JP5673130B2 - Polyamide resin and method for producing the same - Google Patents

Description

  The present invention relates to a polyamide resin and a method for producing the same, and particularly relates to a polyamide resin having high heat resistance and excellent moldability and a method for producing the same.

  Polyamide resin is an engineering plastics with excellent mechanical strength such as impact resistance, friction resistance and wear resistance, heat resistance, and oil resistance. It is an automotive part, electronic / electric equipment part, OA equipment part, machine. It is widely used in fields such as parts, building materials and housing equipment, and the field of use has expanded in recent years.

  For example, many types of polyamide resins such as polyamide 6 and polyamide 66 are known. Metaxylylene adipamide (hereinafter, also referred to as “MXD6”) obtained from metaxylylenediamine and adipic acid is used. Unlike polyamide 6, polyamide 66, etc., it has an aromatic ring in the main chain, has high rigidity, low water absorption, excellent oil resistance, and has low molding shrinkage and small shrinkage and warpage in molding. It is also suitable for precision molding and is positioned as an extremely excellent polyamide resin. For these reasons, MXD6 is a molding material in various fields such as electronic / electric equipment parts, transport parts such as automobiles, general machine parts, precision machine parts, leisure sports equipment, civil engineering and building materials, especially for injection molding. In recent years, it has been increasingly used as a material.

  There is also a demand for a lighter and stronger polyamide resin material. As a xylylene-based polyamide resin lighter than MXD6, a xylylene-sebacamide-based polyamide resin (hereinafter referred to as “XD10”) obtained from xylenediamine and sebacic acid. ) Is known (see Patent Document 1), and is excellent in chemical resistance and impact resistance.

On the other hand, market needs in applications that require high heat resistance have increased greatly in recent years. For example, reflectors (reflectors) in LED lighting, LED mounting boards, and the like have high heat resistance during manufacture and use. is necessary. Patent Documents 2 to 4 propose using various polyamide resin compositions for such applications. Patent Document 4 discloses a composition in which a filler or the like is blended with a semi-aromatic polyamide resin composed of terephthalic acid, 1,9-nonanediamine and 2-methyl-1,8-octanediamine. However, this polyamide resin has a high melting point, for example, around 306 ° C., but the melt fluidity is poor. If the molding temperature is set high in order to increase the fluidity, the resin is easily decomposed and a large amount of gas is generated. It is not preferable because it is difficult to mold and has poor productivity.
In such a high heat resistance application, a polyamide resin having a melting point of 280 ° C. or higher, particularly exceeding 300 ° C. is desired. However, a polyamide resin having such a high melting point and excellent in molding processing is industrially used. The current situation is that the level is not satisfactory.

  Under these circumstances, the development of polyamide resins that excel in heat resistance, suppress resin decomposition during molding processing, generate less gas, increase the crystallization speed, increase the molding cycle, and excel in molding efficiency is strong. It was desired.

Japanese Unexamined Patent Publication No. 63-137756 JP 2008-182172 A JP 2009-99533 A JP 2009-202567 A

  The objective of this invention is providing the polyamide resin excellent in the moldability, having high heat resistance from the above situations.

  As a result of intensive studies to achieve the above object, the present inventors have identified a diamine component composed of xylylenediamine mainly composed of paraxylylenediamine and a dicarboxylic acid component composed mainly of sebacic acid. The present inventors have found that a polyamide resin having a molecular weight and having two or more melting points is a polyamide resin suitable for the above purpose, and completed the present invention.

That is, according to the first invention of the present invention, a polyamide resin in which 70 mol% or more of diamine structural units are derived from xylylenediamine units and 50 mol% or more of dicarboxylic acid structural units is derived from sebacic acid, ,
The xylylenediamine unit contains 50-100 mol% paraxylylenediamine-derived units, 0-50 mol% metaxylylenediamine-derived units,
A polyamide resin having a number average molecular weight (Mn) of 6,000 to 30,000 and having two or more melting points is provided.

  According to the second invention of the present invention, there is provided a polyamide resin characterized in that, in the first invention, the resin has two or more melting points within a temperature range of 250 to 330 ° C.

  According to the third invention of the present invention, there is provided a polyamide resin characterized in that, in the first or second invention, the resin has two or more melting points within a temperature range of 270 to 310 ° C. .

  According to a fourth aspect of the present invention, there is provided a polyamide resin according to any one of the first to third aspects, wherein the molecular weight distribution (Mw / Mn) is 2.1 to 3.1. Provided.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the molar ratio of the reacted diamine unit to the reacted dicarboxylic acid unit (number of moles of reacted diamine unit / reacted dicarboxylic acid) A polyamide resin is provided in which the number of moles of units is from 0.97 to 1.02.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the dicarboxylic acid component other than sebacic acid is an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. A polyamide resin is provided that is selected.

According to a seventh aspect of the present invention, there is provided a method for producing the polyamide resin according to any one of the first to sixth aspects,
A step of extracting the polyamide resin from the polymerization reaction vessel into a strand shape so as to be in the temperature range of the melting point of the polyamide resin to the melting point + 20 ° C.,
There is provided a method for producing a polyamide resin, comprising a step of cooling the extracted strand-like polyamide resin in 0 to 60 ° C cooling water.

  According to the eighth aspect of the present invention, in the seventh aspect, when the strand-like polyamide resin extracted from the polymerization reaction vessel is cooled, the time during which the strand-like polyamide resin contacts the cooling water is 2 to 2. The method for producing a polyamide resin of the first to sixth inventions characterized in that it is 60 seconds is provided.

  According to the ninth invention of the present invention, in the seventh or eighth invention, when the polyamide resin is extracted in a strand form from the polymerization reaction vessel, the strand extraction speed is 100 to 300 m / min. A method for producing the polyamide resin of the first to sixth inventions is provided.

Moreover, according to the tenth invention of the present invention, in any one of the seventh to ninth inventions, as a pre-process of the step of extracting the polyamide resin from the polymerization reaction vessel into a strand shape,
The step of melting the dicarboxylic acid, the step of continuously dropping the diamine into the molten dicarboxylic acid, the step of holding the polyamide resin at the melting point to the melting point + 30 ° C. for 0 to 60 minutes after completion of the diamine dropping, and the polycondensation reaction under a negative pressure The process for producing the polyamide resin of the first to sixth inventions is provided, which comprises the step of continuing the process.

Furthermore, according to the eleventh invention of the present invention, in any one of the seventh to ninth inventions, as a pre-process of the process of extracting the polyamide resin into a strand shape,
A step of melting and holding a salt composed of dicarboxylic acid and diamine under pressure, a step of raising the temperature while reducing the pressure, and a step of holding at a melting point of the polyamide resin to the melting point + 30 ° C. for 0 to 60 minutes. The manufacturing method of the polyamide resin of 6 invention is provided.

  According to the present invention, it is possible to provide a polyamide resin that is excellent in heat resistance and molding processability and in which decomposition of the resin during molding process is suppressed. The polyamide resin of the present invention is also expected to be used in the field of high heat resistant parts and the like to which polyamide resin has not been applied so far.

No xylylene sebacamide polyamide resin having two or more melting points has been known so far. In the present invention, the composition of the raw material monomer should be in a specific range, the reaction molar ratio should be in an appropriate range, and the reaction temperature, reaction pressure, and reaction time during polymerization should be controlled in an optimal range. When extracting the polymerized polyamide resin in the form of a strand, the temperature of the strand at the time of extraction, the cooling water temperature and the cooling time when cooling the extracted strand are within a specific range, and the strand take-up speed is optimized Surprisingly, it is thought that a phenomenon occurs in which the resulting polyamide resin has a single crystal structure and a plurality of different crystal structures exist in a stable form. For this reason, although it is a polymer of the same composition, a component having a relatively low melting point and a component having a relatively high melting point are present, and it is considered that a polyamide resin having both heat resistance and molding processability is obtained.
For example, in polyamide 6, it is known that α-type crystals and γ-type crystals exist, the density varies depending on the existence ratio, and the crystal structure changes at a certain temperature. It has never been known to have a different melting point. Further, such knowledge has not been known for xylylene sebacamide-based polyamide resins.

