JP2002361806A - Fuel container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel container excellent in fuel barrier properties, crack resistance at the time of static deformation, long-term interlaminar bonding properties or the like. SOLUTION: The fuel container comprises a laminate wherein both outermost layers comprising a thermoplastic resin are laminated on both surfaces of an intermediate layer comprising a saponified ethylene/vinyl acetate copolymer. The laminate satisfies the formula (1): A<=-1.12E+44.90 [wherein, A is the content (unit; volume %) of methyl alcohol in fuel and E is the ethylene content (unit; mol %) of the saponified ethylene/vinyl acetate copolymer and E<=40.0].

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. Resistance, crack resistance during static deformation,
The present invention relates to a fuel container having excellent 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 and the like. By laminating thermoplastic resin layers such as polypropylene, nylon, polyester, etc., while maintaining the properties of EVOH such as gas barrier properties, aroma retention properties, and food discoloration prevention properties, drop strength, thermoformability,
The fact is that EVOH is used for various packaging applications by compensating for the drawbacks of EVOH such as moisture proofness. And recently, not only for food packaging as described above, but also for transport, storage and storage of fuels mainly composed of hydrocarbons such as gasoline,
It has been used as a container such as a tank or a drum.

[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. Although the above-mentioned known technology has been evaluated using a fuel containing methyl alcohol, the market is demanding a further improvement in barrier properties and the like.

That is, an object of the present invention is to provide a fuel container for gasoline and the like containing methyl alcohol, wherein the fuel has a barrier property, crack resistance during static deformation, and long-term interlayer adhesion. An object of the present invention is to provide an excellent fuel container.

[0006]

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

A ≦ −1.12E + 44.90 (1) where E ≦ 40.0 [where A is the methyl alcohol content (unit: volume%) in the fuel to be charged, and E is ethylene -Represents the ethylene content (unit: mol%) of the saponified vinyl acetate copolymer. ]

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The fuel container of the present invention is characterized in that the intermediate layer is made of EVOH, the outermost layers are made of a laminate in which a thermoplastic resin is laminated, and the above formula (1) is satisfied. When these conditions are not satisfied, that is, A> −
In the case of 1.12E + 44.90, sufficient barrier properties, crack resistance at the time of static deformation, long-term interlayer adhesion and the like cannot be obtained, and the object of the present invention cannot be achieved. It is preferable to satisfy the expression (2), particularly the following expression (3). That is, EVOH having an ethylene content satisfying the above formula (1) or formulas (2) and (3) may be used in accordance with the content of methyl alcohol contained in the fuel to be charged. .

A ≦ −1.12E + 42.66 (2) where E ≦ 38.0 A ≦ −1.12E + 40.42 (3) where E ≦ 36.0 [where A and E Are the same as in the above equation (1). ]

The fuel container of the present invention is a fuel container suitable for gasoline containing methyl alcohol as described above, and the amount of methyl alcohol contained in such gasoline is not particularly limited. .1 to 15% by volume
Is preferred, more preferably 0.1 to 10% by volume, and particularly preferably 0.1 to 10% by volume.
1-5% by volume is preferred.

[0011] EVOH used in the fuel container of the present invention
Is preferably 10 to 35.6 mol% (more preferably 15 to 31.1 mol%, particularly 15 to 26.6 mol%), and the ethylene content is less than 10 mol%. In such a case, the low-temperature impact resistance and the melt moldability tend to decrease. Conversely, if it exceeds 35.6 mol%, a sufficient barrier property against fuel cannot be obtained, which is not preferable. The EVOH preferably has a saponification degree of 95 mol% or more (more preferably, 99 mol% or more, particularly 99.5 mol%). If the saponification degree is less than 95 mol%, sufficient barrier properties against fuel are obtained. May not be obtained, which is not preferred.

Further, the melt flow rate (MFR) of this EVOH (210 ° C., load 2160 g) is 0.1.
It is preferably 1 to 20 g / 10 min (more preferably 1 to 10 g / 10 min, particularly 2 to 6 g / 10 min). When the melt flow rate is smaller than the above range, the inside of the extruder is used during molding of the fuel container. In some cases, the high torque state results in difficulty in extrusion, and when 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, and cyanoethylation may be performed as long as the gist of the present invention is not impaired.

