Polyamide containing asymmetric diamine

Abstract

Provided is a polyamide having high heat resistance and good moldability.　This polyamide contains a structural unit derived from an aromatic dicarboxylic acid or a derivative thereof and a structural unit derived from a diamine, wherein the structural unit derived from a diamine contains a structural unit derived from a C8-12 aliphatic diamine and a structural unit derived from a diamine represented by formula (I). [In formula (I), R1 to R5 are each independently a hydrogen atom or a C1-6 aliphatic group and a plurality of R1 may be the same or different. r represents 4. n is an integer of 0-6, m is an integer of 1-6, and n and m are different integers.]

Description

Polyamides containing asymmetric diamines

[0001] The present invention relates to a polyamide containing structural units derived from a specific asymmetric diamine, and a method for producing the polyamide.

[0002] Diamines constituting polyimide-based resins such as polyamide resins, polyimide resins, and polyamideimide resins usually have a symmetric structure from the viewpoint of polymerizability. On the other hand, structurally asymmetric diamines are also known. Patent Document 1 describes a polyamide resin using an asymmetric diamine represented by formula (I) as a diamine component.

[0003]

[0004] Patent Publication No. 2023-177577

[0005] Among polyamides, aromatic polyamides having aromatic rings in their structural units often have a high glass transition temperature and good heat resistance, whereas aromatic polyamides with high heat resistance often also have a high melting point and tend to have poor moldability.

[0006] When a structurally asymmetric diamine is used as the diamine component of a polyamide, the melting point tends to be lower and the moldability tends to be improved compared to polyamides using only structurally symmetric diamines. However, there is still a demand for polyamides that have better moldability while maintaining high heat resistance.

[0007] The present invention has been made to solve the above problems, and an object of the present invention is to provide a polyamide having high heat resistance and good molding processability.

[0008] The present invention provides the following aspects.

[0009] [1] A copolymer comprising a structural unit derived from an aromatic dicarboxylic acid or a derivative thereof and a structural unit derived from a diamine, wherein the diamine-derived structural unit is a structural unit derived from an aliphatic diamine having 8 to 12 carbon atoms and a structural unit of formula (I):

[0010] [In formula (I), R １ ~R ５each independently represents a hydrogen atom or an aliphatic group having 1 to 6 carbon atoms, and multiple R １ may be the same or different. r represents 4. n represents an integer of 0 to 6, m represents an integer of 1 to 6, and n and m are different integers.]

[0011] [2] The polyamide according to [1], wherein the aliphatic diamine is a linear aliphatic diamine.

[0012] [3] The polyamide according to [1] or [2], wherein the diamine-derived structural units further contain aromatic diamine-derived structural units.

[0013] [4] The polyamide according to any one of [1] to [3], wherein n is 0 in the formula (I).

[0014] [5] The polyamide according to any one of [1] to [4], wherein the aromatic dicarboxylic acid is terephthalic acid, isophthalic acid, or phthalic acid.

[0015] [6] The polyamide according to any one of [1] to [5], wherein the aliphatic diamine is 1,10-decanediamine.

[0016] [7] The polyamide according to any one of [1] to [6], wherein the proportion of the diamine-derived structural units represented by formula (I) is 30 mol% or less, preferably 10 to 30 mol%, more preferably 15 to 25 mol%, relative to the total molar amount of the diamine-derived structural units constituting the polyamide.

[0017] [8] The polyamide according to any one of [1] to [7], having a glass transition temperature of 115°C or higher, preferably 115 to 250°C, more preferably 118 to 200°C, even more preferably 120 to 150°C, and particularly preferably 124 to 135°C, and a melting point of 390°C or lower, preferably 200 to 390°C, more preferably 220 to 350°C, even more preferably 250 to 320°C, and particularly preferably 270 to 300°C.

[0018] [9] Aromatic dicarboxylic acid or a derivative thereof, an aliphatic diamine having 8 to 12 carbon atoms, and a compound of formula (I):

[0019] [In formula (I), R １ ~R ５ each independently represents a hydrogen atom or an aliphatic group having 1 to 6 carbon atoms, and multiple R １ may be the same or different. r represents 4. n is an integer of 0 to 6, m is an integer of 1 to 6, and n and m are different integers.] in the absence of an organic solvent.

[0020]

[10] A compound obtained by mixing an aromatic dicarboxylic acid or a derivative thereof, an aliphatic diamine having 8 to 12 carbon atoms, and a compound represented by the formula (I):

[0021] [In formula (I), R １ ~R ５ each independently represents a hydrogen atom or an aliphatic group having 1 to 6 carbon atoms, and multiple R １ may be the same or different. r represents 4. n represents an integer of 0 to 6, m represents an integer of 1 to 6, and n and m are different integers.] in the presence of an organic solvent.

[0022]

[11] The method for producing a polyamide according to [9] or

[10] , further comprising a mechanochemical treatment step and a heat treatment step after the polymerization step.

[0023] According to the present invention, a polyamide having high heat resistance and good molding processability can be provided.

[0024] Hereinafter, one embodiment of the present invention will be described in detail, but the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention. Furthermore, when multiple upper and lower limit values ​​are specified for a specific parameter, any upper and lower limit values ​​can be combined to form a suitable numerical range.

[0025] [Polyamide] The polyamide of the present invention comprises structural units derived from an aromatic dicarboxylic acid or a derivative thereof and structural units derived from a diamine, and the diamine-derived structural units comprise structural units derived from an aliphatic diamine having 8 to 12 carbon atoms and structural units derived from a diamine represented by formula (I) (hereinafter also referred to as "asymmetric diamine (I)"). In the present invention, "structural units derived from" means "structural units derived from", and for example, "structural units derived from an aromatic dicarboxylic acid" means "structural units derived from an aromatic dicarboxylic acid".

[0026] <Diamine-derived structural units> The polyamide of the present invention contains, as diamine-derived structural units, structural units derived from an aliphatic diamine having 8 to 12 carbon atoms and structural units derived from an asymmetric diamine (I). By including at least two types of structural units in the diamine-derived structural units, crystallization of the polyamide, which is a crystalline polymer, is suppressed. As a result, the melting point of the polyamide is lowered, and moldability is improved.

