JP5146124B2 - Fuel tube - Google Patents

Description

  The present invention relates to a fuel tube. Specifically, a polyamide resin layer that is excellent in fuel impermeability and fuel resistance, has a wide moldable temperature range, has excellent moldability, and has low water absorption, chemical resistance, hydrolysis resistance, etc. In particular, it relates to a multilayer fuel tube for automobiles.

  Conventional fuel tubes for automobiles are made of metal, but in order to reduce vehicle weight for the purpose of improving fuel efficiency, resin tubes are also put to practical use as fuel tubes for automobiles.

  However, when the automobile fuel tube is made of resin, there is a problem that the wall permeability of gasoline, alcohol / gasoline mixed fuel, etc. is higher than that of metal.

  An automobile fuel tube made of polyamide resin is used, and it has been proposed to contain a layered silicate in order to suppress the fuel permeability of the polyamide resin (Patent Document 1). However, higher fuel impermeability is required.

  Also in automobile fuel tubes, polyamide resins have been pointed out to have problems such as changes in physical properties due to water absorption, acid, high-temperature alcohol, deterioration in hot water, etc., and more fuel resistance, dimensional stability, There is also a need for polyamides with excellent chemical resistance.

  Regarding water absorption, a polyamide resin using oxalic acid as a dicarboxylic acid component is called a polyoxamide resin, and is known to have a higher melting point and lower water absorption than other polyamide resins having the same amino group concentration (Patent Literature). 2) Expected to be used in fields where conventional polyamides are difficult to use due to changes in physical properties due to water absorption.

  So far, polyoxamide resins using various aliphatic linear diamines as diamine components have been proposed. However, for example, a polyoxamide resin using 1,6-hexanediamine as a diamine component has a melting point (about 320 ° C.) higher than the thermal decomposition temperature (1% weight loss temperature in nitrogen; about 310 ° C.) (non-patent document). 1) Melt polymerization and melt molding were difficult and could not withstand practical use.

  For a polyoxamide resin whose diamine component is 1,9-nonanediamine (hereinafter abbreviated as PA92), L. Franco et al. Discloses a production method and its crystal structure when diethyl oxalate is used as the oxalic acid source ( Non-patent document 2). The PA 92 obtained here is a polymer having an intrinsic viscosity of 0.97 dL / g and a melting point of 246 ° C., but only a low molecular weight substance that cannot form a tough molded article is obtained. Further, it is shown that PA92 having an intrinsic viscosity of 0.99 dL / g and a melting point of 248 ° C. was produced when dibutyl oxalate was used as the dicarboxylic acid ester (Patent Document 3). In this case as well, there is a problem that only a low molecular weight body that cannot be formed into a tough molded body is obtained.

  In prior literature, there is no specific disclosure of a polyoxamide resin using two kinds of diamines of 1,9-nonanediamine and 2-methyl-1,8-octanediamine as a diamine component in a specific ratio.

S. W. Shalaby., J. Polym. Sci., 11, 1 (1973) L. Franco et al., Macromolecules., 31, 3912 (1988) Patent No. 3067891 JP 2006-57033 A Japanese National Patent Publication No. 5-506466

  The problems to be solved by the present invention are polyamides that are excellent in fuel impermeability and fuel resistance, have a wide moldable temperature range and excellent melt moldability, and are excellent in low water absorption, chemical resistance, hydrolysis resistance, etc. The object is to provide a fuel tube having a layer of resin.

  As a result of intensive studies to solve the above problems, the present inventors have used oxalic acid diester as the oxalic acid source, and the diamine component comprises 1,9-nonanediamine and 2-methyl-1,8-octanediamine. And a mixture in which the molar ratio of 1,9-nonanediamine and 2-methyl-1,8-octanediamine is 1:99 to 99: 1, fuel impermeability and fuel resistance are improved, A polyamide resin having a large difference in melting point and thermal decomposition temperature, excellent melt moldability, and low water absorption, chemical resistance, and hydrolysis resistance can be obtained. Therefore, a fuel comprising this polyamide resin layer According to the tube, it has been found that the above-described object can be achieved, and the present invention has been completed.

  According to the present invention, it is excellent in fuel impermeability and fuel resistance, can be increased in molecular weight by melt polymerization, has a wide moldable temperature range of 50 ° C. or more, has excellent melt moldability, and has low water absorption. Provided is a fuel tube including a polyamide resin layer having excellent properties, chemical resistance, and hydrolysis resistance.

