JP2001341244A - Fuel container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel container with excellent fuel barrier properties, crack resistance when static deformation is performed, long-term interlaminar adhesive properties, etc. SOLUTION: The fuel container consists of a laminated body in which an ethylene-vinyl acetate copolymer soponified product is used as an intermediate layer and thermoplastic resins are arranged on both outermost layers and the relation of ethylene content of the ethylene-vinyl acetate copolymer soponified product of the intermediate layer and ethyl alcohol content in the fuel to be filled is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel container using a laminate having a saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH) as an intermediate layer, and more particularly to a fuel barrier. The present invention relates to a fuel container having excellent crack resistance during static deformation, long-term interlayer adhesion, and the like.

[0002]

2. Description of the Related Art In general, EVOH is excellent in transparency, antistatic property, oil resistance, solvent resistance, gas barrier property, fragrance retention property and the like.
By laminating films of low-density polyethylene, polypropylene, nylon, polyester, etc. on the front and back surfaces of the VOH layer, drop strength, thermoforming while maintaining EVOH properties such as gas barrier properties, aroma retention properties, and food discoloration prevention properties The fact is that EVOH is used for various packaging applications by compensating for the drawbacks of EVOH such as water resistance and moisture resistance. And
Recently, it has been used not only for food packaging as described above, but also for containers such as bottles, tanks, and drums for transporting, storing, and storing fuels mainly composed of hydrocarbons.

[0003] For example, EVOH in polyethylene resin
A fuel tank (JP-A-6-218891) in which a layer in which a gas barrier resin such as a gas barrier resin is dispersed as a discontinuous phase is used as an intermediate layer, and a polyethylene resin is used for an inner and outer layer (JP-A-6-218891). A fuel tank containing at least one thermoplastic resin selected from polyester (JP-A-7-52333), a layer containing a plasticizer in EVOH, and a polyamide;
A fuel tank in which a thermoplastic resin layer such as polyolefin is laminated (JP-A-6-328634), a multilayer structure in which a polyolefin layer treated with a halogen compound or a sulfur compound and a resin layer containing EVOH or polyamide are laminated. JP-A-6-340033), EV
A fuel tank in which the outer layer thickness is larger than the inner layer thickness in a container having OH as an intermediate layer (Japanese Patent Laid-Open No. 9-29
No. 904) has been proposed.
A laminated structure comprising an EVOH layer and a resin composition layer in which EVOH is dispersed in a polyolefin resin (JP-A-9-109)
334).

[0004]

However, recently, in consideration of the global environment (prevention of air pollution) and economic efficiency, it has been studied to mix an oxygen element-containing compound such as alcohol with a fuel typified by gasoline. In the above-mentioned known technology, the evaluation using a fuel containing methyl alcohol has been performed. However, handling and safety, toxic,
In view of supply and the like, ethyl alcohol is desired to be used in the future rather than methyl alcohol, but this has not been sufficiently studied so far. Accordingly, the present inventors have conducted intensive studies on fuels containing ethyl alcohol, and have found that the fuel containing ethyl alcohol and various physical properties of the EVOH-based multilayer fuel container (barrier properties, crack resistance during static deformation, long term ) Showed a different behavior from that of the fuel containing methyl alcohol.

That is, an object of the present invention is to focus on the ethyl alcohol blending amount of a fuel typified by gasoline blended with ethyl alcohol and the ethylene content of EVOH, and to examine the barrier properties and static deformation of the fuel. An object of the present invention is to provide a fuel container which is excellent in crack resistance at the time of application, long-term interlayer adhesion, and the like.

[0006]

The inventor of the present invention has conducted intensive studies in order to achieve the above object, and as a result,
The present inventors have found that a fuel container comprising a laminate in which OH is used as an intermediate layer and a thermoplastic resin is laminated on both outermost layers and which satisfies the following formula (1) achieves the above object. The invention has been completed.