[0027] (Structural Units Derived from Aliphatic Diamines Having 8 to 12 Carbon Atoms) The diamine-derived structural units include structural units derived from aliphatic diamines having 8 to 12 carbon atoms. When the diamine-derived structural units include structural units derived from aliphatic diamines having 8 to 12 carbon atoms, the molding processability of the polyamide and mechanical properties such as toughness and tensile elongation are improved. The term "aliphatic diamine" refers to a diamine in which an amino group is directly bonded to an aliphatic group, and may include an aromatic ring or other substituents as part of its structure. However, this does not include asymmetric diamines represented by formula (I).

[0028] The aliphatic diamine may be a cyclic aliphatic diamine such as 1,4-bis(aminomethyl)cyclohexane or norbornanediamine, but is preferably an acyclic aliphatic diamine. Examples of acyclic aliphatic diamines having 8 to 12 carbon atoms include linear aliphatic diamines such as 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine; and branched aliphatic diamines such as 2-methyl-1,8-octanediamine, 4-methyl-1,8-octanamine, trimethylhexanediamine, and 5-methyl-1,9-nonanediamine. From the viewpoint of heat resistance, the aliphatic diamine having 8 to 12 carbon atoms is preferably a linear aliphatic diamine having 8 to 12 carbon atoms, and more preferably a linear aliphatic diamine having 9 to 11 carbon atoms.

[0029] From the viewpoint of moldability and heat resistance, the aliphatic diamine having 8 to 12 carbon atoms is preferably an aliphatic diamine having 9 to 11 carbon atoms, more preferably an aliphatic diamine having 10 carbon atoms, and even more preferably 1,10-decanediamine.

[0030] The proportion of the structural units derived from aliphatic diamines having 8 to 12 carbon atoms can be adjusted appropriately so that the polyamide has the desired physical properties. For example, the proportion of the structural units derived from aliphatic diamines having 8 to 12 carbon atoms is preferably 60 to 99 mol%, more preferably 65 to 97 mol%, even more preferably 70 to 95 mol%, and particularly preferably 75 to 90 mol%, relative to the total molar amount (100 mol%) of the diamine-derived structural units constituting the polyamide. When this proportion is 60 mol% or more, a polyamide having a low melting point and high moldability is easily obtained. Furthermore, when this proportion is 99 mol% or less, a polyamide having high heat resistance is easily obtained.

[0031] (Constituent Units Derived from Asymmetric Diamine (I)) The diamine-derived constituent units include constituent units derived from asymmetric diamines represented by formula (I).

[0032] [In formula (I), R １ ~R ５ each independently represents a hydrogen atom or an aliphatic group having 1 to 6 carbon atoms, and multiple R１ may be the same or different. r represents 4. n represents an integer of 0 to 6, m represents an integer of 1 to 6, and n and m are different integers.

[0033] When the diamine-derived structural units contain structural units derived from the asymmetric diamine (I), the symmetry and order of the polyamide are reduced, and the melting point is lowered, thereby improving moldability.

[0034] R in formula (I) １ ~R ５ are each independently a hydrogen atom or an aliphatic group having 1 to 6 carbon atoms. Examples of the aliphatic group having 1 to 6 carbon atoms include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 2-ethylpropyl group, and an n-hexyl group; and cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group. Among these, R １ ~R ５ are each independently preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a cycloalkyl group having 5 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, still more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and particularly preferably a hydrogen atom.

[0035] In formula (I), n is an integer of 0 to 6, preferably 0 to 4, more preferably 0 to 2, even more preferably 0 or 1, and particularly preferably 0. When n is an integer of 2 to 6, a plurality of R ２ and R ３ may be the same or different from each other.

[0036] The asymmetric diamine (I) in which n is 0 can obtain the heat resistance improving effect obtained by the rigid aromatic amine structure, while also obtaining the moldability improving effect obtained by the aliphatic amine structure, thereby achieving both heat resistance and moldability at a higher level.

[0037] In formula (I), m is an integer of 1 to 6, preferably 1 to 4, more preferably 1 to 3, even more preferably 1 or 2, and particularly preferably 2. When m is 2 to 6, a plurality of R ４ and R ５ may be the same or different from each other.

[0038] Preferred combinations of n and m in formula (I) include those where n and m are different integers, n is an integer of 0 to 4, and m is an integer of 1 to 3. From the viewpoint of the mechanical properties or ease of processing of the polyamide, preferred combinations of n and m (n, m) include (n=0, m=2), (n=0, m=3), (n=0, m=4), (n=1, m=2), (n=1, m=3), (n=1, m=4), (n=2, m=1), (n=2, m=3), and (n=2, m=4). More preferred combinations of n and m (n, m) are (n=0, m=2), (n=0, m=3), (n=0, m=4), (n=1, m=2), (n=1, m=3) and (n=1, m=4), further more preferred are (n=0, m=2), (n=0, m=3) and (n=0, m=4), and particularly preferred is (n=0, m=2).

[0039] The bonding positions of the amino group and alkylamino group to the benzene ring in formula (I) when n is 0, and the bonding positions of the two alkylamino groups to the benzene ring in formula (I) when n is 1 to 6 are not particularly limited, and may be any of the ortho, meta, and para positions. In one aspect, the bonding positions are preferably para positions from the viewpoint of improving heat resistance. In one aspect, formula (I) is preferably formula (I-1).

[0040] [In formula (I-1), R １ ~R ５ , n, m are R in formula (I) １ ~R ５ , n, m]

[0041] The asymmetric diamine (I) may be a petroleum-derived asymmetric diamine or a biologically-derived (bio-derived) asymmetric diamine, but from the viewpoints of low cost production and mass production, a biologically-derived (bio-derived) asymmetric diamine is preferred.

[0042] The asymmetric diamine (I) is a diamine having a carbon number of 14 ( １４ It is preferable that the asymmetric diamines contain carbon-14. Biologically derived asymmetric diamines contain carbon-14, while petroleum-derived asymmetric diamines do not contain carbon-14. Here, "containing carbon-14" means that carbon-14 can be detected by the following measurement method, and "not containing carbon-14" means that the carbon-14 content is below the detection limit.

[0043] As a method for measuring carbon-14, for example, the carbon-14 measurement method specified in ISO16620-2, ASTM D6866, or CEN / TS16147 can be used.