In the present invention, the inclusion of an alkali metal in the EVOH is also preferred in that the resulting fuel container further improves crack resistance during static deformation, long-term interlayer adhesion, and the like. As such an alkali metal, sodium or potassium is preferable, and when these metals are contained, 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 is difficult to sufficiently obtain the content effect, and conversely, 10
If it exceeds 00 ppm, the EVOH of the resulting fuel container
The thickness of the layer may be non-uniform, and crack resistance during static deformation of the fuel container, long-term interlayer adhesion, and the like 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 from the viewpoint 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 similar metals, calcium and magnesium are preferable, and when these metals are contained, they are preferably contained as metal salts of the above acids, and are preferably acetates, borates, phosphates, hydrogen phosphates. It is.

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
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 uneven, and when the fuel container is statically deformed. Crack resistance, long-term interlayer adhesion and the like tend to decrease, which is not preferable. In addition, EV
When two or more alkaline earth metals are contained in OH, it is preferable that the total amount is within the above range.

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 (earth) metal compound, followed by drying; b) after the alkali (earth) metal compound is contained in a homogeneous EVOH solution (water / alcohol solution, etc.) A method of extruding a strand or sheet into a coagulating liquid, cutting the obtained strand or sheet into pellets, and subjecting them to further drying treatment; c) EVOH
And kneading with an extruder or the like after mixing together and an alkali (earth) metal compound. D) During the production of EVOH, the alkali (sodium hydroxide, potassium hydroxide, etc.) used in the saponification step , And the amount of by-produced sodium acetate, potassium acetate, etc. is adjusted by washing with water. 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, sometimes referred to as boron compound including boron), and may be used to prevent cracking during static deformation of the obtained fuel container. Such boron compounds are preferably boric acid or a metal salt thereof, for example, calcium borate, cobalt borate, zinc borate (zinc tetraborate, metaboric acid). Zinc, etc.), aluminum potassium 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, hexaborate Potassium, eight potassium borate), boric silver (metaborate, silver tetraborate, silver, etc.), copper borate (boric acid cupric metaborate, copper tetraborate copper),
Sodium borate (sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate,
Sodium hexaborate, sodium octaborate, etc.), lead borate (lead metaborate, lead hexaborate, etc.), nickel borate (nickel orthoborate, nickel diborate, nickel tetraborate, nickel octaborate, etc.) ), Barium borate (barium orthoborate, barium metaborate, barium diborate, barium tetraborate, etc.), bismuth borate, magnesium borate (magnesium orthoborate, magnesium diborate, magnesium metaborate, tetraborate) Trimagnesium, pentamagnesium tetraborate, etc.), manganese borate (manganese borate, manganese metaborate, manganese tetraborate, etc.), lithium borate (lithium metaborate, lithium tetraborate, lithium pentaborate, etc.) ), Borax, carnite, inyoite, stones,
Examples thereof include borate minerals such as suyanite and ziberite, and preferably borax, boric acid, and sodium borate (sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, hexaborate). Sodium octarate, etc.) are used.

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 content effect thereof,
On the other hand, if it exceeds 10000 ppm, the thickness of the EVOH layer of the obtained fuel container may become non-uniform, and crack resistance during static deformation of the fuel container, long-term interlayer adhesion, etc., will also be reduced. There is a tendency and it is not preferable. In addition, EVO
When two or more boron compounds are contained in H, the total amount thereof is preferably within the above range.

The method for incorporating a boron compound into EVOH is not particularly limited, and it can be carried out in the same manner as the above-mentioned method for containing an alkaline (earth) metal compound. The amount of the EVOH porous precipitate having a water content of 20 to 80% by weight is determined by adjusting the content of the boron compound in the aqueous boron compound solution to 100 parts by weight of the total amount of the water contained in the EVOH and the water contained in the aqueous boron compound solution. A boron compound solution by contacting with an aqueous solution of a boron compound adjusted to be 0.001 to 0.5 parts by weight, and further drying by combining fluidized drying and standing drying. 2) EVOH A method in which a boron compound is contained by contact with an aqueous solution of a boron compound, and then dried to a water content of 0.001 to 2% by weight and then contacted with water. 3) EVOH pellet After the door is brought into contact with an aqueous solution of boron compound is boron compound, water content 0.0
A method of melting and kneading EVOH pellets obtained by drying to 01 to 10% by weight to obtain pellets again 4) EVO
After the boron compound is contained in a homogeneous solution of H (water / alcohol solution, etc.), it is extruded into a coagulating solution in a strand form,
Next, the obtained strand is cut into pellets,
Further, a method of performing a drying treatment and the like can be given.

