JP4208974B2 - Fuel container - Google Patents

Description

【００５７】
【発明の効果】
本発明により、ガソリンとくにメタノール含有ガソリンやＭＴＢＥ含有ガソリン等の含酸素ガソリンに対する透過防止性能及び耐衝撃性に優れた燃料容器を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel container excellent in permeation prevention performance (gasoline barrier property) and impact resistance against oxygen-containing gasoline such as automobile fuel, particularly methanol-containing gasoline and methyl tertiary butyl ether (hereinafter abbreviated as MTBE) -containing gasoline.
[0002]
[Prior art]
As a plastic fuel tank, a single-layer type made of polyethylene is widely used, but has a drawback of having a relatively high gasoline permeability. On the other hand, gasoline barrier properties have been improved by applying sulfone treatment (Japanese Patent Publication No. 46-23914) or Freon treatment (Japanese Examined Publication No. 47-21877, Japanese Patent Publication No. 53-15862) to polyethylene tanks. The method of improving and the method of mixing the substance which has barrier properties, such as nylon, into polyethylene (Unexamined-Japanese-Patent No. 4-296331) are taken. Also proposed is a three-kind five-layer structure in which the tank has a multilayer structure, nylon is used for the barrier layer, and a high-density polyethylene layer is provided on both sides of the tank via an adhesive resin layer.
[0003]
On the other hand, from the viewpoints of tightening regulations on environmental pollution in recent years, air pollution prevention and gasoline consumption saving, methanol, ethanol, MTBE, etc. to improve gasoline octane number and reduce the amount of unburned hydrocarbons in exhaust gas. Gasoline blended with oxygen-containing compounds such as oxygen (hereinafter abbreviated as oxygen-containing gasoline) is used mainly in the United States.
[0004]
However, in the method of making a multilayer structure of polyethylene and nylon as described above, or the method of mixing nylon into polyethylene and simultaneously melt-extruding and dispersing nylon in a discontinuous thin layer in the polyethylene layer, etc., oxygen-containing gasoline There is a problem with the barrier property against. Moreover, the method of sulfone treatment or fluorine treatment on a polyethylene single layer has a problem of insufficient barrier properties against oxygen-containing gasoline.
[0005]
Under such circumstances, a multi-layer tank of polyethylene and ethylene-vinyl alcohol copolymer (hereinafter abbreviated as EVOH) has been proposed as a container having excellent gasoline barrier properties, and has better gasoline barrier properties than the above-mentioned various fuel containers. Can now get. However, the gasoline barrier property is not necessarily sufficient for further strengthening of environmental regulations in the future, and has a problem in impact resistance.
[0006]
In order to improve various problems of the fuel container having EVOH resin as an intermediate layer, blending polyolefin or polyamide with EVOH resin (JP-A-6-218891, JP-A-7-52333) has also been proposed. However, since the gasoline barrier property is greatly reduced and there is a problem in melt stability, the actual situation is that the problem has not been essentially solved.
[0007]
[Problems to be solved by the present invention]
In view of this situation, providing a fuel container with good gasoline barrier properties and excellent impact resistance has great significance. Therefore, the present invention uses a high-density polyethylene layer and an EVOH layer, and by studying the layer structure earnestly, the fuel container has excellent gasoline barrier properties, particularly oxygen-containing gasoline barrier properties, and also has excellent impact resistance. The purpose is to provide.
[0008]
[Means for Solving the Problems]
  The above object is to provide each layer that has a high-density polyethylene (a) layer on the inner and outer layers of the ethylene-vinyl alcohol copolymer (c) layer via an adhesive resin (b) layer, and is inside the (c) layer. The thickness ratio (I / O) where I is the sum of the thicknesses of the layers and (c) is the sum of the thicknesses of the layers outside the layer is O.1 / 99-45 / 55(C) The thickness ratio (A / B) when the layer thickness is A and the total thickness is B is achieved by providing a fuel container satisfying the following formula (1).