[0044] The proportion of the structural units derived from the asymmetric diamine (I) can be appropriately adjusted so that the polyamide has the desired physical properties. For example, the proportion of the structural units derived from the asymmetric diamine (I) is preferably 1 to 40 mol%, more preferably 5 to 35 mol%, even more preferably 10 to 30 mol%, and particularly preferably 15 to 25 mol%, relative to the total molar amount (100 mol%) of the diamine-derived structural units constituting the polyamide. When this proportion is 1 mol% or more, the polyamide chain contains an aromatic ring structure, which tends to further improve heat resistance. Furthermore, when this proportion is 40 mol% or less, the degree of orientation of the structural units derived from the asymmetric diamine (I) in the polyamide tends to decrease the order. This tends to lower the melting point of the polyamide and further improve moldability.

[0045] The molar ratio of the structural units derived from the asymmetric diamine (I) to the structural units derived from the aliphatic diamine having 8 to 12 carbon atoms is preferably 0.1 to 0.7, more preferably 0.15 to 0.6, and even more preferably 0.2 to 0.5. When the ratio is within the above range, a polyamide having an excellent balance between heat resistance and moldability is easily obtained.

[0046] The method for producing the asymmetric diamine (I) is not particularly limited, and the asymmetric diamine may be obtained by chemically producing it using a conventional method and derived from petroleum. However, from the viewpoint of inexpensive mass production, it is preferable to obtain the asymmetric diamine derived from a biological source using a microorganism. For example, JP-A-2023-177577 can be referred to as a method for producing the asymmetric diamine (I) derived from a biological source.

[0047] (Aromatic diamine-derived structural units) The diamine-derived structural units may further include aromatic diamine-derived structural units. When aromatic diamine-derived structural units are further included, the heat resistance and mechanical properties such as rigidity of the polyamide can be further improved. Furthermore, when the diamine-derived structural units include at least three structural units, including aromatic diamine-derived structural units, the glass transition temperature can be improved while maintaining a low melting point. "Aromatic diamine" refers to a diamine in which an amino group is directly bonded to an aromatic ring, and the structure may include an aliphatic group or other substituent. This aromatic ring may be a single ring or a condensed ring, and examples include a benzene ring, a naphthalene ring, an anthracene ring, and a fluorene ring, but are not limited to these. Of these, a benzene ring is preferred.

[0048] Examples of aromatic diamines include aromatic diamines having one aromatic ring, such as p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, and 1,5-diaminonaphthalene; 2,6-diaminonaphthalene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, and bis[4-(4-aminophenoxy)phenyl]sulfone. Examples of aromatic diamines include aromatic diamines having two or more aromatic rings, such as 2,2-bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl (sometimes referred to as TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(4-amino-3-methylphenyl)fluorene, 9,9-bis(4-amino-3-chlorophenyl)fluorene, and 9,9-bis(4-amino-3-fluorophenyl)fluorene. These can be used alone or in combination of two or more.

[0049] Among these, p-phenylenediamine and m-phenylenediamine are preferred from the viewpoint of the balance between moldability, heat resistance and mechanical properties.

[0050] The proportion of the aromatic diamine-derived structural units relative to the total molar amount (100 mol%) of the diamine-derived structural units constituting the polyamide is preferably 0 to 10 mol%, more preferably 1 to 8 mol%, and even more preferably 3 to 8 mol%. When the proportion is within the above range, heat resistance can be further improved.

[0051] (Structural Units Derived from Other Diamines) The diamine-derived structural units may include the above-mentioned structural units derived from aliphatic diamines having 8 to 12 carbon atoms and structural units derived from asymmetric diamine (I), and in some cases may also include structural units derived from diamines other than structural units derived from aromatic diamines (hereinafter also referred to as "structural units derived from other diamines").

[0052] The structural units derived from other diamines are not particularly limited, and examples thereof include aliphatic diamines having 2 to 7 carbon atoms, such as ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, and 2-methyl-1,5-pentanediamine, as well as 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, m-xylylenediamine, and p-xylylenediamine.

[0053] The proportion of the constituent units derived from other diamines may be, for example, 0 to 10 mol %, more preferably 0.1 to 8 mol %, and even more preferably 0.1 to 5 mol %, relative to the total molar amount (100 mol %) of the constituent units derived from diamines constituting the polyamide.

[0054] <Structural units derived from aromatic dicarboxylic acids, etc.> The polyamide of the present invention contains structural units derived from aromatic dicarboxylic acids or derivatives thereof (hereinafter also simply referred to as "structural units derived from aromatic dicarboxylic acids, etc.). By including structural units derived from aromatic dicarboxylic acids, etc., the heat resistance of the polyamide is improved.

[0055] Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 2-methoxyterephthalic acid, naphthalenedicarboxylic acid, 4,4'-oxybisbenzoic acid, 4,4'-biphenyldicarboxylic acid, and 3,3'-biphenyldicarboxylic acid. The aromatic dicarboxylic acid may be at least one selected from the group consisting of these. These may be used alone or in combination of two or more. Examples of acid derivatives include acid halides such as acid chlorides, and acid anhydrides.

[0056] Among these, from the viewpoint of heat resistance, the aromatic dicarboxylic acid is preferably terephthalic acid, isophthalic acid, phthalic acid, or naphthalenedicarboxylic acid, more preferably terephthalic acid or isophthalic acid, and even more preferably terephthalic acid.

[0057] The proportion of the constituent units derived from aromatic dicarboxylic acids, etc., relative to the total molar amount (100 mol%) of the constituent units derived from dicarboxylic acids, etc., constituting the polyamide may be, for example, 80 to 100 mol%, more preferably 90 to 100 mol%, and even more preferably 95 to 100 mol%.

[0058] The dicarboxylic acid-derived structural units constituting the polyamide of the present invention may contain structural units derived from dicarboxylic acids other than aromatic dicarboxylic acids (hereinafter also referred to as "structural units derived from other dicarboxylic acids"). Examples of dicarboxylic acids other than aromatic dicarboxylic acids include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; and derivatives thereof.

[0059] The proportion of the constituent units derived from other dicarboxylic acids, etc. may be, for example, 0 to 20 mol %, more preferably 0.1 to 10 mol %, and even more preferably 0.1 to 5 mol %, relative to the total molar amount (100 mol %) of the constituent units derived from dicarboxylic acids, etc. that constitute the polyamide.

[0060] <Properties of Polyamide> The polyamide of the present invention has a glass transition temperature of preferably 115 to 250°C, more preferably 118 to 200°C, even more preferably 120 to 150°C, and particularly preferably 124 to 135°C. If the glass transition temperature is 115°C or higher, a polyamide having sufficiently high heat resistance will be obtained, and if it is 250°C or lower, a polyamide having good moldability will be obtained. The glass transition temperature of the polyamide means the midpoint glass transition temperature (Tmg) according to JIS K 7121. The glass transition temperature of the polyamide can be measured using a differential scanning calorimeter, for example, by the method described in the Examples.