The polyamide resin of the present invention is a polyamide resin in which 70 mol% or more of diamine structural units are derived from xylylenediamine units, and 50 mol% or more of dicarboxylic acid structural units are derived from sebacic acid,
The xylylenediamine unit contains 50 to 100 mol% of the unit derived from paraxylylenediamine, 0 to 50 mol% of the unit derived from metaxylylenediamine,
The number average molecular weight (Mn) is 6,000 to 30,000 and has two or more melting points.

Hereinafter, the polyamide resin of the present invention and the method for producing the polyamide resin will be described in detail.
In addition, in this-application specification, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit unless there is particular notice.

The diamine constituent unit of the polyamide resin of the present invention is 70 mol% or more of xylylenediamine-derived units, and the xylylenediamine-derived units are 50 to 100 mol% of paraxylylenediamine-derived units, metaxylylene. It consists of 0-50 mol% of a range amine origin unit.
When the xylylenediamine derived unit is less than 70 mol%, the heat resistance and chemical resistance are lowered. The unit derived from xylylenediamine is preferably 80 mol% or more, more preferably 90 mol% or more, further 95 mol% or more, and particularly 98 mol% or more.

  Moreover, heat resistance and crystallinity will fall if the unit derived from paraxylylenediamine is less than 50 mol% among the units derived from xylylenediamine. Further, among the xylylenediamine-derived units, metaxylylenediamine-derived units may not be present, but the upper limit is 50 mol%, preferably 30 mol% or less, more preferably 20 mol% or less, and further 10 mol%. In particular, the amount is 5 mol% or less. If it exceeds 50 mol%, the crystallinity of the polyamide resin is lowered, and the melting point becomes single, which is not preferable.

  Further, the dicarboxylic acid structural unit of the polyamide resin of the present invention is a unit in which 50 mol% or more is derived from sebacic acid, preferably 60 mol% or more, more preferably 70 mol% or more, and further 80 mol% or more. In particular, it is 90 mol% or more, most preferably 95 mol% or more. If it is this range, it can be set as the polyamide resin excellent in heat resistance and excellent in moldability.

As the dicarboxylic acid component other than sebacic acid, a dicarboxylic acid component mainly composed of an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms is preferable. For example, adipic acid, succinic acid, glutaric acid, pimelic acid, Examples include aliphatic dicarboxylic acids such as suberic acid, azelaic acid, undecanedioic acid, and dodecanedioic acid. Of these, adipic acid, succinic acid, undecanedioic acid, dodecanedioic acid and the like are preferably used, and adipic acid is particularly preferable. By using adipic acid in combination, it becomes easy to control the elastic modulus and crystallinity.
The amount of α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms other than sebacic acid is less than 50 mol%, preferably 40 mol% or less, more preferably 30 mol% or less, and still more preferably 20 The mol% or less, particularly preferably 10 mol% or less, and most preferably 5 mol% or less.

In addition, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid can be used in combination.
Examples of dicarboxylic acid components other than linear aliphatic dicarboxylic acids that can be used as the dicarboxylic acid component include phthalic acid compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2, Examples thereof include naphthalene dicarboxylic acids such as isomers such as 6-naphthalenedicarboxylic acid and 2,7-naphthalenedicarboxylic acid, and one kind or a mixture of two or more kinds can be used.
Also, monocarboxylic acids such as benzoic acid, propionic acid and butyric acid, polycarboxylic acids such as trimellitic acid and pyromellitic acid, carboxylic acid anhydrides such as trimellitic anhydride and pyromellitic anhydride may be used in combination. it can.

  When a dicarboxylic acid other than a linear aliphatic dicarboxylic acid is used as the dicarboxylic acid component, the proportion is preferably 30 mol% or less of the dicarboxylic acid structural unit. From the viewpoint of molding processability, among the above, isophthalic acid Is preferred. The proportion of isophthalic acid is 30 mol% or less of the dicarboxylic acid structural unit, preferably 1 to 25 mol%, particularly preferably 5 to 20 mol%.

  As a diamine component other than xylylenediamine that can be used in the range of 30 mol% or less of the diamine component as a raw material diamine component of the polyamide resin, tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine , Octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, aliphatic diamine such as 2,2,4-trimethyl-hexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-bis (Aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2,2-bis (4- Cycloaliphatic diamines such as minocyclohexyl) propane, bis (aminomethyl) decalin (including structural isomers), bis (aminomethyl) tricyclodecane (including structural isomers), and bis (4-aminophenyl) Examples include diamines having aromatic rings such as ether, paraphenylenediamine, and bis (aminomethyl) naphthalene (including structural isomers), and one or a mixture of two or more can be used.

  When a diamine other than xylylenediamine is used as the raw material diamine component, it is 30 mol% or less of the diamine structural unit, preferably 25 mol% or less, more preferably 20 mol% or less, and even more preferably 15 mol% or less. Particularly preferred is 10 mol% or less, and most preferred is 5 mol% or less.

The polyamide resin of the present invention has two or more melting points. The melting point in the present invention is the temperature at the peak top of the endothermic peak at the time of temperature rise observed by the differential scanning calorimetry (DSC) method. Specifically, it can be obtained in the following manner.
The polyamide resin is melted by raising the temperature from 30 ° C. to the expected melting point or higher, usually to the expected melting point + 30 ° C. at a rate of 10 ° C./min. The melting point can be determined from the peak top of the endothermic peak observed at this time.
Normally, a polyamide resin has one endothermic peak observed and has a single melting point, but the polyamide resin of the present invention differs from conventional polyamide resins in that it has two or more melting points, usually 2 Have one.
The two or more melting points of the polyamide resin of the present invention are usually in the range of 250 to 330 ° C, preferably 260 to 320 ° C, more preferably 270 to 310 ° C, particularly preferably 275 to 305 ° C.
By having two or more melting points, preferably in such a temperature range, a polyamide resin having good heat resistance and moldability is obtained.

  Moreover, it is preferable that the glass transition point of the polyamide resin of this invention is the range of 70-120 degreeC, More preferably, it is 75-110 degreeC.

  In the present invention, the glass transition point of the polyamide resin can be measured by the differential scanning calorimetry (DSC) method. The glass transition point measured by heating and melting the sample once, rapidly cooling, and raising the temperature again is measured. Say. Specifically, for example, the temperature is raised at a rate of 10 ° C./min from 30 ° C. to a temperature higher than the expected melting point, usually the expected melting point + 30 ° C., and the polyamide resin is melted and then rapidly cooled. Next, the glass transition point can be determined by raising the temperature to a temperature equal to or higher than the melting point at a rate of 10 ° C./min.

  The polyamide resin of the present invention has a number average molecular weight of 6,000 to 30,000. When the number average molecular weight is less than 6,000, the mechanical properties may not be good. When the number average molecular weight exceeds 30,000, the viscosity becomes high, and a lot of heat energy is required during the molding process. is there. The preferable range of the number average molecular weight is 8,000 to 25,000, more preferably 10,000 to 20,000, and further preferably 11,000 to 18,000.

The number average molecular weight here is calculated from the following formula from the terminal amino group concentration [NH ₂ ] (μ equivalent / g) and the terminal carboxyl group concentration [COOH] (μ equivalent / g) of the polyamide resin. is there.
Number average molecular weight = 2,000,000 / ([COOH] + [NH ₂ ])

The polyamide resin of the present invention preferably has a molecular weight distribution (weight average molecular weight / number average molecular weight (Mw / Mn)) of 2.1 to 3.1. The molecular weight distribution is more preferably 2.2 to 3.0, still more preferably 2.3 to 2.9. By setting the molecular weight distribution in such a range, the balance between the heat resistance strength and the moldability can be excellent.
The molecular weight distribution of the polyamide resin can be adjusted, for example, by selecting the polymerization reaction conditions such as the type and amount of the initiator and catalyst used during polymerization, the reaction temperature, pressure, and time.

  The molecular weight distribution can be determined by a conventional method, for example, gel permeation chromatography (GPC). Specifically, “HLC-8320GPC” manufactured by Tosoh Corp. is used as an apparatus, and “TSK gel Super” manufactured by Tosoh Corp. is used as a column. HM-H ", eluent sodium trifluoroacetate concentration 10 mmol / l hexafluoroisopropanol (HFIP), resin concentration 0.02% by mass, column temperature 40 ° C, flow rate 0.3 ml / min, refractive index It can be measured under the condition of the detector (RI) and obtained as a standard polymethyl methacrylate equivalent value.