A ≦ −2E + 72 (1) where E ≦ 36 [where A is the ethyl alcohol content (unit: volume%) in the fuel to be charged, and E is the ethylene-vinyl acetate copolymer It represents the ethylene content (unit; mol%) of the saponified product, respectively. ]

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The fuel container of the present invention is characterized in that the intermediate layer is made of EVOH, the outermost layer is made of a laminate in which a thermoplastic resin is laminated, and the above-mentioned formula (1) is satisfied. When the condition is not satisfied, that is, A> −2
In the case of E + 72, sufficient barrier properties, crack resistance during static deformation, long-term interlayer adhesion, and the like cannot be obtained, so that the object of the present invention cannot be achieved. It is particularly preferable to satisfy the following expression (3).

A ≦ −1.5E + 54 (2) where E ≦ 3
6 A ≦ −E + 36 (3) where E ≦ 3
6 wherein A and E each have the same meaning as in formula (1) above. ]

The fuel container of the present invention is a fuel container suitable for gasoline containing ethyl alcohol as described above, and the amount of ethyl alcohol contained in such gasoline is not particularly limited. It is preferably from 26 to 26% by volume, more preferably from 1 to 26% by volume, and particularly preferably from 2 to 21% by volume.

The EVOH used in the fuel container of the present invention has an ethylene content of 10 to 36 mol% (further, 1 to 36 mol%).
0 to 34 mol%, especially 15 to 26 mol%). When the ethylene content is less than 10 mol%, the low-temperature impact resistance and the melt moldability tend to decrease, and conversely 3
If it exceeds 6 mol%, sufficient barrier properties against fuel cannot be obtained, which is not preferable. Further, the saponification degree of such EVOH is 95 mol% or more (furthermore, 99 mol% or more, particularly 9 mol% or more).
9.5 mol%). If the saponification degree is less than 95 mol%, a sufficient barrier property against fuel may not be obtained, which is not preferable.

Further, the melt flow rate (MFR) of this EVOH (210 ° C., load 2160 g) is 0.1.
1 to 20 g / 10 min (more preferably 1 to 10 g / 10 min, especially 2 to 6 g / 10 min). When the melt flow rate is smaller than the above range, the inside of the extruder during molding of the fuel container is reduced. Extrusion may be difficult due to a high torque state, and if it is larger than this range, the mechanical strength of the fuel container may be insufficient, which is not preferable.

The EVOH is obtained by saponifying an ethylene-vinyl acetate copolymer. The ethylene-vinyl acetate copolymer can be produced by any known polymerization method, for example, solution polymerization,
It is produced by suspension polymerization, emulsion polymerization, or the like, and saponification of an ethylene-vinyl acetate copolymer can also be performed by a known method.

In the present invention, a copolymerizable ethylenically unsaturated monomer may be copolymerized within a range that does not impair the effects of the present invention (about 10 mol% or less). Are olefins such as propylene, 1-butene and isobutene, acrylic acid, methacrylic acid, crotonic acid, (phthalic anhydride), maleic anhydride, and anhydrous anhydride.
Unsaturated acids such as itaconic acid or salts thereof, mono- or dialkyl esters having 1 to 18 carbon atoms, acrylamide, N-alkylacrylamide having 1 to 18 carbon atoms, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or Acrylamides such as salts thereof, acrylamidopropyldimethylamine or its salts or quaternary salts, methacrylamide, C-C18 N-alkylmethacrylamide, N, N
-Dimethylmethacrylamide, 2-methacrylamidopropanesulfonic acid or a salt thereof, methacrylamidopropyldimethylamine or a salt thereof or 4
Methacrylamides such as grade salts, N-vinylpyrrolidone,
N-vinylamides such as N-vinylformamide and N-vinylacetamide; vinyl cyanides such as acrylonitrile and methacrylonitrile; vinyl ethers such as alkyl vinyl ether having 1 to 18 carbon atoms, hydroxyalkyl vinyl ether and alkoxyalkyl vinyl ether; Vinyl, vinylidene chloride, vinyl fluoride,
Vinyl halides such as vinylidene fluoride and vinyl bromide, vinyl silanes such as trimethoxy vinyl silane, allyl acetate, allyl chloride, allyl alcohol, dimethyl allyl alcohol, trimethyl- (3-acrylamide-
3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropanesulfonic acid and the like. Further, post-modification such as urethanization, acetalization, cyanoethylation, etc. may be performed as long as the gist of the present invention is not impaired.