[0061] The polyamide of the present invention has a melting point of preferably 200 to 390°C, more preferably 220 to 350°C, even more preferably 250 to 320°C, and particularly preferably 270 to 300°C. A melting point of 390°C or lower will result in a polyamide with good moldability, while a melting point of 200°C or higher will result in a polyamide with sufficiently high heat resistance. The melting point of the polyamide means the top of the endothermic peak in JIS K 7121. The melting point of the polyamide can be measured using a differential scanning calorimeter, for example, by the method described in the Examples.

[0062] The thermal decomposition temperature of the polyamide of the present invention is preferably 400 to 500°C, more preferably 420 to 470°C, and even more preferably 430 to 455°C. Furthermore, the thermal decomposition temperature of the polyamide of the present invention is higher than the melting point, and the difference between the thermal decomposition temperature and the melting point is preferably 100 to 200°C, more preferably 130 to 200°C, and even more preferably 150 to 200°C. The higher the thermal decomposition temperature is above the melting point, the wider the range in which the molding temperature can be set, resulting in improved molding processability. The thermal decomposition temperature of the polyamide refers to the onset temperature T1 in JIS K 7120. The thermal decomposition temperature of the polyamide can be measured using a thermogravimetric and differential thermal analyzer, for example, by the method described in the Examples.

[0063] The relative viscosity of the polyamide of the present invention may be, for example, 1.2 to 6, preferably 1.5 to 5.8, more preferably 2 to 5.5, even more preferably 2.5 to 5.3, and particularly preferably 3 to 5. A high relative viscosity value tends to result in a high molecular weight, but if the relative viscosity is too high, the resin fluidity tends to decrease, resulting in poor processability. A low relative viscosity value also tends to result in a low molecular weight, but if the relative viscosity is too low, the resin fluidity is high and easy to process, but the mechanical strength tends to decrease. When the relative viscosity is above the lower limit, a polyamide with good mechanical properties such as tensile strength and toughness can be obtained. When the relative viscosity is below the upper limit, the molding processability is improved. The relative viscosity can be measured by a method in accordance with JIS K 6920-2, for example, by the method described in the Examples.

[0064] The polyamide of the present invention, by employing an asymmetric diamine (I) and an aliphatic diamine having 8 to 12 carbon atoms as the diamine components, becomes a resin excellent in processability, heat resistance, and mechanical properties. Specifically, the polyamide of the present invention has a melting point that is easy to process, and further tends to have a higher glass transition temperature, which indicates the heat resistance of a molded body or product, compared to polyamides employing only either the asymmetric diamine (I) or an aliphatic diamine having 8 to 12 carbon atoms as the diamine component. Furthermore, the polyamide of the present invention tends to have a larger temperature difference between the melting point and the thermal decomposition temperature, compared to polyamides employing only either the asymmetric diamine (I) or an aliphatic diamine having 8 to 12 carbon atoms as the diamine component. This larger temperature difference allows processing such as melt kneading at lower temperatures, and the polyamide tends not to thermally decompose even at high processing temperatures, thereby widening the temperature range in which the polyamide can be processed, resulting in superior processability.

[0065] On the other hand, polyamides using only asymmetric diamines (I) as the diamine component tend to have a high melting point due in part to their rigid structure. In this case, processing such as melt-kneading is not possible unless the temperature is high, which tends to be disadvantageous in terms of safety, operational efficiency, and energy efficiency. Furthermore, if only aliphatic diamines having 8 to 12 carbon atoms are used as the diamine component, the melting point is not too high, but the heat resistance of the polyamide and molded articles containing it tends to be reduced.

[0066] <Uses of Polyamide> The polyamide of the present invention has excellent heat resistance, mechanical strength, and processability. The polyamide of the present invention can be used in a wide range of applications, from substitutes for super engineering plastics to substitutes for commonly used plastics. Specific examples include automobile parts, electrical and electronic parts, sliding parts, tube-related parts, household goods, metal coating agents, civil engineering and construction supplies, computer and related equipment parts, optical equipment parts, information and communication equipment parts, and precision equipment parts.

[0067] [Method for Producing Polyamide] The method for producing the polyamide of the present invention is not particularly limited, and the polyamide can be produced, for example, by a method including a polymerization step of polymerizing an aromatic dicarboxylic acid or a derivative thereof, an aliphatic diamine having 8 to 12 carbon atoms, an asymmetric diamine (I), and optionally an aromatic diamine, another diamine, and a dicarboxylic acid other than the aromatic dicarboxylic acid or a derivative thereof.

[0068] The raw material monomers such as aromatic dicarboxylic acid or derivatives thereof, aliphatic diamines having 8 to 12 carbon atoms, asymmetric diamine (I), aromatic diamines, etc. are the same as those, including preferred forms, described in the respective sections relating to the structural units that the polyamide of the present invention may contain.

[0069] In the polymerization step, the amounts of raw material monomers such as aromatic dicarboxylic acid or its derivative, aliphatic diamine having 8 to 12 carbon atoms, asymmetric diamine (I), aromatic diamine, etc., used can be appropriately selected depending on the ratio of each structural unit of the desired polyamide. The total amount of diamine used is preferably 0.96 to 1.04, more preferably 0.98 to 1.02, and even more preferably 0.99 to 1.01, per mole of the total amount of aromatic dicarboxylic acid or its derivative used.

[0070] The polymerization temperature is not particularly limited and is, for example, 10 to 350°C, preferably 50 to 300°C, and more preferably 100 to 250°C. The polymerization time is also not particularly limited and is, for example, about 30 minutes to 10 hours, and preferably about 1 to 8 hours. If necessary, the polymerization may be carried out with stirring in an inert atmosphere or under reduced pressure.

[0071] The polymerization step may be a step in which polymerization is carried out in the presence of an organic solvent, or a step in which polymerization is carried out in the absence of an organic solvent.