The polyamide resin of the present invention has a molar ratio of reacted diamine units to reacted dicarboxylic acid units (number of moles of reacted diamine units / number of moles of reacted dicarboxylic acid units, hereinafter sometimes referred to as “reaction molar ratio”). Is preferably 0.97 to 1.02. By setting it as such a range, it exists in the tendency which becomes the polyamide resin which suppresses decomposition | disassembly of the resin at the time of a shaping | molding process, and has the stable fluidity | liquidity. In addition, when melt molding is further performed by an extruder or a molding machine and the amidation reaction is further performed, the reaction is easily advanced to an optimum range without excessive progress of the amidation reaction.
The reaction molar ratio is more preferably less than 1.0, further preferably less than 0.995, particularly less than 0.990, and the lower limit is more preferably 0.975 or more, and further preferably 0.98 or more. .

Here, the reaction molar ratio (r) is obtained by the following equation.
r = (1-cN-b (CN)) / (1-cC + a (CN))
Where
a: M1 / 2
b: M2 / 2
c: 18.015 (molecular weight of water)
M1: Molecular weight of diamine (g / mol)
M2: Molecular weight of dicarboxylic acid (g / mol)
N: Terminal amino group concentration (equivalent / g)
C: Terminal carboxyl group concentration (equivalent / g)

  In addition, when synthesizing a polyamide resin from monomers having different molecular weights as diamine and dicarboxylic acid components, it goes without saying that M1 and M2 are calculated according to the blending ratio (molar ratio) of the monomers blended as raw materials. If the inside of the synthesis kettle is a complete closed system, the molar ratio of the charged monomers and the reaction molar ratio are the same, but the actual synthesis apparatus cannot be a complete closed system. The ratio and the reaction molar ratio do not always coincide. Since the charged monomer does not always react completely, the charged molar ratio and the reaction molar ratio are not always the same. Therefore, the reaction molar ratio means the molar ratio of the actually reacted monomer obtained from the end group concentration of the finished polyamide resin.

The reaction molar ratio of the polyamide resin is adjusted by appropriately adjusting the reaction conditions such as the charged molar ratio of the raw dicarboxylic acid component and the diamine component, the reaction time, the reaction temperature, the xylylenediamine dripping rate, the pressure in the kettle, and the pressure reduction start timing. It is possible by making it a value.
When the production method of the polyamide resin is a so-called salt method, in order to set the reaction molar ratio to 0.97 to 1.02, specifically, for example, the raw material diamine component / raw material dicarboxylic acid component ratio is within this range. Set and proceed the reaction sufficiently. In addition, in the case of a method in which a diamine is continuously added dropwise to a molten dicarboxylic acid, the amount of diamine to be refluxed during the addition of the diamine is controlled and the added diamine is added to the reaction system in addition to setting the charging ratio within this range. It can also be removed outside. Specifically, by controlling the temperature of the reflux tower to the optimum range and controlling the packing tower packing, so-called Raschig ring, Lessing ring, saddle, etc. to an appropriate shape and filling amount, the diamine is removed from the system. Remove it. Moreover, unreacted diamine can also be removed out of the system by shortening the reaction time after diamine dropping. Furthermore, unreacted diamine can also be removed out of the reaction system as needed by controlling the dropping rate of diamine. By these methods, it is possible to control the reaction molar ratio within a predetermined range even if the charging ratio deviates from the desired range.

The polyamide resin of the present invention preferably has a terminal amino group concentration of 10 to 100 μequivalent / g, more preferably 15 to 70 μequivalent / g, still more preferably 20 to 50 μequivalent / g, and a terminal carboxyl group concentration of preferably 50 to 50. It is 200 µequivalent / g, more preferably 60 to 170 µequivalent / g, still more preferably 70 to 150 µequivalent / g.
By setting the terminal amino group concentration and the terminal carboxyl group concentration within the above ranges, the molecular weight of the polyamide resin becomes an appropriate range, the mechanical properties become better, the resin is hardly decomposed during molding, and the generation of gas is suppressed. Tend to be good.

Further, the ratio of the terminal amino group concentration to the terminal carboxyl group concentration ([NH ₂ ] / [COOH]) is preferably 0.7 or less, more preferably 0.6 or less, particularly preferably 0. .5 or less. When this ratio is larger than 0.6, the heat resistance of the polyamide resin is poor, and there is a tendency that discoloration or gas is easily generated during molding.

  The terminal amino group concentration can be measured by dissolving 0.5 g of polyamide resin in 30 ml of a phenol / methanol (4: 1) mixed solution with stirring at 20 to 30 ° C. and titrating with 0.01 N hydrochloric acid. As for the terminal carboxyl group concentration, 0.1 g of polyamide resin is dissolved in 30 ml of benzyl alcohol at 200 ° C., and 0.1 ml of phenol red solution is added in the range of 160 ° C. to 165 ° C. The solution was titrated with a titration solution (KOH concentration 0.01 mol / l) in which 0.132 g of KOH was dissolved in 200 ml of benzyl alcohol, and when the color change changed from yellow to red, the end point was reached. Can be calculated.

The polyamide resin of the present invention includes a diamine component containing 70 mol% or more of xylylenediamine containing 50 to 100 mol% of paraxylylenediamine and 0 to 50 mol% of metaxylylenediamine, and 50 mol% or more of sebacic acid. It can be obtained by polycondensation with a dicarboxylic acid component, and its production method is not particularly limited, and it is produced by melt polymerization such as atmospheric pressure melt polymerization or pressure melt polymerization.
For example, a polyamide salt composed of paraxylylenediamine (further metaxylylenediamine, etc.) and sebacic acid (further, adipic acid, etc.) is heated in the presence of water under pressure, added water and condensed water It is produced by a method of polymerizing in a molten state while removing the water. It can also be produced by a method in which paraxylylenediamine or the like is directly added to a molten sebacic acid or the like and polycondensed under normal pressure or pressure.

  The polycondensation is carried out by continuously or intermittently adding the diamine component under pressure while stirring the dicarboxylic acid component in a molten state in the reaction vessel. It is preferable to maintain the molten state of the reaction mixture by sequentially increasing the temperature of the reaction mixture during the addition of the diamine component, thereby controlling the temperature of the reaction mixture in the range of the melting point to the melting point + 30 ° C. If the temperature of the reaction mixture is lower than its melting point, the reaction mixture may solidify in the reaction vessel. If the melting point is higher than + 30 ° C, the reaction mixture may be deteriorated, which is not preferable. At the end of the addition, it is preferable that the temperature of the reaction mixture be equal to or higher than the melting point of the target polyamide resin while maintaining the molten state of the reaction mixture. The melting point of the reaction mixture can be measured successively by DSC or the like as appropriate. In addition, melting | fusing point here means the temperature of the peak top of the peak of a high temperature side among the several endothermic peaks which exist when DSC measurement is performed.

The rate of addition of the diamine component is the heat of formation of the amidation reaction, the amount of heat consumed for distilling off the condensation product water, the amount of heat supplied from the heating medium through the reaction vessel wall to the reaction mixture, and the condensation product water and the raw material compound are separated. The reaction system is selected so as to be maintained in a uniform molten state in consideration of the structure and the like of the portion to be processed. The time required for the addition of the diamine component varies depending on the scale of the reaction vessel, but is usually in the range of 0.5 to 5 hours. During this time, the condensed water produced as the reaction proceeds is distilled out of the reaction system. The raw materials such as diamine and dicarboxylic acid that are scattered are separated from the condensed water and returned to the reaction vessel, but the amount can be controlled. For example, the temperature of the reflux tower can be controlled within the optimum range, It can be controlled by controlling the filling, so-called Raschig ring, Lessing ring, saddle, etc. to an appropriate shape and filling amount. A separator is suitable for separating the raw material and the condensed water, and the condensed water is preferably distilled through the whole condenser.
The pressure inside the reaction vessel during the polycondensation reaction is preferably 0.1 to 0.6 MPa, and more preferably 0.2 to 0.5 MPa. The pressurization may be performed with an inert gas such as nitrogen, or with condensed water vapor generated during the reaction.

