JP2006088694A - Method for producing hollow molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for producing a hollow molded body such as a fuel container which is easy to manufacture with simple equipment and has excellent fuel barrier properties.
A method for producing a hollow molded body comprising a step of joining and integrating two or more members at a peripheral portion of the member, wherein at least one of the members is formed on one side of a thermoplastic polymer resin sheet. Alternatively, a method for producing a hollow molded body, wherein a fuel barrier coating is formed on both sides to form a fuel barrier layer, followed by pressure forming or vacuum forming.
[Selection] None

Description

  The present invention relates to a method for manufacturing a hollow molded body such as a fuel container for storing fuel such as gasoline.

  Conventionally, as a fuel tank used for automobiles, from the viewpoint of strength, etc., a metal fuel tank manufactured by press working and welding of an iron plate or the like, or synthetic resin blown from the viewpoint of workability, etc. Molded synthetic resin fuel tanks have been used. In particular, a fuel tank made of a thermoplastic polymer resin has been used in order to reduce the weight of the vehicle and improve the degree of freedom of design.

  However, when manufacturing a large fuel tank by this blow molding, when the heated and fluidized parison is put into the mold from the top of the molding machine, the upper wall thickness becomes thinner than the lower wall wall thickness. In some cases, the thickness cannot be uniform. Also, if the shape of the fuel tank is large or complex, when the parison is expanded in the mold, the rate of expansion of the parison may vary depending on the part of the product, and the product thickness varies. There was a case. Therefore, it is difficult to control the thickness of the product, and in order to satisfy the performance such as the tank strength, the entire thickness of the product has to be increased, and the weight of the fuel tank is increased. In addition, since the parison is sandwiched between molds in blow molding, relatively large burrs are generated, material is wasted, and productivity is not good.

  Further, in blow molding, since the parison is expanded in the mold, there is a restriction in disposing devices such as a fuel pump unit and a float in the fuel tank. For this reason, there is a type in which a fuel tank is manufactured by separately molding an upper part and a lower part of a fuel tank using a mold and joining the separately molded parts (see Patent Document 1).

  On the other hand, the fuel tank is required to have a fuel barrier property that does not allow fuel or the like to permeate to protect the global environment. Therefore, conventionally, in order to prevent fuel such as gasoline from permeating, a barrier layer is formed by first setting a film having a fuel barrier property on a mold and then forming it into the shape of a fuel tank by vacuum forming. Then, the fuel tank was manufactured by injection molding the thermoplastic polymer resin constituting the base material layer so that the barrier layer became the inner surface of the fuel tank. However, the film of the barrier layer may be stretched during injection molding, and there is a possibility that sufficient barrier properties cannot be obtained. In addition, the adhesion and bonding properties between the barrier layer film and the thermoplastic polymer resin constituting the base material layer may not be sufficient. Furthermore, it may be difficult to spread the fuel barrier sheet to the end of all the peripheral portions without leakage, and the fuel barrier property is not sufficient.

  Also, a pair of molds for molding the fuel tank divided into two parts are provided, and after the divided parts are molded by injection molding with each mold, the molds are slid to butt each other. In addition, a manufacturing method is also introduced in which molten resin is injected to the periphery of the mated surfaces and the divided bodies are fused to each other (see Patent Document 2). However, with this method, the equipment for sliding the mold is complicated and expensive.

  Furthermore, as a method of manufacturing a fuel tank in which the parts constituting the fuel tank divided into two parts are joined together at the peripheral edge of each divided opening, a thermoplastic polymer resin having low fuel permeability is injection molded or injected. A method of forming by compression molding has been introduced (see Patent Document 3).

