JP2014177548A - Method for producing polyamide resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To polymerize a polyamide resin having a predetermined molecular weight using an extruder without causing process trouble.SOLUTION: A polyamide resin (A) having a relative viscosity of 1.5-3.0 is melted and kneaded using an extruder comprising a co-rotating intermeshing twin screw and having at least one or more vacuum vents VV1, VV2 to obtain a polyamide resin (B) polymerized by polycondensation. A pressure reducing element Y is provided in a part closer to the supply part side than a barrel provided with the vacuum vent VV1 or VV2, and an area in a range of 30-70% of the whole screw length is a vacuum area VA of 300 torr or lower.

Description

  The present invention relates to a method for producing a polyamide resin in which a polyamide resin is polymerized by a polycondensation reaction by melt kneading using an extruder composed of a co-rotating meshing twin screw.

  Polyamide is excellent in mechanical properties and processability and has a relatively high gas barrier property, so it can be used not only as an injection molding material for automobiles and electrical and electronic parts, but also for packaging materials such as food, beverages, chemicals and electronic parts. It is also widely used as an industrial material. For example, a polyamide obtained from a polycondensation reaction between xylylenediamine and an aliphatic dicarboxylic acid has high strength and elastic modulus, and low permeability to gaseous substances such as oxygen, carbon dioxide, odor and flavor. Therefore, it is widely used as a gas barrier material in the field of packaging materials. Further, since it has resistance and gas barrier properties against alcohol, weakly alkaline chemicals, weakly acidic chemicals, fuel, various organic solvents, industrial gases, etc., it is also widely used in industrial fields.

Various methods for producing a polyamide resin are known. For example, after a polycarboxylic acid component and a diamine component are polycondensed by a melt polycondensation method to obtain a polyamide resin, the polyamide resin is solidified by a heat drying apparatus such as a tumble dryer. A method for increasing the degree of polymerization of polyamide by phase polymerization is known. However, the solid-phase polymerization method has a problem in that a resin having a high melting point is produced and there is a limit to increasing the molecular weight of a resin having low crystallinity, and a resin having a high melting point cannot be obtained.
On the other hand, a method is known in which a polyamide resin obtained by polycondensation of a dicarboxylic acid component and a diamine component is further polycondensed by melt kneading using an extruder having a twin screw to obtain a polyamide resin. (For example, refer to Patent Document 1). In an extruder having a twin screw, the raw material can be melt-kneaded in a short time, can be produced even with a high melting point polyamide resin, and has the advantage of being able to handle a small variety of products due to self-cleaning properties. is there. For this reason, various methods for producing various types of polyamide resins by an extruder having a twin screw have been studied.

JP 2012-188557 A

However, even if an attempt is made to polymerize the polyamide resin, which has been polymerized to some extent by the melt condensation method, with an extruder, the polycondensation reaction may not sufficiently proceed in a normal kneading operation.
Further, the polyamide resin may have a relatively high melting point depending on the type and molecular weight, and it may take time to melt in the extruder. Therefore, there may be a problem in the process such that the polyamide resin charged as a raw material is sucked into the vent without being melted to cause clogging.

  The present invention has been made in view of the above-described problems, and the object of the present invention is to provide a process in an extruder comprising a twin screw, even when a relatively high molecular weight polyamide resin is used as a raw material. An object of the present invention is to provide a method for producing a polyamide resin capable of sufficiently polymerizing the polyamide resin without causing the above problems.

As a result of intensive studies, the inventors focused on the vacuum region in the barrel formed by being sucked from the vacuum vent, and when the molecular weight of the resin charged into the extruder falls within a certain range, It has been found that by setting the length within a predetermined range, the polyamide resin can be sufficiently polymerized without causing problems in the process, and the following present invention has been achieved.
That is, the present invention provides the following (1) to (10).
(1) An aromatic diamine unit represented by the following general formula (I-1), an alicyclic diamine unit represented by the following general formula (I-2), and a fat represented by the following general formula (I-3) A diamine unit containing 70 mol% or more of a diamine unit selected from an aliphatic diamine unit, a linear aliphatic dicarboxylic acid unit represented by the following general formula (II-1), and a general formula (II-2) A polyamide resin (A) containing a dicarboxylic acid unit containing 50 mol% or more of a dicarboxylic acid unit selected from the aromatic dicarboxylic acid units is polycondensed to give a higher molecular weight polyamide resin than the polyamide resin (A) ( B) a method for producing a polyamide resin comprising:
In the production method, a polyamide resin (A) having a relative viscosity of 1.5 to 2.4 is used by using an extruder having at least one vacuum vent and including a co-rotating meshing twin screw. By polycondensation by melt kneading to produce a polyamide resin (B) having a higher molecular weight than the polyamide resin (A),
A method for producing a polyamide resin, wherein a pressure-lowering element is provided at a position closer to the supply unit than a position where the vacuum vent is provided, and a range of 30 to 70% of the total screw length is a vacuum region of 300 torr or less.
[[In the general formula (I-3), m represents an integer of 2 to 18.] In the general formula (II-1), n represents an integer of 2 to 18. In the general formula (II-2), Ar represents an arylene group. ]
(2) The manufacturing method of the polyamide resin as described in said (1) whose moisture content of the said polyamide resin (A) is 2 mass% or less.
(3) The method for producing a polyamide resin according to the above (1) or (2), wherein the relative viscosity of the polyamide resin (B) is 2.5 to 4.0.
(4) The method for producing a polyamide resin according to any one of (1) to (3), wherein the polyamide resin (A) is a compound in which a phosphorus compound is blended at a phosphorus atom concentration of 10 to 500 ppm.
(5) The manufacturing method of the polyamide resin in any one of said (1)-(4) which arrange | positions an open vent to the supply part side rather than the said vacuum area | region.
(6) Manufacture of the polyamide resin in any one of said (1)-(5) which provides the kneading part which knead | mixes the said polyamide resin (A) in the position on the supply part side rather than the said vacuum area | region. Method.
(7) The polyamide resin according to any one of (1) to (6), wherein at least one vacuum vent is provided within a range of 25% or less of the total screw length from the die side end of the extruder. Manufacturing method.
(8) The polyamide resin according to any one of (1) to (7), wherein a kneading element having a strong distribution and mixing property is provided within a range of 25% or less of the total screw length from the die side end of the extruder. Manufacturing method.
(9) The above-mentioned (1) to (8), wherein a kneading part for kneading the polyamide resin (A) is provided at a position closer to the supply part than the vacuum region, and the kneading part includes a kneading element having strong dispersion and mixing properties. The manufacturing method of the polyamide resin in any one.
(10) A group formed from a polyamide resin (B) produced by the method for producing a polyamide resin according to any one of (1) to (9) above and comprising a packaging material, a packaging container, an industrial material and an industrial part Article selected from.

  In the present invention, a high-molecular-weight polyamide resin can be produced by polymerizing a raw material polyamide resin having a predetermined molecular weight without causing problems in the process.

