JP2012031393A - Polyamide resin composition and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition excellent in heat aging resistance.SOLUTION: The polyamide resin composition comprises compounding 0.05-5 pts.wt. of at least one compound (b) selected from a group consisting of a stabilizer having a hydroxyl group, a monocarboxylic acid, and an acid anhydride based on 100 pts.wt. of a polyamide resin (a) comprising monomers containing an aliphatic diamine made of tetramethylenediamine and/or pentamethylenediamine and a 6-18C dicarboxylic acid as main components.

Description

  The present invention relates to a heat-resistant composition comprising at least one selected from the group consisting of a stabilizer having a hydroxyl group, a monocarboxylic acid and an acid anhydride in a polyamide resin having tetramethylene diamine and / or pentamethylene diamine as a main constituent. The present invention relates to a polyamide resin composition having excellent aging properties.

  Polyamide resins are widely used in applications such as parts that require heat aging resistance due to their excellent thermal and mechanical properties. In addition, since the use temperature tends to increase due to recent diversification of plastic materials, there is an increasing demand for high heat aging resistance for polyamide materials.

  As a technique for improving the heat aging resistance of the polyamide resin, there is a method of blending a heat stabilizer in the polyamide resin. This method is well known in the art. For example, Non-Patent Documents 1 and 2 list a large number of inorganic heat-resistant stabilizers such as copper halides and organic heat-resistant stabilizers such as phosphites, phosphorus and sulfur, which improve heat aging resistance. Is described.

  On the other hand, a polyamide resin containing tetramethylenediamine and / or pentamethylenediamine as a main component is inferior in heat aging resistance as compared with polyamide 66 or the like composed of hexamethylenediamine, as described in Patent Document 1. It was an issue.

JP 2009-235352 A

Nylon Plastics Handbook, M.M. I. Kohan, p442-443 (1985) Pub. No. 01652.90.00.040 Ciba Specialty Chemicals, 2003

  An object of the present invention is to obtain a polyamide resin composition having improved heat aging resistance by using a polyamide resin containing tetramethylenediamine and / or pentamethylenediamine as a main constituent.

  As a result of intensive studies, the present inventor has found that ammonia produced as a by-product during the cyclization reaction of tetramethylenediamine and / or pentamethylenediamine affects the heat aging resistance. The present invention employs the following means based on such knowledge.

That is, the present invention
(1) To 100 parts by weight of a polyamide resin composed of (a) an aliphatic diamine composed of tetramethylenediamine and / or pentamethylenediamine, and a monomer containing a C6-18 dicarboxylic acid as main components (B) a polyamide resin composition comprising 0.05 to 5 parts by weight of at least one selected from the group consisting of a stabilizer having a hydroxyl group, a monocarboxylic acid and an acid anhydride,
(2) The polyamide resin composition as described in (1) above, wherein the amino terminal group concentration of the polyamide resin (a) is 8.0 × 10 ⁻⁵ mol / g or less,
(3) The dicarboxylic acid having 6 to 18 carbon atoms is at least one selected from the group consisting of adipic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, terephthalic acid and isophthalic acid. The polyamide resin composition according to the above (1) or (2),
(4) Any of (1) to (3) above, wherein the stabilizer (b) having a hydroxyl group is at least one selected from the group consisting of a phenol-based stabilizer and a polyhydric alcohol compound. A polyamide resin composition according to claim 1,
(5) The polyamide resin composition according to (4), wherein the polyhydric alcohol compound has a residue of pentaerythritol, glycerin, trimethylolethane and / or trimethylolpropane,
(6) The stabilizer (b) having a hydroxyl group is N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), triethylene glycol-bis (3 -(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate), pentaerythrityltetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate), octadecyl-3- At least one selected from the group consisting of (3,5-di-t-butyl-4-hydroxyphenyl) propionate, pentaerythritol, dipentaerythritol, tripentaerythritol, diglycerin, polyglycerin, trimethylolethane and trimethylolpropane. The seed according to any one of (1) to (5) above, which is a seed Polyamide resin composition,
(7) The polyamide resin composition according to any one of (1) to (3), wherein the (b) monocarboxylic acid is benzoic acid,
(8) Any of the above (1) to (3), wherein the (b) acid anhydride is at least one selected from the group consisting of succinic anhydride, maleic anhydride and phthalic anhydride A polyamide resin composition according to claim 1,
(9) The polyamide resin composition according to any one of (1) to (8) above, wherein (c) 1 to 200 parts by weight of a filler is further blended with 100 parts by weight of the polyamide resin.
(10) The polyamide resin according to any one of the above (1) to (8), further comprising (d) 5 to 100 parts by weight of an impact resistance improver based on 100 parts by weight of the polyamide resin. Composition,
(11) A molded article obtained by injection molding the polyamide resin composition according to any one of (1) to (10) above,
(12) At least (a) the polyamide resin, and (b) at least one selected from the group consisting of a stabilizer having a hydroxyl group, a monocarboxylic acid and an acid anhydride are melt-kneaded. A method for producing the polyamide resin composition according to any one of the above,
(13) At least (a) the monomer constituting the polyamide resin, and (b) a stabilizer having a hydroxyl group and / or a monocarboxylic acid is added to perform polycondensation according to any one of (1) to (10) above. A process for producing a polyamide resin composition of
It is.

  Since the polyamide resin composition of the present invention is excellent in heat aging resistance, it can be suitably used in electric / electronic parts and automobile parts that require heat aging resistance.

  Hereinafter, the present invention will be described in detail.

  (A) an aliphatic diamine composed of tetramethylenediamine and / or pentamethylenediamine used in the present invention, and a polyamide resin composed of a monomer containing a C6-18 dicarboxylic acid as a main component, It is a polyamide resin in which the total weight of tetramethylenediamine and / or pentamethylenediamine and a dicarboxylic acid having 6 to 18 carbon atoms is 70% by weight or more of the raw material monomer. More preferably, it is 80 weight% or more, More preferably, it is 90 weight% or more.

  Examples of the dicarboxylic acid having 6 to 18 carbon atoms include adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, Examples include heptadecanedioic acid, octadecanedioic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, 2-methylterephthalic acid, and naphthalenedicarboxylic acid. In particular, adipic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, terephthalic acid, and isophthalic acid are preferred because dicarboxylic acid is easily available and the resulting polyamide resin composition has an excellent balance of crystallinity and strength. . These may be used in combination to form a copolymer.

  (A) As copolymerized units other than aliphatic diamine composed of tetramethylenediamine and / or pentamethylenediamine and dicarboxylic acid having 6 to 18 carbon atoms constituting the polyamide resin, ethylenediamine, 1,3-diaminopropane, 1 , 6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,13 -Diaminotridecane, 1,14-diaminotetradecane, 1,15-diaminopentadecane, 1,16-diaminohexadecane, 1,17-diaminoheptadecane, 1,18-diaminooctadecane, 1,19-diaminononadecane, 1 , 20-Diaminoeicosane, 2-methyl-1,5 Aliphatic diamines such as diaminopentane, cyclohexanediamine, alicyclic diamines such as bis- (4-aminocyclohexyl) methane, aromatic diamines such as xylylenediamine, 6-aminocaproic acid, 11-aminoundecanoic acid, 12 -Aminododecanoic acid, amino acids such as paraaminomethylbenzoic acid, lactams such as ε-caprolactam, ω-laurolactam, aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, etc. At least one kind can be contained in an amount of less than 30% by weight based on the total components.

  (A) As a method for producing the polyamide resin used in the present invention, tetramethylenediamine and / or pentamethylenediamine and a dicarboxylic acid having 6 to 18 carbon atoms or a salt thereof are heated to synthesize a low-order condensate. A method of increasing the degree of polymerization through solid-phase polymerization or melt polymerization through the steps may be mentioned. This method includes two-stage polymerization in which a low-order condensate is once taken out, followed by solid-phase polymerization or melt polymerization, and one-stage polymerization in which solid-phase polymerization or melt polymerization is performed in the same reaction vessel following the production process of the low-order condensate Either of these may be used. The polyamide resin obtained by melt polymerization has a narrow molecular weight distribution compared to the polyamide resin obtained by solid phase polymerization, and the content of relatively low molecular weight components is relatively small. The mechanical properties are improved, which is more preferable. The low-order condensate is defined as a polyamide resin having a sulfuric acid relative viscosity described later of 1.05-1.90. The solid phase polymerization is a step of heating in a temperature range of 100 ° C. to a melting point under reduced pressure or in an inert gas, and the melt polymerization is a step of heating to a melting point or higher under normal pressure or reduced pressure. .

