JP2014218550A - Polyamide resin composition - Google Patents

Abstract

[PROBLEMS] There is little increase in the back pressure of a filter at the time of molding, good thermal stability at the time of drying or molding, and there are few occurrences of abnormal appearance of foreign matter molded bodies such as gels and deterioration of transparency, To provide a polyamide resin composition excellent in productivity at the time of molding and a molded body using the same. A diamine unit containing 70 mol% or more of a specific formula xylylenediamine unit and a dicarboxylic acid containing 50 mol% or more of a linear aliphatic dicarboxylic acid unit of a specific formula and / or an aromatic dicarboxylic acid unit of a specific formula A polyamide resin composition obtained by adding a phosphorus compound represented by the following general formula (III) to a polyamide containing units. The polyamide resin composition whose molecular weight distribution (Mw / Mn) of the said polyamide is 1.6-4.0, and the addition amount of the said phosphorus compound (X) is 50-2000 ppm with respect to polyamide. [Selection figure] None

Description

  The present invention relates to a polyamide resin composition excellent in molding stability, and a molded body formed using the resin composition.

  Polyamides are widely used in applications such as hollow molded containers, films, sheet packaging materials, engineering plastics and fibers because of their excellent physical and mechanical properties. Typical examples of the polyamide include aliphatic polyamides such as nylon 6 and nylon 66. As polyamides other than aliphatic polyamides, polyamides derived from aromatic diamines such as paraxylylenediamine (PXDA) and metaxylylenediamine (MXDA) as diamine structural units, and aromatics such as terephthalic acid as dicarboxylic acid structural units Polyamides derived from dicarboxylic acids are known. These so-called semi-aromatic polyamides exhibit excellent physical properties such as low water absorption and high elastic modulus in addition to the excellent physical properties of aliphatic polyamides.

  However, polyamide is generally more unstable to heat than polyester and the like, and gelation, yellowing, etc. are caused by thermal degradation in a system without oxygen or thermal oxidation degradation in a system with oxygen. It may happen. As a method for suppressing thermal deterioration of a polyamide-free system, a method of adding a phosphonic acid compound or a phosphorous acid compound and an alkali metal to the polyamide has been proposed (for example, see Patent Document 1).

  Further, as a method for suppressing thermal degradation of polyamide, (a) phosphinic acid compound, phosphonous acid compound, phosphonic acid compound or phosphorous acid compound, (b) alkali metal, (c) phenylenediamine and / or Or the method of mix | blending with the derivative (s) is proposed (for example, refer patent document 2).

As a method of preventing thermal deterioration in a system below the melting point of polyamide and in the absence of oxygen, pyrophosphite, amide compound of organic phosphinic acid, barium salt of mono or diester of phosphorous acid, orthophosphoric acid A method of adding a copper salt of a mono- or diester has been proposed (for example, see Patent Document 3).
Patent Document 4 discloses at least one kind selected from a lubricant, an organophosphorus stabilizer, a hindered phenol compound, and a hindered amine compound as a measure for preventing the formation of a gelled polyamide comprising metaxylylenediamine and adipic acid. The method of adding 0.0005 to 0.5 weight part of the above is proposed (for example, refer patent document 4).

  Patent Document 5 discloses a method for obtaining a polyamide having an excellent color tone while improving the degree of polymerization of the polyamide by polymerizing a polyamide comprising terephthalic acid and hexamethylenediamine in the presence of hypophosphite. Has been. Patent Document 6 discloses a method of polymerizing adipic acid, terephthalic acid, isophthalic acid and hexamethylenediamine in the presence of hypophosphite.

JP 49-45960 A JP-A-49-53945 Japanese Patent Publication No.46-38351 JP 2001-164109 A JP-A-5-43681 Japanese Patent Laid-Open No. 3-126725

  However, although these techniques are effective in preventing the gelation of polyamide, they are not satisfactory, and in particular, the reduction of clogging which affects the increase in filter back pressure during molding has not been solved. Furthermore, depending on the molding conditions such as drying conditions, molding temperature, and melting time, coloring and gelation and the generation of foreign matters resulting from this, abnormal appearance of the molded product, or deterioration of transparency may occur, and a solution is desired. Yes.

Therefore, the present invention relates to a polyamide resin composition having excellent molding stability by suppressing an increase in filter back pressure during molding, and generation of foreign matter such as foreign matter and gel-like matter due to thermal decomposition, and a molded body comprising the polyamide resin composition. It is an issue to provide.

  The inventors of the present invention have arrived at the present invention as a result of intensive studies to achieve the above object. That is, a diamine unit containing 70 mol% or more of an aromatic diamine unit represented by the following general formula (I), a linear aliphatic dicarboxylic acid unit represented by the following general formula (II-1) and / or the following general A polyamide resin obtained by adding a phosphorus compound (X) represented by the following general formula (III) to a polyamide containing a dicarboxylic acid unit containing 50 mol% or more of an aromatic dicarboxylic acid unit represented by the formula (II-2) Composition.

［前記一般式（ＩＩ−１）中、ｎは２〜１８の整数を表す。前記一般式（Ｉ
Ｉ−２）中、Ａｒはアリーレン基を表す。

[In said general formula (II-1), n represents the integer of 2-18. The general formula (I
In I-2), Ar represents an arylene group.

  The polyamide resin composition of the present invention improves the polymerization rate by adding a specific phosphorus compound (X) to the polyamide and shortens the polymerization time. Therefore, productivity is excellent. In addition, because it has good thermal stability and thermal oxidation stability during drying and molding, it has excellent color tone, is difficult to be colored in the molding process, and generates less foreign matter such as gels. And is suitably used as a raw material for molded articles such as films and sheets, hollow molded containers including beverage bottles, and engineering plastics materials.

<Polyamide resin composition>
The polyamide resin composition of the present invention contains polyamide and a phosphorus compound (X).

<Polyamide>
The polyamide constituting the polyamide resin composition of the present invention is represented by a diamine unit containing 70 mol% or more of an aromatic diamine unit represented by the following general formula (I-1) and the following general formula (II-1). And / or a dicarboxylic acid unit containing 50 mol% or more of a linear aliphatic dicarboxylic acid unit represented by the following general formula (II-2).

［前記一般式（ＩＩ−１）中、ｎは２〜１８の整数を表す。前記一般式（ＩＩ−２）中、Ａｒはアリーレン基を表す。

[In said general formula (II-1), n represents the integer of 2-18. In the general formula (II-2), Ar represents an arylene group.

