JP2510414B2 - Polyamide composition and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyamide composition and a method for producing the same,
Specifically, in particular, it is a polyamide composition which is excellent not only in heat aging resistance but also in heat resistance, mechanical properties and chemical / physical properties, and also in moldability, that is, fluidity. And a manufacturing method thereof.

(Prior Art) In general, thermoplastic resins such as polyolefins, polyesters, and polyamides have excellent moldability, so that melt molding such as compression molding, injection molding or extrusion molding can be easily performed, but heat resistance, Since the engineering plastics are still unsatisfactory in both mechanical properties and chemical properties, they are used in their respective general-purpose molding fields by taking advantage of their respective properties.

On the other hand, polytetrafluoroethylene known as Teflon (registered trademark) and polyparaphenylene terephthalate known as Kevlar (registered trademark) are engineering plastics that are superior in heat resistance, mechanical properties, and chemical-physical properties. Amide, a polyimide composed of a condensation product of 4,4'-diaminodiphenyl ether known as Kapton (registered trademark) and pyromellitic anhydride, polyhexamethylene adipamide known as 6,6-nylon, and trogamide T ( Poly (2,2,4-trimethylhexamethylene terephthalamide) known as a registered trademark, polyphenylene sulfide, polyacetal and the like are used for various applications.

However, among these, polytetrafluoroethylene, polyparaphenylene terephthalamide, and the above polyimide have excellent heat resistance, mechanical properties, and chemical-physical properties, but since they cannot be melt-molded, The field of use is extremely limited. On the other hand, polyphenylene sulfide, polyhexamethylene adipamide, 2,2,4-trimethylhexamethylene terephthalamide, polyacetal, etc., all have the advantage that they can be melt-molded, on the other hand, Polyphenylene sulfide is inferior in heat resistance properties such as melting point, glass transition point, heat deformation temperature, and mechanical properties such as impact strength and wear resistance.
On the other hand, polyamides such as polyhexamethylene adipamide and 2,2,4-trimethylhexamethylene terephthalamide all have heat resistance characteristics such as glass transition point and heat distortion temperature,
Poor mechanical properties such as tensile strength, bending strength, limiting PV value, wear resistance, etc. and chemical properties such as chemical resistance, boiling water resistance and saturated water absorption. Further, polyacetal is inferior in heat resistance characteristics such as melting point and heat deformation temperature and mechanical strength such as bending strength, impact strength and abrasion resistance.

In order to solve the problems in the conventional engineering plastics as described above, the present inventors have already consisted of an aromatic dicarboxylic acid component unit containing an terephthalic acid component unit as a main component and an aliphatic alkylenediamine component unit. It has been found that polyamide has excellent heat resistance, mechanical strength, chemical-physical characteristics, and molding characteristics, and particularly excellent sliding characteristics (Japanese Patent Application No. 59-1204).
No. 0). However, the present inventors have further conducted extensive studies on this polyamide in order to improve its heat aging resistance, and as a result, by adding a predetermined phosphoric acid ester or phosphite ester, excellent heat aging resistance is obtained. It was found that it is possible to obtain a polyamide composition as a molding material that gives a molded product having, in particular, to add a phosphoric acid ester or a phosphorous acid ester at any stage of polycondensing a polyamide raw material to produce a polyamide. Therefore, it is possible to obtain a polyamide composition having remarkably excellent fluidity and excellent moldability, and further, this polyamide composition was found to give a molded article having excellent heat aging resistance, The present invention has been achieved.

(Structure of the Invention) The polyamide composition according to the present invention has (A) (a) a terephthalic acid component unit in the range of 60 to 85 mol%, and contains 15 or more aromatic dicarboxylic acid component units other than the terephthalic acid component unit. To 40 mol% of aromatic dicarboxylic acid component units, and (b) a polyamide comprising a hexamethylenediamine component unit, and (B) 0.01 to 5 mol% with respect to the hexamethylenediamine component constituting the polyamide. It is characterized by containing the phosphoric acid ester or phosphorous acid ester of.