Japanese Patent Laid-Open No. 10-157738 JP 2001-129851 A JP 2004-98886 A

  An object of the present invention is to manufacture a hollow molded body such as a fuel container that is easy to manufacture with simple equipment and has excellent fuel barrier properties in consideration of such facts, and is hollow such as a lightened fuel container. The object is to produce a molded body.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention applied a fuel barrier coating to a thermoplastic polymer resin sheet in advance to produce a fuel barrier layer when manufacturing a hollow molded body such as a fuel container. After forming, by using a member obtained by molding the sheet, it was found that a hollow molded body that was easy to manufacture and excellent in fuel barrier properties was obtained, and the present invention was achieved.
That is, the present invention is a method for producing a hollow molded body comprising a step of joining and integrating two or more members at the peripheral edge of the member, wherein at least one of the members is made of a thermoplastic polymer resin sheet. The present invention relates to a method for manufacturing a hollow molded body, wherein a fuel barrier layer is formed on one side or both sides by forming a fuel barrier layer and then manufactured by pressure forming or vacuum forming.

  The present invention can provide a method for producing a hollow molded body such as a fuel container having a high fuel barrier property at a low cost and in a simple manner.

In the present invention, the hollow molded body is a fuel container mounted on automobiles, motorcycles, ships, aircraft, generators and industrial and agricultural equipment, a fuel container for replenishing fuel, and further used for these operations. It is a generic term for fuel containers for storing fuel, and hoses, pipes, tubes, cocks, joints, etc. associated with these fuel containers.
Typical examples of the fuel include gasoline and gasoline blended with methanol, ethanol or MTBE, that is, oxygen-containing gasoline, but other heavy oils, light oils, kerosene and the like are also exemplified.

In the present invention, the resin used in the sheet may be any thermoplastic polymer resin, and may be a mixture of two or more thermoplastic polymer resins. The sheet may be either a single layer or a multilayer composed of a thermoplastic polymer resin and / or a mixture thereof. The thickness of the thermoplastic resin sheet is preferably 0.1 to 50 mm, more preferably 0.5 to 40 mm, and still more preferably 1 to 30 mm.
Thermoplastic polymer resins include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and polyamide resins such as nylon 6, nylon 6,6, and polymetaxylylene adipamide (N-MXD6). Examples include resins, polyacrylonitrile resins, poly (meth) acrylic resins, polystyrene resins, polycarbonate resins, saponified ethylene-vinyl acetate copolymers (EVOH) resins, and polyvinyl alcohol resins. Examples of the adhesive polyolefin resin include a polymer resin obtained by modifying polyethylene or polypropylene with maleic anhydride or the like. However, those using polyethylene are preferred from the viewpoints of economy, moldability, mechanical strength, etc., and a polyethylene single layer is particularly preferred.

Fuel barrier coating material used in the present invention preferably has fuel permeability coefficient at 60 ° C. of the fuel barrier layer obtained from the coating material is ^{2 (g · mm / m 2} · day) or less. More preferably, it is 1 (g · mm / m ² · day) or less, and particularly preferably 0.5 (g · mm / m ² · day) or less. If it exceeds 2 (g · mm / m ² · day), the fuel will permeate without increasing the fuel barrier layer thickness, which increases the amount of paint applied and makes it difficult to control the layer thickness. Economic problems arise.
The fuel barrier layer preferably contains 40 to 98% by weight of the skeleton structure of the formula (1). Further, it is preferably contained in an amount of 50 to 90% by weight, particularly 55 to 80% by weight.

  The fuel barrier paint used in the present invention is preferably a paint comprising an epoxy resin and an epoxy resin curing agent capable of forming a fuel barrier layer at a relatively low temperature.

  The epoxy resin may be any of an aliphatic compound, an alicyclic compound, an aromatic compound, or a heterocyclic compound, but in consideration of the expression of high fuel barrier properties, the aromatic moiety is in the molecule. The epoxy resin containing is preferable, and the epoxy resin containing the skeleton structure of the formula (1) in the molecule is more preferable. Specifically, an epoxy resin having a glycidylamine moiety derived from metaxylylenediamine, an epoxy resin having a glycidylamine moiety derived from 1,3-bis (aminomethyl) cyclohexane, and a glycidylamine derived from diaminodiphenylmethane An epoxy resin having a glycidylamine moiety and / or a glycidyl ether moiety derived from paraaminophenol, an epoxy resin having a glycidyl ether moiety derived from bisphenol A, and a glycidyl ether moiety derived from bisphenol F Epoxy resin having glycidyl ether moiety derived from phenol novolac, epoxy resin having glycidyl ether moiety derived from resorcinol Fats can be used, but among them, epoxy resin having glycidylamine moiety derived from metaxylylenediamine, epoxy resin having glycidylamine moiety derived from 1,3-bis (aminomethyl) cyclohexane, derived from bisphenol F Preferred are epoxy resins having a glycidyl ether moiety and epoxy resins having a glycidyl ether moiety derived from resorcinol.