In the polyamide of the present invention, the content of the diamine unit is 25 to 50 mol%, and preferably 30 to 50 mol% from the viewpoint of polymer properties. Similarly, in the polyamide of the present invention, the content of the dicarboxylic acid unit is 25 to 50 mol%, preferably 30 to 50 mol%.
The proportion of the content of the diamine unit and the dicarboxylic acid unit is preferably substantially the same from the viewpoint of the polymerization reaction, and the content of the dicarboxylic acid unit is ± 2 mol% of the content of the diamine unit. More preferred. If the content of the dicarboxylic acid unit exceeds the range of ± 2 mol% of the content of the diamine unit, the degree of polymerization of the polyamide becomes difficult to increase, so it takes a lot of time to increase the degree of polymerization, and thermal degradation tends to occur. Become.

[Diamine unit]
The diamine unit in the polyamide of the present invention is represented by the general formula (I) from the viewpoint of improving transparency and color tone and facilitating moldability in addition to imparting excellent gas barrier properties to the polyamide. An aromatic diamine unit is contained in the diamine unit in an amount of 50 mol% or more, and the content is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and preferably 100 mol%. It is less than mol%.

  Examples of the compound that can constitute the aromatic diamine unit represented by the general formula (I) include orthoxylylenediamine, metaxylylenediamine, and paraxylylenediamine. These can be used alone or in combination of two or more.

  Examples of the compound that can constitute a diamine unit other than the aromatic diamine unit represented by the formula (I) include aromatic diamines such as paraphenylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis. (Aminomethyl) cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminomethyl) decalin, bis (Aminomethyl) tricyclodecane alicyclic diamines; tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2, 4-trimethyl Hexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, can be exemplified aliphatic diamines such as 2-methyl-1,5-pentanediamine, but is not limited thereto. These can be used alone or in combination of two or more.

[Dicarboxylic acid unit]
The dicarboxylic acid unit in the polyamide of the present invention is a linear aliphatic dicarboxylic acid unit represented by the general formula (II-1) and / or from the viewpoints of reactivity during polymerization, and crystallinity and moldability of the polyamide. Or the aromatic dicarboxylic acid unit represented by the general formula (II-2) is contained in the dicarboxylic acid unit in a total of 50 mol% or more, and the content is preferably 70 mol% or more, more preferably 80 mol%. % Or more, more preferably 90 mol% or more, and preferably 100 mol% or less.
[Linear aliphatic dicarboxylic acid unit]
The polyamide of the present invention is represented by the general formula (II-1) for the purpose of imparting flexibility necessary for a packaging material or packaging container in addition to imparting an appropriate glass transition temperature and crystallinity to the polyamide. It is preferable to contain a linear aliphatic dicarboxylic acid unit.
In said general formula (II-1), n represents the integer of 2-18, Preferably it is 3-16, More preferably, it is 4-12, More preferably, it is 4-8.
Examples of the compound that can constitute the linear aliphatic dicarboxylic acid unit represented by the general formula (II-1) include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1, Examples thereof include, but are not limited to, 10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, and the like. These can be used alone or in combination of two or more.

  The kind of the linear aliphatic dicarboxylic acid unit represented by the general formula (II-1) is appropriately determined according to the use. The linear aliphatic dicarboxylic acid unit in the polyamide of the present invention provides an excellent gas barrier property to the polyamide, and from the viewpoint of molding processability, an adipic acid unit, a sebacic acid unit, and 1,12-dodecanedicarboxylic acid. It is preferable that at least one selected from the group consisting of acid units is contained in a total of 50 mol% or more in the linear aliphatic dicarboxylic acid unit, and the content is more preferably 70 mol% or more, and still more preferably 80 mol%. The mol% or more, particularly preferably 90 mol% or more, and preferably 100 mol% or less.

  The linear aliphatic dicarboxylic acid unit of the polyamide of the present invention has 50 adipic acid units in the linear aliphatic dicarboxylic acid unit from the viewpoint of the gas barrier properties of the polyamide and the thermal properties such as an appropriate glass transition temperature and melting point. It is preferable to contain more than mol%. Further, the linear aliphatic dicarboxylic acid unit in the polyamide of the present invention is 50% by mole of sebacic acid unit in the linear aliphatic dicarboxylic acid unit from the viewpoint of imparting appropriate gas barrier properties and moldability to the polyamide. When the polyamide is used for applications requiring low water absorption, weather resistance, and heat resistance, the 1,12-dodecanedicarboxylic acid unit is 50 mol% or more in the linear aliphatic dicarboxylic acid unit. It is preferable to include.

[Aromatic dicarboxylic acid unit]
The polyamide of the present invention is an aromatic represented by the general formula (II-2) for the purpose of facilitating the molding processability of packaging materials and packaging containers in addition to imparting further gas barrier properties to the polyamide. It preferably contains a dicarboxylic acid unit.
In the general formula (II-2), Ar represents an arylene group. The arylene group is preferably an arylene group having 6 to 30 carbon atoms, more preferably 6 to 15 carbon atoms, and examples thereof include a phenylene group and a naphthylene group.
Examples of the compound that can constitute the aromatic dicarboxylic acid unit represented by the general formula (II-2) include terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, but are not limited thereto. is not. These can be used alone or in combination of two or more.

  The kind of the aromatic dicarboxylic acid unit represented by the general formula (II-2) is appropriately determined according to the use. The aromatic dicarboxylic acid unit in the polyamide of the present invention is a total of at least one selected from the group consisting of an isophthalic acid unit, a terephthalic acid unit, and a 2,6-naphthalenedicarboxylic acid unit in the aromatic dicarboxylic acid unit. The content is preferably 50 mol% or more, and the content is more preferably 70 mol% or more, further preferably 80 mol% or more, particularly preferably 90 mol% or more, and preferably 100 mol% or less. . Among these, it is preferable to contain isophthalic acid and / or terephthalic acid in the aromatic dicarboxylic acid unit. The content ratio of the isophthalic acid unit to the terephthalic acid unit (isophthalic acid unit / terephthalic acid unit) is not particularly limited and is appropriately determined according to the application. For example, from the viewpoint of reducing the appropriate glass transition temperature and crystallinity, the total of both units is preferably 100/100 to 100/0, more preferably 0/100 to 60/40, and even more preferably 0. / 100 to 40/60, more preferably 0/100 to 30/70.

  In the dicarboxylic acid unit of the polyamide of the present invention, the content ratio of the linear aliphatic dicarboxylic acid unit to the aromatic dicarboxylic acid unit (linear aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit) is not particularly limited. It is determined appropriately depending on the application. For example, when the purpose is to increase the glass transition temperature of the polyamide to lower the crystallinity of the polyamide, the linear aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit is preferably when the total of both units is 100. Is 0 / 100-60 / 40, more preferably 0 / 100-40 / 60, still more preferably 0 / 100-30 / 70. Further, when the purpose is to lower the glass transition temperature of the polyamide to impart flexibility to the polyamide, the linear aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit is preferably when the total of both units is 100 It is 40 / 60-100 / 0, More preferably, it is 60 / 40-100 / 0, More preferably, it is 70 / 30-100 / 0.

