JP5376656B2 - Method for producing polyamide resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polyamide resin, by which the polyamide excellent in mechanical characteristics and hue after molded and excellent in processability on the production of films and fibers can be produced. <P>SOLUTION: This method for producing the polyamide resin includes a process for melt-kneading (A) a polyamide component and (B) a metal phosphite at a resin temperature of 315 to 390&deg;C and at a reduced pressure degree of &ge;0.05 MPa. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a polyamide resin.

Polyamide resins are known as engineering plastics, and are used in general-purpose consumer fields such as packaging and containers, automotive parts, electrical / electronic fields, mechanical / industrial fields, office equipment fields, and aerospace fields. Widely used as a material for
In recent years, with respect to these various parts, there has been a great demand for substitution from a metal material to a polyamide resin for the purpose of integration and weight reduction. In addition, for the purpose of reducing the weight of packaging, containers, etc., there is an increasing demand for improving film forming properties and spinnability of polyamide resins. As a result, the performance level required for polyamide resins has been further increased.

  Specifically, there is a strong demand for resin materials that have high strength that can replace metal materials, have excellent film-forming properties and spinnability, and can be used in harsh environments such as excessive heat, light, and chemicals. ing. One way to meet these demands is to increase the molecular weight of the polyamide resin.

  When increasing the molecular weight of the polyamide resin by melt polymerization, there is a problem of an increase in viscosity of the melted polyamide resin, and strong stirring is required. In this case, it is known that the polyamide resin is deteriorated by shearing heat generation by stirring, which is not preferable. As a method for increasing the molecular weight of a polyamide resin, a method of solid-phase polymerization of a polyamide resin after melt polymerization is known. In order to obtain a desired high molecular weight polyamide resin in the solid phase polymerization method, a large amount of solid phase polymerization time and heat energy are required. In addition, in order to ensure the quality of the polyamide resin such as the color tone and shorten the solid phase polymerization time, a process under a nitrogen stream or under reduced pressure is required, and the solid phase polymerization method has safety / economic problems. .

On the other hand, for the purpose of improving the performance while compensating for the shortcomings of a single polyamide resin, methods using reaction catalysts for two or more polyamides have been studied.
Patent Document 1 discloses a method of making some random copolymer by melt-kneading a homopolymer of two or more polyamides in the presence of a phosphite compound. .
In Patent Document 2, in order to form a graft and / or block copolymer, a homopolymer of one or more polyamides, polyesters, and β-unsaturated carboxylic acids is used. Specifically, a method of reacting at “atmospheric pressure or spontaneous pressure” is disclosed.
Patent Document 3 discloses a polyamide resin composition in which two or more polyamides are melt-kneaded in the presence of a phosphite compound and a metal phosphite, and a method for producing the same.

U.S. Pat. No. 4,417,032 JP 58-208324 A International Publication No. 2001/072872 Pamphlet

The techniques disclosed in Patent Documents 1 to 3 are techniques for promoting a polyamide-polyamide exchange reaction with a catalyst.
Patent Documents 1 and 2 do not describe any melt kneading under reduced pressure.
Further, Patent Document 3 specifically discloses that the pressure during melt kneading is only 0.04 or less, and the resin temperature during melt kneading is only 290 ° C. or less. is there.
Accordingly, it is difficult to obtain a high molecular weight polyamide resin by the techniques disclosed in Patent Documents 1 to 3.

 The problem to be solved by the present invention is to provide a method for producing a polyamide resin which is excellent in mechanical properties and color tone after molding, and further excellent in film forming and spinning processability.

  As a result of intensive studies to solve the above problems, the present inventors have blended a polyamide component with a metal phosphite salt as a reaction catalyst, and by a production method in which the compound is melt kneaded under different temperature conditions and reduced pressure conditions, The present inventors have found that the problems can be solved and completed the present invention.

That is, the present invention is as follows.
[1]
A process for producing a polyamide resin comprising a step of melt kneading (A) a polyamide component and (B) a metal phosphite at a resin temperature of 315 to 390 ° C. and a reduced pressure of 0.05 MPa or more.
[2]
Furthermore, (C) The manufacturing method of the polyamide resin as described in [1] which mix | blends and knead | mixes a phosphite compound.
[3]
Furthermore, (D) The manufacturing method of the polyamide resin as described in [1] or [2] which mix | blends and knead | mixes a molecular weight regulator.
[4]
With respect to 100 parts by mass of (A), 0.05 to 1 part by mass of (B), 0.05 to 1 part by mass of (C), and 0.01 to 1 of (D), if desired. The manufacturing method of the polyamide resin in any one of [1]-[3] which mix | blends a mass part.
[5]
(A) The method for producing a polyamide resin according to any one of [1] to [4], wherein the polyamide component contains at least two kinds of polyamides.

  ADVANTAGE OF THE INVENTION According to this invention, the method of manufacturing the polyamide resin which was excellent in the mechanical characteristics and color tone after shaping | molding, and also excellent in film forming and the workability at the time of spinning can be provided.

The method for producing a polyamide resin of the present embodiment includes a step of melt-kneading (A) a polyamide component and (B) a metal phosphite salt at a resin temperature of 315 to 390 ° C. and a degree of vacuum of 0.05 MPa or more. Is the method.
In the present embodiment, the (A) polyamide component can be made high molecular weight by (B) metal phosphite.
In addition, the polyamide resin obtained by the manufacturing method of the present embodiment has high strength that can be substituted for a metal material, has excellent processability such as film formation and spinning, and is in excessive heat, light, chemicals, etc. It is a high-molecular-weight polyamide resin that can be used even in severe environments and has excellent properties such as mechanical properties and color tone when formed into a molded body.