[0072] The organic solvent is not particularly limited as long as it does not affect the reaction, and examples thereof include alcohol-based solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, 1-methoxy-2-propanol, 2-butoxyethanol, and propylene glycol monomethyl ether; ester-based solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone (hereinafter sometimes referred to as GBL), γ-valerolactone, propylene glycol methyl ether acetate, and ethyl lactate; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, and 2-heptanone; nitrile-based solvents such as acetonitrile; ether-based solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; amide-based solvents such as N,N-dimethylacetamide (sometimes referred to as DMAc) and N,N-dimethylformamide (sometimes referred to as DMF); sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide, and sulfolane; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and combinations thereof.

[0073] Polymerization in the absence of an organic solvent means polymerization in the presence of a solvent other than an organic solvent such as water, or polymerization without using a solvent, and polymerization in the presence of water or in the absence of a solvent is preferred.

[0074] In the polymerization step, a terminal blocking agent may be used in addition to the raw material monomers. Examples of terminal blocking agents include monofunctional acid anhydride compounds, monofunctional amine compounds, monofunctional carboxylic acid compounds or halides thereof, monofunctional alcohol compounds, monofunctional phenol compounds, monofunctional isocyanate compounds, and monofunctional epoxy compounds. Preferred terminal blocking agents are monofunctional acid anhydride compounds, monofunctional amine compounds, monofunctional carboxylic acid compounds or acid halides thereof, monofunctional alcohol compounds, and monofunctional phenol compounds, with monofunctional carboxylic acid compounds or acid halides thereof being more preferred. Examples of monofunctional carboxylic acids include acetic acid, propionic acid, octanoic acid, cyclohexanecarboxylic acid, toluic acid, phenylacetic acid, p-methoxyphenylacetic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, and p-tert-butylbenzoic acid. These may be used alone or in combination of two or more.

[0075] The end-capping agent can be used in an appropriate amount, taking into consideration the adjustment of the degree of polymerization of the polyamide, etc. The amount of the end-capping agent added is preferably, for example, 5 mol % or less based on the total moles of the aromatic dicarboxylic acid and diamine used in the production of the polyamide.

[0076] In the polymerization step, a polymerization catalyst may be used in addition to the raw material monomers. Examples of the polymerization catalyst include paratoluenesulfonic acid, dimethyl sulfate, diethyl sulfate, sulfuric acid, hydrochloric acid, oxalic acid, acetic acid, phosphoric acid, phosphorous acid, hypophosphorous acid, or salts thereof, sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, pyridine, ammonia, triethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylethanolamine, aminoethanolamine, N-methyl-N,N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, 3-methoxypropylamine, monoethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine, 1-methylimidazole, 2-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-ethyl- Imidazole compounds such as 2-phenylimidazole and 1-cyanoethyl-2-ethyl-4-methylimidazole; Lewis acid complexes of boron halides such as boron trifluoride-piperidine complex, boron trifluoride-monoethylamine complex, boron trifluoride-triethanolamine complex, and boron trichloride-octylamine complex; dicyandiamide derivatives; onium salts such as ammonium salts and phosphonium salts; N,N-dimethyl-N'-(3-chloro-4-methylphenyl)urea, N,N-dimethyl-N'- quaternary ammonium salts such as (4-chlorophenyl)urea, N,N-dimethyl-N'-(3,4-dichlorophenyl)urea, N,N-dimethyl-N'-(3,4-dichloromethylphenyl)urea, 2,4-(N',N'-dimethylureido)toluene, 1,4-bis(N',N'-dimethylureido)benzene, tri-n-butylbenzylammonium halide, tetra-n-butylammonium halide, trimethylbenzylammonium halide, and triethylbenzylammonium halide;and quaternary phosphonium salts such as tri-n-butylbenzylphosphonium halide, tetra-n-butylphosphonium halide, trimethylbenzylphosphonium halide, and triethylbenzylphosphonium halide; oxides and acetates of magnesium, manganese, zinc, calcium, lithium, titanium, antimony, germanium, and the like;

[0077] The polymerization catalyst can be used in an appropriate amount taking into consideration the adjustment of the polymerization degree of the polyamide, etc. The amount of the polymerization catalyst added is preferably, for example, 2 mol % or less based on the total moles of the aromatic dicarboxylic acid and diamine used in the production of the polyamide.

[0078] The polyamide of the present invention may be produced by a method further including a heat treatment step (hereinafter also referred to as the "first heat treatment step") after the polymerization step. The first heat treatment step is a step in which additional heating is performed after the polymerization step. By performing additional heating in the first heat treatment step, the molecular weight of the resulting polyamide is increased and mechanical properties such as tensile strength are improved.

[0079] The heating temperature in the first heat treatment step is preferably 80 to 400°C. From the viewpoint of efficiently increasing the molecular weight of the polyamide, the lower limit of the heating temperature is more preferably 100°C or higher, and even more preferably 200°C or higher. Furthermore, from the viewpoint of suppressing thermal decomposition of the polyamide due to the heating temperature in this step, the upper limit of the heating temperature is more preferably 350°C or lower, and even more preferably 300°C or lower. In one embodiment, the heating temperature range is preferably 100 to 350°C, more preferably 200 to 300°C. The heating time in the first heat treatment step can be appropriately adjusted taking into account the composition ratio of the raw material monomers to be polymerized or the desired degree of polymerization. The heating time in the first heat treatment step is, for example, preferably 30 minutes to 24 hours, more preferably 1 to 20 hours, and even more preferably 2 to 16 hours. Heating may be performed in a stream of inert gas such as nitrogen, or under pressure or reduced pressure. Furthermore, heating may be performed while standing or with stirring.

[0080] The heat treatment in the first heat treatment step may be carried out in one stage or in two or more stages. When the heat treatment is carried out in two or more stages, the heating temperature and heating time in each stage may be different from each other. For example, the mixture may be heated at 80 to 120°C for 30 minutes to 3 hours, and then further heated at 200 to 300°C for 1 to 20 hours. Furthermore, for example, the mixture may be heated with stirring, and then left to stand under a stream of inert gas such as nitrogen for further heating.

[0081] The method for producing a polyamide of the present invention may further include a pulverization step of pulverizing or crushing the polymer. The pulverization step can be carried out after the polymerization step, and is preferably carried out after the polymerization step and before the first heat treatment step. The method for pulverizing or crushing the polymer is not particularly limited, and various known methods such as using a pulverizer or freeze-pulverization can be used.

