JP5117482B2 - Fuel tank - Google Patents

Description

  The present invention relates to a fuel tank using a polyphenylene sulfide resin composition.

  There are two types of resin fuel tanks for automobiles, one formed integrally by blow molding, and the other formed by welding two divided molded bodies formed by injection molding at a welding portion. In a fuel tank integrally formed by blow molding, a high-density polyethylene resin that is excellent in impact resistance and chemical resistance and low in cost has been conventionally used as a resin material for parison. However, the high density polyethylene resin has a problem of high fuel permeability. Therefore, a multilayer body having a barrier layer made of an ethylene-vinyl alcohol copolymer resin having a low fuel permeability and a barrier layer mainly composed of a copolymer polyamide resin of aromatic polyamide and nylon 6 and both surfaces of the barrier layer, respectively. There has been proposed a fuel tank comprising a multilayer hollow molded article having a laminated structure having an inner layer and an outer layer mainly composed of a high density polyethylene resin bonded via a joining layer mainly composed of modified high density polyethylene. (Patent Documents 1 and 2). However, the fuel tank by blow molding has the problem that productivity is inferior, and the pinch part that pinches the terminal by blow molding has a problem that the barrier layer is separated and becomes discontinuous, so that sufficient barrier property cannot be expressed. It was.

  On the other hand, in the case of welding two divided molded bodies formed by injection molding, the barrier layer can be directly welded, and the barrier layer discontinuous part of the pinch-off part as in blow molding does not occur, so the barrier property is excellent. However, there was a problem in achieving both good moldability and sufficient impact resistance.

  Here, polyphenylene sulfide resin has excellent properties such as excellent heat resistance, barrier properties, chemical resistance, electrical insulation properties, heat and humidity resistance, and various electrical / electronic components, mechanical components and automobiles, mainly for injection molding. It is used for parts and is also effective as a fuel tank material. However, since its flexibility and impact resistance are low, its application is currently limited, and improvements in flexibility and impact resistance are strongly desired. As a technique for imparting flexibility and impact resistance to a polyphenylene sulfide resin, a method of melt blending various soft resins has been studied. For example, a composition in which an epoxy group-containing olefin copolymer, an epoxy group, and an elastomer not containing an acid anhydride group are blended with a specific polyphenylene sulfide resin (Patent Document 3), an ethylene / α-olefin system having a specific molecular weight distribution A composition in which a copolymer and a functional group-containing olefin copolymer such as an epoxy group and an acid anhydride group are blended (Patent Document 4), a method of mixing an olefin copolymer in a specific dispersion state with a polyphenylene sulfide resin, Resin molded bodies using them, fuel system parts (Patent Documents 5 to 7), compositions combining specific polyphenylene sulfide resins with specific olefin copolymers and fuel tanks using the same (Patent Documents 8 and 9) Proposed.

  However, although Patent Documents 3 to 7 show an improvement in impact properties at room temperature conditions, impact properties at low temperatures (−40 ° C.) are not sufficient, while Patent Documents 8 and 9 improve impact properties at low temperatures. In a composition that exhibits sufficient low temperature impact resistance, the excellent rigidity inherent in polyphenylene sulfide resin tends to decrease, and there may be cases where sufficient performance cannot be expressed in a fuel tank sealability test or pressure resistance test. Therefore, there is a demand for a fuel tank having these characteristics in a highly balanced manner.

JP-A-6-340033 JP-A-6-191296 JP-A-1-306467 JP 2000-198923 A JP 2002-226604 A JP 2002-226706 A JP 2002-226707 A JP 2004-217888 A JP 2004-339478 A

  An object of the present invention is to obtain a fuel tank comprising a polyphenylene sulfide resin composition that solves the above-described problems and having low fuel swelling, pressure resistance, and low temperature impact resistance.

  The fuel tank of the present invention adopts the following configuration as a result of intensive studies to solve the above-described problems. That is, the present invention is as follows.

(1) A fuel tank obtained by melt-molding a polyphenylene sulfide resin composition, wherein the polyphenylene sulfide resin composition comprises (a) 78 to 88% by weight of a polyphenylene sulfide resin, and (b) an epoxy group-containing olefin copolymer. 1 to 21% by weight, and (c) 1 to 21% by weight of an ethylene / α-olefin copolymer obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms (however, the total of each component is 100 the percent by weight.) a, wherein (a) polyphenylene sulfide chloroform extraction amount of 0.01 to 1 wt% of the resin, and Ri der sodium content is 300ppm or more, and having a reinforcing strut structure Fuel tank.
(2) The (a) polyphenylene sulfide resin according to ASTM-D1238 has a melt flow rate of 50 to 200 g / 10 minutes measured at 315.5 ° C. and a load of 5000 g, as described in (1) above Fuel tank.
(3) The fuel tank according to (1) or (2), wherein (a) the polyphenylene sulfide resin is obtained by a quench method.
(4) The above (b), wherein the epoxy group-containing olefin copolymer is a copolymer of 90 to 99% by weight of ethylene and 1 to 10% by weight of an α, β-unsaturated carboxylic acid glycidyl ester. The fuel tank according to any one of 1) to (3).
(5) While the (a) polyphenylene sulfide resin forms a continuous phase, the shell phase of the (b) epoxy group-containing olefin polymer includes the core phase of the (c) ethylene / α-olefin copolymer. The fuel tank according to any one of (1) to (4), wherein the core-shell type dispersed phase is formed and the average dispersed particle diameter is 1 to 200 nm.
(6) The fuel tank according to any one of (1) to (5), wherein a part of or all of the reinforcing structure and component parts constituting the fuel tank are integrally formed.
(7) pre-Symbol fuel tank, the fuel tank according to any one of (1) to (6) characterized by having a maintenance hole.

  According to the present invention, by using a polyphenylene sulfide resin fat composition suitable for melt molding specifically excellent in low temperature impact resistance and rigidity, a fuel tank having low pressure resistance and low temperature impact resistance is obtained. Obtainable.

It is a model figure of a core-shell type dispersed phase structure. FIG. 3 is a model diagram of a core-shell type dispersed phase structure in which a core phase is partially included in a shell phase. 1 is a cross-sectional view of a fuel tank according to an embodiment of the present invention, where (a) is a cross-sectional view schematically showing the components of the fuel tank separated, and (b) is a little more schematically the structure where the fuel tank is welded. Sectional drawing which expands and is shown, (c) is an expanded sectional view of the welding part of a fuel tank. It is an expanded sectional view of the reinforcement support | pillar fastening part of the fuel tank of FIG. It is an expanded sectional view of the cap attachment part of the maintenance hole of the fuel tank of FIG. It is a model figure of the testing apparatus which evaluates the low temperature impact property of a fuel tank.

  Hereinafter, embodiments of the present invention will be described in detail.

  (A) Polyphenylene sulfide resin (hereinafter also referred to as “PPS resin”) contained in the polyphenylene sulfide resin composition (hereinafter also referred to as “PPS resin composition”) forming the fuel tank of the present invention. Is a polymer having a repeating unit represented by the following structural formula (I).

  From the viewpoint of heat resistance, the PPS resin is preferably a polymer containing 70 mol% or more, more preferably 90 mol% or more of the repeating unit represented by the above structural formula. In addition, the PPS resin may be composed of at least one repeating unit selected from repeating units having the following structure in an amount of less than 30 mol% of the repeating units.

  Since the PPS polymer having a part of the structure has a low melting point, it is advantageous in terms of moldability when the melting point is low in the resin composition forming the fuel tank of the present invention.

  PPS resin is excellent in heat resistance, chemical resistance, flame retardancy, electrical properties and mechanical properties, and is particularly suitably used for injection molding applications.

  The (a) PPS resin contained in the PPS resin composition used in the fuel tank of the present invention has a chloroform extraction amount of 0.01 to 1% by weight. (A) The amount of chloroform extracted from the PPS resin is more preferably 0.05 to 0.95% by weight, still more preferably 0.1 to 0.9% by weight. The amount of chloroform extracted in the present invention is an indicator of the amount of organic low polymerization component (oligomer). The amount of chloroform extracted in the present invention is calculated from the residual amount during 5 hours of Soxhlet extraction using 200 mL of chloroform for 10 g of PPS resin to be measured. When the amount of oligomer is in the above range as the chloroform extraction amount, the low-temperature impact property of the obtained PPS resin composition can be greatly improved. When the amount of chloroform extracted exceeds 1% by weight, the thread test performance of the resulting fuel tank tends to be lowered, which is not preferable.

  The (a) PPS resin contained in the PPS resin composition used in the fuel tank of the present invention has a sodium content of 300 ppm or more. The sodium content is more preferably 500 ppm or more, and particularly preferably 700 ppm or more. Although there is no restriction | limiting in particular about the upper limit of sodium content, It is preferable that it is 1500 ppm or less from the viewpoint of the thread test performance of the fuel tank obtained, and a moldability. The sodium content in the present invention is a value measured by atomic absorption analysis of a PPS resin placed on a platinum dish, subjected to ashing treatment and then treated with hydrochloric acid. When the sodium content is in the above range, the reaction between the resulting PPS resin and the epoxy group-containing olefin copolymer proceeds rapidly, so that the low temperature impact is greatly improved, and a fuel tank with good performance is obtained. Is possible.