[(A) Polyamide component]
In the present embodiment, “(A) polyamide component” means a polyamide which is a polymer having an amide bond (—NHCO—) in the main chain.
Examples of the polyamide component include polycaprolactam (polyamide 6), polytetramethylene adipamide (polyamide 46), polyhexamethylene adipamide (polyamide 66), polyhexamethylene sebacamide (polyamide 610), and polyhexamethylene. Dodecamide (polyamide 612), polyundecamethylene adipamide (polyamide 116), polyundecalactam (polyamide 11), polydodecalactam (polyamide 12), polytrimethylhexamethylene terephthalamide (polyamide TMHT), polyhexamethylene Isophthalamide (polyamide 6I), polynonanemethylene terephthalamide (polyamide 9T), polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene cyclohexylamide (polyamide 6T) Amide 6C), polybis (4-aminocyclohexyl) methane dodecamide (polyamide PACM12), polybis (3-methyl-aminocyclohexyl) methane dodecamide (polyamide dimethyl PACM12), polymetaxylylene adipamide (polyamide MXD6), polyun Examples thereof include polyamides such as decamethylene hexahydroterephthalamide (polyamide 11T (H)).

As the polyamide component, one type of polyamide may be used, or two or more types of polyamide may be used in combination.
Combining two or more kinds of polyamides means that the polyamide component contains at least two kinds of polyamides. Polyamides having the same monomer (constituent unit) may be used. Different polyamides may be used.
The polyamide component containing at least two kinds of polyamides may contain at least two kinds of the above polyamides, or may be a copolyamide containing at least two kinds of the above polyamides.
By using a polyamide component containing at least two kinds of polyamides, it is possible to produce a high molecular weight polyamide resin that can be processed into a molded article having excellent color tone by utilizing a polyamide-polyamide exchange reaction.

  Among these, as a polyamide component, polycaprolactam (polyamide 6), polyhexamethylene adipamide (polyamide 66), polyhexamethylene sebamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polyhexamethylene Isophthalamide (polyamide 6I), polyhexamethylene terephthalamide (polyamide 6T), and polyhexamethylene cyclohexylamide (polyamide 6C) are preferable, and at least two different polyamides may be included.

In the present embodiment, “including at least two different polyamides” means that polyamides having different structural units are included as a polyamide component.
In the present embodiment, “the structural units are different” is not limited to the following embodiments. For example, as two types of polyamide components, a polyamide whose structural units are hexamethylenediamine and adipic acid. 66 and polyamide 6I whose structural units are hexamethylenediamine and isophthalic acid.
In this case, since polyamide 66 and polyamide 6I have different structural units of dicarboxylic acid from adipic acid and isophthalic acid, polyamide 66 and polyamide 6I are polyamides having different structural units.
A copolymer polyamide such as polyamide 66 / 6I whose structural units are hexamethylenediamine and adipic acid and isophthalic acid is also a polyamide having different structural units.

  When the polyamide component includes at least two different polyamides, the polyamide component is preferably a combination of two or more selected from the group consisting of polyamide 6, polyamide 66, polyamide 6I, and polyamide 6C.

[(B) metal phosphite]
In the present embodiment, (B) metal phosphite is phosphorous acid or hypophosphorous acid, 1, 2, 3, 4, 5, 6, 7, 8, 11, in the periodic table of elements. It means a metal salt with a group 12 or 13 element and a metal such as tin or lead.
As the phosphite metal salt, one kind of phosphite metal salt may be used, or two or more kinds of phosphite metal salts may be used in combination.

From the standpoint that higher molecular weight of the polyamide resin can be achieved more remarkably, it is preferably a metal hypophosphite, more preferably sodium hypophosphite (NaH ₂ PO ₂ ) and calcium hypophosphite (Ca (H _2). PO ₂ ) ₂ ).
The metal phosphite salt may be a hydrate, such as sodium hypophosphite monohydrate (NaH ₂ PO ₂ .H ₂ O).

In the step of melt kneading (A) the polyamide component and (B) the metal phosphite, the content of the metal phosphite is 0.05 to 1 part by mass with respect to 100 parts by mass of the polyamide component in total. It is preferable that there is, more preferably 0.05 to 0.75 parts by mass, and still more preferably 0.05 to 0.5 parts by mass.
When the content of the metal phosphite salt is 0.05 parts by mass or more, a high molecular weight polyamide resin can be obtained, and color tone deterioration and deterioration can be prevented during melt kneading at a high temperature. When the content of the metal phosphite salt is 1 part by mass or less, a polyamide resin excellent in extrudability and moldability can be obtained.

In this embodiment, in the step of melt kneading (A) the polyamide component and (B) the metal phosphite, (C) a phosphite compound and / or (D) a molecular weight regulator is further blended and melted You may knead.
Higher molecular weight can be further promoted by further blending a phosphite compound and melt-kneading. Moreover, when at least 2 or more types of polyamide is made into a polyamide component as a raw material, a polyamide-polyamide exchange reaction can further be accelerated | stimulated.
In addition, it is preferable to further mix and melt knead the molecular weight regulator because it is possible to suppress an excessive increase in the molecular weight and to control the molecular weight of the polyamide resin to a desired molecular weight.
In addition, (D) a molecular weight adjusting agent is added to a polyamide resin obtained by melt-kneading (A) a polyamide component, (B) a metal phosphite, and (C) a phosphite compound, if desired. May be spread and melt-kneaded.