When producing a polyamide resin for use in the present invention, tetramethylene diamine, pentamethylene diamine, and pyrrolidine and piperidine produced by the cyclization reaction thereof are volatilized, and pyrrolidine and piperidine are used as end-capping agents. As the polymerization proceeds, the total amino group amount with respect to the total carboxyl group amount decreases in the polymerization system, and the polymerization rate tends to be delayed. In the present invention, in order to suppress the volatilization of tetramethylenediamine and / or pentamethylenediamine, it is preferable that the pressure in the polymerization system is high. On the other hand, if the volatilization of condensed water is suppressed, tetramethylenediamine and Since the cyclization reaction of pentamethylenediamine tends to be promoted, it is preferable in the present invention that the maximum pressure in the polymerization system is 1 to 25 kg / cm ² (0.10 to 2.45 MPa). More preferably, it is 2-20 kg / cm < ² > (0.20-1.96 MPa), More preferably, it is 2-15 kg / cm < ² > (0.20-1.47 MPa), Most preferably, 2-10 kg / cm < ² > (0. 20 to 0.98 MPa). When the pressure is less than 1 kg / cm ² (0.10 MPa), the volatilization of tetramethylene diamine and / or pentamethylene diamine cannot be sufficiently suppressed, and the equimolarity of the amino group and carboxyl group is greatly lost. Tend. Further, when the pressure exceeds 25 kg / cm ² (2.45 MPa), water desorption due to polycondensation is suppressed, and the cyclization reaction of tetramethylenediamine and / or pentamethylenediamine is promoted. There is a tendency for the degree of polymerization to hardly increase. Condensation water is generated by the progress of the condensation reaction, and the pressure in the system rises. Therefore, the pressure at the start of polymerization may be zero, but when the volatilization of tetramethylenediamine and / or pentamethylenediamine is suppressed to a minimum The pressure in the system can be adjusted to be high by a method of adding water to the raw material in advance or a method of pressurizing with an inert gas in advance at the start of polymerization.

  In addition, at the stage of charging the raw material, a specific amount of tetramethylenediamine and / or pentamethylenediamine may be added in advance to control the amount of amino groups in the polymerization system. Preferred for obtaining. When the number of moles of tetramethylenediamine and / or pentamethylenediamine used as a raw material is A and the number of moles of dicarboxylic acid having 6 to 18 carbon atoms is B, the ratio A / B is 1.001 to 1.08. It is preferable to adjust the raw material composition ratio so that the raw material composition ratio is adjusted to 1.005 to 1.05. When A / B is less than 1.001, the total amino group amount in the polymerization system is extremely smaller than the total carboxyl group amount, and it tends to be difficult to obtain a high molecular weight polymer. On the other hand, when A / B is larger than 1.08, the total amount of carboxyl groups in the polymerization system is extremely smaller than the total amount of amino groups, and it tends to be difficult to obtain a high molecular weight polymer. Furthermore, the volatilization amount of the diamine component increases, which is not preferable from the viewpoint of productivity and environment.

  In the heat polycondensation for producing the polyamide resin used in the present invention, in addition to volatilization of tetramethylene diamine and / or pentamethylene diamine and suppression of cyclization by deammonia reaction, in order to prevent coloring, It is important to minimize the thermal history received by the polymer throughout the polymerization process, and it is effective to lower the maximum temperature within the polymerization system as a means for this. In the present invention, when the low-order condensate is melt-polymerized, the maximum temperature reached in the polymerization system is preferably not less than the melting point of the polyamide resin and not more than 340 ° C., more preferably not less than the melting point and the melting point + 30 ° C. or less. It is. When the temperature is higher than 340 ° C., volatilization and cyclization of tetramethylenediamine and / or pentamethylenediamine are promoted, and the resulting polyamide resin tends to be colored. In the case of increasing the degree of polymerization in the solid phase, it is preferable to perform solid phase polymerization at a melting point of −40 ° C. or higher and lower than the melting point under reduced pressure or in an inert gas atmosphere.

  The degree of polymerization of the polyamide resin (a) used in the present invention is preferably such that the relative viscosity at 25 ° C. of a 98% sulfuric acid solution of 0.01 g / ml is 1.8 to 5.0. More preferably, it is 2.2-4.5, More preferably, it is 2.5-4.0. If the relative viscosity is less than 1.8, the toughness of the polyamide resin tends to decrease. On the other hand, if the relative viscosity exceeds 5.0, the moldability tends to be inferior.

The (a) polyamide resin used in the present invention has a tetramethylenediamine moiety at the end of the polyamide chain and / or pentamethylene by a heat treatment at 100 ° C. to a melting point or lower as compared with a polyamide resin having hexamethylenediamine as a main diamine component. A cyclization reaction of the diamine moiety is likely to occur, and ammonia is produced as a by-product by this cyclization reaction. Further, ammonia is also produced as a by-product by a cyclization reaction of tetramethylene diamine and / or pentamethylene diamine generated with the decomposition of the polyamide resin. In other words, ammonia tends to be generated as a by-product as compared with a polyamide resin containing hexamethylenediamine as a main diamine component. In the present invention, from the viewpoint of suppressing the by-production of ammonia accompanying the cyclization reaction of the terminal diamine during heat treatment, the amino terminal group concentration of the (a) polyamide resin is 8.0 × 10 ⁻⁵ mol / g or less. It is preferable. By setting the amino terminal group concentration to 8.0 × 10 ⁻⁵ mol / g or less, the heat aging resistance can be further improved. More preferably, it is 6.0 × 10 ⁻⁵ mol / g or less, and further preferably 5.0 × 10 ⁻⁵ mol / g or less. The amino terminal group concentration of the polyamide resin can be calculated, for example, by dissolving the polyamide resin in a solvent and titrating with a hydrochloric acid aqueous solution or the like.

  In order to adjust the amino terminal group concentration within the above range, for example, it is preferable to adjust the raw material composition ratio of tetramethylenediamine and / or pentamethylenediamine used as a raw material to a dicarboxylic acid having 6 to 18 carbon atoms.

  If necessary, a polymerization accelerator can be added to the polyamide resin used in the present invention. As the polymerization accelerator, for example, phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, polyphosphoric acid and inorganic phosphorus compounds such as alkali metal salts and alkaline earth metal salts thereof are preferable, and sodium phosphite is particularly preferable. Sodium hypophosphite is preferably used. The polymerization accelerator is preferably used in the range of 0.001 to 1 part by weight with respect to 100 parts by weight of the raw material. When the amount of the polymerization accelerator used is less than 0.001 part by weight, the addition effect is hardly recognized, and when it exceeds 1 part by weight, the degree of polymerization of the resulting polyamide resin is excessively increased. There is a tendency that melt molding becomes difficult.

  In the present invention, (a) the polyamide resin containing tetramethylene diamine and / or pentamethylene diamine as a main constituent component is subjected to a heat treatment at a temperature of 100 ° C. to a melting point or less, so that the tetramethylene diamine site at the end of the polyamide chain and / or Alternatively, ammonia is produced as a by-product in the cyclization reaction at the pentamethylenediamine site. Further, ammonia is also produced as a by-product by a cyclization reaction of tetramethylene diamine and / or pentamethylene diamine generated with the decomposition of the polyamide resin. It is considered that this ammonia promotes the decomposition of the polyamide resin and decreases the heat aging resistance. In the present invention, the heat aging resistance can be improved by capturing ammonia produced as a by-product during heat treatment or reducing the amino end group concentration to reduce the amount of ammonia produced as a by-product. Therefore, in this invention, it is necessary to mix | blend at least 1 sort (s) chosen from the group which consists of the stabilizer which has a hydroxyl group, monocarboxylic acid, and an acid anhydride. Two or more of these may be blended.

  Examples of the stabilizer (b) having a hydroxyl group used in the present invention include at least one selected from the group consisting of a phenol-based stabilizer and a polyhydric alcohol compound.

  The phenolic stabilizer is not particularly limited as long as it has a hydroxyl group, and examples thereof include hindered phenol compounds.