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 relates to a fuel container having the above-obtained EVOH layer as an intermediate layer and a thermoplastic resin layer disposed on both outermost layers, wherein the thermoplastic resin used for both outermost layers is Is a 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. High-density polyethylene (HDPE) is preferably used from the viewpoint of practicality such as moldability and strength of a fuel container.
In the present invention, the above-mentioned various additives to the extent that the object of the present invention is not impaired in the thermoplastic resin,
You may mix a modifier, another resin, etc.

In producing 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 the thermoplastic resin are mixed with an injection molding machine and a direct injection molding machine. In addition to the method of directly providing the multi-layer fuel container of the present invention by using a blow molding machine (continuous type, accumulator type), an injection blow molding machine, etc., EVO
A method of vacuum forming a multilayer sheet obtained by co-extrusion of H and a thermoplastic resin.
A method of vacuum forming a laminated sheet obtained by co-extruding and laminating a thermoplastic resin, a method of vacuum forming a multilayer sheet obtained by dry laminating a thermoplastic resin film and an EVOH film using an adhesive, and the like. Can be
Preferably, a blow molding method such as direct blow or injection blow is employed. For example, a parison obtained by co-extrusion of EVOH and a thermoplastic resin is sandwiched between molds and blown with air to obtain a 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. A multilayer structure having at least these layer structures is desirable. If necessary, the mixture used in the regrind layer and an adhesive resin described later can be added to b of these layer configurations. further,
In these laminates, an adhesive resin is used between the layers (particularly, both interfaces of a) as necessary.

Such an adhesive resin is obtained by chemically bonding an unsaturated carboxylic acid or an anhydride thereof to an olefin polymer (the above-mentioned olefin homopolymer or copolymer) by an addition reaction, a graft reaction or the like. Modified olefin-based polymers containing a carboxyl group can be mentioned. Specifically, maleic anhydride graft-modified polyethylene, maleic anhydride graft-modified polypropylene, maleic anhydride graft-modified ethylene-propylene (block or random) copolymer Suitable examples include one or a mixture of two or more selected from a polymer, a maleic anhydride graft-modified ethylene-ethyl acrylate copolymer, a maleic anhydride graft-modified ethylene-vinyl acetate copolymer, and the like. At this time, the amount of unsaturated carboxylic acid or its anhydride contained in the olefin polymer is
0.001 to 3% by weight (more preferably 0.01 to 1% by weight, particularly 0.03 to 0.5% by weight) is preferable. If the amount of modification in the modified olefin polymer is small, the interlayer adhesion is poor. In addition, the moldability and the impact resistance may be insufficient, and conversely, if the amount is too large, a crosslinking reaction may occur and the moldability may deteriorate, which is not preferable. These acid-modified olefin polymers also include
EVOH of the present invention and other EVOH, polyisobutylene,
It is also possible to blend rubber / elastomer components such as ethylene-propylene rubber, and other thermoplastic resins. 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 μm).
8000 μm, especially 2000 to 6000 μm). In particular, it is required that a (EVOH layer) is located at a position of 20 to 60% (more preferably 25 to 55%, particularly 30 to 45%) from the inside to the outside in the thickness direction, because of the barrier property of the fuel and the static deformation. Is preferred because it is more excellent in crack resistance and long-term interlayer adhesion.

The fuel container of the present invention thus obtained is
Excellent fuel barrier properties, crack resistance during static deformation, long-term interlayer adhesion, etc., and fuel containers containing methyl alcohol, such as fuel tanks for automobile gasoline, motorcycles, Various types of containers such as fuel containers mounted on ships, aircraft, generators, and industrial and agricultural equipment, portable containers for replenishing these fuels, and bottles, tanks, and drums for transport, storage, and storage of these fuels It is useful as a container. 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%.