In the present invention, it is also preferable to include an alkali metal in the EVOH in that the resulting fuel container is further improved in crack resistance during static deformation, long-term interlayer adhesion, and the like. As the alkali metal, sodium and potassium are preferable, and in containing these metals, acetic acid, propionic acid, butyric acid,
It is preferably contained as a metal salt of an organic acid such as lauric acid, stearic acid, oleic acid, and behenic acid, or a metal salt of an inorganic acid such as sulfuric acid, sulfurous acid, carbonic acid, boric acid, and phosphoric acid. Salts, phosphates and hydrogen phosphates.

The content of the alkali metal is E
It is preferable to be 5 to 1000 ppm (more preferably 10 to 500 ppm, particularly 20 to 300 ppm) in terms of metal with respect to VOH, and if the content is less than 5 ppm,
It becomes difficult to obtain the content effect, and the resulting fuel container may have insufficient crack resistance during static deformation, long-term interlayer adhesion, and the like. In some cases, the thickness of the EVOH layer of the fuel container becomes uneven, and crack resistance during static deformation of the fuel container and long-term interlayer adhesion tend to decrease, which is not preferable. When two or more alkali metals are contained in the EVOH, the total amount is preferably within the above range.

In the present invention, it is also preferable to include an alkaline earth metal in the EVOH in that the long run formability of the EVOH is improved and the stability of the quality of the obtained fuel container is improved. As the metal, calcium and magnesium are preferable, and when these metals are contained, it is preferable to include them as metal salts of the above-mentioned acids, and it is preferable to use acetate, borate, phosphate, hydrogen phosphate. is there.

The content of the alkaline earth metal is 5 to 500 ppm (more preferably 50 to 400 ppm, particularly 100 to 300 pp) in terms of metal relative to EVOH.
m), and when the content is less than 5 ppm, it is difficult to obtain the effect of the content, and EV
In some cases, the effect of improving the long-run moldability of OH may be poor. On the other hand, if it exceeds 500 ppm, the thickness of the EVOH layer of the obtained fuel container may be non-uniform, and the resistance to static deformation of the fuel container may be reduced. Cracking properties, long-term interlayer adhesion, and the like tend to decrease, which is not preferable. In addition, EVOH
When two or more alkaline earth metals are contained in
It is preferable that the total is within the range of the above content.

The method for incorporating an alkali metal and / or an alkaline earth metal into EVOH is not particularly limited, and a) a porous precipitate of EVOH having a water content of 20 to 80% by weight is converted to an alkali (earth) A method of contacting with an aqueous solution of a metal compound to contain an alkali metal compound and then drying; b) a uniform solution of EVOH (a water / alcohol solution, etc.)
, An alkali (earth) metal compound, extruded into a coagulating solution in the form of a strand or a sheet, and then the obtained strand or sheet is cut into pellets and further dried, c) EVOH And the alkali (earth) metal compound are mixed at once and then melt-kneaded with an extruder or the like. D) In the production of EVOH,
Examples include a method of neutralizing the alkali (sodium hydroxide, potassium hydroxide, etc.) used in the saponification step with acetic acid, and adjusting the amount of by-produced sodium acetate, potassium acetate, etc. by washing with water. it can. In order to obtain the effects of the present invention more remarkably, the methods a), b) and d) which are excellent in dispersibility of alkali (earth) metal are preferable.

In the present invention, the EVOH may contain boron or a boron compound (hereinafter, also referred to as boron compound including boron), or the resulting fuel container may have a crack resistance during static deformation. And boron compounds such as boric acid or metal salts thereof, such as calcium borate, cobalt borate, zinc borate (zinc tetraborate, zinc metaborate). Etc.), potassium aluminum borate, ammonium borate (ammonium metaborate,
Ammonium tetraborate, ammonium pentaborate, ammonium octaborate, etc.), cadmium borate (cadmium orthoborate, cadmium tetraborate, etc.), potassium borate (potassium metaborate, potassium tetraborate, potassium pentaborate, Potassium hexaborate, potassium octaborate, etc.), silver borate (silver metaborate, silver tetraborate, etc.), copper borate (cupric borate, copper metaborate, copper tetraborate, etc.), boric acid Sodium (sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, sodium octaborate, etc.), lead borate (lead metaborate, lead hexaborate, etc.), boric acid Nickel (nickel orthoborate, nickel diborate, nickel tetraborate, nickel octaborate, etc.), barium borate (barium orthoborate, metaborate) Barium phosphate, barium diborate, barium tetraborate, etc.), bismuth borate, magnesium borate (magnesium orthoborate, magnesium diborate, magnesium metaborate, trimagnesium tetraborate, pentamagnesium tetraborate, etc.), Manganese borate (manganese borate, manganese metaborate, manganese tetraborate, etc.), lithium borate (lithium metaborate,
And other borate minerals such as borax, carnite, inyoite, goethite, syanite, Zeyberite and the like, and preferably borax, boric acid and the like. And sodium borate (sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, sodium octaborate, etc.).