  Further, it is more preferable to use an epoxy resin having a glycidyl ether moiety derived from bisphenol F or an epoxy resin having a glycidyl amine moiety derived from metaxylylenediamine as a main component, and derived from metaxylylenediamine. It is particularly preferable to use an epoxy resin having a glycidylamine moiety as a main component.

  Moreover, in order to improve various performances such as flexibility, impact resistance, and moist heat resistance, the above-mentioned various epoxy resins can be mixed and used at an appropriate ratio.

  The epoxy resin can be obtained by reaction of various alcohols, phenols and amines with epihalohydrin. For example, an epoxy resin having a glycidylamine moiety derived from metaxylylenediamine can be obtained by adding epichlorohydrin to metaxylylenediamine. The glycidylamine moiety comprises a mono-, di-, tri- and / or tetra-glycidylamine moiety that can replace the four hydrogen atoms of the diamine in xylylenediamine. The ratio of mono-, di-, tri- and / or tetra-glycidylamine moieties can be varied by changing the reaction ratio of metaxylylenediamine to epichlorohydrin. For example, an epoxy resin mainly having a tetraglycidylamine moiety can be obtained by addition reaction of about 4 times mole of epichlorohydrin to metaxylylenediamine.

The epoxy resin is an excess of epihalohydrin with respect to various alcohols, phenols and amines in the presence of an alkali such as sodium hydroxide, 20 to 140 ° C., preferably 50 to 120 ° C. in the case of alcohols and phenols, amine In the case of a kind, it is synthesized by reacting at a temperature of 20 to 70 ° C. and separating the produced alkali halide.
The number average molecular weight of the produced epoxy resin varies depending on the molar ratio of epihalohydrin to various alcohols, phenols and amines, but is about 80 to 4000, preferably about 200 to 1000, preferably about 200 to 500. It is more preferable.

The epoxy resin curing agent may be an aliphatic compound, an alicyclic compound, an aromatic compound, or a heterocyclic compound, and is generally used as a polyamine, a phenol, an acid anhydride, or a carboxylic acid. Epoxy resin curing agents that can be used can be used. These epoxy resin curing agents can be selected according to the required degree of fuel barrier properties.
Specifically, polyamines include aliphatic amines such as ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine, aliphatic amines having an aromatic ring such as metaxylylenediamine and paraxylylenediamine, 1,3- Examples include alicyclic amines such as bis (aminomethyl) cyclohexane, isophoronediamine, norbornanediamine, and aromatic amines such as diaminodiphenylmethane and metaphenylenediamine.
Also, reaction products with epoxy resins or monoglycidyl compounds made from these polyamines, reaction products with alkylene oxides having 2 to 4 carbon atoms, reaction products with epichlorohydrin, these polyamines A reaction product with a polyfunctional compound having at least one acyl group capable of forming an amide group site by reaction with, an oligomer with an amide group site formed by reaction with these polyamines A reaction product of a polyfunctional compound having at least one acyl group and a monovalent carboxylic acid and / or a derivative thereof can be used.

  Examples of phenols include polyphenols such as catechol, resorcinol and hydroquinone, and resole type phenol resins. Acid anhydrides or carboxylic acids include aliphatic acid anhydrides such as dodecenyl succinic anhydride and polyadipic anhydride, and alicyclic acid anhydrides such as (methyl) tetrahydrophthalic anhydride and (methyl) hexahydrophthalic anhydride. Aromatic acid anhydrides such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and carboxylic acids thereof can be used.