  The (a) PPS resin contained in the PPS resin composition used in the fuel tank of the present invention has a melt flow rate (hereinafter abbreviated as MFR) measured at 315.5 ° C. and a load of 5000 g according to ASTM-D1238 at 50 to 50. It is preferable that it is 200 g / 10min. (A) The MFR of the PPS resin is more preferably 55 to 180 g / 10 minutes, and still more preferably 60 to 150 g / 10 minutes. When the MFR is less than 50 g / 10 minutes, the fluidity of the PPS resin composition is lowered, and the processability when molding the fuel tank is lowered, which is not preferable. Conversely, when the MFR exceeds 200 g / 10 min, the impact strength of the resulting PPS resin composition is lowered, and there is a possibility that cracking or the like may occur when an impact is applied to the fuel tank.

  The PPS resin is preferably a substantially linear PPS resin that is not subjected to high molecular weight by thermal oxidation crosslinking treatment. A PPS resin having an MFR within the above range without performing a high molecular weight by thermal oxidation crosslinking treatment is compared with a PPS resin obtained by converting a low molecular weight (high MFR) PPS resin to a high molecular weight by thermal oxidation crosslinking. High impact resistance. Furthermore, a substantially linear PPS resin is preferable because it easily forms a core-shell structure described later.

  The PPS resin can be produced in a high yield by recovering and post-treating the PPS resin obtained by reacting the polyhalogen aromatic compound and the sulfidizing agent in a polar organic solvent.

  A polyhalogenated aromatic compound refers to a compound having two or more halogen atoms in one molecule. Specific examples include p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, hexa Examples include chlorobenzene, 2,5-dichlorotoluene, 2,5-dichloro-p-xylene, 1,4-dibromobenzene, 1,4-diiodobenzene, 1-methoxy-2,5-dichlorobenzene and the like. Of these, p-dichlorobenzene is preferably used. Further, it is possible to combine two or more different polyhalogenated aromatic compounds into a copolymer, but it is preferable to use a p-dihalogenated aromatic compound as a main component.

  The amount of the polyhalogenated aromatic compound used is 0.9 to 2.0 mol, preferably 0.95 to 1.5 mol, per mol of the sulfidizing agent, from the viewpoint of obtaining a PPS resin having a viscosity suitable for processing. More preferably, the range of 1.005 to 1.2 mol can be exemplified.

  Examples of the sulfiding agent include alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide.

  Specific examples of the alkali metal sulfide include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and a mixture of two or more of these, and sodium sulfide is preferably used. These alkali metal sulfides can be used as hydrates or aqueous mixtures or in the form of anhydrides.

  Specific examples of the alkali metal hydrosulfide include, for example, sodium hydrosulfide, potassium hydrosulfide, lithium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide and a mixture of two or more of these. Preferably used. These alkali metal hydrosulfides can be used as hydrates or aqueous mixtures or in the form of anhydrides.

  In the present invention, the amount of the sulfidizing agent charged means the residual amount obtained by subtracting the loss from the actual charged amount when a partial loss of the sulfiding agent occurs before the start of the polymerization reaction due to dehydration operation or the like. Shall.

  An alkali metal hydroxide and / or an alkaline earth metal hydroxide can be used in combination with the sulfidizing agent. Specific examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide, and a mixture of two or more of these. Specific examples of the alkaline earth metal hydroxide include calcium hydroxide, strontium hydroxide, barium hydroxide and the like. Of these, sodium hydroxide is preferably used.

  When an alkali metal hydrosulfide is used as the sulfiding agent, it is particularly preferable to use an alkali metal hydroxide at the same time, but the amount used is 0.95 to 1. A range of 20 mol, preferably 1.00 to 1.15 mol, more preferably 1.005 to 1.100 mol can be exemplified.

  Hereinafter, an example of a method for producing (a) PPS resin contained in the PPS resin composition used in the fuel tank of the present invention will be described in order, including a pre-process, a polymerization reaction process, a recovery process, and a post-treatment process. I will explain it.

  First, the previous process will be described. The sulfidizing agent is usually used in the form of a hydrate, but before adding the polyhalogenated aromatic compound, the temperature of the mixture containing the organic polar solvent and the sulfidizing agent is increased, and excess water is removed from the system. It is preferable to remove it. In addition, when water is removed excessively by this operation, it is preferable to add and replenish the deficient water.

  As the sulfiding agent, an alkali metal sulfide prepared from an alkali metal hydrosulfide and an alkali metal hydroxide in situ in the reaction system or in a tank different from the polymerization tank can be used. Desirable conditions for preparing the alkali metal sulfide are from normal temperature to 150 ° C., more preferably from normal temperature to 100 ° C. in an inert gas atmosphere, and an alkali metal hydrosulfide and alkali metal hydroxide are added to the organic polar solvent. In addition, the temperature is raised to 150 ° C. or higher, more preferably 180 to 260 ° C. under normal pressure or reduced pressure to distill off the water. A polymerization aid may be added at this stage. Moreover, in order to accelerate | stimulate distillation of a water | moisture content, you may react by adding toluene etc.

  The amount of water in the polymerization system in the polymerization reaction is preferably 0.5 to 10.0 moles per mole of the charged sulfidizing agent. Here, the amount of water in the polymerization system is an amount obtained by subtracting the amount of water removed from the polymerization system from the amount of water charged in the polymerization system. In addition, the water to be charged may be in any form such as water, an aqueous solution, and crystal water. A more preferable range of the water content is 0.75 to 2.5 mol per mol of the sulfidizing agent, and a range of 1.0 to 1.25 mol is more preferable. In order to adjust the moisture to such a range, it is also possible to add moisture before or during the polymerization.

  In the polymerization reaction step, a PPS resin is produced by reacting a sulfidizing agent and a polyhalogenated aromatic compound in a temperature range of 200 ° C. or higher and 290 ° C. or lower in an organic polar solvent such as N-methyl-2-pyrrolidone. To do.

  When starting the polymerization reaction step, the sulfidizing agent and the polyhalogenated aromatic compound are added to the organic polar solvent in an inert gas atmosphere at a temperature ranging from room temperature to 220 ° C, preferably 100 to 220 ° C. At this stage, a polymerization aid such as sodium acetate may be added. Here, the polymerization assistant means a substance having an action of increasing the viscosity of the obtained PPS resin. The order in which these raw materials are charged may be out of order or may be simultaneous.

  The mixture is usually heated to a temperature in the range of 200 ° C to 290 ° C. Although there is no restriction | limiting in particular in a temperature increase rate, Usually, the speed of 0.01-5 degreeC / min is selected, and the range of 0.1-3 degreeC / min is more preferable.

  Finally, the temperature is raised to a temperature of 250 to 290 ° C., and the reaction is carried out at that temperature for 0.25 to 50 hours, preferably 0.5 to 20 hours.

  A method of raising the temperature to 250 to 290 ° C. after reacting at a temperature of, for example, 200 ° C. to 245 ° C. for a certain period of time before reaching the final temperature is effective in obtaining a higher degree of polymerization. At this time, the reaction time at 200 ° C. to 245 ° C. is usually selected within the range of 0.25 hours to 20 hours, preferably within the range of 0.25 to 10 hours.

  After completion of the polymerization, a solid is recovered from the polymerization reaction product containing a polymer, a solvent and the like.

(A) As a method for recovering the PPS resin contained in the PPS resin composition used in the fuel tank of the present invention in the recovery process, the polymerization reaction product is gradually cooled while crystallizing it, and then the solid is filtered and recovered. The method (quenching method) to do is mentioned preferably. By collecting by this quenching method, it is excluded from the particles in the crystallization process, so that impurities such as ionic compounds remaining in the collected solid and organic low polymerization products are easily removed. Therefore, it is suitable for obtaining a PPS resin having a chloroform extraction amount of 0.01 to 1% by weight used in the present invention. As another recovery method, the polymerization reaction product is flushed from a high-temperature and high-pressure state (usually 250 ° C. or higher, 8 kg / cm ² or higher) into an atmosphere of normal pressure or reduced pressure, and the polymer is recovered in powder form at the same time as the solvent recovery. Although there is a method (flash method), in this recovery method, the amount of chloroform extracted used in the present invention is 0.01 to 0.01 because impurities and organic low-polymerization products (oligomers) tend to be taken into the polymer during the solidification process. It is not preferable as a method for obtaining 1 wt% PPS resin.

  (A) The PPS resin contained in the PPS resin composition used in the fuel tank of the present invention is produced through the above polymerization and recovery steps, and then used after being subjected to hot water treatment or washing with an organic solvent (post treatment step). ). In addition, washing may be performed using an additive such as an alkaline earth metal salt or acid as appropriate during washing, but washing may be carried out without using the additive to obtain a PPS resin having the desired sodium content. preferable.

  When performing hot water treatment, it is as follows. In the hot water treatment of the PPS resin, the temperature of the hot water is preferably 100 ° C. or higher, more preferably 120 ° C. or higher, still more preferably 150 ° C. or higher, and particularly preferably 170 ° C. or higher. If it is less than 100 ° C., the effect of preferable chemical modification of the PPS resin is small, which is not preferable.

  The water used is preferably distilled water or deionized water in order to develop a preferable chemical modification effect of the PPS resin by hot water washing. The operation of the hot water treatment is usually performed by putting a predetermined amount of PPS resin into a predetermined amount of water, and heating and stirring in a pressure vessel. The ratio of the PPS resin to water is preferably washed using 1 kg or more of water per 1 kg of dry PPS resin, and more preferably 3 kg or more. Although there is no restriction | limiting in particular as an upper limit, It is preferable that it is 100 kg or less from the point of the usage-amount and the effect acquired.