The content of the boron compound is E
10 to 10,000 ppm in terms of boron with respect to VOH
(Furthermore, 20 to 5000 ppm, especially 50 to 2000 ppm
ppm), and such a content is 10 p
If it is less than pm, it becomes difficult to obtain the effect of containing it, and the resulting fuel container may have insufficient crack resistance during static deformation, long-term interlayer adhesion, and the like.
If it exceeds 0000 ppm, the EVO of the resulting fuel container
The thickness of the H layer may become non-uniform, and crack resistance during static deformation of the fuel container and long-term interlayer adhesion tend to decrease, which is not preferable. When two or more boron compounds are contained in the EVOH, the total amount is preferably within the above range.

The method for incorporating a boron compound into EVOH is not particularly limited, and the above-mentioned alkali (earth) is used.
A method for containing a metal compound can be mentioned, and particularly preferable methods are 1) EV having a water content of 20 to 80% by weight.
The amount of the boron compound in the aqueous solution of the boron compound is adjusted to 0.001 to 0.5 with respect to 100 parts by weight of the total amount of the water contained in the EVOH and the water contained in the aqueous solution of the boron compound. A method of contacting with an aqueous solution of a boron compound adjusted to be parts by weight to contain the boron compound, and further drying by combining fluidized drying and standing drying; 2) contacting EVOH with an aqueous solution of a boron compound After containing the boron compound, the water content is 0.001 to 0.001.
2% by weight and then contact with water 3) E
A method in which a VOH pellet is brought into contact with an aqueous solution of a boron compound to contain the boron compound, and then dried to a moisture content of 0.001 to 10% by weight, and the resulting EVOH pellet is melt-kneaded to form a pellet again. 4) After a boron compound is contained in a homogeneous solution of EVOH (a water / alcohol solution or the like), it is extruded into a coagulating solution in the form of a strand, and then the obtained strand is cut into pellets, followed by further drying. be able to.

Further, in the present invention, the above EVOH
Metal salts of acids (acetic acid, phosphoric acid, etc.) and their transition metals (zinc, etc.) as long as the object of the present invention is not impaired;
Saturated aliphatic amides (eg, stearic acid amide, etc.), unsaturated fatty acid amides (eg, oleic acid amide, etc.), bisfatty acid amides (eg, ethylenebisstearic acid amide, etc.), fatty acid metal salts (the above-mentioned alkali (earth) metal salts) ), Low molecular weight polyolefins (e.g.
Lubricants such as low molecular weight polyethylene of about 10,000 or low molecular weight polypropylene, etc., inorganic salts (eg, hydrotalcite, etc.), plasticizers (eg, aliphatic polyhydric alcohols such as ethylene glycol, glycerin, hexanediol, etc.), Antioxidants, ultraviolet absorbers, oxygen absorbers, nucleating agents, coloring agents, antistatic agents, surfactants, desiccants, antibacterial agents, antiblocking agents (such as talc particles), slip agents (such as amorphous silica) Etc.), fillers (eg, inorganic fillers, etc.), other resins (eg, polyolefins, polyamides, etc.), and other EVOHs (EVOHs having different ethylene content, saponification degree, MFR, etc.) may be blended.