(1) Constituent Component of Polyamide Resin The polyamide of the polyamide resin layer constituting the fuel tube of the present invention has a dicarboxylic acid component composed of oxalic acid, and a diamine component of 1,9-nonanediamine and 2-methyl-1,8-octanediamine. And a polyamide resin which is a diamine mixture having a molar ratio of 1,9-nonanediamine and 2-methyl-1,8-octanediamine of 1:99 to 99: 1.

  As the oxalic acid source used for the production of polyamide, oxalic acid diester is used, and there is no particular limitation as long as it has reactivity with an amino group. Dimethyl oxalate, diethyl oxalate, di-n-oxalate (or i- ) Succinic acid diesters of aliphatic monohydric alcohols such as propyl, di-n- (or i-, or t-) butyl oxalate, oxalic acid diesters of alicyclic alcohols such as dicyclohexyl oxalate, and oxalic acid diesters of aromatic alcohols such as diphenyl oxalate Etc.

  Among the above oxalic acid diesters, oxalic acid diesters of aliphatic monohydric alcohols having more than 3 carbon atoms, oxalic acid diesters of alicyclic alcohols, and oxalic acid diesters of aromatic alcohols are preferred, and among them, dibutyl oxalate and diphenyl oxalate are particularly preferred.

  As the diamine component, a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine is used. Furthermore, the molar ratio of the 1,9-nonanediamine component and the 2-methyl-1,8-octanediamine component is 1:99 to 99: 1, preferably 5:95 to 95: 5, more preferably 5: 95-40: 60 or 60: 40-95: 5, especially 5: 95-30: 70 or 70: 30-90: 10. By copolymerizing 1,9-nonanediamine and 2-methyl-1,8-octanediamine in the above-mentioned specific amount, it has excellent fuel impermeability, a wide moldable temperature range, excellent melt moldability, and low water absorption. Polyamide having excellent properties, chemical resistance, hydrolysis resistance and the like can be obtained.

(2) Production of polyamide resin The novel polyamide resin used in the fuel tube of the present invention can be produced by any method known as a method for producing polyamide. According to the study by the present inventors, it can be obtained by subjecting diamine and oxalic acid diester to a polycondensation reaction in a batch or continuous manner. Specifically, it is preferable to carry out in the order of (i) pre-polycondensation step and (ii) post-polycondensation step as shown by the following operations.

  (I) Pre-polycondensation step: First, the inside of the reactor is purged with nitrogen, and then diamine (diamine component) and oxalic acid diester (oxalic acid source) are mixed. When mixing, a solvent in which both the diamine and the oxalic acid diester are soluble may be used. The solvent in which both the diamine component and the oxalic acid source are soluble is not particularly limited, but toluene, xylene, trichlorobenzene, phenol, trifluoroethanol, and the like can be used, and particularly, toluene can be preferably used. For example, after heating the toluene solution which melt | dissolved diamine to 50 degreeC, oxalic acid diester is added with respect to this. At this time, the charging ratio of the oxalic acid diester and the diamine is oxalic acid diester / the diamine, 0.8 to 1.5 (molar ratio), preferably 0.91 to 1.1 (molar ratio), more preferably 0. .99 to 1.01 (molar ratio).

  The temperature in the reactor charged in this way is increased under normal pressure while stirring and / or nitrogen bubbling. The reaction temperature is preferably controlled so that the final temperature reaches 80 to 150 ° C., preferably 100 to 140 ° C. The reaction time at the final temperature reached is 3-6 hours.

  (Ii) Post-polycondensation step: In order to further increase the molecular weight, the polymer produced in the pre-polycondensation step is gradually heated in the reactor under normal pressure. In the temperature rising process, the final temperature of the prepolycondensation step, that is, from 80 to 150 ° C, is finally 220 ° C to 300 ° C, preferably 230 ° C to 280 ° C, more preferably 240 ° C to 270 ° C. Let reach the range. It is preferable to carry out the reaction for 1 to 8 hours including the temperature raising time, preferably 2 to 6 hours. Furthermore, in the post-polymerization step, polymerization can be performed under reduced pressure as necessary. The preferable final ultimate pressure in the case of performing the vacuum polymerization is less than 0.1 MPa to 13.3 Pa.

