Semi-aromatic polyamide

Abstract

To provide a semi-aromatic polyamide with a narrow molecular weight distribution. 【Solution means】The semi-aromatic polyamide of the present invention comprises a constituent component derived from an aromatic dicarboxylic acid (A), a constituent component derived from an aliphatic diamine (B), and the following formula (c) H2N-R 1 -NH-R 2 (c) (In the formula, R 1 represents an alkylene group, and R 2 represents an alkyl group) and a constituent component derived from an aliphatic monoamine (C) represented by, and The content of the constituent component derived from the aliphatic monoamine (C), determined by gas chromatography analysis, is 0.01 to 3.0% of the content of the constituent component derived from the aliphatic diamine (B).

Description

[Technical Field]

[0001] The present invention relates to a semi-aromatic polyamide with a narrow molecular weight dispersion, a resin composition containing the semi-aromatic polyamide, a molded article of the resin composition, and a method for producing the semi-aromatic polyamide. [Background technology]

[0002] Semi-aromatic polyamides are widely used as molding resins for electrical and electronic components, automotive parts, and other applications due to their high heat resistance, low water absorption, and excellent mechanical properties.

[0003] Patent Document 1 discloses that a powdery mixture containing a salt and a low polymer can be obtained by sequentially adding a diamine to a mixture containing a dicarboxylic acid powder and a monocarboxylic acid as a chelating agent and reacting the mixture, and then increasing the molecular weight of the obtained mixture by solid-phase polymerization or melt polymerization, thereby enabling the efficient production of high molecular weight semi-aromatic polyamides.

[0004] However, a problem arose when the addition of diamines began: the presence of monocarboxylic acid, a terminal chelating agent, made it easy for low molecular weight polymers to form.

[0005] Therefore, as a method to solve the above problem, Patent Document 2 discloses that the formation of low molecular weight polymers is suppressed by continuously adding diamine to dicarboxylic acid powder, and then adding monocarboxylic acid, which is a terminal chelating agent, after more than half of the diamine has been added.

[0006] Furthermore, Patent Document 3 discloses that a semi-aromatic polyamide with high molecular weight and excellent hydrolysis resistance can be obtained by reacting a dicarboxylic acid, a diamine, and a monocarboxylic acid, which is a chelating agent, with water at a specific reaction rate to produce a primary polycondensate, and then dehydrating the obtained primary polycondensate and performing solid-phase polymerization. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 2012 / 070457 [Patent Document 2] Japanese Patent Publication No. 2014-177582 [Patent Document 3] Japanese Patent Publication No. 2000-103847 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, the manufacturing method described in the above-mentioned patent document still lacked sufficient control over molecular weight. As a result, the resulting semi-aromatic polyamide had a wide molecular weight dispersion, which was problematic because it had poor performance in terms of waterproofing, moldability, and mechanical properties (e.g., vibration fatigue properties and creep properties).

[0009] Therefore, the object of the present invention is to provide a semi-aromatic polyamide with a narrow molecular weight dispersion. Another object of the present invention is to provide a resin composition that contains the semi-aromatic polyamide and can form molded articles with excellent waterproofing properties. Another object of the present invention is to provide a molded article of the resin composition. Another object of the present invention is to provide a method for producing semi-aromatic polyamides with a narrow molecular weight dispersion. [Means for solving the problem]

[0010] As a result of intensive studies to solve the above problems, the present inventors found that when an aromatic dicarboxylic acid (A), an aliphatic diamine (B), and an aliphatic monoamine (C) represented by the following formula (c) in a specific amount with respect to the aliphatic diamine (B) are reacted to form a polymer precursor, and the resulting polymer precursor is subjected to dehydration condensation, the dehydration condensation reaction proceeds at an appropriate rate, so that a semi-aromatic polyamide with a narrow molecular weight distribution can be obtained. When the semi-aromatic polyamide thus obtained is solidified, a solid product excellent in waterproofness, mechanical properties, etc. can be obtained. The present invention has been completed based on these findings.

[0011] That is, the present invention provides a semi-aromatic polyamide containing a constituent component derived from an aromatic dicarboxylic acid (A), a constituent component derived from an aliphatic diamine (B), and a constituent component derived from an aliphatic monoamine (C) represented by the following formula (c): H2N-R-NH-R 2 (c) (In the formula, R 1 represents an alkylene group, and R 2 represents an alkyl group) and having a content of the constituent component derived from the aliphatic monoamine (C) of 0.01 to 3.0% of the content of the constituent component derived from the aliphatic diamine (B) as determined by gas chromatography analysis. The present invention also provides the above semi-aromatic polyamide having a molecular weight distribution Mw / Mn of 3.0 or less.

[0012] The present invention also provides the above semi-aromatic polyamide further containing a constituent component derived from a monocarboxylic acid (D)

[0013] and having a content of the constituent component derived from the monocarboxylic acid (D) of 0.01 to 8.0 mol% of the content of the constituent component derived from the aromatic dicarboxylic acid (A). The present invention also provides the above semi-aromatic polyamide in which the aromatic dicarboxylic acid component (A) contains terephthalic acid.

[0014] The present invention also provides the above semi-aromatic polyamide.

[0015] ​The present invention also relates to a case where the aliphatic diamine component (B) is represented by the following formula (b) H2N-R 1 ’-NH2(b) (In the formula, R 1 ’ represents an alkylene group having 6 or more carbon atoms) and contains a compound represented by where the aliphatic monoamine (C) is represented by the following formula (c1) H2N-R 1 ’-NH-R 2 ’ (c1) (In the formula, R 1 ’ is the same as defined above, and R 2 ’ represents an alkyl group having 1 to 3 carbon atoms) and provides the above semi-aromatic polyamide containing a compound represented by

[0016] The present invention also provides a resin composition containing the above semi-aromatic polyamide

[0017] The present invention also provides a molded article of the above resin composition

[0018] The present invention also relates to a method for producing a semi-aromatic polyamide for obtaining the above semi-aromatic polyamide, which includes the following step 1 and step 2, and in the following step 1, the content of the aliphatic monoamine (C) is set to 0.01 to 3.0% of the content of the aliphatic diamine (B), so that the maximum value of the discharge rate of the condensed water with respect to the total amount of the carboxylic acid component and the amine component charged by the dehydration condensation in the following step 2 is 25 g / kg·min or less, and provides a method for producing a semi-aromatic polyamide Step 1: A step of reacting a carboxylic acid component containing an aromatic dicarboxylic acid (A), an aliphatic diamine (B), and an aliphatic monoamine (C) represented by the following formula (c) H2N-R 1 -NH-R 2 (c) (In the formula, R 1 represents an alkylene group, and R 2 represents an alkyl group) to produce a polymer precursor Step 2: A step of subjecting the produced polymer precursor to dehydration condensation [Effects of the Invention]

[0019] The semi-aromatic polyamide of the present invention contains components derived from aromatic dicarboxylic acid (A), aliphatic diamine (B), and aliphatic monoamine (C) in specific proportions. Therefore, it has a narrow molecular weight dispersion, and when subjected to molding treatment, it can form molded articles with excellent water resistance and mechanical properties. Accordingly, the semi-aromatic polyamide of the present invention can be suitably used as a resin for molding articles for a wide range of applications such as automotive parts, electrical and electronic components, sliding parts, general merchandise, industrial equipment parts, and civil engineering and construction materials. [Modes for carrying out the invention]

[0020] [Semi-aromatic polyamide] Polyamides contain components derived from carboxylic acids and components derived from amines. The semi-aromatic polyamide of the present invention contains a component derived from an aromatic dicarboxylic acid (A) as a carboxylic acid-derived component. It also contains a component derived from an aliphatic diamine (B) and a component derived from an aliphatic monoamine (C) as amine-derived components.