  After completion of the addition of the diamine component, the pressure may be reduced and the polycondensation reaction may be terminated when the pressure reaches normal pressure. . When the polycondensation reaction is further continued under a negative pressure, it is preferable to finally reduce the pressure of the reaction system to 0.08 MPa or less. There is no particular limitation on the time from the end of addition to the start of pressure reduction, but it is preferable to start the pressure reduction within 30 minutes after the end of dropping. The speed at which the unreacted diamine is not distilled out of the system together with water during the pressure reduction is selected as the pressure reduction speed, and is selected from the range of, for example, 0.1 to 1 MPa / hour. Decreasing the pressure reduction rate is not preferable because it not only increases the time required for production but also requires time for pressure reduction, which may cause thermal degradation of the resulting polyamide resin.

  After completion of the dropping, the temperature at which the polycondensation reaction is continued under normal pressure or negative pressure is a temperature at which the obtained polyamide does not solidify, that is, within the range of the melting point of the obtained polyamide resin to the melting point + 30 ° C. Is preferred. In addition, melting | fusing point here means the temperature of the peak top of the peak of a high temperature side among the several endothermic peaks which exist when DSC measurement is performed.

  The melt polycondensation is performed in the presence of a polymerization catalyst. As a polymerization catalyst, phosphorus compounds, such as phosphoric acid, phosphorous acid, and hypophosphorous acid, those salts, and ester compounds are mentioned. Examples of the salt include potassium, sodium, magnesium, calcium, zinc, cobalt, manganese, tin, tungsten, vanadium, germanium, titanium, antimony, and other metal salts and ammonium salts. Examples of ester compounds include ethyl ester, isopropyl ester, butyl ester, hexyl ester, octadecyl ester, stearyl ester, phenyl ester and the like.

  In order to prevent the polymerization catalyst from aggregating in the polyamide resin or causing an abnormal reaction due to deterioration during heating, an alkali metal compound or an alkaline earth metal compound may be used in combination. Specific examples thereof include alkali metal hydroxides and alkaline earth metal hydroxides such as sodium hydroxide, calcium hydroxide, potassium hydroxide, and magnesium hydroxide, and carbonic acid, boric acid, acetic acid, propionic acid, butyric acid, Isobutyric acid, crotonic acid, valeric acid, caproic acid, isocaproic acid, enanthic acid, caprylic acid, pelargonic acid, stearic acid, cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, hydrocinnamic acid, γ-phenylbutyric acid, p-phenoxybenzoic acid , O-oxycinnamic acid, o-β-chlorophenylpropionic acid, alkali metal salts and alkaline earth metal salts of m-chlorophenylpropionic acid, but are not limited thereto.

In order to obtain the above-described polyamide resin of the present invention, the melt polymerization is preferably performed by applying the following methods (1), (2) or (3), or a combination of these methods. Can do.
(1) When producing the polyamide resin of the present invention, the step of extracting the polyamide resin from the polymerization reaction vessel into a strand shape so as to be in the temperature range of the melting point of the polyamide resin to the melting point + 20 ° C., the extracted strand-like polyamide A method comprising a step of cooling a resin in cooling water at 0 to 60 ° C.
(2) As a pre-process of the process of extracting the polyamide resin from the polymerization reaction vessel into a strand shape,
The step of melting the dicarboxylic acid, the step of continuously dropping the diamine into the molten dicarboxylic acid, the step of holding the polyamide resin at the melting point to the melting point + 30 ° C. for 0 to 60 minutes after completion of the diamine dropping, and the polycondensation reaction under a negative pressure The method including the process of continuing.
(3) As a pre-process of the step of extracting the polyamide resin from the polymerization reaction vessel in the form of a strand, a step of melting and holding a salt composed of dicarboxylic acid and diamine, a step of raising the temperature while reducing the pressure, and a melting point to a melting point of the polyamide resin The method including the process hold | maintained at +30 degreeC for 0 to 60 minutes.
The melting points in the above (1) to (3) mean the temperature at the peak top of the peak on the high temperature side among a plurality of endothermic peaks when DSC measurement is performed.

  In the method (1), the polyamide resin is cooled in a specific temperature range while being drawn out in a strand shape under a specific temperature condition. It is considered that a plurality of crystal structures having different melting points can be immobilized while being a polyamide resin having a composition. The temperature of the polyamide resin at the time of extracting the strand is preferably a melting point to a melting point + 15 ° C. The strand is cooled in 0 to 60 ° C. cooling water, preferably 10 to 50 ° C., more preferably 20 to 45 ° C.

Moreover, about 2 to 60 second is preferable and, as for the time which makes a strand contact with cooling water, 5 to 50 second is more preferable.
By setting it as such a range, it is thought that several crystal structures from which melting | fusing point differs can be fix | immobilized, although it is a polyamide resin of a single composition. If the cooling time is 2 seconds or less, the cooling may be insufficient and the crystal structure may not be fixed, and an event such as winding of a strand around the cutter during pelletizing may occur, resulting in poor productivity. Moreover, when cooling time exceeds 60 second, problems, such as the moisture content of the obtained polyamide resin becoming too high, may arise. In addition, the said cooling time can be suitably adjusted with the distance which a strand contacts water in a cooling water tank, the length of a cooling water tank, or the time which sprays and sprays cooling water on a strand.

  The strand take-up speed is preferably from 100 to 300 m / min, more preferably from 120 to 280 m / min, further preferably from 140 to 260 m / min, particularly preferably from 150 to 250 m / min. It is considered that the crystal structure of the polyamide resin can be fixed to a plurality of crystal structures having different melting points within such a range. Moreover, it is preferable that the moisture content of the pellets obtained is not excessive. Furthermore, it is preferable because pelletizing becomes easy and productivity is improved. The strand take-up speed can be adjusted by the rotation speed of the pelletizer and the pressure in the reaction vessel at the time of extraction.

The method of (2) is a step of melting the dicarboxylic acid, a step of continuously dropping the diamine into the molten dicarboxylic acid, a step of continuously dropping the diamine into the molten dicarboxylic acid, It is a method including the step of maintaining the melting point of the polyamide resin to the melting point + 30 ° C. for 0 to 60 minutes, and the step of continuing the polycondensation reaction under a negative pressure.
In the step of melting the dicarboxylic acid, prior to the polycondensation step, the solid dicarboxylic acid may be charged into the reactor to be heated and melted, or the dicarboxylic acid previously melted may be charged into the reaction vessel.
In the step of continuously dropping the diamine into the molten dicarboxylic acid, the temperature of the produced polyamide oligomer does not solidify to a temperature not solidified to a temperature of + 30 ° C., while controlling the inside of the reaction vessel, It is preferable to raise the temperature in the reaction vessel continuously. The temperature in the reaction vessel is preferably between the melting point of the polyamide resin and the melting point of 30 ° C. when the entire amount of diamine has been dropped. During this time, the inside of the reaction vessel is preferably replaced with nitrogen. During this time, the inside of the reaction vessel is preferably mixed with a stirring blade, and the inside of the reaction vessel is preferably in a uniform fluid state.

  During this time, the inside of the reaction vessel is preferably pressurized. Preferably it is 0.1-1 MPa, More preferably, it is 0.2-0.6 MPa, More preferably, it is 0.3-0.5 MPa. Pressurization may be performed with nitrogen or steam may be used. Through this process, a polyamide resin having a uniform property can be produced with high productivity.

In the method (2), the polyamide resin obtained through these steps by passing through the step of maintaining the melting point of the polyamide resin to the melting point + 30 ° C. for 0 to 60 minutes, and further continuing the polycondensation reaction under a negative pressure, It tends to be a polyamide resin having a plurality of melting points.
If the step of maintaining the melting point of the polyamide resin to the melting point + 30 ° C. is longer than 60 minutes, the melting point of the polyamide resin may become one, which is not preferable. The step of maintaining the melting point to the melting point + 30 ° C. is more preferably 1 to 40 minutes, further preferably 1 to 30 minutes, and particularly preferably 1 to 20 minutes.

