole, 2- (2'-hydroxy-3'-
tert-butyl-5'-methylphenyl) 5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone and the like. Plasticizer: dimethyl phthalate, diethyl phthalate, dioctyl phthalate, wax, liquid paraffin, phosphate ester, etc. Antistatic agent: pentaerythritol monostearate, sorbitan monopalmitate, sulfated polyolefins,
Polyethylene oxide, carbowax, etc. Lubricants: ethylene bis stearamide, butyl stearate, etc. Coloring agent: carbon black, phthalocyanine, quinacridone, indoline, azo pigment, red iron oxide, etc. Filler: glass fiber, asbestos, ballastonite, calcium silicate, etc. Also, many other polymer compounds can be blended to the extent that the effects of the present invention are not impaired.

The composition ratios of the components (a), (b) and (c) in the present invention are as follows (I) and (II).
Is important, and preferably the following formulas (I ') and (II') are satisfied. 5/95 ≦ [(b) + (c)] / (a) ≦ 50/55 (I) Preferably, 10/90 ≦ [(b) + (c)] / (a) ≦ 45 / 55 (I ') 10/90 ≦ (b) / (c) ≦ 90/10 (II) Preferably, 30/70 ≦ (b) / (c) ≦ 70/30 .. (II ')

In the present invention, the multilayer structure means (a),
At least one resin composition layer comprising (b) and (c) is included, and a thermoplastic resin layer is laminated thereon. In this case, a scrap recovery layer and an adhesive resin layer can be provided as needed. When the resin composition layer of the present invention is (B), the thermoplastic resin layer is (H), the scrap recovery layer (R), and the adhesive resin layer (A), a multilayer structure having the following layer structure is obtained. As a representative example.

2 layers H / B 3 layers H / A / B, R / A / B, H / B / R, H
/ B / H 4 layers H / R / A / B, H / R / B / H, H / R /
B / R 5 layer H / R / A / B / H, H / R / A / B / R,
H / R / B / A / H H / A / B / A / H, H / R / B / R / H 6 layers H / R / A / B / A / H, H / R / A / B / A
/ R 7 layer H / R / A / B / A / R / H However, the layer structure is not limited to the above.

Examples of the thermoplastic resin used for the thermoplastic resin layer (H) include the above-mentioned thermoplastic resin (c), and also EVOH (a). Of these, the above-mentioned high-density polyethylene is suitable because it can impart excellent impact resistance. The adhesive resin used in the adhesive resin layer (A) is not particularly limited, but may be a polyurethane-based or polyester-based one-component or two-component curable adhesive, unsaturated carboxylic acid or The anhydride (maleic anhydride, etc.) of the olefin polymer or copolymer [polyethylene {low density polyethylene (LDPE), linear low density polyethylene (LL
DPE), ultra low density polyethylene (SLDPE)}, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid ester (methyl ester or ethyl ester) copolymer] are preferably used. .

Further, as the recovered material of the scrap recovery layer (R), the multilayer container of the present invention is used to form a molded product such as a hollow container, a tubular container, and a packaging container obtained by further processing the tubular body. There is a molding loss part in the case of doing, a crushed product of scrap collection products after being used by general consumers, and the like. The method for obtaining the multilayer structure of the present invention is not particularly limited, but for example, a molding method carried out in the field of general polyelefins, for example, T die molding,
Inflation molding, blow molding, stamping molding, blow molding, stretch blow molding, axial blow molding, injection molding and the like are mentioned, and coextrusion molding and coinjection molding are particularly suitable, but extrusion coating molding, dry lamination molding. Can also be adopted. Among these, the coextrusion sheet molding method, the coextrusion pipe molding method, the coextrusion molding method, the coextrusion blow molding method and the like are preferable, and the coextrusion blow molding method is particularly preferable.

Also, the thickness constitution of the multilayer structure is not particularly limited, but in consideration of moldability and cost, the ratio of the thickness of the layer comprising the resin composition according to the present invention to the total thickness (total thickness) (For layer thickness) is
About 1 to 30% is preferable. The structure having the resin composition layer of the present invention, in particular, the above-mentioned multilayer structure has excellent impact resistance, and further has excellent barrier properties against various fuels and gas barrier properties, and thus is particularly useful as various fuel containers and fuel pipes. It is valid. This is clear from the examples described later.

Here, the fuel container means a fuel container mounted on an automobile, a motorcycle, a ship, an aircraft, a generator and industrial or agricultural equipment, or a portable container for refueling these fuel containers. Further, it means a container for storing the fuel used for these operations. The fuel pipe is the fuel container mounted above, or
It means a portable container for supplying fuel to these fuel containers, a pipe attached to a container for storing the fuel used for these operations, or a pipe independent of itself. Typical examples of the fuel include gasoline, gasoline blended with methanol and / or MTBE, and other heavy oil, petroleum, and the like. Structures using the resin composition of the present invention, especially multilayer structures, other applications, for example, for various food,
It can also be used as a packaging container for cosmetics, pharmaceuticals, and medical products.

