JP2009298870A - Internal component of automobile engine room - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal component of an automobile engine room excellent in stiffness and heat resistance, achieving a sufficient high molecular weight formation, having a wide moldable temperature width estimated from the difference of its melting point and thermal decomposition temperature, excellent in melt moldability, further without damaging a low water absorption properties observed in an aliphatic linear polyoxamide resin, and as compared with conventional aliphatic polyamide resins, excellent in chemical resistance, hydrolysis resistance, etc. <P>SOLUTION: The internal component of the automobile engine room contains a fibrous reinforcing material with a polyamide resin of which the dicarboxylic acid component consists of oxalic acid, and the diamine component consists of 1,9-nonane diamine and 2-methyl-1,8-octane diamine, and having a (1:99) to (99:1) molar ratio of the 1,9-nonane diamine to the 2-methyl-1,8-octane diamine. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an automobile engine compartment interior part. More specifically, the present invention relates to a part in an automobile engine room that is excellent in low warpage and low water absorption, has a wide moldable temperature range, is excellent in molding processability, and is excellent in chemical resistance and hydrolysis resistance.

  Polyamide resin is widely used as a starting material for injection molding of automobile parts because of its excellent mechanical properties and ease of melt molding. For the purpose of high rigidity at the time, it has been proposed to reinforce the polyamide resin with glass fibers (Patent Document 1, etc.).

  However, when used as an engine room component, the polyamide resin has problems such as changes in physical properties due to water absorption, deterioration due to acid, high-temperature alcohol, fuel, hot water, and low warpage, heat resistance, Although it is desired that the chemical resistance (including anti-freezing agent) and the like be further improved, there are few attempts to improve the conventional polyamide resin itself.

  On the other hand, 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 2). It is expected to be used in fields where conventional polyamide is 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 (hereinafter abbreviated as PA92) in which the diamine component is 1,9-nonanediamine, 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. In addition, JP-A-5-506466 discloses 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 form 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) JP-A-2-240160 JP 2006-57033 A Japanese National Patent Publication No. 5-506466

  The problem to be solved by the present invention is low water absorption, suppresses changes in physical properties due to water absorption, deterioration in hot water, and the like, achieves a sufficiently high molecular weight, and is estimated from the difference between the melting point and the thermal decomposition temperature. The object of the present invention is to provide an automotive engine compartment component that has a wide moldable temperature range, excellent melt moldability, and excellent low warpage, heat resistance, chemical resistance, and hydrolysis resistance.

  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. In addition, according to the 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, the water absorption is low. Automotive engine room with high molecular weight, large difference between melting point and thermal decomposition temperature, excellent melt moldability, and low warpage, heat resistance, chemical resistance and hydrolysis resistance compared to conventional polyamide The present invention was completed by finding that internal parts can be obtained.

  The parts in the automobile engine compartment of the present invention have a low water absorption by using a novel polyamide resin, can suppress physical property changes due to water absorption, deterioration in hot water, etc., and can be made high molecular weight by melt polymerization. In addition, the moldable temperature range is as wide as 50 ° C. or more, the melt moldability is excellent, and the low warpage, heat resistance, chemical resistance, and hydrolysis resistance are also excellent. Further, by adding a fibrous reinforcing material, a layered silicate, etc. to the polyamide resin, mechanical properties, dimensional stability, heat resistance and the like can be further improved.

(1) Constituent components of polyamide resin Polyamide PA92C used in the automotive engine compartment part of the present invention has a dicarboxylic acid component composed of oxalic acid, and a diamine component composed 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 as described above, the moldable temperature range is wide, the melt moldability is excellent, and the low water absorption, chemical resistance, resistance A polyamide having excellent hydrolyzability can be obtained.

(2) Manufacture of polyamide resin The polyamide resin used for this invention can be manufactured using the arbitrary methods known as a method of manufacturing PA92C and 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 raw oxalic acid diester and diamine and that does not thermally decompose the polyoxamide produced by the polycondensation reaction of the oxalic acid diester and diamine. 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-resistant 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.

  It has also been found that the polyamide resin PA92C used in the present invention is superior in low warpage, heat resistance, and chemical resistance to calcium chloride used as an antifreezing agent as compared with conventional polyamide resins.

(4) Other components that can be blended in the polyamide resin Other polycarboxylic acid components can be mixed in the polyamide resin (PA92C) used for the components in the automobile engine room of the present invention 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 amount of the dicarboxylic acid component other than oxalic acid is preferably 5 mol% or less based on the total dicarboxylic acid component.

  The polyamide resin (PA92C) used in the present invention can be mixed with other diamine components as long as the effects of the present invention are not impaired. 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.

  The polyamide resin used in the present invention can be partially substituted 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. . Furthermore, you may substitute with thermoplastic polymers other than polyamide, and an elastomer. When the polyamide resin PA92C is substituted with another resin, the substitution amount with the other resin is preferably 50% by mass or less.

  In the automobile engine compartment component of the present invention, preferably, the polyamide resin further includes a fibrous reinforcing material, so that mechanical characteristics (particularly rigidity), heat resistance, and the like can be improved.

  Examples of fibrous reinforcing materials include fibrous inorganic fillers such as glass fibers, carbon fibers, and wollastonite, and ceramic whiskers such as silicon nitride and potassium titanate.

  The shape of the fiber is not particularly limited. For example, in the case of glass fiber and carbon fiber, the fiber diameter is preferably 2 to 20 μm, more preferably 4 to 15 μm. Moreover, the aspect ratio (fiber length / fiber diameter) is preferably 4 to 70 in the molded body, and more preferably 5 to 50. If the fiber diameter is too small, it is difficult to produce. If the fiber diameter is too large, the mechanical properties, particularly impact resistance, of the molded article may be reduced. Further, if the aspect ratio is small, the reinforcing effect is low, and if it is too large, warpage during molding increases, which is not preferable.

  Wollastonite preferably has an aspect ratio of 3 to 70, and silicon nitride and potassium titanate preferably have a fiber diameter of 0.1 to 3 μm.

  The blending amount of the fibrous reinforcing material is preferably 150 parts by mass or less, and more preferably 100 parts by mass or less with respect to 100 parts by mass of the polyamide resin. When the amount is too large, the fluidity of the composition is lowered, and the surface of the molded product is difficult to be smooth or warpage is likely to occur. The lower limit of the amount of the fibrous reinforcing material is not limited, but in order to obtain excellent mechanical properties and thermal properties by blending the fibrous reinforcing material, it is preferably 3 parts by mass or more, more preferably 20 parts by mass or more. .

  Further, the polyamide resin composition for automotive engine compartment parts of the present invention can preferably contain a layered silicate. By including the layered silicate, excellent rigidity and dimensional stability can be imparted to the automotive engine room component material.

  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, for example, smectite clay minerals such as montmorillonite, sabonite, beidellite, nontronite, hectorite, and stevensite, vermiculite, and halosite. These may be natural products or synthetic products.

  When dispersed in the composition, the layered silicate maintains 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.

  30 mass parts or less are preferable with respect to 100 mass parts of resin, as for the compounding quantity of layered silicate, 0.05-10 mass parts is more preferable, and 0.05-5 mass parts is further more preferable. When the amount exceeds 30 parts by mass, molding may become difficult, and impact strength and flexibility may be reduced. If it is less than 0.05 parts by mass, sufficient effects may not be obtained.

  Furthermore, the polyamide resin composition obtained according to the present invention may include other fillers, reinforcing materials, heat-resistant materials, stabilizers such as copper compounds, colorants, ultraviolet absorbers, light stabilizers, and antioxidants as necessary. An agent, 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.

(6) Kneading and Molding of Polyamide Resin and Composition The method for producing parts in an automobile engine room from the polyamide resin or resin composition in the present invention is not limited to a specific method, but as a specific and efficient example, a raw material A method of supplying a kneaded polyamide resin or a mixture thereof with other raw materials to a generally known melt mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, a mixin gall, etc. As an example. In addition, there is no particular limitation on the mixing order of the raw materials, a method in which all the raw materials are blended and then melt-kneaded by the above method, a part of the raw materials are blended and then melt-kneaded by the above method, and the remaining raw materials are blended and melted Any method may be used, such as a method of kneading or a method of mixing a part of raw materials and mixing the remaining raw materials using a side feeder during melt-kneading with a single or twin screw extruder.

  Moreover, there is no restriction | limiting in particular about the method of shape | molding the components in an automobile engine room from a polyamide resin or a resin composition, A polyamide resin composition is injection-molded using an injection molding machine, or it presses using a press molding machine. Can be molded.

(7) Automotive engine compartment components The automotive engine compartment components of the present invention include intake manifolds, air cleaners, resonators, fuel rails, throttle bodies and valves, air flow meters, EGR components, harness connectors, engine covers, cylinder head covers, Timing belt (chain cover), timing chain (belt) tensioner and guide, alternator cover, distributor cover, brake master cylinder, oil pump, oil filter, engine mount, paper canister, power steering oil reservoir, fuel strainer, radiator tank , Switch boots, lamp waterproof cover, connector cover, rubber hook, suspension There are boots, suspension upper mounts, suspension bushings, stabilizer bushings, steering rack boots, steering rack bushings, reservoir tank caps, plug cord caps, molded packing, battery terminal covers, etc.

[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 cone plate to a melt viscoelasticity measuring device ARES manufactured by TA Instruments Japan, under conditions of 250 ° C. and shear rate of 0.1 s ⁻¹ in nitrogen. It was measured.