0.03 ≦ (A / B) ≦ 0.13 (1)
  Especially the thickness ratio (I / O)3 / 97-43 / 57, More preferably 10/90 to 43/57,The thickness ratio (A / B) is 0.10 or less,The ethylene-vinyl alcohol copolymer is more effectively achieved by having an ethylene content of 20 to 60 mol%, an overall thickness of 310 to 10,000 μm, and oxygen-containing gasoline.
[0009]
(C) The thickness ratio (I / O) is less than 50/50, where I is the total thickness of each layer inside the layer, and (c) the total thickness of each layer outside the layer is O. Thus, it is possible to impart a characteristic excellent in barrier properties against gasoline, particularly oxygen-containing gasoline, and excellent in impact resistance. This not only adapts to environmental problems, but also greatly enhances safety during actual use. Furthermore, since the gasoline barrier property is improved, even if the EVOH layer thinner than the conventional one is used, the same level of gasoline barrier property can be obtained, and the impact resistance can be improved and the cost can be reduced. . In addition, since the impact resistance is improved, even if the overall thickness of the fuel container is reduced, the same impact resistance as before can be obtained, and the weight of the container can be reduced and the cost can be reduced. It becomes.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The fuel container of the present invention has a basic structure having a high-density polyethylene (a) layer via an adhesive resin (b) layer on both sides of the EVOH (c) layer of the intermediate layer. c) The thickness ratio (I / O) is less than 50/50, where I is the total thickness of each layer inside the layer, and (c) the total thickness of each layer outside the layer is O. Very important. In other words, the EVOH (c) layer is disposed at a position closer to the inside than the entire thickness. Here, when a layer other than the (a) layer and the (b) layer is provided on a part of the inside or outside, the thickness is added to I and O. In addition, the thickness of each layer in this invention means the average thickness of the trunk | drum of a container.
[0011]
By disposing the EVOH (c) layer at such a position, gasoline barrier properties and impact resistance are improved as compared with the case where the EVOH (c) layer is disposed at the center with respect to the entire layer thickness. The effect of improving the gasoline barrier property is as shown in Example 1 of the present application and Comparative Examples 3, 4, and 5 of the present application, and the position of the EVOH (c) layer moves from the outermost layer to the innermost layer. Therefore, the gasoline barrier property is improved. In the case where the position of the EVOH (c) layer is arranged in the outermost layer (Comparative Example 5) and the case where it is arranged in the innermost layer (Comparative Example 3), (a), (b), (c Despite the use of the) layer, surprisingly, an improvement of more than 4 times in gasoline barrier properties is achieved. The case where the EVOH (c) layer, which has been conventionally used, is arranged at the center of the total thickness (Comparative Example 4) and the case where it is arranged at the position of (I / O) = (2/8) (Example) However, the improvement of the gasoline barrier property is about 1.5 times. The significance of obtaining such a great effect in a laminated structure formed by using substantially the same amount of the same material is extremely significant.
[0012]
The reason why the EVOH (c) layer is arranged at a position closer to the inside than the entire thickness is not necessarily clear as to why the gasoline barrier property, particularly the barrier property of oxygen-containing gasoline, is greatly improved. It is considered that the degree of swelling of the high-density polyolefin (a) layer or EVOH (c) layer by each component such as MTBE is influenced by the position of the EVOH (c) layer. .
[0013]
Further, the impact resistance of the fuel container can be improved by arranging the EVOH (c) layer on the inner side with respect to the entire thickness. That is, when the EVOH (c) layer is arranged at the center of the entire thickness (Comparative Example 4), the fracture height in the drop test is 5.7 m, whereas (I / O) = (2/8) (Example 1) is improved to 7.6 m. It is considered that the impact resistance is improved by arranging a thicker HDPE layer on the outer side. As will be described later, although the impact resistance is improved as the installation position is moved from the center to the inside, it may be deteriorated if it is too close to the inside.
