JP5572921B2 - Molded parts in direct contact with biodiesel fuel - Google Patents

Description

  The present invention relates to a molded member in direct contact with biodiesel fuel. Specifically, it is excellent in biodiesel fuel resistance, has low water absorption and hydrolysis resistance, has a wide moldable temperature range, and is in direct contact with biodiesel fuel using a new polyamide resin with excellent moldability. The present invention relates to a molded member.

  Crystalline polyamides typified by nylon 6 and nylon 66 are widely used as clothing, industrial material fibers, or general-purpose engineering plastics because of their excellent characteristics and ease of melt molding. 11. Nylon 12 has basic performances required for fuel parts with oil resistance and fuel permeation prevention, so fuel tanks, fuel pipes, fuel transfer units, fuel pump modules, valves for gasoline and light oil fuels It is used for molded members that come into contact with fuel.

  In recent years, in order to reduce carbon dioxide emissions, it has been studied to use biodiesel fuel instead of gasoline fuel. Biodiesel fuel is a fuel composed of vegetable oils such as rapeseed oil, sunflower oil, soybean oil and corn oil, and fatty acid methyl esters obtained by esterifying these waste edible oils with crude oil and methanol to separate and remove glycerin. In general, biodiesel fuel is used by mixing this fatty acid methyl ester in a proportion of light oil.

  However, it is considered that the resistance of polyamide resin to biodiesel fuel is different from the resistance of gasoline and light oil to conventional fuel, and those having conventional fuel resistance are not necessarily excellent in resistance to biodiesel fuel. Therefore, there is a demand for fuel parts made of polyamide resin having excellent resistance to the biodiesel fuel of polyamide resin.

  In addition to the fuel resistance, polyamide resins used in fuel parts also have problems such as changes in physical properties due to water absorption, deterioration in acid and high-temperature alcohol, and so on. There is a request.

  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 Document 1). It is expected to be used in fields where the use of conventional polyamides, where changes in physical properties have become a problem, is difficult.

  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. It is also 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 2). 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.
SW Shalaby., J. Polym. Sci., 11, 1 (1973) L. Franco et al., Macromolecules., 31, 3912 (1988) JP 2006-57033 A Japanese National Patent Publication No. 5-506466

  The problems to be solved by the present invention are excellent in biodiesel fuel resistance, low water absorption, excellent hydrolysis resistance, wide moldable temperature range, and direct contact with biodiesel fuel excellent in moldability. An object of the present invention is to provide a molded polyamide resin member.

  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 polyamide resin (PA92C) using a mixture in which the molar ratio of 1,9-nonanediamine and 2-methyl-1,8-octanediamine is 1:99 to 99: 1 is excellent in biodiesel-resistant fuel, and It is a polyamide resin that is excellent in hydrolysis resistance without impairing the low water absorption seen in linear polyoxamide resin, and has a high molecular weight, a large difference in melting point and thermal decomposition temperature, and excellent melt moldability. Therefore, it has been found that if this polyamide resin is used, a polyamide resin molded member that is in direct contact with the target biodiesel fuel is provided. Completed.

  According to the present invention, polyamide resin molding is excellent in biodiesel fuel resistance, low water absorption, hydrolysis resistance, wide moldable temperature range, and direct contact with biodiesel fuel excellent in molding processability. A member is provided.

(1) Constituent Component of Polyamide Resin Polyamide PA92C used in the present invention has a dicarboxylic acid component composed of oxalic acid, a diamine component composed of 1,9-nonanediamine and 2-methyl-1,8-octanediamine, It is a polyamide resin which is a diamine mixture in which the molar ratio of 9-nonanediamine and 2-methyl-1,8-octanediamine is 1:99 to 99: 1.

  As the oxalic acid source used for the production of this 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 acids of aromatic alcohols such as diphenyl oxalate Examples include diesters.

  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 amounts, it is excellent in biodiesel fuel resistance, low water absorption, hydrolysis resistance, and moldable temperature. A polyamide having a wide width and excellent melt moldability can be obtained.

(2) Manufacture of polyamide resin Polyamide resin PA92C used by this invention can be manufactured using the arbitrary methods known as a method of manufacturing 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 does not decompose. 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 Physical Properties of Polyamide Resin There is no particular restriction on the molecular weight of the polyamide resin PA92C used in the present invention, but a 96% concentrated sulfuric acid solution having a polyamide resin concentration of 1.0 g / dl using 96% concentrated sulfuric acid as a solvent. 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 in 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, whereby oxalic acid and 1,9-nonanediamine are copolymerized. It is possible to increase the relative viscosity, that is, increase the molecular weight as compared with the polyamide. 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.

  Furthermore, the present invention has been completed after confirming that the polyamide resin PA92C is excellent in biodiesel fuel properties. Biodiesel fuel is a fuel composed of vegetable oils such as rapeseed oil, sunflower oil, soybean oil and corn oil, and fatty acid methyl esters obtained by esterifying these waste edible oils with crude oil and methanol to separate and remove glycerin.

(4) Components that can be blended in the polyamide resin of the present invention The polyamide resin PA92C used in the present invention can be mixed with other dicarboxylic acid components within a range not impairing the effects of the present invention. 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 compounding quantity of other dicarboxylic acid components other than oxalic acid is 5 mol% or less based on the total dicarboxylic acid component.

  Moreover, other diamine components can be mixed in the polyamide resin PA92C used in 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 5 mol% or less based on the total diamine component.

  In the molded part excellent in biodiesel fuel resistance of the present invention, a part of the above polyamide resin may be used as a part of other polyoxamides, aromatic polyamides, aliphatic polyamides, and alicyclic polyamides as long as the effects of the present invention are not impaired. It is possible to substitute with polyamides. Further, a thermoplastic polymer other than polyamide or an elastomer can be substituted. However, the resin to be replaced other than the polyamide resin PA92C is preferably 50% by mass or less.