[0021] The carboxylic acid that forms the component derived from the carboxylic acid includes at least one aromatic dicarboxylic acid (A).

[0022] Aromatic dicarboxylic acid (A) is a compound composed of an aromatic ring and two carboxyl groups bonded to the aromatic ring. The aromatic ring may be an aromatic hydrocarbon ring having 6 to 10 carbon atoms, such as a benzene ring or a naphthalene ring. In addition, substituents other than carboxyl groups may be bonded to the aromatic ring. Examples of such substituents include C 1-5 Alkyl alkyl group, C 1-5 Alkoxy group, C 1-5 Examples include acyloxy groups. Aromatic dicarboxylic acid (A) may contain one of the above compounds alone, or two or more of the above compounds in combination.

[0023] Examples of aromatic dicarboxylic acids (A) include terephthalic acid, phthalic acid, isophthalic acid, and naphthalenedicarboxylic acid. Among these, it is preferable that the aromatic dicarboxylic acid (A) contains at least terephthalic acid, as this allows for the production of a semi-aromatic polyamide with a high melting point, low water absorption, and high crystalline properties. The terephthalic acid content is preferably 60 mol% or more of the total aromatic dicarboxylic acid (A), more preferably 80 mol% or more, even more preferably 90 mol% or more, particularly preferably 95 mol% or more, and most preferably 97 mol% or more.

[0024] The semi-aromatic polyamide of the present invention may further contain a component derived from a monocarboxylic acid (D) as a carboxylic acid-derived component, and the carboxylic acid forming the carboxylic acid-derived component may include monocarboxylic acid (D) in addition to aromatic dicarboxylic acid (A).

[0025] Monocarboxylic acid (D) includes aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids. Monocarboxylic acid (D) may contain one of the above compounds alone, or two or more of the above compounds in combination.

[0026] Examples of aliphatic monocarboxylic acids include acetic acid, butyric acid, caproic acid, caprylic acid, nonanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid. Among these, stearic acid is preferred due to its high versatility.

[0027] Examples of alicyclic monocarboxylic acids include cyclohexanecarboxylic acid, 4-methylcyclohexanecarboxylic acid, 4-ethylcyclohexanecarboxylic acid, 4-hexylcyclohexanecarboxylic acid, and 4-laurylcyclohexanecarboxylic acid.

[0028] Examples of aromatic monocarboxylic acids include benzoic acid, 4-methylbenzoic acid, 4-ethylbenzoic acid, 4-hexylbenzoic acid, 4-laurylbenzoic acid, alkylbenzoic acids, 1-naphthoic acid, and 2-naphthoic acid.

[0029] The monocarboxylic acid (D) preferably contains at least one compound selected from aliphatic monocarboxylic acids such as stearic acid and aromatic monocarboxylic acids such as benzoic acid, and it is particularly preferable to contain at least an aliphatic monocarboxylic acid such as stearic acid from the viewpoint of improving water resistance and narrowing the degree of molecular weight dispersion.

[0030] In the total amount of monocarboxylic acid (D), the proportion of aliphatic monocarboxylic acids such as stearic acid is, for example, 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more.

[0031] The content of monocarboxylic acid (D)-derived components in the semi-aromatic polyamide of the present invention is preferably 0.01 to 8.0 mol% of the content of aromatic dicarboxylic acid (A)-derived components, from the viewpoint of suppressing an excessively fast reaction rate in the dehydration condensation reaction and reducing molecular weight dispersion. Furthermore, the content of monocarboxylic acid (D)-derived components relative to the content of aromatic dicarboxylic acid (A)-derived components is preferably 0.1 to 7.0 mol%, more preferably 0.3 to 6.0 mol%, and even more preferably 0.5 to 4.0 mol%, from the viewpoint of balancing mechanical properties and melt viscosity. When the content of monocarboxylic acid (D)-derived components is 0.01 mol% or more, the content of monocarboxylic acid (D)-derived components relative to the content of aromatic dicarboxylic acid (A)-derived components of the semi-aromatic polyamide is 1 It can be determined by 1H-NMR measurement (solvent: deuterated trifluoroacetic acid, temperature: 25°C).

[0032] The semi-aromatic polyamide of the present invention may contain, in addition to the aromatic dicarboxylic acid (A) component, other components derived from aliphatic dicarboxylic acids or alicyclic dicarboxylic acids as carboxylic acid-derived components. That is, the carboxylic acids that form the carboxylic acid-derived components may further include aliphatic dicarboxylic acids or alicyclic dicarboxylic acids.

[0033] Aliphatic dicarboxylic acids are compounds composed of an aliphatic hydrocarbon chain and two carboxyl groups bonded to the hydrocarbon chain. Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanediic acid, and dodecanediic acid.

[0034] Alicyclic dicarboxylic acids are compounds composed of an alicyclic hydrocarbon skeleton (a skeleton consisting of hydrocarbons containing an alicyclic ring) and two carboxyl groups bonded to the skeleton. Examples of aliphatic dicarboxylic acids include cyclohexanedicarboxylic acid.

[0035] When the semi-aromatic polyamide of the present invention contains components derived from aromatic dicarboxylic acid component (A) along with components derived from other dicarboxylic acids (e.g., aliphatic dicarboxylic acids or alicyclic dicarboxylic acids), the content of components derived from dicarboxylic acids other than aromatic dicarboxylic acid component (A) (total content if two or more are included) is preferably 20 mol% or less, and more preferably 10 mol% or less, relative to the total number of moles of raw material monomers of the semi-aromatic polyamide. Furthermore, the content of dicarboxylic acids other than aromatic dicarboxylic acid component (A) (total content if two or more are included) is preferably 20 mol% or less, more preferably 10 mol% or less, particularly preferably 5 mol% or less, most preferably 1 mol% or less, and especially preferably substantially absent, relative to the total amount of carboxylic acid-derived components.

[0036] The amines that form the amine-derived components include aliphatic diamines (B) and aliphatic monoamines (C). Aliphatic diamines (B) and aliphatic monoamines (C) may be included individually or in combination of two or more of the aforementioned compounds.

[0037] Aliphatic diamines (B) are compounds composed of an aliphatic hydrocarbon skeleton (for example, a linear or branched alkylene group) and two amino groups bonded to the skeleton.

[0038] The aliphatic hydrocarbon skeleton is, for example, a linear or branched alkylene group, and the number of carbon atoms is, for example, 1 or more, preferably 6 or more, and more preferably 9 or more. Furthermore, the number of carbon atoms is preferably 16 or less, and more preferably 12 or less.

[0039] Examples of aliphatic diamines (B) include 1,2-ethanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 2-methyl-1,5-pentanediamine, and 2-methyl-1,8-octanediamine.

[0040] Among the aliphatic diamine components (B), the compound represented by the following formula (b) is preferred because it allows for the production of a semi-aromatic polyamide that is highly crystalline and has excellent heat resistance, water resistance, and chemical resistance. H2N-R 1 -NH2(b) (In the formula, R 1 ' indicates an alkylene group with 6 or more carbon atoms.