Examples of the hindered phenol compound include N, N′-hexane-1,6-diylbis [3- (3,5-di-t-butyl-4-hydroxyphenylpropionamide)], pentaerythrityl-tetrakis [3 -(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), tri Ethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5- Methylphenyl) propynyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxapyro [5,5] undecane, 3,5-di-t-butyl-4-hydride Xylbenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 1,3,5-tris (4- t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, reaction product of p-cresol and isobutylene, 3- (4′-hydroxy-3′-5′-di-t-butylphenyl) propion Acid-n-octadecyl, 4,4′-thiobis (6-tert-butyl-3-methylphenol), tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) Propionate] methane, 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,2-thio [diethylbis-3 3,5-di-tert-butyl-4-hydroxyphenyl) propionate], diethyl [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate, 2,4-dichlorobenzaldehyde 3,6-dioxaoctamethylene bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], o-cresol, 1-octanethiol, paraformaldehyde reaction product, 6 -Methylheptyl = 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, dichlorobis (η (5) -cyclopentadienyl) titanium (IV), 2,2'-methylenebis (6- tert-butyl) -p-cresol, styrene-phenol, 4,4′-butylidenebi (6-tert-butyl-3-methylphenol), methylenebis (nonylcresol), 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate 1,3,5-tris (3 ′, 5′-di-tert-butyl-4-hydroxybenzyl) isocyanuric acid, 6- (4-hydroxy-3-5-di-tert-butylanilino) -2,4 -Bisoctylthio-1,3,5-triazine, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, N, N'-bis-3- (3 ', 5′-di-tert-butyl-4′-hydroxyphenyl) propionylhexamethylenediamine, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphene) Nyl) propionate, 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, pentaerythrityl tetrakis (3- ( 3,5-di-tert-butyl-4-hydroxyphenyl) propionate), tris- (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate, 2,4′-bis [(octylthio) ) Methyl] -o-cresol, isooctyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, hexamethylenebis [3- (3,5-di-t-butyl-4-hydroxy) Phenyl) propionate], thiodiethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethyleneglycolbis- -(3-t-butyl-4-hydroxy-5-methylphenyl) propionate, triethylene glycol-bis (3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate) and the like. it can. Among these, preferred hindered phenol stabilizers are N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), triethylene glycol-bis (3- ( 3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate), pentaerythrityltetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3 , 5-di-t-butyl-4-hydroxyphenyl) propionate.
These phenol stabilizers may be used alone or in combination of two or more.

  The polyhydric alcohol compound is not particularly limited as long as it has two or more hydroxyl groups, and those having a residue of pentaerythritol, glycerin, trimethylolethane and / or trimethylolpropane are preferable. For example, pentaerythritol residues such as pentaerythritol, dipentaerythritol, tripentaerythritol, polypentaerythritol and their alkylene oxide adducts, trimethylolethane, trimethylolpropane, ditrimethylolpropane, tritrimethylolpropane, etc. Compounds having trimethylolethane or trimethylolpropane residues, compounds having glycerin residues such as glycerin, diglycerin, triglycerin, tetraglycerin, pentaglycerin, hexaglycerin, polyglycerin and their alkylene oxide adducts , Ethylene glycol, polyethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1, -Hexanediol, 1,10-decanediol, 1,12-dodecanediol, methyl glucoside, sorbitol, mannitol, sucrose, 1,3,5-trihydroxybenzene, anhydrous enneaheptitol, 1,2,4-butanetriol 1,2,5-pentanetriol, 1,2,6-hexanetriol, 2-methylpropanetriol, 1,2,3,6-hexanetetrol, 1,2,4-trihydroxybenzene, etc. be able to. Among these, preferred polyhydric alcohol compounds are pentaerythritol, dipentaerythritol, tripentaerythritol, diglycerin, polyglycerin, trimethylolethane and trimethylolpropane.

  By adding a stabilizer having a hydroxyl group to the polyamide resin containing (a) tetramethylene diamine and / or pentamethylene diamine as the main component in the present invention, ammonia by-produced during heat treatment can be captured.

  The blending amount of the (b) stabilizer having a hydroxyl group in the polyamide resin composition in the present embodiment is 0.05 to 5 parts by weight, preferably 0.07 with respect to 100 parts by weight of the (a) polyamide resin. -1 part by weight, more preferably 0.1-1 part by weight.

  (B) When the compounding quantity of the stabilizer which has a hydroxyl group is less than 0.05 weight part, the effect of a stabilizer is inadequate. When the amount is more than 5 parts by weight, mechanical properties such as toughness and strength may be deteriorated, which is not preferable.

  Examples of (b) monocarboxylic acids used in the present invention include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecyl acid, myristic acid, palmitic acid, stearic acid, pivalic acid, isobutyl. Aliphatic monocarboxylic acid such as acid, alicyclic monocarboxylic acid such as cyclohexanecarboxylic acid, benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, phenylacetic acid and other aromatics A monocarboxylic acid etc. can be mentioned. Of these, benzoic acid is particularly preferred from the standpoints of reactivity, stability of the sealed end, and price. In the present invention, these monocarboxylic acids may be used alone or in combination of two or more.

  In the present invention, (a) a monocarboxylic acid as a terminal blocking agent is added to a polyamide resin containing tetramethylene diamine and / or pentamethylene diamine as a main constituent component, whereby a tetramethylene diamine site at the end of the polyamide chain and / or Alternatively, the cyclization reaction at the pentamethylenediamine site can be suppressed, and ammonia by-product can be suppressed.

  The blending amount of (b) monocarboxylic acid in the polyamide resin composition in the present embodiment varies depending on the reactivity, boiling point, reaction apparatus, reaction conditions, etc. of the monocarboxylic acid used, but usually (a) polyamide resin It is 0.05-5 weight part with respect to 100 weight part, Preferably it is 0.07-3 weight part, More preferably, it is 0.08-1 weight part.

  (B) When the compounding quantity of monocarboxylic acid is less than 0.05 weight part, the effect of terminal blockage is inadequate. When the amount is more than 5 parts by weight, when monocarboxylic acid is added in the polycondensation stage of the polyamide resin, the total amino group amount is extremely smaller than the total carboxyl group amount, and it is difficult to obtain a sufficiently high molecular weight polyamide resin. Therefore, it is not preferable.

  Examples of (b) acid anhydrides used in the present invention include propionic anhydride, succinic anhydride, maleic anhydride, and phthalic anhydride. In the present invention, these acid anhydrides may be used alone or in combination of two or more.

  In the present invention, (a) an acid anhydride that functions as a terminal blocking agent is added to a polyamide resin containing tetramethylene diamine and / or pentamethylene diamine as a main constituent component, whereby a tetramethylene diamine site at the end of the polyamide chain and It is possible to suppress the cyclization reaction at the pentamethylenediamine site and / or to suppress ammonia by-product.

  The blending amount of (b) acid anhydride in the polyamide resin composition in the present embodiment is 0.05 to 5 parts by weight, preferably 0.07 to 100 parts by weight based on (a) polyamide resin. 3 parts by weight, more preferably 0.09 to 1 part by weight.

  (B) When the compounding quantity of an acid anhydride is less than 0.05 weight part, the effect of terminal blockage is inadequate. When the amount is more than 5 parts by weight, mechanical properties such as strength and rigidity may be lowered, which is not preferable.

  In the present invention, (b) at least one selected from the group consisting of a stabilizer having a hydroxyl group, a monocarboxylic acid and an acid anhydride can be used in combination with other stabilizers from the viewpoint of further improving heat aging resistance. . Examples of other stabilizers include hindered amine, phosphorus, sulfur, benzotriazole, and metal halide compounds.

  The filler (c) used in the present invention can be used in any form of organic, inorganic, fibrous filler, and non-fibrous filler. Examples of the fibrous filler include glass fiber, carbon fiber, potassium titanate whisker, zinc oxide whisker, calcium carbonate whisker, wollastonite whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, Examples thereof include gypsum fiber and metal fiber. Examples of non-fibrous fillers include non-swelling silicates such as talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, bentonite, asbestos, alumina silicate, calcium silicate, and Li-type fluorine teniolite. , Swellable layered silicate represented by swellable mica of Na-type fluorine teniolite, Na-type tetrasilicon fluorine mica, Li-type tetrasilicon fluorine mica, silicon oxide, magnesium oxide, alumina, silica, diatomaceous earth, zirconium oxide, titanium oxide Metal oxides such as iron oxide, zinc oxide, calcium oxide, tin oxide, antimony oxide, carbonates such as calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, dolomite, hydrotalcite, calcium sulfate, barium sulfate, etc. Sulfate, magnesium hydroxide Hydroxides such as calcium hydroxide, aluminum hydroxide, basic magnesium carbonate, montmorillonite, beidellite, nontronite, saponite, hectorite, soconite and other smectite clay minerals and vermiculite, halloysite, kanemite, kenyaite, zirconium phosphate, Examples include various clay minerals such as titanium phosphate, glass beads, glass flakes, ceramic beads, boron nitride, aluminum nitride, silicon carbide, calcium phosphate, carbon black, and graphite. The swellable layered silicate may be a swellable layered silicate in which exchangeable cations existing between layers are exchanged with organic onium ions, and examples of organic onium ions include ammonium ions, phosphonium ions, sulfonium ions, and the like. Can be mentioned. Moreover, these fillers can also use 2 or more types together. Among these fillers, a fibrous filler is preferable.

