JP7252827B2 - Polyamide composition - Google Patents

Description

The present invention relates to polyamide compositions and the like. More particularly, it relates to a polyamide composition containing a semi-aromatic polyamide having dicarboxylic acid units mainly composed of naphthalenedicarboxylic acid units and diamine units mainly composed of aliphatic diamine units and an organic heat stabilizer.

Semi-aromatic polyamides using aromatic dicarboxylic acids such as terephthalic acid and aliphatic diamines, and crystalline polyamides such as nylon 6 and nylon 66 are used for clothing because of their excellent properties and ease of melt molding. It is widely used as a fiber for industrial materials, general-purpose engineering plastics, etc. On the other hand, problems such as insufficient heat resistance and poor dimensional stability due to water absorption have been pointed out for these crystalline polyamides. In recent years, in particular, resinification of engine room parts has been actively studied for the purpose of improving fuel efficiency of automobiles. There is a desire for polyamides with

As a polyamide having excellent heat resistance, for example, Patent Document 1 discloses a semi-aromatic polyamide obtained from 2,6-naphthalenedicarboxylic acid and a linear aliphatic diamine having 9 to 13 carbon atoms. Patent Document 1 describes that the semi-aromatic polyamide is excellent in chemical resistance, mechanical properties, etc. in addition to heat resistance. On the other hand, Patent Document 1 describes that the use of an aliphatic diamine having a side chain is not preferable because the crystallinity of the obtained polyamide is lowered.

In Patent Document 2, 60 to 100 mol% of dicarboxylic acid units are composed of 2,6-naphthalenedicarboxylic acid units, and 60 to 100 mol% of diamine units are composed of 1,9-nonanediamine units and 2-methyl-1,8 -octanediamine units and having a molar ratio of 1,9-nonanediamine units to 2-methyl-1,8-octanediamine units of from 60:40 to 99:1. Patent Document 2 describes that the polyamide is excellent in mechanical properties, thermal decomposition resistance, low water absorption, chemical resistance, etc., in addition to heat resistance.
Furthermore, resin compositions containing semi-aromatic polyamides and uses of semi-aromatic polyamides have also been disclosed (for example, Patent Documents 3 and 4).

JP-A-50-67393 JP-A-9-12715 WO2012/098840 WO2005/102681

As described above, conventional polyamides such as Patent Documents 1 and 2 have physical properties such as heat resistance, mechanical properties, low water absorption, and chemical resistance, but further improvements in these physical properties are required.
Patent Document 2 describes the combined use of 1,9-nonanediamine and 2-methyl-1,8-octanediamine as aliphatic diamines. No mention is made of polyamides in the high proportion region.

Accordingly, an object of the present invention is to provide a polyamide composition which is excellent in various physical properties such as chemical resistance and high-temperature heat resistance, and a molded article made from the composition.

As a result of intensive studies by the present inventors, a specific polyamide having a dicarboxylic acid unit mainly composed of a naphthalene dicarboxylic acid unit and a diamine unit mainly composed of a branched aliphatic diamine unit and a polyamide containing an organic heat stabilizer The present inventors have found that the composition can solve the above problems, and have completed the present invention through further studies based on this finding.
That is, the present invention is as follows.

[1] containing a polyamide (A) having a dicarboxylic acid unit and a diamine unit and an organic heat stabilizer (B),
More than 40 mol% and 100 mol% or less of the dicarboxylic acid units are naphthalene dicarboxylic acid units,
60 mol % or more and 100 mol % or less of the diamine units are branched aliphatic diamine units and linear aliphatic diamine units as optional structural units, and the branched aliphatic diamine units and the linear aliphatic diamine A polyamide composition in which the proportion of said branched aliphatic diamine unit is 60 mol % or more with respect to 100 mol % in total with the unit.
[2] A molded article made of the polyamide composition.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a polyamide composition excellent in various physical properties such as chemical resistance and high-temperature heat resistance, and a molded article made from the composition.

2-methyl- 1 is a graph plotting the melting point (° C.) of a polyamide against the content ratio (mol %) of 1,8-octanediamine units.

The present invention will be described in detail below. In this specification, any definition that is considered preferable can be adopted arbitrarily, and it can be said that a combination of preferable items is more preferable. In this specification, the description "XX to YY" means "XX or more and YY or less".

<Polyamide composition>
The polyamide composition of the present invention contains a polyamide (A) having dicarboxylic acid units and diamine units, and an organic heat stabilizer (B).
As used herein, the term "unit" (here, "to" indicates a monomer) means "a structural unit derived from". For example, the term "dicarboxylic acid unit" means "derived from a A "structural unit" means a "structural unit derived from a diamine".

[Polyamide (A)]
Polyamide (A) contained in the polyamide composition of the present invention has dicarboxylic acid units and diamine units. More than 40 mol % and 100 mol % or less of the dicarboxylic acid units are naphthalenedicarboxylic acid units. In addition, 60 mol % or more and 100 mol % or less of the diamine units are branched aliphatic diamine units and linear aliphatic diamine units as optional structural units, and the branched aliphatic diamine units and the linear aliphatic The proportion of the branched aliphatic diamine unit is 60 mol % or more with respect to the total 100 mol % with the group diamine unit.
From the viewpoint of chemical resistance, the content of the polyamide (A) contained in the polyamide composition is preferably 50% by mass or more, more preferably 60% by mass or more, and 70% by mass or more. is more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and 99% by mass from the viewpoint of mechanical properties and heat resistance. It is preferably 0.9% by mass or less, more preferably 99.8% by mass or less.

As described above, the polyamide (A) has dicarboxylic acid units mainly composed of naphthalenedicarboxylic acid units and diamine units mainly composed of branched aliphatic diamine units, thereby improving various properties such as chemical resistance. It has excellent physical properties, and the polyamide composition of the present invention containing the polyamide (A) and an organic heat stabilizer maintains the above-mentioned excellent properties and exhibits excellent high-temperature heat resistance. Various molded articles obtained from the polyamide composition can retain the excellent properties of the polyamide composition.

Physical properties such as high-temperature strength, mechanical properties, heat resistance, low water absorption, and chemical resistance that polyamides generally possess tend to improve as the crystallinity of the polyamide increases. Further, among polyamides having similar primary structures, the higher the crystallinity of the polyamide, the higher the melting point of the polyamide. Here, regarding the melting point of the polyamide, for example, a polyamide in which the diamine unit is a 1,9-nonanediamine unit and/or a 2-methyl-1,8-octanediamine unit and the dicarboxylic acid unit is a terephthalic acid unit is taken as an example. and the melting point of the polyamide (vertical axis) and the composition of diamine units (content ratio of 1,9-nonanediamine units and 2-methyl-1,8-octanediamine units) (horizontal axis). is the minimum part. The melting points at both ends on the horizontal axis of the graph, that is, the melting point A1 when the linear 1,9-nonanediamine unit is 100 mol% and the branched 2-methyl-1,8-octanediamine unit is 100 mol. %, the melting point A1 is usually higher than the melting point B1 depending on the molecular structure of the diamine unit.
On the other hand, in the case of a polyamide in which the diamine unit is a 1,9-nonanediamine unit and/or a 2-methyl-1,8-octanediamine unit and the dicarboxylic acid unit is a 2,6-naphthalenedicarboxylic acid unit, the above While the minimum part is shown in a graph having the same vertical axis and horizontal axis as in, the melting point A2 when the 1,9-nonanediamine unit of the linear structure is 100 mol%, and the branched structure 2-methyl-1 When comparing the melting point B2 with 100 mol % of the ,8-octanediamine unit, it was surprisingly found that the melting point B2 is higher than the melting point A2.