The specific example of the manufacturing method of the polyamide resin used for this invention is demonstrated.
First, the raw oxalic acid diester is charged into the container. The container is not particularly limited as long as it can withstand the temperature and pressure of the polycondensation reaction to be performed later. Thereafter, the container is heated to a temperature at which it is mixed with the raw material diamine, and then the diamine is injected to start the polycondensation reaction. The temperature at which the raw materials are mixed is not particularly limited as long as it is a temperature that is not lower than the melting point and lower than the boiling point of the oxalic acid diester and diamine, and the polyoxamide generated by the polycondensation reaction of the oxalic acid diester and diamine is not thermally decomposed. For example, it consists of a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine, and the molar ratio of 1,9-nonanediamine and 2-methyl-1,8-octanediamine is 1:99 to 99: In the case of a polyoxamide resin using diamine 1 and dibutyl oxalate as raw materials, the mixing temperature is preferably 15 ° C to 240 ° C. Further, the molar ratio of 1,9-nonanediamine to 2-methyl-1,8-octanediamine is 5:95 to 90:10, which is liquid at room temperature or liquefied only by heating to about 40 ° C., so that it is easy to handle. Therefore, it is more preferable. When the mixing temperature is equal to or higher than the boiling point of the alcohol produced by the condensation reaction, it is desirable to use a container equipped with a device for distilling and condensing the alcohol. In addition, when pressure polymerization is performed in the presence of an alcohol generated by a condensation reaction, a pressure vessel is used. The charging ratio of oxalic acid diester and diamine is oxalic acid diester / diamine as described above, 0.8 to 1.2 (molar ratio), preferably 0.91 to 1.09 (molar ratio), more preferably 0.98. -1.02 (molar ratio).

  Next, the inside of the container is heated to a temperature not lower than the melting point of the polyoxamide resin and not higher than the temperature at which it is not thermally decomposed. For example, a diamine and shu comprising 1,9-nonanediamine and 2-methyl-1,8-octanediamine, and the molar ratio of 1,9-nonanediamine and 2-methyl-1,8-octanediamine is 85:15. In the case of a polyoxamide resin using dibutyl acid as a raw material, the melting point is 235 ° C., so it is preferable to raise the temperature from 240 ° C. to 280 ° C. (pressure is 2 MPa to 4 MPa). While distilling off the produced alcohol, the polycondensation reaction is continued under an atmospheric pressure of nitrogen or reduced pressure as necessary. When the raw materials are mixed in a pressure vessel and subjected to pressure polymerization in the presence of an alcohol produced by a condensation reaction, the pressure is first released while the produced alcohol is distilled off. Thereafter, the polycondensation reaction is continued under an atmospheric pressure of nitrogen or reduced pressure as necessary. The preferable final pressure in the case of carrying out the vacuum polymerization is 760 to 0.1 Torr. The temperature is preferably 240 to 280 ° C. The alcohol is cooled and liquefied by a water-cooled condenser and recovered.

(3) Properties and properties of polyamide resin There is no particular limitation on the molecular weight of the polyamide resin used in the polyamide resin layer of the fuel tube of the present invention, but 96% concentrated sulfuric acid is used as a solvent and the polyamide resin concentration is 1.0 g / dl. Using a 96% concentrated sulfuric acid solution, the relative viscosity ηr measured at 25 ° C. is in the range of 1.8 to 6.0. Preferably it is 2.0-5.5, and 2.5-4.5 is especially preferable. If ηr is lower than 1.8, the molded product becomes brittle and the physical properties deteriorate. On the other hand, if ηr is higher than 6.0, the melt viscosity becomes high, and the molding processability deteriorates.

  The polyamide resin used for the polyamide resin layer of the fuel tube of the present invention uses oxalic acid as the carboxylic acid component and copolymerizes 1,9-nonanediamine and 2-methyl-1,8-octanediamine as the diamine component, thereby producing oxalic acid. It is possible to increase the relative viscosity, that is, to increase the molecular weight, as compared with a polyamide comprising 1,9-nonanediamine. The moldable temperature range represented by the difference (Td−Tm) between the 1% weight loss temperature (hereinafter abbreviated as Td) and the melting point (hereinafter abbreviated as Tm), which is a substantial thermal decomposition index, is oxalic acid. And a polyamide composed of 1,9-nonanediamine, preferably 50 ° C. or higher, more preferably 60 ° C. or higher, and further 90 ° C. or higher. The polyamide resin of the present invention has a Td of preferably 280 ° C. or higher, more preferably 300 ° C. or higher, and still more preferably 320 ° C. or higher, and has high heat resistance.