The obtained EVOH, thermoplastic resin (high-density polyethylene, "HB214R" manufactured by Nippon Polychem) and adhesive resin (maleic anhydride-modified linear low-density polyethylene, "M572" manufactured by Mitsubishi Chemical Corporation) Is supplied to a four-type, six-layer co-extrusion multilayer direct blow apparatus, and the [outside] high-density polyethylene layer / regrind layer / adhesive resin layer /
Four types and six layers of a fuel container (capacity of about 4) composed of a laminate of an EVOH layer / adhesive resin layer / high-density polyethylene layer [inside]
0 liter tank: major axis 750mm, minor axis 530m
m, an oval shape having a height of 280 mm-a hot water bottle shape-). The thickness of the laminate at the center of the container was 5 mm,
[Outside] High-density polyethylene layer / Regrind layer / Adhesive resin layer / EVOH layer / Adhesive resin layer / High-density polyethylene layer [Inside] The composition thickness ratio is 15/45/3/4/3.
/ 30 (about 33 to 37% of the position of the EVOH layer 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.

Into the obtained fuel container, 30 gasoline (mixing volume ratio = 47.5 / 47.5 / 5) composed of a mixed solvent of toluene, isooctane and methyl alcohol was added.
After filling the liter and closing the inlet with a metal plate, leave the container in an environmental test room set at 40 ± 2 ° C. for one day and then in an environmental test room set at −10 ± 2 ° C. for one day. After three months of operation, the fuel barrier properties,
Crack resistance during static deformation and long-term interlayer adhesion were evaluated.

The methyl alcohol content (A) in the fuel at this time was 5 (% by volume), the ethylene content (E) of EVOH was 23 (mol%), and 5 (A) <-1. .
12 × 23 (E) + 44.90 = 19.14, thereby satisfying the expression (1) in the text.

(Fuel Barrier Property) The change in weight of the fuel container before and after the standing test was measured, and the permeation amount (g) of the model gasoline was measured.
/ Day) was calculated.

(Crack resistance at the time of static deformation) The fuel container after the standing test was cut in a direction perpendicular to the major axis and the minor axis.
The EVOH layer of the intermediate layer in the cross section was observed with an optical microscope and evaluated as follows.・ ・ ・: No cracks were observed. ・ ・ ・: Slight cracks were observed. ×: Many cracks were observed.

(Long-term interlaminar adhesion) A 15 cm long × 1.5 cm wide test piece was cut out from the body of the fuel container before and after the standing test, and the temperature was 23 ° C. and the humidity was 50% RH. The delamination strength between the adhesive resin layer and the EVOH layer was measured, and the retention (%) of the delamination 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 was a mixed solvent of toluene, isooctane and methyl alcohol (mixing volume ratio = 47.5 / 47.5 /
5), the methyl alcohol content (A) in the fuel is 5 (% by volume), and the ethylene content (E) in EVOH is 2
6 (mol%), 5 (A) <− 1.12 × 26 (E) +
44.90 = 15.78 was achieved, 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], a fuel container was obtained in the same manner, and the same evaluation was performed. 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 was a mixed solvent of toluene, isooctane and methyl alcohol (mixing volume ratio = 47.5 / 47.5 /
5), the ethyl alcohol content (A) in the fuel is 5 (vol%), and the ethylene content (E) of EVOH is 2
At 7.5 (mol%), 5 (A) <− 1.12 × 27.5
(E) + 44.90 = 14.10 was achieved, thereby satisfying 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 container 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 model gasoline filled in the obtained fuel container was a mixed solvent of toluene, isooctane and methyl alcohol (mixing volume ratio = 47.5 / 47.5 /
5), the methyl alcohol content (A) in the fuel is 5 (% by volume), and the ethylene content (E) in EVOH is 2
9 (mol%), 5 (A) <− 1.12 × 29 (E) +
44.90 = 12.42 was achieved, thereby satisfying the expression (1) in the text.