  In the step of continuing the polycondensation reaction under a negative pressure, the pressure is preferably 0.05 MPa to less than atmospheric pressure, more preferably 0.06 to 0.09 MPa, and even more preferably 0.07 to 0.085 MPa. . Further, the time at that time is preferably 1 to 60 minutes. 1-40 minutes is more preferable, 1-30 minutes is further more preferable, Especially preferably, it is 1-20 minutes. The reaction temperature is preferably from melting point to melting point + 30 ° C., more preferably from melting point to melting point + 20 ° C. By continuing the polycondensation reaction under the above-described negative pressure conditions, the polyamide resin can be adjusted to a desired molecular weight, and the melting point of the polyamide resin can be fixed to a plurality.

The method (3) includes a step of melting and holding a salt composed of dicarboxylic acid and diamine under pressure, a step of raising the temperature while reducing the pressure, and a step of holding at a melting point of the polyamide resin to the melting point + 30 ° C. for 0 to 60 minutes. .
The step of melting and holding a salt composed of a dicarboxylic acid and a diamine under pressure, and the step of raising the temperature while reducing the pressure are a general salt method, but in the present invention, the salt composed of a dicarboxylic acid and a diamine is under pressure. In the melting and holding step, the temperature is preferably the melting point of the polyamide oligomer to the melting point + 30 ° C., more preferably the melting point of the polyamide oligomer to the melting point + 20 ° C., and the pressure is preferably 1 to 2 MPa, more preferably 1.5 to 1. While controlling the inside of the reaction vessel at 9 MPa, the melt is preferably held for 60 to 300 minutes, more preferably 90 to 240 minutes.

In the step of raising the temperature while reducing the pressure, the pressure reduction rate is preferably 1 to 2 MPa / hour, more preferably 1.5 to 1.8 MPa / hour, and the temperature raising rate is preferably 10 to 100 ° C./hour, more preferably. The pressure is reduced and the temperature is raised at 20 to 80 ° C./hour. The pressure in the holding step after the pressure reduction / temperature rise is preferably 0.05 MPa to less than atmospheric pressure, more preferably 0.06 to 0.09 MPa, and still more preferably 0.07 to 0.085 MPa. Further, the time at that time is preferably 1 to 60 minutes. 1-40 minutes is more preferable, 1-30 minutes is further more preferable, Especially preferably, it is 1-20 minutes. In addition, the melting point is preferably from the melting point to the melting point + 30 ° C., more preferably from the melting point to the melting point + 20 ° C.
And it hold | maintains for 0 to 60 minutes at melting | fusing point-melting point +30 degreeC of a polyamide resin. By passing through these steps, the polyamide resin obtained through these steps can be a polyamide resin having a plurality of melting points. If the step of maintaining the melting point of the polyamide resin to the melting point + 30 ° C. is longer than 60 minutes, the melting point of the polyamide resin may become one, which is not preferable. The step of maintaining the melting point to the melting point + 30 ° C. is more preferably 1 to 40 minutes, further preferably 1 to 30 minutes, and particularly preferably 1 to 20 minutes.

  In addition to the reaction conditions for the melt polycondensation described above, the charge ratio of the raw dicarboxylic acid component and the diamine component is in the above-mentioned range, the polymerization catalyst and the molecular weight regulator are appropriately selected, and the polymerization conditions are selected in the above-mentioned range. A polyamide resin having a number average molecular weight (Mn) of 6,000 to 30,000 can be more suitably produced.

The polyamide resin of the present invention is preferably a polyamide resin composition containing a phosphorus compound in order to increase the processing stability during melt molding or to prevent the polyamide resin from being colored. As the phosphorus compound, a phosphorus compound containing an alkali metal or an alkaline earth metal is preferably used, and examples thereof include phosphates such as sodium, magnesium, and calcium, hypophosphites, and phosphites. Among these, it is preferable to contain a hypophosphite of an alkali metal or an alkaline earth metal because the anti-coloring effect of the polyamide resin is particularly excellent. When using a phosphorus compound, it should be contained in the polyamide resin so that the phosphorus atom concentration in the finally obtained polyamide resin is 1 to 200 ppm, preferably 5 to 160 ppm, more preferably 10 to 100 ppm or less. Is desirable.
In addition to the above phosphorus compounds, the polyamide resin of the present invention includes lubricants, matting agents, heat stabilizers, weather stabilizers, ultraviolet absorbers, nucleating agents, plastics, as long as the effects of the present invention are not impaired. It may be a composition to which additives such as an agent, a flame retardant, an antistatic agent, an anti-coloring agent and an anti-gelling agent are added, but is not limited to the above-described ones, and various materials can be used. You may mix and add.

  It is also preferable to mix a carbodiimide compound with the polyamide resin of the present invention. Preferred examples of the carbodiimide compound include aromatic, aliphatic or alicyclic polycarbodiimide compounds produced by various methods. Among these, an aliphatic or alicyclic polycarbodiimide compound is preferable, and an alicyclic polycarbodiimide compound is more preferably used from the viewpoint of melt kneading properties during extrusion and the like.

  These carbodiimide compounds can be produced by decarboxylation condensation reaction of organic polyisocyanate. For example, a method of synthesizing various organic polyisocyanates by decarboxylation condensation reaction at a temperature of about 70 ° C. or higher in an inert solvent or without using a solvent in the presence of a carbodiimidization catalyst can be exemplified. . The isocyanate group content is preferably 0.1 to 5%, more preferably 1 to 3%. By setting it as the above ranges, the reaction with the polyamide resin becomes easy and the hydrolysis resistance tends to be good.

As the organic polyisocyanate that is a raw material for synthesizing the carbodiimide compound, for example, various organic diisocyanates such as aromatic diisocyanate, aliphatic diisocyanate, and alicyclic diisocyanate, and mixtures thereof can be used.
Specific examples of the organic diisocyanate include 1,5-naphthalene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2 , 4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4-diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene Range isocyanate, 2,6-diisopropylphenyl isocyanate, 1,3,5-triisopropylbenzene-2,4-dii Cyanate, methylenebis (4,1-cyclohexylene) = can be exemplified diisocyanate may be used in combination of two or more thereof. Among these, dicyclohexylmethane-4,4-diisocyanate and methylenebis (4,1-cyclohexylene) = diisocyanate are preferable.

  It is also preferred to use an end-capping agent such as monoisocyanate in order to seal the end of the carbodiimide compound and control the degree of polymerization. Examples of the monoisocyanate include phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, and naphthyl isocyanate, and two or more kinds may be used in combination.

  In addition, as terminal blocker, it is not limited to said monoisocyanate, What is necessary is just an active hydrogen compound which can react with isocyanate. Examples of such active hydrogen compounds include aliphatic, aromatic, and alicyclic compounds such as methanol, ethanol, phenol, cyclohexanol, N-methylethanolamine, polyethylene glycol monomethyl ether, and polypropylene glycol monomethyl ether. -OH group compounds, secondary amines such as diethylamine and dicyclohexylamine, primary amines such as butylamine and cyclohexylamine, carboxylic acids such as succinic acid, benzoic acid and cyclohexanecarboxylic acid, ethyl mercaptan, allyl mercaptan, thiophenol, etc. Examples of these compounds include thiols and compounds having an epoxy group, and two or more of them may be used in combination.

  Examples of the carbodiimidization catalyst include 1-phenyl-2-phospholene-1-oxide, 3-methyl-1-phenyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 3- Metal catalysts such as methyl-2-phospholene-1-oxide and phospholene oxides such as these 3-phospholene isomers, tetrabutyl titanate, etc. can be used. -Methyl-1-phenyl-2-phospholene-1-oxide is preferred. Two or more carbodiimidization catalysts may be used in combination.

  The preferable content of the carbodiimide compound is 0.1 to 2 parts by mass, more preferably 0.2 to 1.5 parts by mass, and still more preferably 0.3 to 1.5 parts by mass with respect to 100 parts by mass of the polyamide resin. Part by mass. If the amount is less than 0.1 parts by mass, the resin composition does not have sufficient hydrolysis resistance, uneven discharge during melt kneading such as extrusion tends to occur, and melt kneading tends to be insufficient. On the other hand, when it exceeds 2 parts by mass, the viscosity of the resin composition during melt kneading is remarkably increased, and melt kneadability and moldability are liable to deteriorate.