[0082] When the polyamide production method includes a pulverization step, the resulting polyamide tends to have a higher molecular weight.This is thought to be due to the fact that, even if unreacted monomers exist inside the polymer after the polymerization step, for example, due to the pulverization or crushing of the polymer, the unreacted monomers existing inside the polymer are exposed to a high temperature environment in the subsequent first heat treatment step, resulting in polymerization.Therefore, in the polyamide production method of the present invention, either the pulverization step or the first heat treatment step may be carried out first, but it is preferred to carry out the pulverization step after the polymerization step, and then heat the pulverized material in the first heat treatment step.

[0083] In the present invention, in order to increase the molecular weight of the resulting polyamide, it is preferable to repeatedly perform the desired steps, such as the pulverization step and the first heat treatment step, among the polymerization step, pulverization step, and first heat treatment step of the above-mentioned production method. In one embodiment, the polyamide may be produced by performing the pulverization step and the first heat treatment step 1 to 10 times, preferably 2 to 5 times, after the polymerization step. By repeating the pulverization step and the first heat treatment step multiple times, for example, two or more times, after the polymerization step, the amount of low-molecular-weight components, such as unreacted monomers, that may be present in the resulting polyamide can be reduced. If the amount of low-molecular-weight components, such as unreacted monomers, that may be present in the polyamide is large, the melting point and thermal decomposition temperature of the polyamide may decrease, causing the polyamide to decompose during molding processing, or the reaction of low-molecular-weight components, such as unreacted monomers, may progress in the polyamide during molding processing, resulting in changes in the molding processability of the polyamide. By reducing the amount of low-molecular-weight components, such as unreacted monomers, that may be present in the polyamide, changes in molding processability due to decomposition or reaction progress, and variations in the melting point and thermal decomposition temperature are less likely to occur. Therefore, by repeating the pulverization step and the first heat treatment step multiple times, for example, two or more times, after the polymerization step, it is possible to suppress changes in molding processability and variations in the melting point and thermal decomposition temperature, and it tends to be possible to obtain a polyamide having consistent molding processability.

[0084] The polyamide of the present invention may be produced by a method further comprising a mechanochemical treatment step and a second heat treatment step after the polymerization step, or after the polymerization step, the pulverization step, and the first heat treatment step, which can further improve the mechanical properties of the polyamide.

[0085] The mechanochemical treatment step is a step of mechanochemically treating the polymer or reaction product obtained in the polymerization step. By performing the mechanochemical treatment step, particles of the polymer collide violently with each other in the mechanochemical treatment device. As a result, the molecular weight and relative viscosity of the polymer obtained in the polymerization step increase, and the mechanical properties such as tensile strength of the resulting polyamide are further improved.

[0086] In the present invention, the mechanochemical treatment is a process of applying mechanical energy such as strong compressive force, shear force, impact force, or grinding force to the polymer solid obtained in the polymerization process to activate the solid surface.

[0087] Examples of equipment for carrying out mechanochemical treatment include wheel-type kneaders such as edge runner mills, Stots mills, wet pan mills, Conner mills, and ring muller mills; ball-type kneaders such as planetary ball mills, tumbling ball mills, centrifugal ball mills, and vibrating ball mills; blade-type kneaders such as Henschel mixers, planetary mixers, and Nauta mixers; roll-type kneaders such as extruders; jet-type crushers such as swirling flow jet mills and fluidized bed jet mills; impact crushers such as hammer mills, pin mills, screen mills, turbo mills, and centrifugal classification mills; roller mills such as ring roller mills and centrifugal roller mills; stirring mills such as stirred tank mills, flow pipe mills, and annular mills; and surface modification equipment such as Hosokawa Micron's Nobilta and Mechanofusion, and Nara Machinery Manufacturing's Hybridization System and Miraro.

[0088] The mechanochemical treatment may be a dry treatment or a wet treatment, but a dry treatment is preferred. The mechanochemical treatment may be carried out in one stage or in multiple stages of two or more stages.

[0089] The second heat treatment step is a step of additionally heating the polyamide after the mechanochemical treatment step. By applying additional heat in the second heat treatment step, the molecular weight and relative viscosity of the resulting polyamide are further increased, and mechanical properties such as tensile strength are further improved.

[0090] The heating temperature in the second heat treatment step is preferably 150 to 400° C., more preferably 200 to 300° C., and even more preferably 230 to 280° C. A heating temperature of 200° C. or higher can efficiently increase the relative viscosity and molecular weight of the polyamide, while a heating temperature of 300° C. or lower can suppress thermal decomposition of the polyamide.

[0091] The heating time in the second heat treatment step is preferably 10 minutes to 12 hours, more preferably 30 minutes to 8 hours, and even more preferably 1 to 5 hours. Heating may be carried out in a stream of an inert gas such as nitrogen, or under pressure or reduced pressure. Heating may be carried out while the mixture is left standing or while stirring.

[0092] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples.

[0093] [Measurement Method] (1) Relative Viscosity of Polyamide The relative viscosity of polyamide was measured in accordance with JIS K 6920-2 using 96% by mass sulfuric acid as a solvent at a concentration of 1 g / dL and 25° C. The test specimen was conditioned as described in "4.2 Dry State."

[0094] (2) Glass Transition Temperature and Melting Point of Polyamide Using a differential scanning calorimeter ("Discovery DSC250" manufactured by TA Instruments), the temperature was raised to 370°C at a heating rate of 10°C / min, then held at 370°C for 5 minutes, then lowered to 25°C at a heating rate of 10°C / min, held at 25°C for 5 minutes, and then raised again at a heating rate of 10°C / min. The midpoint glass transition temperature (Tmg) measured according to JIS K 7121 was taken as the glass transition temperature (Tg), and the top of the endothermic peak was taken as the melting point (Tm).

[0095] (3) Thermal decomposition temperature of polyamide Using a thermogravimetric and differential thermal analyzer (manufactured by Bruker, "TG-DTA 2010S"), the temperature was held at 25°C for 5 minutes, and then heated to 500°C at a heating rate of 10°C / min. The initiation temperature T1 in accordance with JIS K 7120 was measured and taken as the thermal decomposition temperature. All measurements were carried out under a nitrogen atmosphere.