Specifically, for a polyamide in which the dicarboxylic acid unit is a 2,6-naphthalene dicarboxylic acid unit and the diamine unit is a 1,9-nonanediamine unit and/or a 2-methyl-1,8-octanediamine unit, FIG. 1 shows a graph in which the melting point (° C.) of the polyamide is plotted against the 2-methyl-1,8-octanediamine unit content (mol %).
According to FIG. 1, 2-methyl-1,8 - It can be seen that the melting point of the polyamide decreases as the octanediamine unit content increases. On the other hand, when the content of 2-methyl-1,8-octanediamine units exceeds 50 mol %, it can be seen that the melting point of the polyamide increases significantly as the content increases. Comparing the melting points near both ends on the horizontal axis in FIG. It can be seen that the melting point is higher than the melting point when the content of 1,9-nonanediamine units in the structure is 100 mol %. Also for portions other than the vicinity of both ends on the horizontal axis, when the melting point of the region on the left and right of the border around the content of 50 mol% of the 2-methyl-1,8-octanediamine unit is compared, 2-methyl It can be seen that the melting point tends to be higher in the region on the right where the content of -1,8-octanediamine units is higher than in the region on the left where the content of 1,9-nonanediamine units is higher.

As described above, it was found that polyamides having diamine units mainly composed of 1,9-nonanediamine units and/or 2-methyl-1,8-octanediamine units exhibit different physical properties depending on the combined dicarboxylic acid units. . As a result of further studies by the present inventors, when the content of branched aliphatic diamine units is higher than that of linear aliphatic diamine units, by adopting naphthalene dicarboxylic acid units as dicarboxylic acid units, resistance It was found that various physical properties such as chemical resistance and high-temperature heat resistance were further improved. Although the reason for this is not necessarily clear, it is presumed to be due to the mutual relationship between the appropriate ratio of the branched structure in the diamine unit and the presence of the naphthalene skeleton in the dicarboxylic unit in the polyamide.

(Dicarboxylic acid unit)
More than 40 mol % and 100 mol % or less of dicarboxylic acid units are naphthalenedicarboxylic acid units. If the content of the naphthalenedicarboxylic acid unit in the dicarboxylic acid unit is 40 mol % or less, it becomes difficult to exhibit the effect of improving various physical properties such as chemical resistance and high-temperature heat resistance of the polyamide composition.
From the viewpoint of mechanical properties, heat resistance, chemical resistance, etc., the content of the naphthalenedicarboxylic acid unit in the dicarboxylic acid unit is preferably 50 mol% or more, more preferably 60 mol% or more, and 70% by mol or more. It is more preferably 80 mol % or more, even more preferably 90 mol % or more, and particularly preferably 100 mol %.

Examples of naphthalenedicarboxylic acid units include 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, structural units derived from naphthalenedicarboxylic acid such as 2,7-naphthalenedicarboxylic acid. be done. Only one type of these structural units may be contained, or two or more types may be contained. Among the above naphthalenedicarboxylic acids, 2,6-naphthalenedicarboxylic acid is preferable from the viewpoint of the development of various physical properties including chemical resistance and high-temperature heat resistance of the polyamide composition and reactivity with diamines.
From the same viewpoint as above, the content of structural units derived from 2,6-naphthalenedicarboxylic acid in naphthalenedicarboxylic acid units is preferably 90 mol% or more, more preferably 95 mol% or more. , 100 mol % (substantially 100 mol %) is preferable.

The dicarboxylic acid unit may contain structural units derived from dicarboxylic acids other than naphthalenedicarboxylic acid, as long as the effects of the present invention are not impaired.
Examples of other dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, dimethylmalonic acid, 2 , 2-diethylsuccinic acid, 2,2-dimethylglutaric acid, 2-methyladipic acid, trimethyladipic acid and other aliphatic dicarboxylic acids; 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1, alicyclic dicarboxylic acids such as 4-cyclohexanedicarboxylic acid, cycloheptanedicarboxylic acid, cyclooctanedicarboxylic acid, cyclodecanedicarboxylic acid; terephthalic acid, isophthalic acid, diphenic acid, 4,4′-biphenyldicarboxylic acid, diphenylmethane-4, aromatic dicarboxylic acids such as 4'-dicarboxylic acid and diphenylsulfone-4,4'-dicarboxylic acid; 1 type of structural units derived from these other dicarboxylic acids may be contained, and 2 or more types may be contained.
The content of structural units derived from other dicarboxylic acids in dicarboxylic acid units is preferably 50 mol% or less, more preferably 40 mol% or less, and even more preferably 30 mol% or less. , is more preferably 20 mol % or less, and even more preferably 10 mol % or less.

(diamine unit)
60 mol % or more and 100 mol % or less of the diamine units are branched aliphatic diamine units and straight-chain aliphatic diamine units as arbitrary constitutional units. That is, the diamine units either contain branched aliphatic diamine units and no linear aliphatic diamine units, or contain both branched and linear aliphatic diamine units, and the diamine The total content of branched aliphatic diamine units and linear aliphatic diamine units, which are optional structural units, is 60 mol % or more and 100 mol % or less. When the total content of the branched aliphatic diamine unit and the linear aliphatic diamine unit in the diamine unit is less than 60 mol%, various physical properties such as chemical resistance and high temperature heat resistance in the polyamide composition are improved. It becomes difficult to express.
From the viewpoint of chemical resistance, mechanical properties, heat resistance, etc., the total content of the branched aliphatic diamine unit and the linear aliphatic diamine unit in the diamine unit is preferably 70 mol% or more, and 80 mol. % or more, more preferably 90 mol % or more, and particularly preferably 100 mol %.
In the present specification, the term "branched aliphatic diamine" refers to a linear aliphatic chain having carbon atoms at both ends which are carbon atoms to which two amino groups are respectively bonded. means an aliphatic diamine having a structure in which one or more of the hydrogen atoms in the aliphatic chain (the assumed aliphatic chain) of is replaced by a branched chain. Thus, for example, 1,2-propanediamine (H ₂ N--CH(CH ₃ )--CH ₂ --NH ₂ ) has one of the hydrogen atoms of the 1,2-ethylene group as the assumed aliphatic chain It is classified as a branched aliphatic diamine in the present specification because it has a structure substituted with a methyl group of .

In the diamine units, the ratio of branched aliphatic diamine units to 100 mol % of the total of branched aliphatic diamine units and linear aliphatic diamine units is 60 mol % or more. When the proportion of the branched aliphatic diamine units is less than 60 mol %, it becomes difficult to achieve the effect of improving various physical properties such as chemical resistance and high-temperature heat resistance of the polyamide composition.
From the viewpoint of easily improving various physical properties such as chemical resistance and high-temperature heat resistance and improving the moldability of the polyamide composition, a total of 100 branched aliphatic diamine units and linear aliphatic diamine units The ratio of branched aliphatic diamine units to mol % is preferably 65 mol % or more, more preferably 70 mol % or more, further preferably 72 mol % or more, and 77 mol % or more. More preferably, it is 80 mol % or more, and may be 90 mol % or more. Although the ratio may be 100 mol%, it is preferably 99 mol% or less, preferably 98 mol% or less, and even 95 mol% or less in consideration of moldability and diamine availability. good.

The number of carbon atoms in the branched aliphatic diamine unit is preferably 4 or more, more preferably 6 or more, still more preferably 8 or more, and preferably 18 or less, and 12 or less. is more preferable. If the number of carbon atoms in the branched aliphatic diamine unit is within the above range, the polymerization reaction between the dicarboxylic acid and the diamine will proceed well, the crystallinity of the polyamide (A) will be good, and the polyamide composition containing the polyamide (A) will be obtained. The physical properties of things are easier to improve. Examples of preferred embodiments of the number of carbon atoms in the branched aliphatic diamine unit include 4 or more and 18 or less, 4 or more and 12 or less, 6 or more and 18 or less, 6 or more and 12 or less, or 8 or more and 18 or less. , 8 or more and 12 or less.