(4) Components that can be blended in the polyamide resin layer The polyamide resin used in the fuel tube of the present invention can be mixed with other dicarboxylic acid components as long as the effects of the present invention are not impaired. Examples of dicarboxylic acid components other than succinic acid include malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, 3, Aliphatic dicarboxylic acids such as 3-diethylsuccinic acid, azelaic acid, sebacic acid and suberic acid, alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid, and terephthalic acid , Isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, dibenzoic acid Acid, 4,4′-oxydibenzoic acid, diphenylmethane-4,4′-dicarboxylic acid, diphenyls Hong-4,4'-dicarboxylic acid, 4,4'-biphenyl and the like alone aromatic dicarboxylic acids such as dicarboxylic acids, or may be added to any mixture thereof during the polycondensation reaction. Furthermore, polyvalent carboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid can be used as long as melt molding is possible. The amount of the dicarboxylic acid component other than oxalic acid is preferably 5 mol% or less based on the total dicarboxylic acid component.

  In addition, other diamine components can be mixed in the polyamide resin used in the fuel tube of the present invention within a range not impairing the effects of the present invention. Examples of diamine components other than 1,9-nonanediamine and 2-methyl-1,8-octanediamine include ethylenediamine, propylenediamine, 1,4-butanediamine, 1,6-hexanediamine, and 1,8-octanediamine. 1,10-decanediamine, 1,12-dodecanediamine, 3-methyl-1,5-pentanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1 , 6-hexanediamine, aliphatic diamines such as 5-methyl-1,9-nonanediamine, alicyclic diamines such as cyclohexanediamine, methylcyclohexanediamine and isophoronediamine, p-phenylenediamine, m-phenylenediamine, p -Xylenediamine, m-xylenediamine, 4,4'-di Mino diphenylmethane, 4,4'-diaminodiphenyl sulfone, 4,4'-and aromatic diamines, such as diaminodiphenyl ether by itself, or may be added to any mixture thereof during the polycondensation reaction. The blending amount of diamine components other than 1,9-nonanediamine and 2-methyl-1,8-octanediamine is preferably 5 mol% or less based on the total diamine components.

  In addition, the polyamide resin of the polyamide resin layer of the present invention can be mixed with other polyoxamides, polyamides such as aromatic polyamides, aliphatic polyamides, and alicyclic polyamides as long as the effects of the present invention are not impaired. is there. Furthermore, thermoplastic polymers other than polyamide and elastomers can be blended. However, the polyamide resin layer of the present invention preferably contains at least 50% by mass of the novel polyamide resin provided by the present invention on the basis of the resin component and further on the basis of the polyamide resin layer.

  In addition, the polyamide resin layer of the present invention has high fuel impermeability even if it does not contain layered silicate, but it can further improve fuel impermeability including layered silicate.

  Examples of the layered silicate include a layered phyllosilicate composed of a layer of magnesium silicate or aluminum silicate, and the length of one side is 0.002 to 1 μm and the thickness is 6 to 20 mm. These flat plates form layers.

  Specific examples of the layered phyllosilicate include smectite clay minerals such as montmorillonite, saponite, beidellite, nontronite, hectorite, and stevensite, vermiculite, and halosite. These may be natural products or synthetic products.

  When the layered silicate is dispersed in the composition, it keeps an average interlayer distance of 20 mm or more and is uniformly dispersed. Here, the interlayer distance refers to the distance between the centers of gravity of the layered silicate flat plates, and uniformly dispersed means that the multilayered layers of layered silicate flat plates that are overlapped on average five layers or less are parallel, or It means a state in which 50% by mass or more, preferably 70% by mass or more, is dispersed without forming a local lump in a state where random or parallel and random are mixed.

  0.05-10 mass parts is preferable with respect to 100 mass parts of polyamide resins, and, as for the compounding quantity of layered silicate, 0.05-5 mass parts is more preferable. If it is less than 0.05 parts by mass, the fuel permeation suppressing effect is not sufficient, and if it exceeds 10 parts by mass, molding may be difficult, and impact strength and flexibility may be reduced.

  The polyamide resin used for the fuel tube of the present invention preferably contains a plasticizer. As the plasticizer, for example, benzenesulfonic acid butyramide, ester of p-hydroxybenzoic acid and a linear or branched alcohol having 6 to 21 carbon atoms (for example, 2-ethylhexyl, p-hydroxybenzoate) or the like is used. it can.

  As for the compounding quantity of a plasticizer, 0-30 mass parts is preferable with respect to 100 mass parts of polyamide resins. When the amount of the plasticizer exceeds 30 parts by mass, the breaking pressure of the tube is lowered, and there is a possibility that a bleed out problem may occur.