[0041] The aliphatic diamine (B) is preferably 1,10-decanediamine, and the proportion of 1,10-decanediamine in the total amount of aliphatic diamine (B) is, for example, 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more.

[0042] Aliphatic monoamines (C) are compounds represented by the following formula (c). H2N-R 1 -NH-R 2 (c) (In the formula, R 1 R indicates an alkylene group, 2 (This indicates an alkyl group.)

[0043] R 1 The number of carbon atoms in the alkylene group is 1 or more. In particular, in order to obtain a semi-aromatic polyamide that is highly crystalline and has excellent heat resistance, water resistance, and chemical resistance, the number of carbon atoms in the alkylene group is preferably 6 or more, more preferably 8 or more, particularly preferably 9 or more, and most preferably 10 or more. Furthermore, the number of carbon atoms is preferably 16 or less, more preferably 12 or less.

[0044] R 1 Examples of alkylene groups in this context include linear or branched alkylene groups such as methylene group, methylmethylene group, dimethylmethylene group, ethylene group, propylene group, trimethylene group, tetramethylene group, hexamethylene group, nonamethylene group, decamethylene group, undecamethylene group, and dodecamethylene group.

[0045] R 2 Examples of alkyl groups in this context include C1-C16 alkyl groups such as methyl, ethyl, propyl, butyl, octyl, and decyl groups. Among these, C1-C3 alkyl groups are preferred, C1 or C2 alkyl groups are more preferred, and methyl groups are particularly preferred.

[0046] Examples of aliphatic monoamines (C) include N-methyl-1,6-hexanediamine, N-methyl-1,9-nonanediamine, N-methyl-1,10-decanediamine, N-ethyl-1,6-hexanediamine, N-ethyl-1,9-nonanediamine, N-ethyl-1,10-decanediamine, N-propyl-1,6-hexanediamine, N-propyl-1,9-nonanediamine, and N-propyl-1,10-decanediamine.

[0047] Among the aliphatic monoamines (C), compounds represented by the following formula (c1) are preferred because they are highly crystalline and can yield semi-aromatic polyamides with excellent heat resistance, water resistance, and chemical resistance. H2N-R 1 '-NH-R 2 (c1) (In the formula, R 1 ' indicates an alkylene group with 6 or more carbon atoms, R 2 (' indicates an alkyl group with 1 to 3 carbon atoms)

[0048] As for aliphatic monoamines (C), in particular, NC 1-3 It is preferable to contain alkyl-1,10-decanediamine, and the total amount of aliphatic monoamine (C) is NC 1-3 The proportion of alkyl-1,10-decanediamine is, for example, 50% or more, preferably 60 mol% or more, more preferably 70% or more, even more preferably 80% or more, and particularly preferably 90% or more.

[0049] Furthermore, the content of the aliphatic monoamine (C)-derived component (hereinafter sometimes referred to as "component (C)") in the semi-aromatic polyamide of the present invention is preferably 0.01 to 3.0% of the content of the aliphatic diamine (B)-derived component (hereinafter sometimes referred to as "component (B)"), from the viewpoint of suppressing an excessively fast reaction rate in the dehydration condensation reaction and reducing molecular weight dispersion. The lower limit of the content of component (C) relative to the content of component (B) is preferably 0.05%, more preferably 0.10%, and even more preferably 0.15%, from the viewpoint of improving mechanical properties. Also, from the viewpoint of improving productivity with an appropriate polymerization rate, the upper limit of the content of component (C) relative to the content of component (B) is preferably 2.5%, more preferably 2.0%, even more preferably 1.5%, and particularly preferably 1.0%. The content of each component of the semi-aromatic polyamide is determined by gas chromatography analysis.

[0050] The semi-aromatic polyamide of the present invention may contain, in addition to components derived from aliphatic diamines (B), components derived from aromatic diamines such as xylylenediamine and benzenediamine, or components derived from alicyclic diamines such as cyclohexanediamine, as amine-derived components.

[0051] When the semi-aromatic polyamide of the present invention contains an aliphatic diamine (B) along with other diamines (e.g., aromatic diamines or alicyclic diamines), the content of diamines other than aliphatic diamine (B) (total content if two or more are included) is preferably 20 mol% or less, more preferably 10 mol% or less, relative to the total number of moles of raw material monomers of the semi-aromatic polyamide. Furthermore, the content of diamines other than aliphatic diamine (B) (total content if two or more are included) is preferably 20 mol% or less, more preferably 10 mol% or less, even more preferably 5 mol% or less, particularly preferably 1 mol% or less, and most preferably substantially absent, relative to the total amount of amine-derived components.

[0052] The semi-aromatic polyamide of the present invention may further contain components derived from lactams such as caprolactam and laurolactam, and components derived from ω-aminocarboxylic acids such as aminocaproic acid and 11-aminoundecanoic acid. However, these components are preferably present in an amount of 20 mol% or less, more preferably 10 mol% or less, even more preferably 5 mol% or less, particularly preferably 1 mol% or less, and most preferably substantially absent, relative to the total amount of components of the semi-aromatic polyamide.

[0053] The melting point of the semi-aromatic polyamide of the present invention is, for example, 280°C or higher, preferably 300°C or higher. The upper limit of the melting point is, for example, 360°C, preferably 350°C. Because the semi-aromatic polyamide of the present invention has the above melting point, it has excellent heat resistance and is suitable as a raw material for molded articles used in high-temperature environments.

[0054] The relative viscosity of the semi-aromatic polyamide of the present invention is preferably 1.8 or higher, and more preferably 2.0 or higher, from the viewpoint of improving mechanical properties. Furthermore, the relative viscosity is preferably 3.5 or lower, more preferably 3.1 or lower, and even more preferably 2.8 or lower, from the viewpoint of improving melt processability. The relative viscosity of the polyamide resin can be measured in 96% by mass sulfuric acid at a polyamide resin concentration of 1 g / dL and a temperature of 25°C, with reference to JIS K 6920.

[0055] The number-average molecular weight (Mn) of the semi-aromatic polyamide of the present invention is, for example, 8,000 to 30,000. From the viewpoint of improving mechanical properties, the lower limit of Mn is preferably 10,000, more preferably 12,000, and even more preferably 14,000 or higher. From the viewpoint of improving melt processability, the upper limit of Mn is preferably 28,000, more preferably 25,000, and even more preferably 20,000.

[0056] The molecular weight dispersion [weight-average molecular weight (Mw) / number-average molecular weight (Mn)] of the semi-aromatic polyamide of the present invention is, for example, 3.0 or less (e.g., 1.5 to 3.0), and preferably 2.9 or less. Mw and Mn can be determined by gel permeation chromatography (GPC).

[0057] [Method for producing semi-aromatic polyamides] The method for producing the semi-aromatic polyamide of the present invention is not particularly limited, but conventionally known methods such as heat polymerization and solution polymerization can be used. Among these, heat polymerization under atmospheric pressure is preferred because it is industrially advantageous.