  Moreover, it is also preferable to mix | blend a stabilizer with the polyamide resin of this invention. Examples of the stabilizer include, for example, phosphorus-based, hindered phenol-based, hindered amine-based, organic sulfur-based, oxalic acid anilide-based, aromatic secondary amine-based organic stabilizers, copper-based compounds, halide-based inorganic systems, and the like. Stabilizers are preferred. As a phosphorus stabilizer, a phosphite compound and a phosphonite compound are preferable.

  Examples of the phosphite compound include distearyl pentaerythritol diphosphite, dinonylphenyl pentaerythritol diphosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, and bis (2,6- Di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-ethylphenyl) pentaerythritol diphosphite, bis (2,6-di-t- Butyl-4-isopropylphenyl) pentaerythritol diphosphite, bis (2,4,6-tri-t-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-sec-) Butylphenyl) pentaerythritol diphosphite, bis (2,6-di-) -Butyl-4-t-octylphenyl) pentaerythritol diphosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite and the like, and in particular, bis (2,6-di-t-butyl- 4-methylphenyl) pentaerythritol diphosphite and bis (2,4-dicumylphenyl) pentaerythritol diphosphite are preferred.

  Examples of the phosphonite compound include tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2,5-di-t-butylphenyl) -4,4′-. Biphenylene diphosphonite, tetrakis (2,3,4-trimethylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,3-dimethyl-5-ethylphenyl) -4,4'-biphenylene diphosphonite Tetrakis (2,6-di-t-butyl-5-ethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,3,4-tributylphenyl) -4,4'-biphenylenediphosphonite , Tetrakis (2,4,6-tri-t-butylphenyl) -4,4′-biphenylenediphosphonite, etc. Tetrakis (2,4-di -t- butyl-phenyl) -4,4'-biphenylene phosphonite are preferred.

  Examples of the hindered phenol stabilizer include n-octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,6-hexanediol-bis [3- (3,5 -Di-t-butyl-4-hydroxyphenyl) propionate], pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 3,9-bis [1,1- Dimethyl-2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, triethylene glycol -Bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 3,5-di-tert-butyl-4-hydro Cybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 2,2-thio-diethylenebis [3 -(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, N, N'-hexamethylenebis (3 , 5-di-t-butyl-4-hydroxy-hydrocinnamide) and the like. Among these, n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 1,6-hexanediol-bis [3- (3,5-t-butyl-4 -Hydroxyphenyl) propionate], pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 3,9-bis [1,1-dimethyl-2- {β- ( 3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, N, N′-hexamethylenebis (3 5-di-t-butyl-4-hydroxy-hydrocinnamide) is preferred.

  Examples of the hindered amine stabilizer include known hindered amine compounds having a 2,2,6,6-tetramethylpiperidine skeleton. Specific examples of hindered amine compounds include 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-2,2 , 6,6-tetramethylpiperidine, 4-phenylacetoxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-methoxy-2,2 , 6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2, 2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4-ethylcarba Yloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexylcarbamoyloxy-2,2,6,6-tetramethylpiperidine, 4-phenylcarbamoyloxy-2,2,6,6-tetramethylpiperidine, Bis (2,2,6,6-tetramethyl-4-piperidyl) carbonate, bis (2,2,6,6-tetramethyl-4-piperidyl) oxalate, bis (2,2,6,6-tetramethyl) -4-piperidyl) malonate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) adipate, bis (2,2 , 6,6-tetramethyl-4-piperidyl) terephthalate, 1,2-bis (2,2,6,6-tetramethyl-4-piperidyloxy) eta , Α, α′-bis (2,2,6,6-tetramethyl-4-piperidyloxy) -p-xylene, bis (2,2,6,6-tetramethyl-4-piperidyltolylene) -2 , 4-dicarbamate, bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylene-1,6-dicarbamate, tris (2,2,6,6-tetramethyl-4-piperidyl) -Benzene-1,3,5-tricarboxylate, tris (2,2,6,6-tetramethyl-4-piperidyl) -benzene-1,3,4-tricarboxylate, 1- [2- {3 -(3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy} butyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] 2,2 , 6,6-tetramethyl Piperidine, 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and β, β, β ′, β ′,-tetramethyl-3,9- [ 2,4,8,10-tetraoxaspiro (5,5) undecane] condensate with diethanol, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6, -succinate Examples include polycondensates of tetramethylpiperidine, 1,3-benzenedicarboxamide-N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) and the like.

  As a product of a hindered amine compound, products manufactured by ADEKA “ADK STAB LA-52, LA-57, LA-62, LA-67, LA-63P, LA-68LD, LA-77, LA-82, LA-87” "Products manufactured by Ciba Specialty Chemicals Co., Ltd." Tinubin 622,944,119,770,144 ", products manufactured by Sumitomo Chemical Co., Ltd." Sumisorb 577 ", products manufactured by Cyamide Co., Ltd. And “Nairostav S-EED” manufactured by Clariant Japan.

  Examples of the organic sulfur stabilizer include didodecylthiodipropionate, ditetradecylthiodipropionate, dioctadecylthiodipropionate, pentaerythritol tetrakis (3-dodecylthiopropionate), and thiobis (N-phenyl). -Β-naphthylamine) and other organic thioacid compounds, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, mercaptobenzimidazole compounds such as metal salts of 2-mercaptobenzimidazole, diethyldithiocarbamine Dithiocarbamate compounds such as metal salts of acids and metal salts of dibutyldithiocarbamate, and thioureas such as 1,3-bis (dimethylaminopropyl) -2-thiourea and tributylthiourea Compounds, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, nickel dibutyldithiocarbamate, nickel isopropyl xanthate include trilauryl trithiophosphite and the like.

Among these, mercaptobenzimidazole compounds, dithiocarbamic acid compounds, thiourea compounds, and organic thioacid compounds are preferable, and mercaptobenzimidazole compounds and organic thioacid compounds are more preferable. In particular, a thioether-based compound having a thioether structure can be suitably used because it receives oxygen from an oxidized substance and reduces it. Specifically, 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, ditetradecylthiodipropionate, dioctadecylthiodipropionate, pentaerythritol tetrakis (3-dodecylthiopropionate) are more preferable. Tetradecylthiodipropionate, pentaerythritol tetrakis (3-dodecylthiopropionate) and 2-mercaptomethylbenzimidazole are more preferred, and pentaerythritol tetrakis (3-dodecylthiopropionate) is particularly preferred.
The molecular weight of the organic sulfur compound is usually 200 or more, preferably 500 or more, and the upper limit is usually 3,000.

  As the oxalic anilide stabilizer, 4,4′-dioctyloxyoxanilide, 2,2′-diethoxyoxanilide, 2,2′-dioctyloxy-5,5′-di- Tributoxanilide, 2,2′-didodecyloxy-5,5′-di-tert-butoxanilide, 2-ethoxy-2′-ethyloxanilide, N, N′-bis (3-dimethylaminopropyl) oxanilide, 2-ethoxy-5-tert-butyl-2′-ethoxanilide and its mixture with 2-ethoxy-2′-ethyl-5,4′-di-tert-butoxanilide, o- and p-methoxy-disubstituted oxanilides Mixtures, o- and p-ethoxy-disubstituted oxanilide mixtures, and the like.

  As the aromatic secondary amine stabilizer, a compound having a diphenylamine skeleton, a compound having a phenylnaphthylamine skeleton, and a compound having a dinaphthylamine skeleton are preferable, and a compound having a diphenylamine skeleton and a compound having a phenylnaphthylamine skeleton are more preferable. . Specifically, p, p′-dialkyldiphenylamine (the alkyl group has 8 to 14 carbon atoms), octylated diphenylamine, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine, p- (p-toluene) Sulfonylamido) diphenylamine, N, N′-diphenyl-p-phenylenediamine, N-phenyl-N′-isopropyl-p-phenylenediamine, N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylene Compounds having a diphenylamine skeleton such as diamine and N-phenyl-N ′-(3-methacryloyloxy-2-hydroxypropyl) -p-phenylenediamine, N-phenyl-1-naphthylamine and N, N′-di-2- Compounds having a phenylnaphthylamine skeleton such as naphthyl-p-phenylenediamine And compounds having a dinaphthylamine skeleton such as 2,2'-dinaphthylamine, 1,2'-dinaphthylamine, and 1,1'-dinaphthylamine. Among these, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine, N, N′-di-2-naphthyl-p-phenylenediamine and N, N′-diphenyl-p-phenylenediamine are more preferable, N, N′-di-2-naphthyl-p-phenylenediamine and 4,4′-bis (α, α-dimethylbenzyl) diphenylamine are particularly preferred.