[0096] Example 1 [Step (i)] 1,10-decanediamine (137 parts by mass), an aliphatic diamine, and 2-(4-aminophenyl)ethylamine (27 parts by mass), an asymmetric diamine (I), powdered terephthalic acid (166 parts by mass) as a dicarboxylic acid component, benzoic acid (2.4 parts by mass) as an end-capping agent, and sodium hypophosphite monohydrate (0.2 parts by mass) as a polymerization catalyst were placed in an autoclave and heated to 100°C. After heating, stirring was initiated using an anchor-type stirring blade, and heating was continued for 1 hour. The molar ratio of the raw material monomers was diamine component:terephthalic acid = 50:50. After heating at 100°C for 1 hour, the temperature was increased to 230°C, and then the mixture was heated at 230°C for 3 hours. The water vapor generated by the reaction was depressurized, and the resulting reaction product was removed. The aliphatic diamine, dicarboxylic acid component, and end-capping agent used were all commercially available products sold by Tokyo Chemical Industry Co., Ltd. The polymerization catalyst used was a commercially available product sold by Sigma-Aldrich. [Step (ii)] The reaction product obtained in step (i) was pulverized and then placed back into the autoclave. After heating to 100°C, stirring was started using an anchor-type stirring blade and heating for 1 hour. After heating at 100°C for 1 hour, the temperature was increased to 230°C, and then heated at 230°C for 1.5 hours, and then further increased to 240°C for 1.5 hours. After releasing the water vapor generated by the reaction, the resulting reaction product was removed. [Step (iii)] The reaction product obtained in step (ii) was pulverized and then heated at 230°C for 5 hours under normal pressure nitrogen gas flow to polymerize and obtain polyamide (P-1).

[0097] Example 2 [Step (i)] 1,10-decanediamine (1,142 parts by mass), an aliphatic diamine, and 2-(4-aminophenyl)ethylamine (386 parts by mass), an asymmetric diamine (I), powdered terephthalic acid (1,562 parts by mass) as a dicarboxylic acid component, sodium hypophosphite monohydrate (2 parts by mass) as a polymerization catalyst, and water (2,843 parts by mass) were placed in an autoclave and heated to 100°C. After stirring using an anchor-type stirring blade, the mixture was heated for 1 hour. The molar ratio of the raw material monomers was diamine component:terephthalic acid = 50:50. After heating at 100°C for 1 hour, the mixture was heated to 230°C and then heated at 230°C for 6 hours. The charged water and the water vapor generated by the reaction were released, and the resulting reaction product was removed. [Step (ii)] The reaction product obtained in step (i) was pulverized and then placed back into the autoclave. Stirring was started using an anchor-type stirring blade, the temperature was raised to 240°C, and the mixture was heated at 240°C for 4 hours. After the water vapor generated by the reaction was released, the reaction product was removed. [Step (iii)] The reaction product obtained in step (ii) was pulverized and then placed back into the autoclave. Stirring was started using an anchor-type stirring blade, the temperature was raised to 250°C, and the mixture was heated at 250°C for 4 hours. After the water vapor generated by the reaction was released, the reaction product was removed. [Step (iv)] The reaction product obtained in step (iii) was pulverized and then placed back into the autoclave. Stirring was started using an anchor-type stirring blade, the temperature was raised to 250°C, and the mixture was heated at 250°C for 4 hours. After the water vapor generated by the reaction was released, the reaction product was removed. [Step (v)] The reaction product obtained in step (iv) was pulverized and then heated at 250° C. for 6 hours under normal pressure in a nitrogen stream to polymerize it, thereby obtaining polyamide (P-2).

[0098] Comparative Example 1 [Step (i)] 1,10-decanediamine (1620 parts by mass), an aliphatic diamine, as the diamine component, powdered terephthalic acid (1562 parts by mass) as the dicarboxylic acid component, benzoic acid (23 parts by mass) as an end-blocking agent, and sodium hypophosphite monohydrate (2 parts by mass) as a polymerization catalyst were placed in an autoclave and heated to 100°C. After heating, stirring was initiated using an anchor-type stirring blade, and heating was continued for 1 hour. The molar ratio of the raw material monomers was diamine component:terephthalic acid = 50:50. After heating at 100°C for 1 hour, the temperature was increased to 230°C, and then heated at 230°C for 3 hours. The water vapor generated by the reaction was released, and the resulting reaction product was removed. [Step (ii)] The reaction product obtained in step (i) was pulverized and then placed back in the autoclave. Stirring was initiated using an anchor-type stirring blade, the temperature was increased to 230°C, and heating was continued at 230°C for 3 hours. The water vapor generated by the reaction was released, and the resulting reaction product was then taken out. [Step (iii)] The reaction product obtained in step (ii) was pulverized and then heated at 230°C for 5 hours under a nitrogen stream at normal pressure to polymerize the product, thereby obtaining polyamide (P-3).

[0099] Comparative Example 2 [Step (i)] 2-(4-aminophenyl)ethylamine (136 parts by mass), which is the asymmetric diamine (I) as the diamine component, powdered terephthalic acid (166 parts by mass) as the dicarboxylic acid component, benzoic acid (2.4 parts by mass) as an end-blocking agent, and sodium hypophosphite monohydrate (0.2 parts by mass) as the polymerization catalyst were placed in an autoclave and heated to 100°C. After that, stirring was initiated using an anchor-type stirring blade and heating was continued for 1 hour. The molar ratio of the raw material monomers was diamine component:terephthalic acid = 50:50. After heating at 100°C for 1 hour, the temperature was increased to 240°C and then heated at 240°C for 3 hours. The water vapor generated by the reaction was released, and the resulting reaction product was removed. [Step (ii)] The reaction product obtained in step (i) was pulverized and then placed back in the autoclave. It was heated to 100°C, stirring was initiated using an anchor-type stirring blade, and heating was continued for 1 hour. After heating at 100°C for 1 hour, the temperature was increased to 240°C and then heated at 240°C for 3 hours. After the water vapor generated by the reaction was released, the resulting reaction product was removed. [Step (iii)] The reaction product obtained in step (ii) was pulverized and then heated at 250°C for 5 hours under normal pressure in a nitrogen stream to polymerize, thereby obtaining polyamide (P-4).

[0100] The resin compositions (mol %) and characteristic values ​​of the polyamides (P-1) to (P-4) are shown in Table 1. The numerical values ​​for the end-capping agent in Table 1 are the molar ratios (mol %) relative to the total amount of the diamine component and dicarboxylic acid component, 100 mol %.

[0101]

[0102] The polyamide (P-1) obtained in Example 1 and the polyamide (P-2) obtained in Example 2 had higher glass transition temperatures than the polyamide (P-3) obtained in Comparative Example 1, and had melting points as low as the polyamide (P-3) obtained in Comparative Example 1 compared to the polyamide (P-4) obtained in Comparative Example 2, confirming that they had both moldability and heat resistance.

[0103] The polyamide obtained in Comparative Example 2, which used only the asymmetric diamine (I) as the diamine component, had the highest melting point and required high temperatures during resin processing to be melt-kneaded, making it difficult to process in terms of operation and energy. In contrast, the polyamides obtained in Examples 1 and 2 and Comparative Example 1 had lower melting points than Comparative Example 2, and were therefore superior to Comparative Example 2 in terms of processability.

[0104] Comparing these examples, the polyamides obtained in Examples 1 and 2 have higher glass transition temperatures than Comparative Example 1, which does not contain the asymmetric diamine (I) in the diamine component. These results demonstrate that the polyamides obtained in Examples 1 and 2 have excellent processability and excellent heat resistance for products such as molded articles containing them.

[0105] Furthermore, when the temperature difference between the melting point and the thermal decomposition temperature is large, the temperature range in which the resin can be processed is wide, and therefore, it is superior in terms of processing. Comparing Examples 1 and 2 with Comparative Examples 1 and 2, it is found that Examples 1 and 2 have a larger temperature difference between the melting point and the thermal decomposition temperature than Comparative Examples 1 and 2, and are therefore superior in terms of processing.

[0106] Example 3 [Step (A)] 20 parts by mass of the polyamide (P-2) obtained in Example 2 was placed in a hybridization system (NHS-0) manufactured by Nara Machinery Manufacturing Co., Ltd., and treated for 10 minutes under nitrogen at a peripheral speed of 100 m / s. The treated contents were then removed to obtain polyamide (P-5). [Step (B)] The polyamide (P-5) obtained in step (A) was heated at 250°C for 6 hours under a nitrogen stream at normal pressure to obtain polyamide (P-6). The relative viscosity of polyamide (P-6) was 3.14.

[0107] Comparative Example 3 [Step (B)] Polyamide (P-7) was obtained by heating 20 parts by mass of polyamide (P-2) obtained in Example 2 at 250°C for 6 hours under a nitrogen gas flow at normal pressure. The relative viscosity of polyamide (P-7) was 2.34.

[0108] Comparative Example 4 [Step (A)] 20 parts by mass of the polyamide (P-2) obtained in Example 2 was placed in a hybridization system (NHS-0) manufactured by Nara Machinery Manufacturing Co., Ltd., and treated for 10 minutes under nitrogen at a peripheral speed of 100 m / s. The treated contents were then removed to obtain polyamide (P-8). The relative viscosity of polyamide (P-8) was 2.34.

[0109] It can be seen that the polyamide obtained in Example 3, in which both the mechanochemical treatment step (A) and the second heat treatment step (B) were performed on the polyamide after polymerization, had a higher relative viscosity than the polyamide obtained in the case in which neither step (A) nor (B) was performed on the polyamide after polymerization (Example 2), or in the case in which only one of the steps was performed (Comparative Examples 3 and 4). From these results, it is predicted that by performing both the mechanochemical treatment step and the second heat treatment step, the relative viscosity of the polyamide was increased, and therefore the polyamide was able to have a higher molecular weight.

[0110] The polyamide obtained in Example 3 is expected to have a higher molecular weight because it has a higher relative viscosity than the polyamides obtained in Example 2 and Comparative Examples 3 and 4. Therefore, the polyamide obtained in Example 3 tends to have improved mechanical strength compared to the polyamides obtained in Comparative Examples 3 and 4, which were subjected to only the mechanochemical treatment step or the second heat treatment step, while maintaining processability equivalent to that of Example 2. Therefore, when both the mechanochemical treatment and the second heat treatment step are employed in the polyamide production method, a polyamide suitable for applications requiring higher strength can be obtained.

Claims

1. A composition comprising a structural unit derived from an aromatic dicarboxylic acid or a derivative thereof and a structural unit derived from a diamine, wherein the structural unit derived from the diamine is a structural unit derived from an aliphatic diamine having 8 to 12 carbon atoms and a structural unit represented by the formula (I): [In formula (I), R １ ~R ５ each independently represents a hydrogen atom or an aliphatic group having 1 to 6 carbon atoms, and multiple R １ may be the same or different. r represents 4. n represents an integer of 0 to 6, m represents an integer of 1 to 6, and n and m are different integers.] 2. The polyamide of claim 1, wherein the aliphatic diamine is a linear aliphatic diamine.

3. The polyamide according to claim 1 or 2, wherein the diamine-derived structural units further include aromatic diamine-derived structural units.

4. The polyamide according to claim 1 or 2, wherein n is 0 in formula (I).

5. The polyamide according to claim 1 or 2, wherein the aromatic dicarboxylic acid is terephthalic acid, isophthalic acid, or phthalic acid.

6. The polyamide according to claim 1 or 2, wherein the aliphatic diamine is 1,10-decanediamine.

7. The polyamide according to claim 1 or 2, wherein the proportion of the diamine-derived structural units represented by formula (I) is 30 mol % or less relative to the total molar amount of diamine-derived structural units constituting the polyamide.

8. The polyamide according to claim 1 or 2, wherein the polyamide has a glass transition temperature of 115°C or higher and a melting point of 390°C or lower.

9. A compound obtained by mixing an aromatic dicarboxylic acid or a derivative thereof, an aliphatic diamine having 8 to 12 carbon atoms, and a compound represented by the formula (I): [In formula (I), R １ ~R ５ each independently represents a hydrogen atom or an aliphatic group having 1 to 6 carbon atoms, and multiple R １ may be the same or different. r represents 4. n represents an integer of 0 to 6, m represents an integer of 1 to 6, and n and m are different integers.] in the absence of an organic solvent.

10. A compound obtained by mixing an aromatic dicarboxylic acid or a derivative thereof, an aliphatic diamine having 8 to 12 carbon atoms, and a compound represented by formula (I): [In formula (I), R １ ~R ５ each independently represents a hydrogen atom or an aliphatic group having 1 to 6 carbon atoms, and multiple R １ may be the same or different. r represents 4. n represents an integer of 0 to 6, m represents an integer of 1 to 6, and n and m are different integers.] in the presence of an organic solvent.

11. The method for producing a polyamide according to claim 9 or 10, further comprising a mechanochemical treatment step and a heat treatment step after the polymerization step.

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