[0058] The method for producing semi-aromatic polyamide by thermal polymerization is a method for producing the above-mentioned semi-aromatic polyamide through the following steps (i) and (ii). Step (i): A step of reacting a carboxylic acid component containing an aromatic dicarboxylic acid (A) with an amine component containing an aliphatic diamine (B) and an aliphatic monoamine (C) to produce a polymer precursor. Step (ii): A step of dehydrating and condensing the generated polymer precursor.

[0059] (Step (i)) Step (i) is a step in which a polymer precursor is produced by reacting a carboxylic acid component containing an aromatic dicarboxylic acid (A) with an amine component containing an aliphatic diamine (B) and an aliphatic monoamine (C).

[0060] The polymer precursors include nylon salts, which are equimolar reaction products of the carboxylic acid component and the amine component, and lower-order polymers of nylon salts.

[0061] The carboxylic acid component contains at least an aromatic dicarboxylic acid (A), and may also contain a monocarboxylic acid (D).

[0062] Examples of carboxylic acid components include the compounds exemplified above as carboxylic acids that form the carboxylic acid-derived components, as well as their derivatives.

[0063] Examples of amine components include the compounds exemplified as amines that form the amine-derived constituent components mentioned above.

[0064] Regarding the amounts of carboxylic acid and amine components used, the molar ratio (COOH / NH2) of the carboxyl group of the carboxylic acid component to the amino group of the amine component is preferably in the range of 40 / 60 to 60 / 40, and more preferably in the range of 45 / 55 to 55 / 45.

[0065] When the carboxylic acid component includes an aromatic dicarboxylic acid (A) and a monocarboxylic acid (D), the content of monocarboxylic acid (D) is, for example, 0.01 to 8.0 mol% of the content of aromatic dicarboxylic acid (A). The lower limit of the monocarboxylic acid (D) content is preferably 0.1 mol%, more preferably 0.3 mol%, even more preferably 0.5 mol%, even more preferably 1.0 mol%, and particularly preferably 1.5 mol%, from the viewpoint of improving the melting fluidity and processability of the resulting semi-aromatic polyamide. The upper limit of the monocarboxylic acid (D) content is preferably 7 mol%, more preferably 6 mol%, even more preferably 5 mol%, and particularly preferably 4.5%, from the viewpoint of improving the mechanical properties of the resulting semi-aromatic polyamide.

[0066] The amine component includes an aliphatic diamine (B) and an aliphatic monoamine (C). The content of the aliphatic monoamine (C) in the amine component is, for example, 0.01 to 3.0% of the content of the aliphatic diamine (B). The lower limit of the content of the aliphatic monoamine (C) is preferably 0.05%, more preferably 0.10%, even more preferably 0.15%, particularly preferably 0.5%, most preferably 1.00%, and especially preferably 2.00%. By adjusting the content of the aliphatic monoamine (C) within the above range, the maximum discharge rate of condensation water in step (ii) can be set to 25 g / kg·min or less, and a semi-aromatic polyamide with high molecular weight and low molecular weight dispersion can be obtained.

[0067] This process can be carried out, for example, by heating the carboxylic acid component at a temperature below the melting point of the aromatic dicarboxylic acid (A) and above the melting point of the aliphatic diamine (B) under atmospheric pressure and in the substantial absence of water, while stirring and maintaining the aromatic dicarboxylic acid (A) in powder form, and then adding the amine component.

[0068] This process can also be carried out by stirring a suspension containing a molten amine component, a solid carboxylic acid component, and water, and reacting the amine component and the carboxylic acid component under pressure at a temperature below the melting point of the final semi-aromatic polyamide. In this method, crushing may be performed during the reaction, or the product may be crushed after the reaction.

[0069] As for process (i), the former is preferable because it allows for easy control of the shape of the reactants and can be manufactured under atmospheric pressure.

[0070] In this process, a polymerization catalyst may be used to improve reaction efficiency. Examples of polymerization catalysts include phosphoric acid, phosphorous acid, hypophosphorous acid, or salts thereof. The amount of polymerization catalyst used is, for example, 0.02 to 2 mol% relative to the total number of moles of the raw material monomers of the semi-aromatic polyamide (or the total number of moles of the carboxylic acid component and the amine component).

[0071] (Step (ii)) Step (ii) is a step of dehydrating and condensing the polymer precursor produced in step (i), preferably a step of dehydrating and condensing in a solid state.

[0072] The dehydration condensation of the polymer precursor is preferably carried out at a temperature below the melting point of the final semi-aromatic polyamide (e.g., 180-270°C). By subjecting the polymer precursor to a dehydration condensation reaction for a predetermined time (e.g., 0.5-10 hours), a high molecular weight semi-aromatic polyamide can be obtained. The dehydration condensation of the polymer precursor is preferably carried out in an inert gas stream such as nitrogen.

[0073] In the present invention, as described above, the polymer precursor subjected to the dehydration condensation reaction contains an aliphatic monoamine (C) to an aliphatic diamine (B) in a specific ratio (preferably, it contains an aliphatic monoamine (C) to an aliphatic diamine (B) in a specific ratio, and an aromatic dicarboxylic acid (A) to a monocarboxylic acid (D) in a specific ratio), so the polymerization rate is moderate and not too fast. The dehydration condensation reaction proceeds gently. The maximum discharge rate of condensation water relative to the total amount of carboxylic acid and amine components charged is, for example, 25 g / kg·min or less (preferably 5 to 25 g / kg·min, more preferably 5 to 20 g / kg·min, and even more preferably 5 to 18 g / kg·min). As a result, a semi-aromatic polyamide with high molecular weight and low molecular weight dispersion is obtained. The molecular weight dispersion Mw / Mn is, for example, 3.0 or less (for example, 1.5 to 3.0), and preferably 2.9 or less.

[0074] The reaction apparatus for steps (i) and (ii) is not particularly limited, and known apparatus can be used. Steps (i) and (ii) may be carried out using the same apparatus or using different apparatus. The heating method is not particularly limited, but examples include heating the reaction vessel via a medium such as water, steam, or heat transfer oil; directly heating the reaction vessel with an electric heater; or utilizing the heat generated by stirring or the frictional heat associated with the movement of the contents. These methods may also be combined.

[0075] [Resin composition] The resin composition of the present invention comprises at least the above-mentioned semi-aromatic polyamide.

[0076] The resin composition of the present invention may contain only the above-mentioned semi-aromatic polyamide, or it may contain other components.

[0077] The resin composition of the present invention may contain one or more other resin components (e.g., thermoplastic resins) in addition to the semi-aromatic polyamide mentioned above as a resin component. However, the proportion of the semi-aromatic polyamide in the total amount of resin components contained in the resin composition is, for example, 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more.

[0078] Examples of thermoplastic resins other than the semi-aromatic polyamides mentioned above include polyamide resins other than the semi-aromatic polyamides of the present invention (hereinafter sometimes abbreviated as "other polyamides"), polyphenylene sulfide, polyester resin, polyarylate resin, polyphenylene ether resin, polycarbonate resin, polyethylene, polypropylene resin, polystyrene resin, and acrylonitrile-styrene copolymer resin. These can be contained individually or in combination of two or more.

[0079] Other examples of polyamides include aliphatic polyamides (including polyamides having an alicyclic structure) and semi-aromatic polyamides other than those mentioned above. These polyamides may also be amorphous polyamides.