  Specific examples of fibrous fillers include glass fibers, PAN and pitch carbon fibers, stainless fibers, metal fibers such as aluminum fibers and brass fibers, organic fibers such as aromatic polyamide fibers, gypsum fibers, and ceramic fibers. And asbestos fibers, zirconia fibers, alumina fibers, silica fibers, titanium oxide fibers, silicon carbide fibers, rock wool, potassium titanate whiskers, silicon nitride whiskers, and whisker-like fillers. Particularly preferred are glass fiber and carbon fiber. The type of glass fiber is not particularly limited as long as it is generally used for reinforcing a resin, and can be selected from, for example, a long fiber type, a short fiber type chopped strand, a milled fiber, or the like. The filler used in the present invention has excellent mechanical strength and appearance that can be treated with a known coupling agent (eg, silane coupling agent, titanate coupling agent) on the surface. Preferred in terms of obtaining. As a coupling agent, a method in which a filler is surface-treated in advance according to a conventional method and then melt-kneaded with a polyamide resin is preferably used. However, the filler and the polyamide resin are melt-kneaded without performing a surface treatment of the filler in advance. In this case, an integral blend method in which a coupling agent is added may be used. The treatment amount of the coupling agent is preferably 0.05 to 10 parts by weight with respect to 100 parts by weight of the filler. More preferably, it is 0.1-5 weight part, Most preferably, it is 0.5-3 weight part. When the amount is less than 0.05 parts by weight, the effect of improving the mechanical properties by treating with the coupling agent is small. When the amount exceeds 10 parts by weight, the filler tends to aggregate and tends to cause poor dispersion. . The glass fiber may be coated or bundled with a thermoplastic resin such as an ethylene / vinyl acetate copolymer or a thermosetting resin such as an epoxy resin. Further, the cross section of the glass fiber is not limited to a circular, flat gourd, eyebrows, oval, ellipse, rectangle or the like, but the warp peculiar to glass fiber compounded polyamide is not limited. In order to reduce it, the flat fiber preferably has a major axis / minor axis ratio of 1.5 to 10, more preferably 2.0 to 6.0. When the ratio of major axis / minor axis is 1.5 or less, the effect of flattening the cross section is small, and when the ratio is 10 or more, it is difficult to produce the glass fiber itself.

  The amount of the filler (c) is 1 to 200 parts by weight with respect to 100 parts by weight of the polyamide resin (a) of the present invention. Preferably it is 5-150 weight part, More preferably, it is 10-100 weight part. If it is less than 1 part by weight, the effect of improving the strength and rigidity is small, and if it exceeds 200 parts by weight, the moldability may be lowered, which is not preferable.

  As the (d) impact resistance improver used in the present invention, a modified polyolefin such as a (co) polymer obtained by polymerizing an olefin compound and / or a conjugated diene compound is preferably used.

  Examples of the (co) polymer include an ethylene copolymer, a conjugated diene polymer, and a conjugated diene-aromatic vinyl hydrocarbon copolymer. Here, the ethylene-based copolymer means a copolymer of ethylene and another monomer and a multi-component copolymer, and the other monomer copolymerized with ethylene is an α having 3 or more carbon atoms. It can be selected from among olefins, non-conjugated dienes, vinyl acetate, vinyl alcohol, α, β-unsaturated carboxylic acids and derivatives thereof.

  Examples of the α-olefin having 3 or more carbon atoms include propylene, butene-1, pentene-1, 3-methylpentene-1, octacene-1, and the like, and propylene and butene-1 can be preferably used. Non-conjugated dienes include 5-methylidene-2-norbornene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, 5-propenyl-2-norbornene, 5-isopropenyl-2-norbornene, 5-crotyl Norbornene compounds such as 2-norbornene, 5- (2-methyl-2-butenyl) -2-norbornene, 5- (2-ethyl-2-butenyl) -2-norbornene, 5-methyl-5-vinylnorbornene, Dicyclopentadiene, methyltetrahydroindene, 4,7,8,9-tetrahydroindene, 1,5-cyclooctadiene 1,4-hexadiene, isoprene, 6-methyl-1,5-heptadiene, 11-tridecadiene, etc. Preferably, 5-methylidene-2-norbornene, 5-ethylidene- - norbornene, dicyclopentadiene, 1,4-hexadiene, and the like. Examples of the α, β-unsaturated carboxylic acid include acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and butenedicarboxylic acid. Derivatives thereof include alkyl esters and aryls. Examples include esters, glycidyl esters, acid anhydrides, and imides.

  The conjugated diene polymer is a polymer containing at least one conjugated diene as a constituent component. For example, a homopolymer such as 1,3-butadiene, 1,3-butadiene, isoprene (2-methyl- 1,3-butadiene), 2,3-dimethyl-1,3-butadiene, a copolymer of one or more monomers selected from 1,3-pentadiene, and the like. Those in which some or all of the unsaturated bonds of these polymers are reduced by hydrogenation can also be preferably used.

  The conjugated diene-aromatic vinyl hydrocarbon-based copolymer is a block copolymer or a random copolymer composed of a conjugated diene and an aromatic vinyl hydrocarbon. And 1,3-butadiene and isoprene are particularly preferable. Examples of the aromatic vinyl hydrocarbon include styrene, α-methyl styrene, o-methyl styrene, p-methyl styrene, 1,3-dimethyl styrene, vinyl naphthalene, and among them, styrene is preferably used. In addition, a conjugated diene-aromatic vinyl hydrocarbon copolymer in which part or all of unsaturated bonds other than double bonds other than aromatic rings are reduced by hydrogenation can be preferably used.

  Polyamide elastomers and polyester elastomers can also be used. Two or more kinds of these impact resistance improvers can be used in combination.

  In the present invention, (a) in order to improve the affinity with the polyamide resin, a glycidyl group, a carboxyl group, and a carboxyl group, which are reactive functional groups, are added to the polyolefin (co) polymer composed of the above monomers. Preferably, at least one of the above metal salts and acid anhydride groups is copolymerized or grafted. (D) These reactive functional groups contained in the impact modifier are preferably 0.1 to 7% by weight when the impact modifier is 100% by weight. More preferably, it is 0.4 to 3% by weight. When the amount is less than 0.1% by weight, (a) the affinity with the polyamide resin is inferior and the impact resistance improving effect is small. When the amount exceeds 7.0% by weight, the melt viscosity is increased and the moldability is improved. There is a tendency to be inferior.

  (D) Specific examples of the impact modifier include ethylene / propylene copolymer, ethylene / butene-1 copolymer, ethylene / hexene-1 copolymer, ethylene / propylene / dicyclopentadiene copolymer, Ethylene / propylene / 5-ethylidene-2-norbornene copolymer, unhydrogenated or hydrogenated styrene / isoprene / styrene triblock copolymer, unhydrogenated or hydrogenated styrene / butadiene / styrene triblock copolymer, ethylene / Methacrylic acid copolymers and some or all of the carboxylic acid moieties in these copolymers as salts with sodium, lithium, potassium, zinc, calcium, ethylene / methyl acrylate copolymers, ethylene / acrylic Ethyl acid copolymer, ethylene / methyl methacrylate copolymer, ethylene / methacrylic acid Chill copolymer, ethylene / ethyl acrylate-g-maleic anhydride copolymer (“g” represents graft, the same applies hereinafter), ethylene / methyl methacrylate-g-maleic anhydride copolymer, ethylene / acrylic Acid ethyl-g-maleimide copolymer, ethylene / ethyl acrylate-gN-phenylmaleimide copolymer and partially saponified products of these copolymers, ethylene / glycidyl methacrylate copolymer, ethylene / vinyl acetate / glycidyl methacrylate Copolymer, ethylene / methyl methacrylate / glycidyl methacrylate copolymer, ethylene / glycidyl acrylate copolymer, ethylene / vinyl acetate / glycidyl acrylate copolymer, ethylene / glycidyl ether copolymer, ethylene / propylene-g-anhydrous Malene Copolymer, ethylene / butene-1-g-maleic anhydride copolymer, ethylene / propylene / 1,4-hexadiene-g-maleic anhydride copolymer, ethylene / propylene / dicyclopentadiene-g-maleic anhydride Acid copolymer, ethylene / propylene / 2,5-norbornadiene-g-maleic anhydride copolymer, ethylene / propylene-gN-phenylmaleimide copolymer, ethylene / butene-1-gN-phenylmaleimide Copolymer, hydrogenated styrene / butadiene / styrene-g-maleic anhydride copolymer, hydrogenated styrene / isoprene / styrene-g-maleic anhydride copolymer, ethylene / propylene-g-glycidyl methacrylate copolymer , Ethylene / butene-1-g-glycidyl methacrylate copolymer, ethylene / propylene / 1, 4-hexadiene-g-glycidyl methacrylate copolymer, ethylene / propylene / dicyclopentadiene-g-glycidyl methacrylate copolymer, hydrogenated styrene / butadiene / styrene-g-glycidyl methacrylate copolymer, nylon 12 / Examples thereof include polytetramethylene glycol copolymer, nylon 12 / polytrimethylene glycol copolymer, polybutylene terephthalate / polytetramethylene glycol copolymer, polybutylene terephthalate / polytrimethylene glycol copolymer, and the like. Among them, ethylene / methacrylic acid copolymers and some or all of the carboxylic acid moieties in these copolymers as salts with sodium, lithium, potassium, zinc, calcium, ethylene / propylene-g-anhydrous Maleic acid copolymers, ethylene / butene-1-g-maleic anhydride copolymers, hydrogenated styrene / butadiene / styrene-g-maleic anhydride copolymers are more preferable, ethylene / methacrylic acid copolymers and these A part or all of the carboxylic acid moiety in the copolymer made into a salt with sodium, lithium, potassium, zinc, calcium, ethylene / propylene-g-maleic anhydride copolymer, ethylene / butene-1-g -Maleic anhydride copolymers are particularly preferred.