  In consideration of the expression of high fuel barrier properties, an epoxy resin curing agent containing an aromatic moiety in the molecule is preferable, and an epoxy resin curing agent including the skeleton structure of the formula (1) in the molecule is more preferable. Specifically, metaxylylenediamine or paraxylylenediamine, reaction products with epoxy resins or monoglycidyl compounds using these as raw materials, reaction products with alkylene oxides having 2 to 4 carbon atoms, epichlorohydrin A reaction product with a polyfunctional compound having at least one acyl group capable of forming an amide group site by reaction with metaxylylenediamine and / or paraxylylenediamine to form an oligomer, Polyfunctional compound having at least one acyl group and monovalent carboxylic acid and / or derivative thereof capable of forming an amide group site and forming an oligomer by reaction with metaxylylenediamine and / or paraxylylenediamine It is more preferable to use a reaction product with

In consideration of high fuel barrier properties and good adhesion to a thermoplastic polymer resin sheet, the following reaction products (A) and (B), or (A), (B ) And (C) are particularly preferred.
(A) Metaxylylenediamine or paraxylylenediamine
(B) A polyfunctional compound having at least one acyl group capable of forming an amide group site by reaction with metaxylylenediamine or paraxylylenediamine to form an oligomer
(C) C1-C8 monovalent carboxylic acid and / or derivative thereof

  Examples of the polyfunctional compound having at least one acyl group (B) include acrylic acid, methacrylic acid, maleic acid, fumaric acid, succinic acid, malic acid, tartaric acid, adipic acid, isophthalic acid, terephthalic acid, pyromellitic Examples thereof include carboxylic acids such as acids and trimellitic acids and derivatives thereof, such as esters, amides, acid anhydrides, acid chlorides, etc., and acrylic acid, methacrylic acid and derivatives thereof are particularly preferable.

Examples of (C) include formic acid, acetic acid, propionic acid, butyric acid, lactic acid, glycolic acid, benzoic acid and derivatives thereof such as esters, amides, acid anhydrides, acid chlorides and the like.
The amide group site has a high cohesive force, and the presence of the amide group site in a high proportion in the epoxy resin curing agent provides higher fuel barrier properties and better adhesion strength to the thermoplastic polymer resin sheet. It is done.

  The reaction molar ratio of (A) and (B) or (A), (B), and (C) is the reactive functionality contained in (B) with respect to the number of amino groups contained in (A). The ratio of the number of groups, or the ratio of the total number of reactive functional groups contained in (B) and (C) to the number of amino groups contained in (A) is in the range of 0.3 to 0.97 Is preferred. When the ratio is less than 0.3, a sufficient amount of amide groups are not formed in the epoxy resin curing agent, and a high level of fuel barrier property and adhesion to the thermoplastic polymer resin sheet are not exhibited. Moreover, the ratio of the volatile molecule which remains in the epoxy resin curing agent is increased, which causes odor generation from the obtained cured product. In addition, since the ratio of the hydroxyl group produced by the reaction between the epoxy group and the amino group in the cured reaction product becomes high, the fuel barrier property in a high humidity environment is significantly reduced. On the other hand, in the range higher than 0.97, the amount of amino groups reacting with the epoxy resin is reduced, and excellent impact resistance and heat resistance are not exhibited, and the solubility in various organic solvents or water is lowered. When particularly considering the high fuel barrier property, high adhesion, suppression of odor generation, and high fuel barrier property in a high humidity environment of the obtained cured product, the reaction molar ratio is 0.6 to 0.97. A range is more preferred. When considering the expression of adhesion to a higher level thermoplastic polymer resin sheet, the epoxy resin curing agent in the present invention contains at least 6% by weight of amide groups based on the total weight of the curing agent. Preferably, 6 to 30% by weight is more preferable. As the epoxy resin curing agent used in the present invention, a reaction product of metaxylylenediamine and acrylic acid, methacrylic acid and / or a derivative thereof is particularly preferable.