[0080] Examples of aliphatic polyamides include polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 410, polyamide 412, polyamide 56, polyamide 510, polyamide 512, polyamide 66, polyamide 610, polyamide 612, polyamide 1010, polyamide 1012, polyamide 6 / 66, polyamide 66 / 1010, polyamide 66 / 612, polyamide 2Me5C, polyamide 6C, polyamide 8C, polyamide 9C, polyamide 10C, and polyamide 12C. Note that "C" represents 1,4-cyclohexanedicarboxylic acid and "2Me5" represents 2-methylpentamethylenediamine.

[0081] Examples of amorphous polyamides include the polycondensate of isophthalic acid / terephthalic acid / 1,6-hexanediamine / bis(3-methyl-4-aminocyclohexyl)methane, the polycondensate of terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, the polycondensate of isophthalic acid / bis(3-methyl-4-aminocyclohexyl)methane / ω-laurolactom, and the polycondensate of isophthalic acid / terephthalic acid / 1,6-hexanediamine. Examples include polycondensates of isophthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, polycondensates of isophthalic acid / terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, polycondensates of isophthalic acid / bis(3-methyl-4-aminocyclohexyl)methane / ω-laurolactom, and polycondensates of isophthalic acid / terephthalic acid / other diamine components. Amorphous polyamides refer to polyamides in which the heat of fusion measured using a differential scanning calorimeter (DSC) at a heating rate of 20°C / min under a nitrogen atmosphere is 1 J / g or less.

[0082] Other semi-aromatic polyamides besides those mentioned above include those mainly composed of aliphatic dicarboxylic acids and aromatic diamines. Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanediic acid, and dodecanediic acid. Examples of aromatic dicarboxylic acids include paraxylylenediamine, metaxylylenediamine, bis(4-aminophenyl) ether, paraphenylenediamine, bis(aminomethyl)naphthalene, aminophenylmethylamine, and aminophenylethylamine.

[0083] The resin composition of the present invention may contain other components (e.g., additives) in addition to the resin component, but the proportion of components other than the resin component in the total amount of the resin composition of the present invention is, for example, 50 mol% or less, preferably 40 mol% or less, more preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, and particularly preferably 5 mol% or less.

[0084] Examples of additives include fibrous reinforcing materials, plate-like reinforcing materials, spherical reinforcing materials, impact-resistant materials, antistatic agents, conductivity-imparting agents, thermally conductive fillers, heat stabilizers, light stabilizers, sliding properties improvers, fluidity improvers, thickeners, flame retardants, flame retardant aids, colorants, mold release agents, and lubricants. These can be included individually or in combination of two or more.

[0085] Examples of fibrous reinforcing materials include carbon fibers, glass fibers, boron fibers, asbestos fibers, polyvinyl alcohol fibers, polyester fibers, acrylic fibers, all-aromatic polyamide fibers, polybenzoxazole fibers, polytetrafluoroethylene fibers, kenaf fibers, bamboo fibers, hemp fibers, bagasse fibers, high-strength polyethylene fibers, alumina fibers, silicon carbide fibers, potassium titanate fibers, brass fibers, stainless steel fibers, steel fibers, ceramic fibers, basalt fibers, sepiolite, and palygorskite. By adding fibrous reinforcing materials to a resin composition, the mechanical strength of the resin composition can be improved. Among the fibrous reinforcing materials, glass fibers, carbon fibers, all-aromatic polyamide fibers, and metal fibers are preferred due to their high heat resistance and availability.

[0086] The fiber length of the fibrous reinforcing material is not particularly limited, but is preferably 0.1 to 7 mm, and more preferably 0.5 to 6 mm. A fiber length of 0.1 to 7 mm allows for improved mechanical strength without adversely affecting moldability. Furthermore, the fiber diameter of the fibrous reinforcing material is not particularly limited, but is preferably 3 to 20 μm, and more preferably 5 to 14 μm. Using a fibrous reinforcing material with a fiber diameter of 3 to 20 μm prevents the fibrous reinforcing material from breaking during kneading with a resin composition containing molten semi-aromatic polyamide, thereby improving the mechanical strength of the resin composition. Examples of cross-sectional shapes of the fibrous reinforcing material include circular, rectangular, elliptical, and other irregular cross-sections.

[0087] Examples of plate-shaped reinforcing materials include talc, mica, sericite, glass flakes, plate-shaped calcium carbonate, plate-shaped aluminum hydroxide, graphite, kaolin, swellable layered silicate, and aluminum flakes. Adding plate-shaped reinforcing materials to a resin composition can improve the dimensional stability of the resin composition.

[0088] Examples of spherical reinforcing materials include crystalline silica, fused silica, glass beads, alumina, and spherical calcium carbonate. By adding spherical reinforcing materials to a resin composition, the anisotropy of the resin composition can be suppressed, thereby improving dimensional stability.

[0089] Fibrous reinforcing materials, plate-shaped reinforcing materials, and spherical reinforcing materials are preferably surface-treated with a silane coupling agent or the like to improve dispersibility. Examples of silane coupling agents include vinylsilane-based coupling agents, acrylicsilane-based coupling agents, epoxysilane-based coupling agents, and aminosilane-based coupling agents. Among these, aminosilane-based coupling agents are preferred because they have a high adhesion effect with semi-aromatic polyamides and excellent heat resistance. Silane coupling agents may also be used in combination with sizing agents.

[0090] Examples of impact-resistant materials include olefin polymers such as (ethylene and / or propylene)-α-olefin copolymers and (ethylene and / or propylene)-(α,β-unsaturated carboxylic acid and / or unsaturated carboxylic acid and / or unsaturated carboxylic acid ester) copolymers, and elastomers such as styrene elastomers. By adding impact-resistant materials to a resin composition, the impact resistance and weld strength of the resin composition can be improved.

[0091] Examples of antistatic agents include anionic antistatic agents, cationic antistatic agents, and nonionic antistatic agents.

[0092] Examples of conductivity imparting agents include carbon black, carbon fibers, metal fibers, carbon nanotubes, and carbon nanostructures.

[0093] By adding antistatic agents or conductive agents to the resin composition, the surface resistivity and volume resistivity of the resin composition can be reduced.

[0094] Examples of thermally conductive fillers include talc, aluminum oxide, magnesium oxide, zinc oxide, magnesium carbonate, silicon carbide, aluminum nitride, boron nitride, silicon nitride, carbon, and graphite. By adding a thermally conductive filler to a resin composition, the thermal conductivity of the resin composition can be improved.

[0095] Examples of heat stabilizers include hindered phenol compounds, phosphite compounds, hindered amine compounds, triazine compounds, sulfur compounds, copper-based heat stabilizers, and polyhydric alcohol-based heat stabilizers. By adding a heat stabilizer to the resin composition, it is possible to suppress the decrease in molecular weight and color degradation of the semi-aromatic polyamide in the resin composition. When using a heat stabilizer, its content is preferably more than 0 parts by mass and 6 parts by mass or less, and more preferably more than 0 parts by mass and 3 parts by mass or less, per 100 parts by mass of semi-aromatic polyamide.

[0096] Examples of light stabilizers include benzophenone compounds, benzotriazole compounds, salicylate compounds, hindered amine compounds, and hindered phenol compounds. By adding a light stabilizer to the resin composition, it is possible to suppress the decrease in molecular weight of the semi-aromatic polyamide in the resin composition due to ultraviolet light. When a light stabilizer is used, its content is preferably more than 0 parts by mass and 6 parts by mass or less, and more preferably more than 0 parts by mass and 3 parts by mass or less, per 100 parts by mass of semi-aromatic polyamide.