It is the schematic which shows the extruder used by this invention. It is a perspective view which shows the kneading disc used by this invention. 3A and 3B are perspective views showing a rotor used in the present invention, in which FIG. 3A shows a continuous rotor and FIG. 3B shows a discontinuous rotor. It is sectional drawing and the side view which show the SME mixing element used by this invention. It is a side view which shows the mixing gear used by this invention. It is sectional drawing and the side view which show the ZME mixing element used by this invention. It is the schematic which shows the extruder used in Example 1,2. It is the schematic which shows the extruder used in Examples 3-7. 2 is a schematic view showing an extruder used in Comparative Example 1. FIG. 6 is a schematic view showing an extruder used in Comparative Example 2. FIG.

The present invention is a method for producing a polyamide in which a polyamide resin (A) is polycondensed to produce a polyamide resin (B) having a higher molecular weight than the polyamide resin (A).
Hereinafter, the present invention will be described in more detail.
<Polyamide resin (A)>
The polyamide resin (A) used as a raw material in the present invention is a polyamide resin (A) containing a diamine unit and a dicarboxylic acid unit.
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. When the content of the dicarboxylic acid unit is in the range of ± 2 mol% of the content of the diamine unit, the degree of polymerization of the polyamide resin tends to increase, the polymerization can be completed in a relatively short time, and thermal deterioration does not easily occur.
The polyamide resin (A) may further contain a constituent unit other than the diamine unit and the dicarboxylic acid unit as long as the effects of the present invention are not impaired. The content of structural units other than diamine units and dicarboxylic acid units is, for example, 20 mol% or less, preferably 10 mol% or less, more preferably 5 mol% or less, but it is better not to contain them.

[Diamine unit]
The diamine unit in the polyamide resin (A) is an aromatic diamine unit represented by the following general formula (I-1), an alicyclic diamine unit represented by the following general formula (I-2), and the following general formula ( 70 mol% or more of diamine units selected from the aliphatic diamine units represented by I-3) are contained. The content is preferably 80 mol% or more, more preferably 90 mol% or more, and the upper limit is 100 mol%.

[In General Formula (I-3), m represents an integer of 2 to 18. ]

Examples of the compound that can constitute the aromatic diamine unit represented by the general formula (I-1) include orthoxylylenediamine, metaxylylenediamine, and paraxylylenediamine. These can be used alone or in combination of two or more.
Examples of the compound that can constitute the alicyclic diamine unit represented by the general formula (I-2) include bis (amino) such as 1,3-bis (aminomethyl) cyclohexane and 1,4-bis (aminomethyl) cyclohexane. Methyl) cyclohexanes. These can be used alone or in combination of two or more.
Bis (aminomethyl) cyclohexanes have structural isomers, but by increasing the cis isomer ratio, the polyamide resin has high crystallinity and good moldability. On the other hand, if the cis body ratio is lowered, a transparent polyamide resin having low crystallinity can be obtained. Therefore, when it is desired to increase the crystallinity, the cis-isomer content ratio in the bis (aminomethyl) cyclohexane is preferably 70 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol% or more. . On the other hand, when it is desired to lower the crystallinity, the trans content in the bis (aminomethyl) cyclohexane is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 70 mol% or more. .

In general formula (I-3), m represents an integer of 2 to 18, preferably 3 to 16, more preferably 4 to 14, and still more preferably 6 to 12.
As a compound that can constitute the linear aliphatic diamine unit represented by the general formula (I-3), ethylenediamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, Aliphatic diamines such as octamethylene diamine, nonamethylene diamine, decamethylene diamine, undecamethylene diamine, and dodecamethylene diamine can be exemplified, but are not limited thereto. Among these, nonamethylenediamine and decamethylenediamine are preferable. These can be used alone or in combination of two or more.

  As the diamine unit in the polyamide resin (A), in addition to imparting excellent gas barrier properties to the polyamide resin (B), the transparency and color tone are improved and the moldability of a general-purpose thermoplastic resin is facilitated. From the viewpoint, it is preferable to include at least one of an aromatic diamine unit represented by the general formula (I-1) and an alicyclic diamine unit represented by the general formula (I-2). Moreover, it is preferable that the linear aliphatic diamine unit represented by general formula (I-3) is included from a viewpoint which provides moderate crystallinity to a polyamide resin (B). Furthermore, it is preferable that the aromatic diamine unit represented by general formula (I-1) is included from a viewpoint of the property of oxygen absorption performance or a polyamide resin (B).

  The diamine unit in the polyamide resin (A) is a metaxylylenediamine unit from the viewpoint of facilitating the moldability of a general-purpose thermoplastic resin in addition to exhibiting excellent gas barrier properties in the polyamide resin (B). The content is preferably 70 mol% or more, and the content is more preferably 80 mol% or more, still more preferably 90 mol% or more, and the upper limit is 100 mol%.

  As a compound that can constitute a diamine unit other than the diamine unit represented by any one of the general formulas (I-1) to (I-3), an aromatic diamine such as paraphenylenediamine, 1,3-diaminocyclohexane, Aliphatic diamines such as 1,4-diaminocyclohexane, aliphatics such as N-methylethylenediamine, 2-methyl-1,5-pentanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane Examples include diamines, polyether diamines having ether bonds represented by Huntsman's Jeffamine and Elastamine (both trade names), but are 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 resin (A) is a linear aliphatic dicarboxylic acid unit represented by the following general formula (II-1) from the viewpoints of the reactivity during polymerization and the crystallinity and moldability of the polyamide resin. And dicarboxylic acid units selected from aromatic dicarboxylic acid units represented by the following general formula (II-2) in a total of 50 mol% or more in the dicarboxylic acid units. The content is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and the upper limit is 100 mol%.

[In General Formula (II-1), n represents an integer of 2 to 18. In general formula (II-2), Ar represents an arylene group. ]

The linear aliphatic dicarboxylic acid unit represented by the general formula (II-1) gives the polyamide resin (B) an appropriate glass transition temperature and crystallinity, as well as the flexibility required for packaging materials and packaging containers. It is preferable at the point which can provide property.
In 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, 1,10 Examples include -decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, but are not limited thereto. 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 resin (A), in addition to imparting excellent gas barrier properties to the polyamide resin (B), from the viewpoint of maintaining heat resistance after heat sterilization of packaging materials and packaging containers. It is preferable that at least one selected from the group consisting of an adipic acid unit, a sebacic acid unit, and a 1,12-dodecanedicarboxylic acid unit is contained in a total of 50 mol% or more in the linear aliphatic dicarboxylic acid unit, The content is more preferably 70 mol% or more, still more preferably 80 mol% or more, particularly preferably 90 mol% or more, and the upper limit is 100 mol%.

  The linear aliphatic dicarboxylic acid unit in the polyamide resin (A) is a linear aliphatic unit from the viewpoint of gas barrier properties of the polyamide resin (B) and thermal properties such as an appropriate glass transition temperature and melting point. It is preferable to contain 50 mol% or more in the dicarboxylic acid unit. In addition, the linear aliphatic dicarboxylic acid unit in the polyamide resin (A) is converted from the sebacic acid unit to the linear aliphatic dicarboxylic acid unit from the viewpoint of imparting appropriate gas barrier properties and molding processability to the polyamide resin (B). When the polyamide resin (B) is used for applications requiring low water absorption, weather resistance, and heat resistance, the 1,12-dodecanedicarboxylic acid unit is a linear aliphatic group. It is preferable to contain 50 mol% or more in the dicarboxylic acid unit.

