JP2004262451A - Fuel container excellent in gasoline barrier property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayered fuel container equipped with multilayered molded parts for the container excellent in a gasoline barrier property, a heat fusing property and mechanical strength. <P>SOLUTION: The fuel container equipped with the multilayered molded parts made of a barrier resin (A) layer of at least one kind selected from a group composed of polyvinyl alcohol resin, polyamide and aliphatic polyketone and a thermoplastic resin (B) layer having a soluble parameter (computed from a Fedors expression) of not greater than 11 is provided. The leakage of fuel from a part of the molded parts is extensively improved in the fuel container with such multilayered molded parts. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a fuel container in which a molded part for a fuel container having excellent gasoline barrier properties, heat fusion properties, and mechanical strength is mounted on a fuel container body.

  In recent years, in fuel containers represented by automobiles, the practical application of fuel containers made of metal to thermoplastic resin has been actively promoted in terms of weight reduction, rust prevention, easy molding processability, and recyclability. Have been.

  However, when a fuel container made of a thermoplastic resin is used, permeation and volatilization of a gasoline component from the fuel container body poses a problem. Therefore, a multilayer fuel container containing an ethylene-vinyl alcohol copolymer (hereinafter abbreviated as EVOH) having high gas barrier properties has been developed (Patent Document 1). By including EVOH in the fuel container, permeation and volatilization of gasoline components from the fuel container main body are greatly improved.

  On the other hand, molded parts attached to the fuel container (for example, fuel tubes, gas supply vent lines, pressure relief valves, and connectors to these container bodies) are generally made of high-density polyethylene. Have been. Therefore, the fuel permeates and volatilizes. Therefore, even if the fuel container body has excellent gas barrier properties, the fuel permeates and volatilizes from the molded parts to be connected, and the amount thereof is not negligible.

Therefore, it is conceivable to use a barrier resin (for example, EVOH or the like) instead of high-density polyethylene. However, when the barrier resin alone is used as a molded part for a fuel container, the problem of gasoline permeation and volatilization can be solved, but the heat fusion property with the fuel container body, mechanical strength, impact resistance, etc. It will be unsatisfactory.
JP-A-9-29904 U.S. Pat. No. 2,495,286 JP-A-53-128690 JP-A-59-197427 JP-A-61-91226 JP-A-62-232434 JP-A-62-53332 JP-A-63-3025 JP-A-63-105031 JP-A-63-154737 JP-A-1-149829 JP-A-1-201333 JP-A-2-67319 JP-A-50-44281 DE3021273 JP-A-1-308439

  Therefore, there is a demand for a molded part for a fuel container that exhibits excellent performance in gasoline barrier properties, heat fusion properties, and mechanical strength. In a fuel container equipped with such a molded part, leakage of fuel from a connector portion that connects a fuel tube, a gas vent line of a filler port, a depressurizing valve, and the like to a fuel container body is greatly improved.

  The present invention provides a barrier resin (A) layer having a solubility parameter (calculated from the Fedors equation) exceeding 11 and a thermoplastic resin (B) layer having a solubility parameter (calculated from the Fedors equation) of 11 or less. A fuel container mounted on a fuel container body.

  In a preferred embodiment, the barrier resin (A) layer is at least one selected from the group consisting of a polyvinyl alcohol-based resin, a polyamide and an aliphatic polyketone, and the thermoplastic resin (B) ) Layers.

  In a more preferred embodiment, the barrier resin (A) comprises an ethylene-vinyl alcohol copolymer (A1) having an ethylene content of 5 to 60 mol% and a saponification degree of 85% or more.

  In another preferred embodiment, the barrier resin (A) layer is composed of 10 to 80% by weight of an ethylene-vinyl alcohol copolymer, 1 to 90% by weight of a compatibilizer (C), and (A), ( A resin composition comprising 0 to 89% by weight of a thermoplastic resin (D) having a solubility parameter of 11 or less (calculated from the Fedors equation) other than C).

  In a preferred embodiment, the compatibilizer (C) is a saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, a carboxylic acid-modified polyolefin, and a boronic acid-modified polyolefin. Selected from the group consisting of:

  In a preferred embodiment, the thermoplastic resin (B) layer is a polyolefin resin.

In a further preferred embodiment, the thermoplastic resin (B) layer is made of polyethylene having a density of 0.93 g / cm ³ or more.

  In a more preferred embodiment, the thermoplastic resin (B) layer is a saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, a carboxylic acid-modified polyolefin, and a boronic acid-modified. It is selected from the group consisting of polyolefins.

  In a preferred embodiment, the thermoplastic resin (B) layer is a saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, a carboxylic acid-modified polyolefin, and a boronic acid-modified polyolefin. A thermoplastic resin (D) having at least one compatibilizer (C) selected from the group consisting of 1 to 99% by weight and a solubility parameter other than (C) of 11 or less (calculated from the Fedors equation) It is a resin composition comprising 1 to 99% by weight.

  In another preferred embodiment, at least one of the barrier resin (A) layer and the thermoplastic resin (B) layer contains 1 to 50% by weight of an inorganic filler.

  In a preferred embodiment, the molded part is molded by a multilayer injection molding machine.

  In a preferred embodiment, in the fuel container of the present invention, the molded part is mounted on a fuel container main body via a thermoplastic resin (B) layer.

  In a more preferred embodiment, the molded part is a fuel container connector, a fuel container cap or a fuel container valve.

  In a preferred embodiment, in the fuel container of the present invention, the molded part is attached to the fuel container body by heat fusion.

  The present invention also relates to a fuel container in which a component made of a thermosetting resin (E) is mounted via a molded component on the fuel container on which the molded component is mounted.

  In a preferred embodiment, the thermosetting resin (E) is polymethylene oxide.

  A barrier resin (A) layer having a solubility parameter (calculated from the Fedors equation) exceeding 11 and a thermoplastic resin (B) layer having a solubility parameter (calculated from the Fedors equation) of 11 or less are laminated. The molded part having excellent gasoline barrier properties and exhibits excellent properties in gas barrier properties, impact resistance, heat fusion properties, mechanical strength, stress crack resistance, and organic solvent resistance. In the fuel container equipped with such a molded part, the leakage of fuel from the molded part is greatly improved.

  The present invention provides a barrier resin (A) layer having a solubility parameter (calculated from the Fedors equation) exceeding 11 and a thermoplastic resin (B) layer having a solubility parameter (calculated from the Fedors equation) of 11 or less. The present invention relates to a fuel container in which molded parts formed by lamination are mounted on a fuel container body.

  The "fuel" in the fuel container of the present invention includes not only gasoline but also so-called oxygen-containing gasoline such as gasoline containing alcohol (containing alcohol such as methanol) and gasoline containing MTBE (methyl tertiary butyl ether).

(Barrier resin (A))
The barrier resin (A) used in the present invention has a solubility parameter (calculated from the Fedors equation) of more than 11, and has a barrier property to the fuel filled in the fuel container of the present invention. It is. The barrier resin (A) preferably has a gasoline permeation amount of 100 g · 20 μm / m ² · day (value measured at 40 ° C.-65% RH) or less. The upper limit of the gasoline permeation amount is more preferably 10 g · 20 μm / m ² · day or less, further preferably 1 g · 20 μm / m ² · day or less, and particularly preferably 0.5 g · 20 μm / m ^2. Day or less, and optimally 0.1 g · 20 μm / m ² · day or less. Here, the gasoline used for measuring the gasoline permeation amount is Ref. This is a model gasoline called C, which is mixed at a volume fraction of toluene / isooctane = 1/1.

  Examples of the barrier resin (A) used in the present invention include a polyvinyl alcohol-based resin (A1), a polyamide (A2), and an aliphatic polyketone (A3). These resins may be used alone or in combination. Among these resins, from the viewpoint of gasoline barrier properties, as the barrier resin (A) used in the present invention, polyvinyl alcohol-based resin (A1) and polyamide (A2) are preferable, and in particular, polyvinyl alcohol-based resin (A1) ) Is preferred.

  In the present invention, "polyvinyl alcohol-based resin" refers to a resin obtained by saponifying a vinyl ester polymer or a copolymer of a vinyl ester and another monomer using an alkali catalyst or the like.

  The degree of saponification of the vinyl ester component of the polyvinyl alcohol resin (A1) used in the present invention is preferably 90% or more, more preferably 95% or more, and even more preferably 99% or more. . If the saponification degree is less than 90 mol%, the gas barrier property under high humidity may be reduced, and the gasoline barrier property may be insufficient. The polyvinyl alcohol-based resin (A1) may be a blend of two or more polyvinyl alcohol-based resins having different degrees of saponification. In such a case, the average value calculated from the blending weight ratio is defined as the degree of saponification. The saponification degree of the polyvinyl alcohol-based resin (A1) can be determined by a nuclear magnetic resonance (NMR) method.

  As the polyvinyl alcohol-based resin (A1) used in the present invention, ethylene-vinyl alcohol copolymer is preferable from the viewpoints that it can be melt-molded, has good gas barrier properties under high humidity, and has excellent gasoline barrier properties. Combination (EVOH) is preferred.

  EVOH is preferably obtained by saponifying an ethylene-vinyl ester copolymer. Among them, an ethylene-vinyl alcohol copolymer having an ethylene content of 5 to 60 mol% and a saponification degree of 85% or more is preferable. The lower limit of the ethylene content of EVOH is preferably at least 15 mol%, more preferably at least 20 mol%, further preferably at least 25 mol%. The upper limit of the ethylene content is preferably 55 mol% or less, more preferably 50 mol% or less. If the ethylene content is less than 5 mol%, the melt moldability may deteriorate, and the water resistance and hot water resistance may decrease. On the other hand, if it exceeds 60 mol%, the barrier properties may be insufficient. The saponification degree of the vinyl ester component is preferably 85% or more, more preferably 90% or more, and further preferably 99% or more. If the degree of saponification is less than 85%, the gasoline barrier properties and thermal stability may be insufficient.