[(C) Phosphite compound]
In the present embodiment, examples of the (C) phosphite compound include compounds represented by the following general formula (1) or general formula (2).
General formula (1):
(RO) _n P (OH) _3-n
(In the formula, n represents 1, 2 or 3.)
General formula (2):
(RO) _m P (R) (OH) _2-m
(In the formula, m represents 1 or 2.)
In the general formula (1) or the general formula (2), each R independently represents an aliphatic group or an aromatic group, or a substituted aliphatic group or a substituted aromatic in which a part of the group is substituted with a substituent. Indicates a group.
In general formula (1) or general formula (2), when n or m is 2 or more, in general formula (1) or general formula (2), a plurality of (RO) groups may be the same or different. Also good.

As R, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, n-pentyl, n-hexyl, n-octyl group, Examples thereof include aliphatic groups such as 2-ethylhexyl group, decyl group, lauryl group, tridecyl group, stearyl group, and oleyl group, and aromatic groups such as phenyl group and biphenyl group.
Examples of the substituent include a hydroxy group, a methyl group, an ethyl group, a propyl group, a t-butyl group, a nonyl group, a methoxy group, and an ethoxy group.

  As the phosphite compound, the phosphite compound represented by the general formula (1) is preferably trioctyl phosphite, trilauryl phosphite, tridecyl phosphite, octyl-diphenyl phosphite, trisisodecyl. Phosphite, phenyl diisodecyl phosphite, phenyl di (tridecyl) phosphite, diphenyl isooctyl phosphite, diphenyl isodecyl phosphite, diphenyl tridecyl phosphite, triphenyl phosphite, tris (nonylphenyl) phosphite, tris (2, 4-di-t-butylphenyl) phosphite, bis [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl phosphite, bis (2,4-di-t-butylphenyl) Pentaeri Ritol-di-phosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl Phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl) phosphite, 1,1,3-tris (2-methyl-4-ditridecyl phosphite-5 -T-butyl-phenyl) butane, 4,4'-isopropylidenebis (phenyl-dialkylphosphite), tris (2,4-di-t-butylphenyl) phosphite, 2,2-methylenebis (4,6 -Di-t-butylphenyl) octyl phosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphine Ito and the like.

  As the phosphite compound, the phosphonite compound represented by the general formula (2) is preferably tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylene phosphonite, and And tetrakis (2,4-di-t-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite.

  As the phosphite compound, one kind of phosphite compound may be used, or two or more kinds of phosphite compounds may be used in combination.

In the step of melt kneading (A) the polyamide component and (B) metal phosphite, and (C) when melt kneading the phosphite compound, the content of the phosphite compound is Is preferably 0.05 to 1 part by mass, more preferably 0.05 to 0.75 part by mass, and still more preferably 0.05 to 0.5 part by mass with respect to 100 parts by mass in total. .
When the content of the phosphite compound is 0.05 parts by mass or more, a high molecular weight polyamide resin can be obtained, and color tone deterioration and deterioration can be prevented during melt kneading at a high temperature. When the content of the phosphite compound is 1 part by mass or less, a polyamide resin excellent in extrudability and moldability can be obtained.

In this embodiment, when (B) a phosphite metal salt and, if desired, (C) a phosphite compound are blended and melt-kneaded, the metal phosphite and / or the phosphite compound is a polyamide. Although included in the resin, the presence state of the metal phosphite salt and the phosphite compound in the polyamide resin after melt-kneading is not particularly limited.
As the presence state, for example, it may exist as a phosphite metal salt and a phosphite compound, or may exist as a phosphate metal salt or a phosphate ester, and these are in a mixed state. May be. Further, the metal phosphite salt and the phosphite compound may exist in a hydrolyzed state, such as phosphorous acid or phosphoric acid.

[(D) Molecular weight regulator]
In this embodiment, examples of (D) molecular weight regulator include monocarboxylic acids such as water, acetic acid and stearic acid, dicarboxylic acids such as adipic acid, isophthalic acid and terephthalic acid, monoamines such as stearylamine, and hexamethylene. Examples include diamines such as diamines, and fatty acid compounds (including fatty acids, fatty acid metal salts, and fatty acid esters) such as sodium acetate, calcium acetate, stearic acid, calcium stearate, aluminum stearate, calcium montanate, and stearyl stearate. .
As the molecular weight modifier, it is preferable to use a fatty acid compound that also has an effect as a moldability improver, and more preferably a fatty acid metal salt.
As the molecular weight regulator, one kind of molecular weight regulator may be used, or two or more kinds of molecular weight regulators may be used in combination.

In the step of melt-kneading (A) the polyamide component and (B) metal phosphite, when (D) the molecular weight modifier is melt-kneaded, the content of the molecular weight modifier is 100 masses in total of the polyamide component. Preferably it is 0.01-1 mass part with respect to a part, More preferably, it is 0.025-0.75 mass part, More preferably, it is 0.05-0.5 mass part.
If the content of the molecular weight modifier is 0.01 parts by mass or more, an excessive molecular weight increase that can achieve the object of the present embodiment can be suppressed, and if it is 1 part by mass or less, extrudability and molding. A polyamide resin having excellent processability can be obtained.

