Polyamide resin, resin composition, molded article, method for producing polyamide resin, and method for producing molded article

Abstract

The present invention provides a polyamide resin, a resin composition, a molded article, a method for producing a polyamide resin, and a method for producing a molded article. Provided is a polyamide resin which is a copolymer of a diamine, dicarboxylic acid, and trimesic acid, wherein not less than 50 mol% of the diamine is a xylylenediamine, and the trimesic acid is 0.01-5 mol% with respect to 100 mol% of the total of the diamine, the dicarboxylic acid and the trimesic acid.

Description

Polyamide resin, resin composition, molded body, method for producing polyamide resin, and method for producing molded body

[0001] The present invention relates to a polyamide resin, a resin composition, a molded article, a method for producing a polyamide resin, and a method for producing a molded article.

[0002] Polyamide resins are widely used as various industrial materials due to their excellent processability, durability, heat resistance, gas barrier properties, chemical resistance, and the like. Aliphatic polyamide resins, such as polyamide 6 and polyamide 66, have long been used as such polyamide resins. Furthermore, aromatic polyamide resins, which use aromatic dicarboxylic acids and / or aromatic diamines as raw materials for the polyamide resin, have also come into use. For example, Patent Document 1 discloses a polyamide resin composition containing a polyamide resin (A) composed of diamine structural units containing 50 mol % or more of structural units derived from xylylenediamine and dicarboxylic acid structural units, and trimesic acid, wherein the content of trimesic acid per 100 parts by mass of the polyamide resin (A) is 0.001 to 2 parts by mass.

[0003] JP 2015-117316 A

[0004] The resin composition described in Patent Document 1 is a polyamide resin synthesized from metaxylylenediamine and sebacic acid, and can provide a molded article with excellent toughness while maintaining the inherent tensile modulus of elasticity. However, such a resin composition has a low melt viscosity, and a different polyamide resin or resin composition suitable for extrusion molding or the like is needed. The present invention aims to solve this problem by providing a polyamide resin with a high melt viscosity, as well as a resin composition, a molded article, a method for producing a polyamide resin, and a method for producing a molded article.

[0005] In light of the above-mentioned problems, the present inventors conducted research and found that the above-mentioned problems could be solved by using a copolymer of a diamine such as xylylenediamine, a dicarboxylic acid, and trimesic acid. Specifically, the above-mentioned problems were solved by the following means. <1> A polyamide resin that is a copolymer of a diamine, a dicarboxylic acid, and trimesic acid, wherein 50 mol% or more of the diamine is xylylenediamine, and the trimesic acid accounts for 0.01 to 5 mol% of the trimesic acid relative to 100 mol% of the total of the diamine, dicarboxylic acid, and trimesic acid. <2> The polyamide resin according to <1>, wherein 50 mol% or more of the dicarboxylic acid is an α,ω-linear aliphatic dicarboxylic acid and / or an aromatic dicarboxylic acid having 4 to 20 carbon atoms. <3> The polyamide resin according to <1>, wherein 5 to 100 mol% of the dicarboxylic acid is an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and 95 to 0 mol% is isophthalic acid. <4> The polyamide resin according to <1>, wherein 60 to 40 mol % of the dicarboxylic acids are α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms and 40 to 60 mol % are isophthalic acid. <5> The polyamide resin according to <1>, wherein 97 to 80 mol % of the dicarboxylic acids are α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms and 3 to 20 mol % are isophthalic acid. <6> The polyamide resin according to any one of <1> to <5>, wherein 5 to 100 mol % of the dicarboxylic acids are one or more of adipic acid, sebacic acid, and dodecanedioic acid. <7> The polyamide resin is melted at a temperature of 250°C, a shear rate of 121.6 s －１The polyamide resin according to any one of <1> to <6>, having a melt viscosity of 510 Pa s or more, as measured according to the method described above. <8> A resin composition comprising the polyamide resin according to any one of <1> to <7>. <9> A molded article formed from the resin composition comprising the polyamide resin according to any one of <1> to <7>. <10> The molded article according to <9>, which is an extrusion molded article. <11> The molded article according to <9> or <10>, which is a film, fiber, or foam. <12> A method for producing a polyamide resin, comprising copolymerizing a diamine, a dicarboxylic acid, and trimesic acid, wherein 50 mol % or more of the diamine is xylylenediamine, and the trimesic acid accounts for 0.01 to 5 mol % relative to 100 mol % in total of the diamine, dicarboxylic acid, and trimesic acid. <13> A method for producing a polyamide resin, wherein the polyamide resin is the polyamide resin according to any one of <1> to <7>. <14> A method for producing a molded article, comprising extrusion molding the resin composition according to <8>.

[0006] According to the present invention, it is possible to provide a polyamide resin having a high melt viscosity, a resin composition, a molded article, a method for producing a polyamide resin, and a method for producing a molded article.

[0007] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the following present embodiment is an example for explaining the present invention, and the present invention is not limited to only this embodiment. Note that in this specification, the word "to" is used to mean that the numerical values ​​written before and after it are included as lower and upper limits. In this specification, various physical property values ​​and characteristic values ​​are those at 23°C unless otherwise specified. When the measurement methods etc. described in the standards shown in this specification vary depending on the fiscal year, they are based on the standards as of January 1, 2023, unless otherwise specified.