[0097] Examples of sliding properties improving materials include fluororesins such as polytetrafluoroethylene, silicones such as polydimethylsiloxane and fluorine-modified polydimethylsiloxane, ultra-high molecular weight polyethylene or its acid-modified products, molybdenum disulfide, and graphite.

[0098] Examples of flame retardants include bromine-containing flame retardants, nitrogen-containing flame retardants, phosphorus-containing flame retardants, nitrogen-phosphorus-containing flame retardants, and hydrated metal-based flame retardants.

[0099] Examples of bromine-containing flame retardants include brominated polystyrene, polybrominated styrene, and brominated polyphenylene ether. Among these, those containing 40 to 80% by mass of bromine are preferred, and those containing 50 to 70% by mass are more preferred, due to their high flame retardancy-enhancing effect. These bromine-containing flame retardants are preferably used in combination with flame retardant additives such as antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonate, tin(IV) oxide, iron(III) oxide, zinc oxide, and zinc borate.

[0100] Examples of nitrogen-containing flame retardants include melamine compounds, salts of cyanuric acid or isocyanuric acid with melamine compounds, and salts of phosphoric acid or polyphosphates with ammonia or melamine compounds.

[0101] Examples of phosphorus-containing flame retardants include phosphate ester compounds, phosphinates, and diphosphinates.

[0102] Examples of nitrogen-phosphorus-containing flame retardants include adducts formed from melamine or its condensation products and phosphoric acid (melamine adducts). Examples of phosphoric acid constituting these melamine adducts include orthophosphoric acid, phosphonic acid, phosphinic acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, and tetraphosphoric acid.

[0103] Examples of hydrated metal flame retardants include aluminum hydroxide, boehmite, magnesium hydroxide, calcium hydroxide, and calcium aluminate.

[0104] Other examples of flame retardants include inorganic flame retardants such as zinc borate and mixtures of zinc borate and other zinc salts.

[0105] Examples of coloring agents include titanium dioxide, zinc oxide, zinc sulfide, zinc sulfate, barium sulfate, calcium carbonate, aluminum oxide, carbon black, nigrosine, and red iron oxide.

[0106] The resin composition of the present invention can be prepared by blending the above-mentioned semi-aromatic polyamide with thermoplastic resins other than the above-mentioned semi-aromatic polyamide and various additives as needed. A melt kneading method is preferred as the method. Melt kneading can be performed using, for example, a batch-type kneader such as a Brabender, a Banbury mixer, a Henschel mixer, a helical rotor, rolls, a single-screw extruder, a twin-screw extruder, etc. The melt kneading temperature is not particularly limited as long as the above-mentioned semi-aromatic polyamide melts without decomposing, but a temperature of (melting point of semi-aromatic polyamide - 20°C) or higher and (melting point of semi-aromatic polyamide + 40°C) or lower is preferred.

[0107] The resin composition of the present invention exhibits excellent moldability and can form molded articles with superior waterproofing and mechanical properties. Therefore, it can be used as a resin for molding articles in a wide range of applications, such as automotive parts, electrical and electronic components, sliding parts, general merchandise, industrial equipment parts, and civil engineering and construction materials.

[0108] The resin composition of the present invention is preferably in pellet form because it is easy to handle during melt processing and improves workability.

[0109] [Molded body] The molded article of the present invention is a molded article made of a solidified product of the above resin composition.

[0110] Because the molded article of the present invention contains the above-mentioned semi-aromatic polyamide (more specifically, a solidified product of the above-mentioned semi-aromatic polyamide), it has excellent water resistance, and the saturated moisture absorption rate obtained by the method of the example is, for example, 2.0% or less, preferably 1.5% or less, and more preferably 1.20% or less.

[0111] Furthermore, the molded articles of the present invention have excellent mechanical strength, and the tensile creep strain obtained by the method of the examples is, for example, 10% or less, preferably 6% or less, and more preferably 5% or less.

[0112] The molded article of the present invention can be manufactured, for example, by subjecting the above resin composition to a molding process. Examples of known molding methods include injection molding, extrusion molding, blow molding, sintering, compression molding, cutting, film formation (T-die extrusion, inflation molding, etc.), and spinning.

[0113] Among the methods for molding the above resin composition, injection molding is preferred because it significantly improves mechanical properties and moldability, and offers excellent productivity. The injection molding machine used for injection molding is not particularly limited, but examples include screw-in-line injection molding machines and plunger-type injection molding machines.

[0114] The above resin composition is heated and melted in the cylinder of an injection molding machine, the molten resin composition is injected and filled into a mold having a predetermined shape of void, and when the resin composition filled in the mold is cooled, the resin composition solidifies and a molded body of the predetermined shape is formed. The temperature of the resin composition during injection molding is preferably (melting point of semi-aromatic polyamide - 20°C) or higher and (melting point of semi-aromatic polyamide + 40°C). Furthermore, the resin composition used for injection molding is preferably sufficiently dry, and the moisture content is preferably less than 0.3% by mass, more preferably less than 0.1% by mass, and particularly preferably less than 0.06% by mass. By drying the above resin composition and reducing the moisture content, foaming of the resin composition in the cylinder of the injection molding machine is suppressed, and a molded body with high shape accuracy can be obtained.

[0115] The molded articles of the present invention include, for example, molded articles for a wide range of applications such as automotive parts, electrical and electronic components, sliding parts, general merchandise, industrial equipment parts, and civil engineering and construction supplies.

[0116] Examples of automotive parts include thermostat components, IGBT module components for inverters, actuator components, insulators, motor insulators, radiator components, radiator hoses, various valves, exhaust finishers, power device housings, ECU housings, motor components, coil components, resolver components, cable sheathing materials, in-vehicle camera housings, in-vehicle camera lens holders, in-vehicle connectors, engine mounts, intercoolers, bearing retainers, oil seal rings, chain covers, ball joints, chain tensioners, clutch components, torsion sheets, starter gears, reduction gears, internal gears, in-vehicle lithium-ion battery trays, in-vehicle high-voltage fuse housings, in-vehicle electrical circuit breaker housings, and automotive turbocharger impellers.

[0117] Examples of electrical and electronic components include connectors, ECU connectors, main tenlock connectors, modular jacks, reflectors, LED reflectors, switches, sensors, sockets, pin sockets, capacitors, jacks, fuse holders, relays, coil bobbins, circuit breakers, circuit components, electromagnetic switches, holders, covers, plugs, housing components for electrical and electronic equipment such as portable computers and word processors, impellers, vacuum cleaner impellers, resistors, variable resistors, ICs, LED housings, camera housings, camera barrels, camera lens holders, tact switches, lighting tact switches, hair iron housings, hair iron combs, fully molded DC-only miniature switches, organic EL display switches, materials for 3D printers, and materials for bonded magnets for motors.

[0118] Examples of sliding parts include bearings, bearing cages, various gears, cams, end faces of mechanical seals, valve seats, V-rings, rod packings, piston rings, rotating shafts and sleeves of compressors, pistons, vanes, rotors, and oil seals. Furthermore, it can be suitably used in both lubricated and unlubricated conditions, using water, various oils, or greases as lubricants.