The present invention is a fuel container comprising the above-obtained EVOH layer as an intermediate layer, and a thermoplastic resin layer disposed on both outermost layers. The thermoplastic resin used for both outermost layers is as follows. , Linear low density polyethylene, low density polyethylene, ultra low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene copolymer, ethylene-acrylate copolymer , Polypropylene, propylene-α-olefin (α having 4 to 20 carbon atoms)
-Olefin) Broadly defined polyolefin-based resins such as copolymers, homo- or copolymers of olefins such as polybutene and polypentene, or those obtained by graft-modifying homo- or copolymers of these olefins with unsaturated carboxylic acids or esters thereof , Polyester, polyamide, copolymerized polyamide, polyvinyl chloride, polyvinylidene chloride, acrylic resin, polystyrene, vinyl ester resin, polyester elastomer, polyurethane elastomer, chlorinated polyethylene, chlorinated polypropylene, aromatic or aliphatic polyketone, and more Examples thereof include polyalcohols obtained by reducing these, and other EVOHs, and high-density polyethylene (HDPE) is preferably used from the viewpoint of practicality such as moldability and strength of the fuel container. In the present invention, the above-mentioned various additives, modifiers, other resins, and the like may be added to such a thermoplastic resin as long as the object of the present invention is not impaired.

In manufacturing the fuel container of the present invention, that is, a fuel container having a layer structure of thermoplastic resin layer / EVOH layer / thermoplastic resin layer, EVOH and thermoplastic resin are molded by injection molding machine, direct blow molding. Machine (continuous,
Accumulator type), a method of directly obtaining the multilayer fuel container of the present invention by subjecting it to an injection blow molding machine or the like, a method of vacuum-forming a multilayer sheet obtained by co-extruding EVOH and a thermoplastic resin, A method of vacuum forming a laminated sheet obtained by coextruding and laminating an EVOH / thermoplastic resin on a film, and a method of vacuum forming a multilayer sheet obtained by dry laminating a thermoplastic resin film and an EVOH film using an adhesive. Blow molding methods such as direct blow and injection blow are preferably employed. For example, a parison obtained by co-extrusion of EVOH and a thermoplastic resin is sandwiched between molds and blown by blowing air to obtain the fuel container of the present invention.

In the present invention, the thermoplastic resin layer is used as both outermost layers, and when the EVOH layer is a and the thermoplastic resin layer is b, only the layer structure of b / a / b as described above is used. Not b / a / b / a / b etc., or at least a mixture of EVOH and thermoplastic resin (recycled scrap)
When the regrind layer composed of is R, b / R / a /
b, b / R / a / R / b, b / a / R / a / b, b / R
/ A / R / a / R / b, etc., and a layer structure of b / a / b, b / R / a / b, b / R / a / R / b is preferably employed. In addition, if necessary, the mixture used in the regrind layer and the adhesive resin described later can be blended in b of these layer constitutions. Further, in these laminates, an adhesive resin is used between the layers (particularly, both interfaces of a) as necessary.

As the adhesive resin, a carboxylic acid obtained by chemically bonding an unsaturated carboxylic acid or an anhydride thereof to an olefin polymer (the above-mentioned polyolefin resin in a broad sense) by an addition reaction, a graft reaction or the like is used. Examples include a modified olefin polymer containing a group,
Specifically, maleic anhydride graft-modified polyethylene, maleic anhydride graft-modified polypropylene, maleic anhydride graft-modified ethylene-propylene (block or random) copolymer, maleic anhydride graft-modified ethylene-ethyl acrylate copolymer, anhydride One or a mixture of two or more selected from maleic acid graft-modified ethylene-vinyl acetate copolymers is preferred. At this time, the amount of the unsaturated carboxylic acid or the anhydride thereof contained in the olefin-based polymer is 0.
001 to 3% by weight (more preferably 0.01 to 1% by weight, particularly 0.03 to 0.5% by weight). In some cases, the properties and impact resistance may be insufficient. On the other hand, when the content is too large, a crosslinking reaction may occur, and the moldability may deteriorate, which is not preferable. In addition, these acid-modified olefin-based polymers include a rubber / elastomer component such as EVOH of the present invention and other EVOH, polyisobutylene, and ethylene-propylene rubber;
Furthermore, it is also possible to blend other thermoplastic resins and the like. In particular, by blending an olefin polymer different from the parent olefin polymer of the acid-modified olefin polymer, the adhesiveness may be improved, which is useful.