[0014]
As described above, the EVOH (c) layer is arranged at a position closer to the inner side than the entire thickness to improve the gasoline barrier property and impact resistance. However, the effect increases as the distance from the center increases. ) ≦ 45/55,More preferably, (I / O) ≦ 43/57,More preferably, (I / O) ≦ 40/60. In addition, it is particularly preferable that (I / O) ≦ 35/65, and (I / O) ≦ 30/70 is optimal.
[0015]
On the other hand, the multilayer container of the present invention has a high-density polyethylene (a) layer via an adhesive resin (b) layer on the inner and outer layers of the EVOH (c) layer, so that the EVOH (c) layer has an overall thickness. On the other hand, it is necessary to arrange it at a position closer to the inside, but it must not be arranged at the position of the innermost layer. The most common method for forming a fuel container is extrusion blow molding. At this time, the cylindrical molten parison must be cut and bonded with a mold, with the innermost layers contacting each other. The cylindrical opening is closed by bonding. When the adhesive strength of the closed portion (referred to as a pinch-off portion) is lowered, the impact resistance of the entire fuel container is lowered. Therefore, it is necessary to arrange the high-density polyethylene (a) layer and the adhesive resin layer (b) in the innermost layer.
[0016]
That is, (I / O) ≧ 1/99 is preferable, (I / O) ≧ 2/98 is more preferable,(I / O) ≧ 3/97 is more preferable,(I / O) ≧ 5/95 is particularly preferable, and (I / O) ≧ 10/90 is optimal.
[0017]
Further, when the thickness of the EVOH (c) layer is A and the total thickness is B, the thickness ratio (A / B) satisfies the following formula (1), so that a greater effect can be obtained.
0.03≦ (A / B) ≦ 0.13 (1)
When (A / B) is less than 0.005, not only the thickness of the EVOH (c) layer, which is a barrier layer, is small, but also a portion where the EVOH layer becomes extremely thin due to uneven film thickness of the (c) layer is generated. Therefore, the gasoline barrier property is not enough.oneWhen the direction (A / B) is 0.13 or more, the impact resistance deteriorates as the EVOH layer increases. Further, a large amount of expensive EVOH resin is used, which increases the cost. The value of (A / B) is preferably 0.10 or less, more preferably 0.07 or less.
[0018]
  In the present invention, EVOH is obtained by saponifying an ethylene-vinyl ester copolymer, and the ethylene content is from 20 to60Mole% is preferred. If the ethylene content is less than 20 mol%, the melt moldability is poor, and the gasoline barrier property under high humidity may be deteriorated. More preferably, it is 25 mol% or more, and optimally 30 mol% or more. On the other hand, ethylene content60If it exceeds mol%, the gasoline barrier properties deteriorate. More preferably, it is 50 mol% or less, More preferably, it is 40 mol% or less.
[0019]
A typical vinyl ester is vinyl acetate, but other fatty acid vinyl esters (such as vinyl propionate and vinyl pivalate) can also be used.
[0020]
Moreover, a copolymerization component may be included in EVOH as long as the gist of the present invention is not impaired. The copolymerization component is not particularly limited, but when it contains 0.0002 to 0.2 mol% of the vinylsilane compound, the consistency of the melt viscosity with the base resin at the time of coextrusion is improved, and it is homogeneous Not only is it possible to produce a coextruded multilayer film, but the dispersibility when using EVOHs in a blend is improved, which is effective in improving moldability and the like. Here, examples of the vinylsilane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxyethoxy) silane, and 3- (trimethoxysilyl) propyl methacrylate. Of these, vinyltrimethoxysilane and vinyltriethoxysilane are preferably used. In addition, other comonomer [eg, propylene, butylene, unsaturated carboxylic acid or ester thereof {(meth) acrylic acid, (meth) acrylic acid ester)}, vinylpyrrolidone (N-vinylpyrrolidone, etc.)] It can also be copolymerized.