  In the present invention, the blending amount of (d) impact modifier is 5 to 100 parts by weight with respect to 100 parts by weight of (a) polyamide resin. More preferably, it is 5-50 weight part, More preferably, it is 10-40 weight part, Most preferably, it is 10-30 weight part. If the amount is less than 5 parts by weight, the effect of improving impact resistance is small, and if it exceeds 100 parts by weight, the melt viscosity tends to be high and the moldability tends to be inferior.

  The method for preparing the polyamide resin composition of the present invention is not limited to a specific method, but specific and efficient examples include (a) a polyamide resin as a raw material, (b) a stabilizer having a hydroxyl group, a monocarboxylic acid, and A compound that is at least one selected from the group consisting of acid anhydrides, and, if necessary, a mixture of (c) a filler or (d) an impact modifier, a single or twin screw extruder, a Banbury mixer, Examples thereof include a method of supplying to a known melt-kneader such as a kneader and a mixing roll and performing melt-kneading at a temperature equal to or higher than the melting point of the polyamide resin used. In the method of supplying the components constituting the polyamide resin composition to the melt kneader, all the components may be supplied to the same supply port at a time, or the components may be supplied from different supply ports. Absent.

  Alternatively, (a) a monomer constituting the polyamide resin is added (b) a stabilizer having a hydroxyl group and / or a monocarboxylic acid to perform polycondensation, and this polycondensate and, if necessary, (c) filling A method of melt kneading the material or (d) impact resistance improver with a known melt kneader is also included.

  In addition, the polyamide resin composition of the present invention can contain other polyamide resins and other polymers depending on the required properties within a range that does not impair the object of the present invention. Specific examples of other polyamide resins include polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebamide (nylon 610), polyhexamethylene dodecamide (nylon 612), Polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (nylon 66 / 6T), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6T / 6I), polyhexa Examples include methylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 6T / 6I), polyxylylene adipamide (nylon XD6), and mixtures or copolymers thereof. Specific examples of the other polymers include polyethylene, polypropylene, polyester, polycarbonate, polyphenylene ether, polyphenylene sulfide, liquid crystal polymer, polysulfone, polyethersulfone, ABS resin, SAN resin, and polystyrene.

  Further, the polyamide resin composition of the present invention includes other components such as release agents and lubricants (aliphatic alcohols, aliphatic amides, aliphatic bisamides, bisureas, polyethylene waxes, etc.) within a range not impairing the object of the invention. ), Pigment (cadmium sulfide, phthalocyanine, carbon black, etc.), dye (nigrosine, aniline black, etc.), plasticizer (octyl p-oxybenzoate, N-butylbenzenesulfonamide, etc.), antistatic agent (alkyl sulfate anion) Antistatic agent, quaternary ammonium salt type cationic antistatic agent, nonionic antistatic agent such as polyoxyethylene sorbitan monostearate, betaine amphoteric antistatic agent, etc.), flame retardant (melamine cyanurate, water) Hydroxides such as magnesium oxide and aluminum hydroxide, ammonium polyphosphate Phosphorus, flame retardants such as melamine polyphosphate, metal phosphinates, brominated polystyrene, brominated polyphenylene oxide, brominated polycarbonate, brominated epoxy resins or combinations of these brominated flame retardants with antimony trioxide) Can be added at any time.

  The polyamide resin composition thus obtained can be molded by a generally known method, and molded into a desired shape by any molding method such as injection molding, extrusion molding, blow molding, vacuum molding, melt spinning, film molding and the like. It can be used for resin molded products such as automobile parts and machine parts, fibers, films and the like. Specific applications include automotive engine coolant systems, especially radiator tank components such as radiator tank tops and bases, coolant reserve tanks, water pipes, water pump housings, water pump impellers, water pump components such as valves, and other automobiles. Parts used in contact with cooling water in the engine room, switches, micro slide switches, DIP switches, switch housings, lamp sockets, cable ties, connectors, connector housings, connector shells, IC sockets , Coil bobbin, bobbin cover, relay, relay box, condenser case, motor internal parts, small motor case, gear cam, dancing pulley, spacer, insulator, fastener, back , Wire clip, bicycle wheel, caster, helmet, terminal block, power tool housing, starter insulation, spoiler, canister, radiator tank, chamber tank, reservoir tank, fuse box, air cleaner case, air conditioner fan, terminal housing , Wheel cover, intake / exhaust pipe, bearing retainer, cylinder head cover, intake manifold, water pipe impeller, clutch release, speaker diaphragm, heat-resistant container, microwave oven part, rice cooker part, printer ribbon guide, etc. Useful in related parts, automobile / vehicle-related parts, home appliance / office electrical product parts, computer-related parts, facsimile / copier-related parts, machine-related parts, and other various applications A.

  The present invention will be described more specifically with reference to the following examples. The material properties were evaluated according to the following method.

[Sulfuric acid relative viscosity]
The relative viscosity (ηr) of the polyamide resin was measured using an Ostwald viscometer at a concentration of 0.01 g / ml in 98% sulfuric acid at 25 ° C.

[Amino end group concentration]
The amino terminal group concentration of the polyamide resins a-1 to a-7, a-10 was obtained by accurately weighing about 0.5 g of the resin and adding 25 ml of a phenol / ethanol mixed solvent (83.5: 16.5, volume ratio). After dissolution, the solution was titrated with a 0.02N hydrochloric acid aqueous solution. The amino end group concentration of the polyamide resins a-8 and 9 was determined by accurately weighing about 0.3 g of the resin, dissolving it in 15 ml of hexafluoroisopropanol solvent, and titrating with 0.02N hydrochloric acid aqueous solution.

[Tensile strength]
A tensile test was conducted on a ASTM 1 dumbbell specimen having a thickness of 1/8 inch at a crosshead speed of 10 mm / min using a tensile tester Tensilon UTA2.5T (manufactured by Orientec) according to ASTM D638. The measurement was performed three times, and the average value was calculated as the tensile strength.

[Heat resistance aging test]
An ASTM No. 1 dumbbell specimen having a thickness of 1/8 inch was heat-treated at 150 ° C. in an air atmosphere for 250 hours (heat aging resistance test treatment), and then the tensile strength was measured by the same tensile test as described above [Tensile strength]. . The measurement was performed three times, and the average value was calculated as the tensile strength. The ratio of the tensile strength after the treatment to the tensile strength before the heat aging resistance test treatment was calculated as the tensile strength retention rate.

Reference Example 1 (Production of polytetramethylene adipamide)
Nylon 46 salt 700 g, tetramethylenediamine 5.27 g, sodium hypophosphite monohydrate 0.2962 g, and ion-exchanged water 70 g were charged into a 3 L pressure vessel with a stirring blade, sealed, and purged with nitrogen. . Heating was started while the pressure vessel was sealed, and after reaching an internal temperature of 225 ° C. and 15.0 kg / cm ² , the internal pressure of the can was maintained at 15.0 kg / cm ² for 30 minutes while releasing moisture out of the system. . Thereafter, the contents were discharged from the reaction vessel onto a cooling belt. The low-order condensate obtained by vacuum drying this at 80 ° C. for 24 hours was subjected to solid phase polymerization at 260 ° C. and 100 Pa for 20 hours to obtain polytetramethylene adipamide (nylon 46, ηr = 3.10). . The amino end group concentration was 2.4 × 10 ⁻⁵ mol / g.

Reference Example 2 (Production of polytetramethylene sebacamide)
Nylon 410 salt 700 g, tetramethylenediamine 2.12 g (1.00 mol% with respect to nylon 410 salt), sodium hypophosphite 0.3065 g (0.05 wt% with respect to the weight of the produced polymer) in a 3 L pressure vessel Charged and sealed, and purged with nitrogen. After heating was started and the internal pressure of the can reached 5.0 kg / cm ² , the internal pressure of the can was maintained at 5.0 kg / cm ² for 1.5 hours while releasing moisture out of the system. Thereafter, the internal pressure of the can was returned to normal pressure over 10 minutes, and the reaction was further continued for 1.5 hours under a nitrogen flow to complete the polymerization. Thereafter, the polymer was discharged from the polymerization can in a gut shape and pelletized, and then vacuum dried at 80 ° C. for 24 hours to obtain polytetramethylene sebacamide (nylon 410, ηr = 2.84). The amino end group concentration was 3.4 × 10 ⁻⁵ mol / g.