As a method for coating the thermoplastic polymer resin sheet, any of commonly used coating types such as dip coating, spray coating, brush coating, roll coating or flow coating can be used.
The coating on the thermoplastic polymer resin sheet is performed at a concentration and temperature of the fuel barrier coating material sufficient to obtain an epoxy resin cured product that becomes a fuel barrier layer, and this is applied to the epoxy resin, the epoxy resin curing agent and the coating. It can vary depending on the choice of method. That is, the concentration of the fuel-barrier coating is about from using no appropriate solvent depending on the type and weight ratio of the epoxy resin to the epoxy resin curing agent, the coating method, etc., and using some appropriate organic solvent and / or water. Various states up to the case of dilution to a concentration of about 5% by weight (total amount of epoxy resin and epoxy resin curing agent) can be taken. The blending ratio of the epoxy resin and the epoxy resin curing agent in the fuel barrier coating is preferably 0.3 to 20 as a ratio (equivalent ratio) of the number of active hydrogens of the epoxy resin curing agent to the number of epoxy groups of the epoxy resin. 0.5 to 10 is more preferable, and 0.8 to 5 is still more preferable. Suitable organic solvents include solvents such as toluene, xylene, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-butoxyethanol, 1-methoxy-2- Glycol ethers such as propanol, 1-ethoxy-2-propanol and 1-propoxy-2-propanol, alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol and 2-butanol, N, N And aprotic polar solvents such as -dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone and the like. These can be used alone or as a mixed solvent of two or more.

  In the present invention, after the coating, the coating amount can be adjusted, the appearance can be made uniform, and the layer thickness can be made uniform by an air knife method or a roll drawing method.

  When a fuel barrier coating is applied to the surface of the thermoplastic polymer resin sheet, a wetting agent such as silicon or an acrylic compound is added to the coating to help wet the thermoplastic polymer resin sheet. Also good. Suitable wetting agents include BYK331, BYK333, BYK348, BYK381 available from Big Chemie. When adding these, the range of 0.01 to 2 weight% is preferable on the basis of the solid content of a fuel barrier coating.

  In addition, in order to improve various properties such as fuel barrier properties, impact resistance, heat resistance, etc. of the fuel barrier layer in the present invention, silica, alumina, mica, talc, aluminum flakes, glass flakes, etc. in the fuel barrier coating An inorganic filler may be added. In view of high fuel barrier properties, such inorganic fillers are preferably flat. When adding these, the range of 0.01 weight%-10 weight% is preferable on the basis of the solid content weight of a fuel-barrier coating material.

  Furthermore, in order to improve the adhesion of the fuel barrier layer used in the present invention to the surface of the thermoplastic polymer resin sheet, a coupling agent such as a silane coupling agent or a titanium coupling agent is added to the fuel barrier coating. You may do it. When adding these, the range of 0.01 weight%-5 weight% is preferable on the basis of the total weight of a fuel-barrier coating material.

  Further, the fuel-barrier coating used in the present invention includes a accelerating catalyst such as N-ethylmorpholine, dibutyltin dilaurate, cobalt naphthenate, stannous chloride, benzyl, etc. Organic solvents such as alcohol, zinc phosphate, iron phosphate, calcium molybdate, vanadium oxide, water-dispersed silica, fumed silica, and other anti-rust additives, phthalocyanine organic pigments, condensed polycyclic organic pigments, and other organic pigments In addition, each component such as an inorganic pigment such as titanium oxide, zinc oxide, calcium carbonate, barium sulfate, alumina, or carbon black may be added in a necessary proportion.

  The thickness of the fuel barrier layer obtained from the fuel barrier coating material in the present invention is about 1 to 500 μm, preferably 3 to 300 μm, more preferably 5 to 200 μm. If it is less than 1 μm, defects in the fuel barrier layer tend to occur, and if it exceeds 500 μm, it is difficult to control the layer thickness.

  In the present invention, after coating the fuel barrier coating material on the surface of the thermoplastic polymer resin sheet, the sheet is formed into a member constituting a hollow molded body by vacuum forming and / or pressure forming. The fuel barrier coating is cured before molding.