Further, the thickness of each layer cannot be specified unconditionally depending on the use, container form, required physical properties, and the like. For example, when used for a fuel tank of an automobile, a is 3
0 to 500 μm (more preferably 50 to 400 μm, especially 80
３００300 μm), b is 100 to 10000 μm (further 200 to 5000 μm, especially 300 to 3000 μm)
And R is 100 to 10000 μm (and even 20 μm).
0 to 5000 μm, especially 300 to 3000 μm), and the adhesive resin layer has a thickness of 30 to 500 μm (more preferably 50 to 400 μm).
m, especially about 80 to 300 μm), and the entire thickness of the fuel container is 300 to 10000 μm (further 1000 to 1000 μm).
8000 μm, especially 2000 to 6000 μm). In particular, the a (EVOH layer) is located at a position of 20 to 60% (furthermore, 25 to 55%, particularly 30 to 45%) from the inside to the outside in the thickness direction, so that the fuel barrier property,
It is preferable because crack resistance during static deformation, long-term interlayer adhesion, and the like are further excellent.

The fuel container of the present invention thus obtained is excellent in fuel barrier properties, crack resistance during static deformation, long-term interlayer adhesion, etc., and is a fuel container containing ethyl alcohol. For example, fuel containers for automobile fuel such as gasoline, motorcycles, ships, aircraft, generators, and fuel containers mounted on industrial and agricultural equipment, portable containers for replenishing these fuels, and transport of these fuels -Useful as various containers such as storage bottles, tanks, drums, etc. Examples of the fuel include gasoline, heavy oil, light oil, kerosene, and other fuels.

[0030]

The present invention will be specifically described below with reference to examples. In the examples, “parts” and “%” are based on weight unless otherwise specified.

The measurement of the boron content in EVOH was performed by subjecting EVOH to alkali melting and quantifying boron by ICP emission spectroscopy. Further, regarding the measurement of the alkali (earth) metal content,
After the incineration of VOH, it was carried out by dissolving in an aqueous hydrochloric acid solution and quantifying the alkali (earth) metal by atomic absorption spectrometry.

Example 1 EVOH [ethylene content 23 mol%, saponification degree 99.
6 mol%, MFR 2.7 g / 10 min (210 ° C., load 2
160 g)] water / methanol (water / methanol = 70)
/ 30 mixture weight ratio) solution (60 ° C, EVOH concentration 40
%) Was extruded into a water tank maintained at 5 ° C. in the form of a strand and solidified, and then cut with a cutter to obtain a pellet-shaped (diameter 4 mm, length 4 mm) EVOH coagulated product. The mixture was poured into warm water at 30 ° C. and stirred for about 4 hours to obtain a porous precipitate having a water content of 50%.

Next, 100 parts of the obtained porous precipitate was put into 200 parts of a 0.14% aqueous solution of magnesium acetate, and the mixture was stirred at 30 ° C. for 5 hours.
A water-containing EVOH containing 70 ppm was obtained. Using the batch-type fluidized bed dryer, the water-containing EVOH obtained above was treated with
Drying was carried out for about 3 hours while flowing nitrogen gas at 5 ° C. to make the water content 20%, and then dried with nitrogen gas at 125 ° C. for about 18 hours using a batch-type ventilated box dryer. Was carried out to obtain EVOH [containing 180 ppm of magnesium] having a water content of 0.25%.

Next, the obtained EVOH and thermoplastic resin (high density polyethylene, “HB214” manufactured by Nippon Polychem Co., Ltd.)
R ") and an adhesive resin (maleic anhydride-modified linear low-density polyethylene," M572 "manufactured by Mitsubishi Chemical Corporation).
Seed 6-layer co-extrusion Multi-layer direct blow device
[Outside] A four-layer, six-layer fuel container composed of a laminate of a high-density polyethylene layer / regrind layer / adhesive resin layer / EVOH layer / adhesive resin layer / high-density polyethylene layer [inner] (capacity of about 40 liters) Tank: Obtained an oval type (a hot water bottle shape) with a major axis of 750 mm, a minor axis of 530 mm, and a height of 280 mm. The thickness of the laminate at the center of the container is 5 m.
m, the composition thickness ratio of [outside] high-density polyethylene layer / regrind layer / adhesive resin layer / EVOH layer / adhesive resin layer / high-density polyethylene layer [inside] is 15/45/3 /
4/3/30 (the position of the EVOH layer was about 33 to 37% from the inside to the outside in the thickness direction). However, for the regrind layer, a pulverized product of the same fuel container that had been formed in advance was used.