As a melt-kneading method of (A) polyamide component and (B) metal phosphite and optionally (C) phosphite compound and / or (D) molecular weight modifier, all components are kneaded simultaneously. A method of kneading a pre-kneaded mixture, for example, a method of blending a metal phosphite salt with a polyamide component pre-kneaded and melt kneading; a method of feeding each component sequentially from the middle of an extruder For example, a method in which a metal phosphite is sequentially fed to a polyamide component from the middle of an extruder; and a method in which these are combined are exemplified.
When (A) and (B) are melt-kneaded, (C) and / or (D) may be further blended and melt-kneaded. (A) and (B), (C) may optionally be Further, (D) may be further blended (spread) in a polyamide resin obtained by blending and melt-kneading, and melt-kneading.
In addition, there is a method in which one or more of phosphorous acid metal salt, phosphite compound, molecular weight modifier and the like are previously processed into a tablet (tablet) by a disk pelleter or the like, and (B) It is also possible to add one or more selected from-(D) to a tablet (tablet) after being mixed and processed.
When each component of (B)-(D) is a powder, it is a preferable method to add as a tablet on handling.

When processing a tablet, the dispersibility of a raw material can also be improved by grind | pulverizing a tablet formation raw material.
The granulation of the tablet is not particularly limited, and may be dry granulation, wet granulation to which water or polyalkylene glycol is added, and wet granulation is preferable in order to increase dispersibility during melt-kneading.

  In the production method of the polyamide resin, as long as it does not impair the purpose of the present embodiment, (E) other compounds other than (A) to (D), ordinary compounds used for polyamide resins, For example, inorganic fillers such as glass fiber, glass flake, carbon fiber, and apatite compound; antimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate, zinc stannate, zinc hydroxystannate, ammonium polyphosphate, cyanuric Flame retardants such as melamine acid, succinoguanamine, melamine polyphosphate, melamine sulfate, melamine phthalate, aromatic polyphosphate, and composite glass powder; pigments and colorants such as titanium white, carbon black, and metallic pigments; Polyalkylene glycol and its terminal modified product; low molecular weight poly Styrene; oxidized low molecular weight polyethylene; substituted benzylidene sorbitol; caprolactams; and by blending the inorganic crystal nucleating agent such as talc may be melt-kneaded.

A known apparatus can be used as an apparatus for performing melt kneading. For example, a melt kneader such as a single-screw or twin-screw extruder, a Banbury mixer, and a mixing roll is preferably used.
Among these, a multi-screw extruder equipped with a devolatilization mechanism (vent) device and side feeder equipment is preferable, and a twin-screw extruder is more preferably used.

In the melt-kneading step, it is necessary to melt-knead under reduced pressure in order to increase the molecular weight of the polyamide component, and the melt-kneading is performed at a reduced pressure of 0.05 MPa or more.
The degree of reduced pressure is preferably more than 0.05 Pa, more preferably more than 0.065 MPa, still more preferably 0.07 MPa or more, and preferably 0.1013 MPa or less.
When the degree of vacuum is 0.05 MPa or more, a high molecular weight polyamide resin capable of achieving the object of the present embodiment can be obtained.

In the present embodiment, the degree of reduced pressure refers to the difference between the pressure in the devolatilization region and the atmospheric pressure with reference to the atmospheric pressure.
In the present embodiment, the devolatilization region is a region that is connected to a decompression device in the melt-kneading device and has a degree of decompression similar to that of the decompression device, and is sealed with a device wall, a stirring device, a filling resin, and the like. It is an area.

  When the degree of decompression is increased, the viscosity may increase and extrusion may become difficult. In this embodiment, the maximum temperature of the decompression device (vacuum pump, etc.) can be increased by increasing the resin temperature, or (D) adding a molecular weight regulator. The pressure can be reduced to the limit (decompression degree: 0.1013 MPa).

The measurement position of the degree of decompression may be any position from the decompression device (such as a vacuum pump) to the melt-kneading part, but the melt-kneading part (a vent port in the case of an extruder) is preferable for controlling the molecular weight of the polyamide resin. .
The degree of decompression is adjusted by installing a valve or a valved air suction nozzle at any position from the decompression device (such as a vacuum pump) to the decompression degree measurement position, but a position close to the decompression device (such as a vacuum pump) is preferable.
A drain pot for storing drain in the vent gas can be installed between the decompression device (such as a vacuum pump) and the melt-kneading unit. When a vent pot is installed, it is preferable to attach an air suction nozzle to the vent pot.

  In this embodiment, since (A) the polyamide component is blended with (B) a metal phosphite and, if desired, (C) a phosphite compound, even if the melt kneading is higher than usual, Deterioration and color tone deterioration of the polyamide resin can be reduced, and a high molecular weight polyamide resin can be obtained even with a low residence time.

The resin temperature at the time of melt-kneading is 315 to 390 ° C, preferably 330 to 390 ° C.
If the resin temperature at the time of melt-kneading is 315 ° C. or higher, a polyamide resin excellent in workability at the time of increasing the molecular weight can be obtained.
If the resin temperature at the time of melt-kneading is 390 ° C. or less, it is possible to prevent the polyamide resin from being deteriorated and the color tone from being deteriorated.
The resin temperature at the time of melt kneading can be measured, for example, as the temperature near the tip nozzle of the extrusion section of the melt kneading apparatus, and can be controlled by setting the heater temperature of the melt kneading apparatus to 300 ° C. or higher. Even when the heater temperature is 300 ° C. or lower, the resin temperature can be controlled to a desired level by setting the screw rotation speed of the melt-kneading apparatus higher than usual.