The type of branched chain in the branched aliphatic diamine unit is not particularly limited, and may be, for example, various aliphatic groups such as a methyl group, an ethyl group, and a propyl group. A structural unit derived from a diamine having at least one selected from the group consisting of a methyl group and an ethyl group as a chain is preferred. When a diamine having at least one selected from the group consisting of a methyl group and an ethyl group as a branched chain is used, the polymerization reaction between the dicarboxylic acid and the diamine proceeds well, and the chemical resistance of the polyamide composition containing the polyamide (A) is improved. performance can be improved more easily. From this point of view, the branched chain is more preferably a methyl group.
The number of branched chains of the branched aliphatic diamine that forms the branched aliphatic diamine unit is not particularly limited, but the number is preferably 3 or less because the effects of the present invention are exhibited more remarkably. , is more preferably two or less, and more preferably one.

Branched aliphatic diamine unit, when the carbon atom to which any one amino group is bonded is the 1st position, the carbon atom at the 2nd position adjacent to it (the carbon atom on the assumed aliphatic chain described above) and the 2nd position is preferably a structural unit derived from a diamine having at least one of the branched chains on at least one of the 3-position carbon atoms (carbon atoms on the assumed aliphatic chain) adjacent to the carbon atom of the above 2 Structural units derived from diamines having at least one of the branched chains at the carbon atoms of the positions are more preferred. As a result, various physical properties such as chemical resistance and high-temperature heat resistance of the polyamide composition are more likely to be improved.

Examples of branched aliphatic diamine units include 1,2-propanediamine, 1-butyl-1,2-ethanediamine, 1,1-dimethyl-1,4-butanediamine, 1-ethyl-1,4- Butanediamine, 1,2-dimethyl-1,4-butanediamine, 1,3-dimethyl-1,4-butanediamine, 1,4-dimethyl-1,4-butanediamine, 2-methyl-1,3- Propanediamine, 2-methyl-1,4-butanediamine, 2,3-dimethyl-1,4-butanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2 ,5-dimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, 3,3-dimethyl-1,6-hexanediamine, 2,2-dimethyl-1,6-hexanediamine , 2,4-diethyl-1,6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2-ethyl-1, 7-heptanediamine, 2-methyl-1,8-octanediamine, 3-methyl-1,8-octanediamine, 1,3-dimethyl-1,8-octanediamine, 1,4-dimethyl-1,8- octanediamine, 2,4-dimethyl-1,8-octanediamine, 3,4-dimethyl-1,8-octanediamine, 4,5-dimethyl-1,8-octanediamine, 2,2-dimethyl-1, 8-octanediamine, 3,3-dimethyl-1,8-octanediamine, 4,4-dimethyl-1,8-octanediamine, 2-methyl-1,9-nonanediamine, 5-methyl-1,9-nonanediamine Structural units derived from branched aliphatic diamines such as Only one type of these structural units may be contained, or two or more types may be contained.
Among the branched aliphatic diamine units, 2-methyl-1,5-pentanediamine, 3-methyl-1, Structural units derived from at least one diamine selected from the group consisting of 5-pentanediamine, 2-methyl-1,8-octanediamine, and 2-methyl-1,9-nonanediamine are preferred, and 2-methyl-1 ,8-octanediamine is more preferred.

The number of carbon atoms in the linear aliphatic diamine unit is preferably 4 or more, more preferably 6 or more, still more preferably 8 or more, and preferably 18 or less, and 12 or less. It is more preferable to have When the number of carbon atoms in the linear aliphatic diamine unit is within the above range, the polymerization reaction between the dicarboxylic acid and the diamine proceeds well, the crystallinity of the polyamide is improved, and the physical properties of the polyamide are easily improved. Examples of preferred embodiments of the number of carbon atoms in the linear aliphatic diamine unit include 4 or more and 18 or less, 4 or more and 12 or less, 6 or more and 18 or less, 6 or more and 12 or less, or 8 or more and 18 or less. It may be 8 or more and 12 or less.
The number of carbon atoms in the linear aliphatic diamine unit and the above-described branched aliphatic diamine unit may be the same or different. is preferred.

Linear aliphatic diamine units include, for example, ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1 ,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1, Structural units derived from linear aliphatic diamines such as 15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, and 1,18-octadecanediamine can be mentioned. Only one type of these structural units may be contained, or two or more types may be contained.
Among the linear aliphatic diamine units, the effect of the present invention is exhibited more remarkably, and from the viewpoint of improving the heat resistance of the polyamide composition containing the obtained polyamide (A) in particular, 1,4-butane is used. diamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine, preferably a structural unit derived from at least one diamine, and more preferably a structural unit derived from 1,9-nonanediamine.

The diamine unit can contain structural units derived from diamines other than branched aliphatic diamines and linear aliphatic diamines, as long as the effects of the present invention are not impaired. Examples of other diamines include alicyclic diamines and aromatic diamines.
Alicyclic diamines include, for example, cyclohexanediamine, methylcyclohexanediamine, isophoronediamine, norbornanedimethylamine, tricyclodecanedimethyldiamine, and the like.
Examples of aromatic diamines include p-phenylenediamine, m-phenylenediamine, p-xylylenediamine, m-xylylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, 4,4 '-diaminodiphenyl ether and the like.
1 type of structural units derived from these other diamines may be contained, and 2 or more types may be contained.
The content of structural units derived from other diamines in the diamine unit is preferably 30 mol % or less, more preferably 20 mol % or less, and even more preferably 10 mol % or less.

(Dicarboxylic acid unit and diamine unit)
The molar ratio of dicarboxylic acid units to diamine units [dicarboxylic acid units/diamine units] in the polyamide (A) is preferably from 45/55 to 55/45. When the molar ratio of the dicarboxylic acid unit to the diamine unit is within the above range, the polymerization reaction proceeds favorably, and a polyamide composition having desired excellent physical properties can be easily obtained.
The molar ratio between the dicarboxylic acid units and the diamine units can be adjusted according to the compounding ratio (molar ratio) between the starting dicarboxylic acid and the starting diamine.

The total ratio of dicarboxylic acid units and diamine units in the polyamide (A) (the ratio of the total number of moles of dicarboxylic acid units and diamine units to the number of moles of all structural units constituting the polyamide (A)) is 70 mol% or more. preferably 80 mol % or more, more preferably 90 mol % or more, 95 mol % or more, or even 100 mol %. When the total ratio of the dicarboxylic acid units and the diamine units is within the above range, the polyamide composition will have more excellent physical properties than desired.

(aminocarboxylic acid unit)
Polyamide (A) may further contain aminocarboxylic acid units in addition to dicarboxylic acid units and diamine units.
Examples of aminocarboxylic acid units include structural units derived from lactams such as caprolactam and lauryllactam; aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid. The content of aminocarboxylic acid units in the polyamide (A) is preferably 40 mol% or less, preferably 20 mol% or less, relative to the total 100 mol% of the dicarboxylic acid units and diamine units constituting the polyamide (A). is more preferable.