  For the polyamide resin layer used in the present invention, if necessary, other fillers, reinforcing materials, heat-resistant materials, stabilizers such as copper compounds, colorants, ultraviolet absorbers, light stabilizers, antioxidants, An antistatic agent, a flame retardant, a crystallization accelerator, a plasticizer, a lubricant, and the like can be added during or after the polycondensation reaction.

(5) Configuration and Production of Fuel Tube The fuel tube of the present invention includes the polyamide resin layer described above, and can be used as a single-layer tube. It is preferably used as a multilayer tube laminated with a resin layer. In practical automotive fuel tubes, many multilayer tubes are used.

  As another resin layer used for the multilayer fuel tube for automobiles of the present invention, a layer made of a resin obtained by blending the above plasticizer with a fluororesin, a high density polyethylene resin, a polyamide 11 resin or a polyamide 12 resin is preferable. As the layer serving as the main skeleton of the outermost layer or the other layers, a novel polyamide resin (PA92) provided by the present invention, a polyamide 11 resin, a polyamide 12 resin, or a material obtained by adding a plasticizer to the polyamide resin is used. Is preferred.

  Examples of the fluororesin include polytetrafluoroethylene (PTEF), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF). Further, it may be a resin partially containing chlorine, such as polychlorofluoroethylene (PCTFE), or a copolymer with ethylene or the like.

  As the high-density polyethylene resin, those having an average molecular weight of about 200,000 to 300,000 are preferable in consideration of gasoline resistance. The high-density polyethylene resin has a low-temperature embrittlement temperature of −80 ° C. or less and excellent low-temperature impact resistance.

  Moreover, you may provide another resin layer through an contact bonding layer, when adhesiveness with the said composition layer is bad. In addition, the other resin layer may not be a single layer, and may be a laminate of several layers.

  When the fuel tube of the present invention is a multilayer tube, the thickness of the polyamide resin layer of the present invention is preferably 20 to 80%, more preferably 30 to 70% of the wall thickness of the tube. If it is less than 20%, the fuel impermeability of the tube may not be sufficient. Although the upper limit is not limited, 70% or less is preferable in order to satisfy many required characteristics required for the fuel tube at the same time.

  The outer diameter of the multilayer fuel tube for automobiles can be designed in consideration of the flow rate of fuel gasoline, and the wall thickness is the thickness that does not increase gasoline permeability and can maintain the normal tube breaking pressure, and the tube Although it can be designed to be thin enough to maintain flexibility with a satisfactory degree of ease of assembly work and vibration resistance during use, the outer diameter is preferably 4 mm to 15 mm, and the wall thickness is 0 .5 mm to 2 mm is preferable.

  The fuel tube of the present invention preferably contains conductive carbon black in at least one of the constituent layers in an amount of 3 to 30% by weight based on the composition of the layer.

  Examples of the conductive carbon black include acetylene black and ketjen black. Among them, those having a good chain structure and a high aggregation density are preferable.

  As a method for producing the fuel tube of the present invention, extrusion molding is preferably used, and as a method for producing a multilayer fuel tube, for example, extrusion is performed from a number of extruders corresponding to the number of constituent layers or the number of materials. The molten resin is introduced into one multi-layer tube die, and each layer is bonded in the die or immediately after exiting the die, and then manufactured in the same manner as normal tube forming. Also, a single-layer tube is once formed. Then, a method of coating another layer on the outside or inside of the tube can be mentioned.

  The fuel tube of the present invention is excellent in fuel impermeability and fuel resistance, can be increased in molecular weight by melt polymerization, has a wide moldable temperature range of 50 ° C. or more, has excellent melt moldability, and is low Since it is excellent in water absorption, chemical resistance and hydrolysis resistance, it is particularly suitably used as a fuel tube for automobiles.

[Physical property measurement, molding, evaluation method]
Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, the measurement in an Example was performed with the following method.

(1) Relative viscosity (ηr)
ηr was measured at 25 ° C. using an Ostwald viscometer using a 96% polyamide sulfuric acid solution (concentration: 1.0 g / dl).

(2) Melting point (Tm) and crystallization temperature (Tc)
Tm and Tc were measured under a nitrogen atmosphere using a PYRIS Diamond DSC manufactured by PerkinELmer. The temperature was raised from 30 ° C. to 270 ° C. at a rate of 10 ° C./min (referred to as a temperature rise first run), held at 270 ° C. for 3 minutes, and then lowered to −100 ° C. at a rate of 10 ° C./min (temperature fall first Then, the temperature was raised to 270 ° C. at a rate of 10 ° C./min (called a temperature raised second run). From the obtained DSC chart, the exothermic peak temperature of the temperature decrease first run was Tc, and the endothermic peak temperature of the temperature increase second run was Tm.