  Moreover, since the decomposition of the end group of the PPS resin is not preferable, the atmosphere of the hot water treatment is desirably an inert atmosphere in order to avoid this. Further, the PPS resin after the hot water treatment operation is preferably washed several times with warm water in order to remove remaining components.

  When washing with an organic solvent, it is as follows. The organic solvent used for washing the PPS resin is not particularly limited as long as it does not have an action of decomposing the PPS resin. For example, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, 1,3-dimethylimidazolidinone, Nitrogen-containing polar solvents such as hexamethylphosphorus amide and piperazinones, sulfoxide / sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone and sulfolane, ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone and acetophenone, dimethyl ether, dipropyl ether, Ether solvents such as dioxane and tetrahydrofuran, chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchlorethylene, monochloroethane, dichloroethane, tetrachloroethane Halogen solvents such as perchlorethane, chlorobenzene, alcohol / phenol solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, polypropylene glycol, and benzene, toluene, Examples thereof include aromatic hydrocarbon solvents such as xylene. Among these organic solvents, use of N-methylpyrrolidone, acetone, dimethylformamide, chloroform and the like is preferable, and N-methyl-2-pyrrolidone is particularly preferable. These organic solvents are used alone or in combination of two or more.

  As an example of washing with an organic solvent, there is a method of immersing a PPS resin in an organic solvent, and stirring or heating can be appropriately performed as necessary, and washing may be performed a plurality of times. There is no restriction | limiting in particular about the washing | cleaning temperature at the time of wash | cleaning PPS resin with an organic solvent, Arbitrary temperature of about normal temperature-about 300 degreeC can be selected. Although the cleaning efficiency tends to increase as the cleaning temperature increases, a sufficient effect is usually obtained at a cleaning temperature of room temperature to 150 ° C. A particularly preferable washing temperature is 70 to 100 ° C. It is also possible to wash under pressure in a pressure vessel at a temperature above the boiling point of the organic solvent. There is no particular limitation on the cleaning time. Depending on the cleaning conditions, in the case of batch-type cleaning, a sufficient effect can be obtained usually by cleaning for 5 minutes or more. It is also possible to wash in a continuous manner. The ratio between the PPS resin and the organic solvent is preferably washed using 1 kg or more of organic solvent per 1 kg of dry PPS resin, and more preferably washed using 3 kg or more. Although there is no restriction | limiting in particular as an upper limit, It is preferable that it is 100 kg or less from the point of the usage-amount and the effect acquired. Moreover, after washing with an organic solvent, washing with warm water may be performed, and such warm water washing may be performed a plurality of times. The washing temperature with warm water is preferably from room temperature to 95 ° C, more preferably from 50 ° C to 90 ° C. Although the washing time with warm water depends on the washing conditions, in the case of batch washing, a sufficient effect can be obtained by washing usually for 5 minutes or more. It is also possible to wash in a continuous manner. The ratio of the PPS resin to warm water is preferably washed using 1 kg or more of warm water per 1 kg of dry PPS resin, and more preferably 3 kg or more. Although there is no restriction | limiting in particular as an upper limit, It is preferable that it is 100 kg or less from the point of the usage-amount and the effect acquired.

  These hot water treatment and washing with an organic solvent can be appropriately combined in order to obtain the desired melt viscosity, chloroform extraction amount, sodium content (a) PPS resin. In the present invention, the organic solvent PPS resin that has been washed by the above method is preferably used, and particularly preferably PPS resin that has been washed several times with an organic solvent and then washed with warm water three times or more.

  The (a) PPS resin contained in the PPS resin composition used in the fuel tank of the present invention preferably has an ash content of 0.1 wt% or more and 0.6 wt% or less, and 0.15 wt% or more. A range of 0.30% by weight or less is more preferable. When the amount of ash is in the above range, (a) the average dispersed particle size of the dispersed phase of the core-shell type structure dispersed in the PPS resin can be refined, and as a result, toughness (especially impact resistance at low temperatures and tensile properties) is improved. As a result, a fuel tank with excellent performance can be obtained. If the ash content is less than 0.15% by weight, the low-temperature tensile elongation is low, and the thread test performance of the resulting fuel tank is lowered, which is not preferable. On the other hand, in the range where the ash content exceeds 0.6% by weight, the formation of the core-shell structure described later is hindered. As a result, the low-temperature impact strength is lowered, and the thread test performance of the resulting fuel tank is lowered. Absent.

  Here, the amount of ash is measured by weighing about 5 g of PPS resin dried at 150 ° C. for 1 hour, putting it in a crucible, pre-combusting it for about 3 hours with an electric stove, and then using an electric furnace at 550 ° C., about 20 minutes. Burn for hours and completely ash. The residue weight was measured, and the ratio of the weight of the residue to the weight of the resin after drying was calculated.

  In the present invention, in order to control the ash contained in the PPS resin, the conditions for performing the hydrothermal treatment are one of the important requirements. Furthermore, the operation of washing the PPS resin after the hot water treatment operation with warm water is also an important requirement for controlling the ash content. If the amount of washing water is too small, the amount of ash increases, and if too much, the amount of ash tends to decrease.

  In addition, for the purpose of removing volatile matter, it is possible to perform a dry heat treatment at a low oxygen concentration while suppressing thermal oxidation crosslinking. The temperature is preferably 130 to 250 ° C, and more preferably 160 to 250 ° C. In this case, the oxygen concentration is preferably less than 5% by volume, and more preferably less than 2% by volume. The treatment time is preferably 0.5 to 50 hours, more preferably 1 to 20 hours, and still more preferably 1 to 10 hours.

  The (b) epoxy group-containing olefin copolymer contained in the PPS resin composition used in the fuel tank of the present invention is obtained by introducing an olefin polymer or a monomer component having an epoxy group into the olefin copolymer. It is an olefin copolymer.

  Examples of functional group-containing components for introducing a monomer component having an epoxy group include glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, glycidyl itaconate, etc. The body is mentioned.

  The method for introducing these epoxy group-containing components is not particularly limited, and methods such as copolymerization at the time of polymerization, or graft introduction to the olefin polymer or olefin copolymer using a radical initiator can be used.

  The amount of the monomer component containing an epoxy group is preferably 0.001 to 40 mol%, preferably 0.01 to 35 mol%, based on the entire epoxy group-containing olefin copolymer. .

  As the (b) epoxy group-containing olefin copolymer particularly useful in the present invention, an olefin copolymer containing an α-olefin and a glycidyl ester of an α, β-unsaturated carboxylic acid as an essential copolymerization component is preferably exemplified. As said alpha olefin, ethylene is mentioned preferably. These copolymers further include α, β-unsaturated carboxylic acids such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and the like. It is also possible to copolymerize the alkyl ester and the like.

  In the present invention, an olefin copolymer containing 80 to 99% by weight of an α-olefin and 1 to 20% by weight of a glycidyl ester of an α, β-unsaturated carboxylic acid as an essential copolymerization component is preferable, and an α-olefin of 90 to 99 is preferable. Olefin copolymers containing 1% by weight to 10% by weight of glycidyl ester of α, β-unsaturated carboxylic acid as essential copolymer components are particularly preferred.

（Ｒは水素原子または低級アルキル基を示す）で示される化合物であり、具体的にはアクリル酸グリシジル、メタクリル酸グリシジルおよびエタクリル酸グリシジルなどが挙げられるが、中でもメタクリル酸グリシジルが好ましく使用される。 The α, β-unsaturated carboxylic acid glycidyl ester is

(R represents a hydrogen atom or a lower alkyl group). Specific examples include glycidyl acrylate, glycidyl methacrylate, and glycidyl ethacrylate. Among them, glycidyl methacrylate is preferably used.

  As a specific example of an olefin copolymer having an α-olefin and a glycidyl ester of α, β-unsaturated carboxylic acid as an essential copolymerization component, an ethylene / propylene-g-glycidyl methacrylate copolymer (“g” is a graft) Represents the same), ethylene / butene-1-g-glycidyl methacrylate copolymer, ethylene / glycidyl acrylate copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / methyl acrylate / glycidyl methacrylate copolymer And polymers and ethylene / methyl methacrylate / glycidyl methacrylate copolymers. Among these, a copolymer selected from ethylene / glycidyl methacrylate copolymer, ethylene / methyl acrylate / glycidyl methacrylate copolymer and ethylene / methyl methacrylate / glycidyl methacrylate copolymer is preferably used.

  The (b) epoxy group-containing olefin copolymer contained in the PPS resin composition used in the fuel tank of the present invention has a melt flow rate (hereinafter abbreviated as MFR) measured at 190 ° C. under a load of 2160 g in accordance with ASTM-D1238. It is preferable that it is 0.01-70 g / 10min, More preferably, it is 0.03-60 g / 10min. An MFR of less than 0.01 g / 10 min is not preferable because the moldability of the fuel tank is reduced. When this MFR exceeds 70 g / 10 minutes, the impact strength is lowered depending on the shape of the fuel tank, so that the thread test performance of the obtained fuel tank is lowered, which is not preferable.

The density of the (b) epoxy group-containing olefin copolymer contained in the PPS resin composition used in the fuel tank of the present invention is preferably 850 to 990 kg / m ³ . When the density exceeds 990 kg / m ³ , the toughness tends to decrease, which is not preferable. If the density is less than 850 kg / m ³ , the handling property is lowered, which is not preferable.