[0021]
A suitable melt index (MI) of EVOH used in the present invention (measured at 190 ° C. under a load of 2160 g; those having a melting point near 190 ° C. or exceeding 190 ° C. are measured at a plurality of temperatures above the melting point under a load of 2160 g. In a semilogarithmic graph, the reciprocal of absolute temperature is plotted on the horizontal axis and MI (logarithm) is plotted on the vertical axis, and the value extrapolated to 190 ° C. is 0.1 to 50 g / 10 min. 20 g / 10 min.
[0022]
In the present invention, EVOH may be more preferably used by blending one or more EVOHs having different ethylene contents and / or saponification degrees.
[0023]
In the present invention, the EVOH (c) layer is originally a layer composed of an EVOH resin alone, but other resins can be blended within a range not impairing the gist of the present invention. Examples of other resins include polyolefin resins, polystyrene, polyamide resins, saturated polyester resins (polyethylene terephthalate, etc.), polycarbonate resins, polyvinyl chloride resins, polyvinylidene chloride resins, and the like. At least one functional group selected from an acrylic ester-maleic anhydride terpolymer, a boronic acid group, a borinic acid group, and a boron-containing group that can be converted to a boronic acid group or a borinic acid group in the presence of water. Suitable modified polyolefins such as polyolefins are included. However, it is only possible to add a small amount in consideration of gasoline barrier properties and melt stability which are lowered by blending.
[0024]
In the present invention, the high density polyethylene (a) is obtained by a low pressure method or an intermediate pressure method using, for example, a Ziegler catalyst, and has a density of 0.93 g / cm.^ThreeOr more, preferably 0.94 g / cm^ThreeThe above is shown. Polyethylene having a density of less than 0.93 lacks gasoline barrier properties and rigidity, and cannot be used as a fuel tank. Moreover, suitable MI (a value measured under a load of 2160 g at 190 ° C.) of the high density polyethylene is 0.001 to 0.6 g / 10 minutes, preferably 0.005 to 0.1 g / 10 minutes.
[0025]
Moreover, you may mix | blend other resin etc. with the high density polyethylene (a) layer in the range which does not inhibit the meaning of this invention. Examples of other resins include EVOH resins, other polyolefin resins, polystyrene, polyamide resins, saturated polyester resins (polyethylene terephthalate, etc.), polycarbonate resins, polyvinyl chloride resins, and polyvinylidene chloride resins. . However, it is preferable that the main component is high density polyethylene and is blended within a range that does not impair the gist of the present invention.
[0026]
Also, the scrap recovered at the time of molding can be used as a high-density polyethylene (a) layer if the main component is high-density polyethylene. Here, the scrap recovered product includes a molding loss portion generated when manufacturing a molded product such as a hollow container, a tubular container, and a tubular body, and a crushed product of the scrap recovered product after being used by general consumers. is there. Since the amount of waste is suppressed by using such scrap collection, it is preferable from the viewpoint of environmental conservation, and an effect of cost reduction is also obtained. In this case, the scrap recovered material alone can be used as a high density polyethylene (a) layer, or a mixture of scrap recovered material and high density polyethylene can be used as the high density polyethylene (a) layer. Moreover, the high density polyethylene (a) layer which consists of a multilayer structure of the layer which consists of a high density polyethylene independent, and the layer containing a scrap collection | recovery thing is also employable.
[0027]
The scrap recovered material is typically composed of high-density polyethylene as a main component and contains EVOH resin and adhesive resin, but in order to improve melt film-forming properties, the scrap recovered material component is a compatibilizing agent. Alternatively, a stabilizer may be added separately. Such compatibilizers and stabilizers include ethylene-acrylic acid ester-maleic anhydride terpolymers, or boronic acid groups, borinic acid groups, converted to boronic acid groups and borinic acid groups in the presence of water. Examples thereof include polyolefins having at least one functional group selected from boron-containing groups, metal salts of higher fatty acids, hydrotalcite, and the like.