  A typical example of the vinyl ester used for the production of EVOH is vinyl acetate, but other fatty acid vinyl esters (such as vinyl propionate and vinyl pivalate) can also be used. EVOH can contain 0.0002 to 0.2 mol% of a vinylsilane compound as a copolymerization component. Here, examples of the vinylsilane-based compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxy-ethoxy) silane, and γ-methacryloxypropylmethoxysilane. Among them, vinyltrimethoxysilane and vinyltriethoxysilane are preferably used. Furthermore, other comonomer such as propylene, butylene, or unsaturated (meth) acrylic acid, methyl (meth) acrylate or ethyl (meth) acrylate, as long as the object of the present invention is not hindered. Carboxylic acid or its ester and vinylpyrrolidone such as N-vinylpyrrolidone can also be copolymerized.

  Furthermore, a boron compound can be blended with EVOH as long as the object of the present invention is not impaired. Here, examples of the boron compound include boric acids, borate esters, borates, and borohydrides. Specifically, examples of boric acids include orthoboric acid, metaboric acid, tetraboric acid, and the like.Examples of borate esters include triethyl borate, trimethyl borate, and the like. Examples include alkali metal salts, alkaline earth metal salts of acids, borax, and the like. Of these compounds, orthoboric acid (hereinafter sometimes simply referred to as boric acid) is preferred.

  When a boron compound is blended, the content of the boron compound is preferably 20 to 2000 ppm, more preferably 50 to 1000 ppm in terms of boron element. By being in this range, it is possible to obtain EVOH in which torque fluctuation during heating and melting is suppressed. If it is less than 20 ppm, such an effect is small, and if it exceeds 2,000 ppm, gelation is likely to occur, resulting in poor moldability.

  It is also preferable that the EVOH used in the present invention contains an alkali metal salt in an amount of 5 to 5000 ppm in terms of an alkali metal element, because it is effective for improving compatibility.

  The more preferable content of the alkali metal salt is 20 to 1000 ppm, more preferably 30 to 500 ppm in terms of an alkali metal element. Here, examples of the alkali metal include lithium, sodium, and potassium, and examples of the alkali metal salt include a monovalent metal aliphatic carboxylate, an aromatic carboxylate, and a metal complex. For example, sodium acetate, potassium acetate, sodium stearate, potassium stearate, sodium salt of ethylenediaminetetraacetic acid and the like can be mentioned. Among them, sodium acetate and potassium acetate are preferred.

  It is also preferable that the EVOH used in the present invention contains a phosphorus compound in an amount of 2 to 200 ppm, more preferably 3 to 150 ppm, and most preferably 5 to 100 ppm in terms of phosphorus element. If the phosphorus concentration in the EVOH is less than 2 ppm or more than 200 ppm, problems may occur in melt moldability and heat stability. In particular, problems such as the occurrence of gel-like bumps and coloring during long-time melt molding are likely to occur.

  The kind of the phosphorus compound to be blended in the EVOH is not particularly limited. Various acids such as phosphoric acid and phosphorous acid and salts thereof can be used. The phosphate may be contained in any form of a first phosphate, a second phosphate, and a third phosphate, and the cationic species thereof is not particularly limited. And alkaline earth metal salts. Among them, it is preferable to add a phosphorus compound in the form of sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, and dipotassium hydrogen phosphate, and particularly preferably sodium dihydrogen phosphate and dipotassium hydrogen phosphate It is.

  In addition, a heat stabilizer, an ultraviolet absorber, an antioxidant, a colorant, another resin (polyamide, polyolefin, etc.), and a plasticizer such as glycerin or glycerin monostearate are blended with EVOH within a range not to impair the object of the present invention. You can also. Further, addition of a metal salt of a higher aliphatic carboxylic acid or a hydrotalcite compound is effective from the viewpoint of preventing EVOH from being deteriorated by heat.

  The preferred melt flow rate (MFR) (190 ° C.-load 2160 g) of the EVOH used in the present invention is 0.1 to 50 g / 10 min, more preferably 0.3 to 40 g / 10 min, and still more preferably. Is 0.5 to 30 g / 10 minutes. However, those having a melting point of around 190 ° C. or exceeding 190 ° C. are measured under a load of 2160 g at a plurality of temperatures equal to or higher than the melting point. Expressed as a value extrapolated to 190 ° C. These EVOH resins can be used alone or in combination of two or more.

  The polyamide (A2) used as the barrier resin (A) of the present invention is a polymer having an amide bond, for example, polycaproamide (nylon-6), polyundecaneamide (nylon-11), polylauryl. Homopolymers such as lactam (nylon-12), polyhexamethylene adipamide (nylon-6,6), polyhexamethylene sebacamide (nylon-6,12), and caprolactam / lauryl lactam copolymer (nylon- 6/12), caprolactam / aminoundecanoic acid polymer (nylon-6 / 11), caprolactam / ω-aminononanoic acid polymer (nylon-6,9), caprolactam / hexamethylene diammonium adipate copolymer (nylon-6) / 6,6), caprolactam / hexamethylenediammonium adipate / Hexamethylenediammonium sebacate copolymer (nylon-6 / 6,6 / 6,12), a polymer of adipic acid and metaxylylenediamine, or a copolymer of hexamethylenediamine and m, p-phthalic acid Aromatic nylon which is a polymer is exemplified. These polyamides can be used alone or in combination of two or more. Among these polyamides, nylon-6 is preferred from the viewpoint of gasoline barrier properties.

  The aliphatic polyketone (A3) used as the barrier resin (A) of the present invention is a carbon monoxide-ethylene copolymer. Examples of the carbon monoxide-ethylene copolymer include carbon monoxide and ethylene. Or those obtained by copolymerizing an unsaturated compound other than ethylene with carbon monoxide and ethylene as the main components. Here, examples of the unsaturated compound other than ethylene include an α-olefin having 3 or more carbon atoms, styrene, a diene, a vinyl ester, and an aliphatic unsaturated carboxylic acid ester. Examples of the copolymer include a random copolymer and an alternating copolymer, and an alternating copolymer having high crystallinity is preferable in terms of barrier properties.

  Among the alternating copolymers, it is preferable from the viewpoint of melt stability that copolymerization with a third component other than carbon monoxide or ethylene is performed because the melting point is lowered. Among the monomers to be copolymerized, preferred are α-olefins, such as propylene, butene-1, isobutene, pentene-1, 4-methylpentene-1, hexene-1, octene-1, and dodecene-1. Among them, α-olefins having 3 to 8 carbon atoms are preferable, and propylene is particularly preferable. The copolymerization amount of these α-olefins is preferably 0.5 to 7% by weight based on the polyketone, from the viewpoint of securing appropriate crystallinity and melt stability.

  The diene to be copolymerized is preferably one having 4 to 12 carbon atoms, and examples thereof include butadiene, isoprene, 1,5-hexadiene, 1,7-octadiene, and 1,9-decadiene. Examples of the vinyl ester include vinyl acetate, vinyl propionate, vinyl pivalate, and the like. Aliphatic unsaturated carboxylic acids, salts and esters thereof include acrylic acid, methacrylic acid, maleic anhydride, maleic acid, itaconic acid, acrylic ester, methacrylic ester, maleic monoester, maleic diester, and fumaric acid. Monoesters, fumaric acid diesters, itaconic acid monoesters, itaconic acid diesters (eg, methyl esters, alkyl esters such as ethyl esters, etc.), acrylates, maleates, and itaconates (as these salts Monovalent or divalent metal salts). These copolymer monomers are not limited to one kind, and may be used in combination of two or more kinds.

  Examples of the method for producing the aliphatic polyketone (A3) include known methods, for example, the methods described in Patent Literature 2, Patent Literature 3, Patent Literatures 4 to 13, and the like. Absent.

  The preferred melt flow rate (MFR) of the aliphatic polyketone used in the present invention is 0.01 to 50 g / 10 min (230 ° C.-load 2160 g), and most preferably 0.1 to 10 g / 10 min. When the MFR is within the above range, the fluidity of the resin is excellent, and the moldability is also excellent.

(Thermoplastic resin (B))
Examples of the thermoplastic resin (B) having a solubility parameter of 11 or less (calculated from the Fedors equation) used in the present invention include a polyolefin resin, a styrene resin, and a polyvinyl chloride resin. When a molded part for a fuel container is mounted on a fuel container made of a thermoplastic resin, it is often mounted by thermal fusion from the viewpoint of simplification of work steps and the like. Generally, a polyolefin resin, preferably high-density polyethylene, is used for the outermost layer of the fuel container body made of a thermoplastic resin in order to obtain sufficient mechanical strength. Since the solubility parameter of the polyolefin-based resin is 11 or less, when the solubility parameter of the thermoplastic resin (B) exceeds 11, the heat-fusibility between the fuel container body and the molded part for the fuel container becomes insufficient. However, the performance of the fuel container of the present invention cannot be sufficiently exhibited. These thermoplastic resins (B) can be used alone or in combination of two or more.

  Among these thermoplastic resins (B), it is preferable to use a polyolefin-based resin from the viewpoint of heat fusion with the fuel container body.

  Examples of the polyolefin resin include high-density, low-density or ultra-low-density polyethylene, carboxylic acid-modified polyolefin, boronic acid-modified polyolefin, polypropylene, α-olefin homopolymer such as polybutene-1, ethylene, propylene, butene-1, Copolymers of α-olefins selected from hexene-1 and the like are exemplified. Further, those obtained by copolymerizing α-olefins with the following components: diolefins, vinyl compounds such as vinyl chloride and vinyl acetate, and unsaturated carboxylic esters such as acrylic acid esters and methacrylic acid esters are also included. Examples of the styrene resin include polystyrene, acrylonitrile-butadiene-styrene copolymer resin (ABS), acrylonitrile-styrene copolymer resin (AS), block copolymer with styrene-isobutylene, and copolymer with styrene-butadiene. Alternatively, a block copolymer with styrene-isoprene and the like can be mentioned.

Among the above polyolefin resins, polyethylene having a density of 0.93 g / cm ³ or more, saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, carboxylic acid-modified polyolefin, and Boronic acid-modified polyolefins are preferred.

  The ethylene-vinyl acetate copolymer saponified product having an ethylene content of 70 to 99 mol% and a degree of saponification of a vinyl acetate component of 40% or more used in the present invention has a high ethylene content from the viewpoint of improving compatibility. Is more preferably 72 to 96 mol%, and even more preferably 72 to 94 mol%. The saponification degree of the vinyl acetate component is preferably 45% or more. There is no particular upper limit for the degree of saponification, and those having a saponification degree of substantially 100% can also be used.

  The saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a saponification degree of a vinyl acetate component of 40% or more is preferably a barrier resin (A), particularly preferably EVOH. Used in combination. If the degree of saponification of the vinyl acetate component is less than 40%, or if the ethylene content is more than 99% by mole, the compatibility with EVOH may be reduced and the moldability may be deteriorated. On the other hand, when the ethylene content is less than 70 mol%, the heat-fusibility between the molded part for a fuel container and the fuel container body becomes insufficient.

  Melt flow rate (MFR) of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a saponification degree of a vinyl acetate component of 40% or more (210 ° C., load 2160 g) used in the present invention. Is preferably 0.1 g / 10 min or more, preferably 0.5 g / 10 min or more, 100 g / 10 min or less, more preferably 50 g / 10 min or less, and most preferably 30 g / 10 min. It is desirable that:

  The carboxylic acid-modified polyolefin used in the present invention refers to an olefin, in particular, a copolymer of an α-olefin and an unsaturated carboxylic acid or an anhydride thereof, and a polyolefin having a carboxyl group in a molecule and a polyolefin. Also included are those in which all or a part of the carboxyl group contained is present in the form of a metal salt. Examples of the polyolefin serving as the base of the carboxylic acid-modified polyolefin include polyethylene (eg, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), very low density polyethylene (VLDPE)), polypropylene, copolymerized polypropylene, ethylene -Various polyolefins such as a vinyl acetate copolymer and an ethylene- (meth) acrylate copolymer.

  Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, monomethyl maleate, monoethyl maleate, and itaconic acid, and acrylic acid or methacrylic acid is particularly preferable. The content of the unsaturated carboxylic acid is preferably 0.5 to 20 mol%, more preferably 2 to 15 mol%, and still more preferably 3 to 12 mol%. Examples of the unsaturated carboxylic anhydride include itaconic anhydride and maleic anhydride, and maleic anhydride is particularly preferred. The content of the unsaturated carboxylic anhydride is preferably 0.0001 to 5 mol%, more preferably 0.0005 to 3 mol%, and still more preferably 0.001 to 1 mol%. Other monomers that may be contained in the copolymer include vinyl acetate, vinyl esters such as vinyl propionate, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, and n-acrylate. -Butyl, 2-ethylhexyl acrylate, methyl methacrylate, isobutyl methacrylate, unsaturated maleic acid esters such as diethyl maleate, carbon monoxide and the like.

  Examples of the metal ion in the metal salt of the carboxylic acid-modified polyolefin include alkali metals such as lithium, sodium, and potassium; alkaline earth metals such as magnesium and calcium; and transition metals such as zinc. It is preferable in terms of solubility. The degree of neutralization of the carboxylic acid-modified polyolefin in the metal salt is preferably 100% or less, particularly 90% or less, and more preferably 70% or less. The lower limit of the degree of neutralization is usually 5% or more, preferably 10% or more, and more preferably 30% or more.

  The melt flow rate (MFR) (190 ° C.-load 2160 g) of the carboxylic acid-modified polyolefin used in the present invention is preferably 0.01 to 50 g / 10 min, more preferably 0.05 to 30 g / 10 min, and still more preferably. Is 0.1 to 10 g / 10 minutes. These carboxylic acid-modified polyolefins can be used alone or in combination of two or more.

  The boronic acid-modified polyolefin used in the present invention is a polyolefin having at least one functional group selected from 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. It is.

  The boronic acid group used in the present invention, a polyolefin having at least one functional group selected from a boronic acid group and a boron-containing group that can be converted to a boronic acid group in the presence of water, a boronic acid group, At least one functional group selected from the group consisting of a boronic acid group or a boron-containing group that can be converted to a boronic acid group or a borinic acid group in the presence of water is bonded to the main chain, a side chain, or a terminal by a boron-carbon bond. It is a polyolefin. Of these, a polyolefin having the above functional group bonded to a side chain or a terminal is preferable, and a polyolefin having a terminal bonded is most suitable. Here, the term "end" means one end or both ends. Further, the carbon of the boron-carbon bond is derived from a polyolefin base polymer described later or from a boron compound reacted with the base polymer. Preferable examples of the boron-carbon bond include a bond between boron and an alkylene group in a main chain or a terminal or side chain. In the present invention, a polyolefin having a boronic acid group is suitable, and therefore, this point will be described below. In the present invention, the boronic acid group is represented by the following formula (I).

  Further, as the boron-containing group which can be converted into a boronic acid group in the presence of water (hereinafter simply referred to as boron-containing group), the boronic acid group represented by the above formula (I) upon hydrolysis in the presence of water Any boron-containing group may be used as long as it is a boron-containing group that can be converted to a boron-ester group represented by the following general formula (II), a boronic anhydride group represented by the following general formula (III), Examples include boronate groups represented by the following general formula (IV).

(Wherein X and Y are a hydrogen atom, an aliphatic hydrocarbon group (such as a linear or branched alkyl group or alkenyl group having 1 to 20 carbon atoms), an alicyclic hydrocarbon group (a cycloalkyl group, X and Y may be the same or different, and X and Y may be bonded to each other, such as a cycloalkenyl group or an aromatic hydrocarbon group (a phenyl group or a biphenyl group). However, this is excluded when both X and Y are hydrogen atoms, and R ¹ , R ² and R ³ are the same as those for X and Y described above for a hydrogen atom, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon. R ¹ , R ² , R ³ may be the same or different, and M represents an alkali metal or an alkaline earth metal, and X, Y, R ¹ , R ² and R ³ are other groups such as a carboxyl group and a halogen atom. May be included.)

  Specific examples of the boronic esters represented by the general formulas (II) to (IV) include boronic acid dimethyl ester group, boronic acid diethyl ester group, boronic acid dipropyl ester group, boronic acid diisopropyl ester group, and boronic acid dibutyl ester Group, dihexyl boronate group, dicyclohexyl boronate group, ethylene glycol ester boronate group, propylene glycol ester boronate group (1,2-propanediol ester boronate group, 1,3-propanediol ester boronate group), Boronic acid ester groups such as boronic acid trimethylene glycol ester group, boronic acid neopentyl glycol ester group, boronic acid catechol ester group, boronic acid glycerin ester group, and boronic acid trimethylolethane ester group; boronic acid anhydride group; Alkali metal base Ron acid, alkaline earth metal base such as boronic acid. Among these functional groups, a boronic acid ester group such as a boronic acid ethylene glycol ester group is particularly preferred from the viewpoint of compatibility with EVOH. The above-mentioned boron-containing group that can be converted into a boronic acid group or a borinic acid group in the presence of water is a reaction between a polyolefin and water or a liquid mixture of water and an organic solvent (toluene, xylene, acetone, etc.). It means a group that can be converted into a boronic acid group or a borinic acid group when hydrolyzed at a reaction temperature of 25 ° C. to 150 ° C. for a time of 10 minutes to 2 hours.

  The content of the functional group is not particularly limited, but is preferably 0.0001 to 1 meq / g (milliequivalent / g), and particularly preferably 0.001 to 0.1 meq / g. It is surprising that the presence of such a small amount of functional groups significantly improves the compatibility and the like of the resin composition.

  Examples of the base polymer of the polyolefin having a boron-containing group include olefin monomers represented by α-olefins such as ethylene, propylene, 1-butene, isobutene, 3-methylpentene, 1-hexene, and 1-octene. No.

  The base polymer is used as a polymer composed of one, two or three or more of these monomers. Among these base polymers, in particular, ethylene polymers ｛ultra low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylate Suitable examples thereof include a copolymer, a metal salt of an ethylene-acrylic acid copolymer (Na, K, Zn-based ionomer), and an ethylene-propylene copolymer｝.

  Next, a typical method for producing an olefin polymer having a boronic acid group and a boron-containing group used in the present invention will be described. Olefin polymers having a boronic acid group or a boron-containing group that can be converted to a boronic acid group in the presence of water can be obtained by adding a borane complex and a trialkyl borate to an olefin polymer having a carbon-carbon double bond under a nitrogen atmosphere. An olefin polymer having a boronic acid dialkyl ester group is obtained by reacting an ester, and is then obtained by reacting with water or an alcohol. When an olefin polymer having a double bond at a terminal is used as a raw material in this process, an olefin polymer having a boronic acid group at the terminal or a boron-containing group that can be converted to a boronic acid group by the presence of water can be obtained. When an olefin polymer having a double bond in the side chain or main chain is used as a raw material, an olefin polymer having a boronic acid group or a boron-containing group which can be converted to a boronic acid group in the presence of water in the side chain Is obtained.

  Typical methods for producing an olefin polymer having a double bond as a raw material include: 1) a method using a trace amount of a double bond at a terminal of a normal olefin polymer; 2) a normal olefin polymer. A method for producing an olefin polymer having a double bond at a terminal by thermal decomposition under oxygen-free conditions; 3) an olefin monomer and a diene monomer by copolymerization of an olefin monomer and a diene polymer. A method for obtaining a copolymer with a body. For 1), a known method for producing an olefin-based polymer can be used. In particular, a method in which hydrogen is not used as a chain transfer agent and a metallocene-based polymerization catalyst is used as a polymerization catalyst (for example, DE 4030399) is preferable. The method 2) can be obtained by thermally decomposing an olefin polymer at a temperature of 300 to 500 ° C. under an oxygen-free condition such as a nitrogen atmosphere or a vacuum condition by a known method (for example, US Pat. No. 2,835,659, US Pat. No. 3,087,922). . For 3), a method for producing an olefin-diene-based polymer using a known Ziegler-based catalyst (for example, Patent Documents 14 and 15) can be used.

  As the borane complex, borane-tetrahydrofuran complex, borane-dimethylsulfide complex, borane-pyridine complex, borane-trimethylamine complex, borane-triethylamine and the like are preferable. Among these, a borane-triethylamine complex and a borane-trimethylamine complex are more preferred. The amount of the borane complex to be charged is preferably in the range of 1/3 equivalent to 10 equivalent relative to the double bond of the olefin polymer. As the trialkyl borate, a lower alkyl borate such as trimethyl borate, triethyl borate, tripropyl borate and tributyl borate is preferable. The amount of the trialkyl borate to be charged is preferably in the range of 1 to 100 equivalents to the double bond of the olefin polymer. It is not necessary to use a solvent, but if used, a saturated hydrocarbon solvent such as hexane, heptane, octane, decane, dodecane, cyclohexane, ethylcyclohexane, and decalin is preferable.

  The reaction to be introduced is carried out at a reaction temperature of 25 ° C to 300 ° C, preferably 100 to 250 ° C, and a reaction time of 1 minute to 10 hours, preferably 5 minutes to 5 hours.

  As a condition for reacting water or alcohols, an organic solvent such as toluene, xylene, acetone or ethyl acetate is usually used as a reaction solvent, and water or alcohols such as methanol, ethanol, butanol; ethylene glycol, 1,2-propane A polyhydric alcohol such as diol, 1.3-propanediol, neopentelglycol, glycerin, trimethylolethane, pentaerythritol, or dipentaerythritol is used in a large excess of 1 to 100 equivalents or more with respect to the boronic acid group. , At a temperature of 25 ° C to 150 ° C for about 1 minute to 1 day. In addition, the boron-containing group which can be converted into a boronic acid group among the above functional groups refers to a reaction time of 10 minutes to 2 hours in water or a mixed solvent of water and an organic solvent (toluene, xylene, acetone, etc.). A group which can be converted to a boronic acid group when hydrolyzed under the conditions of a reaction temperature of 25 ° C to 150 ° C.

  The suitable melt flow rate (MFR) (190 ° C.-load 2160 g) of the thermoplastic resin (B) used in the present invention is preferably 0.01 to 100 g / 10 min, more preferably 0.03 to 50 g / 10. Min, optimally between 0.1 and 30 g / 10 min. However, those having a melting point of around 190 ° C. or exceeding 190 ° C. are measured under a load of 2160 g at a plurality of temperatures equal to or higher than the melting point. Expressed as a value extrapolated to 190 ° C.

(Compatibilizer (C))
The fuel container of the present invention is obtained by mounting a molded component formed by laminating a barrier resin (A) layer and a thermoplastic resin (B) layer on a fuel container body. In this case, the compatibilizing agent (C) is contained in the barrier resin (A) layer, or the solubility parameter of 11 or less other than the compatibilizing agents (C) and (C) as the thermoplastic resin (B) layer. By using a resin composition comprising a thermoplastic resin (D) having (calculated from the Fedors equation), the adhesion between the layers of the obtained multilayer molded part (for a fuel container) can be improved.

  The compatibilizer (C) is not particularly limited, but preferred examples thereof include a saponified ethylene-vinyl acetate copolymer (C1) having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, carboxylic acid Modified polyolefin (C2), boronic acid-modified polyolefin (C3) and the like. These compatibilizers (C) may be used alone or in combination of two or more.

(Thermoplastic resin (D))
Examples of the thermoplastic resin (D) include a polyolefin resin, a styrene resin, and a polyvinyl chloride resin. Among these, a polyolefin-based resin is particularly preferable from the viewpoint of the heat-fusing property and economical efficiency of the molded part. When the solubility parameter of the thermoplastic resin (D) exceeds 11, the heat-fusibility of the molded part for a fuel container of the present invention with the fuel container body becomes insufficient.

  Examples of the polyolefin resin include homopolymers of α-olefins such as high-density or low-density polyethylene, polypropylene, and polybutene-1, and copolymers of α-olefins selected from ethylene, propylene, butene-1, hexene-1, and the like. Polymers are exemplified.

Among them, when polyethylene having a density of 0.93 g / cm ³ or more is used as the thermoplastic resin (D), it is preferable from the viewpoint that the effect of improving impact resistance and heat fusion property is excellent. Since the outermost layer of the fuel container body made of a thermoplastic resin is often made of high-density polyethylene, adopting such a configuration greatly enhances the effect of improving the heat-fusibility. Polyethylene preferably has a density of 0.93 g / cm ³ or more, and if the density is less than 0.93 g / cm ³ , the effect of improving mechanical strength such as impact resistance may be insufficient.

(Resin additive)
The resin composition used in the present invention may contain appropriate additives (for example, a heat stabilizer, a plasticizer, an antioxidant, an ultraviolet absorber, a coloring agent, etc.). Is used in a range that does not inhibit the effects of the present invention. Further, addition of a metal salt of a higher aliphatic carboxylic acid or a hydrotalcite compound is effective from the viewpoint of preventing EVOH from being deteriorated by heat when the barrier resin (A) is EVOH.

Here, as the hydrotalcite compound, in _{particular, M x Al y (OH)} 2x + 3y-2z (A) z · aH 2 O (M is Mg, Ca or Zn, A is CO ₃ or _HPO 4, x, y , Z, and a are positive numbers). Particularly preferred examples include the following hydrotalcite compounds.

_{Mg 6 Al 2 (OH) 16} CO 3 · 4H 2 O
_{Mg 8 Al 2 (OH) 20} CO 3 · 5H 2 O
_{Mg 5 Al 2 (OH) 14} CO 3 · 4H 2 O
_{Mg 10 Al 2 (OH) 22} (CO 3) 2 · 4H 2 O
_{Mg 6 Al 2 (OH) 16} HPO 4 · 4H 2 O
_{Ca 6 Al 2 (OH) 16} CO 3 · 4H 2 O
_{Zn 6 Al 6 (OH) 16} CO 3 · 4H 2 O
_{Mg 4.5 Al 2 (OH) 13} CO 3 · 3.5H 2 O
As a hydrotalcite compound, [Mg _0.75 Zn _0.25 ] _0.67 Al _0.33 (OH) ₂ (CO ₂ ) which is a hydrotalcite-based solid solution described in Patent Document 16 (US Pat. No. 4,954,557) ₃ ) A material such as _0.167 / 0.45H ₂ O can also be used.

  The metal salt of a higher aliphatic carboxylic acid refers to a metal salt of a higher fatty acid having 8 to 22 carbon atoms. Examples of the higher fatty acid having 8 to 22 carbon atoms include lauric acid, stearic acid, myristic acid and the like. Examples of the metal include sodium, potassium, magnesium, calcium, zinc, barium, aluminum and the like. Of these, alkaline earth metals such as magnesium, calcium and barium are preferred.

  The content of the metal salt of these higher aliphatic carboxylic acids or the hydrotalcite compound is preferably 0.01 to 3 parts by weight, more preferably 0.05 to 2.0 parts by weight, based on the total weight of the resin composition. 5 parts by weight.

(Multilayer molded parts)
In the fuel container of the present invention, a molded component formed by laminating the barrier resin (A) layer and the thermoplastic resin (B) layer is mounted on the fuel container body. Hereinafter, the multilayer molded part will be described first, and then the fuel container will be described.

  The multilayer molded component used in the present invention includes a barrier resin (A) layer and a thermoplastic resin (B) layer. By forming a multilayer structure of the barrier resin (A) layer and the thermoplastic resin (B) layer, the thermoplastic resin (B) layer has heat-fusing properties, mechanical strength such as impact resistance, and barrier properties. It is possible to obtain a multilayer molded part having both gasoline barrier properties and organic solvent resistance of the resin (A) layer.

  Further, as described above, when the molded component is formed by laminating the barrier resin (A) and the thermoplastic resin (B), it is necessary to include the compatibilizer (C) in the barrier resin (A) layer. And a resin composition composed of a thermoplastic resin (D) having a solubility parameter of 11 or less (calculated from the Fedors equation) other than the compatibilizers (C) and (C) as the thermoplastic resin (B) layer. Thereby, the adhesiveness between the respective layers can be improved.

(Barrier resin (A) layer)
As the barrier resin (A) layer, a polyvinyl alcohol-based resin (A1) layer, a polyamide resin (A2) layer, and an aliphatic polyketone (A3) layer are used. A polyvinyl alcohol-based resin (A1) layer is preferable, and among them, a layer of EVOH having an ethylene content of 5 to 60 mol% and a saponification degree of 85% or more is preferable.

  The barrier resin (A) layer is composed of a barrier resin (A), a compatibilizer (C) and a thermoplastic resin (D) in order to improve delamination with the thermoplastic resin (B) layer. A barrier resin composition may be used.

  Examples of the compatibilizer (C) used in the barrier resin composition include saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, a carboxylic acid-modified polyolefin, and a boronic acid. At least one resin selected from the group consisting of modified polyolefins is preferred.

  Although the thermoplastic resin (D) is not an essential component, the addition of the thermoplastic resin (D) further enhances the mechanical strength of the barrier resin (A) layer and the interlayer adhesion with the thermoplastic resin (B) layer. It is preferable in that it can be improved, and by selecting an appropriate resin, it is also possible to enjoy cost advantages.

  The barrier resin composition may comprise 10 to 80% by weight of the barrier resin (A), 1 to 90% by weight of the compatibilizer (C), and 0 to 89% by weight of the thermoplastic resin (D). It is preferable from the viewpoint of improving barrier properties and interlayer adhesion.

  The content of the barrier resin (A) (especially preferably, EVOH) is 10 to 80% by weight, and the lower limit of the content is preferably 20% by weight or more, and more preferably 30% by weight or more. It is. Further, the upper limit of the content of the barrier resin (A) is preferably 70% by weight or less, more preferably 60% by weight or less. If the content of the barrier resin (A) is less than 10% by weight, sufficient gasoline barrier properties cannot be obtained. If the content exceeds 80% by weight, the effect of improving the interlayer adhesion to the thermoplastic resin (B) layer may be insufficient.

  The content of the compatibilizer (C) is 1 to 90% by weight, and the lower limit is preferably 3% by weight or more, more preferably 5% by weight or more. The upper limit of the content of the compatibilizer (C) is preferably 80% by weight or less, more preferably 70% by weight or less. When the content of the compatibilizer (C) is less than 1% by weight, the effect of improving the interlayer adhesion with the thermoplastic resin (B) layer becomes insufficient, and when it exceeds 90% by weight, a sufficient gasoline barrier is obtained. I can not get the nature.

  The lower limit of the content of the thermoplastic resin (D) is preferably 1% by weight or more, and more preferably 5% by weight or more. The upper limit of the content of the thermoplastic resin (D) is preferably 80% by weight or less, more preferably 70% by weight or less. When the content of the thermoplastic resin (D) exceeds 89% by weight, the gasoline barrier property becomes insufficient.

(Thermoplastic resin (B) layer)
Examples of the thermoplastic resin (B) having a solubility parameter of 11 or less used for the multilayer molded part used in the present invention include a polyolefin resin, a styrene resin, and a polyvinyl chloride resin. Since the outermost layer of the fuel container body is usually a polyolefin-based resin, when the solubility parameter of the thermoplastic resin (B) exceeds 11, the heat-fusibility of the molded part for a fuel container of the present invention with the container body is reduced. Insufficient.

  Examples of the polyolefin resin include homopolymers of α-olefins such as high-density or low-density polyethylene, polypropylene, and polybutene-1, and copolymers of α-olefins selected from ethylene, propylene, butene-1, hexene-1, and the like. Polymers are exemplified. In addition, the following components are combined with the α-olefin: diolefins, vinyl compounds such as vinyl chloride and vinyl acetate, unsaturated carboxylic acids such as maleic acid, and unsaturated carboxylic esters such as acrylates and methacrylates. Polymerized ones are also included. Further, boronic acid-modified polyolefins are also preferred. Examples of the styrene resin include polystyrene, acrylonitrile-butadiene-styrene copolymer resin (ABS), acrylonitrile-styrene copolymer resin (AS), block copolymer with styrene-isobutylene, and copolymer with styrene-butadiene. Alternatively, a block copolymer with styrene-isoprene and the like can be mentioned. Among these, polyolefin-based resins are particularly suitable from the viewpoints of heat-fusing property, mechanical strength, economical efficiency and the like of molded parts. As the thermoplastic resin (B), the resins exemplified above can be used alone or in combination of two or more.

Among these, polyethylene having a density of 0.93 g / cm ³ or more, saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, carboxylic acid-modified polyolefin and boronic acid-modified polyolefin It is preferable to use at least one selected from the group consisting of:

When polyethylene having a density of 0.93 g / cm ³ or more is used as the thermoplastic resin (B), the interlayer adhesion with the EVOH (A) layer is not high. Strength is difficult to obtain. However, since the outermost layer of the fuel container body made of a thermoplastic resin is often made of high-density polyethylene, the adoption of such a configuration particularly enhances the effect of improving the heat-fusibility. The polyethylene preferably has a density of 0.93 g / cm ³ or more, and if the density is less than 0.93 g / cm ³ , the mechanical strength of the multilayer molded part for a fuel container may be insufficient.

When the carboxylic acid-modified polyolefin or the boronic acid-modified polyolefin is used as the thermoplastic resin (B) layer, the multilayer molded part for the fuel container and the fuel are compared with the case where polyethylene having a density of 0.93 g / cm ³ or more is used. Although the heat-fusibility with the container body is reduced to some extent, high interlayer adhesion with the barrier resin (A) layer is obtained, which is preferable from the viewpoint of obtaining a multilayer molded part having excellent mechanical strength.

  As the thermoplastic resin (B) layer, the compatibilizer (C) and the thermoplastic resin (C) are used from the viewpoints of improving the mechanical strength of the obtained molded part for a fuel container and improving the heat-fusibility with the fuel container body. D) is preferably used. By using such a resin composition, compared with the case where the thermoplastic resin (B) layer is composed of the compatibilizer (C) alone, or the case where the thermoplastic resin (D) is composed of the thermoplastic resin (D) alone, Performance can be obtained. In other words, from the viewpoint of the heat fusion property with the fuel container body, the thermoplastic resin (B) layer is generally lower than the case where the compatibilizing agent (C) is used alone, but the case where the compatibilizing agent (C) is used alone It is possible to obtain a molded article superior to the above. On the other hand, from the viewpoint of the interlayer adhesion with the barrier resin (A) layer, the thermoplastic resin (B) layer is generally lower than the case where the compatibilizing agent (C) is used alone, but the thermoplastic resin (D) alone is used. A better molded product can be obtained than in the case of (1). As described above, from the viewpoint of obtaining a molded article excellent in both heat fusion with the fuel container body and interlayer adhesion with the barrier resin (A) layer in a well-balanced manner, the compatibilizer (C ) And the thermoplastic resin (D) are preferably used as the thermoplastic resin (B) layer.

  The compatibilizer (C) is selected from the group consisting of saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, carboxylic acid-modified polyolefin, and boronic acid-modified polyolefin. At least one kind of resin is preferable, and among them, carboxylic acid-modified polyolefin or boronic acid-modified polyolefin is preferable.

As the thermoplastic resin (D), it is particularly preferable to use polyethylene having a density of 0.93 g / cm ³ or more from the viewpoint of the mechanical strength of the multilayer molded part for a fuel container and the heat-fusibility with the fuel container body. If the density is less than 0.93 g / cm ³ , mechanical strength such as impact resistance may be insufficient. When polyethylene having a density of 0.93 g / cm ³ or more is used as the thermoplastic resin (D), the molded part for a fuel container having such a configuration is inferior in impact resistance to the conventional product, but has a lower gasoline barrier property than the conventional product. A great improvement effect is seen.

  A preferred resin composition is a resin composition comprising 1 to 99% by weight of the compatibilizer (C) and 99 to 1% by weight of the thermoplastic resin (D), wherein the compatibilizer (C) is 1% by weight. If it is less than the above, there is a possibility that the effect of improving the interlayer adhesion between the EVOH (A) layer and the thermoplastic resin (D) layer may be insufficient, and the mechanical strength of the resulting multilayer molded part for a fuel container may be reduced. is there. When the content of the thermoplastic resin (D) is less than 1% by weight, the effect of improving the heat sealability of the multilayer molded part for a fuel container may be insufficient.

(Addition of inorganic filler)
An inorganic filler may be added to either or both of the barrier resin (A) layer and the thermoplastic resin (B) layer. When an inorganic filler is added to the barrier resin (A) layer, it is preferable from the viewpoint of improving gasoline barrier properties. Further, when an inorganic filler is added to the thermoplastic resin (B) layer, it is possible to obtain improvement effects such as improvement in mechanical strength and improvement in organic solvent resistance represented by reduction of swelling by gasoline.

  Preferred examples of the inorganic filler used in the present invention include, but are not particularly limited to, mica, sericite, glass flake, and talc. These inorganic fillers can be used alone or as a mixture of a plurality.

  The content of the inorganic filler in the present invention is preferably 1 to 50% by weight, and the lower limit of the content is more preferably 5% by weight or more, further preferably 10% by weight or more, and most preferably 15% by weight. % Or more. Further, the upper limit of the content is more preferably 45% by weight or less, and further preferably 40% by weight or less. If the amount is less than 1% by weight, the effect of improving mechanical strength and gasoline barrier properties may be unsatisfactory. On the other hand, if it exceeds 50% by weight, flow abnormalities are likely to occur during molding, causing sink marks, weld lines and the like, and there is a possibility that a molded article with good appearance cannot be obtained.

(Layer composition of multilayer molded parts)
The layer configuration of the multilayer molded part used in the present invention is not particularly limited, but when the barrier resin (A) layer is A and the thermoplastic resin (B) layer is B, (outside) A / B (inside), (Outside) B / A / B (inside), (outside) B / A / B / A / B (inside) are exemplified as suitable ones. In particular, when the multilayer molded part for a fuel container of the present invention is molded by a two-color molding machine, the A / B configuration is preferable from the viewpoint of ease of molding, and particularly, the stress crack resistance of the molded part. From the viewpoint, the (outside) A / B (inside) configuration is preferable. On the other hand, when molded by co-injection molding, from the viewpoint of easiness of molding, easiness of mold design, cost merit, etc., it should have a (outer) B / A / B (inner) configuration. Is preferred. Here, (inner) indicates the inner layer, that is, the layer on the side that directly contacts the fuel. The thermoplastic resin (B) layer may have a multilayer structure as long as the effect of the present invention is not impaired, and may have a multilayer structure including an adhesive resin layer and a polyolefin-based resin layer, or a thermoplastic resin. It may have a multilayer structure including a resin composition layer (such as a recovery layer) obtained by blending (B) and the barrier resin (A) and a polyolefin-based resin layer.

  Although the thickness of the barrier resin (A) layer is not particularly limited, when the barrier resin (A) layer is substantially composed of only the barrier resin (A), the thickness of each layer, gasoline barrier property and mechanical properties From the viewpoint of strength and the like, the thickness of the barrier resin (A) layer is preferably 0.5 to 50% of the total layer thickness. The thickness of the barrier resin (A) layer is more preferably from 1 to 40%, even more preferably from 3 to 30%, based on the total thickness of the layer.

  When the barrier resin (A) layer is a resin composition, the thickness ratio of the barrier resin (A) layer and the thermoplastic resin (B) layer is the same by changing the content of the component (A). However, the gasoline barrier properties of the multilayer molded parts are different. That is, when the compounding ratio of the component (A) in the barrier resin (A) layer is large, the gasoline barrier property can be maintained even if the thickness of the barrier resin (A) layer is small, but the barrier resin (A) layer has When the mixing ratio of the component (A) is small, it is necessary to increase the thickness of the barrier resin (A) layer in order to maintain gasoline barrier properties. As described above, the preferred thickness of the barrier resin (A) layer varies depending on the composition of the barrier resin (A) layer, but generally, the thickness of the resin composition (A) layer is less than the total thickness of the layer. It is preferably 30 to 90%. More preferably, the thickness of the resin composition (A) layer is 35 to 85% of the total layer thickness, and optimally 40 to 80%.

(Manufacture of multilayer molded parts)
When the compatibilizer (C) and the thermoplastic resin (D) are blended in the barrier resin (A) layer and the thermoplastic resin (B) layer used in the present invention, or the barrier resin (A) layer When the thermoplastic resin (B) layer is a resin composition containing an inorganic filler, the desired resin composition can be easily obtained by melt-kneading the components with a usual melt-kneading apparatus. The method of blending the components is not particularly limited, but may be a simple combination of a barrier resin (A), a thermoplastic resin (B), a compatibilizer (C), and a thermoplastic resin (D). A method of melt-kneading with a screw or twin screw extruder, pelletizing and drying, and the like. In the melt compounding operation, there is a possibility that the blend becomes non-uniform, and gels and lumps are generated and mixed.Therefore, in the case of blend pelletization, use an extruder with a high kneading degree as much as possible. And extruded at a low temperature.

  As a method for obtaining a multilayer molded part used in the present invention, for example, an appropriate molding method in the field of general polyolefin is used, but a multilayer molded part for a fuel container exemplified by a connector, a cap, a valve, and the like generally has a shape. Therefore, molding by a multilayer injection molding method is particularly preferable. Examples of the multilayer injection molding include two-color molding, insert injection molding, and co-injection molding, and are appropriately selected depending on the shape of a desired molded product, and are not particularly limited.

  Here, the two-color molding refers to, for example, using a molding machine having two sets of injection mechanisms, injecting the molten barrier resin (A) or thermoplastic resin (B) into a single mold, and then molding the thermoplastic resin. (B) or the barrier resin (A) is injected. For the two-color molding, a method in which the mold is inverted is conventionally used, but a core-back method or the like can also be appropriately selected and is not particularly limited. As an example of the mold reversal method, for example, when the barrier resin (A) layer is A and the thermoplastic resin (B) layer is B, (1) first, after injecting the thermoplastic resin (B), A method of inverting the mold and subsequently injecting the barrier resin (A) to obtain a two-layer structure of A / B. (2) Injecting the thermoplastic resin (B) and inverting the mold to obtain a barrier property There is a method of injecting the resin (A), inverting the mold again, and injecting the thermoplastic resin (B) to obtain a three-layer structure of B / A / B, but is not particularly limited.

  In the insert injection molding, for example, injection molding is performed after mounting a molded product in advance on a mold. For example, after a molded article made of the barrier resin (A) or a molded article made of the thermoplastic resin (B) is obtained by injection molding, the molded article is mounted on an insert injection molding machine, and the thermoplastic resin (B) and / or Alternatively, a two-layer component of A / B, a three-layer component of B / A / B layer, and the like obtained by injecting the barrier resin (A) may be mentioned, but there is no particular limitation.

  Co-injection molding refers to, for example, using a molding machine having two injection cylinders, performing a single clamping operation on a single mold, and melting the barrier resin (A) and the thermoplastic resin (B) respectively. By alternately injecting into the concentric nozzles from the injection cylinder at a different timing, or simultaneously injecting into the concentric nozzles. For example, (1) the thermoplastic resin (B) layer for the inner and outer layers is first injected, and then the barrier resin (A) serving as the intermediate layer is injected to form a three-layer structure of B / A / B layers. A method for obtaining a molded article, or (2) first injecting the thermoplastic resin (B) layer for the inner and outer layers, then injecting the barrier resin (A), and simultaneously or afterward, injecting the thermoplastic resin (B) There is a method of injecting the layer again to obtain a molded product having a five-layer structure of the B / A / B / A / B layer, but the method is not particularly limited.

(Molded parts and fuel container body with molded parts attached)
The fuel container of the present invention is a container capable of suitably storing not only gasoline but also so-called oxygen-containing gasoline, such as alcohol-containing gasoline and MTBE-containing gasoline, and includes a fuel container main body and a molded part attached to the fuel container main body. Become.

  The fuel container main body is preferably made of a thermoplastic resin, and is usually made of a resin having a multilayer structure having a barrier resin layer in an intermediate layer, and a polyolefin layer is disposed in an outermost layer. It is preferable in terms of strength and the like. EVOH is suitably used as the barrier resin layer, and EVOH having an ethylene content of 5 to 60 mol% and a saponification degree of 90% or more is preferable. The outermost layer polyolefin is preferably high-density polyethylene.

  The molded part used in the present invention refers to a molded part used by being attached to a fuel container body, and specifically includes a fuel container connector, a fuel container cap, a fuel container valve, and the like. Not limited. Preferably, they are a fuel container connector and a fuel container valve.

  The method of mounting the molded part on the fuel container body is not particularly limited, and examples thereof include a screw-in type, a fitting-in type, and a heat-fusion type. It is particularly preferable from the viewpoint of suppressing fuel leakage from the fuel cell. A general method is used for heat fusion. After the fusion surface of the fuel container main body and / or the molded part for the fuel container is heated by a heater or the like, a method of performing fusion, the fuel container main body and the molded part are bonded together. Examples include, but are not limited to, a method of performing high-frequency welding and a method of performing ultrasonic welding on the fuel container body and the molded component.

  Examples of the usage of the molded component as the molded component connector include a configuration in which the molded component is used as a fuel container connector mounted on the fuel container main body, a configuration in which a flexible fuel transport pipe is mounted, and the like. Not limited. Examples of the method of attaching this connector to the fuel container body include a screw-in type, a plug-in type, and joining by heat fusion. It is preferable to be mounted by fusion. For this reason, it is particularly preferable that this connector is excellent in heat fusion with the fuel container body. It is particularly preferable that the connector has excellent gasoline barrier properties in order to suppress fuel leakage from the fuel container main body and the mounting portion of the connector. Further, it is preferable that the connector has excellent stress crack resistance and organic solvent resistance from the viewpoint of long-term continuous use of a molded part for a fuel container, that is, from the viewpoint of product life.

  In a preferred embodiment of the fuel container connector, a more flexible fuel transport pipe is joined to the fuel container connector joined to the fuel container body. Therefore, when the vehicle is running, when fuel is supplied from the fuel container to the engine, or when fuel is received from the fuel supply port to the fuel container, continuous connection to the connector due to vibration of the fuel container itself or vibration of the transport pipe is caused. Load occurs. From these viewpoints, it is desirable that the fuel container connector is excellent in impact resistance, stress crack resistance, and organic solvent resistance.

  The fuel container cap is used as a lid for a fuel filler. The joining method is not particularly limited, but examples thereof include a screw-in type and a fitting type, and a screw-in type is preferable. Currently, many fuel container caps are made of metal, but thermoplastic resin caps have attracted attention in recent years from the viewpoint of weight reduction and recycling. In addition, the filler port is connected to the fuel container body via the filler pipe and the fuel container connector.However, in the past, metal oxide mixed into the fuel container due to rust generated from the metal fuel container cap became a problem. ing. From such a viewpoint, the existence of the cap made of the thermoplastic resin is significant. Such a fuel container cap preferably has excellent gasoline barrier properties, organic solvent resistance, and stress crack resistance, and more preferably has excellent mechanical strength such as abrasion resistance because of repeated opening and closing.

  Further, a fuel container in which a component made of the thermosetting resin (E) is mounted via a molded component on a fuel container main body on which the molded component is mounted is also suitable as an embodiment of the present invention. In the fuel container having the above-described configuration, the component made of the thermosetting resin (E) has mechanical strength and excellent gasoline barrier properties, and the component made of the thermosetting resin (E) is attached to the mounting portion of the fuel container body. By interposing a molded part made of the resin composition of the present invention, it is preferable in that high gasoline barrier properties can be imparted. As the thermosetting resin (E), it is particularly preferable to use a polymethylene oxide-based resin from the viewpoint of mechanical strength, gasoline barrier properties, and the like. The molded part for a fuel container mounted on the fuel container by such a configuration is not particularly limited, but a pressure relief valve for a fuel container is preferable.

  There is no particular limitation on the method by which the component made of the thermosetting resin (E) is mounted on the fuel container via the molded component. First, a molded part is mounted on the fuel container body, and then a fuel container part made of the thermosetting resin (E) is mounted on the molded part by a method such as a screw-in type or a plug-in type. A method of mounting the molded component on a component made of the thermosetting resin (E) and then mounting the molded component on the fuel container body is exemplified, but is not particularly limited.

  The method for mounting the molded part on the fuel container body is not particularly limited. Examples of mounting by screwing, mounting, and mounting by heat fusion are exemplified, but mounting by heat fusion is particularly preferable from the viewpoint of reducing the number of assembly steps and suppressing fuel leakage from the mounting portion.

  There is no particular limitation on the method of attaching the molded component to the component made of the thermosetting resin (E). A screw-in method and a fitting-in method are preferred. Further, a method of coating the joint surface between the component made of the thermosetting resin (E) and the fuel container with the resin composition used in the present invention is also suitable. Since the thermosetting resin (E) and the resin composition used in the present invention generally have low adhesiveness, the surface of the component made of the thermosetting resin (E) must be within a range that does not impair the function of the molded component. It is particularly preferable to coat as much as possible with the resin composition used in the present invention. By employing such a configuration, it is possible to suppress separation at the interface between the molded component body made of the thermosetting resin (E) and the resin composition of the present invention.

  The method of coating the molded component body with the resin composition used in the present invention is not particularly limited, but the component body made of the thermosetting resin (E) previously prepared by the injection molding method or the like is placed in the mold. Then, a method of injecting and coating the resin composition of the present invention with an injection molding machine (insert injection method), or a method of co-injection molding the thermosetting resin (E) and the resin composition used in the present invention. And the like are preferred, and the insert injection method is particularly preferred.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Material used)
Table 1 below shows the resin components used in the production of the molded parts of Examples 1 to 15 and Comparative Examples 1 to 7.

(Synthesis of resin used in the present invention)
(Synthesis example 1)
The boronic acid-modified polyethylene (b-3) (and (c-3)) (high-density polyethylene having a boronic acid ethylene glycol ester group at the terminal) in Table 1 was prepared as follows.

In a separable flask with a cooler, a stirrer and a dropping funnel, high-density polyethylene ｛MFR 0.3 g / 10 min (190 ° C.-load 2160 g) density 0.952 g / cm ³ , terminal double bond amount 0.048 meq / g｝ 1000 g And 2500 g of decalin were charged and degassed by reducing the pressure at room temperature, followed by purging with nitrogen. To this, 78 g of trimethyl borate and 5.8 g of borane-triethylamine complex were added, and after reacting at 200 ° C. for 4 hours, a distillation apparatus was attached and 100 ml of methanol was slowly added dropwise. After completion of the dropwise addition of methanol, low-boiling impurities such as methanol, trimethyl borate, and triethylamine were distilled off by distillation under reduced pressure. Further, 31 g of ethylene glycol was added, and the mixture was stirred for 10 minutes, reprecipitated in acetone, and dried, whereby the amount of boronic acid ethylene glycol ester groups was 0.027 meq / g, and the MFR was 0.3 g / 10 minutes (190 ° C.-load 2160 g). (B-3) (and (c-3)).

(Measurement of fuel permeation amount of used resin)
The measurement of the fuel permeation amount of the barrier resin (A) was performed in the following steps (1) to (5).

(1) BA-055 manufactured by Paxon (density 0.970 g / cm ³ , MFR at 190 ° C.-load 2160 g = 0.03 g / 10 min) as high-density polyethylene (HDPE), and Mitsui Chemicals as adhesive resin (Tie) Using ADMER GT-6AMFR 0.94 g / 10 min (190 ° C.-load 2160 g), high-density polyethylene, barrier resin (A) and adhesive resin were charged into separate extruders, and high-density polyethylene / adhesive resin / A co-extruded sheet with a total thickness of 120 μm having a configuration of barrier resin (A) / adhesive resin / high-density polyethylene (film thickness 50 μm / 5 μm / 10 μm / 5 μm / 50 μm) was obtained by a molding apparatus. Extrusion molding was performed at a temperature of 170 to 210 ° C. with an extruder having a high-density polyethylene of 65 mm in diameter and a single screw of L / D = 24, and an adhesive resin having a single screw of 40 mm in diameter and L / D = 22 mm. The extruder was set to a temperature of 160 to 210 ° C., the barrier resin (A) was set to a temperature of 170 to 210 ° C. for an extruder having a diameter of 40 mm and an L / D = 22 single screw, and a feed block die (600 mm in width) was used. ) Was operated at 210 ° C. to obtain a co-extruded sheet (a1).

(2) One side of the co-extruded sheet (a1) was covered with an aluminum tape (available from FP Kako Co., Ltd., trade name: aluminum seal: gasoline barrier property = 0 g · 20 μm / m ² · day).

  (3) The co-extruded sheet (a1) and the co-extruded sheet (b1) covered with aluminum tape were each cut into a size of 210 mm × 300 mm.

  (4) Each of the cut sheets was bent at the center, and two sides were heat-sealed with a dial 6 so as to have a seal width of 10 mm using a heat sealer T-230 manufactured by Fuji Impulse to produce a pouch.

  (5) Each pouch has Ref. 200 ml of C (toluene / isooctane = 1/1) was filled from the unsealed side, and the input side was heat-sealed so as to have a seal width of 10 mm in the same manner as described above.

  The pouch was left in an explosion-proof constant temperature / humidity chamber (40 ° C.-65% RH), and the weight of the pouch was measured every seven days for three months. This test was performed for each of five co-extrusion pouches without aluminum foil (a2) and five co-extrusion pouches (b2) coated with aluminum tape, and the weight change of the pouch before and after each standing time was read. The fuel permeation amount was calculated from the standing time and the inclination of the weight change amount of the pouch.

  The fuel permeation amount of the co-extruded pouch (a2) without the aluminum tape indicates the sum of the fuel permeation amount from both the pouch surface and the heat seal portion. This shows the amount of fuel permeated from the seal portion.

The amount of permeation from (a2) {-the amount of permeation from (b2)} is taken as the fuel permeation amount of the barrier resin (A), and the permeation amount per 20 μm of the barrier resin (A) layer is converted into a thickness. The fuel permeation amount (g · 20 μm / m ² · day) of the barrier resin (A) was determined.

D. Manufacture of multilayer molded parts 1
(Examples 1 to 7, Comparative Examples 1 and 2)
Examples 1 to 7 show the production of a multilayer molded part including the case where a resin composition of a compatibilizer (C) and a thermoplastic resin (D) is used as a thermoplastic resin (B) layer. This is an example.

Example 1
MFR 0.3 g / 10 min (190 ° C.-load 2160 g), 70 parts by weight of polyethylene (d-1) having a density of 0.952 g / cm ³ , and maleic anhydride-modified polyethylene (c-2) (“Modic H541” manufactured by Mitsubishi Chemical Corporation) ) A blend consisting of 30 parts by weight was obtained by the following method. That is, polyethylene (d-1) having a density of 0.952 g / cm ³ and maleic anhydride-modified polyethylene (c-2) were put into a twin-screw vented extruder, and extruded at 220 ° C. in the presence of nitrogen to form pellets. Was performed to obtain pellets of the resin composition.

  The obtained pellets and EVOH (a-1) having an ethylene content of 32 mol%, a saponification degree of 99.5%, and an MFR of 1.6 g / 10 min (190 ° C.-load of 2160 g) were charged into a co-injection molding machine. A multilayer injection-molded product (connector-like molded product) having the shape shown in FIG. 1 and having two inner layers and three layers each having an inner diameter of 62 mm, an outer diameter of 70 mm, and a height of 40 mm was produced. The layer configuration is (outer) thermoplastic resin (B) layer / EVOH (A) layer / thermoplastic resin (B) layer (inner), and the thickness ratio of each part is (outer) 55/15/30% (inner). ). As shown in FIG. 2, the connector-like molded product is attached to the container body 2, and a pipe 3 is attached to the mouth of the connector-like molded product 1. On the other hand, using the same resin as in Example 1, an EVOH-based multilayer fuel container having the same layer configuration was manufactured.

  In the obtained multi-layer fuel container, two holes having a diameter of 65 mm were made in order to mount a connector, and both the portion and the above-mentioned two-type and three-layer connector-like molded product were melted with a 250 ° C iron plate for 40 seconds. After that, it was press-bonded and thermally fused to obtain a multi-layer fuel container with two connectors. A gasoline barrier property and an adhesive strength were evaluated by the following methods using a multilayer fuel container to which the multilayer injection molded article was fused. Table 2 shows the results.

(1) Gasoline barrier property The obtained multilayer fuel container having two openings was filled with 25 liters of model gasoline (toluene: isooctane = 50/50% by volume). Next, an aluminum plate having a diameter of 80 mm and a thickness of 0.5 mm is firmly adhered to one side of the connector-like molded product with an epoxy adhesive, and then placed in an explosion-proof constant temperature / humidity bath (40 ° C.-65% RH). 60 days later, the weight loss (n = 5) was measured (W). As a control, a multilayer sheet (HDPE / adhesive resin / EVOH (a-1) / adhesive resin / HDPE = 2100/100 /) obtained by using the same resin as that used for the multilayer fuel container in two openings. A fuel container (600/100/1100 μm) was thermally fused in the same manner as the connector (the 1100 μm thick HDPE layer side was thermally fused to the fuel container body), and the weight loss of the model gasoline was measured in the same manner ( w). The gasoline reduction from this connector was calculated from the following equation (1).

  Gasoline decrease from connector = WW (1)

(2) Adhesive strength The connector peripheral portion of the gasoline tank with a connector-like multilayer molded product used for gasoline barrier measurement was cut out at a diameter of 20 cm around the connector. The connector portion of the test piece and the cut fuel container sheet portion were fixed, and the strength at which the fused portion was peeled off was determined using an autograph (AG-500A manufactured by Shimadzu).

(3) Interlaminar shear strength of multilayer product A multilayer flat plate having substantially the same layer configuration as the obtained connector-like molded part was prepared, and the interlayer shear strength was measured. That is, a 100 × 100 × 5 mm (length × width × thickness) thermoplastic resin (B) / EVOH (A) / thermoplastic resin (B) two-layer, three-layer multilayer flat plate (thickness configuration is thermoplastic resin (B ) / EVOH (A) / thermoplastic resin (B) = 2.75 / 0.75 / 1.5 mm). Using the multilayer plate, a test piece was prepared according to JIS K7057, and then the interlayer shear strength was measured. The interlayer shear strength referred to here is the strength when breakage (peeling) occurs between the thermoplastic resin (B) layer and the EVOH (A) layer.

Examples 2-6, Comparative Examples 1-2
The barrier resin (A) (a-1) shown in Table 1, the thermoplastic resin (B) (b-1), (b-2), (b-3), the compatibilizer (C) ( Using connector (c-1), (c-2), (c-3), and thermoplastic resin (D) (d-1), in the configuration shown in Table 2, similarly to Example 12, a connector-like molded product Was prepared and evaluated in the same manner as in Example 1. Table 2 shows the results.

Example 7
Thermoplastic resin (B) ((d-1) / (c-2) = 70/30) shown in Table 1, ethylene content 32 mol%, saponification degree 99.5%, MFR 1.6 g / 10 Minutes (190 ° C.-load 2160 g) of EVOH (a-1) was charged into a two-color molding machine, and a cylindrical two-layer, two-layer, two-layer injection molded product having an inner diameter of 62 mm, an outer diameter of 70 mm, and a height of 40 mm (FIG. 1) Was prepared. The layer configuration was (outer) EVOH (A) layer / thermoplastic resin (B) layer (inner), and the thickness ratio was (A) layer / (B) layer = 15/85%. This multilayer molded product was attached to a fuel container prepared in the same manner as in Example 1 as in Example 12, and the adhesive strength and the interlayer shear strength of the multilayer product were evaluated in the same manner as in Example 12. However, for the measurement of the shear strength, the thickness and the layer configuration of the obtained multilayer injection-molded part were substantially the same as those of the obtained multilayer injection molded part, that is, the resin composition (A) / thermoplastic resin (B) = 0.75 / 4.25 mm. An injection-molded multilayer flat plate was used. Table 2 shows the results. The gasoline barrier properties were evaluated as follows.

(Gasoline barrier properties)
The obtained multilayer fuel container having two openings was filled with 25 liters of model gasoline (toluene: isooctane = 50/50% by volume). Next, an aluminum plate having a diameter of 80 mm and a thickness of 0.5 mm is firmly adhered to one side of the connector-like molded product with an epoxy adhesive, and then placed in an explosion-proof constant temperature / humidity bath (40 ° C.-65% RH). 60 days later, the weight loss (n = 5) was measured (W). As a control, a multi-layer sheet (EVOH (A-1) / adhesive resin / HDPE = 600/100/3300 μm) obtained by using the same resin as the resin used for the multi-layer tank in two openings was heated similarly to the connector. A fused fuel container (the HDPE layer side was thermally fused to the fuel container body) was prepared, and the weight loss of the model gasoline was measured in the same manner (w). The gasoline reduction from this connector was calculated from the following equation (1).

  Gasoline decrease from connector = WW (1)

E. FIG. Production of multilayer molded parts 2
(Examples 8 to 14, Comparative Examples 3 to 7)
Examples 8 to 15 describe the production of a multilayer molded part using a resin composition layer composed of EVOH, a compatibilizer (C) and a thermoplastic resin (D) as a barrier resin (A) layer. It is an embodiment shown.