Reference Example 3 (Production of polytetramethylene sebacamide)
Nylon 410 salt 700 g, tetramethylenediamine 4.24 g (2.00 mol% with respect to nylon 410 salt), sodium hypophosphite 0.3065 g (0.05 wt% with respect to the weight of the produced polymer) in a 3 L pressure vessel Charged and sealed, and purged with nitrogen. After heating was started and the internal pressure of the can reached 5.0 kg / cm ² , the internal pressure of the can was maintained at 5.0 kg / cm ² for 1.5 hours while releasing moisture out of the system. Thereafter, the internal pressure of the can was returned to normal pressure over 10 minutes, and the reaction was further continued for 1.5 hours under a nitrogen flow to complete the polymerization. Thereafter, the polymer was discharged from the polymerization can into a gut shape and pelletized, and this was vacuum dried at 80 ° C. for 24 hours to obtain polytetramethylene sebacamide (nylon 410, ηr = 2.55). The amino end group concentration was 9.8 × 10 ⁻⁵ mol / g.

Reference Example 4 (Production of polypentamethylene adipamide)
Into the polymerization vessel, 1500 g (3.024 mol) of a 50% by weight aqueous solution of pentamethylene adipamide salt and 46.26 g (1,5-diaminopentane content 45.26 mmol) of a 10% by weight aqueous solution of 1,5-diaminopentane were used. Then, the inside of the polymerization can was sufficiently purged with nitrogen, and then the temperature was raised while stirring. After the internal pressure of the can reached 17.5 kg / cm ² , the internal pressure of the can was maintained at 17.5 kg / cm ² for 90 minutes, and then the internal pressure of the can was returned to normal pressure over 1 hour. At this time, the temperature inside the can reached 270 ° C. Further, the polymerization was completed by reacting at 270 ° C. for 30 minutes under a reduced pressure of −160 mmHg. Thereafter, the polymer discharged into the water bath was pelletized with a strand cutter. This was vacuum-dried at 80 ° C. for 24 hours to obtain polypentamethylene adipamide (nylon 56, ηr = 2.76). The amino end group concentration was 4.2 × 10 ⁻⁵ mol / g.

Reference Example 5 (Production of polypentamethylene sebacamide)
1500 g of a 50% by weight aqueous solution of pentamethylene sebacamide salt, and 2.56 g (24.67 mmol) of 1,5-diaminopentane in excess are placed in a polymerization vessel, and the inside of the polymerization vessel is thoroughly purged with nitrogen, and then stirred. Heating started. After the can internal pressure reached 17.5 kg / cm ² , the can internal pressure was maintained at 17.5 kg / cm ² for 74 minutes, and then the can internal pressure was returned to normal pressure over 1 hour. At this time, the inside temperature of the can reached 264 ° C. The polymerization was further completed by reacting at 264 ° C. for 40 minutes under a reduced pressure of −160 mmHg. Thereafter, the polymer discharged into the water bath was pelletized with a strand cutter. This was vacuum-dried at 80 ° C. for 24 hours to obtain polypentamethylene sebacamide (nylon 510, ηr = 2.71). The amino end group concentration was 4.4 × 10 ⁻⁵ mol / g.

(Examples 1 and 2, Comparative Examples 1 and 4)
Table 1 shows the stabilizers having polytetramethylene adipamide and hydroxyl groups obtained in Reference Example 1 using a TEX30 type twin screw extruder manufactured by Nippon Steel Works with a cylinder set temperature of 310 ° C. and a screw speed of 200 rpm. After dry blending at the stated ratio, it was supplied from an extruder main feeder and melt kneaded. The gut discharged from the die was immediately cooled in a water bath and pelletized with a strand cutter. The obtained pellets were dried under reduced pressure at 80 ° C. for 12 hours, and test pieces were prepared by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, cylinder temperature 305 ° C., mold temperature 80 ° C.). The specimens before and after the heat aging resistance test were subjected to a tensile test using a tensile tester, and the tensile strength retention rate was calculated. In addition, the degree of improvement in tensile strength retention due to the addition of a stabilizer having a hydroxyl group was calculated as “strength retention after addition−non-addition strength retention” and represents a non-addition strength retention. Together with. The results are as shown in Table 1.

(Comparative Examples 2, 3, 5, 6)
Using a TEX30 twin screw extruder manufactured by Nippon Steel Works with a cylinder set temperature of 280 ° C. and a screw speed of 200 rpm, the sulfuric acid relative viscosity was 2.78 and the amino end group concentration was 3.1 × 10 ⁻⁵ mol / After being dry blended with nylon 66 resin (E3001 manufactured by Toray Industries, Inc.) and a stabilizer having a hydroxyl group at a ratio shown in Table 1, it was supplied from an extruder main feeder and melt-kneaded. The gut discharged from the die was immediately cooled in a water bath and pelletized with a strand cutter. The obtained pellets were dried under reduced pressure at 80 ° C. for 12 hours, and test pieces were prepared by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, cylinder temperature 275 ° C., mold temperature 80 ° C.). The specimens before and after the heat aging resistance test were subjected to a tensile test using a tensile tester, and the tensile strength retention rate was calculated. In addition, the degree of improvement in tensile strength retention due to the addition of a stabilizer having a hydroxyl group was calculated as “strength retention after addition−non-addition strength retention” and represents a non-addition strength retention. Together with. The results are as shown in Table 1.

(Examples 3, 5, and 6, Comparative Examples 7, 8, and 12)
Polytetramethylene sebacamide obtained in Reference Example 2 or Reference Example 3 and a stabilizer having a hydroxyl group using a TEX30 type twin screw extruder manufactured by Nippon Steel Works, set at a cylinder setting temperature of 270 ° C. and a screw rotation speed of 200 rpm A stabilizer having no hydroxyl group was dry-blended at a ratio shown in Table 1, and then supplied from an extruder main feeder and melt-kneaded. The gut discharged from the die was immediately cooled in a water bath and pelletized with a strand cutter. The obtained pellets were dried under reduced pressure at 80 ° C. for 12 hours, and test pieces were prepared by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, cylinder temperature 265 ° C., mold temperature 80 ° C.). The specimens before and after the heat aging resistance test were subjected to a tensile test using a tensile tester, and the tensile strength retention rate was calculated. Moreover, the improvement degree of the tensile strength retention by adding a stabilizer having a hydroxyl group and a stabilizer not having a hydroxyl group was calculated as "strength retention after addition-non-addition strength retention" It showed with the comparative example showing an intensity | strength retention. The results are as shown in Table 1.

(Example 4, Comparative Examples 9 and 13)
Table 1 shows the polypentamethylene sebacamide obtained in Reference Example 5 and a hydroxyl group-containing stabilizer using a TEX30 type twin screw extruder manufactured by Nippon Steel Works with a cylinder set temperature of 240 ° C. and a screw speed of 200 rpm. After dry blending at the stated ratio, it was supplied from an extruder main feeder and melt kneaded. The gut discharged from the die was immediately cooled in a water bath and pelletized with a strand cutter. The obtained pellets were dried under reduced pressure at 80 ° C. for 12 hours, and test pieces were prepared by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, cylinder temperature 240 ° C., mold temperature 80 ° C.). The specimens before and after the heat aging resistance test were subjected to a tensile test using a tensile tester, and the tensile strength retention rate was calculated. In addition, the degree of improvement in tensile strength retention due to the addition of a stabilizer having a hydroxyl group was calculated as “strength retention after addition−non-addition strength retention” and represents a non-addition strength retention. Together with. The results are as shown in Table 1.

(Comparative Examples 10, 11, 14, 15)
Using a TEX30 type twin screw extruder manufactured by Nippon Steel Works with a cylinder set temperature of 250 ° C. and a screw speed of 200 rpm, the sulfuric acid relative viscosity was 2.70 and the amino end group concentration was 3.0 × 10 ⁻⁵ mol / After dry-blending the nylon 610 resin (CM 2001 manufactured by Toray Industries, Inc.) and a stabilizer having a hydroxyl group at a ratio shown in Table 1, it was supplied from an extruder main feeder and melt-kneaded. The gut discharged from the die was immediately cooled in a water bath and pelletized with a strand cutter. The obtained pellets were dried under reduced pressure at 80 ° C. for 12 hours, and test pieces were prepared by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, cylinder temperature 245 ° C., mold temperature 80 ° C.). The specimens before and after the heat aging resistance test were subjected to a tensile test using a tensile tester, and the tensile strength retention rate was calculated. In addition, the degree of improvement in tensile strength retention due to the addition of a stabilizer having a hydroxyl group was calculated as “strength retention after addition−non-addition strength retention” and represents a non-addition strength retention. Together with. The results are as shown in Table 1.

(Examples 7 and 8, Comparative Example 16)
The polytetramethylene sebacamide, monocarboxylic acid, and acid anhydride obtained in Reference Example 2 were displayed using a TEX30 type twin screw extruder manufactured by Nippon Steel Works with a cylinder set temperature of 270 ° C. and a screw rotation speed of 200 rpm. After dry blending at the rate described in 2, supply from the main feeder of the extruder, and further filling from the side feeder installed at a position of about 0.35 when viewed from the upstream side when the total length of the screw is 1.0 The materials were supplied at the ratios shown in Table 2 and melt kneaded. The gut discharged from the die was immediately cooled in a water bath and pelletized with a strand cutter. The obtained pellets were dried under reduced pressure at 80 ° C. for 12 hours, and test pieces were prepared by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, cylinder temperature 265 ° C., mold temperature 80 ° C.). The specimens before and after the heat aging resistance test were subjected to a tensile test using a tensile tester, and the tensile strength retention rate was calculated. Further, the degree of improvement in tensile strength retention due to the addition of monocarboxylic acid and acid anhydride is calculated as “strength retention after addition−non-addition strength retention”, and represents the non-addition strength retention. It showed with the comparative example. The results are as shown in Table 2.

Example 9
In a polymerization vessel, 1500 g of a 50% by weight aqueous solution of pentamethylene sebacamide salt, 2.56 g (24.67 mmol) of 1,5-diaminopentane in excess, and 0.91 g (7.46 mmol) of benzoic acid as a monocarboxylic acid Then, the inside of the polymerization can was sufficiently purged with nitrogen, and then the temperature was raised while stirring. After the can internal pressure reached 17.5 kg / cm ² , the can internal pressure was maintained at 17.5 kg / cm ² for 74 minutes, and then the can internal pressure was returned to normal pressure over 1 hour. At this time, the inside temperature of the can reached 264 ° C. The polymerization was further completed by reacting at 264 ° C. for 40 minutes under a reduced pressure of −160 mmHg. Thereafter, the polymer discharged into the water bath was pelletized with a strand cutter. This was vacuum-dried at 80 ° C. for 24 hours to obtain polypentamethylene sebacamide (nylon 510, ηr = 2.62). The amino end group concentration was 0.6 × 10 ⁻⁵ mol / g. After dry blending the polyamide resin and the stabilizer not having a hydroxyl group in the proportions shown in Table 2, using a TEX30 type twin screw extruder manufactured by Nippon Steel Works, set at a cylinder set temperature of 240 ° C. and a screw speed of 200 rpm Supplied from the main feeder of the extruder, and further, the filler is supplied at a rate shown in Table 2 from the side feeder installed at a position of about 0.35 when viewed from the upstream side when the total length of the screw is 1.0. Then, melt kneading was performed. The gut discharged from the die was immediately cooled in a water bath and pelletized with a strand cutter. The obtained pellets were dried under reduced pressure at 80 ° C. for 12 hours, and test pieces were prepared by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, cylinder temperature 240 ° C., mold temperature 80 ° C.). The specimens before and after the heat aging resistance test were subjected to a tensile test using a tensile tester, and the tensile strength retention rate was calculated. In addition, the degree of improvement in tensile strength retention due to the addition of monocarboxylic acid was calculated as “strength retention after addition−non-added strength retention”, and shown together with a comparative example representing the non-added strength retention. It was. The results are as shown in Table 2.

(Comparative Example 17)
Table 2 shows polypentamethylene sebacamide obtained in Reference Example 5 and a stabilizer having no hydroxyl group using a TEX30 type twin screw extruder manufactured by Nippon Steel Works, set at a cylinder set temperature of 240 ° C. and a screw speed of 200 rpm. After being dry blended at the rate described in the above, it is supplied from the main feeder of the extruder, and further from the side feeder installed at a position of about 0.35 when viewed from the upstream side when the total length of the screw is 1.0, Was supplied at the ratio shown in Table 2 and melt-kneaded. The gut discharged from the die was immediately cooled in a water bath and pelletized with a strand cutter. The obtained pellets were dried under reduced pressure at 80 ° C. for 12 hours, and test pieces were prepared by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, cylinder temperature 240 ° C., mold temperature 80 ° C.). The specimens before and after the heat aging resistance test were subjected to a tensile test using a tensile tester, and the tensile strength retention rate was calculated.

(Example 10, Comparative Example 18)
800 g of equimolar salt of pentamethylene diamine and adipic acid, 800 g of equimolar salt of pentamethylene diamine and terephthalic acid, and 1.4 mol% of pentamethylene diamine based on the total amount of diamine in the salt are further added. Water was charged into the reaction vessel so that the water content was 30 wt%, sealed and purged with nitrogen. The jacket temperature was set to 300 ° C. and heating was started. After the can internal pressure reached 17.5 kg / cm ² , the can internal pressure was maintained at 17.5 kg / cm ² for 2.5 hours. Thereafter, the contents were discharged from the reaction vessel onto a cooling belt. This low-order condensate obtained by vacuum drying at 80 ° C. for 24 hours was subjected to solid phase polymerization at 240 ° C. and 0.4 torr for 10 hours to obtain a polyamide resin (nylon 5T / 56, ηr = 2.72). Got. The amino end group concentration was 2.8 × 10 ⁻⁵ mol / g. Using a TEX30 type twin screw extruder manufactured by Nippon Steel Works with a cylinder set temperature of 310 ° C. and a screw speed of 200 rpm, this polyamide resin and a stabilizer having a hydroxyl group were dry blended in the proportions shown in Table 2. Thereafter, the filler is supplied from the main feeder of the extruder, and the filler is supplied at a ratio shown in Table 2 from the side feeder installed at a position of about 0.35 when viewed from the upstream side when the total length of the screw is 1.0. Then, melt kneading was performed. The gut discharged from the die was immediately cooled in a water bath and pelletized with a strand cutter. The obtained pellets were dried under reduced pressure at 80 ° C. for 12 hours, and test pieces were prepared by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, cylinder temperature 305 ° C., mold temperature 120 ° C.). The specimens before and after the heat aging resistance test were subjected to a tensile test using a tensile tester, and the tensile strength retention rate was calculated. In addition, the degree of improvement in tensile strength retention due to the addition of a stabilizer having a hydroxyl group was calculated as “strength retention after addition−non-addition strength retention” and represents a non-addition strength retention. Together with. The results are as shown in Table 2.

(Comparative Examples 19 and 20)
800 g of equimolar salt of hexamethylene diamine and adipic acid, 800 g of equimolar salt of hexamethylene diamine and terephthalic acid, and 1.0 mol% of hexamethylene diamine with respect to the total amount of diamine in the salt, Water was charged into the reaction vessel so that the water content was 30 wt% with respect to the charged amount, sealed and purged with nitrogen. The jacket temperature was set to 300 ° C. and heating was started. After the can internal pressure reached 17.5 kg / cm ² , the can internal pressure was maintained at 17.5 kg / cm ² for 2.0 hours. Thereafter, the contents were discharged from the reaction vessel onto a cooling belt. This low-order condensate obtained by vacuum drying at 80 ° C. for 24 hours was subjected to solid phase polymerization at 240 ° C. and 0.4 torr for 3 hours to obtain a polyamide resin (nylon 6T / 66, ηr = 2.68). Got. The amino end group concentration was 4.8 × 10 ⁻⁵ mol / g. Using a TEX30 type twin screw extruder manufactured by Nippon Steel Works with a cylinder set temperature of 310 ° C. and a screw speed of 200 rpm, this polyamide resin and a stabilizer having a hydroxyl group were dry blended in the proportions shown in Table 2. Thereafter, the filler is supplied from the main feeder of the extruder, and the filler is supplied at a ratio shown in Table 2 from the side feeder installed at a position of about 0.35 when viewed from the upstream side when the total length of the screw is 1.0. Then, melt kneading was performed. The gut discharged from the die was immediately cooled in a water bath and pelletized with a strand cutter. The obtained pellets were dried under reduced pressure at 80 ° C. for 12 hours, and test pieces were prepared by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, cylinder temperature 305 ° C., mold temperature 120 ° C.). The specimens before and after the heat aging resistance test were subjected to a tensile test using a tensile tester, and the tensile strength retention rate was calculated. In addition, the degree of improvement in tensile strength retention due to the addition of a stabilizer having a hydroxyl group was calculated as “strength retention after addition−non-addition strength retention” and represents a non-addition strength retention. Together with. The results are as shown in Table 2.