(Polyvalent carboxylic acid unit)
Polyamide (A) contains structural units derived from trivalent or higher polyvalent carboxylic acids such as trimellitic acid, trimesic acid, pyromellitic acid, etc. within a range that does not impair the effects of the present invention. can also be included with

(terminal blocker unit)
The polyamide (A) may contain structural units derived from a terminal blocker (terminal blocker units).
The terminal blocker unit is preferably 1.0 mol% or more, more preferably 1.2 mol% or more, and 1.5 mol% or more with respect to 100 mol% of the diamine unit. is more preferably 10 mol % or less, more preferably 7.5 mol % or less, and even more preferably 6.5 mol % or less. When the content of the terminal blocker unit is within the above range, the polyamide composition is excellent in mechanical strength and fluidity. The content of the terminal blocking agent unit can be set within the above desired range by appropriately adjusting the amount of the terminal blocking agent when charging the polymerization raw material. Considering volatilization of the monomer components during polymerization, the charging amount of the terminal blocker should be finely adjusted so that the desired amount of terminal blocker units are introduced into the resulting polyamide (A). is desirable.
As a method for determining the content of terminal blocker units in the polyamide (A), for example, as shown in JP-A-7-228690, the solution viscosity is measured, and the number average molecular weight is calculated. A method of calculating the total amount of terminal groups from the relational expression and subtracting the amounts of amino groups and carboxyl groups obtained by titration from this, or using ¹ H-NMR to obtain signals corresponding to each of the diamine unit and the terminal blocking agent unit. and the like, and the latter is preferable.

A monofunctional compound having reactivity with a terminal amino group or a terminal carboxyl group can be used as the terminal blocking agent. Specific examples include monocarboxylic acids, acid anhydrides, monoisocyanates, monoacid halides, monoesters, monoalcohols, and monoamines. From the viewpoint of reactivity and stability of the terminal to be blocked, monocarboxylic acid is preferable as the terminal blocking agent for the terminal amino group, and monoamine is preferable as the terminal blocking agent for the terminal carboxyl group. From the standpoint of ease of handling, etc., monocarboxylic acids are more preferable as terminal blocking agents.

The monocarboxylic acid used as a terminal blocking agent is not particularly limited as long as it is reactive with amino groups, and examples thereof include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, and laurin. acids, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, aliphatic monocarboxylic acids such as isobutyric acid; alicyclic monocarboxylic acids such as cyclopentanecarboxylic acid and cyclohexanecarboxylic acid; benzoic acid, toluic acid, aromatic monocarboxylic acids such as α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid; and any mixture thereof. Among these, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, and stearic acid are preferred in terms of reactivity, stability of blocked ends, and price. , and benzoic acid are preferred.

The monoamine used as the terminal blocking agent is not particularly limited as long as it has reactivity with carboxyl groups. Examples include methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, and stearyl. Aliphatic monoamines such as amine, dimethylamine, diethylamine, dipropylamine and dibutylamine; Alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; Aromatic monoamines such as aniline, toluidine, diphenylamine and naphthylamine; Mixtures of any of these can be mentioned. Among these, at least one selected from the group consisting of butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline in terms of reactivity, high boiling point, stability of capped ends, and price. is preferred.

The polyamide (A) preferably has an intrinsic viscosity [η _inh ] of 0.1 dl/g or more, measured at a concentration of 0.2 g/dl and a temperature of 30° C., using concentrated sulfuric acid as a solvent, and 0.4 dl/g or more. more preferably 0.6 dl/g or more, particularly preferably 0.8 dl/g or more, and preferably 3.0 dl/g or less, and 2.0 dl/g /g or less, more preferably 1.8 dl/g or less. When the intrinsic viscosity [η _inh ] of the polyamide (A) is within the above range, various physical properties such as moldability are further improved. The intrinsic viscosity [η _inh ] is determined by the flowing time t ₀ (seconds) of the solvent (concentrated sulfuric acid), the flowing time t ₁ (seconds) of the sample solution, and the sample concentration c (g/dl) in the sample solution (i.e., 0.2 g /dl), it can be obtained from the relational expression η _inh =[ln(t ₁ /t ₀ )]/c.

The melting point of the polyamide (A) is not particularly limited, and can be, for example, 260° C. or higher, 270° C. or higher, or even 280° C. or higher. ° C. or higher, more preferably 295 ° C. or higher, more preferably 300 ° C. or higher, even more preferably 305 ° C. or higher, even more preferably 310 ° C. or higher, It may be 315°C or higher. Although the upper limit of the melting point of the polyamide (A) is not particularly limited, it is preferably 330° C. or less, more preferably 320° C. or less, and even more preferably 317° C. or less in consideration of moldability. . The melting point of the polyamide (A) can be obtained as the peak temperature of the melting peak that appears when the temperature is raised at a rate of 10 ° C./min using a differential scanning calorimetry (DSC) device. It can be obtained by the method described.

The glass transition temperature of the polyamide (A) is not particularly limited, and can be, for example, 100° C. or higher, 110° C. or higher, or even 120° C. or higher. , preferably 125° C. or higher, more preferably 130° C. or higher, even more preferably 135° C. or higher, even more preferably 137° C. or higher, and even more preferably 138° C. or higher. Preferably, it may be 139° C. or higher. The upper limit of the glass transition temperature of the polyamide (A) is not particularly limited, but considering moldability etc., it is preferably 180 ° C. or less, more preferably 160 ° C. or less, and 150 ° C. or less. More preferred. The glass transition temperature of the polyamide (A) can be obtained as the temperature of the inflection point that appears when the temperature is raised at a rate of 20 ° C./min using a differential scanning calorimetry (DSC) device. It can be obtained by the method described in the example.

(Method for producing polyamide (A))
The polyamide (A) can be produced by any method known as a method for producing a crystalline polyamide. It can be produced by a method such as an extrusion polymerization method. Among these, the method for producing polyamide (A) is preferably a solid-phase polymerization method from the viewpoint of being able to better suppress thermal deterioration during polymerization.
In order to set the molar ratio of the branched aliphatic diamine unit to the straight-chain aliphatic diamine unit within the specific numerical range described above, the branched aliphatic diamine and the straight-chain aliphatic diamine used as raw materials are desirably may be used at a compounding ratio that provides a molar ratio of the above units.
When 2-methyl-1,8-octanediamine and 1,9-nonanediamine, for example, are used as the branched aliphatic diamine and linear aliphatic diamine, respectively, these can be produced by known methods. Known methods include, for example, a method of distilling a diamine crude reaction liquid obtained by a reductive amination reaction using a dialdehyde as a starting material. Furthermore, 2-methyl-1,8-octanediamine and 1,9-nonanediamine can be obtained by fractionating the diamine crude reaction liquid.

For the polyamide (A), for example, a diamine, a dicarboxylic acid, and, if necessary, a catalyst or a terminal blocking agent are added all at once to produce a nylon salt, and then heated and polymerized at a temperature of 200 to 250 ° C. It can be produced by preparing a prepolymer by heating and then solid-phase polymerizing it, or by polymerizing it using a melt extruder. When the final stage of polymerization is carried out by solid phase polymerization, it is preferably carried out under reduced pressure or under inert gas flow. Coloring and gelation can be effectively suppressed. When the final stage of polymerization is carried out using a melt extruder, the polymerization temperature is preferably 370° C. or less. Polymerization under such conditions yields a polyamide with little degradation and little decomposition.

Examples of catalysts that can be used in producing the polyamide (A) include phosphoric acid, phosphorous acid, hypophosphorous acid, and salts or esters thereof. Examples of the above salts or esters include phosphoric acid, phosphorous acid, or hypophosphorous acid and potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese, tin, tungsten, germanium, titanium, antimony, and the like. Salt with metal; Ammonium salt of phosphoric acid, phosphorous acid or hypophosphite; Ethyl ester, isopropyl ester, butyl ester, hexyl ester, isodecyl ester, octadecyl ester of phosphoric acid, phosphorous acid or hypophosphorous acid , decyl ester, stearyl ester, phenyl ester, and the like.
The amount of the catalyst used is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, relative to 100% by mass of the total mass of the raw materials of the polyamide (A). 0% by mass or less, and more preferably 0.5% by mass or less. If the amount of the catalyst used is at least the above lower limit, the polymerization proceeds satisfactorily. If the content is not more than the above upper limit, catalyst-derived impurities are less likely to occur, and for example, when the polyamide composition is made into a film, problems caused by the above impurities can be prevented.

[Organic heat stabilizer (B)]
As the organic heat stabilizer (B) contained in the polyamide composition of the present invention, known compounds can be used, but phenol heat stabilizer (B1), phosphorus heat stabilizer (B2), sulfur It is preferably at least one selected from the group consisting of a thermal stabilizer (B3) and an amine thermal stabilizer (B4).

・Phenolic heat stabilizer (B1)
Examples of the phenolic heat stabilizer (B1) include hindered phenol compounds. Hindered phenol compounds have the property of imparting heat resistance and light resistance to resins such as polyamide.
Hindered phenol compounds include, for example, 2,2-thio-diethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexane-1,6- diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide), pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-Hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide, triethylene glycol bis(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, hexamethylene methylenebis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl ) propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane, tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate , 3,5-di-tert-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl ) benzene, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid and the like.

The phenolic heat stabilizer (B1) may be used alone or in combination of two or more. In particular, from the viewpoint of improving heat resistance, 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2, 4,8,10-tetraoxaspiro[5.5]undecane is preferred.
When using a phenolic heat stabilizer (B1), its content is preferably 0.01 to 2 parts by mass, more preferably 0.1 to 1 part by mass, relative to 100 parts by mass of the polyamide (A) is. Within the above range, the heat resistance can be further improved.

- Phosphorus heat stabilizer (B2)
Examples of the phosphorus heat stabilizer (B2) include monosodium phosphate, disodium phosphate, trisodium phosphate, sodium phosphite, calcium phosphite, magnesium phosphite, manganese phosphite, and pentaerythritol-type phosphite. compound, trioctylphosphite, trilaurylphosphite, octyldiphenylphosphite, trisisodecylphosphite, phenyldiisodecylphosphite, phenyldi(tridecyl)phosphite, diphenylisooctylphosphite, diphenylisodecylphosphite, diphenyl(tridecyl ) phosphite, triphenylphosphite, trioctadecylphosphite, tridecylphosphite, tri(nonylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, tris(2,4-di -tert-butyl-5-methylphenyl)phosphite, tris(butoxyethyl)phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenyl-tetratridecyl)diphosphite, tetra(C12 -C15 mixed alkyl)-4,4'-isopropylidenediphenyl diphosphite, 4,4'-isopropylidenebis(2-tert-butylphenyl).di(nonylphenyl)phosphite, tris(biphenyl)phosphite, Tetra(tridecyl)-1,1,3-tris(2-methyl-5-tert-butyl-4-hydroxyphenyl)butanediphosphite, Tetra(tridecyl)-4,4'-butylidenebis(3-methyl-6 -tert-butylphenyl) diphosphite, tetra(C1-C15 mixed alkyl)-4,4'-isopropylidene diphenyl diphosphite, tris(mono, di-mixed nonylphenyl) phosphite, 4,4'-isopropylidene bis( 2-tert-butylphenyl)・di(nonylphenyl)phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tris(3,5-di-tert-butyl- 4-hydroxyphenyl)phosphite, hydrogenated 4,4'-isopropylidenediphenylpolyphosphite, bis(octylphenyl) bis(4,4'-butylidenebis(3-methyl-6-tert-butylphenyl)) · 1,6-hexanol diphosphite, hexatridecyl-1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) diphosphite, tris (4,4'-isopropylidene bis ( 2-tert-butylphenyl)) phosphite, tris(1,3-stearoyloxyisopropyl)phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite, 2,2-methylenebis (3-methyl-4,6-di-tert-butylphenyl)-2-ethylhexylphosphite, tetrakis(2,4-di-tert-butyl-5-methylphenyl)-4,4'-biphenylene diphosphite , tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylene diphosphite, 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2 , 4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]-dioxaphosphepin and the like.

The phosphorus heat stabilizer (B2) may be used alone or in combination of two or more. As the phosphorus-based heat stabilizer (B2), a pentaerythritol-type phosphite compound and tris(2,4-di-tert-butylphenyl)phosphite are preferable from the viewpoint of further improving heat resistance.

Examples of the pentaerythritol type phosphite compound include 2,6-di-tert-butyl-4-methylphenyl phenyl pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl methyl・Pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl・2-ethylhexyl・pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl・isodecyl・penta Erythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl lauryl pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl isotridecyl pentaerythritol diphosphite , 2,6-di-tert-butyl-4-methylphenyl stearyl pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl cyclohexyl pentaerythritol diphosphite, 2,6 -di-tert-butyl-4-methylphenyl benzyl pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl ethyl cellosolve pentaerythritol diphosphite, 2,6-di- tert-butyl-4-methylphenyl butyl carbitol pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl octylphenyl pentaerythritol diphosphite, 2,6-di-tert -Butyl-4-methylphenyl nonylphenyl pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert- Butyl-4-ethylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl 2,6-di-tert-butylphenyl pentaerythritol diphosphite, 2,6-di -tert-butyl-4-methylphenyl 2,4-di-tert-butylphenyl pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl 2,4-di-tert- Octylphenyl pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl 2-cyclohexylphenyl pentaerythritol diphosphite, 2,6-di-tert-amyl-4-methylphenyl Phenyl pentaerythritol diphosphite, bis(2,4-dicumylphenyl) pentaerythritol diphosphite, bis(2,6-di-tert-amyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-octyl-4-methylphenyl)pentaerythritol diphosphite and the like. These may be used individually by 1 type, and may use 2 or more types together.

Among them, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert -butyl-4-ethylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-amyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-octyl-4 -methylphenyl)pentaerythritol diphosphite is preferred, and bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is more preferred.

When using a phosphorus-based heat stabilizer (B2), its content is preferably 0.01 to 2 parts by mass, more preferably 0.1 to 1 part by mass, relative to 100 parts by mass of the polyamide (A) is. Within the above range, the heat resistance can be further improved.

・Sulfur-based heat stabilizer (B3)
Examples of the sulfur-based heat stabilizer (B3) include distearyl 3,3'-thiodipropionate, pentaerythrityl tetrakis(3-laurylthiopropionate), 2-mercaptobenzimidazole, didodecyl 3,3'- thiodipropionate, ditridecyl 3,4'-thiodipropionate, 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediyl ester and the like.

The sulfur-based heat stabilizer (B3) may be used alone or in combination of two or more.
When using a sulfur-based heat stabilizer (B3), its content is preferably 0.02 to 4 parts by mass, more preferably 0.2 to 2 parts by mass, relative to 100 parts by mass of the polyamide (A). is. Within the above range, the heat resistance can be further improved.

- Amine heat stabilizer (B4)
Examples of the amine-based heat stabilizer (B4) include 4,4′-bis(α,α-dimethylbenzyl)diphenylamine (“Nocrac CD” manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.), N,N′-di- 2-naphthyl-p-phenylenediamine (“Nocrac White” manufactured by Ouchi Shinko Chemical Industry Co., Ltd., etc.), N,N′-diphenyl-p-phenylenediamine (“Nocrac DP” manufactured by Ouchi Shinko Chemical Industry Co., Ltd., etc.) , N-phenyl-1-naphthylamine (manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. "Noclac PA" etc.), N-phenyl-N'-isopropyl-p-phenylenediamine (manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. "Noclac 810- NA” etc.), N-phenyl-N′-(1,3-dimethylbutyl)-p-phenylenediamine (manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. “Nocrac 6C” etc.), N-phenyl-N′-(3 -Methacryloyloxy-2-hydroxypropyl)-p-phenylenediamine (such as "Nocrac G-1" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.), 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4- Stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(phenylacetoxy)-2,2,6,6-tetramethylpiperidine , 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-methoxy-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine , 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine , 4-(ethylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine, 4-(cyclohexylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine, 4-(phenylcarbamoyloxy)-2 , 2,6,6-tetramethylpiperidine, bis(2,2,6,6-tetramethyl-4-piperidyl) carbonate, bis(2,2,6,6-tetramethyl-4-piperidyl) oxalate, bis (2,2,6,6-tetramethyl-4-piperidyl)malonate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl- 4-piperidyl)adipate, bis(2,2,6,6-tetramethyl-4-piperidyl)terephthalate, 1,2-bis(2,2,6,6-tetramethyl-4-piperidyloxy)ethane, α , α'-bis(2,2,6,6-tetramethyl-4-piperidyloxy)-p-xylene, bis(2,2,6,6-tetramethyl-4-piperidyl)tolylene-2,4- Dicarbamate, bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylene-1,6-dicarbamate, tris(2,2,6,6-tetramethyl-4-piperidyl)benzene-1 , 3,5-tricarboxylate, tris(2,2,6,6-tetramethyl-4-piperidyl)benzene-1,3,4-tricarboxylate, 1-[2-{3-(3,5 -di-tert-butyl-4-hydroxyphenyl)propionyloxy}butyl]-4-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]2,2,6,6- Tetramethylpiperidine, 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and β,β,β',β'-tetramethyl-3,9- Examples thereof include condensation products with [2,4,8,10-tetraoxaspiro[5.5]undecane]diethanol.

The amine heat stabilizer (B4) may be used alone or in combination of two or more.
When using the amine-based heat stabilizer (B4), its content is preferably 0.01 to 2 parts by mass, more preferably 0.1 to 1 part by mass, relative to 100 parts by mass of the polyamide (A). is. Within the above range, the heat resistance can be further improved.

The polyamide composition of the present invention preferably contains 0.05 parts by mass or more and 5 parts by mass or less of the above-described organic heat stabilizer (B) with respect to 100 parts by mass of polyamide (A), and 0.1 mass parts Part or more and 3 parts by mass or less are more preferably contained. If the content of the organic heat stabilizer (B) is within the above range, the heat resistance of the polyamide composition can be further improved. When using a plurality of types of organic heat stabilizers (B), the total amount thereof should be within the above range.

[Other additives]
The polyamide composition may optionally contain other additives in addition to the polyamide (A) and the organic heat stabilizer (B) described above.

Other additives include, for example, stabilizers such as copper compounds; colorants; ultraviolet absorbers; light stabilizers; antistatic agents; Inorganic or organic fibrous filling such as glass fiber, carbon fiber, wholly aromatic polyamide fiber, etc. Powdery fillers such as wollastonite, silica, silica-alumina, alumina, titanium dioxide, potassium titanate, magnesium hydroxide, molybdenum disulfide, carbon nanotubes, graphene, polytetrafluoroethylene, ultra-high molecular weight polyethylene; flaky fillers such as talcite, glass flakes, mica, clay, montmorillonite and kaolin; and impact modifiers such as α-olefin copolymers and rubbers.

The above fibrous filler may be surface-treated with a silane coupling agent, a titanate-based coupling agent, or the like, if necessary. Examples of the silane coupling agent include, but are not limited to, aminosilane-based agents such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane. Coupling agents; mercaptosilane-based coupling agents such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane; epoxysilane-based coupling agents; and vinylsilane-based coupling agents. These silane coupling agents may be used individually by 1 type, and may use 2 or more types together. Among the above silane coupling agents, aminosilane coupling agents are preferred.

The fibrous filler may be treated with a sizing agent, if necessary. As the sizing agent, for example, a copolymer containing, as structural units, a carboxylic anhydride-containing unsaturated vinyl monomer unit and an unsaturated vinyl monomer unit excluding the carboxylic anhydride-containing unsaturated vinyl monomer, Examples include epoxy compounds, polyurethane resins, homopolymers of acrylic acid, copolymers of acrylic acid and other copolymerizable monomers, and salts of these with primary, secondary or tertiary amines. These sizing agents may be used alone or in combination of two or more.

The content of the other additives is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 0.02 to 200 parts by weight, preferably 0.03 to 100 parts by weight, based on 100 parts by weight of the polyamide (A). Parts by mass are more preferred.

The polyamide composition of the present invention preferably has a tensile breaking strength of 70 MPa or more, more preferably 80 MPa or more, and more preferably 90 MPa or more at 23° C. when injection-molded into a test piece having a thickness of 4 mm. More preferably, it may be 100 MPa or more. The tensile strength at break can be specifically determined by the method described in Examples.

The polyamide composition of the present invention has a heat distortion temperature of preferably 130° C. or higher, more preferably 140° C. or higher, and more preferably 145° C. or higher when injection molded into a test piece having a thickness of 4 mm. More preferably, it may be 150° C. or higher. The heat distortion temperature can be specifically determined by the method described in the Examples.

After the polyamide composition of the present invention is injection molded into a test piece with a thickness of 4 mm, the water absorption after immersing it in water at 23° C. for 168 hours is 0.4 based on the weight of the test piece before immersion. % or less, more preferably 0.3% or less, even more preferably 0.28% or less, 0.27% or less, or even 0.26% or less. . The water absorption can be determined more specifically by the method described in the Examples.

The polyamide composition of the present invention was injection-molded into a 4 mm-thick test piece, which was placed in an antifreeze solution (aqueous solution obtained by diluting twice the "super long life coolant" (pink) manufactured by Toyota Motor Corporation) at 130 ° C. The retention rate of the tensile breaking strength after immersion for 500 hours is preferably 50% or more, more preferably 80% or more, 90% or more, 95% or more, based on the tensile breaking strength before immersion. , or even 98% or more. More specifically, the retention rate of the tensile strength at break can be obtained by the method described in the Examples.

After the polyamide composition of the present invention is injection molded into a test piece having a thickness of 2 mm, the retention rate of the tensile breaking strength after standing in a dryer at 120 ° C. for 500 hours is based on the tensile breaking strength before standing. , is preferably 80% or more, more preferably 90% or more, 95% or more, 98% or more, or even 100%. More specifically, the retention rate of the tensile strength at break can be obtained by the method described in the Examples.

[Method for producing polyamide composition]
The method for producing the polyamide composition is not particularly limited, and a method capable of uniformly mixing the polyamide (A), the organic heat stabilizer (B), and the above-mentioned other additives used as necessary is preferable. can be adopted. For mixing, a method of melt-kneading using a single-screw extruder, twin-screw extruder, kneader, Banbury mixer, or the like is preferably adopted. Although the melt-kneading conditions are not particularly limited, for example, a method of melt-kneading for about 1 to 30 minutes at a temperature range about 10 to 50° C. higher than the melting point of the polyamide (A) can be mentioned.

<Molded product>
(Molding method)
A molded article made of the polyamide composition of the present invention can be produced by using the polyamide composition of the present invention through injection molding, blow molding, extrusion molding, compression molding, stretch molding, vacuum molding, foam molding, It can be obtained by molding by various molding methods such as a rotational molding method, an impregnation method, a laser sintering method, and a hot-melt lamination method. Furthermore, the polyamide composition of the present invention and other polymers can be composite-molded to obtain molded articles.

(Application)
Examples of the molded products include films, sheets, tubes, pipes, gears, cams, various housings, rollers, impellers, bearing retainers, spring holders, clutch parts, chain tensioners, tanks, wheels, connectors, switches, sensors, and sockets. , capacitors, hard disk components, jacks, fuse holders, relays, coil bobbins, resistors, IC housings, LED reflectors, etc.
In particular, the polyamide composition of the present invention is suitable for injection molded parts, heat-resistant films, tubes for transporting various drugs/medical solutions, intake pipes, blow-by tubes, substrates for 3D printers, etc., which require high-temperature properties and chemical resistance. In addition, it can be suitably used for automotive molded products that require high heat resistance and chemical resistance, such as automotive interior and exterior parts, engine room parts, cooling system parts, sliding parts, electrical parts, etc. can be done. In addition, the polyamide composition of the present invention can be made into a molded article that requires heat resistance corresponding to the surface mounting process. Such molded products include electric and electronic parts, surface mount connectors, sockets, camera modules, power supply parts, switches, sensors, capacitor base plates, hard disk parts, relays, resistors, fuse holders, coil bobbins, ICs. It can be suitably used for surface mount components such as housings.

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to these.

Each evaluation in Production Examples, Examples, and Comparative Examples was performed according to the methods shown below.
• Intrinsic Viscosity The intrinsic viscosity (dl/g) of the polyamide (sample) obtained in the Production Example at a concentration of 0.2 g/dl and a temperature of 30° C. using concentrated sulfuric acid as a solvent was obtained from the following relational expression.
η _inh =[ln(t ₁ /t ₀ )]/c
In the above relational expression, η _inh represents the intrinsic viscosity (dl / g), t ₀ represents the flow time (seconds) of the solvent (concentrated sulfuric acid), t ₁ represents the flow time (seconds) of the sample solution, and c represents the concentration (g/dl) of the sample in the sample solution (ie 0.2 g/dl).

-Melting point and glass transition temperature The melting point and glass transition temperature of the polyamides obtained in Production Examples were measured using a differential scanning calorimeter "DSC7020" manufactured by Hitachi High-Tech Science Co., Ltd.
The melting point was measured according to ISO11357-3 (2nd edition, 2011). Specifically, in a nitrogen atmosphere, the sample (polyamide) was heated from 30 ° C. to 340 ° C. at a rate of 10 ° C./min, held at 340 ° C. for 5 minutes to completely melt the sample, and then heated to 10 ° C. /min to 50°C and held at 50°C for 5 minutes. The peak temperature of the melting peak that appears when the temperature is again raised to 340°C at a rate of 10°C/min is the melting point (°C), and if there are multiple melting peaks, the peak temperature of the highest melting peak is the melting point (°C). bottom.
The glass transition temperature (° C.) was measured according to ISO 11357-2 (2nd edition, 2013). Specifically, in a nitrogen atmosphere, the sample (polyamide) was heated from 30 ° C. to 340 ° C. at a rate of 20 ° C./min, held at 340 ° C. for 5 minutes to completely melt the sample, and then heated to 20 ° C. /min to 50°C and held at 50°C for 5 minutes. The temperature at the inflection point when the temperature was again raised to 200°C at a rate of 20°C/min was taken as the glass transition temperature (°C).

<<Preparation of test piece>>
Using an injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. (clamping force: 100 tons, screw diameter: φ32 mm), using the polyamide compositions obtained in Examples and Comparative Examples, the melting point of polyamide The cylinder temperature is 20 to 30 ° C higher, the polyamide compositions of Examples 1 to 5 and Comparative Examples 1 and 5 under the condition of a mold temperature of 160 ° C., and the polyamide compositions of Comparative Examples 2 to 4 have a mold temperature of 140 ° C. Under the conditions, the polyamide composition is molded using a T runner mold, and a multi-purpose test piece type A1 (dumbbell-shaped test piece described in JIS K7139; 4 mm thickness, total length 170 mm, parallel part length 80 mm, parallel part width 10 mm).

・ Tensile breaking strength Using the multi-purpose test piece type A1 (4 mm thickness) prepared by the above method, Autograph (manufactured by Shimadzu Corporation) is used in accordance with ISO527-1 (2012 2nd edition). Then, the tensile strength at break (MPa) at 23°C was measured.

・Chemical resistance (tensile strength retention rate)
Using the multi-purpose test piece type A1 (4 mm thick) prepared by the above method, a tensile test is performed at 23 ° C. according to ISO 527-1 (2nd edition, 2012), and the tensile breaking strength is calculated from the following formula (1). bottom. This value was defined as the initial tensile strength at break (a).
Tensile strength at break (MPa)=stress at break (N)/cross-sectional area of test piece (mm ² ) (1)
The test piece prepared by the above method is immersed in an antifreeze solution (an aqueous solution obtained by diluting twice the "super long life coolant" (pink) manufactured by Toyota Motor Corporation) in a pressure container, and the pressure container is set to 130 ° C. It was allowed to stand for 500 hours in a constant temperature bath ("DE-303" manufactured by Mita Sangyo Co., Ltd.). After 500 hours, the test piece was taken out from the constant temperature bath and subjected to a tensile test in the same manner as described above, and the tensile breaking strength (b) of the heated test piece was measured.
The tensile strength retention rate was obtained from the following formula (2), and the long-term heat and chemical resistance was evaluated.
Tensile strength retention (%) = {(b)/(a)} x 100 (2)

· Heat distortion temperature A test piece (4 mm thick, total length 80 mm, width 10 mm) is prepared by cutting from the multi-purpose test piece type A1 (4 mm thick) prepared by the above method, and an HDT tester manufactured by Toyo Seiki Seisakusho Co., Ltd. S-3M” was used to measure the heat distortion temperature (° C.) in accordance with ISO75 (3rd edition, 2013).

- Water absorption A multi-purpose test piece type A1 (4 mm thick) prepared by the above method was weighed. Then, it was immersed in water, and after immersion treatment at 23° C. for 168 hours, it was weighed again to obtain the amount of weight increase, which was divided by the weight before immersion to obtain the water absorption (%).

· Heat aging resistance Using a small kneader / injection molding machine ("Xplore MC15") manufactured by Xplore Instruments, using the polyamide compositions obtained in Examples and Comparative Examples, the melting point of the polyamide is 20 to 30 ℃ high cylinder temperature, mold the polyamide composition using a T-runner mold under the conditions of 170 ℃, small test piece type 1BA (2 mm thickness, total length 75 mm, parallel part length 30 mm, parallel part width 5 mm) were produced. The tensile strength of this small test piece type 1BA (2 mm thick) after standing in a dryer at 120 ° C. for 500 hours was measured according to ISO527-1 (2nd edition of 2012), and before standing in the dryer By calculating the ratio (%) to the tensile strength of the test piece, it was used as an index of heat aging resistance.

Components used to prepare polyamide compositions in Examples and Comparative Examples are shown.

"polyamide"
[Production Example 1]
・Production of semi-aromatic polyamide (PA9N-1) 2,6-naphthalene dicarboxylic acid 9110.2 g (42.14 mol), a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine [former/ The latter = 4/96 (molar ratio)] 6853.7 g (43.30 mol), 210.0 g (1.72 mol) of benzoic acid, 16.2 g of sodium hypophosphite monohydrate (to the total mass of raw materials 0.1% by mass of the content) and 8.3 liters of distilled water were placed in an autoclave having an internal volume of 40 liters, and the autoclave was purged with nitrogen. The mixture was stirred at 100°C for 30 minutes, and the temperature inside the autoclave was raised to 220°C over 2 hours. At this time, the pressure inside the autoclave increased to 2 MPa. Heating was continued for 5 hours while maintaining the pressure at 2 MPa, and water vapor was gradually removed to allow the reaction to proceed. Next, the pressure was lowered to 1.3 MPa over 30 minutes, and the reaction was continued for 1 hour to obtain a prepolymer. The resulting prepolymer was dried at 100° C. under reduced pressure for 12 hours and pulverized to a particle size of 2 mm or less. This was solid phase polymerized at 230° C. and 13 Pa (0.1 mmHg) for 10 hours to obtain a polyamide. This polyamide is abbreviated as "PA9N-1".