  The ethylene / α-olefin copolymer obtained by copolymerizing (c) ethylene and an α-olefin having 3 to 20 carbon atoms contained in the PPS resin composition used in the fuel tank of the present invention is ethylene. And a copolymer comprising at least one α-olefin having 3 to 20 carbon atoms as a constituent component. Specific examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene and 1-undecene. 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1 -Pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl -1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene and these See fit, and the like. Among these α-olefins, a copolymer using an α-olefin having 4 to 12 carbon atoms is more preferable because mechanical strength is improved and a reforming effect is further improved. The (c) ethylene / α-olefin copolymer is an olefin copolymer containing no epoxy group.

  The ethylene / α-olefin copolymer obtained by copolymerizing (c) ethylene and an α-olefin having 3 to 20 carbon atoms contained in the PPS resin composition used in the fuel tank of the present invention is ASTM-D1238. Accordingly, the melt flow rate (hereinafter abbreviated as MFR) measured at 190 ° C. under a load of 2160 g is preferably 0.01 to 50 g / 10 minutes, more preferably 0.03 to 40 g / 10 minutes. An MFR of less than 0.01 g / 10 min is not preferable because the moldability of the fuel tank is reduced. When the MFR exceeds 50 g / 10 minutes, depending on the shape of the fuel tank, the impact strength is lowered, and therefore the thread test performance of the obtained fuel tank is lowered, which is not preferable.

The density of the ethylene / α-olefin copolymer obtained by copolymerizing (c) ethylene and an α-olefin having 3 to 20 carbon atoms contained in the PPS resin composition used in the fuel tank of the present invention is 800 to 920 kg / m ³ is preferred. When the density exceeds 920 kg / m ³ , low temperature impact resistance is hardly exhibited, and fuel tank performance at low temperatures is lowered, which is not preferable. If the density is less than 800 kg / m ³ , handling properties are lowered, which is not preferable.

  The blending ratio of (a) PPS resin, (b) epoxy group-containing olefin copolymer, and (c) ethylene and an α-olefin having 3 to 20 carbon atoms in the PPS resin composition used in the fuel tank of the present invention is ( a) PPS resin 78 to 88% by weight, (b) epoxy group-containing olefin copolymer 1 to 21% by weight, and (c) ethylene obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms / Α-olefin copolymer 1 to 21% by weight (however, the total of each component is 100% by weight), preferably (a) 80 to 86% by weight of PPS resin, and (b) epoxy group-containing olefin copolymer. 1 to 19% by weight of a polymer, and (c) 1 to 19% by weight of an ethylene / α-olefin copolymer obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms (however, the total of each component) The 100 wt%). If the PPS resin is less than 78% by weight, the heat stability and barrier properties inherent to the PPS resin are impaired, which is not preferable. On the other hand, if the PPS resin is more than 95% by weight, the excellent thread test performance, which is a feature of the present invention, cannot be exhibited, which is not preferable. Furthermore, the blending ratio of the ethylene / α-olefin copolymer obtained by copolymerizing (b) the epoxy group-containing olefin copolymer of the present invention, (c) ethylene and an α-olefin having 3 to 20 carbon atoms is as follows: The component (b) is preferably 5 to 60% by weight and the component (c) is preferably 95 to 40% by weight, more preferably the component (b) is 10 to 50% by weight and the component (c) 90 to 50% by weight, more preferably 10 to 40% by weight of component (b) and 90 to 60% by weight of component (c). In the fuel tank obtained when the component (b) is less than 5% by weight, the desired morphology tends to be difficult to obtain. On the other hand, when the amount of the component (b) is more than 60% by weight, the thickening at the time of melt-kneading increases, and the molding processability of the fuel tank tends to decrease.

  Furthermore, in the present invention, in order to impart high heat resistance and thermal stability to the PPS resin composition used in the fuel tank, one or more selected from phenolic antioxidants and phosphorus antioxidants It is preferable to contain an antioxidant. From the standpoint of the heat resistance improving effect, the antioxidant is blended with (a) a PPS resin, (b) an epoxy group-containing olefin copolymer, and (c) ethylene and an α-olefin having 3 to 20 carbon atoms. It is preferable that it is 0.01 weight part or more with respect to a total of 100 weight part of the ethylene / alpha-olefin copolymer obtained by superposition | polymerization, especially 0.02 weight part or more. The blending amount of the antioxidant is, from the viewpoint of the gas component generated at the time of molding, (a) PPS resin, (b) epoxy group-containing olefin copolymer, and (c) ethylene and an α-olefin having 3 to 20 carbon atoms. Is preferably 5 parts by weight or less, particularly preferably 1 part by weight or less, based on a total of 100 parts by weight of the ethylene / α-olefin copolymer obtained by copolymerization of In addition, it is particularly preferable to use a phenolic antioxidant and a phosphorus antioxidant in combination since the heat resistance and thermal stability retention effects are particularly large.

  As the phenolic antioxidant, a hindered phenolic compound is preferably used. Specific examples include triethylene glycol-bis [3-t-butyl- (5-methyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-t-butyl-4 -Hydroxy-hydrocinnamide), tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, pentaerythrityltetrakis [3- (3 ′, 5′-di) -T-butyl-4'-hydroxyphenyl) propionate], 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -s-triazine-2,4,6- (1H , 3H, 5H) -trione, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 4,4′-butylidenebis (3-methyl) -6-tert-butylphenol), n-octadecyl-3- (3,5-di-tert-butyl-4-hydroxy-phenyl) propionate, 3,9-bis [2- (3- (3-tert-butyl) -4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, 1,3,5-trimethyl-2, Examples include 4,6-tris- (3,5-di-t-butyl-4-hydroxybenzyl) benzene. Among them, ester type polymer hindered phenol type is preferable. Specifically, tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, pentaerythrityl. Tetrakis [3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate], 3,9-bis [2- (3- (3-t-butyl-4-hydroxy-5- Methylphenyl) propionyloxy) -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane and the like are preferably used.

  Phosphorus antioxidants include bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol-di -Phosphite, bis (2,4-di-cumylphenyl) pentaerythritol-di-phosphite, tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) ) -4,4′-bisphenylene phosphite, di-stearyl pentaerythritol-di-phosphite, triphenyl phosphite, 3,5-dibutyl-4-hydroxybenzyl phosphonate diethyl ester and the like.

  Among them, in order to reduce the volatilization and decomposition of the antioxidant during molding of the fuel tank, those having a high melting point of the antioxidant are preferable. Specifically, bis (2,6-di-t-butyl-4-methyl) is preferable. Phenyl) pentaerythritol-di-phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol-di-phosphite, bis (2,4-di-cumylphenyl) pentaerythritol-di-phosphite, etc. Preferably used.

  Further, the PPS resin composition used in the fuel tank of the present invention has (b) an epoxy group-containing olefin copolymer and (c) ethylene and an α-carbon atom having 3 to 20 carbon atoms within the range not impairing the effects of the present invention. It is possible to add a thermoplastic resin other than the ethylene / α-olefin copolymer obtained by copolymerizing with olefin. For example, the flexibility and impact resistance can be further improved by adding a small amount of a highly flexible thermoplastic resin. However, if this amount exceeds 50% by weight of the whole composition, the original characteristics of the PPS resin are impaired, and it is particularly preferable to add 30% by weight or less. Specific examples of the thermoplastic resin include polyamide resin, polybutylene terephthalate resin, polyethylene terephthalate resin, modified polyphenylene ether resin, polysulfone resin, polyallyl sulfone resin, polyketone resin, polyetherimide resin, polyarylate resin, liquid crystal polymer, Examples include polyether sulfone resin, polyether ketone resin, polythioether ketone resin, polyether ether ketone resin, polyimide resin, polyamideimide resin, and tetrafluoropolyethylene resin.

  Moreover, the following compounds can be added for the purpose of modification. Coupling agents such as isocyanate compounds, organosilane compounds, organotitanate compounds, organoborane compounds, epoxy compounds, polyalkylene oxide oligomer compounds, thioether compounds, ester compounds, organophosphorus compounds, etc. , Talc, kaolin, organophosphorus compounds, crystal nucleating agents such as polyether ether ketone, montanic acid waxes, metal soaps such as lithium stearate and aluminum stearate, ethylenediamine / stearic acid / sebacic acid polycondensates, silicone compounds Other additives such as release agents such as hypophosphorous acid, anti-coloring agents such as hypophosphite, and other additives such as lubricants, ultraviolet light inhibitors, coloring agents, flame retardants, and foaming agents can be blended. If any of the above compounds exceeds 20% by weight of the total composition, the original properties of the PPS resin are impaired, which is not preferred, preferably 10% by weight or less, and more preferably 1% by weight or less.

  In the present invention, it is preferable to add a coupling agent such as an organic silane in order to further improve the low temperature toughness and improve the fuel tank performance. The compounding quantity of organosilane is 0.1-3 weight part with respect to 100 weight part of (a) PPS resin, Preferably it is 0.5-2.5 weight part.

  Moreover, it is also possible to mix | blend and use the filler for the PPS resin composition used for the fuel tank of this invention in the range which does not impair the effect of this invention. Specific examples of such fillers include glass fiber, carbon fiber, potassium titanate whisker, zinc oxide whisker, calcium carbonate whisker, wollastonite whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber. , Fibrous fillers such as gypsum fiber and metal fiber, or silicates such as talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, bentonite, asbestos, alumina silicate, silicon oxide, magnesium oxide , Metal compounds such as alumina, zirconium oxide, titanium oxide and iron oxide, carbonates such as calcium carbonate, magnesium carbonate and dolomite, sulfates such as calcium sulfate and barium sulfate, calcium hydroxide, magnesium hydroxide and hydroxide Hydroxides such as aluminum, glass beads, glass flakes, glass powder, ceramic beads, boron nitride, silicon carbide, carbon black and silica, and a non-fibrous fillers such as graphite. These may be hollow, and two or more of these fillers may be used in combination. These fillers may be used after pretreatment with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, and an epoxy compound.