The curing temperature for curing the fuel barrier layer after coating the fuel barrier coating on the surface of the thermoplastic polymer resin sheet in the present invention is preferably 0 to 150 ° C, more preferably 10 to 100 ° C, still more preferably. Is 20-80 ° C. If it exceeds 150 ° C., the thermoplastic polymer resin is deformed by heat, which is not preferable.

  The curing time for curing the fuel barrier layer to such an extent that dust or dust floating in the air does not contaminate the fuel barrier layer after coating the fuel barrier coating on the surface of the thermoplastic polymer resin sheet in the present invention is preferably Is 1 to 60 minutes, more preferably 3 to 20 minutes, still more preferably 5 to 10 minutes. When the curing time exceeds 60 minutes, productivity is lowered, which is not preferable.

  In the present invention, after coating the fuel barrier coating on the surface of the thermoplastic polymer resin sheet, the heating apparatus used for curing to form the fuel barrier layer is a dryer, high frequency induction heating, far infrared heating, gas heating. The method can be appropriately selected from conventionally known methods.

  When coating a fuel barrier coating on the surface of a thermoplastic polymer resin sheet, in order to improve the adhesion between the fuel barrier layer formed from the coating and the sheet, a surface treatment is applied to the surface of the sheet in advance. Can be kept. As the surface treatment method, any surface treatment can be used, but from the viewpoint of ease of treatment and productivity, corona treatment, flame treatment, plasma treatment, UV treatment, chemical treatment or primer treatment is preferable, or a combination thereof. Also good.

  A protective layer may be further formed on the surface of the fuel barrier layer. The protective layer may be any protective layer as long as the fuel barrier layer can be protected, and the protective layer may be formed by any method. Further, the protective layer may be one or more layers, and the protective layer forming method may be a combination of various methods.

If a protective layer forms a protective layer by coating, the protective layer by the coating film formed with the epoxy resin coating material, the urethane resin coating material, the polyester resin coating material, the acrylic resin coating material etc. can be illustrated.
If the protective layer is formed by a film or sheet, polyolefin resin such as low density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, polyester resin such as polyethylene terephthalate or polybutylene terephthalate, nylon 6 , Nylon 6,6, polyamide resin such as metaxylene adipamide (N-MXD6), polyacrylonitrile resin, poly (meth) acrylic resin, polystyrene resin, polycarbonate resin, ethylene-vinyl acetate copolymer Examples include saponified (EVOH) -based resins, polyvinyl alcohol-based resin films and sheets, papers such as cartons, and protective layers made of metal foils such as aluminum and copper.

  The hollow molded body of the present invention is obtained by joining and integrating two or more members at the peripheral edge of the members. At least one of the members is obtained by pressure forming and / or vacuum forming after previously forming a fuel barrier layer by coating a fuel barrier paint on at least one surface of the thermoplastic polymer resin sheet. It is. Here, a fuel barrier layer is formed on the surface of the thermoplastic polymer resin sheet that becomes the inner surface of the hollow molded body (surface in contact with the fuel) when bonded. From the viewpoint of fuel barrier properties, a fuel barrier paint is applied to the thermoplastic polymer resin sheet so that a wide area of the inner surface of the hollow molded body is covered with the fuel barrier layer. Moreover, you may use together a metal thing etc. as a member. The sheet may be formed by either pressure forming or vacuum forming, or by pressure air forming.

  In manufacturing the hollow molded body, any method may be used for joining the peripheral portions of the respective members as long as the fuel does not leak. For example, the peripheral portions are heat-sealed. It is possible to show a method of joining with a molten resin, fastening with a screw or the like, or using an adhesive, and one or more of these may be joined in combination. Moreover, the junction part may be uneven | corrugated shape which mutually bites, and there is no restriction | limiting in the shape. Further, if necessary, the fuel barrier layer may be formed by coating the fuel barrier coating on the inner surface and outer surface of the joined hollow molded body.