[0028]
By laminating such a high-density polyethylene (a) layer on the inner and outer layers of the EVOH (c) layer via the adhesive resin (b) layer, as shown in the examples described later, the gasoline barrier property was excellent. In addition, a fuel tank and a fuel container excellent in impact resistance can be obtained. The high-density polyethylene (a) layer is preferably in the innermost layer and the outermost layer. However, other resin layers may be laminated on the innermost layer or the outermost layer as long as the object of the present invention is not hindered. It is. The thickness of the high density polyethylene (a) layer including the inner and outer layers is preferably 300 to 10000 μm, more preferably 500 to 8000 μm, and most preferably 1000 to 6000 μm.
[0029]
In addition, the adhesive resin used for the adhesive resin (b) layer is not particularly limited, and modified polyolefin resin, polyurethane resin, polyester one-component or two-component curable resin, etc. Can be used. Of these, a modified polyolefin resin is preferable from the viewpoint of adhesion to EVOH and high-density polyolefin resin and melt moldability, and a carboxylic acid-modified polyolefin resin is particularly preferable. Such a carboxylic acid-modified polyolefin resin can be obtained by copolymerizing an unsaturated carboxylic acid or its anhydride (such as maleic anhydride) into an olefin polymer or copolymer, or by graft modification.
[0030]
Furthermore, it is more preferable that the carboxylic acid-modified polyolefin resin is a carboxylic acid-modified polyethylene resin from the viewpoint of adhesion with a high-density polyethylene resin or compatibility during scrap recovery. Examples of such carboxylic acid-modified polyethylene resins include polyethylene {low density polyethylene (LDPE), linear low density polyethylene (LLDPE), very low density polyethylene (SLDPE)}, ethylene-vinyl acetate copolymer, ethylene- Examples thereof include those obtained by modifying a (meth) acrylic acid ester (methyl ester or ethyl ester) copolymer or the like with a carboxylic acid.
[0031]
By providing such an adhesive resin (b) layer between the high-density polyethylene (a) layer and the EVOH (c) layer, it has excellent in-layer adhesiveness, and has the barrier property and the object of the present invention. A fuel tank having excellent impact resistance can be obtained. In addition, as thickness of the adhesive resin (b) layer which added the some layer used, Preferably it is 5-1000 micrometers, More preferably, it is 10-500 micrometers, Optimally, 20-300 micrometers. When the film thickness of the adhesive resin layer is too small, the adhesiveness is lowered, and when it is too thick, the cost is increased.
[0032]
As described above, the high-density polyethylene (a) layer in the present invention includes the scrap collection layer (r) mainly composed of high-density polyethylene, and the high-density polyethylene in consideration of the scrap collection layer (r). Examples of the layer structure of the multilayer structure of the present invention including the (a) layer, the adhesive resin (b) layer, and the EVOH (c) layer include the following. In this illustration, the left is inside and the right is outside.
[0033]
5 layers (inside) a / b / c / b / a (outside), a / b / c / b / r, r / b / c / b / a
6 layers a / b / c / b / r / a, a / r / b / c / b / a, r / a / b / c / b / a, a / r / b / c / b / r, r / a / b / c / b / r, a / b / c / b / a / r, r / b / c / b / r / a, r / b / c / b / a / r
7 layers a / r / b / c / b / r / a, a / r / b / c / b / a / r, r / a / b / c / b / a / r, r / a / b / c / b / r / a, a / r / b / c / b / r / a, r / a / b / c / b / a / r
However, the layer structure is not limited to the above. Among these, preferable layer configurations include a / b / c / b / a, a / b / c / b / r / a, and the like.
[0034]
The total thickness of the fuel container is preferably 310 to 10,000 μm, more preferably 500 to 8500 μm, and most preferably 1000 to 7000 μm. In addition, these thickness says the average thickness in the trunk | drum of a fuel container. If the overall thickness is too large, the weight will be too large, which will adversely affect the fuel consumption of automobiles and the like, and the cost of the fuel container will also increase. On the other hand, if the total thickness is too small, the rigidity cannot be maintained, and there is a problem that it is easily destroyed. Therefore, it is important to set a thickness corresponding to the capacity and application.