(Examples 11 and 12, Comparative Examples 21 and 22)
Using a TEX30 type twin screw extruder manufactured by Nippon Steel Works, set at a cylinder setting temperature of 270 ° C. and a screw speed of 200 rpm, polypentamethylene adipamide obtained in Reference Example 4, a hydroxyl group stabilizer and impact resistance The improver was dry blended at the ratio shown in Table 3, and then supplied from the main feeder of the extruder and melt kneaded. The gut discharged from the die was immediately cooled in a water bath and pelletized with a strand cutter. The obtained pellets were dried under reduced pressure at 80 ° C. for 12 hours, and test pieces were prepared by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, cylinder temperature 265 ° C., mold temperature 80 ° C.). The specimens before and after the heat aging resistance test were subjected to a tensile test using a tensile tester, and the tensile strength retention rate was calculated. In addition, the degree of improvement in tensile strength retention due to the addition of a stabilizer having a hydroxyl group was calculated as “strength retention after addition−non-addition strength retention” and represents a non-addition strength retention. Together with. The results are as shown in Table 3.

(Comparative Examples 23-25)
Using a TEX30 twin screw extruder manufactured by Nippon Steel Works with a cylinder set temperature of 280 ° C. and a screw speed of 200 rpm, the sulfuric acid relative viscosity was 2.78 and the amino end group concentration was 3.1 × 10 ⁻⁵ mol / After dry blending the nylon 66 resin (E3001 manufactured by Toray Industries, Inc.), a hydroxyl group-containing stabilizer, and an impact resistance improver in the proportions shown in Table 3, they were supplied from an extruder main feeder and melt-kneaded. The gut discharged from the die was immediately cooled in a water bath and pelletized with a strand cutter. The obtained pellets were dried under reduced pressure at 80 ° C. for 12 hours, and test pieces were prepared by injection molding (SG75H-MIV manufactured by Sumitomo Heavy Industries, cylinder temperature 275 ° C., mold temperature 80 ° C.). The specimens before and after the heat aging resistance test were subjected to a tensile test using a tensile tester, and the tensile strength retention rate was calculated. In addition, the degree of improvement in tensile strength retention due to the addition of a stabilizer having a hydroxyl group was calculated as “strength retention after addition−non-addition strength retention” and represents a non-addition strength retention. Together with. The results are as shown in Table 3.

(B) Stabilizer having a hydroxyl group, stabilizer having no hydroxyl group, monocarboxylic acid and acid anhydride used in Examples and Comparative Examples are as follows.
(B-1): N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide) (IRGANOX 1098, abbreviation TTAD, manufactured by Ciba Specialty Chemicals)
(B-2): Trimethylolethane (manufactured by Sigma-Aldrich)
(B-3): Dipentaerythritol (Tokyo Kasei)
(B-4): Diglycerin (Diglycerin S manufactured by Sakamoto Pharmaceutical Co., Ltd.)
(B-5): Copper iodide (CuI) (97% grade 1 manufactured by Sigma-Aldrich Japan)
(B-6): Benzoic acid (Kanto Chemical, special grade)
(B-7): Phthalic anhydride (Kanto Chemical, Deer Special)
Similarly, the filler (c) is as follows.
(C-1): Glass fiber (T-289 manufactured by Nippon Electric Glass)
Similarly, (d) the impact resistance improver is as follows.
(D-1): Ethylene / butene-1-g-maleic anhydride copolymer (“MH5020” manufactured by Mitsui DuPont Polychemical)
From Comparative Examples 1, 2, Comparative Examples 7, 9, 10, Comparative Examples 18, 20 and Comparative Examples 21, 24, the polyamide resin containing tetramethylene diamine and / or pentamethylene diamine as a main constituent component is hexamethylene diamine. It can be seen that the tensile strength retention is lower than that of the polyamide resin as the main component, and the heat aging resistance is inferior.

  Examples 1, 2 and Comparative Examples 3 and 6, Examples 3, 4, 5 and Comparative Examples 11 and 15, Example 10 and Comparative Example 19, Examples 11 and 12, and Comparative Examples 23 and 25 have a hydroxyl group. By adding a stabilizer, the polyamide resin containing tetramethylene diamine and pentamethylene diamine as the main constituent has a greater degree of improvement in tensile strength retention than the polyamide resin containing hexamethylene diamine as the main constituent, and heat aging resistance It was found that the improvement effect of was great. It was possible to improve the tensile strength retention rate equivalent to that of the polyamide resin containing hexamethylenediamine as a main constituent.

  From Examples 3 and 5 and Comparative Example 8, the effect of improving the heat aging resistance is greater when the stabilizer having a hydroxyl group is added than when the stabilizer having no hydroxyl group is added. Was found to be large.

  From Examples 7 and 8, it was found that the heat aging resistance could be improved also by the addition of monocarboxylic acid and acid anhydride.

  From Example 9, it was found that even when a monocarboxylic acid was added during polycondensation, there was an effect of improving heat aging resistance.

  From Comparative Examples 4, 5, and 22, when the addition amount of the stabilizer having a hydroxyl group is less than 0.05 parts by weight, the effect of improving the heat aging resistance is small, and tetramethylenediamine and pentamethylenediamine are used as main constituents. It was found that the polyamide resin to be used is inferior in tensile strength retention rate to the polyamide resin containing hexamethylenediamine as a main constituent.

  From Comparative Examples 12-14, when the addition amount of the stabilizer which has a hydroxyl group exceeds 5 weight part, it turned out that the initial strength before a heat-aging test property falls significantly.

From Example 3 and Example 6, it was found that when the amino terminal group concentration of the polyamide resin was 8.0 × 10 ⁻⁵ mol / g or less, the degree of improvement in tensile strength retention was further increased.

  The polyamide resin composition of the present invention can be molded by any method such as generally known injection molding, injection compression molding, compression molding, extrusion molding, blow molding, press molding, and spinning, and can be processed into various molded products. Can be used. As molded products, it can be used as injection molded products, extrusion molded products, blow molded products, various films such as uniaxially stretched and biaxially stretched, sheets, various fibers such as unstretched yarn, stretched yarn, and superstretched yarn. . In particular, in the present invention, it is possible to process various electric / electronic parts, automobile parts, etc. by taking advantage of the excellent heat aging resistance.

Claims (13)

(A) For 100 parts by weight of a polyamide resin composed of an aliphatic diamine composed of tetramethylene diamine and / or pentamethylene diamine and a monomer containing a dicarboxylic acid having 6 to 18 carbon atoms as main components, b) A polyamide resin composition comprising 0.05 to 5 parts by weight of at least one selected from the group consisting of a stabilizer having a hydroxyl group, a monocarboxylic acid, and an acid anhydride. 2. The polyamide resin composition according to claim 1, wherein the (a) polyamide resin has an amino terminal group concentration of 8.0 × 10 ⁻⁵ mol / g or less. The carbon number 6-18 dicarboxylic acid is at least one selected from adipic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, terephthalic acid, and isophthalic acid. 2. The polyamide resin composition according to 2. The polyamide resin composition according to any one of claims 1 to 3, wherein (b) the stabilizer having a hydroxyl group is at least one selected from the group consisting of a phenol-based stabilizer and a polyhydric alcohol compound. object. 5. The polyamide resin composition according to claim 4, wherein the polyhydric alcohol compound has a residue of pentaerythritol, glycerin, trimethylolethane and / or trimethylolpropane. The stabilizer (b) having a hydroxyl group is N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), triethylene glycol-bis (3- (3 -T-butyl-5-methyl-4-hydroxyphenyl) propionate), pentaerythrityltetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate, pentaerythritol, dipentaerythritol, tripentaerythritol, diglycerin, polyglycerin, trimethylolethane, and trimethylolpropane, The polyamide resin composition according to any one of claims 1 to 5 The polyamide resin composition according to claim 1, wherein the (b) monocarboxylic acid is benzoic acid. The polyamide resin composition according to any one of claims 1 to 3, wherein the acid anhydride (b) is at least one selected from the group consisting of succinic anhydride, maleic anhydride and phthalic anhydride. object. The polyamide resin composition according to any one of claims 1 to 8, wherein (a) 1 to 200 parts by weight of a filler is further blended with 100 parts by weight of the polyamide resin. The polyamide resin composition according to any one of claims 1 to 8, wherein (d) 5 to 100 parts by weight of an impact resistance improver is further blended with 100 parts by weight of the polyamide resin. A molded article formed by injection molding the polyamide resin composition according to claim 1. The polyamide resin composition according to any one of claims 1 to 10, wherein at least one of the (a) polyamide resin and (b) a stabilizer having a hydroxyl group, a monocarboxylic acid, and an acid anhydride are melt-kneaded. Manufacturing method. The polyamide resin composition according to any one of claims 1 to 10, wherein at least (a) a monomer constituting the polyamide resin and (b) a stabilizer having a hydroxyl group and / or a monocarboxylic acid are added and polycondensed. Production method.