Example 8
40 parts by weight of EVOH (a-1) having an ethylene content of 32 mol%, a saponification degree of 99.5%, 1.6 g / 10 min (190 ° C.-load 2160 g), an ethylene content of 89 mol%, a saponification degree of 97%, 20 parts by weight of a saponified ethylene-vinyl acetate copolymer (c-1) having an MFR of 5 g / 10 min (190 ° C.-load 2160 g) and a density of 0.952 g / cm of MFR 0.3 g / 10 min (190 ° C.-load 2160 g). ^A resin composition comprising 40 parts by weight of polyethylene (d-1) was obtained by the following method. That is, EVOH (a-1), a saponified ethylene-vinyl acetate copolymer (c-1) having an ethylene content of 89 mol% and a saponification degree of 97 mol%, and a polyethylene (d-1) having a density of 0.952 g / cm ^3. ) Was placed in a twin-screw vented extruder, and extruded at 220 ° C. in the presence of nitrogen to obtain a pellet of the resin composition.

The pellets of the obtained resin composition and polyethylene (b-1) having a density of 0.952 g / cm ³ were charged into a co-injection molding machine, and had an inner diameter of 62 mm, an outer diameter of 70 mm, and a height of 40 mm having the shape shown in FIG. Was produced. The layer configuration was thermoplastic resin (B) layer / resin composition (A) layer / thermoplastic resin (B) layer, and the thickness ratio was (outside) 15/70/15% (inside). This multilayer molded part (connector) is mounted on the multilayer fuel container obtained in the same manner as in Example 1 to obtain a multilayer fuel container with a connector. The adhesive strength and the interlayer of the multilayer product are obtained in the same manner as in Example 12. The shear strength was evaluated.

  However, in the measurement of the shear strength, almost the same layer constitution as that of the obtained multilayer injection-molded part was used, that is, the thermoplastic resin (B) / the resin composition (A) / the thermoplastic resin (B) = 0.75 / 3. An injection-molded multilayer flat plate having a thickness and a layer configuration of 0.5 / 0.75 mm was used. The gasoline barrier properties were evaluated as follows.

(Gasoline barrier properties)
The obtained multilayer fuel container having two openings was filled with 25 liters of model gasoline (toluene: isooctane = 50/50% by volume). Next, an aluminum plate having a diameter of 80 mm and a thickness of 0.5 mm is firmly adhered to one side of the connector-like molded product with an epoxy adhesive, and then placed in an explosion-proof constant temperature / humidity bath (40 ° C.-65% RH). 60 days later, the weight loss (n = 5) was measured (W). As a control, a multilayer sheet (HDPE / adhesive resin / EVOH (a-1) / adhesive resin / HDPE = 400/200 /) obtained by using the same resin as the resin used for the multilayer fuel container in two openings. 2800/200/400 μm) was prepared by heat-sealing the same as the connector, and the weight loss of the model gasoline was measured in the same manner (w). The gasoline reduction from this connector was calculated from the following equation (1).

  Gasoline decrease from connector = WW (1)

Examples 9 to 13 and Comparative Examples 3 to 7
The barrier resins (A) (a-1), thermoplastic resins (B) (b-1), compatibilizers (C) (c-1), (c-2), (c) -3) and a thermoplastic resin (D) (d-1) were used to produce a connector-like molded product in the same manner as in Example 5 with the configuration shown in Table 3, and evaluated in the same manner as in Example 8. Table 3 shows the results.

Example 14
The resin composition (A) ((a-1) / (c-1) / (d-1) = 40/20/40) shown in Table ^{3 and} a polyethylene (b-) having a density of 0.952 g / cm ³ were used. 1) was charged into a two-color molding machine, respectively, to produce a two-layer, two-layer cylindrical injection molded product (FIG. 1) having an inner diameter of 62 mm, an outer diameter of 70 mm, and a height of 40 mm. The layer configuration was (outer) resin composition (A) layer / thermoplastic resin (B) layer (inner), and the thickness ratio was (A) layer / (B) layer = 70/30%. This multilayer molded product was attached to a fuel container and a pipe in the same manner as in Example 8. The same fuel container as in Example 8 was used for the evaluation, and the adhesive strength and the interlayer shear strength of the multilayer product were evaluated in the same manner as in Example 1. However, in the measurement of the shear strength, the layer configuration almost the same as that of the obtained multilayer injection molded part, that is, the resin composition (A) / thermoplastic resin (B) = 2.8 / 1.2 mm thickness and layer configuration An injection-molded multilayer plate having the following characteristics was used. Table 6 shows the results. The gasoline barrier properties were evaluated as follows.

(Gasoline barrier properties)
The obtained multilayer fuel container having two openings was filled with 25 liters of model gasoline (toluene: isooctane = 50/50% by volume). Next, an aluminum plate having a diameter of 80 mm and a thickness of 0.5 mm is firmly adhered to one side of the connector-like molded product with an epoxy adhesive, and then placed in an explosion-proof constant temperature / humidity bath (40 ° C.-65% RH). 60 days later, the weight loss (n = 5) was measured (W). As a control, a multi-layer sheet (EVOH (a-1) / adhesive resin / HDPE = 2800/100/1100 μm) obtained by using the same resin as the resin used for the multi-layer fuel container in two openings was similarly used for the connector. A heat-sealed fuel container (heat-sealing the HDPE layer side to the fuel container body) was prepared, and the weight loss of the model gasoline was measured in the same manner (w). The gasoline reduction from this connector was calculated from the following equation (1).

  Gasoline decrease from connector = WW (1)

  The multilayer molded article mounted on the fuel container of the present invention obtained in Examples 8 to 14 was excellent in gasoline barrier properties and heat fusion properties, and had sufficient mechanical strength. Among them, Examples 8, 11 and 11 using saponified ethylene-vinyl acetate copolymer (c-1) having an ethylene content of 89 mol% and a saponification degree of 97 mol% as the compatibilizer (C). In No. 14, the gasoline barrier property was remarkably improved.

  On the other hand, in Comparative Examples 3 and 4 in which the content of EVOH contained in the resin composition (A) layer exceeds 80% by weight, the interlayer between the resin composition (A) layer and the thermoplastic resin (B) layer was used. The shear strength was unsatisfactory, and the mechanical strength was poor. In Comparative Example 5 in which the content of EVOH contained in the resin composition (A) layer was less than 10% by weight, the gasoline barrier properties were unsatisfactory. In Comparative Example 6 in which the molded article was composed of a single layer of polyethylene, the gasoline barrier property was insufficient, and in Comparative Example 7 in which the molded article was composed of only EVOH, sufficient heat fusion with the fuel container body could not be obtained. Was.

  INDUSTRIAL APPLICABILITY The fuel container of the present invention is a fuel container equipped with a molded part having excellent gasoline barrier properties, heat sealability, mechanical strength, and the like, and can be used in a wide range of fields such as fuel containers for automobiles.

It is a figure which shows the cylindrical molded product (connector-like molded product) shape | molded by the multilayer injection molding machine. It is a figure which shows the usage form of the molded article for connectors.

Explanation of reference numerals

1: Molded product like connector 2: Container body 3: Pipe

Claims (16)

  A barrier resin (A) layer having a solubility parameter (calculated from the Fedors equation) exceeding 11 and a thermoplastic resin (B) layer having a solubility parameter (calculated from the Fedors equation) of 11 or less are laminated. A fuel container having a molded part attached to a fuel container body.   A multilayer comprising a barrier resin (A) layer in which the barrier resin (A) layer is at least one selected from the group consisting of a polyvinyl alcohol-based resin, a polyamide, and an aliphatic polyketone; and a thermoplastic resin (B) layer. The fuel container according to claim 1, which is a molded part.   The fuel container according to claim 2, wherein the barrier resin (A) comprises an ethylene-vinyl alcohol copolymer (A1) having an ethylene content of 5 to 60 mol% and a saponification degree of 85% or more.   The barrier resin (A) layer has an ethylene-vinyl alcohol copolymer of 10 to 80% by weight, a compatibilizer (C) of 1 to 90% by weight, and a dissolution of 11 or less other than (A) and (C). The fuel container according to claim 3, which is a resin composition comprising a thermoplastic resin (D) having a sex parameter (calculated from the Fedors equation) from 0 to 89% by weight.   The compatibilizer (C) is selected from the group consisting of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, a carboxylic acid-modified polyolefin, and a boronic acid-modified polyolefin. The fuel container according to claim 4, wherein   The fuel container according to any one of claims 2 to 5, wherein the thermoplastic resin (B) layer is a polyolefin-based resin. The thermoplastic resin (B) layer is made of a density 0.93 g / cm ³ or more polyethylene fuel container according to claim 6.   The thermoplastic resin (B) layer is selected from the group consisting of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, a carboxylic acid-modified polyolefin, and a boronic acid-modified polyolefin. The fuel container according to claim 6, wherein   The thermoplastic resin (B) layer is selected from the group consisting of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 70 to 99 mol% and a saponification degree of 40% or more, a carboxylic acid-modified polyolefin, and a boronic acid-modified polyolefin. From 1 to 99% by weight of at least one compatibilizer (C) and from 1 to 99% by weight of a thermoplastic resin (D) having a solubility parameter of less than 11 other than (C) (calculated from the Fedors equation). The fuel container according to claim 6, which is a resin composition comprising:   The fuel container according to any one of claims 1 to 9, wherein at least one of the barrier resin (A) layer and the thermoplastic resin (B) layer contains 1 to 50% by weight of an inorganic filler.   The fuel container according to any one of claims 1 to 10, wherein the molded part is molded by a multilayer injection molding machine.   The fuel container according to any one of claims 1 to 11, wherein the molded component is mounted on a fuel container main body via a thermoplastic resin (B) layer.   The fuel container according to any one of claims 1 to 12, wherein the molded part is a fuel container connector, a fuel container cap, or a fuel container valve.   The fuel container according to any one of claims 1 to 13, wherein the molded component is mounted on the fuel container body by heat fusion.   15. A fuel container having a molded part according to any one of claims 1 to 14 mounted thereon with a part made of a thermosetting resin (E) via the molded part.   The fuel container according to claim 15, wherein the thermosetting resin (E) is polymethylene oxide.

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