The aromatic dicarboxylic acid unit represented by the general formula (II-2) may facilitate molding processability of packaging materials and packaging containers in addition to imparting further gas barrier properties to the polyamide resin (B). It is preferable in that it can be performed.
In 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. Absent. 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 resin (A) 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 more preferably 70 mol% or more, still more preferably 80 mol% or more, particularly preferably 90 mol% or more, and the upper limit is 100 mol%. It is. 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, when the total of both units is 100, the molar ratio is preferably 0/100 to 100/0, more preferably 0/100 to 60/40, More preferably, it is 0 / 100-40 / 60, More preferably, it is 0 / 100-30 / 70.

  In the dicarboxylic acid unit in the polyamide resin (A), 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 particularly limited. Rather, it is determined appropriately according to the application. For example, when the purpose is to increase the glass transition temperature of the polyamide resin (B) to lower the crystallinity of the polyamide resin (B), the linear aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit is both units. When the total is 100, the molar ratio is preferably 0/100 to 60/40, more preferably 0/100 to 40/60, and still more preferably 0/100 to 30/70. When the purpose is to lower the glass transition temperature of the polyamide resin (B) to give the polyamide resin (B) flexibility, the linear aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit is When the total is 100, the molar ratio is preferably 40/60 to 100/0, more preferably 60/40 to 100/0, and still more preferably 70/30 to 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, and 1,3-benzene. Examples of the dicarboxylic acid include diacetic acid and 1,4-benzenediacetic acid, but are not limited thereto.

[Relative viscosity of polyamide resin (A)]
In the present invention, the relative viscosity of the raw material polyamide resin (A) is 1.5 to 3.0. In the present invention, the polyamide resin (B) is produced by polymerizing the polyamide resin (A) without causing problems in the process by the production method described later because the relative viscosity is within the above range. Can do.
In the present invention, when the relative viscosity is less than 1.5, the polycondensation reaction proceeds rapidly in the extruder to increase the amount of dehydration. For example, the raw material is sucked together with water by a vacuum vent described later, and clogging and the like. May occur. In addition, if the relative viscosity is greater than 3.0, in the first place, a problem of requiring a long polymerization time or coloring in the melt polymerization tends to occur, and the polycondensation reaction may not sufficiently proceed in the extruder. is there.
The relative viscosity is preferably 1.5 to 2.5 from the above viewpoint.

[Moisture content of polyamide resin (A)]
It is preferable that the moisture content of the polyamide resin (A) which is a raw material of this invention will be 2 mass% or less. By setting the moisture content to 2% by mass or less, it is possible to prevent a large amount of water from being sucked into the vacuum vent of the extruder or a large amount of water from being blown out from the open vent during the production process of the polyamide resin (A). It is possible to make it difficult to cause problems in the process.
In the present invention, the moisture content of the polyamide resin (A) as a raw material is more preferably 1.8% by mass or less, and still more preferably 1.5% by mass or less. Further, the moisture content is not particularly limited, but is preferably 0.2% by mass or more from the viewpoint of improving the efficiency of the process, for example, drying after the polyamide resin (A) can be produced in a short time, and 0.5% by mass. The above is more preferable.

[Yellowness of polyamide resin (A)]
The yellowness of the polyamide resin (A) that is a raw material of the present invention is preferably 10 or less, more preferably 7 or less. By reducing the yellowness of the raw material polyamide resin (A), the produced polyamide resin (B) can also have good yellowness.

[Production Method of Polyamide Resin (A)]
The polyamide resin (A) as a raw material in the present invention is obtained by polycondensation reaction between a diamine component corresponding to the diamine unit and a dicarboxylic acid component corresponding to the dicarboxylic unit.
The polycondensation reaction is performed by, for example, a melt polycondensation method. Examples of the melt polycondensation method include a method in which a diamine component is directly added to a molten dicarboxylic acid component and polycondensed. In this case, in order to keep the reaction system in a uniform liquid state, the diamine component is continuously added to the dicarboxylic acid component, while the reaction temperature is not lowered below the melting point of the generated polyamide oligomer and / or polyamide resin. The polycondensation proceeds while the system is heated. Moreover, you may pressurize a reaction system while dripping a diamine component.
Moreover, the method of heating the nylon salt which consists of a dicarboxylic acid component and a diamine component under pressure in presence of water, and performing a polycondensation reaction is mentioned. At this time, the reaction may be performed while dehydrating the condensed water as necessary.
The polyamide resin produced by the above method can be used as the raw material polyamide resin (A) 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 a heating device used in solid phase polymerization, a continuous heating drying device, a tumble dryer, a conical dryer, a rotary drum heating device called a rotary dryer, etc., and a rotary blade inside a nauta mixer are provided. A conical heating device can be preferably used, but a known method and device can be used without being limited thereto.
Further, the polyamide resin (A) may be appropriately dried after the polycondensation reaction and adjusted so as to have the above moisture content.

[Phosphorus atom-containing compound, alkali metal compound]
The polyamide resin (A) used as a raw material in the present invention is preferably obtained by polycondensation of a dicarboxylic acid component and a diamine component in the presence of a phosphorus atom-containing compound. Thus, when a phosphorus atom containing compound is mix | blended before manufacture of a polyamide resin (A), while making polyamide resin (A) and a polyamide resin (B) favorable, the polymerizability at the time of manufacturing a polyamide resin ( Coloring of A) and the polyamide resin (B) can be prevented.
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 phosphonate, potassium phosphonite, magnesium phosphonite, calcium phosphonite, phenyl phosphonite, sodium phenyl phosphonite, potassium phenyl phosphonite, lithium phenyl phosphonite, ethyl phenyl phosphonite, 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, hypophosphorous acid metal salts such as sodium hypophosphite, calcium hypophosphite, potassium hypophosphite, lithium hypophosphite, etc. are particularly effective in promoting the polycondensation reaction, and also in preventing coloration. Since it is excellent, it is preferably used, and sodium hypophosphite is particularly preferable. In addition, the phosphorus atom containing compound which can be used by this invention is not limited to these compounds.

  It is preferable that the compounding quantity of a phosphorus atom containing compound is 10-500 ppm in conversion of the phosphorus atom density | concentration in a polyamide resin (A), More preferably, it is 20-300 ppm. If it is 10 ppm or more, the polycondensation reaction proceeds at an appropriate rate, and coloring is unlikely to occur during the polycondensation reaction. If it is 500 ppm or less, the polyamide resin is hardly gelled, and the mixing of fish eyes considered to be caused by the phosphorus atom-containing compound can be reduced, and the appearance of the molded product becomes good.

The polyamide resin (A) as a raw material may be obtained by polycondensation in the presence of an alkali metal compound in addition to the phosphorus atom-containing compound.
In order to prevent the coloring of the polyamide resin (A) and the polyamide resin (B), a sufficient amount of the phosphorus atom-containing compound needs to be present. There is a risk of causing gelation. Therefore, by blending an alkali metal compound in addition to the phosphorus atom-containing compound, the amidation reaction rate can be adjusted and gelation can be prevented.
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 (molar ratio) between the phosphorus atom-containing compound and the alkali metal compound in the polyamide resin (A) is such that the phosphorus atom-containing compound / alkali metal compound = 1. The range of 0 / 0.05 to 1.0 / 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 (B)>
The polyamide resin (B) produced in the present invention has the same diamine unit and dicarboxylic acid unit as the polyamide resin (A) which is the raw material of the present invention. Moreover, similarly to the polyamide resin (A), units other than the diamine unit and the dicarboxylic acid unit may optionally be included.