The heater temperature of the melt-kneading apparatus is preferably 300 to 390 ° C, more preferably 310 to 360 ° C.
The screw rotation speed of the melt-kneading apparatus is preferably 200 to 750 rpm, more preferably 250 to 600 rpm.
Since the control of the resin temperature is also affected by the size of the extruder, the resin temperature can be adjusted to a desired resin temperature by appropriately combining the heater temperature and the screw rotation speed.

The average residence time during melt-kneading is preferably 10 seconds or longer, more preferably 20 seconds or longer.
If the average residence time at the time of melt kneading is 10 seconds or more, a high molecular weight polyamide resin capable of achieving the object of the present embodiment can be obtained.
The average residence time means the residence time when the residence time in the melt-kneading apparatus is constant, and means the average value of the shortest residence time and the longest residence time when the residence time is not uniform.
A resin that can be distinguished from the polyamide resin of this embodiment (hereinafter abbreviated as X), such as a colorant masterbatch that is being melt-kneaded and a different color from the polyamide resin of this embodiment, is added to the melt-kneading apparatus. The average residence time can be measured by measuring the discharge start time and the discharge end time of X and averaging the discharge start time and the discharge end time.

  In the present embodiment, the polyamide resin contains (A) a polyamide component and (B) a metal phosphite, and under a temperature condition of a resin temperature of 315 to 390 ° C., a pressure reduction condition of 0.05 MPa or more. Thus, it can be produced by melt-kneading.

In the present embodiment, the polyamide resin is produced by blending (A) a polyamide component and (B) a metal phosphite, and melt-kneading at a resin temperature of 315 to 390 ° C. and a reduced pressure of 0.05 MPa or more. .
In the present embodiment, the molecular weight of the polyamide resin is measured as a relative viscosity (ηr) of 98% sulfuric acid concentration 1% and 25 ° C. measured in accordance with JIS-K6810. From the viewpoint of moldability and mechanical properties of the obtained polyamide resin. The relative viscosity (ηr) at 25 ° C. is preferably 2.0 to 7.5, more preferably 2.5 to 7.0, still more preferably 3.0 to 6.5, and more More preferably, it is 3.1 or more.
The relative viscosity at 25 ° C. can be measured by the method described in the following examples.
According to the manufacturing method of the present embodiment, since the film has a relative viscosity at 25 ° C. within the above range, film breakage and yarn breakage can be prevented, and thus a polyamide resin excellent in film forming property and spinnability is manufactured. be able to.

In the polyamide resin of the present embodiment, from the viewpoint of the surface appearance of the obtained polyamide resin, the crystallization temperature measured according to JIS-K7121 is preferably 170 ° C to 250 ° C, more preferably 175 ° C to 240 ° C. ° C, more preferably 180 ° C to 235 ° C.
The crystallization temperature can be measured by the method described in the following examples.

In a polyamide resin not containing a filler such as an inorganic filler, the tensile strength measured according to ASTM D638 is preferably 60 MPa or more, more preferably 65 MPa or more, and still more preferably, from the viewpoint of mechanical properties of the obtained polyamide resin. Is 70 MPa or more.
In a polyamide resin reinforced by blending a filler such as an inorganic filler, the tensile strength measured according to ASTM 638 is preferably 150 MPa or more, more preferably 160 MPa or more, and further preferably 170 MPa or more.
The tensile strength can be measured by the method described in the following examples.

From the viewpoint of mechanical properties of the obtained polyamide resin, the tensile elongation measured according to ASTM 638 is preferably 2% or more, more preferably 2.75% or more, and further preferably 3% or more.
The tensile elongation can be measured by the method described in the following examples.

From the viewpoint of the surface appearance of the obtained polyamide resin, the gloss value (Gs60 °) measured according to JIS-K7150 is preferably 20 or more, more preferably 30 or more, and further preferably 40 or more.
The gloss value (Gs 60 °) can be measured by the method described in the following examples.

Since the polyamide resin obtained by the production method of the present embodiment is excellent in molding processability, a known molding method such as press molding, injection molding, gas assist injection molding, welding molding, extrusion molding, blow molding, film molding, etc. Further, it is possible to satisfactorily mold using a generally known plastic molding method such as hollow molding, multilayer molding, foam molding, and melt spinning.
As a raw material for melt-kneading the polyamide resin in the present embodiment, a rework material or a recycled material obtained by pulverizing a preform or a part of a polyamide resin can be used. The manufacturing method of the present embodiment is expected to be applied to the regeneration of various molded bodies or parts.

  The molded product obtained from the polyamide resin in the present embodiment is superior in color tone, surface appearance, heat discoloration, weather resistance, heat aging resistance, light resistance, chemical resistance, etc., compared to a molded product obtained from a conventional polyamide resin. Therefore, application to various parts such as automobile parts, electronic / electric parts, industrial machine parts, various gears, and extrusion applications is expected.

  Hereinafter, the present embodiment will be described more specifically with reference to examples and comparative examples. However, the present embodiment is not limited to only these examples. In addition, the evaluation method used for this Embodiment is as follows.

1. Characteristics of polyamide resin (1-1) Relative viscosity (ηr)
The relative viscosity was measured according to JIS-K6810. Specifically, a 1% concentration solution ((polyamide resin 1 g) / (98% sulfuric acid 100 mL)) was prepared using 98% sulfuric acid and measured under a temperature condition of 25 ° C.
In the measurement of relative viscosity, the polyamide resin is derived from the polyamide component, and does not include the residue when the polyamide resin is incinerated at a decomposition temperature or higher.