  The PPS resin composition used in the fuel tank of the present invention can be prepared by melt-kneading using a kneader. As the kneader used for the production of the PPS resin composition, a generally known melt kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, or a mixing roll can be used. Among these, an extruder, particularly a twin screw extruder is preferable in terms of productivity. A typical example of the method for producing the PPS resin composition is a method in which each compounding component is supplied to a kneader selected from these components and kneaded at a processing temperature equal to or higher than the melting point of the PPS resin. In addition, for the purpose of removing moisture generated during melt-kneading and low molecular weight volatile components, it is also preferable to provide a vent port in the kneader.

  In order to control the dispersion form (morphology) of the PPS resin composition of the present invention so as to have a core-shell structure described later using a twin-screw extruder, kneading energy during extrusion (extruder work amount per discharge amount) It is necessary to increase (kW / (kg / h))). Although it may vary depending on the size of the extruder, for example, a preferable kneading energy when kneading using a twin screw extruder having a cylinder diameter of 30 mm is 0.4 (kW / (kg / h)) or more, and is particularly preferable. Is 0.45 (kW / (kg / h)) or more. As a result, good melt-kneading can be performed, and the intended resin phase separation structure can be formed. When the kneading energy is too large, it is preferably 0.65 (kW / (kg / h)) or less because thermal decomposition due to heat generation occurs as described later. In general, when the kneading energy is increased, the resin temperature rises due to heat generated by shearing, causing thermal decomposition of the molten resin and causing deterioration of physical properties. The resin temperature here refers to a temperature obtained by measuring, for example, a molten resin discharged from an extruder die with a thermometer. Therefore, the resin temperature when melt-kneading the PPS resin composition of the present invention is preferably in the range of 320 ° C to 350 ° C. Controlling the kneading energy and the resin temperature during the melt-kneading in this way is preferable because it makes it possible to form the desired dispersion structure while suppressing decomposition.

  An example of a method for controlling the kneading conditions as described above will be described. In melt-kneading using a twin-screw extruder, a method in which the cylinder temperature is set to a low temperature and the screw rotation speed is set to a high rotation speed is preferable because high shear can be obtained and high kneading energy can be achieved. However, in this case, when a conventional kneading disk is used as the screw element of the kneading section, the amount of heat generated by shearing is large, and it is difficult to control the resin temperature during extrusion as described above. On the other hand, it is preferable to use a low exothermic kneading element for the screw element of the kneading part because heat generation due to shearing can be suppressed and the resin temperature control during extrusion becomes easy. The low heat generation element referred to here is a screw element in which the flight tip portions arranged in parallel in the conventional kneading disk are inclined within a range of the spiral angle of 0 to 90 degrees or 90 to 180 degrees, and a notch shape. Examples include screw elements that use stirring elements instead of conventional shearing to knead mainly by stirring, and by introducing these into the kneading part of the screw, the effect of suppressing the temperature rise of the resin that is lacking in conventional kneading disks can be achieved. Obtainable. A method of introducing supercritical carbon dioxide or supercritical nitrogen into the kneading part is also preferable because heat generation due to shearing can be suppressed.

  When the cylinder temperature of the twin-screw extruder is divided into a plasticizing part for plasticizing the resin charged into the twin-screw extruder and a kneading part for melting and kneading the plasticized molten resin, the plasticizing part (a) The temperature is preferably from the melting point of the PPS resin to the melting point + 20 ° C., and the cylinder temperature of the kneading part is preferably in the range of 150 to 300 ° C. At this time, the mixing order of the raw materials is not particularly limited. A method in which all raw materials are supplied to a kneader in a batch and melt-kneaded, a part of raw materials are supplied and melt-kneaded, and then the remaining raw materials are supplied and melted. Any method may be used, such as a kneading method, or a method in which a part of the raw material is supplied and then the remaining raw material is supplied and melt-kneaded using a side feeder while being melt-kneaded by a single-screw or twin-screw extruder. . Among them, (a) the PPS resin is supplied from the supply port at the upstream portion of the extruder, (b) the epoxy group-containing olefin copolymer, (c) the ethylene / α-olefin copolymer and other components are supplied to the downstream portion of the extruder. A side feed method is preferred. Moreover, about a small amount additive component, after kneading | mixing and pelletizing another component by said method etc., it is also possible to add before shaping | molding and to use for shaping | molding.

  In the fuel tank of the present invention, (a) the PPS resin forms a continuous phase (matrix), (b) an epoxy group-containing olefin copolymer and (c) ethylene and an α-olefin having 3 to 20 carbon atoms. The ethylene / α-olefin copolymer obtained by polymerization preferably has a dispersed form (morphology) that forms a dispersed phase. Thereby, a fuel tank having low fuel swelling property, excellent pressure resistance, and thread test performance can be obtained.

  In the fuel tank of the present invention, as shown in FIG. 1, the PPS resin 1 forms a continuous phase (matrix), and (b) the epoxy group-containing olefin copolymer component 2 forms a primary dispersed phase (shell phase). Further, it is preferable to form a core-shell type dispersed phase in which the secondary dispersed phase (core phase) of (c) ethylene / α-olefin copolymer component 3 is included in the primary dispersed phase (shell phase). It has been found that by forming such a core-shell structure, impact resistance (that is, low temperature toughness) particularly in a low temperature region is remarkably improved. Here, as the core-shell structure, the shell phase preferably includes the entire core phase as shown in FIG. 1, but the shell phase partially includes the core phase as shown in FIG. It may be in a state. In this case, it is preferable that (b) component 2 covers 50% or more, preferably 80% or more of the outer periphery of the dispersed phase.

  Here, whether or not the core-shell structure is formed can be confirmed by observing a part of a cross-section of the fuel tank with an electron microscope. After ruthenium-staining a partial fragment of the fuel tank, a thin piece of 0.1 μm or less is cut, and observed and judged at a magnification of 10,000 using a transmission electron microscope.

  In the present invention, that the dispersed phase forms a core-shell structure means that the ratio of the number of dispersed phases having a core-shell structure is 50% or more, more preferably 80% or more with respect to the total number of dispersed phases thus observed. Say that. When the proportion of the dispersed phase having the core-shell structure is less than 50%, it is assumed that the core-shell structure is not provided.

  Moreover, it is preferable that the average particle diameter in (a) PPS resin of a core-shell type dispersion phase is disperse | distributing at 1-200 nm, and it is more preferable to disperse | distribute at 20-150 nm. This dispersion can be observed with a transmission electron microscope after cutting a thin piece of 0.1 μm or less from the PPS resin composition without staining and using a freezing method. For 100 randomly selected core-shell type dispersed phases, first, the maximum and minimum diameters of the respective core layer outer diameters were measured to obtain an average value, and the particle diameter of each dispersed phase was obtained. The particle diameter of the dispersed phase is averaged to obtain the average particle diameter.

  An example of an embodiment of the fuel tank of the present invention is shown in FIGS. 3 (a) to 3 (c), FIG. 4 and FIG.

  3A and 3B, the fuel tank includes an upper shell 4 and a lower shell 5. The upper shell 4 and the lower shell 5 are injection-molded with a PPS resin composition and joined by a welded portion 6. As shown in FIG. 3 (c), the welded portion 6 includes a lower end surface 41 of the upper shell 4 (with a flange 42 whose outer periphery protrudes outward in the illustrated example) and an upper end surface 51 of the lower shell 5 (also flange 52. Are attached to each other and welded together.

The fuel tank has a reinforcing support structure as a structural member inside . As the reinforcing support structure, for example, a reinforcing support 7 formed in a columnar shape can be arranged. The reinforcing column 7 can be molded using polyacetal resin (POM) or the like. The reinforcing strut 7 has fitting portions having annular protrusions outward at both ends thereof, and is formed on the strut fastening portion 43 formed on the upper surface inner surface side of the upper shell 4 and the lower surface inner surface side of the lower shell 5. It is fixed in the fuel tank by being fitted to the column fastening portions 53 respectively.

  As shown in FIG. 5, a maintenance hole 8 can be formed on the upper surface (general part) of the upper shell 4, and the maintenance hole cap 10 can be repeatedly attached and detached, for example, so as to fit into the mounting flange 44 of the maintenance hole 8. It can be attached via the O-ring 9 by a nayobayone method. The maintenance hole cap 10 can be molded using polyacetal resin (POM) or the like.

  The fuel tank of the present invention can be manufactured by the following method. The PPS resin composition used in the fuel tank of the present invention is injected into a mold for upper shell, and an inverted bottomed cup-shaped upper shell 4 having an open bottom surface is injection-molded, and similarly injected into a mold for lower shell. The bottomed cup-shaped lower shell 5 having an open upper surface is injection molded. In this injection molding process, the upper shell 4 and the lower shell 5 which are divided and molded separately are integrally formed by welding the joining peripheral edge portion (welding part 6) in each opening in the joining process. For this reason, the fuel tank formed by combining the upper shell and the lower shell can provide a precise and high strength product with high dimensional accuracy.

  Any injection molding can be used as long as it is a known injection molding machine used in the injection molding process for molding the divided molded body constituting the fuel tank of the present invention, and is not particularly limited. In the case of the PPS resin, the mold temperature in the injection molding process is generally set to 130 ° C. or more in order to sufficiently bring out the characteristics of the material. However, the present invention is not particularly limited.