  Examples of the compound that can constitute a dicarboxylic acid unit other than the dicarboxylic acid unit represented by the general formula (II-1) or (II-2) include oxalic acid, malonic acid, fumaric acid, maleic acid, 1,3- Examples of the dicarboxylic acid include benzenediacetic acid and 1,4-benzenediacetic acid, but are not limited thereto.

[Tertiary hydrogen-containing carboxylic acid unit]
When the oxygen absorption function is imparted to the polyamide resin composition of the present invention, the following tertiary hydrogen-containing carboxylic acid units may be copolymerized with the polyamide. The tertiary hydrogen-containing carboxylic acid unit has at least one amino group and one carboxyl group, or two or more carboxyl groups from the viewpoint of polymerization of polyamide. Specific examples include structural units represented by the following general formula (IV).

[In the general formula (IV), R represents an alkyl group having 1 to 6 carbon atoms and an aryl group having 6 to 10 carbon atoms. ]

  Specific examples of preferable R in the general formula (IV) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, 1-methylpropyl group, 2-methylpropyl group. Group, hydroxymethyl group, 1-hydroxyethyl group, mercaptomethyl group, methylsulfanylethyl group, phenyl group, naphthyl group, benzyl group, 4-hydroxybenzyl group and the like can be exemplified, but not limited thereto. Among these, a methyl group, an ethyl group, a 2-methylpropyl group, and a benzyl group are more preferable.

  Compounds that can constitute the structural unit represented by the general formula (IV) include alanine, 2-aminobutyric acid, valine, norvaline, leucine, norleucine, tert-leucine, isoleucine, serine, threonine, cysteine, methionine, 2 -Α-amino acids such as phenylglycine, phenylalanine, tyrosine, histidine, tryptophan, proline and the like can be exemplified. Among these, alanine is most preferable from the viewpoints of ease of supply, inexpensive price, ease of polymerization, and low yellowness (YI) of the polymer.

<Polymerization degree of polyamide resin composition>
The preferred relative viscosity of the polyamide resin composition of the present invention is preferably 1.8 to 4.2. The relative viscosity is preferably 1.8 to 4.2, more preferably 2.0 to 4.0, and still more preferably 2.2 to 3.8 from the viewpoint of the appearance of the molded product and molding processability.
The relative viscosity here is 96% measured in the same manner as the drop time (t) measured by dissolving a polyamide resin composition 0.2 g in 20% 96% sulfuric acid at 25 ° C. with a Canon Fenceke viscometer. It is the ratio of the drop time (t ₀ ) of sulfuric acid itself, and is represented by the following formula.
Relative viscosity = t / t ₀

<Phosphorus compound (X)>
The polyamide resin composition of the present invention contains a phosphorus compound (X). As the phosphorus compound (X) used in the present invention, a phenolic calcium phosphate compound represented by the general formula (III) is preferably used. Conventionally, when polycondensating polyamide, phosphorus compounds such as sodium hypophosphite and calcium hypophosphite have been used as polyamide polycondensation catalysts. However, in the present invention, in addition to the conventional phosphorus compound, the specific phosphorus compound (X) represented by the above general formula (III) is added to the polymerization system, so that the polymerization rate is higher than that of the conventional phosphorus compound. Can be improved. Further, by adding a phosphorus compound (X) represented by the following general formula (III) into the polymerization system, an increase in the back pressure of the filter and generation of foreign matter are suppressed during subsequent molding processing, thereby improving productivity. be able to.
A suitable compound as the phosphorus compound (X) is calcium bis [3,5-di (tert-butyl) -4-hydroxybenzyl (ethoxy) phosphinate], which is available from BASF as IRGANOX1425 (trade name). It is.

The addition amount of the phosphorus compound (X) of the present invention is preferably 50 to 2000 ppm with respect to the polyamide. The lower limit is preferably 100 ppm or more, more preferably 200 ppm, and the upper limit is preferably 1500 ppm or less, more preferably 1000 ppm by mass. If the addition amount of the phosphorus compound is 50 ppm or more, the polymerization rate is improved. Moreover, if the addition amount of a phosphorus compound is 2000 ppm or less, the filter clogging at the time of shaping | molding will be reduced and continuous shaping | molding for a long time will be attained.

The phosphoric acid compound (X) of the present invention may be used in combination with a catalyst such as sodium hypophosphite or calcium hypophosphite conventionally used as a polymerization catalyst for polyamide.

The gelation time of the polyamide resin composition of the present invention is measured by a gelation test described later, and is 20 hours or longer, preferably 24 is preferably time or longer. In a polyamide resin composition having a gelation time of less than 20 hours, gelation gradually occurs in a melt molding machine in continuous molding for a long time, the melt viscosity of the melt rises, and the back pressure rises very quickly. This is a problem because the filter replacement cycle becomes very short, resulting in a decrease in productivity and economy. Moreover, the molded object from such a polyamide resin composition contains the foreign material colored by the gelled material, and a color also worsens. In particular, in stretched films and biaxially stretched hollow molded bodies obtained by stretch molding, the portions where gel-like materials exist are not normally stretched and become thick, causing unevenness in thickness and not having commercial value. Many bodies are generated and the yield may be deteriorated. In the worst case, only a molded body having no commercial value may be obtained.

  The gelation time is ideally infinite, but is preferably 500 hours or less, more preferably 200 hours or less, and particularly preferably 100 hours or less. When trying to produce a polyamide resin composition having a gelation time of 500 hours or longer, highly purified raw materials and a large amount of deterioration preventing agent are required, which is not economical. As another method, there is a method of keeping the polymerization temperature at the time of polyamide polycondensation low, but since polycondensation takes time, there may be a problem in productivity.

Since the polyamide to which the phosphorus compound (X) of the present invention is added increases the polymerization rate and the polymerization time is shortened, the resulting polyamide resin composition has a low yellowness. As for the range of yellowness of a preferable polyamide resin composition, b value is -5 or less. When the b value is −5 or less, the hue of the molded body made of the polyamide resin composition is at a level that causes no practical problems.

<Molecular weight distribution (Mw / Mn)>
The number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polyamide resin composition of the present invention can be determined by gel permeation chromatography (GPC) by the measurement method described in the examples. . The molecular weight distribution needs to be in an appropriate range since it affects the moldability, the mechanical properties of the molded body, and other physical properties. A preferable range is 1.6 to 4.0, and a more preferable range is 1.8 to 3.0.

<Production method of polyamide>
The polyamide of the present invention can be produced by polycondensing a diamine component that can constitute the diamine unit and a dicarboxylic acid component that can constitute the dicarboxylic acid unit.
The phosphorus compound (X) of the present invention is preferably added during the polycondensation reaction of polyamide. The timing of adding the phosphorus compound (X) is as follows. When a polyamide is produced by an atmospheric pressure dropping method or a pressure dropping method, which will be described later, a dicarboxylic acid component or other catalyst as a raw material for polyamide is charged into a reaction vessel at the same time. Examples thereof include a method of adding, and a method of adding the phosphorus compound (X) after the polycondensation reaction starts and after the dropwise addition of the diamine component. By setting the timing of adding the phosphorus compound (X) to the above timing, the polymerization rate of the polyamide can be improved, and the increase in back pressure and the generation of foreign matter during subsequent molding can be suppressed.
Further, a small amount of monoamine or monocarboxylic acid may be added as a molecular weight modifier during polycondensation. Further, in order to suppress the polycondensation reaction and obtain a desired degree of polymerization, the ratio (molar ratio) between the diamine component and the carboxylic acid component constituting the polyamide may be adjusted by shifting from 1.

Examples of the polyamide polycondensation method of the present invention include, but are not limited to, a reactive extrusion method, a pressurized salt method, an atmospheric pressure dropping method, and a pressure dropping method. Further, when the reaction temperature is as low as possible, yellowing and gelation of the polyamide can be suppressed, and a polyamide having a stable property can be obtained.
Examples of the polyamide polycondensation method of the present invention include, but are not limited to, a reactive extrusion method, a pressurized salt method, an atmospheric pressure dropping method, and a pressure dropping method. Among these polycondensation methods, the atmospheric pressure dropping method and the pressure dropping method are preferable.
The reaction temperature may be equal to or higher than the melting point of the polyamide, but a lower one can suppress yellowing and gelation of the polyamide (A), and a stable property polyamide can be obtained. The specific reaction temperature is preferably 180 to 300 ° C, more preferably 200 to 270 ° C. Hereinafter, a normal pressure dropping method and a pressure dropping method suitable as the polycondensation method of the polyamide of the present invention will be described.

<Normal pressure dropping method>
In the normal pressure dropping method, a diamine component is continuously added dropwise to a mixture prepared by heating and melting a dicarboxylic acid component, other components, sodium hypophosphite and sodium acetate under normal pressure, and condensed water is added. Polycondensation while removing. The polycondensation reaction is preferably carried out while raising the temperature of the reaction system so that the reaction temperature does not fall below the melting point of the polyamide to be produced. When the polyamide is produced by the atmospheric dropping method, the phosphorus compound (X) is added at the same time as adding the dicarboxylic acid component or other catalyst as a raw material of the polyamide to the reaction vessel, or by polycondensation. The method of adding phosphorus compound (X) after completion | finish of dripping of an amine component after reaction start is mentioned.
Compared with the pressurized salt method, the atmospheric pressure dropping method does not use water to dissolve the salt, so the yield per batch is large, and since there is no need to vaporize or condense the raw material components, the reaction rate is low. This is preferable because there is little decrease and the process time can be shortened.

<Pressure dropping method>
In the pressure drop method, first, a dicarboxylic acid component, other components, sodium hypophosphite and sodium acetate are charged into a polycondensation can, and the components are stirred and melt mixed to prepare a mixture. Next, while the internal pressure of the can is preferably increased to about 0.3 to 0.4 MPaG, the diamine component is continuously dropped into the mixture, and polycondensation is performed while removing condensed water. At this time, it is preferable to carry out the polycondensation reaction while raising the temperature of the reaction system so that the reaction temperature does not fall below the melting point of the produced polyamide. When the set molar ratio is reached, the addition of the diamine component is terminated, and while gradually raising the inside of the can to normal pressure, the temperature is raised to about the melting point of polyamide + 10 ° C. and maintained, and then gradually reduced to 0.02 MPaG. However, it is preferable to keep the temperature as it is and to continue the polycondensation. When a certain stirring torque is reached, the inside of the can can be pressurized with nitrogen to about 0.3 MPaG to recover the polyamide (A).
When the polyamide is produced by the pressure drop method, the phosphorus compound (X) is added at the same time as adding a dicarboxylic acid component or other catalyst as a raw material of the polyamide to the reaction vessel, or by polycondensation. A method of adding a phosphorus compound (X) when the inside of the reaction vessel is returned to normal pressure after completion of the dropwise addition of the diamine component after the start of the reaction is mentioned.

The pressure drop method is useful when a volatile component is used as a monomer, as in the pressure salt method. The pressure drop method is preferable because it can prevent the transpiration of other components, further suppress the polycondensation between other components, and can smoothly proceed the polycondensation reaction, so that a polyamide having excellent properties can be obtained. .
Furthermore, since the pressure drop method does not use water for dissolving the salt compared to the pressure salt method, the yield per batch is large, and the reaction time can be shortened as in the atmospheric pressure drop method. A polyamide having a low yellowness can be obtained.

<Process for increasing the degree of polymerization>
The polyamide produced by the polycondensation method can be used as it is, but may be subjected to a step for further increasing the degree of polymerization. Further examples of the step of increasing the degree of polymerization include reactive extrusion in an extruder and solid phase polymerization.
As the heating device used in the solid phase polymerization, a known device can be used, and a continuous heating drying device, a tumble dryer, a conical dryer, a rotary dryer or the like called a rotary drum type heating device, and a nauta mixer A conical heating device having a rotor blade inside is preferred.
Among these, a rotary drum type heating device is preferable from the viewpoint that the inside of the system can be sealed and the polycondensation can proceed in a state where oxygen that causes coloring is removed.

<Phosphorus atom-containing compound, alkali metal compound>
In the polycondensation of the polyamide of the present invention, a phosphorus atom-containing compound may be added in combination with the phosphorus compound (X) of the present invention from the viewpoint of promoting the amidation reaction.
Examples of the phosphorus atom-containing compound include phosphinic acid compounds such as dimethylphosphinic acid and phenylmethylphosphinic acid; hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, magnesium hypophosphite, Diphosphite compounds such as calcium hypophosphite and ethyl hypophosphite; phosphonic acid, sodium phosphonate, potassium phosphonate, lithium phosphonate, potassium phosphonate, magnesium phosphonate, calcium phosphonate, phenylphosphonic acid, ethylphosphone Phosphonic acid compounds such as acid, sodium phenylphosphonate, potassium phenylphosphonate, lithium phenylphosphonate, diethyl phenylphosphonate, sodium ethylphosphonate, potassium ethylphosphonate; phosphonous acid, sodium phosphonite, phosphorous acid Lithium phosphite, potassium phosphonite, magnesium phosphonite, calcium phosphonite, phenylphosphonite, sodium phenylphosphonite, potassium phenylphosphonite, lithium phenylphosphonite, ethyl phenylphosphonite, etc. Phosphonic acid compounds; phosphorous acid, sodium hydrogen phosphite, sodium phosphite, lithium phosphite, potassium phosphite, magnesium phosphite, calcium phosphite, triethyl phosphite, triphenyl phosphite, pyro-subite Examples thereof include phosphorous acid compounds such as phosphoric acid.
Among these, hypophosphite metal salts such as sodium hypophosphite, potassium hypophosphite, lithium hypophosphite and the like are particularly preferable because they are highly effective in promoting amidation reaction and excellent in anti-coloring effect. In particular, sodium hypophosphite is preferred. In addition, the phosphorus atom containing compound which can be used by this invention is not limited to these compounds.

The phosphorus atom concentration in the polyamide resin composition of the present invention is preferably 1 to 1000 ppm, more preferably 3 to 600 ppm, and still more preferably 5 to 400 ppm. When the phosphorus atom concentration in the polyamide resin composition is 1 ppm or more, the polyamide resin composition is difficult to be colored during polymerization, and the transparency is increased. If it is 1000 ppm or less, the polyamide resin composition is hardly gelled, and it is possible to reduce the mixing of fish eyes considered to be caused by the phosphorus atom-containing compound, and the appearance of the molded product becomes good.
The phosphorus atom concentration in the polyamide resin composition in the present invention is not only the phosphorus atom derived from the phosphorus compound (X) of the present invention, but also phosphorus derived from a phosphorus atom-containing compound that is a polymerization catalyst during polyamide polymerization. It shall indicate the total phosphorus atom concentration in the polyamide resin composition, including atoms.

Moreover, it is preferable to add an alkali metal compound in combination with the phosphorus compound (X) and the phosphorus atom-containing compound in the polycondensation system of polyamide. In order to prevent coloring of the polyamide during polycondensation, a sufficient amount of the phosphorus compound (X) and the phosphorus atom-containing compound must be present. In order to adjust the amidation reaction rate, it is preferable to coexist an alkali metal compound.
As the alkali metal compound, alkali metal hydroxide, alkali metal acetate, alkali metal carbonate, alkali metal alkoxide, and the like are preferable. Specific examples of the alkali metal compound that can be used in the present invention include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, lithium acetate, sodium acetate, potassium acetate, rubidium acetate, cesium acetate. Sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, potassium methoxide, lithium methoxide, sodium carbonate and the like, but can be used without being limited to these compounds. The ratio of the phosphorus atom-containing compound to the alkali metal compound is such that the phosphorus atom-containing compound / alkali metal compound = 1.0 / 0.05 to 1.0 / from the viewpoint of controlling the polymerization rate and reducing the yellowness. The range of 1.5 is preferable, more preferably 1.0 / 0.1 to 1.0 / 1.2, and still more preferably 1.0 / 0.2 to 1.0 / 1.1.

<Polyamide resin composition>
The polyamide resin composition of the present invention includes a lubricant, a crystallization nucleating agent, an anti-whitening agent, a matting agent, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, a plasticizer, depending on the required use and performance. You may add additives, such as a flame retardant, an antistatic agent, an anti-coloring agent, antioxidant, and an impact resistance improving material. These additives can be added as necessary within a range not impairing the effects of the present invention. Further, the polyamide resin composition of the present invention may be mixed with various resins according to the required use and performance to obtain a polyamide resin composition.

  A conventionally known method can be used for mixing the polyamide resin composition and the additive of the present invention, but dry mixing that is low cost and does not receive heat history is preferably performed. For example, the polyamide resin composition and said additive are put into a tumbler, and the method of mixing by rotating is mentioned. Further, in the present invention, in order to prevent classification of the polyamide resin composition and the additive after dry mixing, a method of adding and mixing the additive after adhering the viscous liquid to the polyamide resin composition as a spreading agent Can also be taken. Examples of the spreading agent include a surfactant and the like, but a known one can be used without being limited thereto.

<Oxidation reaction accelerator>
In order to impart oxygen absorption performance to the polyamide resin composition of the present invention, a conventionally known oxidation reaction accelerator may be added as long as the effects of the present invention are not impaired. The oxidation reaction accelerator can enhance the oxygen absorption performance of the oxygen absorption barrier layer by promoting the oxygen absorption performance of the polyamide. As oxidation reaction accelerators, Group VIV metals of the periodic table such as iron, cobalt and nickel, Group I metals such as copper and silver, Group IV metals such as tin, titanium and zirconium, Group V of vanadium, Examples thereof include low-valent inorganic or organic acid salts of Group VI metals such as chromium and Group VII metals such as manganese, or complex salts of the above transition metals.
In the present invention, the addition amount of the oxygen reaction accelerator is preferably 10 to 800 ppm, more preferably 50 to 600 ppm, and still more preferably 100 to 400 ppm as a metal atom concentration in the polyamide resin composition.

<Uses of polyamide resin composition>
Representative examples of the use of the polyamide resin composition of the present invention include, but are not limited to, molded materials such as packaging materials and packaging containers. The polyamide resin composition of the present invention can be processed and used as at least a part of the molded body. For example, the polyamide resin composition of the present invention can be used as at least a part of a film-like or sheet-like packaging material, and various pouches such as bottles, trays, cups, tubes, flat bags, standing pouches, etc. It can be used as at least part of a packaging container. The thickness of the layer made of the polyamide resin composition of the present invention is not particularly limited, but preferably has a thickness of 1 μm or more.

There are no particular limitations on the method for producing a molded product such as a packaging material or packaging container, and any method can be used. For example, for film-shaped or sheet-shaped packaging materials or tube-shaped packaging materials, polyamide or polyamide resin composition melted through a T-die, circular die, etc. is extruded from an attached extruder. Can do. In addition, the film-form molded object obtained by the above-mentioned method can also be processed into a stretched film by extending | stretching this. A bottle-shaped packaging container can be obtained by injecting molten polyamide or a polyamide resin composition into a mold from an injection molding machine to produce a preform, and then heating to a stretching temperature to perform blow stretching.
Containers such as trays and cups are manufactured by injecting a molten polyamide resin composition into a mold from an injection molding machine, or by forming a sheet-like packaging material by a molding method such as vacuum molding or pressure molding. Can be obtained. The packaging material and the packaging container can be manufactured through various methods regardless of the above-described manufacturing method.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

  Measurement of the relative viscosity, yellowness, molecular weight and molecular weight distribution, glass transition temperature and melting point, prephosphorus atom content of the polyamide obtained in the examples, and gelation time of the unstretched film made from the obtained polyamide are as follows. It was done by the method.

(1) 0.2 g of relative viscosity polyamide was precisely weighed and dissolved in 20 ml of 96% sulfuric acid at 20-30 ° C. with stirring. After completely dissolving, 5 ml of the solution was quickly taken into a Cannon-Fenceke viscometer and allowed to stand for 10 minutes in a constant temperature bath at 25 ° C., and then the drop time (t) was measured. Further, the dropping time (t ₀ ) of 96% sulfuric acid itself was measured in the same manner. It was calculated relative viscosity by the following equation from t and t _0.
Relative viscosity = t / t ₀

(2) Yellowness (b value)
About the pellet of the polyamide resin composition obtained by the Example and the comparative example, it measured by the permeation | transmission method according to ASTMD1003 using Z-Σ80 color difference meter (made by Nippon Denshoku Industries Co., Ltd.).

(3) Molecular weight and molecular weight distribution (Mw / Mn)
The number average molecular weight (Mn), the weight average molecular weight (Mw), and the molecular weight distribution (Mw / Mn) can be determined by gel permeation chromatography (GPC). Specifically, “HLC-8320GPC” manufactured by Tosoh Corporation was used as an apparatus, and two “TSK gel Super HM-H” manufactured by Tosoh Corporation were used as columns. The eluent is prepared by preparing hexafluoroisopropanol (HFIP) having a sodium trifluoroacetate concentration of 10 mmol / l as a solvent, and preparing an eluent having a sample concentration of 0.02% by mass, a column temperature of 40 ° C., a flow rate of 0.3 ml / min, The measurement was performed under the condition of a refractive index detector (RI).
In addition, the number average molecular weight (Mn), the weight average molecular weight (Mw), and the molecular weight distribution (Mw / Mn) were determined as standard polymethyl methacrylate equivalent values.

(4) Differential scanning calorimetry (glass transition temperature and melting point)
The differential scanning calorific value was measured according to JIS K7121 and K7122. Using a differential scanning calorimeter (manufactured by Shimadzu Corporation, trade name: “DSC-60”), each sample was charged into a DSC measurement pan, and the temperature was increased to 300 ° C. at a heating rate of 10 ° C./min in a nitrogen atmosphere Measurements were made after pretreatment with warming and rapid cooling. The measurement conditions were a temperature rising rate of 10 ° C./min, holding at 300 ° C. for 5 minutes, and then measuring to a temperature falling rate of −5 ° C./min up to 100 ° C. to determine a glass transition temperature Tg and a melting point Tm.

(5) Total phosphorus atom content The phosphorus atom content in the polyamide resin compositions obtained in the examples and comparative examples was measured by the method described below.
The sample was subjected to dry ashing decomposition in the presence of sodium carbonate, or wet decomposition in sulfuric acid / nitric acid / perchloric acid system or sulfuric acid / hydrogen peroxide system, and phosphorus was converted to normal phosphoric acid. Next, the orthophosphoric acid is reacted with molybdate in a 1 mol / L sulfuric acid solution to form phosphomolybdic acid, which is reduced with hydrazine sulfate, and the absorbance of the resulting heteropoly blue at 830 nm is measured with an absorptiometer (Shimadzu). The phosphorous atom content in the polyamide resin composition was determined by colorimetric quantification by measurement with Seiko Seisakusho, UV-150-02).

(6) Gelation test (gel fraction and gelation time)
A non-stretched film with a thickness of 250 μm using a single-screw extruder composed of a rapid compression full flight screw with L / D = 15 and an apparatus composed of a T die under a molding condition of 265 ° C. and a rotational speed of 50 rpm. Prototyped. Subsequently, the four films were stacked and cut into a circle having a diameter of about 40 mm, and then sandwiched between Teflon (registered trademark) sheets. The sheets were sandwiched between metal plates, and the metal plates were fixed with bolts. Then, it pressed with the pressure of 50 kg / cm < ² > on the hot press heated at 290 degreeC, and heated for the predetermined time. After heating for a predetermined time, the metal plate was taken out, rapidly cooled, and taken out at room temperature.
Next, 100 mg of this sample was weighed and placed in a test tube capable of being sealed, and the sample was dried at 60 ° C. for 30 minutes in a constant temperature dryer (the mass at this time is referred to as “sample mass”). Immediately after the sample was dried, 10 ml of hexafluoroisopropanol (manufactured by Junsei Chemical Co., Ltd., hereinafter sometimes referred to as “HFIP”) was added to the test tube, covered, left to stand for 24 hours, and dissolved. The obtained HFIP solution was filtered under reduced pressure through a Teflon (registered trademark) membrane filter having a pore size of 0.3 μm and weighed in advance, and the residue remaining on the membrane filter was washed with HFIP. Thereafter, the filter with the residue attached was naturally dried for 24 hours.
Subsequently, the dried residue and the total mass of the filter are weighed, and the amount of HFIP insoluble component (gel mass) of the retained sample is determined from the difference between the weight of the membrane filter weighed in advance, and the retained sample before HFIP immersion (sample mass) The gel fraction was calculated by the following formula (1) divided by.
Gel fraction (%) = (gel mass / sample mass) × 100 (1)
Moreover, the heating time in a hot press machine was changed, and the maximum time when the gel fraction was 0% was defined as the gel time.

Example 1
Weighed precisely in a pressure-resistant reaction vessel with an internal volume of 50 L equipped with a stirrer, partial condenser, full condenser, pressure regulator, thermometer, dripping tank and pump, aspirator, nitrogen inlet pipe, bottom exhaust valve, and strand die. Adipic acid (AA) (Asahi Kasei Chemicals Corporation) 13000 g (88.95 mol), sodium hypophosphite 11.3 g (0.11 mol), sodium acetate 5.85 g (0.07 mol), and calcium bis [3 , 5-di (tert-butyl) -4-hydroxybenzyl (ethoxy) phosphinate] 6.57 g (300 ppm as the concentration of compound (X) with respect to 21.9 kg of the theoretical yield of polyamide) The inside of the reaction vessel was sealed, and the temperature was raised to 170 ° C. with stirring while keeping the inside of the vessel at 0.4 MPa. After reaching 170 ° C., 12042.6 g (88.42 mol) of metaxylylenediamine (MXDA) (manufactured by Mitsubishi Gas Chemical Co., Ltd.) stored in the dropping tank was started to the molten raw material in the reaction vessel. The reaction vessel was continuously heated to 260 ° C. while removing condensed water produced outside the system while keeping the inside of the vessel at 0.4 MPa. After completion of the dropwise addition of metaxylylenediamine, the inside of the reaction vessel was gradually returned to normal pressure, and then the inside of the reaction vessel was reduced to 80 kPa using an aspirator to remove condensed water. After observing the stirring torque of the stirrer during decompression, stop stirring when the specified torque is reached, pressurize the inside of the reaction tank with nitrogen, open the bottom drain valve, extract the polymer from the strand die and form a strand Cooled and pelletized with a pelletizer. The addition of the calcium phosphate compound had no effect on the torque increase rate.

Next, this pellet was charged into a stainless steel drum-type heating device and rotated at 5 rpm. The atmosphere in the reaction system was raised from room temperature to 140 ° C. under a small nitrogen flow. When the reaction system temperature reached 140 ° C., the pressure was reduced to 0.3 torr, and the system temperature was further increased to 180 ° C. in 110 minutes. From the time when the system temperature reached 180 ° C., the solid state polymerization reaction was continued at the same temperature for 180 minutes. In the middle, 100 g pellets were extracted from the sample extraction valve every 30 minutes, and the degree of polymerization was measured. The degree of polymerization of the polyamide resin composition was measured with a capillograph (Toyo Seiki Co., Ltd. Capillograph 1D) at 260 ° C. for 6 minutes, and then measured for the melt viscosity in the range from 61 sec ^{−1 to} 3648 sec ^−1. The reaction was terminated when the melt viscosity at 122 sec ⁻¹ exceeded 650 Pa · s. The reaction time was 2 hours and 40 minutes. After completion of the reaction, the decompression was terminated, the system temperature was lowered under a nitrogen stream, and the pellet was taken out when the temperature reached 60 ° C. to obtain an MXDA / AA polymer (polyamide resin composition 1). In addition, the preparation composition ratio of each monomer was metaxylylenediamine: adipic acid = 49.8: 50.2 (mol%).

Example 2
Weighed precisely in a pressure-resistant reaction vessel with an internal volume of 50 L equipped with a stirrer, partial condenser, full condenser, pressure regulator, thermometer, dripping tank and pump, aspirator, nitrogen inlet pipe, bottom exhaust valve, and strand die. Adipic acid (AA) (manufactured by Asahi Kasei Chemicals Corporation) 13000 g (88.95 mol), sodium hypophosphite 11.3 g (0.11 mol), sodium acetate 5.85 g (0.07 mol), fully substituted with nitrogen After that, the inside of the reaction vessel was sealed, and the temperature was raised to 170 ° C. with stirring while keeping the inside of the vessel at 0.4 MPa. After reaching 170 ° C., 12042.6 g (88.42 mol) of metaxylylenediamine (MXDA) (manufactured by Mitsubishi Gas Chemical Co., Inc.) stored in the dropping tank was started to be added to the molten raw material in the reaction vessel, While removing the condensed water produced outside the system while maintaining the inside of the vessel at 0.4 MPa, the temperature in the reaction vessel was continuously raised to 260 ° C. After completion of the dropwise addition of metaxylylenediamine, the inside of the reaction vessel was gradually returned to normal pressure. Thereafter, 19.71 g of calcium bis [3,5-di (tert-butyl) -4-hydroxybenzyl (ethoxy) phosphinate] (compound for the theoretical yield of 21.9 kg of the polyamide resin composition) against the expected yield of 21.9 kg (X) As a concentration, 900 ppm) was added and stirred for 10 minutes, and then the reaction vessel was depressurized to 80 kPa using an aspirator to remove condensed water. After observing the stirring torque of the stirrer during decompression, stop stirring when the specified torque is reached, pressurize the inside of the reaction tank with nitrogen, open the bottom drain valve, extract the polymer from the strand die and form a strand Cooled and pelletized with a pelletizer. The addition of the calcium phosphate compound had no effect on the torque increase rate. Next, this pellet was charged into a stainless steel drum-type heating device and rotated at 5 rpm. The atmosphere in the reaction system was raised from room temperature to 140 ° C. under a small nitrogen flow. When the reaction system temperature reached 140 ° C., the pressure was reduced to 0.3 torr, and the system temperature was further increased to 180 ° C. in 110 minutes. From the time when the system temperature reached 180 ° C., the solid state polymerization reaction was continued at the same temperature for 180 minutes. On the way, 100 g pellets were extracted from the sample extraction valve every 30 minutes, and retained at 260 ° C. for 6 minutes in a capillograph (Toyo Seiki Co., Ltd. Capillograph 1D), and then a shear rate, a range from 61 sec ^{−1 to} 3648 sec ^−1. Then, the melt viscosity was measured, and the reaction was terminated when the melt viscosity at 122 sec ⁻¹ exceeded 650 Pa · s. The reaction time was 2 hours and 20 minutes. After completion of the reaction, the decompression was terminated, the system temperature was lowered under a nitrogen stream, and the pellet was taken out when the temperature reached 60 ° C. to obtain an MXDA / AA polymer (polyamide 2). In addition, the preparation composition ratio of each monomer was metaxylylenediamine: adipic acid = 49.8: 50.2 (mol%).

Example 3
Weighed precisely in a pressure-resistant reaction vessel with an internal volume of 50 L equipped with a stirrer, partial condenser, full condenser, pressure regulator, thermometer, dripping tank and pump, aspirator, nitrogen inlet pipe, bottom exhaust valve, and strand die. Adipic acid (manufactured by Asahi Kasei Chemicals Corporation) 13000 g (88.95 mol), high-purity isophthalic acid (manufactured by AGI International Chemical Co., Ltd.) 943.3 g (5.68 mol), sodium hypophosphite 2.40 g (0.023 mol) and sodium acetate 1.25 g (0.015 mol) were added and sufficiently purged with nitrogen. Then, the reaction vessel was sealed, and the vessel was kept at 0.4 MPa while stirring up to 170 ° C. After reaching 170 ° C., 12811.8 g (9 of metaxylylenediamine (manufactured by Mitsubishi Gas Chemical Co., Inc.)) stored in the dropping tank into the molten raw material in the reaction vessel. 0.07 mol) was started to drop and the inside of the reaction vessel was continuously heated to 260 ° C. while removing condensed water produced outside the system while keeping the inside of the container at 0.4 MPa. Thereafter, the inside of the reaction vessel was gradually returned to normal pressure, and then 21.05 g of calcium bis [3,5-di (tert-butyl) -4-hydroxybenzyl (ethoxy) phosphinate] with respect to the expected yield of 23.3 Kg. (900 ppm as the concentration of compound (X) with respect to 23.3 kg of the theoretical yield of polyamide) was added and stirred for 10 minutes, and then the reaction vessel was decompressed to 80 kPa using an aspirator to remove condensed water. Observe the stirring torque of the machine, stop stirring when the specified torque is reached, pressurize the inside of the reaction tank with nitrogen, open the bottom drain valve, extract the polymer from the strand die, and The pellets were cooled and pelletized with a pelletizer, and the torque increase rate was not affected by the addition of the calcium phosphate compound.The pellets were then placed in a stainless steel drum-type heating device and rotated at 5 rpm. The atmosphere in the reaction system was raised from room temperature to 140 ° C. under a small amount of nitrogen stream, and when the reaction system temperature reached 140 ° C., the pressure was reduced to 0.3 torr. The internal temperature was raised to 180 ° C. over 110 minutes, and the solid-state polymerization reaction was continued for 180 minutes at the same temperature from the time when the internal temperature reached 180 ° C. From the sample extraction valve every 30 minutes along the way. withdrawn 100g pellet at capillograph (manufactured by Toyo Seiki Co. Capillograph 1D), after staying 260 ° C. 6 minutes, the shear rate, 61Sec ^- Measuring the melt viscosity in the range up to ~3648sec ^-1, the melt viscosity at 122 sec ^-1 point the reaction was terminated at the point beyond 650 Pa · s. The reaction time was 2 hours 30 minutes. After completion of the reaction, the decompression was terminated, the system temperature was lowered under a nitrogen stream, and the pellet was taken out when the temperature reached 60 ° C., thereby obtaining an MXDA / AA / PIA polymer (polyamide 3).
In addition, the preparation composition ratio of each monomer was metaxylylenediamine: adipic acid: high purity isophthalic acid = 49.9: 44.1: 6.0 (mol%).

Comparative Example 1
Weighed precisely in a pressure-resistant reaction vessel with an internal volume of 50 L equipped with a stirrer, partial condenser, full condenser, pressure regulator, thermometer, dripping tank and pump, aspirator, nitrogen inlet pipe, bottom exhaust valve, and strand die. Adipic acid (AA) (manufactured by Asahi Kasei Chemicals Corporation) 13000 g (88.95 mol), sodium hypophosphite 11.3 g (0.11 mol), sodium acetate 5.85 g (0.07 mol) were added, and nitrogen was sufficiently added. After the replacement, the inside of the reaction vessel was sealed, and the temperature was raised to 170 ° C. with stirring while keeping the inside of the vessel at 0.4 MPa. After reaching 170 ° C., 12042.6 g (88.42 mol) of metaxylylenediamine (MXDA) (manufactured by Mitsubishi Gas Chemical Co., Inc.) stored in the dropping tank was started to be added to the molten raw material in the reaction vessel, While removing the condensed water produced outside the system while maintaining the inside of the vessel at 0.4 MPa, the temperature in the reaction vessel was continuously raised to 260 ° C. After completion of the dropwise addition of metaxylylenediamine, the inside of the reaction vessel was gradually returned to normal pressure, and then the inside of the reaction vessel was reduced to 80 kPa using an aspirator to remove condensed water. After observing the stirring torque of the stirrer during decompression, stop stirring when the specified torque is reached, pressurize the inside of the reaction tank with nitrogen, open the bottom drain valve, extract the polymer from the strand die and form a strand Cooled and pelletized with a pelletizer. Next, this pellet was charged into a stainless steel drum-type heating device and rotated at 5 rpm. The atmosphere in the reaction system was raised from room temperature to 140 ° C. under a small nitrogen flow. When the reaction system temperature reached 140 ° C., the pressure was reduced to 0.3 torr, and the system temperature was further increased to 180 ° C. in 110 minutes. On the way, 100 g pellets were extracted from the sample extraction valve every 60 minutes, put in an aluminum bag and heat-sealed. From the time when the system temperature reached 180 ° C., the solid state polymerization reaction was continued at the same temperature for 180 minutes. On the way, 100 g pellets were extracted from the sample extraction valve every 30 minutes, and retained at 260 ° C. for 6 minutes in a capillograph (Toyo Seiki Co., Ltd. Capillograph 1D), and then a shear rate, a range from 61 sec ^{−1 to} 3648 sec ^−1. Then, the melt viscosity was measured, and the reaction was terminated when the melt viscosity at 122 sec ⁻¹ exceeded 650 Pa · s. The reaction time was 3 hours. After completion of the reaction, the decompression was terminated, the system temperature was lowered under a nitrogen stream, and the pellet was taken out when the temperature reached 60 ° C. to obtain an MXDA / AA polymer (polyamide 4). In addition, the preparation composition ratio of each monomer was metaxylylenediamine: adipic acid = 49.8: 50.2 (mol%).

  Table 1 shows the relative viscosity, yellowness (b value) of polyamide, molecular weight and molecular weight distribution, glass transition temperature and melting point, total phosphorus atom concentration, and gelation test of unstretched film prepared from the obtained polyamide resin composition. The results are shown.

  The polyamide resin compositions of Examples 1 to 3 to which calcium bis [3,5-di (tert-butyl) -4-hydroxybenzyl (ethoxy) phosphinate] was added as the phosphorus compound (X) of the present invention were added. Compared with Comparative Example 1 that was not present, the polymerization reaction time was short, resulting in good yellowness and molecular weight distribution. Further, the polyamide resin composition of the present invention had a long time to gelation and was excellent in properties.

  The polyamide resin composition of the present invention has a small increase in the back pressure of the filter at the time of molding, and has good thermal stability and thermal oxidation stability at the time of drying and molding, so it has excellent color tone and is colored in the molding process. Since it is difficult to generate foreign substances such as gels, it can be used for all purposes.

Claims (9)

A diamine unit containing 70 mol% or more of an aromatic diamine unit represented by the following general formula (I), a linear aliphatic dicarboxylic acid unit represented by the following general formula (II-1) and / or the following general formula ( A polyamide resin composition obtained by adding a phosphorus compound (X) represented by the following general formula (III) to a polyamide containing a dicarboxylic acid unit containing 50 mol% or more of the aromatic dicarboxylic acid unit represented by II-2).

[In said general formula (II-1), n represents the integer of 2-18. In the general formula (II-2), Ar represents an arylene group.

The polyamide resin composition according to claim 1, wherein the addition amount of the phosphorus compound (X) is 50 to 2000 ppm with respect to the polyamide. The polyamide resin composition according to claim 1 or 2, wherein the phosphorus atom concentration is 1-1000 ppm. The polyamide resin composition according to any one of claims 1 to 3, wherein the molecular weight distribution (Mw / Mn) is 1.6 or more and 4.0 or less. b value is -5 or less, The polyamide resin composition in any one of Claims 1-4. The polyamide resin composition according to any one of claims 1 to 5, having a relative viscosity of 1.8 or more and 4.2 or less. The polyamide resin composition according to any one of claims 1 to 6, wherein the gelation time of the melt residence test is 20 hours or more.   A packaging material and a packaging container using the polyamide resin composition according to claim 1.   An industrial material and an industrial part obtained by using the polyamide resin composition according to claim 1.