[0035]
The method for obtaining the fuel container having the multilayer structure of the present invention is not particularly limited, but examples thereof include molding methods practiced in the general polyolefin field, such as extrusion molding, blow molding, injection molding, and the like. In particular, co-extrusion molding and co-injection molding are suitable. Of these, the coextrusion blow molding method is particularly optimal.
[0036]
In the present invention, the fuel container refers to a fuel container mounted on an automobile, motorcycle, ship, aircraft, generator and industrial and agricultural equipment, or a portable container for replenishing the fuel container, , And means a container for storing fuel used for these operations.
[0037]
As fuel, gasoline, especially gasoline blended with methanol, ethanol, MTBE, or the like, that is, oxygen-containing gasoline, is given as a representative example, but other heavy oil, light oil, kerosene, etc. are also exemplified. Among these, the effects of the present invention are obtained particularly for oxygen-containing gasoline.
[0038]
In the present invention, an additive may be added to the high-density polyethylene (a) layer, the adhesive resin (b) layer, and the EVOH (c) layer, which are components of the multilayer structure. Examples of such additives include antioxidants, plasticizers, heat stabilizers, ultraviolet absorbers, antistatic agents, lubricants, colorants, fillers, and the like. Specific examples of the additive include the following.
[0039]
Antioxidant: 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,4′-thiobis- (6-t-butylphenol), 2,2′-methylene -Bis- (4-methyl-6-tert-butylphenol), octadecyl-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate, 4,4'-thiobis- (6- t-butylphenol) and the like.
UV absorber: ethylene-2-cyano-3,3′-diphenyl acrylate, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) benzo Triazole, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) 5-chlorobenzotriazole, 2-hydroxy- 4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-oxybenzophenone and the like.
Plasticizer: dimethyl phthalate, diethyl phthalate, dioctyl phthalate, wax, liquid paraffin, phosphate ester, etc.
Antistatic agents: pentaerythritol monostearate, sorbitan monopalmitate, sulfated polyolefins, polyethylene oxide, carbowax and the like.
Lubricant: ethylene bisstearamide, butyl stearate, etc.
Colorant: Carbon black, phthalocyanine, quinacridone, indoline, azo pigment, Bengala, etc.
Filler: Glass fiber, asbestos, ballastite, calcium silicate, talc, montmorillonite, etc.
[0040]
EVOH (c) includes a hydrotalcite compound, a hindered phenol, a hindered amine heat stabilizer, and a metal salt of a higher fatty acid carboxylic acid (for example, calcium stearate, magnesium, etc.) as a measure for preventing gel formation. Alternatively, it is preferable to add two or more of 0.01 to 1% by weight.
[0041]
【Example】
  Hereinafter, the present invention will be described using examples and comparative examples. However, the present invention is not limited to these examples.Here, Examples 2 to 4 and 15 do not satisfy the requirements of the thickness ratio (A / B) of the present invention, and are described for reference. Examples of the present invention are only Examples 1 and 5-14.
[0042]
Example 1
EVOH {ethylene content 32 mol%, saponification degree 99.6%, MI = 3.0 g / 10 min (190 ° C., 2160 g load)} as an intermediate layer, high density polyethylene (HDPE) {MI = 0.01 g / 10 Minutes (190 ° C., 2160 g load), density 0.96 g / cm 3, Mitsui Petrochemical's “HZ8200B”} is used as an outer layer, and an adhesive resin (AD) layer is coated with maleic anhydride-modified polyethylene {MI = 0.2 g / 10 minutes (190 ° C., 2160 g load), “Admer GT4” manufactured by Mitsui Petrochemical Co., Ltd., and co-extrusion blow molding, 3 types 5 layers (inner layer HDPE / AD / EVOH / AD / outer layer HDPE = 435/50 / 75/50 / 1890μ) 500 cc multilayer container was obtained.