[Production Example 2]
・Production of semi-aromatic polyamide (PA9N-1B) Except that the amount of raw materials charged was 9175.3 g (42.44 mol) of 2,6-naphthalenedicarboxylic acid and 136.5 g (1.12 mol) of benzoic acid A polyamide was obtained in the same manner as in Production Example 1. This polyamide is abbreviated as "PA9N-1B".

[Production Example 3]
・Production of semi-aromatic polyamide (PA9N-2) A mixture with a ratio of 1,9-nonanediamine and 2-methyl-1,8-octanediamine [former/latter = 15/85 (molar ratio)] was used A polyamide was obtained in the same manner as in Production Example 1 except for the above. This polyamide is abbreviated as "PA9N-2".

[Production Example 4]
・Production of semi-aromatic polyamide (PA9N-3) A mixture with a ratio of 1,9-nonanediamine and 2-methyl-1,8-octanediamine [former/latter = 85/15 (molar ratio)] was used A polyamide was obtained in the same manner as in Production Example 1 except for the above. This polyamide is abbreviated as "PA9N-3".

[Production Example 5]
・Production of semi-aromatic polyamide (PA9T-1) As raw materials, 8190.7 g (49.30 mol) of terephthalic acid, a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine [former/latter = 4 /96 (molar ratio)] 7969.4 g (50.35 mol), 171.0 g (1.40 mol) of benzoic acid, 16.3 g of sodium hypophosphite monohydrate (0 relative to the total mass of raw materials) .1% by mass) and 5.5 liters of distilled water were used in the same manner as in Production Example 1 to obtain a polyamide. This polyamide is abbreviated as "PA9T-1".

[Production Example 6]
・Production of semi-aromatic polyamide (PA9T-2) A mixture with a ratio of 1,9-nonanediamine and 2-methyl-1,8-octanediamine [former/latter = 80/20 (molar ratio)] was used A polyamide was obtained in the same manner as in Production Example 4 except for the above. This polyamide is abbreviated as "PA9T-2".

《Organic heat stabilizer》
"SUMILIZER GA-80", "NAUGARD 445" manufactured by Sumitomo Chemical Co., Ltd., "Other additives" manufactured by ADDIVANT
・Lubricant “LICOWAX OP”, manufactured by Clariant Chemicals ・Crystal nucleating agent “TALC ML112” manufactured by Fuji Talc Co., Ltd. ・Glass fiber “CS03JA-FT2A” manufactured by Owens Corning Japan LLC ・Coloring agent carbon black “#980B” , manufactured by Mitsubishi Chemical Corporation

[Examples 1 to 5 and Comparative Examples 1 to 5]
Each component other than glass fiber is mixed in advance at the ratio shown in Table 1, and fed from the upstream hopper of a twin-screw extruder ("TEM-26SS" manufactured by Toshiba Machine Co., Ltd.), and glass fiber is used. was fed from the side feed port on the downstream side of the extruder at the ratio shown in Table 1. The mixture was melt-kneaded at a cylinder temperature 20 to 30° C. higher than the melting point of the polyamide, extruded, cooled and cut to produce a polyamide composition in the form of pellets.

Using the polyamide compositions obtained in the above Examples and Comparative Examples, the various physical properties described above were evaluated. Table 1 shows the results.
In Table 1, C9DA indicates a 1,9-nonanediamine unit and MC8DA indicates a 2-methyl-1,8-octanediamine unit.

From Table 1, it can be seen that the polyamide compositions of Examples 1-5 have higher retention of tensile strength after immersion in antifreeze solution and further improved chemical resistance as compared with Comparative Examples 1-4. Further, the polyamide compositions of Examples 1 to 5 are superior to Comparative Example 5 in heat aging resistance, and therefore have excellent high-temperature heat resistance.
In addition, the polyamide compositions of Examples 1 to 5 had equivalent or better evaluations of tensile strength at break, heat distortion temperature, and water absorption than those of Comparative Examples 1 to 5, and the polyamide composition of the present invention is also excellent in mechanical properties, heat resistance, and low water absorption.
As described in Patent Document 1, it is known that the use of an aliphatic diamine having a side chain lowers the crystallinity of the resulting polyamide, which is undesirable in terms of heat resistance, chemical resistance, and the like. . On the other hand, in the polyamide composition of the present invention, the polyamide (A) contained therein has dicarboxylic acid units mainly composed of naphthalenedicarboxylic acid units and diamine units mainly composed of branched aliphatic diamine units. By having the structure of, the chemical resistance is further improved, and in addition, various physical properties such as mechanical properties, heat resistance including high temperature heat resistance, and low water absorption are excellent.

Claims (10)

Containing a polyamide (A) having a dicarboxylic acid unit and a diamine unit and an organic heat stabilizer (B),
More than 40 mol% and 100 mol% or less of the dicarboxylic acid units are naphthalene dicarboxylic acid units,
60 mol % or more and 100 mol % or less of the diamine units are branched aliphatic diamine units and linear aliphatic diamine units as optional structural units, and the branched aliphatic diamine units and the linear aliphatic diamine The proportion of the branched aliphatic diamine unit is 60 mol% or more with respect to the total 100 mol% with the unit,
The branched aliphatic diamine unit has a methyl group as a branched chain and has 6 or more and 12 or less carbon atoms,
The linear aliphatic diamine unit has 4 or more and 12 or less carbon atoms,
The polyamide composition , wherein the polyamide (A) has a melting point of 305°C or higher . 2. The ratio of the branched aliphatic diamine unit to 100 mol % of the total of the branched aliphatic diamine unit and the linear aliphatic diamine unit is 60 mol % or more and 99 mol % or less according to claim 1 Polyamide composition. 2. The ratio of the branched aliphatic diamine unit to 100 mol % of the total of the branched aliphatic diamine unit and the linear aliphatic diamine unit is 80 mol % or more and 99 mol % or less according to claim 1 Polyamide composition. The branched aliphatic diamine unit is a diamine having the branched chain on at least one of the carbon atom at the 2-position and the carbon atom at the 3-position when the carbon atom to which any one amino group is bonded is the 1-position. The polyamide composition according to any one of claims 1 to 3 , which is a structural unit derived from. The branched aliphatic diamine units are 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2-methyl-1,8-octanediamine, and 2-methyl-1,9 - The polyamide composition according to any one of claims 1 to 4 , which is a structural unit derived from at least one diamine selected from the group consisting of nonanediamine. The linear aliphatic diamine unit is 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine , 1,10-decanediamine, 1,11 - undecanediamine, and 1,12-dodecanediamine. A polyamide composition according to any one of claims 1 to 3. The polyamide composition according to any one of claims 1 to 6 , which contains 0.05 parts by mass or more and 5 parts by mass or less of the organic heat stabilizer (B) with respect to 100 parts by mass of the polyamide (A). thing. The organic heat stabilizer (B) is a group consisting of a phenol heat stabilizer (B1), a phosphorus heat stabilizer (B2), a sulfur heat stabilizer (B3), and an amine heat stabilizer (B4). The polyamide composition according to any one of claims 1 to 7 , which is at least one selected from. A molded article made of the polyamide composition according to any one of claims 1 to 8 . 10. The molded article according to claim 9 , which is a film.

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