[0022]

The present invention will be further described with reference to the following examples. Example 1 EVOH containing 350 ppm of sodium acetate (about 98 ppm as sodium ions) (ethylene content 27 mol%, saponification degree 99.6%, melt index 2.0 g / 10 minutes (210 ° C., 2160 g load), melting point 190 ° C. )} (A) 70% by weight and ethylene (60% by weight) -ethyl acrylate (36% by weight) -maleic anhydride (4% by weight) terpolymer {MI = 6.1 g / 10
Min (210 ° C, 2160g load)} (b) 15% by weight
And high density polyethylene (density 0.96g / cm3, M
I = 0.20 g / 10 minutes (at 210 ° C., under a load of 2160 g) (c) After 15% by weight dry blending, 30
The mixture was melt-kneaded and pelletized using a mmφ twin-screw extruder. The pellets obtained here were used as a barrier layer, and high density polyethylene (HDPE) {MI = 0.17 g / 10
Min (210 ° C, 2160g load, density 0.96g / cm
3), “HZ8200B” manufactured by Mitsui Petrochemical Co., Ltd. is used as an outer layer, and further modified polyethylene {MI is used as an adhesive layer (AD).
= 1.0 g / 10 minutes (210 ° C., 2160 g load), using “Admer GT4” manufactured by Mitsui Petrochemical Co., Ltd., and co-extrusion blow molding, 3 types and 5 layers (HDPE / AD / barrier layer / A)
D / HDPE = 1169μ / 50μ / 60μ / 50μ /
1169 μ) of a 500 cc multilayer container was obtained. Also, using the same material as above, using a co-extruder equipped with a T-type die, three types of five layers (HDPE / AD / barrier layer / AD /
HDPE = 100μ / 1 0 μ / 25μ / 10μ / 100
A multilayer sheet of μ) was obtained.

Examples 2-5 In Example 1, EVOH (a) and E-EA-MAn were used.
The mixing ratio of (b) was changed to the ratio shown in Table 1, and
A multilayer container and a sheet were obtained under the same conditions as in Example 1 except that the component (c) and the compounding ratio shown in 1 were added and the mixture was melt-kneaded.

Comparative Examples 1 to 3 In Example 1, the components (a), (b) and (c) are used.
A multilayer container and a sheet were obtained under the same conditions as in Example 1 except that the compounding ratio of the components was changed to the ratio shown in Table 2.

[0025]

[Table 1]

[0026]

[Table 2]

Resin PE: high-density polyethylene {density 0.96 g / cm ³ ,
MI = 0.20 g / 10 minutes (210 ° C., 2160 g load), Mitsui Petrochemical's “HZ5100B”}, PP: polypropylene {MI = 5 g / 10 minutes (210 ° C., 216)
0g load), "J109G" manufactured by Ube Industries, PA: 6-
Nylon {MI = 1g / 10min (210 ℃, 2160g
Load), Toray's "CM1046-X04"}, IO: ionomer {MI = 9.9 g / 10 minutes (210 ° C, 21
60g load), "High Milan 165 made by Mitsui DuPont
2 "}, PET: polyester elastomer {MI = 1
5g / 10 minutes (210 ° C, 2160g load), Toyobo "P40H"}

The test and measurement were carried out by the following methods. Barrier property test 3 types 5 layers {HDPE (100
μ) / AD (10μ) / barrier layer (25μ) / AD
Model gasoline {toluene (42.5 wt%): isooctane (42.5 wt%): methanol (15 wt%) in a pouch (shape 12 × 20 cm) created using a multilayer sheet of (10 μ) / HDPE (100 μ)} %) And added with a volume of 110 ml}, and allowed to stand in an atmosphere of 20 ° C.-65% RH to determine the weight loss of the pouch after 2 weeks. (N = 5)

Bottle drop test 3 layers 5 layers obtained by coextrusion blow molding {HDPE (116
9μ) / AD (50μ) / barrier layer (60μ) / AD
(50μ) / HDPE (1169μ)} 500cc multi-layer container was filled with water and dropped onto concrete, and the drop height at which the bottle was broken was determined. (N = 20)

[0030]

The structure using the resin composition of the present invention, especially the multilayer structure, has superior impact resistance as compared with the case where EVOH (a) is used alone, and further, it is suitable for fuel such as gasoline. The barrier property is also comparable. Therefore, it is extremely effective for fuel tanks, fuel pipes, etc. of automobiles that require mechanical strength, particularly impact resistance, and also barrier properties.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08L 1/00-101/16 C08K 3/00-13/08 B32B 27/00-27/42

Claims (5)

(57) [Claims] 1. An ethylene-vinyl alcohol copolymer (a), an ethylene-acrylic acid ester-maleic anhydride terpolymer (b) , and a thermoplastic resin (c) other than the above-mentioned (a) and (b). And 5 to 5000 ppm relative to (a)
A resin composition containing an alkali metal ion and having a weight ratio of each component satisfying the following (I) and (II). 5/95 ≦ [(b) + (c)] / (a) ≦ 50/50 (I) 10/90 ≦ (b) / (c) ≦ 90/10 (II) 2. The resin composition according to claim 1, wherein the thermoplastic resin (c) is at least one resin selected from polyolefin resins, polyamide resins and saturated polyester resins. 3. A multilayer structure having the resin composition layer according to claim 1 or 2. 4. The method for producing a multilayer structure according to claim 3, wherein the multilayer structure is formed by a coextrusion molding method. 5. The method for producing a multilayer structure according to claim 4, wherein the coextrusion molding method is a coextrusion blow molding method.