[0119] Examples of miscellaneous goods include trays, sheets, cable ties, watch frames, and zippers.

[0120] Examples of industrial equipment parts include insulators, connectors, gears, switches, screws, washers, bearing retainers, sensors, impellers, and Plarail chains.

[0121] Examples of civil engineering and construction supplies include fences, storage boxes, construction electrical panels, anchor bolt guides, anchor rivets, solar panel risers, and wind turbine brake pads.

[0122] Furthermore, the above resin composition can be subjected to known film-forming methods such as T-die extrusion and inflation molding to form films and sheets. The films and sheets thus obtained can be used, for example, in applications such as speaker diaphragms and film capacitors.

[0123] Furthermore, various fibers can be formed by subjecting the above resin composition to known spinning methods such as melt spinning, flash spinning, and electrospinning. The fibers obtained in this way can be used for applications such as airbag base fabric, heat-resistant filters, reinforcing fibers for radiator hoses, brush bristle, fishing line, tire cord, artificial turf, carpets, fishing nets, ropes, filter fibers, and seat fibers.

[0124] The configurations and combinations thereof described above are merely examples, and additions, omissions, substitutions, and modifications to the configurations are permitted as appropriate, without departing from the spirit of the present invention. Furthermore, the present invention is not limited by its embodiments. [Examples]

[0125] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0126] 1. Evaluation Method The evaluation and measurement of semi-aromatic polyamides were performed using the following method. (1) Melting point Using a differential scanning calorimeter DSC7020 (manufactured by Hitachi High-Tech Corporation), semi-aromatic polyamide powder was heated to 370°C at a heating rate of 20°C / min under a nitrogen atmosphere, held at 370°C for 5 minutes, cooled to 0°C at a heating rate of 20°C / min, held at 0°C for another 5 minutes, and then heated again to 370°C at a heating rate of 20°C / min. The peak temperature of the endothermic peak at this point was defined as the melting point.

[0127] (2) Relative viscosity The relative viscosity of semi-aromatic polyamide powder was measured using 96% sulfuric acid as a solvent at 25°C and a concentration of 1 g / dL.

[0128] (3) Molecular weight dispersity Using a gel permeation chromatography system (manufactured by Tosoh Corporation), sample solutions prepared by the following method were subjected to GPC analysis under the following conditions. The molecular weight distribution was then determined using a calibration curve created with polymethyl methacrylate (manufactured by Polymer Laboratories, Inc.) as the standard sample. Subsequently, the weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight dispersion (Mw / Mn) were calculated from the molecular weight distribution. <Preparation of sample solution> 5 mg of semi-aromatic polyamide powder was dissolved in 2 mL of hexafluoroisopropanol containing 10 mM sodium trifluoroacetate, and the solution was filtered through a disc filter to obtain the sample solution. <Condition> • Detector: Differential refractive index detector • Eluent: 10mM sodium trifluoroacetate-containing hexafluoroisopropanol • Column: TSKgel SuperHM-M manufactured by Tosoh Corporation ·Flow rate: 0.2mL / min ·Temperature: 40℃

[0129] (4) The ratio of aliphatic monoamines (C) contained in aliphatic diamines (B) used in the production of semi-aromatic polyamides. Using an Agilent Technologies gas chromatography (GC) system, sample solutions prepared under the following conditions were subjected to GC / FID analysis to determine the peak area values ​​of aliphatic monoamine (C) (C'-area) and aliphatic diamine (B) (B'-area). Then, the ratio of the amount of aliphatic monoamine (C) used (C') to the amount of aliphatic diamine (B) used (B') was calculated using the following formula. (C') / (B')(%)=(C'-area) / (B'-area)×100 <Sample Preparation> 0.5 mg of aliphatic diamine (B) was dissolved in methanol to make a total volume of 10 mL. The solution was filtered to remove insoluble matter and obtained the sample solution for measurement. <Condition> • Column: Agilent Technologies HP-1ms (30m x 0.32mm ID, df=1.0μm) • Carrier gas: Helium Oven temperature: 100-280°C (heating rate: 10°C / min) • Detector: Flame ionization detector (FID) Detector temperature: 250℃ ·Inlet temperature: 250℃

[0130] (5) The ratio of component (C) derived from aliphatic monoamine (C) to component (B) derived from aliphatic diamine (B) in the obtained semi-aromatic polyamide. Using a gas chromatography (GC) instrument (manufactured by Agilent Technologies, Inc.), GC / FID analysis was performed on sample solutions prepared by the following method under the following conditions to determine the peak area values ​​(B-area) of component (B) derived from aliphatic diamine (B) and the peak area values ​​(C-area) of component (C) derived from aliphatic monoamine (C). Then, the ratio of component (C) to component (B) was calculated using the following formula. (C) / (B)(%)=[(C-area) / (B-area)]×100 <Preparation of sample solution> 10 mg of semi-aromatic polyamide powder was dissolved in 3 mL of 47% hydrobrominated acid at 135°C. After cooling, 5 mL of aqueous sodium hydroxide solution was added to neutralize the mixture. The sample solution and 2 mL of 1-butanol were added to a separatory funnel, stirred, and allowed to stand. The 1-butanol layer was collected and filtered to obtain the sample solution for measurement. <Condition> • Column: Agilent Technologies HP-1ms (30m x 0.32mm ID, df=1.0μm) • Carrier gas: Helium Oven temperature: 100-280°C (heating rate: 10°C / min) • Detector: Flame ionization detector (FID) Detector temperature: 250℃ ·Inlet temperature: 250℃

[0131] (6) Saturated moisture absorption rate Semi-aromatic polyamide resin pellets were injection molded using an injection molding machine (J35AD-30H model, manufactured by Japan Steel Works Ltd.) under the following conditions: cylinder temperature (melting point + 15°C), mold temperature 130°C, and molding cycle of 30 seconds. Plate-shaped test specimens measuring 20 x 20 mm and 2 mm thick were then produced. The mass of the obtained plate-shaped test specimen was measured and taken as the mass before moisture absorption treatment. Then, the plate-shaped test specimen was left to stand for 1000 hours under conditions of 70°C and 62% relative humidity. After that, the mass of the plate-shaped test specimen was measured and taken as the mass after moisture absorption treatment. The saturation moisture absorption rate was then calculated using the following formula. Saturation moisture absorption rate [%] = (Mass after moisture absorption treatment - Mass before moisture absorption treatment) / Mass before moisture absorption treatment × 100

[0132] (7) Tensile creep strain Dumbbell-shaped test specimens were prepared by injection molding semi-aromatic polyamide resin pellets using an injection molding machine (FANUC S2000i-100B model) under the following conditions: cylinder temperature (melting point + 15°C), mold temperature 130°C, and molding cycle 35 seconds. Using a method based on JIS K 7115, a tensile creep test was performed on the obtained dumbbell test specimens under a tensile load of 30 MPa in an 80°C atmosphere, and the tensile strain was measured after 100 hours.