The obtained fuel container was filled with 30 liters of model gasoline (mixing volume ratio = 40/40/10) consisting of a mixed solvent of toluene, isooctane and ethyl alcohol, and the inlet was closed with a metal plate. , The container is 40
One day in an environmental test room set at ± 2 ° C, then -10 ±
After three months of standing in an environmental test room set at 2 ° C for three months, the fuel barrier properties, crack resistance during static deformation, and long-term interlayer adhesion were evaluated in the following manner. Was.

It should be noted that the content of ethyl alcohol in the fuel A =
10 (% by volume), ethylene content of EVOH E = 23
(Mol%), and 10 (A) ≦ −2 × 23 (E) +7
2 = 26 was achieved, thereby satisfying the expression (1) in the text.

(Fuel barrier property) The weight change of the fuel container before and after the standing test was measured, and the permeation amount (g / g) of the model gasoline was measured.
day) was calculated.

(Crack Resistance During Static Deformation) The fuel container after the standing test was cut in the direction perpendicular to the major axis and minor axis, and the EVOH layer of the intermediate layer in the cross section was observed with an optical microscope.
The evaluation was as follows. ○ −−− No cracks were observed △ −−− Slight cracks were found × −−− Many cracks were found

(Long-term interlaminar adhesion) A 15 cm long × 1.5 cm wide test piece was cut from the body of the fuel container before and after the standing test, and bonded at a temperature of 23 ° C. and a humidity of 50% RH. The interlayer peel strength between the conductive resin layer and the EVOH layer was measured, and the retention (%) of the interlayer peel strength was examined.

Example 2 In Example 1, the ethylene content was 26 mol%, the saponification degree was 99.7 mol%, and the MFR was 3.5 g / 10 min (210
Water at a moisture content of 0.degree. C. under a load of 2160 g).
25%, 120% of magnesium acetate as magnesium
80p as ppm and calcium acetate as calcium
pm-containing EVOH, and similarly a fuel tank,
Evaluation was performed similarly. However, magnesium acetate and calcium acetate in EVOH were blended by contacting a water-containing porous precipitate of EVOH with a mixed aqueous solution of magnesium acetate and calcium acetate, containing magnesium acetate and calcium acetate, and then drying. .

The obtained model gasoline filled in the fuel container is a mixed solvent of toluene, isooctane and ethyl alcohol (mixing volume ratio = 40/40/10),
Ethyl alcohol content A = 10 (% by volume) in fuel
The ethylene content of EVOH was E = 26 (mol%), and 10 (A) ≦ −2 × 26 (E) + 72 = 20, thereby satisfying the expression (1) in the text.

Example 3 In Example 1, EVOH [ethylene content: 27.5
Mol%, degree of saponification 99.6 mol%, MFR 4.0 g / 1
0 minutes (210 ° C, load 2160g), water content 0.25
%, Containing 140 ppm of sodium acetate as sodium], and a fuel tank was obtained in the same manner. However, as for sodium acetate in EVOH, the water-containing porous precipitate of EVOH was brought into contact with an aqueous solution of sodium acetate to contain sodium acetate, and then blended.

The obtained model gasoline filled in the fuel container is a mixed solvent of toluene, isooctane and ethyl alcohol (mixing volume ratio = 47.5 / 47.5 / 5), and the content of ethyl alcohol in the fuel is as follows. A = 5 (% by volume), the ethylene content of EVOH E = 27.5 (mol%), and 5 (A) ≦ −2 × 27.5 (E) + 72 =
17, which satisfies the expression (1) in the text.

Example 4 In Example 1, EVOH [ethylene content 29 mol%, saponification degree 99.7 mol%, MFR 3.2 g / 10 min (210 ° C., load 2160 g), water content 0.25%, A fuel tank was obtained in the same manner as described above, except that boric acid was contained as boron in an amount of 150 ppm. However, the boric acid in EVOH was blended by contacting a water-containing porous precipitate of EVOH with a mixed aqueous solution of boric acid, containing boric acid, and then drying.