  As a welding method used in the joining step for joining the divided molded bodies obtained in the injection molding process, preferably, hot plate welding, injection welding, vibration welding, heat ray welding and laser welding can be exemplified, and the joining surface of the divided molded body The step of welding the two can be performed, for example, as follows.

  In the case of the hot plate welding method, the joining surfaces of the divided molded bodies are melted by a hot plate, and the bonded surfaces of the divided molded bodies are quickly pressed and welded together. As the hot plate conditions at this time, normal conditions may be taken. For example, in the case of a contact method, for example, a hot plate temperature of 290 to 350 ° C., a melting time of 10 to 120 seconds, and an indentation allowance of 0.1 to 2 mm are adopted. Can do.

  In the case of the injection welding method, after the divided molded body is inserted into the mold or the position is changed in the mold, the bonded surfaces are held together, and a molten resin is newly injected to the periphery of the bonded portion. The divided molded bodies are welded together to form a container. The injection welding conditions at this time may be normal conditions. For example, a resin temperature of 300 to 320 ° C., an injection pressure of 10 to 150 MPa, a mold clamping force of 100 to 4000 tons, and a mold temperature of 30 to 80 ° C. may be adopted. (Note that the method of changing the position in the mold described above is also called die slide molding or die rotation molding).

  In the case of the vibration welding method, the joint surfaces of the divided molded bodies are brought into a state where they are pressed up and down, and in this state, welding is performed by frictional heat generated by applying vibration in the lateral direction. The vibration conditions at this time may be normal conditions. For example, a vibration frequency of 100 to 300 Hz and an amplitude of 0.5 to 2.0 mm can be employed.

  In the case of the hot wire welding method, for example, the joining surfaces are pressed together in a state where an iron-chromium wire is embedded in the joint portion of the divided molded body, current is applied to the wire material to generate Joule heat, and the joining surface is welded by the heat generation. .

  In the case of the laser welding method, the laser beam is irradiated from the non-absorbing split molded body side in a state where the split molded body non-absorbing with respect to the laser beam and the split molded body absorbing with respect to the laser beam are overlapped on the bonding surface. (For example, in the fuel tank, the upper shell 4 is made laser non-absorbing and the lower shell 5 is made laser absorbing, and laser light is irradiated from the upper shell 4 side). Moreover, in order to make it a laser beam absorptivity, the method of adding carbon black can be illustrated. By adding carbon black, the transmittance of the irradiated laser beam can be reduced to 5% or less, and the energy of the laser beam can be efficiently converted into heat. The laser welding conditions at this time may be normal conditions. For example, a YAG laser, a laser beam wavelength of 800 to 1060 nm, and a laser beam output of 5 to 30 W can be adopted as the laser beam.

  Among the welding methods used in these joining steps, hot plate welding is particularly preferable from the viewpoint of the strength of the welded portion and molding processability.

  The fuel tank of the present invention can be molded integrally with a part or all of the components constituting the reinforcing structure and the fuel tank at the time of molding. A part attaching portion and a reinforcing rib can be formed inside the upper shell and the lower shell, and built-in parts and the like can be easily attached and the strength of the fuel tank can be easily improved.

  When part or all of the parts constituting the reinforcing structure and the fuel tank are integrally molded during molding, a change in thickness or a notch shape can be achieved. In fuel tanks molded with conventional PPS resin compositions (Patent Documents 3 to 7) that do not have sufficient impact properties at low temperatures (−40 ° C.), they may be broken starting from their shapes, and are integrally molded. It was difficult. On the other hand, since the fuel tank made of the PPS resin composition of the present invention has excellent low temperature impact resistance, these components can be integrally molded.

  In addition, when improving impact properties at low temperatures, conventionally, in a composition that exhibits sufficient low temperature impact properties, a large amount of elastomer and soft resin are blended, so the excellent rigidity inherent in PPS resins Since there is a tendency to decrease, and strength reduction and dimensional change due to fuel swelling are large, sufficient performance may not be manifested in the amount of swelling deformation and pressure resistance test of the fuel tank. It was difficult. On the other hand, since the fuel tank made of the PPS resin composition of the present invention has rigidity and low fuel swelling property, these components can be integrally formed.

  The fuel tank of the present invention can be integrally formed with a reinforcing support structure. When the upper shell 4 and the lower shell 5 are injection-molded, the column fastening portions 43 and 53 into which the reinforcing columns 7 (for example, polyacetal resin; manufactured by POM) are fitted are integrally formed. When the lower end surface of the upper shell 4 and the upper end surface of the lower shell 5 are welded, the reinforcing column 7 is fitted into the column fastening portions 43 and 53. The reinforcing column 7 is attached to suppress deformation of the fuel tank against positive pressure and negative pressure.

  In a conventional fuel tank molded with a PPS resin composition that does not have sufficient low-temperature (−40 ° C.) impact properties, when the low-temperature impact test is performed, the protrusions of the column fastening portions 43 and 53 may start and break. However, the fuel tank of the present invention is excellent in low temperature impact resistance and therefore does not break.

  In addition, when a pressure resistance test in which a positive pressure of 200 kPa is applied to the tank after the fuel tank is filled with the fuel and swollen, the rigidity tends to decrease in the conventional composition that exhibits sufficient low-temperature impact properties. And since the strength reduction by fuel swelling is large, if the up-and-down tensile force acts on the support | pillar fastening part, the destruction 54 will arise in a fastening part and a tank will deform | transform. On the other hand, the fuel tank of the present invention has rigidity and low fuel swellability, so that there is little decrease in strength after the fuel swells, and the shape can be maintained without breaking the fastening portion.

  The fuel tank of the present invention can be provided with a maintenance hole 8. A maintenance hole cap 10 (for example, made of POM) is attached to the maintenance hole 8 via an O-ring 9 (for example, made of fluoro rubber) by, for example, a bayonet method that can be repeatedly attached and detached. The maintenance hole 8 is for maintenance personnel to put their hands into the tank when repairing or servicing the fuel tank. It can also be used as a mounting flange for a pump module that pumps fuel from the tank.

  In a conventional fuel tank molded from a PPS resin composition that does not have sufficient low-temperature (−40 ° C.) impact properties, when the low-temperature impact test is performed, the flange shape of the maintenance hole 8 may be the starting point and may be destroyed. The fuel tank of the invention is excellent in low temperature impact resistance and therefore does not break.

  In addition, in the conventional composition that exhibits sufficient low-temperature impact properties, when a sealing property test is performed in which a positive pressure of 50 kPa is applied to the tank after the fuel is sealed in the fuel tank and swelled, the dimensional change due to fuel swelling is large. For this reason, airtight leakage occurs, resulting in poor sealing. On the other hand, since the fuel tank of the present invention has rigidity and low fuel swellability, the dimensional change after fuel swell is small, and the hole inner diameter dimension hardly changes and the sealing performance can be maintained.

  The fuel tank of the present invention can be used as a fuel tank for a two-wheeled vehicle, a three-wheeled vehicle, a four-wheeled vehicle, a vehicle having six or more wheels, and the like. In addition to automobiles (including motorcycles), leisure equipment such as ships, airplanes, snowmobiles, water bikes, industrial equipment such as heavy construction machines (such as bulldozers) and generators, and agricultural equipment such as mowers and tractors. It is also useful as a fuel tank.

  The present invention will be described more specifically with reference to the following examples.

  In the following examples, the material properties were measured by the following method.

(1) Chloroform extraction amount About 10 g of PPS resin was weighed and put into a cylindrical filter paper, and Soxhlet extraction was performed using 200 mL of chloroform at a bath temperature of 120 ° C. for 5 hours. After extraction, chloroform was distilled off, and the residual amount was weighed and calculated per polymer weight.

(2) Sodium content 5 g of PPS resin was placed on a platinum dish, ashed at 538 ° C., and treated with hydrochloric acid, and measured by atomic absorption spectrometry using an atomic absorptivity meter AA-670 manufactured by Shimadzu Corporation.

(3) Morphological observation (core-shell structure)
An ASTM No. 1 dumbbell test piece was molded by injection molding using the PPS resin composition. (A) an epoxy group-containing olefin copolymer in a PPS resin matrix, and (c) an ethylene / α-olefin copolymer obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms. Whether the core-shell structure is formed or not is determined by cutting the central part of the test piece in a direction perpendicular to the flow direction, dyeing the central part of the cross section, and 0.1 μm or less at room temperature. The thin piece was cut and observed with a transmission electron microscope at a magnification of 10,000 times. In a state where 20 or more dispersed phases are observed in the same field of view, it is determined whether or not a core-shell structure is formed for each dispersed phase, and the ratio of the dispersed phases having the core-shell structure to the total number of dispersed phases is determined. Judgment was made as follows. ◎ is good, ○ is slightly good, and x is insufficient.
◎: Formation of core-shell structure is 80% or more ○: Formation of core-shell structure is 50% or more and less than 80% ×: Formation of core-shell structure is less than 50%

(4) Morphological observation (dispersed particle size)
An ASTM No. 1 dumbbell test piece was molded by injection molding using the PPS resin composition. The central part of the test piece was cut in a direction perpendicular to the flow direction, and a thin piece of 0.1 μm or less was cut from the central part of the cross section by a freezing method and observed with a transmission electron microscope at a magnification of 10,000 times. . For 100 randomly selected core-shell dispersed phases, first, the maximum and minimum diameters of the core layer outer diameters were measured to determine the average value, and the particle diameter of each dispersed phase was obtained. The average particle diameter was averaged.