(3) 1% weight loss temperature (Td)
Td was measured by thermogravimetric analysis (TGA) using THERMOGRAVIMETRIC ANALYZER TGA-50 manufactured by Shimadzu Corporation. The temperature was raised from room temperature to 500 ° C. at a rate of 10 ° C./min under a nitrogen stream of 20 ml / min, and Td was measured.

(4) Melt viscosity Melt viscosity was measured by attaching a 25 mm cone plate to a melt viscoelasticity measuring device ARES manufactured by TA Instruments Japan Co., Ltd., at 250 ° C. in nitrogen and at a shear rate of 0.1 s ⁻¹ . Measured under conditions.

(5) Film formation Film formation was performed using a vacuum press TMB-10 manufactured by Toho Machinery Co., Ltd. After being melted by heating at 260 ° C. in a reduced pressure atmosphere of 500 to 700 Pa (290 ° C. when nylon 66 is used, 230 ° C. when nylon 12 is used) for 5 minutes, the film was formed by pressing at 5 MPa for 1 minute. Next, the reduced-pressure atmosphere was returned to normal pressure, and then cooled and crystallized at room temperature of 5 MPa for 1 minute to obtain a film.

(6) Water absorption rate (saturated water absorption rate, equilibrium water absorption rate)
A film (dimensions: 20 mm × 10 mm, thickness 0.25 mm; weight about 0.05 g) obtained by molding the polyamide resin under the conditions of (5) is immersed in ion exchange water at 23 ° C., and the film is taken out every predetermined time. The weight of the film was measured. When the rate of increase in the film weight continues three times within the range of 0.2% or less, it is judged that the absorption of water into the polyamide resin film has reached saturation, and the weight of the film before being immersed in water (Xg) From the weight (Yg) of the film when reaching saturation, the saturated water absorption (%) was calculated by the formula (1).
Saturated water absorption (%) = 100 (Y−X) / X (1)
The water absorption rate (equilibrium water absorption rate) calculated by the formula (1) from the weight (Yg) immediately after forming the film and the weight (Yg) when the film reached equilibrium at a humidity of 65% and a temperature of 23 ° C. ) As the wet water absorption.

(7) Chemical resistance After the polyamide hot press film obtained according to the present invention was immersed in the chemicals listed below for 7 days, changes in the weight residual ratio (%) and appearance of the film were observed. In each of concentrated hydrochloric acid, 64% sulfuric acid, and glacial acetic acid solutions, tests were performed on samples immersed at 23 ° C.

(8) Hydrolysis resistance The polyamide hot press film obtained by the present invention is put in an autoclave, and water (pH = 7), 0.5 mol / l sulfuric acid (pH = 1), 1 mol / l sodium hydroxide aqueous solution (pH). = 14), the residual weight ratio (%) and appearance change after treatment at 121 ° C. for 60 minutes were examined.

(9) Mechanical properties [1] to [4] shown below are measured using the following test piece with a resin temperature of 260 ° C. (290 ° C. when nylon 66 is used, 230 ° C. when nylon 12 is used). Molding was carried out by injection molding at a mold temperature of 80 ° C. The ones evaluated at 23 ° C. without conditioning immediately after molding are shown in the table as dry, and the ones evaluated at 23 ° C. after conditioning at a humidity of 65% and a temperature of 23 ° C. after molding are shown in the table.
[1] Tensile test (tensile yield point strength): Measured in accordance with ASTM D638 using a Type I test piece described in ASTM D638.
[2] Bending test (flexural modulus): Measured at 23 ° C. in accordance with ASTM D790 using a test piece having dimensions of 127 mm × 12.7 mm × 3.2 mm.
[3] Izod impact strength: Measured at 23 ° C. in accordance with ASTM D256 using a test piece having dimensions of 127 mm × 12.7 mm × 3.2 mm.
[4] Deflection temperature under load: Measured at a load of 1.82 MPa in accordance with ASTM D648 using a test piece having a test piece size of 127 mm × 12.7 mm × 3.2 mm.