Example 5 A mixed solvent of toluene, isooctane and methyl alcohol was used as a model gasoline to be filled in the fuel container obtained in Example 2 (mixing volume ratio = 42.5 / 42.
The evaluation was performed in exactly the same manner except that 5/15) was used. The methyl alcohol content (A) in the fuel was 15 (% by volume).
And the ethylene content (E) of EVOH is 26 (mol%)
15 (A) <− 1.12 × 26 (E) +44.90
= 15.78, thereby satisfying the expression (1) in the text.

Comparative Example 1 In Example 1, the ethylene content was 26 mol%, the saponification degree was 99.7 mol%, and the MFR was 3.2 g / 10 min (210
A fuel container 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 methyl alcohol (mixing volume ratio = 37.5 / 37.5 / 2).
5), the methyl alcohol content (A) in the fuel is 25 (% by volume), the ethylene content (E) of EVOH is 26 (mol%), and 25 (A)> − 1.12 × 26
(E) + 44.90 = 15.78, which deviates from the expression (1) in the text.

Comparative Example 2 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 container was obtained in the same manner as above except that EVOH having a load of 2160 g) was evaluated in the same manner.

The obtained model gasoline filled in the fuel container is a mixed solvent of toluene, isooctane and methyl alcohol (mixing volume ratio = 45/45/10), and has a methyl alcohol content (A) in the fuel. ) Is 10 (% by volume), the ethylene content (E) of EVOH is 32 (mol%), and 10 (A)> − 1.12 × 32 (E) +4
4.90 = 9.06, which deviates 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 0.03１99 ○ 20. 05 ９９99 ７3 0.07 99 〃4 0.08 98 ５5 0.12 ９７97 Comparative Example 1 0.25 × 87 〃2 0.30 △ 89

[0053]

According to the fuel container of the present invention, the intermediate layer EVO
Since the ethylene content of H and the content of methyl alcohol in the fuel to be filled satisfy a specific relationship, the barrier properties of fuel containing methyl alcohol, crack resistance during static deformation, and long-term interlayer adhesion In addition to fuel tanks for automobiles such as gasoline, motorcycles, ships, aircraft, generators, fuel containers for industrial and agricultural equipment, and portable refills for these fuels container,
Further, they are useful as various containers such as bottles, tanks and drums for transporting, storing and storing these fuels.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/08 C08L 29/04 S 3/38 F02M 37/00 301J C08L 29/04 B65D 1/00 B F02M 37/00 301 B60K 15/02 Z (72) Inventor Kenji Ninomiya 4-84-1, Matsue, Kurashiki-shi, Okayama Prefecture Nippon Gosei Chemical Industry Co., Ltd. 4-8-1 Nippon Kasei Chemical Industry Co., Ltd. Mizushima Plant F-term (reference) 3D038 CA03 CA19 CA22 CC20 3E033 AA20 BA14 BA17 BA21 BA22 BA30 BB08 CA03 CA20 FA02 FA03 FA04 GA02 3E086 AD30 BA04 BA15 BB20 BB90 CA40 4F100 AK01BAK AK01D AK01G AK05B AK05C AK63G AK69A AL07G BA03 BA04 BA06 BA10B BA10C CB00 DA01 GB16 GB32 JB16B JB16C JD01 JL11 JL16D 4J002 BE021 DA097 DA116 D K008

Claims (7)

[Claims] 1. A fuel for use as a fuel, 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 the following formula (1) is satisfied. container. A ≦ −1.12E + 44.90 (1) where E ≦ 40.0 [where A is the methyl alcohol content (unit: volume%) in the fuel to be charged, and E is ethylene-vinyl acetate] The ethylene content (unit: mol%) of the saponified copolymer 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 (in terms of boron). 5. A thermoplastic resin layer / regrind layer / adhesive resin layer / ethylene-vinyl acetate copolymer saponified layer /
The fuel container according to any one of claims 1 to 4, wherein the fuel container has at least a laminated structure of an adhesive resin layer / a thermoplastic resin layer. 6. The fuel container 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. Fuel container. 7. The fuel container according to claim 1, wherein the fuel container is an automobile fuel tank.