Examples of the present invention are introduced below, but the present invention is not limited to these examples.
The evaluation method of the barrier layer is as follows.
<Measurement method of fuel permeability coefficient of barrier layer>
20ml of fuel (FuelC (ASTM D 471) 90 (vol%) + ethanol 10 (vol%)) is put in an aluminum cup with a flange (opening 38mmφ, content 25ml), and fuel barrier coating is applied by applying fuel barrier paint. A thermoplastic polymer resin sheet with a fuel barrier layer on the aluminum cup so that the fuel barrier layer is on the fuel side, and a thermoplastic polymer resin sheet with a 38mmφ hole with a fuel barrier layer formed on an aluminum flange lid The thickness of the thermoplastic polymer resin sheet on which the fuel barrier layer was formed was determined from the fuel permeation area and the fuel permeation time. 1 mm in length, 1 m ^{2 of} fuel permeation area, and the amount of fuel volatilization (g) per day are calculated. Similarly, to calculate a thermoplastic polymer resin sheet thermoplastic polymer resin sheet 1mm thick also for the fuel barrier layer is not formed, 1 m ^2, and day of the fuel vaporization amount (g). Using these values, the fuel permeability coefficient is calculated from the following equation.
K ₁ = a / ((a + b) / K−b / K ₂ )
a: Thickness (mm) of the fuel barrier layer of the thermoplastic polymer resin sheet on which the fuel barrier layer is formed, b: Thickness (mm) of the thermoplastic polymer resin sheet on the thermoplastic polymer resin sheet on which the fuel barrier layer is formed, K: the thickness of the thermoplastic polymer resin sheet on which the fuel barrier layer is formed 1 mm, the permeation area 1 m ² , and the amount of fuel volatilization per day (g), K ₁ (the fuel permeation coefficient of the fuel barrier layer, g · mm) / M ² · day): fuel barrier layer thickness of thermoplastic polymer resin sheet 1 mm, 1 m ² , fuel volatilization amount per day (g), K ₂ (fuel permeability coefficient of thermoplastic polymer resin sheet, g Mm / m ² · day): the thickness of the thermoplastic polymer resin sheet 1 mm, 1 m ² , and the amount of fuel volatilized per day (g),
<Adhesiveness of barrier layer>
The adhesion between the sheet surface and the fuel barrier layer was evaluated by a cross cut test (JIS K 5600-5-6).

<Example 1>
A polyethylene sheet (fuel permeation coefficient: 250 g · mm / m ² · day) is subjected to a 30-second surface treatment using a UV surface treatment machine (Kasuga Electric PL16-110), and a polyethylene sheet with a thickness of 2 mm The surface wetting tension was 45 mN / m. An epoxy resin having a glycidylamine moiety derived from metaxylylenediamine as an epoxy resin (manufactured by Mitsubishi Gas Chemical Co., Ltd .; TETRAD-X) is used as the epoxy resin curing agent on the surface of the surface-treated sheet. A reaction product obtained by reacting 0.93 mol of methyl acrylate with 1 mol of xylylenediamine was used, and these were compounded at 1.0 as the ratio (equivalent ratio) of the number of active hydrogens of the epoxy resin curing agent to the number of epoxy groups of the epoxy resin. The fuel barrier paint made from the above was applied by spray painting. A member (100mm x 200mm x 50mm) is made from the sheet by pressure air vacuum forming so that the painted surface is inside the tank, and then cured at 60 ° C for 10 minutes, and a fuel barrier layer (fuel) with a thickness of about 20μm A permeability coefficient of 0.1 g · mm / m ² · day, containing 58% by weight of the skeleton structure of the formula (1)) was formed, and a flange was provided. Table 1 shows the adhesion results between the sheet surface and the fuel barrier layer.
On the other hand, two members with a fuel barrier layer formed in the same manner, 150 g of fuel (FuelC (ASTM D 471) 90 (vol%) + ethanol 10 (vol%)) are put in one member, The tank was filled with fuel by tightening the members and screws and joining the flanges and sealing them. The amount of fuel volatilization at 60 ° C. was measured to evaluate the fuel barrier property. The results are shown in Table 1.

<Example 2>
Example 1 except that the surface treatment was performed at a moving speed of 10 m / min using a plasma surface treatment apparatus (PS-601S manufactured by Kasuga Denki Co., Ltd.) and the wetting tension of the polyethylene sheet surface was 76 mN / m. Members and tanks were produced in the same manner, and the adhesion and fuel barrier properties were evaluated. The results are shown in Table 1.

<Example 3>
A member and a member were prepared in the same manner as in Example 1 except that the surface treatment was performed at a moving speed of 50 m / min using a frame surface treatment apparatus (manufactured by Arcogas) and the wetting tension of the polyethylene sheet surface was 50 mN / m. Tanks were prepared and evaluated for adhesion and fuel barrier properties. The results are shown in Table 1.

<Example 4>
Members and tanks were prepared in the same manner as in Example 1 except that the curing condition of the fuel barrier coating was changed to 10 minutes / 100 ° C., and the adhesion and fuel barrier properties were evaluated. The results are shown in Table 1.

<Example 5>
Members and tanks were prepared in the same manner as in Example 1 except that non-surface-treated nylon 6,6 sheets (wet tension 41 mN / m) were used, and adhesion and fuel barrier properties were evaluated. The results are shown in Table 1.

<Example 6>
As an epoxy resin, an epoxy resin having a glycidyl ether moiety derived from bisphenol A instead of an epoxy resin having a glycidylamine moiety derived from metaxylylenediamine (Mitsubishi Gas Chemical Co., Ltd .; TETRAD-X) manufactured by Japan epoxy Resins Co., Epikote 828) fuel barrier layer using the (fuel permeability coefficient ^{1.2 g · mm / m 2 ·} day, (1) to form a 37 wt% content of the skeletal structures of the formula). Other than that, members and tanks were produced in the same manner as in Example 1, and the adhesion and fuel barrier properties were evaluated. The results are shown in Table 1.

  The present invention can provide a method for producing a hollow molded body such as a fuel container having a high fuel barrier property at a low cost and in a simple manner.

Claims (12)

A method for producing a hollow molded body comprising a step of joining and integrating two or more members at a peripheral portion of the member, wherein at least one of the members is fueled on one or both sides of a thermoplastic polymer resin sheet. A method for producing a hollow molded article, comprising: forming a fuel barrier layer by applying a barrier coating, and then producing by pressure forming or vacuum forming. The method for producing a hollow molded article according to claim 1, wherein the fuel barrier layer has a fuel permeability coefficient at 60 ° C of 2 (g · mm / m ² · day) or less. 3. The method for producing a hollow molded article according to claim 1, wherein the fuel barrier layer contains 40% by weight or more of the skeleton structure of the formula (1).

The manufacturing method of the hollow molded object in any one of Claims 1-3 in which the said fuel-barrier coating material consists of an epoxy resin and an epoxy resin hardening | curing agent. The method for producing a hollow molded article according to claim 4, wherein the main component of the epoxy resin is an epoxy resin having a glycidylamine moiety derived from metaxylylenediamine. The method for producing a hollow molded article according to claim 4 or 5, wherein the epoxy resin curing agent is a reaction product of metaxylylenediamine and acrylic acid, methacrylic acid and / or a derivative thereof. The method for producing a hollow molded body according to any one of claims 1 to 6, wherein the thermoplastic polymer resin is polyethylene. The method for producing a hollow molded body according to any one of claims 1 to 7, wherein the coating method of the fuel barrier paint is at least one selected from dip coating, spray coating, brush coating, roll coating and flow coating. The method for producing a hollow molded body according to any one of claims 1 to 8, wherein the curing temperature of the fuel barrier coating material is 150 ° C or lower and the curing time is within 1 hour. The manufacturing method of the hollow molded object in any one of Claims 1-9 which surface-treat in advance to the surface of this thermoplastic polymer resin sheet which coats the said fuel-barrier coating material. The method for producing a hollow molded article according to claim 10, wherein the surface treatment method is at least one treatment method selected from corona treatment, flame treatment, plasma treatment, UV treatment, chemical treatment and primer treatment. The manufacturing method of the hollow molded object in any one of Claims 1-11 which formed the 1 or more types of protective layer in the surface of the said fuel barrier layer.