(10) Tube low-temperature impact resistance As an apparatus for forming a multilayer tube, it is equipped with an inner layer extruder, an intermediate layer extruder and an outer layer extruder. The resin discharged from these three extruders is collected by an adapter into a tube shape. A multi-layer tube having an inner diameter of 6 mm and an outer diameter of 8 mm was prepared using an apparatus comprising a die to be molded, a sizing die for cooling the tube and controlling the dimensions, and a take-up machine. The thicknesses of the inner layer, intermediate layer and outer layer of the tube are shown in Table 2. The low temperature impact property of the obtained multilayer tube was measured according to SAE J844.

(11) Fuel permeability Seal one end of the tube cut to 30cm, put alcohol gasoline mixed with commercial gasoline and ethyl alcohol 1: 1, and seal the other end, and then measure the whole weight. Then, the test tube was put in an oven at 60 ° C., and the change in weight (g / 24 hours) was measured to evaluate the fuel permeability.

(12) Fuel resistance The surface of the tube after the fuel permeation test was visually observed to check for cracks.

[Resin Production Example 1: Production of PA92C-1]
Oxalic acid in a pressure vessel with a volume of 150 liters equipped with a stirrer, thermometer, torque meter, pressure gauge, raw material inlet directly connected with a diaphragm pump, nitrogen gas inlet, pressure relief port, pressure regulator and polymer outlet The operation of charging 28.40 kg (140.4 mol) of dibutyl, pressurizing the inside of the pressure vessel to 0.5 MPa with nitrogen gas having a purity of 99.9999%, and then releasing nitrogen gas to normal pressure is performed 5 After repeated nitrogen substitution, the system was heated while stirring under a sealing pressure. After adjusting the temperature of dibutyl oxalate to 100 ° C. over about 30 minutes, 18.89 kg (119.3 mol) of 1,9-nonanediamine and 3.34 kg (21.1 mol) of 2-methyl-1,8-octanediamine were obtained. ) (Molar ratio of 1,9-nonanediamine to 2-methyl-1,8-octanediamine is 85:15) into a reaction vessel by a diaphragm pump at a flow rate of 1.49 liters / minute for about 17 minutes. The temperature was raised simultaneously with the supply. The internal pressure in the pressure vessel immediately after the supply increased to 0.35 MPa by butanol generated by the polycondensation reaction, and the temperature of the polycondensate increased to about 170 ° C. Thereafter, the temperature was raised to 235 ° C. over 1 hour. Meanwhile, the internal pressure was adjusted to 0.5 MPa while extracting the generated butanol from the pressure relief port. Immediately after the temperature of the polycondensate reached 235 ° C., butanol was extracted from the pressure release port over about 20 minutes, and the internal pressure was brought to normal pressure. From the normal pressure, the temperature was raised while flowing nitrogen gas at 1.5 liters / minute, the temperature of the polycondensate was brought to 260 ° C. over about 1 hour, and the reaction was carried out at 260 ° C. for 4.5 hours. . Thereafter, stirring was stopped, the inside of the system was pressurized to 1 MPa with nitrogen and allowed to stand for about 10 minutes, then released to an internal pressure of 0.5 MPa, and the polycondensate was extracted in a string form from the lower outlet of the pressure vessel. The string-like polymer was immediately cooled with water, and the water-cooled string-like resin was pelletized with a pelletizer. The obtained polyamide was a white tough polymer, and ηr = 3.20.

[Resin Production Example 2: Production of PA92C-2]
A mixture of 17.62 kg (111.3 mol) of 1,9-nonanediamine and 4.45 kg (28.1 mol) of 2-methyl-1,8-octanediamine (1,9-nonanediamine and 2-methyl-1,8 -Polyamide was obtained by carrying out the reaction in the same manner as in Production Example 1 except that the molar ratio of octanediamine was 80:20). The obtained polyamide was a white tough polymer and had ηr = 3.10.

[Resin Production Example 3: Production of PA92C-3]
A mixture of 11.11 kg (70.2 mol) of 1,9-nonanediamine and 11.11 kg (70.2 mol) of 2-methyl-1,8-octanediamine (1,9-nonanediamine and 2-methyl-1,8 -Polyamide was obtained by carrying out the reaction in the same manner as in Production Example 1 except that the molar ratio of octanediamine was 50:50). The obtained polymer was a white tough polymer, and ηr = 3.35.

[Resin Production Example 4: Production of PA92C-4]
1,9-nonanediamine 6.67 kg (42.1 mol), 2-methyl-1,8-octanediamine 15.56 kg (98.3 mol) in a mixture (1,9-nonanediamine and 2-methyl-1, A polyamide was obtained by reacting in the same manner as in Production Example 1 except that the molar ratio of 8-octanediamine was 30:70). The obtained polyamide was a white tough polymer, and ηr = 3.55.