[Molecular weight of polyamide resin (B)]
As an index representing the molecular weight of the polyamide resin, there is a relative viscosity. According to the production method described later of the present invention, the polyamide resin (B) can be appropriately polymerized, and the relative viscosity thereof can be sufficiently increased. The relative viscosity of the polyamide resin obtained by the production method of the present invention is preferably 2.5 to 4.0, more preferably 2.7 to 3.5.

[Dispersion degree of polyamide resin (B)]
An index indicating the degree of dispersion of the polyamide resin is Mw / Mn. In the polyamide resin (B) obtained in the present invention, it is difficult to produce an oligomer component having a molecular weight of 1000 or less, and the degree of dispersion is relatively low. Specifically, Mw / Mn is preferably 2.0 to 4.5, and more preferably 2.5 to 4.0. In addition, Mw (weight average molecular weight) and Mn (number average molecular weight) are calculated | required as a value of standard polymethylmethacrylate conversion by gel permeation chromatography (GPC).

[Moisture content of polyamide resin (B)]
As will be described later, the polyamide resin (B) obtained in the present invention is sufficiently dehydrated and has a low moisture content. Specifically, the moisture content is preferably 0.3% or less, more preferably 0.1% or less. Moreover, in order to manufacture a polyamide resin efficiently, a moisture content will be 0.01% or more, for example. The moisture content mentioned here is a value measured in the case of cooling by air cooling (air cooling type).
In addition, although the cooling method of the strand-shaped resin obtained by extruding from the extruder mentioned later includes an air cooling type and a water cooling type cooling with a water bath, it is not limited to these. In the case of the water cooling type, it is possible to rapidly cool, but a drying step may be required. In the case of the air cooling type, the drying process can be omitted, but a cooling distance is required.

[Yellowness of polyamide resin (B)]
The polyamide resin (B) obtained in the present invention has little heat history due to heating, and can suppress the yellowness to a low value. Specifically, the yellowness is preferably 30 or less, and more preferably 25 or less.

[Melting point of polyamide resin (B)]
In the present invention, even a polyamide resin having a high melting point can be produced by the production method described later. The melting point of the polyamide resin (B) is, for example, 220 ° C. or higher. However, in the present invention, a polyamide resin having a melting point of 300 ° C. or higher can be produced. The melting point of the polyamide resin is usually 380 ° C. or lower, preferably 360 ° C. or lower. In the present specification, the melting point refers to the temperature of the peak on the high temperature side unless otherwise specified when the polyamide resin has two melting point peaks.

  The polyamide resin (B) of the present invention is, for example, a packaging container that stores and stores various products such as various liquid beverages, various liquid foods, liquid pharmaceuticals, liquid daily necessities; various food products, various pharmaceuticals, various daily commodities, Packaging materials for packaging various products such as various electronic materials; industrial materials such as fiber and CFRP; fuel tanks for automobiles, fuel tubes, connectors, sliding parts, radiator tanks, engine mounts, connector parts, etc. and liquid crystal displays Can be molded into articles such as industrial backlight parts, semiconductor substrate parts, casings for mobile phones and personal computers, and metal parts.

<Method for producing polyamide resin (B)>
In the present invention, the polyamide resin (A) is further polycondensed using an extruder to obtain a polymerized polyamide resin (B). Here, being polymerized means that the relative viscosity of the polyamide resin (B) is higher than the relative viscosity of the starting polyamide resin (A).
The extruder used in the present invention is an extruder composed of a co-rotating meshing twin screw and has at least one or more vacuum vents. Further, the extruder has a pressure-decreasing element that increases the filling rate of the polyamide resin in a portion closer to the supply unit than the position where the vacuum vent is provided, and the range of 30 to 70% of the total screw length is 300 torr or less. It is intended to be a vacuum region. Hereinafter, the manufacturing method of the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a schematic view showing an example of an extruder used in the present invention.
The extruder used in the present invention includes a supply unit A having a supply port such as a hopper at the most upstream position, and a plurality of kneading units B1 disposed downstream of the supply unit A for kneading or mixing the resin. -B3 and the die D arranged at the most downstream position. Further, the extruder has conveying units E1 to E4 for conveying the resin between the supply unit A and the kneading unit B1, between the kneading units B1 to B3, and between the kneading unit B3 and the die D. . In addition, in the example of FIG. 1, although three kneading | mixing parts B1-B3 are shown, it is not necessarily limited to this, Any number may be sufficient if it is one or more.
However, it is preferable that one or more kneading parts are present on the upstream side of the vacuum area VA described later, and there may be two or more kneading parts. Moreover, it is preferable that the vacuum area VA also has one or more kneading parts.

  In general, an extruder composed of a co-rotating engagement type twin screw is an extruder having two types of screws rotating in the same direction in a cylinder and having an engagement ratio of 1.2 to 1.7 and having a self-cleaning property. Machine.

In the present invention, the polyamide resin (A) as a raw material is supplied from the supply unit A, and the raw material supplied from the supply unit A is heated and die through the conveying units E1 to E4 and the kneading units B1 to B3. To D. Here, the polyamide resin (A) is heated and melted in the conveying parts E1 to E4 and the kneading parts B1 to B3, and is polycondensed by being kneaded in the kneading parts B1 to B3, thereby increasing the degree of polymerization. And extruded from the die E as a polyamide resin (B).
Although it does not specifically limit in this invention, The polyamide resin (A) used as a raw material is supplied from the supply part A in a powder form, a particle form, or a pellet form.

In order to allow the polyamide resin to be melted, kneaded, and properly extruded, at least a part of the interior of the extruder is set to a temperature higher than the melting point of the polyamide resin (B) to be manufactured, and the die D The resin temperature extruded from is made higher than the melting point of the polyamide resin (B).
The internal temperature of the extruder may all be set constant, but may have a relatively low temperature region and a relatively high temperature region. For example, if it is necessary to quickly soften the polyamide resin on the upstream side and fill the screw, the temperature on the upstream side should be set slightly higher, the temperature on the intermediate part should be lower, and the downstream side should be set higher than the upstream side. Also good. Furthermore, when it is necessary to prevent heat degradation of the polyamide as much as possible, the resin pressure is stabilized by lowering the temperature on the downstream side to near the softening temperature at which there is no problem with the polyamide, so that the strand can be pulled out. May be stabilized.

The site | part corresponding to each kneading | mixing part B1-B3 consists of the kneading | mixing element X and the pressure | voltage fall element Y in the downstream of the kneading element X in the said screw. As will be described later, the kneading element X is appropriately selected from a kneading disk, a rotor, a mixing element (mixing screw), a mixing gear, or the like. However, the kneading element X may be a single kneading element X by combining two or more of these elements.
The pressure-lowering element Y has a pressure-lowering ability and increases the resin filling rate in the kneading element X in each of the kneading parts B1 to B3. Examples thereof include a reverse screw type full flight and a sealing disk. In each kneading part, the pressure-lowering element Y increases the filling rate of the resin corresponding to the kneading element X, so that the kneading element X can appropriately mix and disperse the resin. Moreover, the pressure | voltage fall element Y can be made into a vacuum area | region by making the area | region downstream from the pressure | voltage fall element Y into a negative pressure with the vacuum vent in the downstream, as mentioned later.
Moreover, the site | part corresponding to the conveyance parts E1-E4 in the said screw consists of feed screws, such as a full flight screw element, for example. The screw shape may be a single thread, a double thread, or a triple thread, but the double thread is the most versatile.

Further, the extruder includes an open vent OV1 and vacuum vents VV1 and VV2. In the present invention, the open vent OV1 is disposed on the upstream side (supply part A side), and the vacuum vents VV1 and VV2 are disposed on the downstream side (die D side).
More specifically, the vacuum vent VV1 is disposed in the transport unit E3 between the kneading units B2 and B3, and the vacuum vent VV2 is disposed in the transport unit E4 between the kneading unit B3 and the die D. Then, the area downstream of the step-down element Y of the kneading part B2 and from the conveying part E3 to the end part on the die D side is defined as a vacuum area VA by the vacuum vents VV1 and VV2. Note that the number and arrangement position of the vacuum vents in FIG. 1 are merely examples, and the present invention is not limited to this. The number and arrangement positions may be such that the vacuum area VA can have a predetermined length and a predetermined degree of vacuum. Good.
Further, in order to ensure a sufficient degree of vacuum in the downstream region and further increase the molecular weight of the polyamide resin, at least one vacuum vent is 25% or less of the total screw length from the end of the die D side of the extruder. It is preferable to be provided within the range.

Further, in FIG. 1, the open vent OV1 is provided in the transport unit E2 between the kneading units B1 and B2, but is located on the supply unit A side from the vacuum region VA and is disposed on the most supply unit A side. If it arrange | positions in the downstream position rather than the kneading part B1, the arrangement position and number will not be specifically limited, Two or more open vents may be provided.
Moreover, in this invention, the open vent OV may be abbreviate | omitted and all the vents provided in an extruder may be a vacuum vent. In the example of FIG. 1 as well, the open vent OV1 may be a vacuum vent, so that the vacuum region extends from the downstream of the kneading part B1 to the end on the die D side, and the vacuum region can be enlarged.
In the present invention, the polyamide resin (A) as a raw material has a relatively high molecular weight, and the polycondensation reaction proceeds slowly even in the upstream portion of the extruder, so that not much water is generated. Therefore, even if an oven vent is not provided on the upstream side, there is little dehydration or dehydrated water vapor does not flow back to the supply unit side. However, when the moisture content of the raw material polyamide resin (A) is relatively high, by providing an oven vent, water vapor is extracted from the open vent, and insufficient dehydration, reverse flow of water vapor, and the like are prevented.

In the present invention, the polyamide resin is preferably completely melted at least when it reaches the vacuum region VA. Therefore, for example, when the polyamide resin (A) is supplied in powder form from the supply unit A, no powdered resin exists in the vacuum region VA.
As described above, the polyamide resin is melted before reaching the vacuum region VA, so that the solid polyamide resin is not sucked by the vacuum vents VV1 and VV2 to cause clogging of the vacuum vents VV1 and VV2. .

  In the present invention, the vacuum region VA is in the range of 30 to 70% of the total screw length. When the range of the vacuum area VA is less than 30%, the area under the negative pressure is reduced, resulting in a problem that the polycondensation reaction does not sufficiently proceed. On the other hand, if it exceeds 70%, the polyamide resin is transported to the vacuum region VA without being melted, so that the unmelted resin adheres to the vacuum vent and the vacuum vent is closed. From these viewpoints, the range of the vacuum region VA is preferably 40 to 70%.

In the present invention, the degree of vacuum in the vacuum region VA is kept at 300 torr or less. When the degree of vacuum in the vacuum region VA is greater than 300 torr, the polyamide resin is not sufficiently dehydrated, and the moisture content of the obtained polyamide resin may not be sufficiently reduced. In addition, the polycondensation reaction of the polyamide resin cannot proceed appropriately, and the molecular weight may not be sufficiently increased. Further, the yellowness (YI) of the polyamide resin may be increased.
The degree of vacuum in the vacuum region VA is preferably 150 torr or less, more preferably 80 torr or less, and most preferably 50 torr or less. By setting the degree of vacuum below this upper limit, the moisture content of the polyamide resin is lowered and the polycondensation reaction is further facilitated.
The lower limit of the degree of vacuum is not particularly limited, but is usually 1 torr or more depending on the characteristics of the apparatus.
In the present invention, the region upstream of the vacuum region VA in the extruder is a region where the pressure is higher than 300 torr, but is usually a normal pressure region that is not substantially negative pressure. In this region, an inert gas such as nitrogen is usually supplied from the supply unit A.

  In the present invention, the degree of vacuum is measured at each vacuum vent. For example, in the example of FIG. 1, the vacuum vent VV1 uses the supply unit E3 and the kneading unit B3 as negative pressure, and the degree of vacuum measured by the vacuum vent VV1 is the vacuum of the supply unit E3 and the kneading unit B3. Degrees. Similarly, the vacuum vent VV2 has a negative pressure inside the supply unit E4 and the die D, and the degree of vacuum measured by the vacuum vent VV2 is the degree of vacuum inside the supply unit E4 and the die D.

  In general, substance mixing is divided into dispersive mixing and distributed mixing. Dispersive mixing refers to mixing with particle size reduction, i.e., particle fragmentation, and distributed mixing refers to mixing by position exchange between particles. Also in the present invention, strong dispersion mixing means mixing in which the mixing mode involving crushing of the polyamide resin is dominant, and strong distribution mixing property means mixing in the position exchange of the polyamide resin is dominant. By mixing is not meant that dispersive mixing does not occur when dispersive mixing occurs or dispersive mixing does not occur when distributive mixing occurs.

  Among the kneading elements listed above, elements having strong dispersion and mixing include kneading disks having a wide disk width (see FIG. 2), rotors (see FIG. 3), etc., but are not limited thereto. Absent. The kneading disk is a combination of a plurality of disks, and the kneading disk having a wide disk width has a ratio W / D of the disk width W to the screw diameter D of 0.15 or more. 5 or less.

  Further, as an element having a strong distribution and mixing property, a kneading disk having a narrow disk width in which the ratio W / D of the disk width W to the screw diameter D is 0.02 or more and less than 0.15, the rotor shown in FIG. The mixing element shown in FIG. 4 and the mixing gear shown in FIG. 5 can be mentioned, but the invention is not limited to these. The mixing element shown in FIG. 4 is an SME mixing element provided with a notch in a full-flight disk with a positive thread, but the mixing element is a ZME provided with a notch in a full-flight disk with a reverse thread shown in FIG. It may be a mixing element. Further, the mixing gear may or may not have a self-cleaning property.

  In addition, the rotor has a feature that it can apply a uniform shear stress to the material although the maximum shear stress applied to the material is small compared to the kneading disk. Therefore, as described above, both the distribution mixing property and the dispersion mixing property are relatively strong. In addition, even if the rotor is a continuous type formed so that the cross section is smoothly continuous as shown in FIG. 3A, the cross section is formed discontinuously as shown in FIG. 3B. It may be a discontinuous type.

In the present invention, the element having strong dispersion and mixing constitutes the upstream kneading section (B1 and B2 in FIG. 1), and the element having strong distribution and mixing constitutes the downstream kneading section (B3 in FIG. 1). It is preferable to do.
As described above, in the present invention, by using the kneading element X on the upstream side as a screw having a strong dispersion and mixing property, the shearing force is increased, and complete melting by shearing heat generation is achieved. Thus, a uniform mixed state can be obtained at a relatively upstream position.
There may be one kneading part composed of elements on the upstream side with strong dispersion and mixing properties, but it is preferable that there are two or more kneading parts. Furthermore, it is preferable that one or more kneading parts composed of elements having a strong dispersion and mixing property are present at a position upstream of the vacuum region VA.
Here, it is more preferable that the highly dispersible element constituting the upstream kneading part is a kneading disk having a wide disk width. Further, the kneading disk has a ratio W / D of preferably 0.2 or more, and more preferably 0.3 or more. Thus, by increasing the ratio W / D, it is possible to further increase the dispersibility.

In addition, it is more preferable that one or more kneading parts composed of elements having a strong distribution and mixing property be provided within a range of 25% or less of the total screw length from the end on the die D side of the extruder, The kneading part is usually in the vacuum region VA, for example, the kneading part B3 in the example of FIG.
In the present invention, since the element having strong distribution mixing property is provided on the downstream side, the balance between dispersion mixing and distribution mixing is improved. For example, it is possible to prevent excessive heat generation by applying an excessive shear force to the polyamide resin, thereby suppressing an increase in YI and the like. Further, gelation and the like can be prevented, and a decrease in molecular weight can also be prevented. Moreover, it is preferable that the element with a strong distribution mixing property which comprises the downstream kneading part is a mixing element.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
In the following examples,
Poly 1,3-bisaminomethylcyclohexane adipamide is designated as “N-1,3-BAC6”,
Poly 1,4-bisaminomethylcyclohexane adipamide is designated as “N-1,4-BAC6”,
Poly 1,4-bisaminomethylcyclohexane sebacamide as “N-1,4-BAC10”,
Polymetaxylylene adipamide "N-MXD6",
Polyparaxylylene sebacamide "N-PXD10"
Poly 1,9-nonanediamine terephthalamide as “N-9T”,
Poly 1,3-bisaminomethylcyclohexane terephthalamide is "N-1,3-BACT"
Poly 1,10-decanediamine terephthalamide is referred to as “N-10T”.

In the present invention, relative viscosity, moisture content, yellowness, glass transition temperature, melting point, molecular weight and molecular weight distribution were measured by the following methods.
(1) Relative viscosity 0.2 g of polyamide resin 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. The relative viscosity was calculated from t and t _{0 according} to the following formula.
Relative viscosity = t / t ₀
(2) Moisture content Using a trace moisture measuring device AQ-2000 manufactured by Hiranuma Sangyo Co., Ltd., measurement was performed under conditions of 230 ° C. and 30 minutes in a nitrogen atmosphere.
(3) Yellowness (YI)
It measured by the permeation | transmission method according to ASTMD1003 using the Nippon Denshoku Industries Co., Ltd. Z-Σ80 color difference meter.
(4) Glass transition temperature and melting point DSC measurement (differential scanning calorimetry) using a differential scanning calorimeter (manufactured by Shimadzu Corporation, trade name: DSC-60) under a nitrogen stream at a heating rate of 10 ° C / min. The glass transition temperature (Tg) and the melting point (Tm) were determined.

  In the examples and comparative examples, the polyamide resin (A) as a raw material was produced by the methods of Production Examples 1 to 7 below.

Production Example 1 (Production of polyamide 1)
9000 g of adipic acid (manufactured by Asahi Kasei Chemicals Co., Ltd.) precisely weighed in a reaction vessel having an internal volume of 50 liters equipped with a stirrer, a partial condenser, a total condenser, a thermometer, a dropping tank and a nitrogen introduction tube, and a strand die 61.58 mol), 7.75 g (0.07 mol) of sodium hypophosphite, 5.40 g (0.07 mol) of sodium acetate, and after sufficient nitrogen substitution, the system was stirred under a small amount of nitrogen stream. While heating to 170 ° C. To this, 8357.8 g (61.58 mol) of metaxylylenediamine (manufactured by Mitsubishi Gas Chemical Co., Inc.) was added dropwise with stirring, and the inside of the system was continuously heated while removing the condensed water produced. After completion of the addition of metaxylylenediamine, the reaction was continued at an internal temperature of 260 ° C. for 40 minutes, and then the inside of the system was pressurized with nitrogen, the polymer was taken out of the strand die and pelletized, and about 15 kg of N-MXD6 (Polyamide 1) was obtained. The concentration of the phosphorus atom-containing compound in polyamide 1 was 150 ppm in terms of phosphorus atom concentration.

Production Example 2 (Production of polyamide 2)
Sebacic acid (made by Ito Oil Co., Ltd.) as the dicarboxylic acid component, paraxylylenediamine (made by Showa Denko) as the diamine component, calcium hypophosphite instead of sodium hypophosphite, calcium hypophosphite N-PXD10 was obtained in the same manner as in Production Example 1 except that 0.045 mol, sodium acetate was 0.06 mol, and the internal temperature after completion of the diamine addition was 300 ° C. (Polyamide 2). The concentration of the phosphorus atom-containing compound in polyamide 2 was 150 ppm in terms of phosphorus atom concentration.

Production Example 3 (Production of polyamide 3)
N-1,3-BAC6 was obtained in the same manner as in Production Example 1 except that 1,3-bisaminomethylcyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd.) having a cis ratio of 70 mol% was used as the diamine component. Polyamide 3). The concentration of the phosphorus atom-containing compound in polyamide 3 was 146 ppm in terms of phosphorus atom concentration.

Production Example 4 (Production of polyamide 4)
Adipic acid is used as the dicarboxylic acid component, 1,4-bisaminomethylcyclohexane (produced by Guangei Chemical Industry Co., Ltd.) with a trans ratio of 62 mol% is used as the diamine component, and calcium hypophosphite is used instead of sodium hypophosphite N-1,4-BAC6 was obtained in the same manner as in Production Example 1 except that calcium hypophosphite was 0.065 mol, sodium acetate was 0.044 mol, and the internal temperature after completion of the diamine addition was 300 ° C. (Polyamide 4). The concentration of the phosphorus atom-containing compound in polyamide 4 was 260 ppm in terms of phosphorus atom concentration.