  In particular, a layered silicate can be added to the molded part excellent in biodiesel fuel resistance of the present invention for the purpose of reducing biodiesel fuel permeability.

  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 mass part-10 mass parts are preferable with respect to 100 mass parts of polyamide resins, and, as for the compounding quantity of layered silicate, 0.05 mass part-5 mass parts are 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.

It is preferable that a plasticizer is further added to the molded part excellent in biodiesel fuel resistance of the present invention. Examples of the plasticizer include benzenesulfonic acid butyramide, esters of p-hydroxybenzoic acid and linear or branched alcohols having 6 to 21 carbon atoms (for example, 2-ethylhexyl p-hydroxybenzoate) and the like. 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 it exceeds 30 parts by mass, there is a possibility of bleeding out.

  Furthermore, in the molded part excellent in biodiesel fuel resistance of the present invention, if necessary, a reinforcing material such as glass fiber, a filler, a stabilizer such as a copper compound, a colorant, an ultraviolet absorber, and a light stabilizer. Further, an antioxidant, an antistatic agent, a flame retardant, a crystallization accelerator, a conductive material, a lubricant and the like can be added during or after the polycondensation reaction.

(5) Molding process of molded part As a molding method of the molded part excellent in biodiesel fuel resistance of the present invention, a polyamide resin or a polyamide resin composition blended with various blending components and additives is injected, extruded, and hollow. Any known molding process that can be applied to polyamide, such as press, roll, foaming, vacuum / compressed air, or stretching, is possible, and by these molding processes, films, sheets, molded articles, fibers, and the like can be processed.

(6) Use of molded parts excellent in biodiesel fuel resistance The molded parts excellent in biodiesel fuel resistance obtained by the present invention are used for any of various molded parts in which conventional polyamide resin fuel parts have been used. It is possible. Examples of the molded member that comes into contact with the biodiesel fuel include a fuel tank, a fuel tube, a fuel pipe, a fuel transfer unit, a fuel pump module, and a valve.

[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 lasts three times in the range of 0.2%, it is determined that the absorption of water into the polyamide resin film has reached saturation, and the film weight (Xg) before dipping in water The saturated water absorption (%) was calculated from the weight (Yg) of the film when the saturation was reached 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) Biodiesel fuel resistance Using the biodiesel fuel manufactured by AKM Co., Ltd., the test piece of (9) was immersed at 140 ° C. for 100 hours. The total amount of fatty acid methyl ester of the biodiesel fuel used was 90.2 wt%, the density (15 ° C.) was 0.8864 g / mL, and the acid value was 0.09 mg KOH / g. The crack generation state on the surface of the test piece taken out after 100 hours was visually observed. Further, the tensile strength and tensile elongation retention rate of the test piece before the fuel immersion test and after 100 hours of fuel immersion were evaluated. Tensile strength (elongation) retention rate (%) = [tensile strength (elongation) after 100 hours of fuel immersion] / [tensile strength (elongation) before immersion in fuel] × 100.

[Example 1: 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.

[Example 2: 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 A polyamide was obtained by reacting in the same manner as in Example 1 except that the octanediamine molar ratio was 80:20). The obtained polyamide was a white tough polymer and had ηr = 3.10.

[Example 3: 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 reacting in the same manner as in Example 1 except that the octanediamine molar ratio was 50:50). The obtained polymer was a white tough polymer, and ηr = 3.35.

[Example 4: 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 carrying out the reaction in the same manner as in 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.

[Example 5: 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 Example 1 except that the molar ratio of octanediamine was 6:94). The obtained polymer was a white tough polymer, and ηr = 3.53.

[Example 6: 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 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 Example 1: 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 Example 1 to obtain a polyamide. The obtained polymer was a yellowish white polymer, and ηr = 2.78.

[Comparative Examples 2 to 4]
Comparative Examples 2 to 4 are commercially available nylon 6 (Ube Industries, UBE nylon 1015B), nylon 66 (Ube Industries, UBE nylon 2020B) and nylon 12 (Ube Industries, UBESTA 3020U).

  Polyamide resins PA92C-1 to PA92C-6 and PA92 of Examples 1 to 6 and Comparative Example 1, and nylon 6 (Ube Industries, UBE nylon 1015B) of Comparative Examples 2 to 4, nylon 66 (Ube Industries, UBE) Nylon 2020B) and nylon 12 (manufactured by Ube Industries, UBESTA3020U) in relative viscosity, melting point, crystallization temperature, 1% weight loss temperature, melt viscosity, saturated water absorption, chemical resistance, hydrolysis resistance, dry and wet Mechanical properties were measured. The results are shown in Table 1.

For the polyamide resins PA92C-1 to PA92C-6 of Examples 1 to 5, and nylon 66 (Ube Industries, UBE nylon 2020B) and nylon 12 (Ube Industries, UBESTA3020U) of Comparative Examples 3 to 4, biodiesel resistance The fuel property was evaluated. The results are shown in Table 2.

  The molded part according to the present invention is excellent in biodiesel fuel resistance, low water absorption, molding processability, and the like, and thus is expected to be greatly used for parts that are in direct contact with biodiesel fuel.

Claims (3)

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 molded member in direct contact with biodiesel fuel, characterized in that it comprises a polyamide resin having a ratio of 5:95 to 95: 5 .   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. Molded parts in direct contact with biodiesel fuel.   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 molded member in direct contact with the biodiesel fuel according to claim 1, wherein a temperature difference from the measured melting point is 50 ° C. or more.