(1-2) Crystallization temperature (° C)
The crystallization temperature was measured according to JIS-K7121. The measuring apparatus used was DSC-7 type manufactured by PERKIN-ELMER. The measurement conditions were that a sample of about 8 mg was kept at 300 ° C. for 2 minutes in a nitrogen atmosphere, and then the crystallization temperature was measured from the peak temperature that appeared when the temperature was lowered to 40 ° C. at a temperature drop rate of 20 ° C./min. Furthermore, after hold | maintaining at 40 degreeC for 2 minute (s), melting | fusing point was measured from the peak temperature which appears when it heated up with the temperature increase rate of 20 degree-C / min.

2. Production and characteristics of molded product (2-1) Molding of molded product (dumbbell) A molded product was produced using an injection molding machine. A PS40E manufactured by Nissei Plastic Industry Co., Ltd. was used as an injection molding apparatus, a mold temperature was set to 80 ° C., and dumbbell-shaped molded articles were obtained from polyamide resin pellets under injection molding conditions of 17 seconds for injection and 20 seconds for cooling.
The cylinder temperature was set to about 15 to 40 ° C. higher than the melting point of the polyamide resin determined according to the above (1-2).

(2-2) Tensile strength (MPa) and tensile elongation (%)
According to ASTM D638, the tensile strength and tensile elongation of the molded product obtained in (2-1) were measured.

(2-3) Molding of molded product (flat plate) A molded product was produced using an injection molding machine. A FN3000 manufactured by Nissei Plastic Industry Co., Ltd. was used as an injection molding device, a mold temperature was set to 80 ° C., and a flat molded product was obtained from polyamide resin pellets under injection molding conditions of 15 seconds for injection and 20 seconds for cooling. The size of the obtained flat plate was 90 mm long × 60 mm wide × 3 mm thick.
The cylinder temperature was set to about 15 to 40 ° C. higher than the melting point of the polyamide resin determined according to the above (1-2).

(2-4) Gross value (Gs60 °)
Using a Horiba handy gloss meter IG320, Gs60 ° of the molded product obtained in (2-3) was measured according to JIS-K7150.

(2-5) Color tone (b value)
The b value of the molded product obtained in (2-3) was measured using a color difference meter ND-300A manufactured by Nippon Denshoku. The smaller the b value, the better the color tone.

(2-6) Film-forming property The film-forming device was used by attaching a T-die having a width of 150 mm to the tip of a KZW15TW-25MC type twin screw extruder manufactured by Technobel. The resin film that emerged from the T-die was introduced into a take-up take-up device, cooled and solidified by a cooling roll unit, and then wound into a roll shape around the take-up device unit. The thickness of the film was adjusted to 70 μm, and the film formability was evaluated in the following four stages.
◎: Continuous production of good film with stable quality such as thickness ○: Continuous production is possible, but the film quality is not stable due to uneven thickness or warping in the direction perpendicular to the take-off direction Δ: During film production, the film is torn and cannot be stably formed. ×: The resin viscosity is low and it is difficult to take up.

[Example 1]
50 parts by mass of polyamide 66 (Leona 1300 manufactured by Asahi Kasei Co., Ltd. (relative viscosity (ηr) 2.84 at 25 ° C., moisture content 0.08 mass%), hereinafter abbreviated as “PA66”), and polyamide 6 (Ube Industries) SF1022A manufactured by Co., Ltd. (relative viscosity (ηr) 3.45 at 25 ° C., moisture content 0.08% by mass), hereinafter abbreviated as “PA6”) 0.1 parts by mass of sodium acid (produced by Taihei Chemical Industry Co., Ltd.) Melt kneading was performed using a twin screw extruder (ZPER25 manufactured by COPERION). The screw rotation speed was 265 rpm, the cylinder temperature was 350 ° C., and the resin temperature near the tip nozzle was 331 ° C. The extrusion rate was 15 kg / hr and the average residence time was 40 seconds. Extrusion was performed at a reduced pressure of 0.07 MPa. The polyamide resin was discharged in a strand form from the tip nozzle, and was cooled with water and cut into pellets. The pellets were dried at 80 ° C. for 24 hours under a nitrogen atmosphere. The evaluation results are shown in Table 1.

[Example 2]
0.1 parts by mass of tris (2,4-t-di-butylphenyl) phosphite (IRGAFOS168 manufactured by Ciba Specialty Chemicals) was further blended, and the same procedure as in Example 1 was performed. The resin temperature near the tip nozzle was 335 ° C. The evaluation results are shown in Table 1.

[Example 3]
It carried out similarly to Example 2 by setting the pressure reduction degree as 0.095 MPa. The resin temperature near the tip nozzle was 337 ° C. The evaluation results are shown in Table 1.

[Example 4]
0.1 parts by mass of calcium montanate (Licomont CaV102 manufactured by Clariant) was further added, and the same procedure as in Example 3 was performed. The resin temperature near the tip nozzle was 336 ° C. The evaluation results are shown in Table 1.

[ Reference Example 5]
It carried out like Example 4 using 100 mass parts of PA66 as a polyamide component. The resin temperature near the tip nozzle was 332 ° C. The evaluation results are shown in Table 1.