Production Example 5 (Production of polyamide 5)
10060 terephthalic acid precisely weighed in a pressure-resistant reaction vessel with an internal volume of 50 L equipped with a stirrer, a partial condenser, a full condenser, a pressure regulator, a thermometer, a dripping tank and a pump, an aspirator, a nitrogen introduction pipe and a bottom exhaust valve 0.09 g (60.56 mol), 1,9-nonanediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 9765.4 g (61.58 mol), benzoic acid 250.7 g (2.05 mol), calcium hypophosphite 7.31 g (0.35 mol). 043 mol), 4.70 g (0.057 mol) of sodium acetate and 6.9 liters of distilled water were added, and after sufficiently purging with nitrogen, the reaction vessel was sealed and heated to 210 ° C. with stirring. The internal pressure at this time was 2.2 MPa. The reaction was continued for 1 hour, and then the temperature was raised to 230 ° C., this temperature was maintained for 2 hours, and the reaction was carried out while gradually removing water vapor and maintaining the pressure at 2.2 MPa. Next, the pressure was reduced to 1.0 MPa over 30 minutes, and the reaction was further continued for 1 hour to obtain a prepolymer. Next, this prepolymer was dried at 100 ° C. under reduced pressure for 12 hours, pulverized to a size of 2 mm or less, 25 mmφ, L / D = 25, 2-vent twin screw extruder (Toyo Seiki Seisakusho Lab.) Melt polymerization was performed using Plastmill 2D25W). The cylinder temperature of the extruder was set to 330 ° C., and the resin temperature was adjusted to 325 to 330 ° C. The hopper was sealed by always flowing dry nitrogen. Moreover, the 1st vent was open | released and the 2nd vent maintained the pressure reduction degree of 50 mmHg using the vacuum pump. The screw rotation speed was set to 40 rpm, the prepolymer supply amount from the hopper was 1 kg / hour, and N-9T was obtained (polyamide 5). The concentration of the phosphorus atom-containing compound in polyamide 5 was 150 ppm in terms of phosphorus atom concentration.

Production Example 6 (Production of polyamide 6)
8759.6 g (61.58 mol) of 1,3-bisaminomethylcyclohexane (Mitsubishi Gas Chemical Co., Ltd.) having a cis ratio of 70 mol% as the diamine component, and 10230.3 g (61.58 mol) of terephthalic acid as the mono / dicarboxylic acid component Except for the above, N-1,3-BACT was obtained in the same manner as in Production Example 5 (polyamide 6). The concentration of the phosphorus atom-containing compound in polyamide 6 was 159 ppm in terms of phosphorus atom concentration.

Production Example 7 (Production of polyamide 7)
N-10T was obtained in the same manner as in Production Example 5 except that the diamine was 1,10-decanediamine (polyamide 7). The concentration of phosphorus atom-containing compound in polyamide 7 was 142 ppm in terms of phosphorus atom concentration.

Table 1 shows the measurement results of the relative viscosity, moisture content, and yellowness of polyamides 1-8.

  Next, in Examples 1 to 7 and Comparative Examples 1 and 2, the polyamide resins 1 to 7 were polycondensed by melt kneading using an extruder to obtain a polyamide resin (B). In each of the examples and comparative examples, TEM 26DS manufactured by Toshiba Machine Co., Ltd., in which a plurality of barrels are assembled to form one extruder, was used. This extruder is composed of a co-rotating mesh type twin screw, L / D (L: screw length, D: screw diameter) is 64.6, and the cylinder major axis φ when the cylinder is viewed from the front is It was 26 mm.

Example 1
As shown in FIG. 7, the extruder is formed by connecting 16 barrels (including the die D) to a barrel provided with a hopper and provided with a supply unit A, and among those barrels, One open vent OV1 is provided in the sixth barrel from the supply section A side, and vacuum vents VV1, VV2, and VV3 are provided in the 11, 13, and 14th barrels, respectively. The second, fifth, seventh, and ninth barrels were each provided with a kneading disk element on the screw, and a reverse screw type full flight was connected downstream thereof to form kneading parts B1 to B4. The twelfth barrel was provided with a mixing element on its screw and connected with a reverse screw type full flight downstream thereof to form a kneading part B5. Thereby, the barrels 10 to 16 became the vacuum region VA, and the length thereof was 43.8% of the total screw length. The screw in the barrels other than the kneading parts B1 to B5 is a double-threaded flight screw element and constituted a conveying part.

Under the following extrusion conditions, the polyamide 1 was charged from the hopper of the supply unit A using a feeder, and further, dry nitrogen was constantly flowed from the hopper to carry out the reactive extrusion to obtain a polyamide resin (B). The resin outlet temperature was 265 ° C. The extrusion conditions were as follows.
<Extrusion conditions>
Feeder amount: 10 kg / h
Screw rotation speed: 100rpmh
Set temperature (° C.): C1 / C2 to C8 / C9 to C15 / C16
= 260/260/260/260
Vacuum degree of vacuum vent: 30 torr
* Each of C1 to C16 indicates a set temperature in each of the first to sixteenth barrels.

Example 2
A polyamide resin 2 was obtained in the same manner as in Example 1 except that polyamide 2 was used and reactive extrusion was performed under the following extrusion conditions. The resin outlet temperature was 318 ° C.
<Extrusion conditions>
Feeder amount: 10 kg / h
Screw rotation speed: 100rpm
Set temperature (° C.): C1 / C2 to C8 / C9 to C15 / C16
= 300/300/300/300
Vacuum degree of vacuum vent: 30 torr

Example 3
As shown in FIG. 8, in the extruder, vacuum vents VV1, VV2, and VV3 were provided in each of the sixth, eleventh, and fourteenth barrels, and no oven vent was provided. In addition, an element of a kneading disk was provided in each of the fifth, seventh, and ninth barrel screws, and a reverse screw type full flight was connected downstream thereof to form kneading parts B1 to B3. Further, a mixing element was provided on the screw of the twelfth barrel, and a reverse screw type full flight was connected downstream thereof to obtain a kneading part B4. In this extruder, the barrels 6 to 16 became the vacuum region VA, and the length thereof was 68.8% of the total screw length. The other configuration of the extruder was the same as in Example 1.
Under the following extrusion conditions, polyamide 3 was charged from the hopper of supply section A using a feeder, and further, dry nitrogen was constantly flowed from the hopper to carry out reactive extrusion to obtain a polyamide resin (B). The resin outlet temperature was 267 ° C.
<Extrusion conditions>
Feeder amount: 10 kg / h
Screw rotation speed: 200rpm
Set temperature (° C.): C1 / C2 to C8 / C9 to C15 / C16
= 260/260/260/260
Vacuum degree of vacuum vent: 30 torr

Example 4
A polyamide resin (B) was obtained in the same manner as in Example 3 except that polyamide 4 was used and reactive extrusion was performed under the following extrusion conditions. The resin outlet temperature was 319 ° C.
<Extrusion conditions>
Feeder amount: 10 kg / h
Screw rotation speed: 200rpm
Set temperature (° C.): C1 / C2 to C8 / C9 to C15 / C16
= 300/310/290/310
Vacuum degree of vacuum vent: 30 torr

Example 5
A polyamide resin (B) was obtained in the same manner as in Example 3 except that polyamide 5 was used and reactive extrusion was performed under the following extrusion conditions. The resin outlet temperature was 359 ° C.
<Extrusion conditions>
Feeder amount: 20 kg / h
Screw rotation speed: 200rpm
Set temperature (° C.): C1 / C2 to C8 / C9 to C15 / C16
= 350/350/350/350
Vacuum degree of vacuum vent: 30 torr

Example 6
A polyamide resin (B) was obtained in the same manner as in Example 3 except that polyamide 6 was used and reactive extrusion was performed under the following extrusion conditions. The resin outlet temperature was 319 ° C.
<Extrusion conditions>
Feeder amount: 10 kg / h
Screw rotation speed: 200rpm
Set temperature (° C.): C1 / C2 to C8 / C9 to C15 / C16
= 300/310/290/310
Vacuum degree of vacuum vent: 30 torr

Example 7
A polyamide resin (B) was obtained in the same manner as in Example 3 except that polyamide 7 was used and reactive extrusion was performed under the following extrusion conditions. The resin outlet temperature was 313 ° C.
<Extrusion conditions>
Feeder amount: 20 kg / h
Screw rotation speed: 200rpm
Set temperature (° C.): C1 / C2 to C8 / C9 to C15 / C16
= 300/310/290/310
Vacuum degree of vacuum vent: 30 torr

Comparative Example 1
As shown in FIG. 9, in the extruder, two vacuum vents were provided in the 13th and 14th barrels, and no oven vent was provided. The kneading disc elements B1 to B4 were prepared by providing kneading disk elements on the screws at the second, fifth, seventh and ninth barrel positions, and connecting reverse screw type full flights downstream of these elements. Further, a mixing element was provided on the screw at the 12th barrel position, and a reverse screw type full flight was connected to the downstream thereof to obtain a kneading part B5. In this extruder, the barrel 13 to the barrel 16 became the vacuum region VA, and the length thereof was 25% of the total screw length. The other configuration was the same as that of the extruder.
Under the following extrusion conditions, the polyamide 2 was charged from the hopper of the supply section A using a feeder, and further, dry nitrogen was constantly flowed from the hopper to carry out the reactive extrusion to obtain a polyamide resin (B). The resin outlet temperature was 309 ° C.
<Extrusion conditions>
Feeder amount: 20 kg / h
Screw rotation speed: 200rpm
Set temperature (° C.): C1 / C2 to C8 / C9 to C15 / C16
= 300/300/280/300
Vacuum degree of vacuum vent: 90 torr

Comparative Example 2
As shown in FIG. 10, in the extruder, vacuum vents VV1, VV2, and VV3 were provided in the third, eleventh, and fourteenth barrels, respectively. Also, kneading parts B1 to B4 are provided by providing kneading disk elements on the screws at the second, fifth, seventh, and ninth barrel positions, and connecting reverse screw type full flights downstream of these elements. . A mixing screw was provided in the 12th barrel position screw, and a reverse screw type full flight was connected downstream thereof to obtain a kneading part B5. In this extruder, the barrels 3 to 16 were in the vacuum region VA, and the length thereof was 87.5% of the total screw length.
Under the following extrusion conditions, polyamide 1 was charged from the hopper of the supply unit A using a feeder, and further, dry nitrogen was constantly flowed from the hopper to carry out reactive extrusion. However, since the polyamide resin could not be sufficiently melted, unmelted resin adhered to the third vacuum vent VV1 provided from the hopper, and the vacuum vent VV1 was closed, so that extrusion was not possible.
<Extrusion conditions>
Feeder amount: 10 kg / h
Screw rotation speed: 200rpm
Set temperature (° C.): C1 / C2 / C3 to C15 / C16
= 260/260/260/260
Vacuum vent vacuum degree: Vent closed

  The relative viscosity, moisture content, yellowness, glass transition temperature, and melting point of the polyamide resin (B) obtained in Examples and Comparative Examples were measured. The results are shown in Table 2.

  In the methods of Examples 1 to 7, a polyamide having a sufficiently increased molecular weight and good color tone could be obtained. On the other hand, in the method of Comparative Example 1, since the vacuum region was too short, the polymerization hardly proceeded. In Comparative Example 2, the vacuum region was too long, so polyamide could not be obtained due to extrusion trouble.

A Supply part B1-B5 Kneading part D Dies E1-E4 Conveying part OV1 Oven vent VA Vacuum area VV1-VV3 Vacuum vent X Kneading element Y Step-down element

Claims (10)

An aromatic diamine unit represented by the following general formula (I-1), an alicyclic diamine unit represented by the following general formula (I-2), and an aliphatic diamine unit represented by the following general formula (I-3) A diamine unit containing 70 mol% or more of a diamine unit selected from: a linear aliphatic dicarboxylic acid unit represented by the following general formula (II-1); and an aromatic represented by the following general formula (II-2): A polyamide resin (A) containing a dicarboxylic acid unit containing 50 mol% or more of a dicarboxylic acid unit selected from dicarboxylic acid units is polycondensed to obtain a polyamide resin (B) having a higher molecular weight than the polyamide resin (A). A method for producing a polyamide resin, comprising:
In the production method, a polyamide resin (A) having a relative viscosity of 1.5 to 3.0 is used by using an extruder having at least one vacuum vent and including a co-rotating meshing twin screw. By polycondensation by melt kneading to produce a polyamide resin (B) having a higher molecular weight than the polyamide resin (A),
A method for producing a polyamide resin, wherein a pressure-lowering element is provided at a position closer to the supply unit than a position where the vacuum vent is provided, and a range of 30 to 70% of the total screw length is a vacuum region of 300 torr or less.
[[In the general formula (I-3), m represents an integer of 2 to 18.] In the general formula (II-1), n represents an integer of 2 to 18. In the general formula (II-2), Ar represents an arylene group. ]   The method for producing a polyamide resin according to claim 1, wherein the moisture content of the polyamide resin (A) is 2% by mass or less.   The method for producing a polyamide resin according to claim 1 or 2, wherein the polyamide resin (B) has a relative viscosity of 2.5 to 4.0.   The method for producing a polyamide resin according to any one of claims 1 to 3, wherein the polyamide resin (A) contains a phosphorus compound at a phosphorus atom concentration of 10 to 500 ppm.   The manufacturing method of the polyamide resin in any one of Claims 1-4 which arrange | positions an open vent in the supply part side rather than the said vacuum area | region.   The manufacturing method of the polyamide resin in any one of Claims 1-5 which provide the kneading part which knead | mixes the said polyamide resin (A) in each position on the supply part side rather than the said vacuum area | region.   The manufacturing method of the polyamide resin in any one of Claims 1-6 which provide at least 1 or more vacuum vent in the range of 25% or less of the total screw length from the die | dye side edge part of the said extruder.   The production of a polyamide resin according to any one of claims 1 to 7, wherein a kneading part having a kneading element having a strong distribution and mixing property is provided within a range of 25% or less of the total screw length from the die side end of the extruder. Method.   The polyamide according to any one of claims 1 to 8, wherein a kneading part is further provided on the supply part side of the kneading part having the kneading element having a strong distribution and mixing property, and the kneading part has a kneading element having a strong dispersion and mixing property. Manufacturing method of resin.   An article formed from the polyamide resin (B) produced by the method for producing a polyamide resin according to any one of claims 1 to 9, and selected from the group consisting of a packaging material, a packaging container, an industrial material, and an industrial part.