[0008] The polyamide resin of this embodiment is a copolymer of diamine, dicarboxylic acid, and trimesic acid, characterized in that 50 mol% or more of the diamine is xylylenediamine, and the trimesic acid is 0.01 to 5 mol% relative to the total of 100 mol% of the diamine, dicarboxylic acid, and trimesic acid. This configuration makes it possible to provide a polyamide resin with high melt viscosity. The inventors conducted research on Patent Document 1 and found that, although Patent Document 1 involves melt-kneading trimesic acid with a specific polyamide resin, this method, as shown in the examples of Patent Document 1, does not react with the polyamide resin. In resin compositions containing such polyamide resin and trimesic acid, trimesic acid functions as a plasticizer, making them excellent for injection molding, but not necessarily suitable for extrusion molding, which requires high melt viscosity and melt tension. In this embodiment, it is believed that the high melt tension is achieved by copolymerizing diamine, dicarboxylic acid, and trimesic acid and incorporating trimesic acid into the polyamide chain. That is, in this embodiment, because diamine, dicarboxylic acid, and trimesic acid are copolymerized, trimesic acid is usually incorporated into the polyamide chain. Furthermore, trimesic acid has three carboxylic acid groups, but these carboxylic acid groups are directly bonded to benzene rings, so their reactivity is not necessarily high. Therefore, when attempting to synthesize a polyamide resin by polycondensation of diamine, dicarboxylic acid, and trimesic acid, it is presumed that two of the three carboxylic acid groups in trimesic acid usually react with the diamine, and the remaining carboxylic acid remains as a carboxylic acid group in the polyamide chain. In this embodiment, it is presumed that the carboxylic acid groups remaining in the polyamide chain interact with each other, reducing the fluidity of the polyamide resin and increasing its melt viscosity. As a result, it is presumed that the melt tension of the resulting polyamide resin is also improved.

[0009] In the polyamide resin of this embodiment, 50 mol% or more of the diamine is xylylenediamine, preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 94 mol% or more, and may be 96 mol% or more, 98 mol%, 99 mol% or more, or even 100 mol%. By making it equal to or greater than the lower limit, the barrier properties to various gases tend to be improved.

[0010] The xylylenediamine is preferably paraxylylenediamine and / or metaxylylenediamine. The xylylenediamine preferably contains 0 to 100 mol % of metaxylylenediamine and 100 to 0 mol % of paraxylylenediamine (provided that the total of metaxylylenediamine and paraxylylenediamine does not exceed 100 mol %), more preferably 10 to 100 mol % of metaxylylenediamine and 90 to 0 mol % of paraxylylenediamine, and even more preferably 30 to 100 mol % of metaxylylenediamine and 70 to 0 mol % of paraxylylenediamine. It is more preferable that the polyamide resin contains 0 to 100 mol% meta-xylylenediamine and 60 to 0 mol% para-xylylenediamine, even more preferable that the polyamide resin contains 60 to 100 mol% meta-xylylenediamine and 40 to 0 mol% para-xylylenediamine, even more preferable that the polyamide resin contains 80 to 100 mol% meta-xylylenediamine and 20 to 0 mol% para-xylylenediamine, and even more preferable that the polyamide resin contains 95 to 100 mol% meta-xylylenediamine and 5 to 0 mol% para-xylylenediamine. The diamines constituting the polyamide resin of this embodiment preferably contain para-xylylenediamine and meta-xylylenediamine in total, accounting for at least 80 mol%, more preferably at least 85 mol%, even more preferably at least 90 mol%, even more preferably at least 95 mol%, even more preferably at least 98 mol%, and even more preferably at least 99 mol% of the diamine. The upper limit of the total amount of para-xylylenediamine and meta-xylylenediamine is 100 mol%.

[0011] Further, examples of diamines other than xylylenediamine that constitute the polyamide resin of this embodiment include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine; 1,3-bis(aminomethyl)cyclohexane; Examples include alicyclic diamines such as 4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminomethyl)decalin, and bis(aminomethyl)tricyclodecane; and diamines having an aromatic ring such as bis(4-aminophenyl)ether, paraphenylenediamine, and bis(aminomethyl)naphthalene, and these can be used alone or in combination of two or more.

[0012] In the polyamide resin of this embodiment, the type of dicarboxylic acid is not particularly limited, but it is preferable that 50 mol % or more of the dicarboxylic acid be an α,ω-straight-chain aliphatic dicarboxylic acid and / or an aromatic dicarboxylic acid having 4 to 20 carbon atoms, more preferably 5 to 100 mol % be an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms and 95 to 0 mol % be isophthalic acid, and even more preferably 85 to 100 mol % be an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms and 15 to 0 mol % be isophthalic acid (however, the total of the α,ω-straight-chain aliphatic dicarboxylic acid and aromatic dicarboxylic acid having 4 to 20 carbon atoms does not exceed 100 mol %).

[0013] More specifically, when the dicarboxylic acid is an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms, it is preferably an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 14 carbon atoms, more preferably one or more of adipic acid, sebacic acid, and dodecanedioic acid, even more preferably adipic acid and / or sebacic acid, and even more preferably adipic acid.

[0014] In a first embodiment of the dicarboxylic acid in the polyamide resin of this embodiment, preferably 50 mol % or more, more preferably 80 mol % or more, even more preferably 90 mol % or more, still more preferably 95 mol % or more, still more preferably 98 mol % or more, and still more preferably 99 mol % or more of the dicarboxylic acid is a C 4 to 20 α,ω-straight-chain aliphatic dicarboxylic acid. In particular, in the first embodiment of the dicarboxylic acid, it is preferable that the C 4 to 20 α,ω-straight-chain aliphatic dicarboxylic acid is adipic acid.

[0015] When the dicarboxylic acid is the first embodiment, the melting point of the polyamide resin is preferably 210°C or higher, more preferably 220°C or higher, and is preferably 236°C or lower, more preferably 235°C or lower.

[0016] The glass transition temperature of the polyamide resin when the dicarboxylic acid is the first embodiment is preferably 86° C. or higher, more preferably 87° C. or higher, and is preferably 100° C. or lower, more preferably 95° C. or lower, and even more preferably 90° C. or lower. The melting point and glass transition temperature of the polyamide resin when the dicarboxylic acid is the first embodiment are measured according to the description in the Examples below (the same applies to the polyamide resin when the dicarboxylic acid is the second embodiment and the polyamide resin when the dicarboxylic acid is the third embodiment).

[0017] The polyamide resin in the case where the dicarboxylic acid is the first embodiment has a melting temperature of 250°C and a shear rate of 121.6 s －１ The melt viscosity measured according to is preferably 510 Pa s or more, more preferably 550 Pa s or more, even more preferably 600 Pa s or more, even more preferably 700 Pa s or more, even more preferably 750 Pa s or more, even more preferably 800 Pa s or more, and is preferably 1500 Pa s or less, more preferably 1200 Pa s or less, and even more preferably 1000 Pa s or less.

[0018] The polyamide resin in the case where the dicarboxylic acid is the first embodiment has a melting temperature of 250°C and a shear rate of 1216 s －１ The melt viscosity measured according to is preferably 240 Pa s or more, more preferably 250 Pa s or more, and even more preferably 260 Pa s or more, and is preferably 500 Pa s or less, more preferably 450 Pa s or less, even more preferably 400 Pa s or less, and even more preferably 350 Pa s or less. The shear rate of the polyamide resin when the dicarboxylic acid is the first embodiment is measured according to the description in the examples described below (the same applies to the polyamide resin when the dicarboxylic acid is the second embodiment and the polyamide resin when the dicarboxylic acid is the third embodiment).

[0019] In a second embodiment of the dicarboxylic acid in the polyamide resin of this embodiment, it is preferable that 95 to 40 mol% is an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms and 5 to 60 mol% is isophthalic acid, more preferably 60 to 40 mol% is an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms and 40 to 60 mol% isophthalic acid, and even more preferably 60 to 43 mol% is an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms and 40 to 57 mol% isophthalic acid.

[0020] When the dicarboxylic acid is used in the second embodiment, the polyamide resin is preferably an amorphous resin that does not have a definite melting point.

[0021] When the dicarboxylic acid is the second embodiment, the glass transition temperature of the polyamide resin is preferably higher than 125°C, more preferably 126°C or higher, and is preferably 135°C or lower, more preferably 132°C or lower, and even more preferably 130°C or lower.

[0022] The polyamide resin in the case where the dicarboxylic acid is the second embodiment has a melting temperature of 250°C and a shear rate of 121.6 s －１The melt viscosity measured according to the method is preferably more than 125 Pa s, more preferably 126 Pa s or more, and is preferably 300 Pa s or less, more preferably 250 Pa s or less, even more preferably 200 Pa s or less, and even more preferably 150 Pa s or less.

[0023] The polyamide resin in the case where the dicarboxylic acid is the second embodiment has a melting temperature of 250°C and a shear rate of 1216 s －１ The melt viscosity measured according to is preferably 1720 Pa s or more, more preferably 1730 Pa s or more, and even more preferably 1735 Pa s or more, and is preferably 2000 Pa s or less, more preferably 1900 Pa s or less, and even more preferably 1800 Pa s or less.

[0024] In a third embodiment of the dicarboxylic acid in the polyamide resin of this embodiment, 97 to 80 mol% is preferably an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms and 3 to 20 mol% is isophthalic acid, more preferably 97 to 85 mol% is an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms and 3 to 15 mol% isophthalic acid, even more preferably 97 to 90 mol% is an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms and 3 to 10 mol% isophthalic acid, and even more preferably 96 to 92 mol% is an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms and 4 to 8 mol% isophthalic acid.

[0025] When the dicarboxylic acid is the third embodiment, the melting point of the polyamide resin is preferably 220°C or higher, more preferably 225°C or higher, and is preferably 229°C or lower, more preferably 228°C or lower.

[0026] When the dicarboxylic acid is the third embodiment, the glass transition temperature of the polyamide resin is preferably more than 92°C, more preferably 93°C or higher, and is preferably 100°C or lower, more preferably 95°C or lower.

[0027] The polyamide resin in the case where the dicarboxylic acid is the third embodiment has a melting temperature of 250°C and a shear rate of 121.6 s －１ The melt viscosity measured according to is preferably 650 Pa s or more, more preferably 700 Pa s or more, and even more preferably 730 Pa s or more, and is preferably 2000 Pa s or less, more preferably 1900 Pa s or less, and even more preferably 1800 Pa s or less.

[0028] The polyamide resin in the case where the dicarboxylic acid is the third embodiment has a melting temperature of 250°C and a shear rate of 1216 s －１ The melt viscosity measured according to the method is preferably 250 Pa·s or more, more preferably 260 Pa·s or more, and is preferably 700 Pa·s or less, more preferably 650 Pa·s or less, and even more preferably 600 Pa·s or less.

[0029] Examples of dicarboxylic acids other than those mentioned above include phthalic acid compounds such as terephthalic acid and orthophthalic acid, and isomers of naphthalenedicarboxylic acids such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid. These dicarboxylic acids may be used singly or in combination. The polyamide resin of this embodiment is preferably substantially free of terephthalic acid. By "substantially free," we mean that the proportion of terephthalic acid is less than 3% by mass, preferably less than 1% by mass, of the dicarboxylic acids constituting the polyamide resin.

[0030] The polyamide resin of this embodiment is copolymerized with trimesic acid together with a diamine and a dicarboxylic acid, with the trimesic acid content being 0.01 to 5 mol % relative to a total of 100 mol % of the diamine, dicarboxylic acid, and trimesic acid. Using such a small amount of trimesic acid results in a polyamide resin with a high melt viscosity. The trimesic acid content is preferably 0.03 mol % or more, more preferably 0.05 mol % or more, even more preferably 0.1 mol % or more, and even more preferably 0.2 mol % or more, and is preferably 4 mol % or less, more preferably 3.5 mol % or less, even more preferably 3 mol % or less, even more preferably 2 mol % or less, and even more preferably 1.5 mol % or less. By setting the content at or above the lower limit, melt tension tends to be further improved. By setting the content at or below the upper limit, processability during molding tends to be further improved.

[0031] The polyamide resin of this embodiment is primarily composed of diamine-derived structural units and dicarboxylic acid-derived structural units, but does not completely exclude other structural units. It goes without saying that the polyamide resin may contain structural units derived from lactams such as ε-caprolactam and laurolactam, and aliphatic aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid. Here, "major component" refers to the structural units constituting the polyamide resin of this embodiment in which the total number of diamine-derived structural units and dicarboxylic acid-derived structural units is the largest among all structural units. In the polyamide resin of this embodiment, the total of the diamine-derived structural units, dicarboxylic acid-derived structural units, and trimesic acid-derived structural units preferably accounts for 90% by mass or more of all structural units, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more.

[0032] The polyamide resin of this embodiment is also preferably a polyamide resin (biomass polyamide resin) produced using biomass raw materials. By using biomass polyamide resin, it is possible to reduce the environmental impact. In the polyamide resin of this embodiment, bioadipic acid can be used as the biomass raw material. Mass balance certified (ISCC PLUS) adipic acid can also be used. Mass balance certification means that the amount of renewable raw materials or bio-based raw materials used in each factory or production facility and the amount of products produced or shipped are quantified and guaranteed together with the quality.

[0033] The polyamide resin of the present embodiment has a number average molecular weight (Mn) of preferably 6,000 or more, more preferably 8,000 or more, and even more preferably 10,000 or more, and is preferably 100,000 or less, and more preferably 50,000 or less. Within such ranges, the heat resistance, elastic modulus, dimensional stability, and moldability are improved.

[0034] The polyamide resin of this embodiment preferably has a weight-average molecular weight (Mw) lower limit of 10,000 or more, more preferably 30,000 or more, even more preferably 50,000 or more, and preferably 140,000 or less, more preferably 120,000 or less. Within these ranges, the heat resistance, elastic modulus, dimensional stability, and moldability are improved. The number-average molecular weight and weight-average molecular weight of the polyamide resin are measured according to the description in the examples below. The polyamide resin of this embodiment may be a crystalline resin with a clear melting point or an amorphous resin without a clear melting point, but is preferably a crystalline resin. Being a crystalline resin allows for high chemical resistance.

[0035] The method for producing a polyamide resin of this embodiment includes copolymerizing a diamine, a dicarboxylic acid, and trimesic acid, and preferably, 50 mol % or more of the diamine is xylylenediamine, and the trimesic acid is 0.01 to 5 mol % relative to a total of 100 mol % of the diamine, dicarboxylic acid, and trimesic acid. The polyamide resin produced by the method of this embodiment is preferably the polyamide resin of this embodiment described above.

[0036] The polyamide resin of this embodiment can be produced by known methods, except for the above points. Preferably, it is produced by melt polycondensation (melt polymerization) using a phosphorus-containing compound as a catalyst, or by the pressurized salt method, and more preferably by the melt polycondensation method. A preferred melt polycondensation method involves adding a raw diamine dropwise to a molten dicarboxylic acid, raising the temperature under pressure, and polymerizing while removing the condensed water. A preferred pressurized salt method involves raising the temperature under pressure in the presence of water to a salt composed of the raw diamine and the raw dicarboxylic acid, and polymerizing in a molten state while removing the added water and condensed water. In this embodiment, the copolymer (polyamide resin) of the diamine, dicarboxylic acid, and trimesic acid may be further solid-phase polymerized. Solid-phase polymerization produces a polyamide resin with a higher molecular weight.

[0037] <Resin Composition> The polyamide resin of this embodiment can be used as a resin composition containing the polyamide resin of this embodiment (hereinafter sometimes referred to as the "resin composition of this embodiment"), or as a molded article formed from the resin composition of this embodiment. The resin composition of this embodiment may consist of only one or more polyamide resins of this embodiment, or may contain other components. Other components include polyamide resins other than the polyamide resin of this embodiment, thermoplastic resins other than polyamide resins, reinforcing materials (fillers), antioxidants (particularly heat stabilizers) such as heat stabilizers and weather stabilizers, flame retardants, flame retardant assistants, release agents, anti-dripping agents, matting agents, UV absorbers, plasticizers, antistatic agents, coloring inhibitors, antigelling agents, nucleating agents, and other additives. Each of these additives may be one type or two or more types. For details, see paragraphs 0047 to 0103 of WO 2021 / 241471, the contents of which are incorporated herein by reference.

[0038] <Method for producing resin composition> The method for producing the resin composition of this embodiment is not particularly limited, and a wide variety of known methods for producing thermoplastic resin compositions can be used. Specifically, the resin composition can be produced by pre-mixing the components using various mixers such as a tumbler or a Henschel mixer, and then melt-kneading them using a Banbury mixer, a roll, a Brabender mixer, a single-screw extruder, a twin-screw extruder, a kneader, or the like.

[0039] The resin composition of the present embodiment can also be produced, for example, without mixing the components in advance, or by mixing only some of the components in advance and supplying the mixture to an extruder using a feeder and melt-kneading it.Furthermore, the resin composition of the present embodiment can also be produced, for example, by mixing some of the components in advance, supplying them to an extruder and melt-kneading them to obtain a resin composition, which is used as a masterbatch, and then mixing this masterbatch again with the remaining components and melt-kneading them.

[0040] <Molded Article> The molded article of this embodiment is molded from the polyamide resin of this embodiment or the resin composition of this embodiment. The method for molding the molded article is not particularly limited, and conventionally known molding methods can be used, such as injection molding, injection compression molding, extrusion molding, profile extrusion, transfer molding, hollow molding, gas-assisted hollow molding, blow molding, extrusion blow molding, IMC (in-mold coating molding), rotational molding, multilayer molding, two-color molding, insert molding, sandwich molding, foam molding, pressure molding, stretching, vacuum molding, etc., with extrusion molding and foam molding being preferred, and extrusion molding being more preferred. That is, the molded article of this embodiment has high melt viscosity and therefore high melt tension, making it suitable as an extrusion molded article. Examples of molded articles formed from the polyamide resin of this embodiment or the resin composition of this embodiment include hollow molded articles (hoses, tubes, etc.), films (including plate-shaped and sheet-shaped), fibers, foams, etc., with films, fibers, or foams being preferred. Foams are produced by blending a blowing agent with a polyamide resin or a resin composition, extruding the mixture, and then foaming the foaming agent. If the polyamide resin has high melt tension at this time, the polyamide resin will stretch appropriately in response to the foaming of the blowing agent, allowing for the production of good foams.

[0041] In addition to the above, molded articles include pipes, gears, cams, various housings, rollers, impellers, bearing retainers, spring holders, clutch parts, chain tensioners, tanks, wheels, connectors, switches, sensors, sockets, capacitors, hard disk parts, jacks, fuse holders, relays, coil bobbins, resistors, IC housings, LED reflectors, intake pipes, blow-by tubes, 3D printer substrates, automotive interior and exterior parts, engine room parts, cooling system parts, sliding parts, automotive supplies such as electrical parts and electronic parts, surface-mounted connectors, sockets, camera modules, power supply parts, switches, sensors, capacitor base plates, hard disk parts, relays, resistors, fuse holders, coil bobbins, IC housings, and other surface-mounted parts, fuel caps, fuel tanks, fuel sender modules, fuel cut-off valves, canisters, and fuel pipes.

[0042] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

[0043] Comparative Example 1 <Synthesis of Polyamide Resin> 9,000 g (61.58 mol) of adipic acid and 13.3 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 0.9 / 1.0) were charged into a jacketed reactor equipped with a stirrer, partial condenser, condenser, thermometer, dropping tank, and nitrogen gas inlet tube, and the contents were thoroughly purged with nitrogen. After heating and melting at 180 ° C, 8,388 g of metaxylylenediamine (61.58 mol of metaxylylenediamine, manufactured by Mitsubishi Gas Chemical Company, Inc.) was added dropwise to the melt in the reactor while stirring, and the resulting condensed water was discharged outside the system, while the temperature was raised to 240 ° C. After the dropwise addition was completed, the temperature was raised to 260 ° C. and continued for 20 minutes. Thereafter, the pressure inside the reaction system was continuously reduced to 0.08 MPa, and the reaction was continued. After the reaction was completed, the reactor was pressurized with nitrogen gas at 0.2 MPa, and the polymer was removed as a strand from a nozzle at the bottom of the polymerization vessel. After water cooling, the polymer was pelletized using a pelletizer to obtain polyamide MXD6. The melting point, glass transition temperature, melt viscosity, melt tension, and molecular weight (Mn, Mw) were measured. The melt viscosity and melt tension were measured after drying the resulting pellets in a vacuum dryer at 130°C for 8 hours.

[0044] <Melting Point (Tm) and Glass Transition Temperature (Tg)> The melting point and glass transition temperature of the polyamide resin were measured by differential scanning calorimetry (DSC). DSC measurements were performed in accordance with JIS K7121 and K7122. Using a differential scanning calorimeter, the synthesized polyamide resin was crushed and placed in the measurement pan of the differential scanning calorimeter. The temperature was raised to the melting point (estimated value) +20°C at a heating rate of 10°C / min under a nitrogen atmosphere. Immediately after the temperature rise was completed, the measurement pan was removed and pressed against dry ice for rapid cooling. Measurements were then performed. The measurement conditions were a heating rate of 10°C / min to approximately melting point +20°C, held for 5 minutes, and then a cooling rate of -5°C / min to 100°C, and the melting point (Tm) and glass transition temperature (Tg) were determined. A "DSC-60" manufactured by Shimadzu Corporation was used as the differential scanning calorimeter. The melting point and glass transition temperature are shown in ° C.

[0045] <Melt viscosity> The melt viscosity of the polyamide resin was measured using a capillograph with a die having a diameter of 1 mm and a length of 10 mm at an apparent shear rate of 121.6 s －１ , 1216s －１ The measurement was performed under the conditions of a measurement temperature of 250° C., a holding time of 6 minutes, and a moisture content of the polyamide resin of 1000 ppm by weight or less. In this example, a Capillograph 1D manufactured by Toyo Seiki Seisakusho, Ltd. was used as the Capillograph.

[0046] <Melt tension> The melt viscosity of the polyamide resin was measured using a Capillograph die having a diameter of 2 mm and a length of 8 mm under the conditions of a measurement temperature of 250°C, a preheating time of 6 minutes, a piston speed of 5 mm / min, and a take-up speed of 5 m / min. In this example, a Capillograph 1D manufactured by Toyo Seiki Seisakusho, Ltd. was used as the Capillograph.

[0047] <Weight average molecular weight and number average molecular weight> The weight average molecular weight (Mw) and number average molecular weight (Mn) of polyamide resin were measured by gel permeation chromatography (GPC) and calculated from the standard polymethyl methacrylate (PMMA) equivalent value. As the column, two columns packed with styrene polymer were used as the filler, and hexafluoroisopropanol (HFIP) with a sodium trifluoroacetate concentration of 2 mmol / L was used as the solvent, and the resin concentration was 0.02 mass%, the column temperature was 40 ° C, the flow rate was 0.3 mL / min, and the refractive index detector (RI) was used for measurement. In addition, the calibration curve was measured by dissolving six levels of PMMA in HFIP.

[0048] Example 1 <Synthesis of Polyamide Resin> 9,000 g (61.58 mol) of adipic acid, 65.0 g (0.31 mol) of trimesic acid, and 13.4 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 0.9 / 1.0) were charged into a jacketed reactor equipped with a stirrer, partial condenser, condenser, thermometer, dropping tank, and nitrogen gas inlet tube. The contents were thoroughly purged with nitrogen and heated to 180 ° C. to melt. Then, while stirring the contents, 8,430 g of metaxylylenediamine (61.89 mol of metaxylylenediamine, manufactured by Mitsubishi Gas Chemical Company, Inc.) was added dropwise to the melt in the reactor. The resulting condensed water was discharged from the system, and the temperature was raised to 240 ° C. After the dropwise addition, the temperature was raised to 260 ° C. and continued for 20 minutes. The pressure inside the reaction system was then continuously reduced to 0.08 MPa, and the reaction was continued. After the reaction was completed, the reactor was pressurized with nitrogen gas at 0.2 MPa, and the polymer was removed as strands from a nozzle at the bottom of the polymerization vessel. After water cooling, the polymer was pelletized in a pelletizer to obtain a polyamide resin. No trimesic acid was detected in the unreacted monomers, confirming that trimesic acid had been incorporated into the polyamide resin. The obtained polyamide resin was evaluated in the same manner as in Comparative Example 1.

[0049] Example 2 <Synthesis of Polyamide Resin> 9,000 g (61.58 mol) of adipic acid, 130.7 g (0.62 mol) of trimesic acid, and 13.5 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 0.9 / 1.0) were charged into a jacketed reactor equipped with a stirrer, partial condenser, condenser, thermometer, dropping tank, and nitrogen gas inlet tube. The contents were thoroughly purged with nitrogen and heated to 180 ° C. to melt. Then, while stirring the contents, 8,473 g of metaxylylenediamine (62.21 mol of metaxylylenediamine, manufactured by Mitsubishi Gas Chemical Company, Inc.) was added dropwise to the melt in the reactor. The resulting condensed water was discharged from the system, and the temperature was raised to 240 ° C. After the dropwise addition, the temperature was raised to 260 ° C. and continued for 20 minutes. The pressure inside the reaction system was then continuously reduced to 0.08 MPa, and the reaction was continued. After the reaction was completed, the reactor was pressurized with nitrogen gas at 0.2 MPa, and the polymer was removed as strands from a nozzle at the bottom of the polymerization vessel. After water cooling, the polymer was pelletized in a pelletizer to obtain a polyamide resin. No trimesic acid was detected in the unreacted monomers, confirming that trimesic acid had been incorporated into the polyamide resin. The obtained polyamide resin was evaluated in the same manner as in Comparative Example 1.

[0050] Comparative Example 2 <Synthesis of Polyamide Resin> 4500 g (30.79 mol) of adipic acid, 5116 g (30.79 mol) of isophthalic acid, and 13.8 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 0.9 / 1.0) were charged into a jacketed reactor equipped with a stirrer, partial condenser, condenser, thermometer, dropping tank, and nitrogen gas inlet tube. The contents were thoroughly purged with nitrogen, heated to 190 ° C. and melted. Then, while stirring the contents, 8388 g of metaxylylenediamine (61.58 mol of metaxylylenediamine, manufactured by Mitsubishi Gas Chemical Company, Inc.) was added dropwise to the melt in the reactor. The resulting condensed water was discharged outside the system, and the temperature was raised to 250 ° C. After the dropwise addition, the temperature was raised to 270 ° C. and continued for 20 minutes. The pressure inside the reaction system was then continuously reduced to 0.08 MPa, and the reaction was continued. After the reaction was completed, the reactor was pressurized with nitrogen gas at 0.2 MPa, and the polymer was removed as a strand from a nozzle at the bottom of the polymerization vessel. After cooling with water, the polymer was pelletized in a pelletizer to obtain a polyamide resin. The obtained polyamide resin was evaluated in the same manner as in Comparative Example 1. However, since it was an amorphous polyamide resin, a clear melting point could not be measured.

[0051] Example 3 <Synthesis of Polyamide Resin> A jacketed reactor equipped with a stirrer, partial condenser, condenser, thermometer, dropping tank, and nitrogen gas inlet tube was charged with 4,500 g (30.79 mol) of adipic acid, 5,064 g (30.48 mol) of isophthalic acid, 64.7 g (0.31 mol) of trimesic acid, and 13.8 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 0.9 / 1.0), thoroughly purged with nitrogen, heated to 190°C and melted. Then, while stirring the contents, 8,388 g of metaxylylenediamine (61.58 mol of metaxylylenediamine, manufactured by Mitsubishi Gas Chemical Company, Inc.) was added dropwise to the melt in the reactor, and the temperature was raised to 250°C while discharging the resulting condensed water out of the system. After the dropwise addition was completed, the temperature was raised to 270°C and continued for 20 minutes. The internal pressure of the reaction system was then continuously reduced to 0.08 MPa, and the reaction was continued. After completion of the reaction, the reactor was pressurized to 0.2 MPa with nitrogen gas, and the polymer was removed as a strand from a nozzle at the bottom of the polymerization vessel. After water cooling, the polymer was pelletized in a pelletizer to obtain a polyamide resin. No trimesic acid was detected in the unreacted monomer, confirming that trimesic acid had been incorporated into the polyamide resin. The obtained polyamide resin was evaluated in the same manner as in Comparative Example 1. However, because it was an amorphous polyamide resin, a clear melting point could not be measured.

[0052] Example 4 <Synthesis of Polyamide Resin> A jacketed reactor equipped with a stirrer, partial condenser, condenser, thermometer, dropping tank, and nitrogen gas inlet tube was charged with 4,500 g (30.79 mol) of adipic acid, 5,013 g (30.18 mol) of isophthalic acid, 129.4 g (0.62 mol) of trimesic acid, and 13.7 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 0.9 / 1.0), thoroughly purged with nitrogen, heated to 190 ° C. to melt, and then, while stirring the contents, 8,388 g of metaxylylenediamine (61.58 mol of metaxylylenediamine, manufactured by Mitsubishi Gas Chemical Company, Inc.) was added dropwise to the melt in the reactor, and the temperature was raised to 250 ° C. while discharging the resulting condensed water out of the system. After the dropwise addition was completed, the temperature was raised to 270 ° C. and continued for 20 minutes. The internal pressure of the reaction system was then continuously reduced to 0.08 MPa, and the reaction was continued. After completion of the reaction, the reactor was pressurized to 0.2 MPa with nitrogen gas, and the polymer was removed as a strand from a nozzle at the bottom of the polymerization vessel. After water cooling, the polymer was pelletized in a pelletizer to obtain a polyamide resin. No trimesic acid was detected in the unreacted monomer, confirming that trimesic acid had been incorporated into the polyamide resin. The obtained polyamide resin was evaluated in the same manner as in Comparative Example 1. However, because it was an amorphous polyamide resin, a clear melting point could not be measured.

[0053] Comparative Example 3 <Synthesis of Polyamide Resin> 9000 g (61.58 mol) of adipic acid, 653 g (3.93 mol) of isophthalic acid, and 14.2 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 0.9 / 1.0) were charged into a jacketed reactor equipped with a stirrer, partial condenser, condenser, thermometer, dropping tank, and nitrogen gas inlet tube, and the contents were thoroughly purged with nitrogen. After heating and melting at 190 ° C, 8923 g of metaxylylenediamine (65.52 mol of metaxylylenediamine, manufactured by Mitsubishi Gas Chemical Company, Inc.) was added dropwise to the melt in the reactor while stirring, and the resulting condensed water was discharged outside the system, while the temperature was raised to 250 ° C. After the dropwise addition was completed, the temperature was raised to 270 ° C. and continued for 20 minutes. Thereafter, the pressure inside the reaction system was continuously reduced to 0.08 MPa, and the reaction was continued. After the reaction was completed, the reactor was pressurized with nitrogen gas at 0.2 MPa, and the polymer was removed as a strand from a nozzle at the bottom of the polymerization vessel. After cooling with water, the polymer was pelletized in a pelletizer to obtain a polyamide resin. The obtained polyamide resin was evaluated in the same manner as in Comparative Example 1.

[0054] Example 5 <Synthesis of Polyamide Resin> A jacketed reactor equipped with a stirrer, partial condenser, condenser, thermometer, dropping tank, and nitrogen gas inlet tube was charged with 9,000 g (61.58 mol) of adipic acid, 599 g (3.60 mol) of isophthalic acid, 68.0 g (0.33 mol) of trimesic acid, and 14.2 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 0.9 / 1.0), thoroughly purged with nitrogen, heated to 190 ° C. to melt, and then, while stirring the contents, 8,923 g of metaxylylenediamine (65.52 mol of metaxylylenediamine, manufactured by Mitsubishi Gas Chemical Company, Inc.) was added dropwise to the melt in the reactor, and the temperature was raised to 250 ° C. while discharging the resulting condensed water out of the system. After the dropwise addition was completed, the temperature was raised to 270 ° C. and continued for 20 minutes. The internal pressure of the reaction system was then continuously reduced to 0.08 MPa, and the reaction was continued. After completion of the reaction, the reactor was pressurized to 0.2 MPa with nitrogen gas, and the polymer was removed as strands from a nozzle at the bottom of the polymerization vessel. After water cooling, the polymer was pelletized in a pelletizer to obtain a polyamide resin. No trimesic acid was detected in the unreacted monomer, confirming that trimesic acid had been incorporated into the polyamide resin. The obtained polyamide resin was evaluated in the same manner as in Comparative Example 1.

[0055] Example 6 <Synthesis of Polyamide Resin> A jacketed reactor equipped with a stirrer, partial condenser, condenser, thermometer, dropping tank, and nitrogen gas inlet tube was charged with 9,000 g (61.58 mol) of adipic acid, 544 g (3.28 mol) of isophthalic acid, 138.0 g (0.66 mol) of trimesic acid, and 14.2 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 0.9 / 1.0), thoroughly purged with nitrogen, heated to 190 ° C. to melt, and then, while stirring the contents, 8,923 g of metaxylylenediamine (65.52 mol of metaxylylenediamine, manufactured by Mitsubishi Gas Chemical Company, Inc.) was added dropwise to the melt in the reactor, and the temperature was raised to 250 ° C. while discharging the resulting condensed water out of the system. After the dropwise addition was completed, the temperature was raised to 270 ° C. and continued for 20 minutes. The internal pressure of the reaction system was then continuously reduced to 0.08 MPa, and the reaction was continued. After completion of the reaction, the reactor was pressurized to 0.2 MPa with nitrogen gas, and the polymer was removed as strands from a nozzle at the bottom of the polymerization vessel. After water cooling, the polymer was pelletized in a pelletizer to obtain a polyamide resin. No trimesic acid was detected in the unreacted monomer, confirming that trimesic acid had been incorporated into the polyamide resin. The obtained polyamide resin was evaluated in the same manner as in Comparative Example 1.

[0056]

[0057] Reference Example 1 The melting point, glass transition temperature and melt viscosity of polyamide MXD6 (S6001, manufactured by Mitsubishi Gas Chemical Company, Inc.) synthesized from metaxylylenediamine and adipic acid were measured in the same manner as in Comparative Example 1.

[0058] Reference Example 2 Polyamide MXD6 (Mitsubishi Gas Chemical Company, Inc., S6001) synthesized from metaxylylenediamine and adipic acid and trimesic acid were weighed as shown in Table 3 (each component is in parts by mass), blended in a tumbler, and fed into the base of a twin-screw extruder (Shibaura Machine Co., Ltd., TEM26SS) and melt-kneaded to produce pellets of a resin composition. The temperature of the twin-screw extruder was set to 280°C. The melting point, glass transition temperature, and melt viscosity of the resin composition were measured in the same manner as in Comparative Example 1.

[0059] Reference Example 3: Polyamide MXD6 (Mitsubishi Gas Chemical Company, Inc., S6001) synthesized from metaxylylenediamine and adipic acid and trimesic acid were weighed as shown in Table 3 (each component is in parts by mass), blended in a tumbler, and fed into the base of a twin-screw extruder (Shibaura Machine Co., Ltd., TEM26SS) and melt-kneaded to produce pellets of a resin composition. The temperature of the twin-screw extruder was set to 280°C. The melting point, glass transition temperature, and melt viscosity of the resin composition were measured in the same manner as in Comparative Example 1.

[0060]

[0061] As is clear from the above results, the polyamide resin of the present embodiment had a high melt viscosity and a high melt tension (Examples 1 to 6). In contrast, when trimesic acid was not included (Comparative Examples 1 to 3), the melt viscosity and melt tension were low. Furthermore, when trimesic acid was blended with the polyamide resin and melt-kneaded (Reference Examples 2 and 3), the blended polyamide resin had a lower melt viscosity.

Claims

1. A polyamide resin which is a copolymer of a diamine, a dicarboxylic acid, and trimesic acid, in which 50 mol % or more of the diamine is xylylenediamine, and the trimesic acid accounts for 0.01 to 5 mol % relative to 100 mol % in total of the diamine, dicarboxylic acid, and trimesic acid.

2. The polyamide resin according to claim 1, wherein 50 mol % or more of the dicarboxylic acids are α,ω-straight-chain aliphatic dicarboxylic acids and / or aromatic dicarboxylic acids having 4 to 20 carbon atoms.

3. The polyamide resin according to claim 1, wherein 5 to 100 mol % of the dicarboxylic acid is a straight-chain α,ω-aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and 95 to 0 mol % is isophthalic acid.

4. The polyamide resin according to claim 1, wherein 60 to 40 mol % of the dicarboxylic acid is an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and 40 to 60 mol % is isophthalic acid.

5. The polyamide resin according to claim 1, wherein 97 to 80 mol % of the dicarboxylic acid is an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and 3 to 20 mol % is isophthalic acid.

6. The polyamide resin according to any one of claims 1 to 5, wherein 5 to 100 mol % of the dicarboxylic acid is one or more of adipic acid, sebacic acid, and dodecanedioic acid.

7. The polyamide resin is melted at a temperature of 250°C and a shear rate of 121.6 s －１ The polyamide resin according to any one of claims 1 to 6, having a melt viscosity of 510 Pa·s or more as measured according to the method described above.

8. A resin composition comprising the polyamide resin according to any one of claims 1 to 7.

9. A molded article formed from a resin composition containing the polyamide resin according to any one of claims 1 to 7.

10. The molded article according to claim 9, which is an extrusion molded article.

11. The molded article according to claim 9 or 10, which is a film, a fiber or a foam.

12. A method for producing a polyamide resin, comprising copolymerizing a diamine, a dicarboxylic acid, and trimesic acid, wherein 50 mol % or more of the diamine is xylylenediamine, and the trimesic acid is 0.01 to 5 mol % relative to 100 mol % in total of the diamine, dicarboxylic acid, and trimesic acid.

13. A method for producing a polyamide resin, wherein the polyamide resin is the polyamide resin described in any one of claims 1 to 7.

14. A method for producing a molded article, comprising extrusion molding the resin composition according to claim 8.

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