As the inorganic stabilizer, a copper compound and a halide are preferable.
The copper compound is a copper salt of various inorganic acids or organic acids, and excludes halides described later. The copper may be either cuprous or cupric. Specific examples of the copper salt include copper chloride, copper bromide, copper iodide, copper phosphate, copper stearate, hydrotalcite, and styhite. And natural minerals such as pyrolite.

  Examples of the halide used as the inorganic stabilizer include, for example, alkali metal or alkaline earth metal halides; ammonium halides and quaternary ammonium halides of organic compounds; alkyl halides, allyl halides. Specific examples thereof include ammonium iodide, stearyltriethylammonium bromide, benzyltriethylammonium iodide, and the like. Among these, alkali metal halide salts such as potassium chloride, sodium chloride, potassium bromide, potassium iodide, sodium iodide and the like are preferable.

  The combined use of a copper compound and a halide, in particular, the combined use of a copper compound and a halogenated alkali metal salt is preferable because it exhibits excellent effects in terms of heat discoloration resistance and weather resistance (light resistance). For example, when a copper compound is used alone, the molded product may be colored reddish brown by copper, and this coloring is not preferable depending on the application. In this case, discoloration to reddish brown can be prevented by using a copper compound and a halide together.

In the present invention, among the above stabilizers, in particular, from the viewpoint of processing stability at the time of melt molding, heat aging resistance, appearance of molded products, and prevention of coloring, organic sulfur, aromatic secondary amine, and inorganic The stabilizers are particularly preferred.
Content of these stabilizers is 0.01-1 mass part normally with respect to 100 mass parts of polyamide resins, Preferably it is 0.01-0.8 mass part.

  Moreover, it is also preferable to mix | blend an inorganic filler with the polyamide resin of this invention, unless the objective of this invention is impaired, and a glass-type filler (glass fiber, a grinding | pulverized glass fiber (milled fiber), glass flakes, glass) Bead, etc.), calcium silicate filler (wollastonite, etc.), mica, talc, kaolin, potassium titanate whisker, boron nitride, carbon fiber, etc., and two or more of these may be used in combination.

  Molded products obtained by using the polyamide resin of the present invention include various films, sheets, laminated films, laminated sheets, tubes, hoses, pipes, modified extrusions, hollow containers, bottles, fibers, various shaped parts, etc. A molded product can be given.

  Molded products obtained using the polyamide resin of the present invention can be used for molded parts for various applications that require heat resistance and moldability, such as parts for electric and electronic equipment, parts for transportation equipment such as automobiles, general machine parts, precision parts. Examples include mechanical parts, and particularly suitable for LED reflectors, LED mounting substrates, heat dissipation members, and the like.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not construed as being limited to the following examples / comparative examples.

Example 1
A sebacic acid (product name: Sebacic acid, manufactured by Ito Oil Co., Ltd.) precisely weighed in a reaction vessel with an internal volume of 50 liters equipped with a stirrer, a partial condenser, a cooler, a thermometer, a dropping device and a nitrogen introduction tube, and a strand die TA) 8950 g (44.25 mol), calcium hypophosphite 12.54 g (0.074 mol), and sodium acetate 6.45 g (0.079 mol) were weighed and charged. After sufficiently purging the inside of the reaction vessel with nitrogen, the pressure was increased to 0.4 MPa with nitrogen, the temperature was raised from 20 ° C. to 190 ° C. with stirring, and sebacic acid was uniformly melted in 55 minutes. Then, 5960 g (43.76 mol) of paraxylylenediamine (Mitsubishi Gas Chemical Co., Ltd.) was added dropwise over 110 minutes with stirring. During this time, the internal temperature of the reaction vessel was continuously increased to 293 ° C. In the dropping step, the pressure was controlled to 0.4 MPa, and the generated water was removed from the system through a partial condenser and a cooler. The temperature of the partial condenser was controlled in the range of 145 to 147 ° C. After completion of dropwise addition of paraxylylenediamine, the polycondensation reaction was continued for 20 minutes at a reaction vessel pressure of 0.4 MPa. During this time, the temperature inside the reaction vessel was raised to 296 ° C. Thereafter, the internal pressure of the reaction vessel was reduced from 0.4 MPa to 0.12 MPa over 30 minutes. During this time, the internal temperature rose to 298 ° C. Thereafter, the pressure was reduced at a rate of 0.002 MPa / minute, and the pressure was reduced to 0.08 MPa over 20 minutes. The temperature in the reaction vessel at the time of completion of decompression was 301 ° C. Thereafter, the inside of the system was pressurized with nitrogen, the temperature in the reaction vessel was 301 ° C., the resin temperature was 301 ° C., the polymer was taken out from the strand die into a strand shape, cooled with 20 ° C. cooling water, pelletized, and about 13 kg. A polyamide resin was obtained. The cooling time in cooling water was 5 seconds, and the strand take-up speed was 100 m / min.

Melting point (Tm), glass transition temperature (Tg), number average molecular weight (Mn), molecular weight distribution (Mw / Mn), reaction molar ratio (r), terminal amino group concentration ([NH ₂ ]), terminal of this polyamide resin The carboxyl group concentration ([COOH]) and its ratio ([NH ₂ ] / [COOH]) and the 5% weight loss temperature were as shown in Table 2.

In addition, these evaluation methods are as follows.
(1) Melting point (Tm) and glass transition temperature (Tg):
By a differential scanning calorimetry (DSC) method, using a DSC-60 manufactured by Shimadzu Corporation, the temperature was raised from 30 ° C. to a temperature not lower than the expected melting point at a rate of 10 ° C./min to melt the polyamide resin. The temperature at the peak top of the endothermic peak at this time was defined as the melting point. After melting, the sample was cooled with dry ice, then heated to a temperature above the melting point at a rate of 10 ° C./min, and the glass transition point was determined.

(2) Number average molecular weight (Mn):
The terminal amino group concentration [NH ₂ ] (μ equivalent / g) and the terminal carboxyl group concentration [COOH] (μ equivalent / g) of the polyamide resin were determined by the neutralization titration described below and calculated by the following equation.
Number average molecular weight = 2,000,000 / ([COOH] + [NH ₂ ])

(3) Molecular weight distribution (Mw / Mn):
Using "HLC-8320GPC" manufactured by Tosoh Corporation as the apparatus and two "TSK gel Super HM-H" manufactured by Tosoh Corporation as the column, eluent hexafluoroisopropanol (HFIP) having a sodium trifluoroacetate concentration of 10 mmol / l, resin The measurement was performed under the conditions of a concentration of 0.02% by mass, a column temperature of 40 ° C., a flow rate of 0.3 ml / min, and a refractive index detector (RI), and obtained as a standard polymethyl methacrylate conversion value.

(4) Reaction molar ratio (r):
It calculated | required by the above-mentioned next formula.
r = (1-cN-b (CN)) / (1-cC + a (CN))
Where
a: M1 / 2
b: M2 / 2
c: 18.015
M1: Molecular weight of diamine (g / mol)
M2: Molecular weight of dicarboxylic acid (g / mol)
N: Terminal amino group concentration (equivalent / g)
C: Terminal carboxyl group concentration (equivalent / g)

(5) Terminal amino group concentration ([NH ₂ ]):
0.5 g of polyamide resin was precisely weighed, dissolved in 30 ml of a phenol / methanol (4: 1) mixed solution at 20 to 30 ° C. with stirring, completely dissolved, and then neutralized and titrated with 0.01 N hydrochloric acid.
(6) Terminal carboxyl group concentration ([COOH]):
0.1 g of polyamide resin is precisely weighed and dissolved in 30 ml of benzyl alcohol with stirring and dissolving at 200 ° C. for about 15 minutes in a nitrogen stream for about 15 minutes. Add 1 ml. The solution was kept at 160 to 165 ° C. and titrated with a titrant (0.01 mol / l as KOH) in which 0.132 g of KOH was dissolved in 200 ml of benzyl alcohol, and the color of the solution changed from yellow to red. It was determined by setting the end point when there was no change.
(7) Terminal amino group concentration / terminal carboxyl group concentration ([NH ₂ ] / [COOH]):
Calculated from each of the above concentrations.