(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 3 times within a range of 0.2% or less, it is determined 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. ) Is shown in the table as the water absorption rate (equilibrium water absorption rate) in wet conditions.

(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. Tests were conducted on samples immersed in concentrated hydrochloric acid, 64% sulfuric acid, 30% aqueous sodium hydroxide and 5% aqueous potassium permanganate at 23 ° C., and for benzyl alcohol at 50 ° C.

(8) Hydrolysis resistance After the polyamide hot press film obtained by the present invention was put in an autoclave and treated in water, 0.5 mol / l sulfuric acid and 1 mol / l sodium hydroxide aqueous solution at 121 ° C. for 60 minutes, respectively. The weight residual ratio (%) and the appearance change 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.

  [1] Tensile test (tensile yield point strength and tensile elongation at break): Measured in accordance with ASTM D638 using a Type I test piece described in ASTM D638.

  [2] Bending test (bending strength and flexural modulus): Measured at 23 ° C. in accordance with ASTM D790 using a test piece having a test piece size of 127 mm × 12.7 mm × 3.2 mm.

  [3] Impact strength (with Izod notch): Measured at 23 ° C. in accordance with ASTM D256 using a test piece having a test piece size 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) Warpage measurement test Using an injection molding machine (Toshiba Machine N140II), cylinder set temperature: C ₁ 240 ° C .; C ₂ 270 ° C .; C ₃ 270 ° C .; C ₄ 270 ° C., nozzle heater 270 ° C., injection Pressure: primary pressure 60 MPa, mold temperature: moving mold 80 ° C .; fixed mold 80 ° C., injection time: 13 seconds, cooling time: 20 seconds. And the degree of warpage was measured. The warpage was determined from the following equation by measuring the dimensions A and B in FIG.
Warpage (inner deflection) = [(B length−A length) / B length] × 100

(11) Thermal deformation temperature (heat resistance)
Measurement was performed under the condition of a load of 1.82 MPa in accordance with ASTM D648 using a test piece having a test piece size of 6.35 mm × 12.7 mm × 127 mm.

(12) Calcium chloride resistance:
An ASTM No. 1 test piece was used and immersed in water at 80 ° C. for 8 hours as a pretreatment. Next, after conditioning for 1 hour in a constant temperature and humidity chamber at 80 ° C. and 85% RH, a saturated calcium chloride aqueous solution was applied to the test piece and heat-treated in an oven at 100 ° C. for 1 hour. This humidity control treatment and heat treatment were taken as one cycle, repeated up to 30 cycles, and the number of cycles in which the test piece cracked was used as an index.

[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.

  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), nylon 66 (Ube Industries, UBE nylon 2020B) and nylon 12 ( For Ube Industries, UBESTA3020U), the 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.

  Furthermore, about the polyamide of Examples 1-5, and nylon 6 (UBE Kosan UBE nylon 1015B; PA6), curvature, heat-deformation temperature, and calcium chloride resistance were measured. The results are shown in Table 2.

[Examples 7 to 8, Comparative Example 5]
Each of the polyamide resin of Example 1 and Example 5 and commercially available nylon 6 (UBE nylon 1015B manufactured by Ube Industries) was kneaded in a 44 mmφ vented twin screw extruder set at a barrel temperature of 285 ° C. When kneading into this polyamide resin, glass fiber (average diameter 11 μm, average fiber length 3 mm) is supplied from the middle of the extruder so as to be 43 parts by mass with respect to 100 parts by mass of the polyamide resin. Composition pellets were prepared (Examples 7-8 and Comparative Example 5).

These pellets were dried at 110 ° C. under a reduced pressure of 10 Torr for 24 hours, then injection molded at a cylinder temperature of 285 ° C. and a mold temperature of 80 ° C. to prepare various test pieces, warping, bending elastic modulus (dry and wet), The heat distortion temperature, equilibrium water absorption, and calcium chloride resistance were measured.
The results are shown in Table 2. In Table 2, the flexural modulus (dry and wet), heat distortion temperature, and equilibrium water absorption shown in Table 1 are also shown for comparison.

  The polyamide resin composition which is a material for automobile engine compartment parts according to the present invention has low water absorption, high molecular weight, wide moldable temperature range, excellent melt moldability, and low warpage, heat resistance, chemical resistance It is also excellent in water resistance and hydrolysis resistance, so it can be widely used in the production of automobile engine compartment parts.

It is a figure explaining the measuring method of curvature.

Claims (5)

  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 component in an automobile engine room, characterized by comprising 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. Car engine room parts.   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 automotive engine compartment component according to claim 1 or 2, wherein a temperature difference from the measured melting point is 60 ° 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. Parts in the car engine compartment as described.   The automotive engine compartment component according to any one of claims 1 to 4, wherein the polyamide resin includes a fibrous reinforcing material.

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