[0043]
Put 300 ml of model gasoline {mixture of toluene (42.5% by weight): isooctane (42.5% by weight): methanol (15% by weight)} into this multi-layer container, and completely stopper it to prevent leakage. The bottle was allowed to stand in an atmosphere of 20 ° C. and 65% RH, and the bottle weight reduction amount after 4 days (average value of n = 6) was determined. The amount of weight loss was 0.33 g.
[0044]
Next, the same multilayer container as above was filled with water and dropped onto the concrete, and the drop height at which the bottle was broken (water inside the container leaked) was determined. The fracture height was determined by using the test result of n = 30 and using the calculation method shown in the JIS test method (“8. Calculation” part of K7211) to determine the 50% fracture height. The breaking height was 7.5 m.
[0045]
Examples 2 to 15 and Comparative Examples 1 to 12
In Example 1, except that the thickness and configuration of each layer of the multilayer container were changed as shown in Table 1, a multilayer container was obtained under the same conditions as in Example 1, and a barrier test and a bottle drop test were performed. The results are summarized in Table 1.
[0046]
Example 16, Comparative Example 13
In the multilayer container prepared in Example 1 and Comparative Example 4, the ratio of the model gasoline used in Example 1 {toluene (42.5% by weight): isooctane (42.5% by weight): methanol (15% by weight) A barrier test was conducted in the same manner as in Example 1 except that model gasoline without methanol (a mixture having a ratio of toluene (50% by weight): isooctane (50% by weight)) was used instead of the mixture}. The weight loss amounts in Example 16 and Comparative Example 13 were 0.02 g and 0.03 g, respectively.
[0047]
Examples 17-20
A multilayer container was obtained under the same conditions as in Example 1 except that the EVOH used in Example 1 was changed to another EVOH having a different ethylene content, and a barrier test and a bottle drop test were performed. The ethylene content, weight loss, and fracture height in each example are as follows. Example 17 (ethylene content 27 mol%); 0.29 g, 7.2 m. Example 18 (ethylene content 38 mol%); 0.48 g, 7.6 m. Example 19 (ethylene content 44 mol%); 0.62 g, 7.6 m. Example 20 (ethylene content 51 mol%); 0.98 g, 7.8 m.
[0048]
Example 21
EVOH used in Example 1 was modified with 0.01 mol% trimethoxyvinylsilane EVOH {ethylene content 47 mol%, saponification degree 96.0%, MI = 5.0 g / 10 min (190 ° C, A multilayer container was obtained under the same conditions as in Example 1 except that the load was changed to 2160 g load)}, and a barrier test and a bottle drop test were performed. The weight loss was 0.73 g, and the breaking height was 7.7 m.
[0049]
Comparative Example 14
Instead of EVOH used in Example 1, EVOH {ethylene content 32 mol%, saponification degree 99.6%, MI = 3.0 g / 10 min (190 ° C., 2160 g load)} 10 wt% and linear low density Example except that 90% by weight of polyethylene (LLDPE) {MI = 2.1 g / 10 minutes (210 ° C., 2160 g load), Mitsui Petrochemical's “Ultzex 2022L”} was melt kneaded and pelletized resin was used. A multilayer container was obtained under the same conditions as in No. 1, and a barrier test and a bottle drop test were performed. The weight loss was 2.93 g, and the breaking height was 8.1 m.
[0050]
Comparative Example 15
Instead of EVOH used in Example 1, EVOH {ethylene content 32 mol%, saponification degree 99.6%, MI = 3.0 g / 10 min (190 ° C., 2160 g load)} 80 wt% and nylon 6 (PA -6) {MI = 7.2 g / 10 min (230 ° C., 2160 g load), “UBE Nylon 1022B”} manufactured by Ube Industries, Ltd. 20 wt% was kneaded and used in Example 1 except that a pelletized resin was used. A multilayer container was obtained under the same conditions, and a barrier test and a bottle drop test were performed. The weight loss was 1.04 g, and the breaking height was 7.9 m.