[Comparative Example 1]
50 parts by mass of PA66 and 50 parts by mass of PA6 were blended, and melt-kneaded using a twin screw extruder (CORPERION: ZSK25). The screw rotation speed was 265 rpm, the cylinder temperature was 280 ° C., and the resin temperature near the tip nozzle was 291 ° C. The extrusion rate was 15 kg / hr and the average residence time was 40 seconds. Extrusion was performed at a reduced pressure of 0.095 MPa. The polymer was discharged in a strand form from the tip nozzle, and water-cooled and cut into pellets. The pellets were dried at 80 ° C. for 24 hours under a nitrogen atmosphere. The evaluation results are shown in Table 1.

[Comparative Example 2]
A cylinder temperature of 350 ° C. was used as in Comparative Example 1. The resin temperature near the tip nozzle was 341 ° C. The evaluation results are shown in Table 1.

[Comparative Example 3]
It carried out similarly to the comparative example 1 using 100 mass parts of PA66 as a polyamide component. The resin temperature near the tip nozzle was 295 ° C. The evaluation results are shown in Table 1.

[Comparative Example 4]
It carried out similarly to the comparative example 2 using 100 mass parts of PA66 as a polyamide component. The resin temperature near the tip nozzle was 345 ° C. The evaluation results are shown in Table 2.

[Example 6]
The same operation as in Example 4 was carried out at a cylinder temperature of 350 ° C. and a screw rotation speed of 550 rpm. The resin temperature near the tip nozzle was 382 ° C. The evaluation results are shown in Table 2.

[Example 7]
The same operation as in Example 4 was performed at a cylinder temperature of 310 ° C. The resin temperature near the tip nozzle was 315 ° C. The evaluation results are shown in Table 2.

[Example 8]
The same procedure as in Example 4 was performed at an extrusion rate of 30 kg / hr. The resin temperature near the tip nozzle was 342 ° C., and the average residence time was 20 seconds. The evaluation results are shown in Table 2.

[Example 9]
The same procedure as in Example 4 was carried out at an extrusion rate of 7.6 kg / hr. The resin temperature near the tip nozzle was 355 ° C., and the average residence time was 59 seconds. The evaluation results are shown in Table 2.

[Comparative Example 5]
The same operation as in Example 4 was carried out at a cylinder temperature of 350 ° C. and a screw rotation speed of 700 rpm. The resin temperature in the vicinity of the tip nozzle was 401 ° C. When pulling in a strand form from the nozzle at the end of the extruder, strand breakage frequently occurred and gas was ejected from the nozzle, making it difficult to achieve stable production. The evaluation results are shown in Table 2.

[Comparative Example 6]
The same operation as in Example 4 was carried out at a cylinder temperature of 300 ° C. and a screw rotation speed of 250 rpm. The resin temperature near the tip nozzle was 306 ° C. The evaluation results are shown in Table 2.

[Example 10]
The same procedure as in Example 4 was performed at an extrusion rate of 48 kg / hr. The resin temperature near the tip nozzle was 340 ° C., and the average residence time was 12.5 seconds. The evaluation results are shown in Table 2.

[Example 11]
The same procedure as in Example 4 was performed at an extrusion rate of 10 kg / hr. The resin temperature near the tip nozzle was 358 ° C., and the average residence time was 60 seconds. When the strand was drawn from the nozzle at the tip of the extruder, the strand sometimes broke, but production was possible. The evaluation results are shown in Table 3.

[Example 12]
The same procedure as in Example 4 was performed at an extrusion rate of 7 kg / hr. The resin temperature near the tip nozzle was 342 ° C., and the average residence time was 86 seconds. The evaluation results are shown in Table 3.

[Example 13]
It carried out similarly to Example 4 by setting the pressure reduction degree as 0.07 MPa. The resin temperature near the tip nozzle was 337 ° C. The evaluation results are shown in Table 3.

[Example 14]
It carried out similarly to Example 4 by setting the pressure reduction degree as 0.065 MPa. The resin temperature near the tip nozzle was 337 ° C. The evaluation results are shown in Table 3.

[Example 15]
50 parts by mass of JA416 (hereinafter abbreviated as “GF”) manufactured by Asahi Fiber Glass Co., Ltd. was further added from the side feeder with respect to 100 parts by mass of the polyamide component, and each was carried out in the same manner as Example 1. The resin temperature near the tip nozzle was 348 ° C., and the average residence time was 30 seconds. The evaluation results are shown in Table 4.

[Example 16]
The same procedure as in Example 15 was carried out, further adding 0.1 parts by weight of tris (2,4-t-di-butylphenyl) phosphite (IRGAFOS168, manufactured by Ciba Specialty Chemicals). The resin temperature near the tip nozzle was 351 ° C. The evaluation results are shown in Table 4.

[Example 17]
The process was performed in the same manner as in Example 16 with a degree of vacuum of 0.095 MPa. The resin temperature near the tip nozzle was 365 ° C. The evaluation results are shown in Table 4.

[Example 18]
The same procedure as in Example 17 was carried out by further blending 0.1 parts by mass of calcium montanate (Licomont CaV102 manufactured by Clariant). The resin temperature near the tip nozzle was 354 ° C. The evaluation results are shown in Table 4.

[ Reference Example 19]
It carried out similarly to Example 18 using 100 mass parts of PA66 as a polyamide component.
The resin temperature near the tip nozzle was 351 ° C. The evaluation results are shown in Table 4.