Further, the method for producing a polyamide composition according to the present invention is (a) wherein the terephthalic acid component unit is in the range of 60 to 85 mol% and the aromatic dicarboxylic acid component unit other than the terephthalic acid component unit is 15 to 40 mol%. % Of the aromatic dicarboxylic acid component unit in the range of (b) and (b) hexamethylenediamine component unit, (c) 0.01 to 5 mol relative to the hexamethylenediamine component constituting the polyamide. % Of the phosphoric acid ester or phosphorous acid ester, the aromatic dicarboxylic acid component and the hexamethylenediamine component are polycondensed, or their nylon salts or oligomers are polycondensed.

In the polyamide composition according to the present invention, the polyamide (A) comprises (a) a terephthalic acid component unit in the range of 60 to 85 mol% and an aromatic dicarboxylic acid component unit other than the terephthalic acid component unit of 15 to 40%. It comprises an aromatic dicarboxylic acid component unit in the range of mol% and (b) hexamethylenediamine component unit.

In the present invention, the aromatic dicarboxylic acid component unit (a)
Has a terephthalic acid component unit in the range of 60 to 85 mol%, and an aromatic dicarboxylic acid component unit other than the terephthalic acid component unit in the range of 15 to 40 mol%.

Specific examples of the aromatic dicarboxylic acid component unit other than the terephthalic acid component unit include component units such as isophthalic acid, phthalic acid, 2-methylterephthalic acid, and naphthalenedicarboxylic acid. Among these, an isophthalic acid component unit or a naphthalenedicarboxylic acid component unit, particularly an isophthalic acid component unit is preferably used.

In the present invention, in the aromatic dicarboxylic acid component unit (a), terephthalic acid is less than 60 mol%,
Further, when the aromatic dicarboxylic acid component unit other than the isophthalic acid component unit is more than 40 mol%, the molded product obtained from the composition containing such a polyamide has a heat resistance property including heat aging resistance and heat deformation temperature, and a tensile strength. , Inferior in mechanical properties such as flexural strength and abrasion resistance, and chemical and physical properties such as chemical resistance and water resistance.

However, in the present invention, the aromatic dicarboxylic acid component unit (a) is used in a small amount, for example, about 10 mol% of adipic acid together with the terephthalic acid component unit and the aromatic dicarboxylic acid component unit other than the terephthalic acid component unit. It does not matter that the polyvalent carboxylic acid component unit such as sebacic acid, trimellitic acid, and pyromellitic acid is contained.

In the polyamide composition according to the present invention, hexamethylenediamine is used as the diamine component unit (b).

According to the present invention, as the diamine component,
Along with hexamethylenediamine, the terephthalic acid component unit is in the range of 60 to 85 mol%, and the aromatic dicarboxylic acid component unit other than the terephthalic acid component unit is in the range of 15 to 40 mol%. By using a), the obtained polyamide composition has excellent moldability, and also has excellent heat resistance properties such as heat aging resistance and heat distortion temperature, and mechanical properties such as bending strength and abrasion resistance. give.

That is, when the terephthalic acid component unit exceeds 85 mol% in the aromatic dicarboxylic acid component unit, the obtained polyamide composition has a high melting point and is close to the decomposition point, which makes molding difficult.

Further, in the polyamide composition according to the present invention, the polyamide is soluble in concentrated sulfuric acid at a temperature of 50 ° C., and the intrinsic viscosity [η] measured in concentrated sulfuric acid at a temperature of 30 ° C. is 0.5 dl / It is preferably at least g. Preferably, [η] is 0.6 dl / g or more, particularly preferably 0.7 to 3.0 d.
It is in the l / g range.