(5) MFR
The MFR of the PPS resin composition was measured according to ASTM-D1238 at a measurement temperature of 315.5 ° C. and a load of 5000 g.

(6) High-speed tensile elongation (-40 ° C)
An ASTM No. 1 dumbbell test piece was molded by injection molding using the PPS resin composition. Using the obtained ASTM No. 1 dumbbell test piece, elongation at break was measured under the condition of a tensile speed of 500 mm / min according to ASTM D638 except that the temperature atmosphere was set to −40 ° C. Measurement was performed on three test pieces, and an average value was obtained.

(7) Izod impact strength (23 ° C)
Using the PPS resin composition, a notched specimen having a thickness of 1/8 inch as defined in ASTM-D256 was prepared by injection molding. The notched Izod impact strength was measured at 23 ° C. according to ASTM-D256. Measurement was performed on five test pieces, and an average value was obtained.

(8) Izod impact strength (-40 ° C)
The notched Izod impact strength was measured according to ASTM D256 in the same manner as the above Izod impact strength except that the measurement temperature was −40 ° C.

(9) Bending elastic modulus Using the PPS resin composition, a 1/4 inch thick bending test piece defined in ASTM-D790 was prepared by injection molding. According to ASTM-D790, a bending test was performed at 23 ° C. to measure the elastic modulus. Measurement was performed on three test pieces, and an average value was obtained.

(10) Swelling deformation amount The initial inner diameter (inner diameter dimension 45 of the upper shell 4 in FIG. 5) of the maintenance hole of the fuel tank manufactured by the manufacturing method described later using the PPS resin composition was measured with calipers. Next, about 75% of the test fuel (toluene) was sealed in the welded tank container with respect to the tank capacity, and soaked at 65 ° C. for 2000 hours. The inner diameter of the maintenance hole after the soak (inner diameter dimension 45 in FIG. 5) was measured with calipers, the difference between the inner diameter after fuel soaking and the initial inner diameter was measured, and the resulting change in inner diameter dimension was defined as the amount of swelling deformation.

(11) Tank deformation amount A tank in which about 75% of the test fuel (toluene) is sealed in a fuel tank container using the PPS resin composition and manufactured by the manufacturing method described later, and soaked at 65 ° C. for 2000 hours. The interior was filled with compressed air and a positive pressure of 20 kPa was added to confirm the amount of tank deformation. Regarding the amount of tank deformation, the height of the tank before and after the positive pressure load was measured with a height gauge, and the amount of change was obtained.

(12) Sealability test Following the measurement of the amount of tank deformation in (11) above, a positive pressure of 50 kPa was applied to the tank, the tank body was submerged, and the presence or absence of airtight leakage in the O-ring seal portion was confirmed. ○ indicates no airtightness, and × indicates airtightness.

(13) Pressure resistance test (strut fastening part destruction)
Following the sealing property test of (12) above, a positive pressure of 200 kPa was further applied to the tank for 3 seconds to confirm whether or not the strut fastening portion was broken. For the column fastening portion destruction, after the pressure resistance test, the cap of the maintenance hole was removed, and the presence or absence of the column fastening portion destruction inside the tank (in FIG. 4, the presence or absence of the breaking portion 54 at the column fastening portion 53 of the lower shell 5) was confirmed. . A positive pressure was applied, and the case where the strut fastening part did not break was judged as ◯, and the broken part as x.

(14) Low temperature impact test (thread test)
About 75% of the antifreeze (ethylene glycol) is sealed in the tank of the fuel tank manufactured by the manufacturing method described later using the PPS resin composition, and the temperature is controlled at a constant temperature layer of −40 ° C. for 3 hours. The fuel tank 60 was quickly set in the low temperature impact device 61 as shown in FIG. 6 and the carriage 62 with a pole provided with an iron pole having a diameter of 125 mm was run on the rail 63 and collided with the tank. The energy at the time of collision was set to 1000J. The degree of impact destruction of the tank when colliding was confirmed. The degree of destruction was determined as follows.
◎: Plastic deformation, but not broken ○: Plastic deformation, a crack occurred in the corner of the tank but did not become a through crack ×: Brittle fracture and the crack extended and liquid XX: Fractured brittlely and debris scattered

[Reference Example 1] Preparation of PPS resin A-1 In a 70 liter autoclave equipped with a stirrer and a bottom plug valve, 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide and 2.94 kg of 96% sodium hydroxide were used. (70.63 mol), N-methyl-2-pyrrolidone (NMP) 11.45 kg (115.50 mol), sodium acetate 2.24 kg (27.3 mol) and ion-exchanged water 5.50 kg The mixture was gradually heated to 245 ° C. over about 3 hours while passing nitrogen under pressure, and after distilling 9.77 kg of water and 0.28 kg of NMP, the reaction vessel was cooled to 200 ° C. The residual water content in the system per 1 mol of the charged alkali metal sulfide was 1.06 mol including the water consumed for the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.02 mol per mol of the charged alkali metal sulfide.

  Thereafter, the mixture was cooled to 200 ° C., 10.32 kg (70.20 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and the mixture was stirred at 240 rpm to reach 0.20. The temperature was raised from 200 ° C. to 235 ° C. at a rate of 8 ° C./min, and reacted at 235 ° C. for 40 minutes. Thereafter, the temperature was raised to 270 ° C. at a rate of 0.8 ° C./min and reacted at 270 ° C. for 70 minutes. Then, 2.40 kg (133 mol) of water was injected while cooling from 270 ° C. to 250 ° C. over 15 minutes. . Next, the mixture was gradually cooled from 250 ° C. to 220 ° C. over 75 minutes, and then rapidly cooled to near room temperature, and the contents were taken out.

  The contents were diluted with about 35 liters of NMP, stirred as a slurry at 85 ° C. for 30 minutes, and then filtered through an 80 mesh wire mesh (aperture 0.175 mm) to obtain a solid. The obtained solid was similarly washed and filtered with about 35 liters of NMP. The operation of diluting the obtained solid with 70 liters of ion-exchanged water, stirring at 70 ° C. for 30 minutes, and filtering through an 80 mesh wire net to collect the solid was repeated 5 times in total. The solid thus obtained was dried at 120 ° C. under a nitrogen stream to obtain a dry PPS resin. The obtained PPS resin A-1 had a chloroform extraction amount of 0.1% by weight, a sodium content of 650 ppm, and an MFR of 77 g / 10 min.

[Reference Example 2] Preparation of PPS Resin A-2 Reaction was performed in the same manner as in Reference Example 1, and the solid was obtained by filtration through an 80 mesh wire mesh (aperture 0.175 mm). The obtained solid was similarly washed and filtered with about 35 liters of NMP. The operation of diluting the obtained solid with 70 liters of ion-exchanged water, stirring at 70 ° C. for 30 minutes, and filtering through an 80 mesh wire net to collect the solid was repeated a total of 3 times. The obtained solid and 32 g of acetic acid were diluted with 70 liters of ion exchange water, stirred at 70 ° C. for 30 minutes, filtered through an 80 mesh wire mesh, and further obtained solids were diluted with 70 liters of ion exchange water. The mixture was stirred at 70 ° C. for 30 minutes and then filtered through an 80 mesh wire net to collect a solid. The solid thus obtained was dried at 120 ° C. under a nitrogen stream to obtain a dry PPS resin. The obtained PPS resin A-2 had a chloroform extract amount of 0.1% by weight, a sodium content of 65 ppm, and an MFR of 95 g / 10 min.

Reference Example 3 Preparation of PPS Resin A-3 In a 70 liter autoclave equipped with a stirrer and a bottom plug valve, 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide and 2.94 kg of 96% sodium hydroxide were used. (70.63 mol), N-methyl-2-pyrrolidone (NMP) 11.45 kg (115.50 mol), 1.89 kg (23.1 mol) sodium acetate, and 5.50 kg of ion-exchanged water, The mixture was gradually heated to 245 ° C. over about 3 hours while passing nitrogen under pressure, and after distilling 9.77 kg of water and 0.28 kg of NMP, the reaction vessel was cooled to 200 ° C. The residual water content in the system per 1 mol of the charged alkali metal sulfide was 1.06 mol including the water consumed for the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.02 mol per mol of the charged alkali metal sulfide.

  Thereafter, the mixture was cooled to 200 ° C., 10.42 kg (70.86 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and stirred at 240 rpm. The temperature was raised from 200 ° C. to 270 ° C. at a rate of 6 ° C./min, and reacted at 270 ° C. for 140 minutes. Thereafter, 2.40 kg (133 mol) of water was injected while cooling from 270 ° C. to 250 ° C. over 15 minutes. Next, the mixture was gradually cooled from 250 ° C. to 220 ° C. over 75 minutes, and then rapidly cooled to near room temperature, and the contents were taken out.

  The contents were diluted with about 35 liters of NMP, stirred as a slurry at 85 ° C. for 30 minutes, and then filtered through an 80 mesh wire mesh (aperture 0.175 mm) to obtain a solid. The obtained solid was similarly washed and filtered with about 35 liters of NMP. The operation of diluting the obtained solid with 70 liters of ion-exchanged water, stirring at 70 ° C. for 30 minutes, and filtering through an 80 mesh wire net to collect the solid was repeated 5 times in total. The solid thus obtained was dried at 120 ° C. under a nitrogen stream to obtain a dry PPS resin. The obtained PPS resin A-3 had a chloroform extraction amount of 0.2% by weight, a sodium content of 550 ppm, and an MFR of 300 g / 10 min.