The obtained model gasoline filled in the fuel container was a mixed solvent of toluene, isooctane and ethyl alcohol (mixing volume ratio = 47.5 / 47.5 / 5), and the content of ethyl alcohol in the fuel was A = 5 (% by volume), ethylene content of EVOH E = 29 (% by mole)
5 (A) ≦ −2 × 29 (E) + 72 = 14, thereby satisfying the expression (1) in the text.

Comparative Example 1 In Example 1, the ethylene content was 32 mol%, the saponification degree was 99.7 mol%, and the MFR was 3.2 g / 10 min (210
A fuel tank was obtained in the same manner as above except that EVOH having a load of 2160 g) was evaluated in the same manner.

The model gasoline filled in the obtained fuel container was a mixed solvent of toluene, isooctane and ethyl alcohol (mixing volume ratio = 40/40/10), and the ethyl alcohol content A in the fuel was 10 (Volume%), ethylene content of EVOH E = 32 (mol%)
10 (A)> − 2 × 32 (E) + 72 = 8, which deviated from the expression (1) in the text. Table 1 summarizes the evaluation results of the examples and comparative examples.

[Table 1] Fuel barrier properties Long-term interlayer adhesion during static deformation (transmittance; g / day) Crack resistance (retention rate:%) Example 1 0.04 99 ○ 20. 07 ○ 99〃30.09 ○ 98〃4 0.11 ○ 98 Comparative Example 1 0.22 × 92

[0049]

According to the fuel container of the present invention, the EVOH of the intermediate layer is used.
Since the ethylene content of the fuel and the content of ethyl alcohol in the fuel to be filled have a specific relationship, the barrier properties of fuel containing ethyl alcohol, crack resistance during static deformation, long-term interlayer adhesion, etc. In addition to fuel tanks for automobile gasoline, fuel containers used in motorcycles, ships, aircraft, generators, and industrial and agricultural equipment, portable containers for replenishing these fuels, It is useful as various containers such as bottles, tanks and drums for transporting, storing and storing these fuels.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/38 C08L 29/04 S C08L 29/04 B60K 15/02 Z F term (Reference) 3D038 CA00 CA22 CB00 CC20 4F100 AK01B AK01C AK05 AK63 AK69A AL07 BA03 BA05 BA06 BA10B BA10C BA13 BA25 CB00 GB16 JB16B JB16C JD02 JK06 JK14 JL11 YY00 4J002 BE021 BE031 DH046 DK006 EG026 EG036 GF01GG01GG

Claims (7)

[Claims] 1. A fuel container comprising a laminate in which a saponified ethylene-vinyl acetate copolymer is used as an intermediate layer, and a thermoplastic resin is laminated on both outermost layers, and which satisfies the following formula (1). . A ≦ −2E + 72 (1) where E ≦ 36 [where A is the ethyl alcohol content (unit: volume%) in the fuel to be charged, and E is the saponified ethylene-vinyl acetate copolymer. The ethylene content (unit: mol%) is shown. ] 2. The fuel container according to claim 1, wherein the content of the alkali metal in the saponified ethylene-vinyl acetate copolymer is 5 to 1000 ppm. 3. The fuel container according to claim 1, wherein the content of the alkaline earth metal in the saponified ethylene-vinyl acetate copolymer is 5 to 500 ppm. 4. The content of boron or boron compound in a saponified ethylene-vinyl acetate copolymer is 10 to 1000.
The fuel container according to claim 1, wherein the amount is 0 ppm. 5. A laminated structure of at least a thermoplastic resin layer / a regrind layer / adhesive resin layer / a saponified ethylene-vinyl acetate copolymer layer / adhesive resin layer / thermoplastic resin layer. The fuel container according to claim 1. 6. The fuel cell according to claim 1, wherein the saponified ethylene-vinyl acetate copolymer layer is located at a position of 20 to 60% from the inside to the outside in the thickness direction of the fuel container.
6. The fuel container according to any one of claims 5 to 5. 7. The fuel container according to claim 1, wherein the fuel container is an automobile fuel tank.