[0133] 2.Raw materials The raw materials used in the examples and comparative examples are shown below. (1) Aromatic dicarboxylic acid (A) TPA: Terephthalic acid IPA: Isophthalic acid

[0134] (2) Aliphatic diamines (B) • DDA-1: 1,10-decanediamine (E-DDA content: 0%) • DDA-2: 1,10-decanediamine (E-DDA content: 0.2%) • NDA: 1,9-nonanediamine • HDA: 1,6-Hexanediamine

[0135] (3) Aliphatic monoamines (C) • E-DDA: N-ethyl-1,10-decanediamine • E-NDA: N-ethyl-1,9-nonanediamine • E-HDA: N-ethyl-1,6-hexanediamine

[0136] (4) Monocarboxylic acid (D) • STA: Stearic acid ·BA:benzoic acid

[0137] Example 1 (Semi-aromatic polyamide (A-1)) 4.72 kg of powdered terephthalic acid (TPA) as aromatic dicarboxylic acid (A), 0.28 kg of stearic acid (STA) as monocarboxylic acid (D), and 9.3 g of sodium hypophosphite monohydrate as polymerization catalyst were placed in a ribbon blender type reactor and heated to 170°C under nitrogen sealing with stirring at 30 rpm. Then, while maintaining the temperature at 170°C and the rotation speed at 30 rpm, 4.99 kg of aliphatic diamine (B) 1,10-decanediamine (DDA-1), which had been heated and mixed at 100°C, and 0.01 kg of aliphatic monoamine (C) N-ethyl-1,10-decanediamine (E-DDA), were continuously added over 2.5 hours using a liquid injection device to obtain a polymer precursor. The total amount of raw material monomers used was 10 kg, and the molar ratio of the raw material monomers was TPA:DDA:E-DDA:STA = 48.5:49.3:0.3:1.9 (the equivalent ratio of the functional groups of the raw material monomers was TPA:DDA:E-DDA:STA = 49.0:49.7:0.3:1.0).

[0138] Next, the obtained polymer precursor was subjected to dehydration condensation polymerization in the same reactor under a nitrogen stream at 250°C and a rotation speed of 30 rpm for 8 hours to obtain a semi-aromatic polyamide powder. During this process, the condensation water generated during polymerization was cooled and collected, and the weight of the discharged water was weighed every 5 minutes to measure the water discharge rate (g / kg·min) relative to the total amount charged. The maximum value of the water discharge rate relative to the total amount charged was then determined.

[0139] Subsequently, the obtained semi-aromatic polyamide powder was formed into strands using a twin-screw kneader, the strands were cooled and solidified in a water bath, and then cut with a pelletizer to obtain semi-aromatic polyamide resin pellets. Plate-shaped test specimens were prepared from the obtained semi-aromatic polyamide resin pellets and their saturation moisture absorption rate was measured. Dumbbell-shaped test specimens were also prepared and their tensile creep strain was measured.

[0140] Examples 2-12, Comparative Examples 1-3 Except for changing the raw materials used, the same procedure as in Example 1 was performed to obtain a semi-aromatic polyamide having the composition shown in the table below, and semi-aromatic polyamide resin pellets were obtained. The semi-aromatic polyamide resin pellets were then evaluated in the same manner as in Example 1.

[0141] [Table 1]

[0142] [Table 2]

[0143] The examples show that in the dehydration condensation polymerization reaction between the carboxylic acid component and the amine component, using aliphatic monoamine (C) and aliphatic diamine (B) in specific proportions results in a slower rate of condensation water discharge, indicating a slower reaction. Furthermore, it is evident that a semi-aromatic polyamide with excellent uniformity can be produced through this slow dehydration condensation polymerization reaction.

[0144] Furthermore, the examples show that semi-aromatic polyamides containing a specific ratio of aliphatic monoamine (C) components and aliphatic diamine (B) components have a low and uniform molecular weight dispersion (Mw / Mn) and exhibit excellent water resistance and mechanical properties.

[0145] On the other hand, Comparative Examples 1 and 2 show that when the amount of aliphatic monoamine (C) used relative to aliphatic diamine (B) is insufficient, the rate of discharge of condensation water during dehydration condensation polymerization is high, and the dehydration condensation polymerization reaction between the carboxylic acid component and the amine component proceeds rapidly. Furthermore, it can be seen that the semi-aromatic polyamide obtained by a rapid dehydration condensation polymerization reaction has a high degree of molecular weight dispersion and is inferior in terms of water resistance and mechanical properties. Furthermore, Comparative Example 3 shows that when the amount of aliphatic monoamine (C) used relative to aliphatic diamine (B) is excessive, the rate of condensation water discharge during dehydration condensation polymerization is low, the rate of dehydration condensation polymerization between the carboxylic acid component and the amine component proceeds slowly, and sufficient high molecular weight cannot be achieved. Additionally, the resulting semi-aromatic polyamide is inferior in terms of mechanical properties.

Claims

1. A component derived from an aromatic dicarboxylic acid (A), a component derived from an aliphatic diamine (B), and the following formula (c) H ２ N-R １ -NH-R ２ (c) (In the formula, R １ R indicates an alkylene group, ２ (This indicates an alkyl group.) It contains a component derived from an aliphatic monoamine (C) represented by, The ratio ([C-area / B-area] × 100) of the peak area value of the component derived from aliphatic monoamine (C) (C-area) to the peak area value of the component derived from aliphatic diamine (B) (B-area), as determined by gas chromatography analysis, is between 0.01% and 3.0%. A semi-aromatic polyamide with a molecular weight dispersion ratio (Mw / Mn) of 3.0 or less.

2. Furthermore, it contains components derived from monocarboxylic acid (D), The semi-aromatic polyamide according to claim 1, wherein the content of the component derived from monocarboxylic acid (D) is 0.01 to 8.0 mol% of the content of the component derived from aromatic dicarboxylic acid (A).

3. The semi-aromatic polyamide according to claim 1 or 2, wherein the aromatic dicarboxylic acid component (A) contains terephthalic acid.

4. The aliphatic diamine component (B) is given by the following formula (b) H ２ N-R １ ’-NH ２ (b) (In the formula, R １ ' represents an alkylene group having 6 or more carbon atoms) It contains a compound represented by, Aliphatic monoamines (C) are given by the following formula (c1) H ２ N-R １ ’-NH-R ２ ’ (c1) (In the formula, R １ ' is the same as above, R ２ (' indicates an alkyl group with 1 to 3 carbon atoms) A semi-aromatic polyamide according to claim 1 or 2, comprising a compound represented by [the specified formula].

5. A resin composition comprising the semi-aromatic polyamide described in claim 1 or 2.

6. A molded article of the resin composition according to claim 5.

7. A method for producing a semi-aromatic polyamide to obtain the semi-aromatic polyamide described in claim 1 or 2, comprising the following steps 1 and 2, wherein in step 1, the ratio of the peak area value of an aliphatic monoamine (C) (C'-area) to the peak area value of an aliphatic diamine (B) (B'-area) ([C'-area / B'-area] × 100), determined by gas chromatography analysis, is set to 0.01 to 3.0%, thereby setting the maximum discharge rate of condensation water relative to the total amount of carboxylic acid and amine components charged by dehydration condensation in step 2 to 25 g / kg·min or less. Step 1: A carboxylic acid component containing an aromatic dicarboxylic acid (A), an aliphatic diamine (B), and the following formula (c) H ２ N-R １ -NH-R ２ (c) (In the formula, R １ R indicates an alkylene group, ２ (This indicates an alkyl group.) A process to produce a polymer precursor by reacting an aliphatic monoamine (C) represented by with an amine component. Step 2: Dehydration condensation of the generated polymer precursor.

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