Such concentrated sulfuric acid-soluble polyamide can be obtained by a method already known in the art. For example,
Polymer Reviews, 10 , Condensation Polymers by Inter
facial and Solution Methods (PWMorgan, Inters
cience Publishers (1965) and, Makromol.Chem., 47, 93
-113 (1961)), it is obtained by polycondensing a diacid halide of an aromatic dicarboxylic acid, which is the above-mentioned polyamide constituent unit, and hexamethylenediamine by a solution method. You can It can also be obtained by an interfacial polymerization method. Alternatively,
It can also be obtained by polycondensation of the aromatic dicarboxylic acid and hexamethylenediamine or a nylon salt thereof in the presence or absence of a solvent such as water by a melting method. Further, it can also be obtained by polycondensing the polyamide oligomer obtained by the former method by a solid phase polymerization method.

Furthermore, in the polyamide composition according to the present invention, the polyamide is not only the concentrated sulfuric acid-soluble polyamide,
Although it has a composition in the same range as this concentrated sulfuric acid-soluble polyamide, it may contain a polyamide insoluble in concentrated sulfuric acid at 50 ° C. Here, the polyamide insoluble in concentrated sulfuric acid at 50 ° C. is crushed polyamide, and a concentrated 1% by weight concentrated sulfuric acid solution of polyamide passing through 32 mesh is heated and stirred at 50 ° C. for 10 hours, and then the temperature is raised to 50 ° C. Refers to a polyamide from which the soluble portion has been removed by filtration with a 2G glass filter. Such concentrated sulfuric acid-insoluble polyamide is not particularly limited, but the melt viscosity (MFR) at 360 ° C and a load of 2.16 kg.
However, usually, 20g / 10 minutes or less, preferably 5g / 10 minutes or less,
Particularly preferably, it is 0.1 g / 10 minutes or less.

Such concentrated sulfuric acid-insoluble polyamide can be produced as a by-product during the production of the concentrated sulfuric acid-soluble polyamide.
In addition, the production amount can be intentionally increased by selecting the reaction conditions. Therefore, in such a case, a mixture of concentrated sulfuric acid-soluble polyamide and concentrated sulfuric acid-insoluble polyamide can be obtained. Further, if necessary, the concentrated sulfuric acid-soluble polyamide or the mixture of the concentrated sulfuric acid-soluble polyamide and the concentrated sulfuric acid-insoluble polyamide may be further crosslinked to have a high molecular weight so that the concentrated sulfuric acid is insoluble.

Therefore, without any limitation, as a method for producing a mixture of concentrated sulfuric acid-insoluble polyamide or concentrated sulfuric acid-soluble polyamide and concentrated sulfuric acid-insoluble polyamide, for example, a method of further solid-state polymerization of the concentrated sulfuric acid-soluble polyamide, When producing concentrated sulfuric acid-soluble polyamide by melt polycondensation, the polycondensation temperature is set higher, for example, about 34
0 ° C or higher, polycondensation of hexamethylenediamine and aromatic dicarboxylic acid with a charged molar ratio of 1.03 or higher, and hexamethylenediamine and aromatic dicarboxylic acid together with trifunctional or higher polyamine or polycarboxylic acid A method of using an acid in combination and polycondensing it can be exemplified.

In the polyamide composition according to the present invention, the concentrated sulfuric acid-insoluble polyamide is preferably contained in an amount of 1000 parts by weight or less based on 100 parts by weight of concentrated sulfuric acid-soluble polyamide. Particularly, according to the present invention, 100 parts by weight of concentrated sulfuric acid-soluble polyamide is mixed with 2 parts of concentrated sulfuric acid-insoluble polyamide.
When it is contained in an amount of from about 1000 parts by weight, preferably from 3 to 600 parts by weight, and particularly preferably from 5 to 400 parts by weight, a molded product obtained from such a polyamide composition has excellent mechanical strength such as bending strength.

Here, the ratio of the concentrated sulfuric acid-soluble polyamide and the concentrated sulfuric acid-insoluble polyamide in the polyamide is determined by the following method. That is, a 1% by weight concentrated sulfuric acid solution of a polyamide mixture crushed into 32 mesh passes was heated with stirring at a temperature of 50 ° C. for 10 hours, cooled to room temperature, and then filtered with a 2G glass filter to obtain a polyamide obtained as a precipitate. Then, the polyamide contained in the filtrate and the polyamide obtained by precipitating the polyamide contained in the filtrate are collected, dried, and the respective weights are measured.

The polyamide composition according to the present invention contains an organic phosphoric acid ester or an organic phosphorous acid ester. In the present invention, phosphoric acid triester or phosphorous acid triester is particularly preferable. Specific examples of the phosphoric acid triester, trimethyl phosphate, triethyl phosphate, triisopropyl phosphate, tributyl phosphate, trihexyl phosphate, triisodecyl phosphate, trioctadecyl phosphate,
Examples thereof include tridecyl phosphate, tristearyl phosphate, triphenyl phosphate and the like. Further, as specific examples of phosphite triester, trimethyl phosphite, triethyl phosphite, triisopropyl phosphite, tributyl phosphite, trihexyl phosphite, triisodecyl phosphite, trioctadecyl phosphite, phosphite. Examples thereof include tridecyl phosphate, tristearyl phosphite, and triphenyl phosphite.

These phosphoric acid esters or phosphorous acid esters, in the polyamide composition according to the present invention, 0.01 ~ 0.01 to the hexamethylene diamine component constituting the polyamide.
It is incorporated in the range of 5 mol%, preferably in the range of 0.02 to 2 mol%, particularly preferably in the range of 0.05 to 1 mol%. When the amount of the phosphoric acid ester or phosphorous acid ester is less than 0.01 mol% with respect to the hexamethylenediamine component, the improvement in heat aging resistance of the molded product obtained from such a polyamide composition is still insufficient, while When it is compounded in a large amount in excess of 5 mol%, mechanical strength such as tensile strength and bending strength will decrease. In particular, as will be described later, the amount of phosphoric acid ester or phosphorous acid ester is 5 mol%
When a large amount is exceeded, when a polyamide composition is produced by polycondensing a polyamide raw material in the presence of a phosphoric acid ester or a phosphorous acid ester, the molecular weight of the obtained polyamide does not become sufficiently large. The strength and bending strength will decrease.

As described above, the polyamide can be obtained by any method such as a melting method, a solid-phase method, and a combination thereof, but the polyamide composition according to the present invention can be manufactured by these methods. It can be obtained by adding the phosphoric acid ester or phosphorous acid ester at any stage. It can also be obtained by adding and mixing a phosphoric acid ester or a phosphorous acid ester to the polyamide obtained by any method.

However, in the present invention, by adding the phosphoric acid ester or phosphorous acid ester at the stage of polycondensing the dicarboxylic acid component and the hexamethylenediamine component, or a nylon salt or an oligomer thereof, particularly fluidity is obtained. It is possible to obtain a polyamide composition having excellent properties, and further, such a polyamide composition gives a molded product having particularly excellent heat aging resistance.

In the polyamide composition according to the present invention, other than a phosphoric acid ester or a phosphorous acid ester, if necessary, a conventionally known polymer, a stabilizer, a plasticizer, a release agent,
It may contain a lubricant, a filler and the like. Examples of the polymer include polyamides such as nylon 66 and nylon 6 and the like.

As the filler, conventionally known organic or inorganic substances having various forms such as powder, plate, fiber or cloth can be used.

As the inorganic filler, for example, silica, alumina,
Silica-alumina, talc, diatomaceous earth, clay, kaolin, quartz, glass, mica, graphite, molybdenum disulfide, gypsum, red iron oxide, titanium dioxide, zinc oxide, aluminum, copper, stainless powder, etc. ,
Glass fiber, carbon fiber, boron fiber, ceramic fiber,
Examples thereof include fibrous materials such as asbestos fibers and stainless steel fibers, or cloth-shaped materials as secondary processed products thereof.

Examples of the organic filler include polyparaphenylene terephthalamide, polymetaphenylene terephthalamide, polyparaphenylene isophthalamide, polymetaphenylene isophthalamide, diaminodiphenyl ether and terephthalic acid and / or isophthalic acid. Wholly aromatic polyamide such as condensate with acid, condensate of para- or meta-aminobenzoic acid, wholly aromatic polyamideimide such as condensate of diaminodiphenyl ether and trimellitic anhydride and / or pyromellitic acid, wholly aromatic Group polyimide,
Examples include polybenzimidazole, a heterocycle-containing polymer such as polyimidazophenanthroline, a powdered material such as polytetrafluoroethylene, a plate-shaped material, a fibrous material or a cloth-shaped material as a secondary processed product thereof. it can.

The above-mentioned fillers are blended alone or as a mixture, and if necessary, these fillers may be treated with a silane coupling agent, a titanium coupling agent or the like.

Among the above-mentioned fillers, as a powdery material, silica,
Silica-alumina, alumina, titanium dioxide, graphite, molybdenum disulfide, polytetrafluoroethylene and the like are preferably used, but in particular, graphite, molybdenum disulfide and polytetrafluoroethylene are used for dynamic friction of molded articles obtained from the composition. Coefficient, Taber wear, limit
It is preferably used because it improves abrasion resistance such as PV value. Such a filler is preferable when the average particle diameter is usually in the range of 0.1 mμ to 200 μ, particularly in the range of 1 mμ to 100 μ, because the abrasion resistance of the obtained molded product is remarkably improved.

The amount of the powdery filler as described above is 200 parts by weight or less, preferably 100 parts by weight with respect to 100 parts by weight of the polyamide composition.
In the range of 0.5 parts by weight or less, particularly preferably 0.5 to 50 parts by weight.

Further, when the fiber made of the wholly aromatic polyamide is used as the filler, the mechanical properties such as tensile strength and Izod impact strength of the molded product obtained from the composition, and the heat resistance properties such as heat distortion temperature are further improved. When glass fiber, carbon fiber or boron fiber is used as the fibrous inorganic filler, mechanical properties such as tensile strength, bending strength and bending elastic modulus of the molded product obtained from the composition, heat deformation temperature, etc. The heat resistance and chemical / physical properties such as water resistance are further improved.

These fibrous fillers are usually 0.1 to 20 mm, especially 1
It is preferred to have an average length in the range of ~ 10 mm. The blending amount is usually 200 parts by weight or less, preferably 5 to 180 parts by weight, and particularly preferably 5 to 150 parts by weight with respect to 100 parts by weight of polyamide.

The polyamide composition according to the present invention is a usual melt molding,
For example, it can be molded by compression molding, injection molding or extrusion molding.

(Effect of the invention) As described above, the polyamide composition of the present invention contains a polyamide having a predetermined composition and a phosphoric acid ester or a phosphorous acid ester, and is a molded product obtained from such a polyamide composition. In particular, its heat aging resistance is remarkably improved. Of course, heat resistance characteristics such as melting point, glass transition point and heat distortion temperature, tensile strength, bending strength, impact characteristics,
Dynamic friction coefficient, mechanical properties such as Taber abrasion, chemical resistance,
It is also excellent in chemical and physical properties such as boiling water resistance and saturated water absorption, flowability of melt composition, melt compression moldability, melt injection moldability and melt extrusion moldability.

In particular, when producing a polyamide having a high molecular weight with the component unit composition specified in the present invention, for example, by melt polymerization or solid phase polymerization, high temperature conditions are required. By polycondensing a polyamide raw material in the presence of an acid ester or a phosphorous acid ester, thermal deterioration of the polymer is prevented even during polycondensation, and further,
A polyamide composition having excellent fluidity can be obtained. Further, this composition gives a molded article having excellent heat aging resistance.

(Examples) Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.
In the table below, the abbreviations represent the following compounds, respectively.

TA: terephthalic acid IA: isophthalic acid C ₆ DA: 1,6-hexamethylenediamine The method for preparing test pieces and the evaluation method for each performance are as follows.

(Preparation of Test Pieces of Molded Polyamide Composition and Evaluation of Physical Properties) The polyamide composition was crushed by a crusher (passed through 32 mesh) and dried at 100 ° C. and 1 mmHg for 12 hours.
This polyamide composition was pressed by a press molding machine in a nitrogen atmosphere under a pressure of 100 kg / cm ^{2 to} a temperature of 20 or higher than the melting point of polyamide.
After hot-pressing at a temperature higher by ° C, it was cold-pressed at a temperature of 20 ° C to prepare a compression molded plate having a thickness of 2 to 4 mm. These molded plates were cut into test pieces of the dimensions shown in Table 1 and then placed in an atmosphere at a temperature of 23 ° C and a relative humidity of 65% for 96 hours.
After leaving it for an hour, it was subjected to each test. The heat aging resistance was evaluated by the bending strength after the bending test piece was stored in an air oven at 250 ° C. for 2 days, and its storage ratio to the initial value.

In addition, the glass fiber-containing molded product was 60 parts by weight of crushed and dried polyamide and 40 parts by weight of glass fiber (average length 6 mm, manufactured by Nitto Boseki Co., Ltd. CS 6PE-231) and a predetermined stability. Single-screw extruder (L / D = 28, 20mm
Diameter) and mixed to obtain a polyamide composition in the form of a strand having a size of about 6 mm. Using this, press molding was carried out in the same manner as in the case where the above glass fiber was not blended to prepare a test piece.

Example 1 123.6 g (0.744 mol) terephthalic acid, 52. isophthalic acid.
9g (0.318 mol) hexamethylenediamine 123.4g (1.06
Mol), 0.666 g (1.06 mmol) of tridecyl phosphite, and 33 g of ion-exchanged water were charged into a 1-volume autoclave, and after sufficiently purging with nitrogen, the temperature was raised to 280 ° C. under stirring for 2 hours. . Further, the reaction was allowed to proceed at 280 ° C. for 1 hour in the sealed state, the stirring was stopped, and the reaction mixture was taken out from the bottom of the autoclave at a differential pressure of 10 kg / cm ² . This was dried in nitrogen at 100 ° C. and 100 mmHg overnight.

This oligomer is a twin-screw extruder (Screen diameter 30 mm, L /
D = 42, barrel temperature (℃) 30/260/280/300/300/320/320 /
340/340/340, 4th and 6th zones are vented to the atmosphere, rotation speed is 80 rpm, oligomer feed rate is 2 kg / hr, exhaust is nitrogen purge) to proceed polycondensation to obtain high molecular weight polyamide composition. It was Table 2 shows the properties of the polyamide composition thus obtained and the physical properties of molded test pieces obtained from this composition.

Example 2 Example 3 was repeated except that 0.33 g (1.06 mmol) of triphenyl phosphite was used as the phosphite.
A polyamide composition was produced in the same manner as in Example 1. Table 2 shows the properties of the polyamide composition thus obtained and the physical properties of molded test pieces obtained from this composition.

(Production of concentrated sulfuric acid-insoluble polyamide) Example 3 The polyamide composition obtained in Example 1 was treated at 280 ° C and 1 mm.
Solid-state polymerization was carried out for 4 hours under stirring under Hg conditions to increase the molecular weight to obtain a concentrated sulfuric acid-insoluble polyamide composition. Table 2 shows the properties of the polyamide thus obtained and the physical properties of the molded test piece obtained from this composition.

Example 4 In Example 1, 129.6 g of hexamethylenediamine
(1.12 mol) and the oligomer was obtained in the same manner as in Example 3 except that 0.346 g (1.06 mmol) of triphenyl phosphate was used instead of tridecyl phosphite. To obtain a concentrated sulfuric acid-insoluble polyamide composition. Table 2 shows the properties of the polyamide thus obtained and the physical properties of the molded test piece obtained from this composition.

Example 5 In Example 1, 114.7 g (0.70 mol) of terephthalic acid
And using 61.7 g (0.37 mol) of isophthalic acid,
An oligomer was obtained in the same manner as in Example 1, which was used in Example 3.
Higher molecular weight was obtained in the same manner as above to obtain a concentrated sulfuric acid insoluble polyamide composition. Table 2 shows the properties of the polyamide thus obtained and the physical properties of the molded test piece obtained from this composition.

Example 6 A composition was prepared by mixing 60 parts by weight of polyamide synthesized by the method of Example 1 with 40 parts by weight of glass fiber (average length 6 mm, manufactured by Nitto Boseki Co., Ltd. CS 6PE-231). This physical property was evaluated. The results are shown in Table 2.

Comparative Examples 1 and 2 Polyamide was synthesized according to the method of Example 1 except that tridecyl phosphite was used in the amount described in Table 2 in Example 1. The results are shown in Table 2.

Comparative Example 3 Terephthalic acid 158.0 g (0.952 mol), isophthalic acid 17.
6g (0.106 mol), hexamethylenediamine 123.4g (1.0
6 mol), tridecyl phosphite 0.666 g (1.06 mmol)
Then, 33 g of ion-exchanged water was charged into a 1-volume autoclave, and after sufficiently purging with nitrogen, the temperature was raised to 280 ° C. under stirring for 2 hours. Further, the reaction was allowed to proceed at 280 ° C. for 1 hour in the sealed state, the stirring was stopped, and the reaction mixture was taken out from the bottom of the autoclave at a differential pressure of 10 kg / cm ² . This was dried in nitrogen at 100 ° C. and 100 mmHg overnight to obtain an oligomer.

The [η] of this oligomer measured in concentrated sulfuric acid at 30 ° C is
It was 0.15 dl / g.

This oligomer is a twin-screw extruder (Screen diameter 30 mm, L /
D = 42, barrel temperature (℃) 30/260/290/320/350/350/350 /
In the 350/350/350, 4th and 6th zones, the polycondensation was promoted by an air vent, an engine speed of 80 rpm, an oligomer supply rate of 2 kg / hour, and an exhaust gas of nitrogen purge) to increase the molecular weight.

The obtained polyamide had a [η] of 1.20 dl / g and a melting point of 355 ° C. measured in concentrated sulfuric acid at 30 ° C.

 This polyamide foam-decomposed during molding.

Comparative Example 4 In Comparative Example 3, terephthalic acid 97.0 g (0.58 mol)
And using isophthalic acid 79.4 g (0.48 mol),
A polyamide was produced in the same manner as in Comparative Example 3.

40 parts by weight of glass fiber (average length 6 mm, manufactured by Nitto Boseki Co., Ltd., Chopped Strand C)
S 6PE-231) blended composition was prepared and its physical properties were evaluated. The results are shown in Table 2.

Claims (2)

(57) [Claims] 1. A terephthalic acid component unit of (A) (a) is 60 to
Aromatic dicarboxylic acid component units in the range of 85 mol% and aromatic dicarboxylic acid component units other than terephthalic acid component units in the range of 15 to 40 mol%, and (b) hexamethylenediamine component unit. A polyamide composition, and (B) a polyamide composition comprising 0.01 to 5 mol% of a phosphoric acid ester or a phosphorous acid ester based on the hexamethylenediamine component constituting the polyamide. 2. An aromatic dicarboxylic acid wherein (a) the terephthalic acid component unit is in the range of 60 to 85 mol%, and the aromatic dicarboxylic acid component unit other than the terephthalic acid component unit is in the range of 15 to 40 mol%. When producing a polyamide comprising an acid component unit and (b) a hexamethylenediamine component unit, (c) 0.01 to 5 mol% of a phosphoric acid ester or phosphorus based on the hexamethylenediamine component constituting the polyamide. A method for producing a polyamide composition, which comprises polycondensing the aromatic dicarboxylic acid component and the hexamethylenediamine component in the presence of an acid ester, or polycondensing a nylon salt or oligomer thereof.