[Reference Example 4] Preparation of PPS resin A-4 In a 70 liter autoclave equipped with a stirrer and a bottom plug valve, 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide and 2.91 kg of 96% sodium hydroxide were used. (69.80 mol), N-methyl-2-pyrrolidone (NMP) 11.45 kg (115.50 mol), sodium acetate 2.24 kg (27.3 mol) and ion-exchanged water 10.5 kg The mixture was gradually heated to 245 ° C. over about 3 hours while passing nitrogen under pressure, and after distilling out 14.78 kg of water and 0.28 kg of NMP, the reaction vessel was cooled to 200 ° C. The residual water content in the system per 1 mol of the charged alkali metal sulfide was 1.06 mol including the water consumed for the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.02 mol per mol of the charged alkali metal sulfide.

  Thereafter, the mixture was cooled to 200 ° C., 10.34 kg (70.32 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and stirred at 240 rpm. The temperature was raised from 200 ° C. to 235 ° C. at a rate of 8 ° C./min, and reacted at 235 ° C. for 40 minutes. After that, the temperature was raised to 270 ° C. at a rate of 0.8 ° C./min and reacted at 270 ° C. for 70 minutes. Then, the bottom plug valve of the autoclave was opened, and the contents were put in a container equipped with a stirrer for 15 minutes while being pressurized with nitrogen. Flush and stir for a while at 250 ° C. to remove most of the NMP.

  The obtained solid and 76 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 70 ° C. for 30 minutes, and then suction filtered through a glass filter. Next, 76 liters of ion-exchanged water heated to 70 ° C. was poured into a glass filter, and suction filtered to obtain a cake.

  The obtained cake and 90 liters of ion-exchanged water were charged into an autoclave equipped with a stirrer, and the interior of the autoclave was replaced with nitrogen, and then the temperature was raised to 192 ° C. and held for 30 minutes. Thereafter, the autoclave was cooled and the contents were taken out.

  The contents were subjected to suction filtration with a glass filter, and then 76 liters of ion-exchanged water at 70 ° C. was poured into the contents, followed by suction filtration to obtain a cake. The obtained cake was dried at 120 ° C. under a nitrogen stream to obtain a dry PPS resin. The obtained PPS resin A-4 had a chloroform extraction amount of 2.4% by weight, a sodium content of 1050 ppm, and an MFR of 180 g / 10 min.

[Examples 1-7, Comparative Examples 1-5]
After dry blending each of the components shown below in the proportions shown in Tables 1 and 2, using a TEX30 type twin screw extruder manufactured by Nippon Steel Works, the cylinder temperature of the plasticizing part was 290 ° C., and the cylinder temperature of the kneading part was The screw element in which the flight tip part was inclined at a spiral angle of 75 degrees as a low heat generation kneading element in Examples 1-6 and Comparative Examples 1-5 were set at 230 ° C. and the screw rotation speed at 300 rpm. In Example 7, melt kneading was performed using a screw in which 6 units of ordinary kneading discs were introduced into the screw kneading part, and a gut discharged from the die was used. Immediately cool in a water bath, pelletize with a strand cutter, dry at 110 ° C overnight and PPS resin composition It was obtained.

Production of Fuel Tank Using the PPS resin compositions of Examples 1 to 7 and Comparative Examples 1 to 5, fuel tanks as shown in FIG. 3 were produced. This fuel tank is composed of an inverted bottomed cup-shaped upper shell 4 having an open bottom surface and a bottomed cup-shaped lower shell 5 having an open top surface as a split molded body formed by injection molding. It is formed by welding.

  The upper shell 4 and the lower shell 5 as the divided molded bodies were injection molded at a resin temperature of 310 ° C. of the PPS resin composition, an injection rate of 200 ml / sec, and a mold temperature of 60 ° C. The general thickness of the upper shell 4 and the lower shell 5 is about 3 mm, and the inner dimensions are about 350 mm wide × about 450 mm deep. The depth from the lower surface opening of the upper shell 4 to the inner top surface is about 125 mm, and the depth from the upper surface opening of the lower shell 5 to the inner bottom surface is about 125 mm.

  The upper shell 4 and the lower shell 5 obtained by injection molding were brought into contact with each other at the joining surfaces of the flange portions facing each other, and were hot-plate welded. Specifically, it was set in a hot plate welding machine, and heat welding was performed at a hot plate temperature of 310 ° C., a melting allowance of 2 mm, a melting time of 60 sec, an intermediate time of 5 sec, an indentation allowance of 1.5 mm, and a welding time of 15 sec. The welded portion 6 is a portion where the lower end surface 41 of the upper shell 4 (with a flange 42 whose outer periphery protrudes outward in the illustrated example) and the upper end surface 51 (also with the flange 52) of the lower shell 5 are abutted. .

  Fastening portions 43 and 53 into which a reinforcing post 7 (made by POM) having a diameter of 40 mm is fitted are provided on the inner surface of the upper shell 4 and on the inner surface of the lower shell 5, respectively. When the lower end surface 41 of the upper shell 4 and the upper end surface 51 of the lower shell 5 are heated to form a butt weld portion, the reinforcing column 7 is fitted into the column fastening portions 43 and 53 of the upper shell 4 and the lower shell 5, respectively.

  A maintenance hole 8 of φ120 mm is formed on the upper surface (general part) of the upper shell 4, and a maintenance hole cap 10 (made of POM) is attached to a mounting flange portion 44 of the maintenance hole 8 via an O-ring 9 (made of fluoro rubber). The maintenance hole cap 10 was attached by a bayonet method in which the constructed bayonet claw 11 was inserted into the flange portion 44 and rotated and attached repeatedly, and a fuel tank was obtained.

The (a) PPS resin used in the examples and comparative examples is as follows.
A-1: PPS resin polymerized by the method described in Reference Example A-2: PPS resin polymerized by the method described in Reference Example A-3: PPS resin A- polymerized by the method described in Reference Example 3 4: PPS resin polymerized by the method described in Reference Example 4

Similarly, (b) the epoxy group-containing olefin copolymer is as follows.
B-1: Copolymer of ethylene / glycidyl methacrylate = 92/8 (weight ratio) (Sumitomo Chemical "Bond First" ETX-6)
B-2: Copolymer of ethylene / glycidyl methacrylate = 88/12 (weight ratio) (Sumitomo Chemical "bond first" BF-E)

Similarly, the (c) ethylene / α-olefin copolymer is as follows.
C-1: MFR = 0.5 g / 10 min (190 ° C., 2.16 kg load), ethylene / 1-butene copolymer having a density of 0.861 g / cm ³ (“Tafmer” TX-610 manufactured by Mitsui Chemicals)
C-2: MFR = 0.5 g / 10 min (190 ° C., 2.16 kg load), ethylene / 1-octene copolymer having a density of 0.868 g / cm ³ (“engage” ENR8150 manufactured by Dow Chemical)

The following elastomers were used in the comparative examples.
D-1: Ethylene / propylene / diene copolymer (Mitsui Chemicals Mitsui EPT3045)

  According to the present invention, it is possible to obtain a fuel tank that is excellent in molding processability and has low fuel swellability, pressure resistance, and low temperature impact resistance.

1 (a) PPS resin 2 (b) Epoxy group-containing olefin copolymer 3 (c) Ethylene / α-olefin copolymer 4 Upper shell 5 Lower shell 6 Welded portion 7 Reinforcing strut 8 Maintenance hole 9 O-ring 10 Maintenance hole cap 11 Bayonet claw 41 Lower end face 42 Flange 43 Strut fastening part 44 Maintenance hole mounting flange 45 Internal diameter of maintenance hole 51 Upper end face 52 Flange 53 Post fastening part 54 Destruction part of post fastening part 60 Fuel tank 61 Low temperature impact test device 62 Pole Attached cart 63 rail

Claims (7)

A fuel tank obtained by melt-molding a polyphenylene sulfide resin composition, wherein the polyphenylene sulfide resin composition comprises (a) 78 to 88% by weight of a polyphenylene sulfide resin, and (b) an epoxy group-containing olefin copolymer 1 to 21. And (c) 1 to 21% by weight of an ethylene / α-olefin copolymer obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms (however, the total of each component is 100% by weight) to.) a, wherein (a) polyphenylene sulfide chloroform extraction amount of 0.01 to 1 wt% of the resin, and Ri der sodium content is 300ppm or more, the fuel tank and having a reinforcing strut structure.   2. The fuel tank according to claim 1, wherein the (a) polyphenylene sulfide resin has a melt flow rate of 50 to 200 g / 10 minutes measured at 315.5 ° C. under a load of 5000 g in accordance with ASTM-D1238.   The fuel tank according to claim 1 or 2, wherein the (a) polyphenylene sulfide resin is obtained by a quench method.   4. The epoxy group-containing olefin copolymer (b) is a copolymer of 90 to 99% by weight of ethylene and 1 to 10% by weight of α, β-unsaturated carboxylic acid glycidyl ester. A fuel tank according to any one of the above.   While the (a) polyphenylene sulfide resin forms a continuous phase, the shell phase of the (b) epoxy group-containing olefin polymer includes the core phase of the (c) ethylene / α-olefin copolymer. The fuel tank according to any one of claims 1 to 4, wherein a dispersed type phase is formed and an average dispersed particle diameter is 1 to 200 nm.   The fuel tank according to any one of claims 1 to 5, wherein a part of or all of the reinforcing structure and components constituting the fuel tank are integrally formed. The fuel tank, the fuel tank according to any one of claims 1 to 6, characterized in that it has a maintenance hole.

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