[Comparative Example 7]
50 parts by mass of PA66 and 50 parts by mass of PA6 were blended and melt kneaded using a twin screw extruder (CSKPER, ZSK25). From the side feeder, 50 parts by mass of GF was added to 100 parts by mass of the polyamide component. The screw rotation speed was 265 rpm, the cylinder temperature was 280 ° C., and the resin temperature near the tip nozzle was 309 ° C. The extrusion rate was 15 kg / hr and the average residence time was 30 seconds. Extrusion was performed at a reduced pressure of 0.095 MPa. The polymer was discharged in a strand form from the tip nozzle, and water-cooled and cut into pellets. The pellets were dried at 80 ° C. for 24 hours under a nitrogen atmosphere. The evaluation results are shown in Table 4.

[Comparative Example 8]
A cylinder temperature of 350 ° C. was used in the same manner as in Comparative Example 7. The resin temperature near the tip nozzle was 355 ° C. The evaluation results are shown in Table 4.

[Comparative Example 9]
It carried out similarly to the comparative example 7 using 100 mass parts of PA66 as a polyamide component. The resin temperature near the tip nozzle was 311 ° C. The evaluation results are shown in Table 4.

[Comparative Example 10]
It carried out similarly to the comparative example 8 using 100 mass parts of PA66 as a polyamide component. The resin temperature near the tip nozzle was 355 ° C. The evaluation results are shown in Table 5.

[Example 20]
The same procedure as in Example 18 was performed with a cylinder temperature of 350 ° C. and a screw rotation speed of 550 rpm. The resin temperature near the tip nozzle was 389 ° C. The evaluation results are shown in Table 5.

[Example 21]
The same procedure as in Example 18 was performed at a cylinder temperature of 310 ° C. The resin temperature near the tip nozzle was 315 ° C. The evaluation results are shown in Table 5.

[Example 22]
The same procedure as in Example 18 was performed at an extrusion rate of 30 kg / hr. The resin temperature near the tip nozzle was 345 ° C., and the average residence time was 15 seconds. The evaluation results are shown in Table 5.

[Example 23]
The same procedure as in Example 18 was performed at an extrusion rate of 7.6 kg / hr. The resin temperature near the tip nozzle was 362 ° C., and the average residence time was 59 seconds. The evaluation results are shown in Table 5.

[Comparative Example 11]
The same procedure as in Example 18 was performed with a cylinder temperature of 350 ° C. and a screw rotation speed of 600 rpm. The resin temperature near the tip nozzle was 399 ° C. When pulling in a strand form from the nozzle at the end of the extruder, strand breakage frequently occurred and gas was ejected from the nozzle, making it difficult to achieve stable production. The evaluation results are shown in Table 5.

[Comparative Example 12]
The same operation as in Example 18 was performed at a cylinder temperature of 300 ° C. and a screw rotation speed of 250 rpm. The resin temperature near the tip nozzle was 308 ° C. The evaluation results are shown in Table 5.

[Example 24]
The same procedure as in Example 18 was performed at an extrusion rate of 36 kg / hr. The resin temperature near the tip nozzle was 347 ° C., and the average residence time was 12.5 seconds. The evaluation results are shown in Table 5.

[Example 25]
It carried out similarly to Example 18 by making extrusion rate 7.5Kg / hr. The resin temperature near the tip nozzle was 352 ° C., and the average residence time was 60 seconds. When the strand was drawn from the nozzle at the tip of the extruder, the strand sometimes broke, but production was possible. The evaluation results are shown in Table 6.

[Example 26]
The same procedure as in Example 18 was performed at an extrusion rate of 5 kg / hr. The resin temperature near the tip nozzle was 349 ° C., and the average residence time was 90 seconds. The evaluation results are shown in Table 6.

[Example 27]
The process was performed in the same manner as in Example 18 with a degree of vacuum of 0.07 MPa. The resin temperature near the tip nozzle was 353 ° C. The evaluation results are shown in Table 6.

[Example 28]
It carried out similarly to Example 18 by setting the pressure reduction degree as 0.065 MPa. The resin temperature near the tip nozzle was 352 ° C. The evaluation results are shown in Table 6.

According to the present invention, it is possible to produce a high molecular weight polyamide resin which is excellent in mechanical properties and color tone after molding, and further excellent in film formation and workability during spinning.
The present invention has industrial applicability in fields such as automobile parts, electronic / electric parts, industrial machine parts, various gears, and extrusion applications.

Claims (5)

(A) A polyamide component containing two or more different polyamides selected from the group consisting of polyamide 6, polyamide 66, polyamide 6I and polyamide 6C, and (B) a metal phosphite metal salt having a resin temperature of 315 to 390 ° C. and a degree of vacuum A method for producing a polyamide resin, comprising a step of melt-kneading at 0.05 MPa or more.   Furthermore, the manufacturing method of the polyamide resin of Claim 1 which mix | blends and knead | mixes (C) a phosphite compound.   Furthermore, (D) The manufacturing method of the polyamide resin of Claim 1 or 2 which mix | blends and knead | mixes a molecular weight regulator.   With respect to 100 parts by mass of (A), 0.05 to 1 part by mass of (B), 0.05 to 1 part by mass of (C), and 0.01 to 1 of (D), if desired. The manufacturing method of the polyamide resin of any one of Claims 1-3 which mix | blends a mass part. (A) The manufacturing method of the polyamide resin of any one of Claims 1-4 in which a polyamide component contains 2 types of polyamides of the polyamide 6 and the polyamide 66 at least.