[Resin Production Example 5: Production of PA92C-5]
A mixture of 1.33 kg (8.4 mol) of 1,9-nonanediamine and 20.88 kg (131.9 mol) of 2-methyl-1,8-octanediamine (1,9-nonanediamine and 2-methyl-1,8 -Polyamide was obtained by carrying out the reaction in the same manner as in Production Example 1 except that the molar ratio of octanediamine was 6:94). The obtained polymer was a white tough polymer, and ηr = 3.53.

[Resin Production Example 6: Production of PA92C-6]
A mixture of 1.33 kg (8.4 mol) of 1,9-nonanediamine and 20.88 kg (131.9 mol) of 2-methyl-1,8-octanediamine (1,9-nonanediamine and 2-methyl-1,8 -The octanediamine molar ratio was 6:94), and the reaction was carried out in the same manner as in Production Example 1 except that the internal pressure by extracting butanol was maintained at 0.25 MPa to obtain polyamide. The obtained polymer was a white tough polymer, and ηr = 4.00.

[Comparative Resin Production Example 1: Production of PA92]
Using only 22.25 kg (140.4 mol) of 1,9-nonanediamine as a diamine raw material, a reaction was carried out in the same manner as in Production Example 1 to obtain a polyamide. The obtained polymer was a yellowish white polymer, and ηr = 2.78.

  Polyamide resins PA92C-1 to PA92C-6, PA92 obtained in Resin Production Examples 1 to 6 and Comparative Resin Production Example 1, nylon 6 (Ube Industries, UBE nylon 1015B), nylon 66 (Ube Industries, UBE nylon) 2020B) and nylon 12 (Ube Industries, UBESTA3020U), relative viscosity, melting point, crystallization temperature, 1% weight loss temperature, melt viscosity, saturated water absorption, chemical resistance, hydrolysis resistance, dry and wet machinery Characteristics were measured. The results are shown in Table 1.

[Examples 1-6, Comparative Examples 1-2]
Using polyamides manufactured in Resin Production Example 1 and Comparative Resin Production Examples, and commercially available nylon 6 (UBE Nylon 1030B, manufactured by Ube Industries, Ltd.), nylon 12 (UBESTA 3035U), and mixtures of the components shown in Table 2, Table 2 A fuel tube having the layer structure shown in FIG. In Table 2, PA12 is nylon 12, benzenesulfonic acid butyramide is a plasticizer, and U-bond made by Ube Industries is maleic acid-modified polyethylene (U-bond F1100).

The low temperature impact property and fuel permeability of this fuel tube were evaluated. The surface of the tube after the fuel permeation test was visually observed to check for the presence of cracks, but no cracks were observed in any of the examples and comparative examples.
The evaluation results are shown in Table 2.

  The fuel tube of the present invention is excellent in fuel impermeability, fuel resistance, wide moldable temperature range, excellent melt moldability, low water absorption, chemical resistance, hydrolysis resistance, etc. It is useful as a fuel tube for automobiles.

Claims (6)

  The dicarboxylic acid component consists of oxalic acid, the diamine component consists of 1,9-nonanediamine and 2-methyl-1,8-octanediamine, and the molar ratio of 1,9-nonanediamine to 2-methyl-1,8-octanediamine A fuel tube comprising a layer of a polyamide resin having a ratio of 1:99 to 99: 1.   2. The relative viscosity (ηr) of the polyamide resin measured at 25 ° C. using a polyamide resin solution having a concentration of 1.0 g / dl using 96% sulfuric acid as a solvent is 1.8 to 6.0. Fuel tube.   The polyamide resin is obtained by differential scanning calorimetry measured at a 1% weight loss temperature in a thermogravimetric analysis measured at a heating rate of 10 ° C./min in a nitrogen atmosphere and at a heating rate of 10 ° C./min in a nitrogen atmosphere. The fuel tube according to claim 1 or 2, wherein a temperature difference from the measured melting point is 50 ° C or more.   The polyamide resin comprises a diamine component having a molar ratio of 1,9-nonanediamine and 2-methyl-1,8-octanediamine of 5:95 to 95: 5. The fuel tube as described.   The fuel tube according to any one of claims 1 to 4, wherein the polyamide resin layer includes a layered silicate.   The multilayer tube comprising the polyamide resin layer and a resin layer selected from a resin including a fluororesin, a high-density polyethylene resin, a polyamide 11 resin and / or a polyamide 12 resin containing a plasticizer. The fuel tube of any one of Claims.