[0051]
Comparative Example 16
Instead of the HDPE (a) layer used in Example 1, linear low density polyethylene (LLDPE) {MI = 2.1 g / 10 min (210 ° C., 2160 g load), density 0.920 g / cm^ThreeA multi-layer container was obtained under the same conditions as in Example 1 except that Mitsui Petrochemical's “Ultzex 2022L”} was used, and a barrier test and a bottle drop test were performed. The weight loss was 1.26 g, and the breaking height was 7.5 m. Moreover, the multilayer container obtained in this way had low rigidity and was easily deformed by the load.
[0052]
Example 22
The adhesive resin (b) layer used in Example 1 was bonded to Bondin TX8030 {ethylene (60 wt%)-acrylic ester (36 wt%)-maleic anhydride (4 wt%) terpolymer, MI = 4. 0.0 g / 10 min (190 ° C., 2160 g load); manufactured by Atchem Corp.}, a multilayer container was obtained under the same conditions as in Example 1, and a barrier test and a bottle drop test were performed. The weight reduction amount was 0.38 g, and the breaking height was 7.3 m.
[0053]
Example 23
The adhesive resin (b) layer used in Example 1 was changed to EV270 {ethylene-vinyl acetate copolymer, MI = 4.0 g / 10 min (190 ° C., 2160 g load); manufactured by Mitsui DuPont Polychemical Co., Ltd.}. A multilayer container was obtained under the same conditions as in Example 1 except that a barrier test and a bottle drop test were performed. The weight reduction amount was 0.37 g, and the breaking height was 6.2 m.
[0054]
Example 24
In place of the inner HDPE (a) layer used in Example 1, the multilayer container of Example 1 was pulverized and a multilayer container was obtained under the same conditions as in Example 1 except that the re-pelletized resin was used. A barrier test and a bottle drop test were conducted. The weight reduction amount was 0.31 g, and the breaking height was 6.9 m.
[0055]
Example 25
Instead of the outer HDPE (a) layer used in Example 1, the resin layer obtained by pulverizing and re-pelletizing the multilayer container of Example 1 and the HDPE layer used in Example 1 at a thickness ratio of 1: 3 A multilayer container was obtained under the same conditions as in Example 1 except that the layers were arranged so as to be the outermost layer, and a barrier test and a bottle drop test were performed. The weight reduction amount was 0.32 g, and the breaking height was 6.5 m.
[0056]
[Table 1]

[0057]
【The invention's effect】
According to the present invention, it is possible to provide a fuel container excellent in permeation prevention performance and impact resistance against oxygen-containing gasoline such as gasoline, particularly methanol-containing gasoline and MTBE-containing gasoline.

Claims (6)

The inner and outer layers of the ethylene-vinyl alcohol copolymer (c) layer have a high-density polyethylene (a) layer through an adhesive resin (b) layer, and (c) the thickness of each layer inside the layer The thickness ratio (I / O) is 1/99 to 45/55 when the total is I and (c) the total thickness of each layer outside the layer is O. (c) The thickness of the layer is A And a fuel container in which the thickness ratio (A / B) when the total thickness is B satisfies the following formula (1).
0.03 ≦ (A / B) ≦ 0.13 (1) The fuel container according to claim 1, wherein the thickness ratio (I / O) is 3/97 to 43/57 . The fuel container according to claim 1, wherein the thickness ratio (I / O) is 10/90 to 43/57, and the thickness ratio (A / B) is 0.10 or less.   The fuel container according to any one of claims 1 to 3, wherein the ethylene content of the ethylene-vinyl alcohol copolymer is 20 to 60 mol%.   The fuel container according to any one of claims 1 to 4, wherein an overall thickness is 310 to 10,000 µm.   The fuel container according to any one of claims 1 to 5, which is used for oxygen-containing gasoline.