(8) Thermal stability of resin during molding (heat resistance)
Using the obtained polyamide resin pellets, the temperature was increased from 30 ° C. to 500 ° C. at a rate of 10 ° C./minute in a DTG-60 manufactured by Shimadzu Corporation by thermogravimetry (TG), The temperature at which 5% weight loss was confirmed from the weight at the time of ° C. was determined. It can be said that the higher the 5% weight loss temperature is, the more the degradation degradation of the resin is suppressed. It can be said that this is a resin excellent in heat resistance and molding processability, in which adhesion of decomposition products is suppressed.

(Examples 2 and 3)
In Example 1, except that the amount of paraxylylenediamine added was 6026 g (44.25 mol), the resin temperature at the time of strand withdrawal, the strand cooling conditions, and the strand take-up speed were changed to the conditions shown in Table 1, A polyamide resin was obtained in the same manner as in Example 1.
The evaluation results of the obtained polyamide resin are shown in Table 2.

Example 4
In Example 1 above, the amount of paraxylylenediamine dropped was 5900 g (43.32 mol), and the resin temperature, strand cooling conditions, and strand take-up speed at the time of strand withdrawal were changed to the conditions shown in Table 1 A polyamide resin was obtained in the same manner as in Example 1.
The evaluation results of the obtained polyamide resin are shown in Table 2.

(Example 5)
Sebacic acid (Ito Oil Co., Ltd.) was placed in a 50 liter stainless steel reaction tank with an oil jacket equipped with a partial condenser, total condenser, stirrer, nitrogen gas inlet tube and diamine dropping port through which temperature-controlled oil circulates. Product name: 8950 g (44.25 mol), product name: Sebacic acid TA), calcium hypophosphite 12.54 g (0.074 mol), sodium acetate 6.45 g (0.079 mol), paraxylylenediamine (Mitsubishi Gas Chemical Co., Ltd.) ) 5960 g (43.76 mol) and 19 kg of distilled water were added, and the atmosphere was sufficiently replaced with nitrogen.
A salt composed of sebacic acid and paraxylylenediamine was produced while heating the temperature to 200 ° C. over 1.5 hours while stirring the contents while the apparatus was sealed. Thereafter, the temperature was further raised, and when the internal pressure of the reaction vessel reached 1.9 MPa, while maintaining the pressure, the charged water and the reaction product water were distilled out of the apparatus over 1.5 hours. The temperature was raised to. Subsequently, while distilling off water, the reaction pressure was lowered to normal pressure in 1 hour, and the reaction temperature was raised to 302 ° C. during that time. Thereafter, the internal pressure of the reaction system was continuously reduced to 0.08 MPa over 10 minutes, and then the reaction was continued for 5 minutes. At a resin temperature of 302 ° C., the polymer was taken out from the strand die in a strand shape, cooled with 20 ° C. cooling water, and pelletized to obtain a polyamide resin. The cooling time in cooling water was 5 seconds, and the strand take-up speed was 100 m / min.
The evaluation results of the obtained polyamide resin are shown in Table 2.

(Comparative Example 1)
In Example 1 above, a polyamide resin was obtained in the same manner as in Example 1 except that the strand was cooled on the net belt by air cooling for the cooling time shown in Table 1. The obtained polyamide resin had a single endothermic peak.
The evaluation results of the obtained polyamide resin are shown in Table 2.

(Comparative Example 2)
In Example 4 above, a polyamide resin was obtained in the same manner as in Example 1 except that the strands were cooled on the net belt by air cooling for the cooling time shown in Table 1. The obtained polyamide resin had a single endothermic peak.
The evaluation results of the obtained polyamide resin are shown in Table 2.

(Comparative Example 3)
In Example 1 above, a polyamide resin was obtained in the same manner as in Example 1 except that the resin temperature at the time of strand withdrawal, the strand cooling conditions, and the strand take-up speed were changed to the conditions shown in Table 1. The obtained polyamide resin had a single endothermic peak.
The evaluation results of the obtained polyamide resin are shown in Table 2.

(Comparative Example 4)
In Example 1 above, a polyamide resin was obtained in the same manner as in Example 1 except that the resin temperature at the time of strand withdrawal, the strand cooling conditions, and the strand take-up speed were changed to the conditions shown in Table 1. The obtained polyamide resin had a single endothermic peak.
The evaluation results of the obtained polyamide resin are shown in Table 2.

(Comparative Example 5)
In Example 1 above, the polyamide resin was produced in the same manner as in Example 1 except that the resin temperature at the time of strand extraction, the strand cooling conditions, and the strand take-up speed were changed to the conditions shown in Table 1. The strands might wind around the cutter during pelletizing, resulting in poor productivity.

  From the results in Table 2, it can be seen that the polyamide resin of the present invention has a high 5% weight loss temperature by the TG method and is excellent in heat resistance and molding processability (Examples 1 to 5). On the other hand, it can be seen that the polyamide resins of Comparative Examples 1 to 4 having no plurality of melting points have a low 5% weight reduction temperature by the TG method and are inferior in heat resistance and molding processability.

  Since the polyamide resin of the present invention is a polyamide resin having high heat resistance and excellent moldability, parts for electric and electronic devices, transportation equipment parts such as automobiles, general machinery that require heat resistance and moldability It can be widely used in the field of various molded parts such as parts and precision machine parts, and has very high industrial applicability.

Claims (6)

70 mol% or more of diamine structural units are derived from xylylenediamine units, and 50 mol% or more of dicarboxylic acid structural units are polyamide resins derived from sebacic acid,
The xylylenediamine unit contains 50-100 mol% paraxylylenediamine-derived units, 0-50 mol% metaxylylenediamine-derived units,
The number average molecular weight (Mn) is 6,000～30,000, a method for producing a polyamide resin having two or more melting point within the temperature range of two hundred and seventy to three hundred and ten ° C.,
The temperature range of the melting point to the melting point + 20 ° C. from the peak top temperature of the peak on the highest temperature side of the endothermic peak at the time of temperature rise observed from the polyamide resin by the differential scanning calorimetry of the polyamide resin. A step of extracting in a strand shape,
Including a step of cooling the extracted strand-like polyamide resin in 0 to 60 ° C. cooling water ,
When the polyamide resin is extracted from the polymerization reaction vessel into a strand, the strand extraction speed is 100 to 300 m / min.
A method for producing a polyamide resin, wherein when the strand-like polyamide resin extracted from the polymerization reaction vessel is cooled, the time during which the strand-like polyamide resin comes into contact with cooling water is 2 to 60 seconds . As a pre-process of the process of extracting the polyamide resin from the polymerization reaction vessel into a strand shape,
Step of melting dicarboxylic acid, step of continuously dropping diamine into molten dicarboxylic acid, after end of diamine dropping, among endothermic peaks at the time of temperature rise observed by differential scanning calorimetry of polyamide resin, step of holding 0-60 minutes at a melting point ~ the melting point + 30 ° C. which is the temperature of peak top of the peak, further polyamide resin according to claim 1, characterized in that it comprises a step of continuing the polycondensation reaction under negative pressure Manufacturing method. As a pre-process of the process of extracting the polyamide resin into a strand shape,
Among the endothermic peaks observed during the step of melting and holding a salt of dicarboxylic acid and diamine under pressure, the step of raising the temperature while reducing the pressure, and the differential scanning calorimetry of the polyamide resin, the peak on the highest temperature side 2. The method for producing a polyamide resin according to claim 1, further comprising a step of holding at 0 to 60 minutes at a melting point which is a peak top temperature of the above-mentioned melting point + 30 ° C. for 0 to 60 minutes. The method for producing a polyamide resin according to claim 1, wherein the polyamide resin has a molecular weight distribution (Mw / Mn) of 2.1 to 3.1. The molar ratio of the reacted diamine unit to the reacted dicarboxylic acid unit of the polyamide resin (mole number of reacted diamine unit / mole number of reacted dicarboxylic acid unit) is 0.97 to 1.02. The manufacturing method of the polyamide resin in any one of Claims 1-4. The method for producing a polyamide resin according to any one of claims 1 to 5, wherein the dicarboxylic acid component other than the sebacic acid is selected from α, ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms.