JP2015071706A - Method for producing polyamide resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing a polyamide resin having a desired relatively high molecular weight using sebacic acid as a dicarboxylic acid.SOLUTION: There is provided a method for producing a polyamide resin which contains a diamine unit and a dicarboxylic acid unit containing 50 mol% or more of a sebacic acid unit and has a desired number average molecular weight by a polymerization reaction using a diamine and a dicarboxylic acid containing sebacic acid containing more than 0 mol% and less than 6 mol% of a monocarboxylic acid, wherein a polycondensation reaction is performed by controlling feed amounts of the dicarboxylic acid and the diamine so that a feed molar ratio α of the dicarboxylic acid and the diamine calculated to obtain a polyamide resin having the desired number average molecular weight is achieved at a predetermined conversion Por Pof an amino group or a carboxylic group when using sebacic acid containing β mol% of monocarboxylic acid.

Description

  The present invention relates to a method for producing a polyamide resin, and more particularly to a method for producing a polyamide resin using sebacic acid as a dicarboxylic acid.

Polyamide resins typified by nylon 6, nylon 66, etc. are used in various applications such as clothing fibers and engineering plastics because of excellent properties such as toughness, chemical resistance and electrical properties, and ease of melt molding. Has been.
In recent years, attention has been given to polyamide resins obtained using sebacic acid as a dicarboxylic acid (see Patent Documents 1 to 3). This polyamide resin has characteristics such as low water absorption and excellent dimensional stability, and is expected to be applied to uses such as electrical and electronic parts. Moreover, since sebacic acid is a plant-derived raw material obtained from castor oil, it attracts attention from the viewpoint of environmental conservation.
Sebacic acid is usually available in a purity of 97-99.5%.

JP 2013-87369 A JP 2011-57930 A JP 2010-253803 A

  In the case of polymerizing a polyamide resin using sebacic acid as a dicarboxylic acid, there is a case where the degree of polymerization is not sufficiently increased and a polyamide resin having a desired molecular weight cannot be produced. This is particularly noticeable when trying to increase the molecular weight by solid phase polymerization.

  An object of the present invention is to provide a method for efficiently producing a desired relatively high molecular weight polyamide resin in polymerization of a polyamide resin using sebacic acid as a dicarboxylic acid.

  As a result of intensive studies, the present inventors have found that a small amount of monocarboxylic acid contained in sebacic acid disturbs the molar balance of diamine and dicarboxylic acid in the polymerization reaction of polyamide, and cannot be ignored in the polymerization reaction. Found that is giving. By determining the molar ratio of diamine and dicarboxylic acid in consideration of the monocarboxylic acid content, the molecular weight of the polyamide resin can be controlled, and the desired relatively high molecular weight polyamide resin can be efficiently produced. I found it. The present invention has been completed based on such findings.

The present invention relates to the following polyamide resin production method and polyamide resin molecular weight control method.
<1> A diamine unit and a dicarboxylic acid containing sebacic acid containing more than 0 mol% and less than 6 mol% of a monocarboxylic acid are used to carry out a polymerization reaction, whereby 50 mol% or more of diamine units and sebacic acid units are obtained. A method for producing a polyamide resin containing a dicarboxylic acid unit and having a desired number average molecular weight,
Based on the following formula (A) or (B), the desired amino acid or carboxyl group reaction rate P _A or P _C when using sebacic acid containing β mol% monocarboxylic acid is used. Obtaining the charged molar ratio α of diamine and dicarboxylic acid to obtain a polyamide resin having a number average molecular weight Mn,
A process for producing a polyamide resin, wherein a polycondensation reaction is carried out by controlling the amounts of dicarboxylic acid and diamine charged so as to satisfy the required α.
Mn = 2 [(α (2 -β / 100) (M 3/2-M 4 P A) - (M 1 -M 2) (β / 100) + M 1)] / (2-α (2-β / 100) (2P _A -1)) (A)
Mn = 2 [(α (2 -β / 100) (M 3/2) - (M 1 -M 2 -M 4 P C) (β / 100) + M 1 -2M 4 P C)] / ((α -2P _C ) (2-β / 100) +2) (B)
(If the diamine involved in the polymerization reaction is less than or equal to the equivalent of the dicarboxylic acid involved in the polymerization reaction, the formula (A) is applied, and the diamine involved in the polymerization reaction is equivalent to the dicarboxylic acid involved in the polymerization reaction. In the case of exceeding, the formula (B) is applied.
In the formulas (A) and (B), β represents the content of the monocarboxylic acid contained in the dicarboxylic acid, and is more than 0 mol% and less than 6 mol%. M ₁ represents the molecular weight of the dicarboxylic acid involved in the polymerization reaction, M ₂ represents the molecular weight of the monocarboxylic acid contained in the dicarboxylic acid, M ₃ represents the molecular weight of the diamine involved in the polymerization reaction, M ₄ represents the molecular weight of water, P _a represents the reaction rate of the amino group, P _C represents the reaction rate of the carboxyl group. )
α = 2X / (2Y− (β / 100) Y) (1)
(In the formula, X represents the number of moles (mol) of the charged diamine, Y represents the number of moles (mol) of the charged dicarboxylic acid, and β represents the content of the monocarboxylic acid contained in the dicarboxylic acid. , More than 0 mol% and less than 6 mol%.)
<2> The method for producing a polyamide resin according to <1>, wherein the number average molecular weight Mn is 10,000 to 50,000.
<3> the reaction rate P _A or P _C is determined from the polyamide obtained using the sebacic acid which does not contain monocarboxylic acid, method for producing the polyamide resin according to <1> or <2>.
<4> The method for producing a polyamide resin according to any one of <1> to <3>, wherein the diamine is continuously added to the dicarboxylic acid in a molten state and polycondensed under normal pressure or under pressure.
<5> The method for producing a polyamide resin according to <4>, wherein the molten dicarboxylic acid is filtered before being introduced into the reaction vessel.
<6> The method for producing a polyamide resin according to any one of <1> to <5>, wherein 70 mol% or more of the diamine unit is derived from xylylenediamine and / or bis (aminomethyl) cyclohexane.
<7> The method for producing a polyamide resin according to <6>, wherein the xylylenediamine is metaxylylenediamine, paraxylylenediamine, or a mixture thereof.
<8> The polyamide resin according to <6>, wherein the bis (aminomethyl) cyclohexane is 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane or a mixture thereof. Production method.
<9> The method for producing a polyamide resin according to any one of <1> to <8>, wherein all the dicarboxylic acid units are derived from sebacic acid.
When performing a polymerization reaction using <10> diamine and dicarboxylic acid containing sebacic acid containing more than 0 mol% and less than 6 mol% monocarboxylic acid, the diamine unit and sebacic acid unit are 50 mol% or more. A method for controlling the number average molecular weight Mn of a polyamide resin containing a dicarboxylic acid unit comprising:
Based on the following equation (A) or (B), when the monocarboxylic acid with sebacic acid containing β mol%, the reaction rate P _A or P _C of a predetermined amino or carboxyl group, the objective Obtaining the charged molar ratio α of diamine and dicarboxylic acid to obtain a polyamide resin having a number average molecular weight Mn,
A method for controlling the molecular weight of a polyamide resin, in which a polycondensation reaction is performed by adjusting the charged amounts of dicarboxylic acid and diamine based on the following formula (1) so as to obtain the required α.
Mn = 2 [(α (2 -β / 100) (M 3/2-M 4 P A) - (M 1 -M 2) (β / 100) + M 1)] / (2-α (2-β / 100) (2P _A -1)) (A)
Mn = 2 [(α (2 -β / 100) (M 3/2) - (M 1 -M 2 -M 4 P C) (β / 100) + M 1 -2M 4 P C)] / ((α -2P _C ) (2-β / 100) +2) (B)
(If the diamine involved in the polymerization reaction is less than or equal to the equivalent of the dicarboxylic acid involved in the polymerization reaction, the formula (A) is applied, and the diamine involved in the polymerization reaction is equivalent to the dicarboxylic acid involved in the polymerization reaction. In the case of exceeding, the formula (B) is applied.
In the formulas (A) and (B), β represents the content of the monocarboxylic acid contained in the dicarboxylic acid, and is more than 0 mol% and less than 6 mol%. M ₁ represents the molecular weight of the dicarboxylic acid involved in the polymerization reaction, M ₂ represents the molecular weight of the monocarboxylic acid contained in the dicarboxylic acid, M ₃ represents the molecular weight of the diamine involved in the polymerization reaction, M ₄ represents the molecular weight of water, P _a represents the reaction rate of the amino group, P _C represents the reaction rate of the carboxyl group. )
α = 2X / (2Y− (β / 100) Y) (1)
(In the formula, X represents the number of moles (mol) of the charged diamine, Y represents the number of moles (mol) of the charged dicarboxylic acid, and β represents the content of the monocarboxylic acid contained in the dicarboxylic acid. , More than 0 mol% and less than 6 mol%.)

  According to the method of the present invention, it is possible to efficiently produce a desired relatively high molecular weight polyamide resin having a number average molecular weight in the range of about 10,000 to 50,000 using sebacic acid as a dicarboxylic acid. In particular, according to the method of the present invention, it is possible to efficiently produce a polyamide resin controlled to a desired molecular weight even if inexpensive sebacic acid with low purity is used.

FIG. 1 shows the content of monocarboxylic acid contained in sebacic acid β mol% calculated based on the formula (A) or (B) when the reaction rate of amino group or carboxyl group is 1.000. FIG. 3 is a graph showing the relationship between the charge molar ratio α of diamine and dicarboxylic acid for obtaining a polyamide resin having a number average molecular weight Mn of 10,000, 20000 or 50000.

  The present invention performs a polymerization reaction using a diamine and a dicarboxylic acid containing sebacic acid containing more than 0 mol% and less than 6 mol% of a monocarboxylic acid, whereby 50 mol% of diamine units and sebacic acid units are obtained. A method for producing a polyamide resin having a dicarboxylic acid unit and having a desired number average molecular weight, and is involved in a polymerization reaction in consideration of the content of a monocarboxylic acid contained in the dicarboxylic acid. The polycondensation reaction is carried out by controlling the amount of dicarboxylic acid and diamine charged. That is, when performing the above polymerization reaction, considering the content of monocarboxylic acid contained in the dicarboxylic acid, by adjusting the amount of dicarboxylic acid and diamine involved in the polymerization reaction, the desired number average In this method, the molecular weight of the polyamide resin is controlled so as to have a molecular weight Mn. Here, the diamine unit means a structural unit of a polyamide resin derived from diamine, and the dicarboxylic acid unit means a structural unit of a polyamide resin derived from dicarboxylic acid.

(Dicarboxylic acid)
From the viewpoint of producing a polyamide resin having low water absorption and excellent dimensional stability, the dicarboxylic acid used in the present invention is 50 mol% or more, preferably 70 mol% or more, of sebacic acid in 100 mol% of the dicarboxylic acid. Preferably it is 90 mol% or more, More preferably, it contains substantially 100 mol%. Since sebacic acid is a plant-derived raw material obtained from castor oil, it has attracted attention from the viewpoint of environmental conservation.

  The dicarboxylic acid used in the present invention may contain a dicarboxylic acid other than sebacic acid depending on purposes such as mechanical properties, molding processability, and heat resistance of the resulting polyamide. Examples of such dicarboxylic acids include, but are not limited to, linear aliphatic dicarboxylic acids other than sebacic acid, branched aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, or mixtures thereof. It is not a thing.

Examples of linear aliphatic dicarboxylic acids other than sebacic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecane Examples include diacid, pentadecanedioic acid, hexadecanedioic acid and the like. Among these, a straight-chain aliphatic dicarboxylic acid having 6 to 18 carbon atoms is preferable, at least one selected from the group consisting of adipic acid, azelaic acid, undecanedioic acid and dodecanedioic acid is more preferable, and adipic acid is particularly preferable.
Specific examples of the branched aliphatic dicarboxylic acid include 3,3-diethylsuccinic acid, 2-methyladipic acid, 2,2-dimethylglutaric acid, 2,4-dimethylglutaric acid, 3,3-dimethylglutaric acid, And trimethyladipic acid.
Specific examples of the alicyclic dicarboxylic acid include 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and the like.
Specific examples of the aromatic dicarboxylic acid include isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and the like. It is done.

(Diamine)
Examples of the diamine used in the present invention include, but are not limited to, aliphatic diamine, alicyclic diamine, aromatic diamine, or a mixture thereof.
Specific examples of the aliphatic diamine include 1,4-butanediamine, 1,6-hexanediamine, 1,8-octanediamine, 1,10-decanediamine, 1,12-dodecanediamine, 2-methyl-1, 5-pentanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine, 5-methyl- 1,9-nonanediamine and the like can be mentioned.
Specific examples of the alicyclic diamine include bis (aminomethyl) cyclohexane, cyclohexanediamine, methylcyclohexanediamine, and isophoronediamine. Examples of bis (aminomethyl) cyclohexane include 1,3-bis (aminomethyl) cyclohexane and 1,4-bis (aminomethyl) cyclohexane.
Specific examples of the aromatic diamine include xylylenediamine. Examples of xylylenediamine include metaxylylenediamine and paraxylylenediamine.

The diamine used in the present invention is appropriately selected according to the properties of the target polyamide.
For example, from the viewpoint of heat resistance of the obtained polyamide, 1,6-hexanediamine, 1,8-octanediamine, and 1,10-decanediamine are preferable. Among these, when considering environmental conservation, 1,10-decanediamine, which is a plant-derived raw material obtained from castor oil, is more preferable.
On the other hand, xylylenediamine and bis (aminomethyl) cyclohexane are preferred from the viewpoints of mechanical properties (strength, elastic modulus) and gas barrier properties of the obtained polyamide. In this case, in 100 mol% of the diamine, xylylenediamine and / or bis (aminomethyl) cyclohexane is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and still more preferably substantially. Contains 100 mol%.
The xylylenediamine is preferably metaxylylenediamine, paraxylylenediamine or a mixture thereof, more preferably metaxylylenediamine from the viewpoint of the gas barrier properties of the obtained polyamide, and the heat resistance and dimensions of the resulting polyamide. From the viewpoint of stability, paraxylylenediamine is more preferable.

(Feed molar ratio of diamine and dicarboxylic acid)
The sebacic acid used as the dicarboxylic acid is usually available in a purity of 97 to 99.5%. Conventionally, when polymerizing a polyamide resin using sebacic acid as a dicarboxylic acid, the degree of polymerization did not sufficiently increase, and a polyamide resin having a desired molecular weight could not be produced. It has been found that the molar balance of diamine and dicarboxylic acid in the polymerization reaction of polyamide is disturbed by a small amount of monocarboxylic acid contained in sebacic acid.
Therefore, in the method of the present invention, the polycondensation reaction is performed by controlling the amount of diamine and dicarboxylic acid charged in consideration of a small amount of monocarboxylic acid contained in sebacic acid. Specifically, first, based on the formula (A) or (B) described later, the reaction rate P _A of a predetermined amino group or carboxyl group when sebacic acid containing β mol% of a monocarboxylic acid is used. or at P _C, obtaining a molar ratio α of the diamine and dicarboxylic acid to obtain a polyamide resin having the desired number average molecular weight Mn. Next, a polycondensation reaction is performed by controlling the charged amounts of dicarboxylic acid and diamine based on the following formula (1) so as to obtain the obtained α.
α = 2X / (2Y− (β / 100) Y) (1)
(In the formula, X represents the number of moles (mol) of the charged diamine, Y represents the number of moles (mol) of the charged dicarboxylic acid, and β represents the content of the monocarboxylic acid contained in the dicarboxylic acid. , More than 0 mol% and less than 6 mol%.)

  The molecule in formula (1) means the number of amino groups involved in the polymerization reaction, and the denominator means the number of carboxyl groups involved in the polymerization reaction. Since 2 amino groups exist in 1 mol of diamine, when the diamine to be charged is X mol, the number of amino groups involved in the polymerization reaction is “2X”. On the other hand, since 2 carboxyl groups exist in 1 mol of dicarboxylic acid, when the charged dicarboxylic acid is Y mol, the number of carboxyl groups involved in the polymerization reaction is theoretically “2Y”. However, since the dicarboxylic acid contains β mol% of a monocarboxylic acid that inhibits the polymerization reaction, the monocarboxylic acid content “(β / 100) Y” contained in the Y mol of the dicarboxylic acid is polymerized. The number of carboxyl groups involved in the reaction is excluded from “2Y”, and the number of carboxyl groups actually involved in the polymerization reaction is “2Y− (β / 100) Y”. In the present invention, an industrially purified diamine having a high purity is used, and therefore impurities in the diamine can be ignored in terms of controlling the molecular weight of the polymerization reaction.

  Β representing the content of the monocarboxylic acid contained in the dicarboxylic acid is more than 0 mol% and less than 6 mol%. When β is 0 mol%, the molecular weight of the polyamide resin can be controlled without using the method of the present invention, and is excluded from the present invention. When β is 6 mol% or more, the amount of monocarboxylic acid that inhibits the polymerization reaction is too much, so that even if an attempt is made to increase the degree of polymerization, it does not increase sufficiently and a polyamide resin having a desired molecular weight cannot be produced.

Β in the present invention is preferably more than 0 mol% and 2.6 mol% or less. Within the above range, the charged molar ratio α of diamine and dicarboxylic acid when no monocarboxylic acid is contained in the dicarboxylic acid (when β is 0 mol%) exceeds 0.970 and is 0.987 or less. A polyamide resin having a molecular weight equivalent to that of the polyamide resin obtained at 013 or more and less than 1.030 can be produced.
Further, β in the present invention is more preferably more than 0 mol% and not more than 1.0 mol%. Within the above range, the charge molar ratio α of diamine and dicarboxylic acid when no monocarboxylic acid is contained in the dicarboxylic acid (when β is 0 mol%) exceeds 0.970 and is less than 0.995. A polyamide resin having a molecular weight equivalent to that of the polyamide resin obtained when the ratio is 005 or more and less than 1.030 can be produced.
Further, β in the present invention is more preferably more than 0 mol% and 0.3 mol% or less. If it is in the said range, when the monocarboxylic acid is not contained in the dicarboxylic acid (when β is 0 mol%), the charged molar ratio α of the diamine and the dicarboxylic acid exceeds 0.970 and is 0.9985 or less. A polyamide resin having a molecular weight equivalent to that of the polyamide resin obtained when it is 0015 or more and less than 1.030 can be produced.

  The content β (mol%) of the monocarboxylic acid in the dicarboxylic acid is measured by gas chromatography. At this time, in order to improve the detection sensitivity, it is preferable to subject the whole amount of the dicarboxylic acid and monocarboxylic acid in the dicarboxylic acid to methyl esterification, and then subject to gas chromatography.

(Number average molecular weight Mn of polyamide resin)
The number average molecular weight Mn of the polyamide resin obtained by the method of the present invention is preferably in the range of 10,000 to 50,000, more preferably in the range of 12,000 to 40,000, and 14,000. More preferably, it is in the range of ˜30,000. By setting Mn within the above range, the mechanical strength in the case of a molded product is stabilized, and the mold has a suitable melt viscosity that provides good workability in terms of moldability. The number average molecular weight of the polyamide resin is measured by gel permeation chromatography (GPC).

The number average molecular weight Mn of the polyamide resin obtained by the method of the present invention is the α represented by the formula (1), the content β (mol%) of the monocarboxylic acid in the dicarboxylic acid, and the reaction of the amino group or carboxyl group. it can be controlled based on the ratio P _a or P _C. The number average molecular weight of the polyamide resin can be increased to some extent by increasing the polymerization time, but the resin may be deteriorated during the polymerization or the productivity may be lowered. On the other hand, according to the method of the present invention, a polyamide resin having a desired molecular weight can be efficiently produced by adjusting the raw material balance without excessively increasing the polymerization time in order to increase the molecular weight. .
Incidentally, the reaction rate P _A or P _C may be determined from the polyamide obtained using the sebacic acid which does not contain monocarboxylic acid, it can be appropriately set by the polymerization conditions such as polymerization temperature and polymerization time.

The number average molecular weight Mn of the polyamide resin is determined based on the following formula (A) or (B), and is preferably determined in the range of 10,000 ≦ Mn ≦ 50000.
Mn = 2 [(α (2 -β / 100) (M 3/2-M 4 P A) - (M 1 -M 2) (β / 100) + M 1)] / (2-α (2-β / 100) (2P _A -1)) (A)
Mn = 2 [(α (2 -β / 100) (M 3/2) - (M 1 -M 2 -M 4 P C) (β / 100) + M 1 -2M 4 P C)] / ((α -2P _C ) (2-β / 100) +2) (B)
(Wherein M ₁ represents the molecular weight of the dicarboxylic acid involved in the polymerization reaction, M ₂ represents the molecular weight of the monocarboxylic acid contained in the dicarboxylic acid, and M ₃ represents the molecular weight of the diamine involved in the polymerization reaction. M ₄ represents the molecular weight of water, P _A represents the reaction rate of the amino group, and P _C represents the reaction rate of the carboxyl group.)

First, formula (A) will be described.
The total mass W (g) of the polyamide resin is (total mass of dicarboxylic acids involved in the polymerization reaction) + (total mass of monocarboxylic acids contained in the dicarboxylic acid) + (total mass of diamines involved in the polymerization reaction) − (Mass of condensed water).
When the diamine participating in the polymerization reaction is equal to or less than the equivalent of the dicarboxylic acid participating in the polymerization reaction, the total mass W of the polyamide resin is represented by the following formula (2).
W = M ₁ (1−β / 100) Y + M ₂ (β / 100) Y + M ₃ X−M ₄ (2XP _A ) (2)
(Wherein M ₁ represents the molecular weight of the dicarboxylic acid involved in the polymerization reaction, M ₂ represents the molecular weight of the monocarboxylic acid contained in the dicarboxylic acid, and M ₃ represents the molecular weight of the diamine involved in the polymerization reaction. represents, M ₄ is .X which indicates the molecular weight of the water, the Y and β are the same meaning as X, Y and β in equation (1) .P _a represents the reaction rate of the amino group.)
The total mass of the dicarboxylic acid involved in the polymerization reaction is represented by “M ₁ (1-β / 100) Y”, and the total mass of the monocarboxylic acid contained in the dicarboxylic acid is “M ₂ (β / 100) Y”. The total mass of the diamine expressed and involved in the polymerization reaction is represented by “M ₃ X”. As described above, in the present invention, the impurities in the diamine can be ignored, and the number of molecules of the diamine to be charged is treated as the number of molecules of the diamine involved in the polymerization reaction. Since the polycondensation reaction when the diamine involved in the polymerization reaction is less than or equal to the equivalent of the dicarboxylic acid involved in the polymerization reaction depends on the amount of diamine, the mass of the condensed water is represented by “M ₄ (2XP _A )”. The

The total number a (mol) of polymer terminals in the polyamide resin is represented by (number of terminal carboxyl groups) + (number of terminal alkyl groups derived from monocarboxylic acid) + (number of terminal amino groups).
When the diamine involved in the polymerization reaction is less than or equal to the equivalent of the dicarboxylic acid involved in the polymerization reaction, the total number a of the polymer ends is represented by the following formula (3).
a = {(2Y− (β / 100) Y) −2XP _A } + (β / 100) Y + 2X (1−P _A )
= X (2-4P _A ) + 2Y (3)
(Wherein, X, is Y and β have the same meanings as X, Y and β in equation (1), P _A has the same meaning as P _A in the formula (2).)
Since the polycondensation reaction when the diamine involved in the polymerization reaction is less than or equal to the equivalent of the dicarboxylic acid involved in the polymerization reaction depends on the amount of diamine, the number of terminal carboxyl groups is determined from the number of carboxyl groups in the dicarboxylic acid. This is a value obtained by subtracting the number of amino groups of “(2Y- (β / 100) Y) -2XP _A ”. The number of terminal alkyl groups derived from monocarboxylic acid is represented by “(β / 100) Y”. The number of terminal amino groups is the number of amino groups remaining without reacting with the carboxyl group, and is represented by “2X (1-P _A )”.

Here, the number average molecular weight Mn of the polyamide resin can be obtained by a terminal group quantification method and can be represented by the following formula (4).
Mn = W / (a / 2) Formula (4)
When the above formulas (2) and (3) are substituted into the formula (4) and the numerator and denominator are respectively divided by Y, the number average molecular weight Mn is represented by the following formula (5).
Mn = 2 [{M ₁ (1-β / 100) + M ₂ (β / 100) + (M ₃ −M ₄ (2P _A )) (X / Y)}] / {(2-4P _A ) (X / Y) +2} Expression (5)
Here, X / Y is expressed by the following expression (6) from the expressions (1).
X / Y = (α / 2) (2-β / 100) (6)
When the formula (6) is substituted into the formula (5), the number average molecular weight Mn when the diamine involved in the polymerization reaction is equal to or less than the equivalent of the dicarboxylic acid involved in the polymerization reaction is represented by the formula (A). The

Next, the formula (B) will be described.
As described above, the total mass W (g) of the polyamide resin is (total mass of dicarboxylic acid involved in the polymerization reaction) + (total mass of monocarboxylic acid contained in the dicarboxylic acid) + (total of diamines involved in the polymerization reaction). Total mass)-(mass of condensed water).
When the diamine participating in the polymerization reaction exceeds the equivalent of the dicarboxylic acid participating in the polymerization reaction, the total mass W of the polyamide resin is represented by the following formula (7).
W = M ₁ (1-β / 100) Y + M ₂ (β / 100) Y + M ₃ X-M ₄ (2-β / 100) YP _C (7)
(Wherein, M _1, M _2, M ₃ and M _4, the .X the same meaning as M _1, M _2, M ₃ and M ₄ in the formula (2), the Y and β in Equation (1) (It is synonymous with X, Y, and β. P _C represents the reaction rate of a carboxyl group.)
The total mass of the dicarboxylic acid involved in the polymerization reaction is represented by “M ₁ (1-β / 100) Y”, and the total mass of the monocarboxylic acid contained in the dicarboxylic acid is “M ₂ (β / 100) Y”. The total mass of the diamine expressed and involved in the polymerization reaction is represented by “M ₃ X”. Since the polycondensation reaction when the diamine involved in the polymerization reaction exceeds the equivalent of the dicarboxylic acid involved in the polymerization reaction depends on the amount of dicarboxylic acid, the mass of the condensed water is “M ₄ (2-β / 100) YP _C ".

Further, as described above, the total number a (mol) of polymer terminals in the polyamide resin is represented by (number of terminal carboxyl groups) + (number of terminal alkyl groups derived from monocarboxylic acid) + (number of terminal amino groups).
When the diamine involved in the polymerization reaction exceeds the equivalent of the dicarboxylic acid involved in the polymerization reaction, the total number a of the polymer terminals is represented by the following formula (8).
a = {(2- (β / 100)) Y (1-P _C )} + (β / 100) Y + (2X− (2- (β / 100)) YP _C )
= 2X + 2Y-2 (2- (β / 100)) YP _C (8)
(Wherein, X, is Y and β have the same meanings as X, Y and β in equation (1), P _C is synonymous with P _C in the equation (7).)
Since the polycondensation reaction when the diamine involved in the polymerization reaction exceeds the equivalent amount of the dicarboxylic acid involved in the polymerization reaction depends on the amount of dicarboxylic acid, the number of terminal amino groups is determined from the number of amino groups in the diamine. This is a value obtained by subtracting the number of carboxyl groups from “2X- (2- (β / 100)) YP _C ”. The number of terminal alkyl groups derived from monocarboxylic acid is represented by “(β / 100) Y”. The number of terminal carboxyl groups is the number of carboxyl groups remaining without reacting with the amino group, and is represented by “(2- (β / 100)) Y (1-P _C )”.

Here, as described above, the number average molecular weight Mn of the polyamide resin can be obtained by a terminal group quantification method and can be represented by the above formula (4).
When the above formulas (7) and (8) are substituted into the formula (4) and the numerator and the denominator are respectively divided by Y, the number average molecular weight Mn is represented by the following formula (9).
Mn = 2 [(M ₁ (1-β / 100) + M ₂ (β / 100) + M ₃ (X / Y) − (2-β / 100) M ₄ P _C )] / (2 (X / Y) + 2-2 (2- (β / 100)) P _C ) (9)
Here, as described above, since X / Y is represented by formula (6) from formulas (1), when formula (6) is substituted into formula (9), the diamine involved in the polymerization reaction is polymerized. The number average molecular weight Mn when exceeding the equivalent of the dicarboxylic acid involved in is represented by the above formula (B).

In the above formulas (A) and (B), when a plurality of dicarboxylic acids involved in the polymerization reaction are present, the number average molecular weight M ₁ ′ of the dicarboxylic acid is used instead of the molecular weight M ₁ of the dicarboxylic acid. That is, the number average molecular weight M ₁ ′ of the dicarboxylic acid is represented by the following formula.
M ₁ '= ΣM _An N _An

Similarly, when a plurality of types of monocarboxylic acids (B1, B2, B3,..., Bn) are present, the number average molecular weight M ₂ ′ of the monocarboxylic acid is set in place of the molecular weight M ₂ of the monocarboxylic acid. Use. M ₂ ′ represents the molecular weight of a plurality of types of monocarboxylic acids (B1, B2, B3,..., Bn), M _B1 , M _B2 , M _{B3 ,.} When the monocarboxylic acid content is N _B1 , N _B2 , N _B3 ,..., N _Bn (mol / mol), it is represented by the following formula.
M ₂ '= ΣM _Bn N _Bn

Further, when a plurality of types of diamines (C1, C2, C3,..., Cn) are present, the number average molecular weight M ₃ ′ of the diamine is used instead of the molecular weight M ₃ of the diamine. M ₃ ′ is the molecular weight of each of a plurality of diamines (C1, C2, C3,..., Cn), M _C1 , M _C2 , M _{C3 ,. Is} represented by the following equation, where N _C1 , N _C2 , N _C3 ,..., N _Cn (mol / mol).
M ₃ '= ΣM _Cn N _Cn

Of the above formulas (A) and (B), when the diamine involved in the polymerization reaction is equal to or less than the equivalent of the dicarboxylic acid involved in the polymerization reaction, the formula (A) is applied, and the diamine involved in the polymerization reaction However, when it exceeds the equivalent of the dicarboxylic acid participating in a polymerization reaction, Formula (B) is applied. That is, equation (A) is effective when α ≦ 1, and equation (B) is effective when α> 1.
In addition, when α obtained based on the formula (A) exceeds 1, or when α obtained based on the formula (B) is 1 or less, there are too many impurities and complete control cannot be performed. The molecular weight equivalent to the target molecular weight cannot be obtained. However, even in such a case, it is possible to bring the molecular weight close to the target molecular weight as much as possible by performing the polycondensation reaction after controlling the charged amounts of dicarboxylic acid and diamine so that α = 1.

A calculation example of the above formulas (A) and (B) is shown in FIG. FIG. 1 shows the content of monocarboxylic acid contained in sebacic acid β mol% calculated based on the formula (A) or (B) when the reaction rate of amino group or carboxyl group is 1.000. FIG. 3 is a graph showing the relationship between the charge molar ratio α of diamine and dicarboxylic acid for obtaining a polyamide resin having a number average molecular weight Mn of 10,000, 20000 or 50000. In each of the graphs, in formulas (A) and (B), the molecular weight M _{1 of} sebacic acid involved in the polymerization reaction is 202.2475, the molecular weight M _{2 of} heptanoic acid contained in sebacic acid is 130.1849, and is involved in the polymerization reaction. The molecular weight M ₃ of metaxylylenediamine to be calculated is 136.1943, the molecular weight M _{4 of} water is 18.01528, the reaction rate P _{A of} amino group is 1.000, and the reaction rate of carboxyl group is P _C = 1.000. ing.

  In FIG. 1, the straight line of the data series indicated by black circles is a relational expression between α and β calculated by the equation (A) when the number average molecular weight Mn is 10,000, The straight line of the data series shown is a relational expression between α and β calculated by the formula (B) when the number average molecular weight Mn is 10,000. The straight line of the data series indicated by the black square marks is the relational expression between α and β calculated by the formula (A) when the number average molecular weight Mn is 20000, and the data indicated by the white square marks The straight line of the series is a relational expression between α and β calculated by the equation (B) when the number average molecular weight Mn is 20000. The straight line of the data series indicated by the black triangle mark is the relational expression between α and β calculated by the formula (A) when the number average molecular weight Mn is 50000, and the data indicated by the open triangle mark The straight line of the series is a relational expression between α and β calculated by the equation (B) when the number average molecular weight Mn is 50000.

Specifically, for example, when a polyamide resin having a number average molecular weight Mn of 20000 is desired, when the content β of monocarboxylic acid contained in sebacic acid is 2 mol%, the graph of the formula (A) in FIG. Is determined as α being approximately 0.995, and α is determined as approximately 1.005 from the graph of the formula (B). Based on the above formula (1), the charged amounts of dicarboxylic acid and diamine are adjusted so that the obtained α (= about 0.995 or about 1.005) is obtained, and the amino group reaction rate P _A = 1.000. Alternatively, by performing the polycondensation reaction with the carboxyl group reaction rate P _C = 1.000, a desired polyamide resin having a number average molecular weight Mn of 20000 can be efficiently produced.

(Phosphorus atom-containing compounds, alkali metal compounds)
In the polycondensation of the polyamide resin, it is preferable to add a phosphorus atom-containing compound in the polycondensation system of the polyamide from the viewpoint of promoting the amidation reaction. By adding a phosphorus atom-containing compound, it acts as a catalyst for the polycondensation reaction, and it is possible to prevent the polyamide from being colored by oxygen present in the polycondensation system.
Phosphorus atom-containing compounds include hypophosphorous acid alkali metal salt, hypophosphorous acid alkaline earth metal salt, phosphorous acid alkali metal salt, phosphorous acid alkaline earth metal salt, phosphoric acid alkali metal At least one selected from the group consisting of a salt, an alkaline earth metal salt of phosphoric acid, an alkali metal salt of pyrophosphoric acid, an alkaline earth metal salt of pyrophosphoric acid, an alkali metal salt of metaphosphoric acid, and an alkaline earth metal salt of metaphosphoric acid It is preferable to use seeds. In addition, the phosphorus atom containing compound which can be used by this invention is not limited to these compounds.

  Specific examples of the phosphorus atom-containing compound include sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, calcium hypophosphite, magnesium hypophosphite, sodium phosphite, sodium hydrogen phosphite, sodium hypophosphite, Potassium phosphate, potassium hydrogen phosphite, lithium phosphite, lithium hydrogen phosphite, magnesium phosphite, magnesium hydrogen phosphite, calcium phosphite, calcium hydrogen phosphite, sodium phosphate, disodium hydrogen phosphate , Sodium dihydrogen phosphate, potassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, magnesium phosphate, dimagnesium hydrogen phosphate, magnesium dihydrogen phosphate, calcium phosphate, dicalcium hydrogen phosphate, dibasic phosphate Calcium hydrogen, lithium phosphate, dilithium hydrogen phosphate, phosphorus Dihydrogen lithium, sodium pyrophosphate, potassium pyrophosphate, magnesium pyrophosphate, calcium pyrophosphate, lithium pyrophosphate, sodium metaphosphate, potassium metaphosphate, magnesium metaphosphate, calcium metaphosphate, lithium metaphosphate, or a mixture thereof can be exemplified. Among these, sodium hypophosphite, potassium hypophosphite, calcium hypophosphite, magnesium hypophosphite, calcium phosphite, calcium hydrogen phosphite, calcium dihydrogen phosphate are preferable, sodium hypophosphite, More preferred is calcium phosphite. These phosphorus atom-containing compounds may be hydrates.

  It is preferable that the addition amount of a phosphorus atom containing compound is 0.1-1000 ppm in conversion of the phosphorus atom concentration in a polyamide compound, More preferably, it is 1-600 ppm, More preferably, it is 5-400 ppm. If it is 0.1 ppm or more, the polyamide compound is difficult to be colored during polymerization, and transparency is increased. If it is 1000 ppm or less, the polyamide compound is less likely to be gelled, and it is possible to reduce the mixing of fish eyes considered to be caused by the phosphorus atom-containing compound into the molded product, thereby improving the appearance of the molded product.

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

(Polycondensation method)
Examples of the polycondensation method of the polyamide resin include, but are not limited to, a pressurized salt method, a normal pressure dropping method, a pressure dropping method, and a reactive extrusion method.

<Pressurized salt method>
The pressurized salt method is a method of performing melt polycondensation under pressure using a nylon salt as a raw material. Specifically, after preparing a nylon salt aqueous solution composed of diamine and dicarboxylic acid, the aqueous solution is concentrated and then heated under pressure to polycondensate while removing condensed water. While the inside of the can is gradually returned to normal pressure, the temperature is raised to about the melting point of the polyamide resin + 10 ° C. and held, and then the pressure is gradually reduced to 0.02 MPaG and kept at the same temperature to continue polycondensation. To do. When a certain stirring torque is reached, the inside of the can is pressurized to about 0.3 MPaG with nitrogen to recover the polyamide resin.

<Normal pressure dropping method>
In the normal pressure dropping method, diamine is continuously added dropwise to the heated and melted dicarboxylic acid under normal pressure, and polycondensation is performed while removing condensed water. The polycondensation reaction is performed while raising the temperature of the reaction system so that the reaction temperature does not fall below the melting point of the polyamide resin to be produced.
Compared with the pressurized salt method, the atmospheric pressure dropping method does not use water to dissolve the salt, so the yield per batch is large, and the reaction rate is not required for vaporization / condensation of raw material components. The process time can be shortened.

<Pressure dropping method>
In the pressure dropping method, first, dicarboxylic acid is charged into a polycondensation can and melt mixed. Next, diamine is continuously added dropwise to the dicarboxylic acid heated and melted while pressurizing the inside of the can preferably to about 0.3 to 0.4 MPaG, and polycondensation is performed while removing condensed water. At this time, the polycondensation reaction is performed while raising the temperature of the reaction system so that the reaction temperature does not fall below the melting point of the produced polyamide resin. When the set molar ratio is reached, the diamine is dropped and the temperature inside the can is gradually returned to normal pressure, while the temperature is raised to about the melting point of the polyamide resin + 10 ° C. and held, and then gradually reduced to 0.02 MPaG. While maintaining the temperature as it is, the polycondensation is continued. When a certain stirring torque is reached, the inside of the can is pressurized to about 0.3 MPaG with nitrogen to recover the polyamide resin.
The pressure dropping method is useful when a volatile component is used as a monomer. In addition, the pressure drop method does not use water to dissolve the salt compared to the pressure salt method, so the yield per batch is large and the reaction time can be shortened as in the atmospheric pressure drop method. A polyamide resin with low yellowness can be obtained.

<Reactive extrusion method>
In the reactive extrusion method, a polyamide oligomer composed of diamine and dicarboxylic acid is melted and kneaded with an extruder and reacted. In order to sufficiently react, it is preferable to use a screw suitable for reactive extrusion and to use a twin screw extruder having a large L / D.

From the viewpoint of production cost, the atmospheric pressure dropping method or the pressure dropping method is preferable. That is, a method in which diamine is continuously added to a dicarboxylic acid in a molten state and polycondensed under normal pressure or pressure is preferable.
As preferable reaction conditions when the atmospheric pressure dropping method or the pressure dropping method is applied, the molten dicarboxylic acid is heated to 150 to 200 ° C. at 0.1 to 0.5 MPaA, and then the diamine is 1. The temperature is gradually raised to 220 to 300 ° C. while dropping over 5 to 3 hours. Since the melting point rises as the dropping of diamine proceeds, the temperature at this time always maintains a temperature higher than the melting point by 5 ° C. or more. After completion of dropping, the pressure is gradually reduced to 0.08 MPaA over 0.5 to 2 hours, and the reduced pressure state is maintained for 0 to 2 hours.
Moreover, when applying a normal pressure dropping method or a pressure dropping method, it is preferable that the molten dicarboxylic acid is filtered before being introduced into the reaction vessel. By removing the insoluble matter by filtering the dicarboxylic acid in the molten state, fish eyes in the obtained polyamide resin can be reduced. It does not specifically limit as a means to filter, Filters, such as a membrane filter, a sintered metal filter, and a glass fiber filter, can be used.

<Process for increasing the degree of polymerization>
The polyamide resin produced by the polycondensation method can be used as it is, but may be subjected to a step for further increasing the degree of polymerization. Further examples of the step of increasing the degree of polymerization include reactive extrusion in an extruder and solid phase polymerization. As a heating device used in solid phase polymerization, a continuous heating drying device, a tumble dryer, a conical dryer, a rotary drum heating device called a rotary dryer, etc., and a rotary blade inside a nauta mixer are provided. A conical heating device can be preferably used, but a known method and device can be used without being limited thereto. In particular, when solid-phase polymerization of polyamide resin is performed, the heating device of the rotating drum type among the above-mentioned devices can seal the inside of the system and facilitate polycondensation in a state where oxygen that causes coloring is removed. Are preferably used.

(Polyamide resin)
The polyamide resin obtained by the method of the present invention is a polyamide resin containing a diamine unit and a dicarboxylic acid unit, and 50 mol% or more of the dicarboxylic acid unit is derived from sebacic acid.
The dicarboxylic acid unit of the polyamide resin obtained by the method of the present invention is 50 mol% or more, preferably 70 mol% or more, more preferably 90 mol% or more, still more preferably 100 mol% of dicarboxylic acid units. Contains substantially 100 mol%. It is preferred that all dicarboxylic acid units are derived from sebacic acid. Examples of the compound that can constitute a dicarboxylic acid unit other than the sebacic acid unit include dicarboxylic acids other than sebacic acid, and are the same as those described as the dicarboxylic acid.

Examples of the compound capable of constituting the diamine unit of the polyamide resin obtained by the method of the present invention include those described as the diamine, and are appropriately selected according to the properties of the target polyamide.
For example, from the viewpoint of mechanical properties (strength, elastic modulus) and gas barrier properties of polyamide, the diamine unit of the polyamide resin obtained by the method of the present invention is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably. Is derived from xylylenediamine and / or bis (aminomethyl) cyclohexane in an amount of 90 mol% or more, more preferably substantially 100 mol%.

  Preferable specific examples of the polyamide resin obtained by the method of the present invention include polytetramethylene sebacamide (nylon 410), polyhexamethylene sebacamide (nylon 610), polydecamethylene sebacamide (nylon 1010), polymer Examples include taxylylene sebacamide (nylon MXD10), polyparaxylylene sebacamide (nylon PXD10), polymetaxylylene sebacamide / polyparaxylylene sebacamide copolymer (nylon MP10), and the like.

(Polyamide resin composition)
The polyamide resin obtained by the method of the present invention is blended with various additives generally used for polymer materials within the range that does not impair the effects of the present invention, depending on the performance required for the polyamide resin of the present invention. Thus, a polyamide resin composition can be obtained. Specific examples of additives include antioxidants, colorants, light stabilizers, matting agents, heat stabilizers, weathering stabilizers, UV absorbers, crystallization nucleating agents, plasticizers, nanofillers, and other fillers. Examples thereof include flame retardants, lubricants, antistatic agents, anti-coloring agents, anti-gelling agents, and release agents, but are not limited thereto, and various materials may be mixed.

A method of blending an additive or a resin with the polyamide resin is not particularly limited, and can be performed by a desired method. For example, the additive may be added during the polycondensation reaction of the polyamide resin, or a predetermined amount of the additive and the resin may be blended in the polyamide resin and melt-kneaded or dry blended.
The melt kneading can be performed by a conventionally known method. For example, a method of melt kneading under heating using a single-screw or twin-screw extruder, a kneader, a mixing roll, a Banbury mixer, a vent-type extruder, or a similar device can be exemplified. All the materials may be charged all at once from the root of the extruder and melt-kneaded, or the pellets may be manufactured by first kneading with the side-feeding fibrous filler while melting the resin component and melting. Good. Alternatively, pellet blending may be performed after different types of compound materials are pelletized, or a method in which some powder components and liquid components are separately blended may be used.

(Molding)
The polyamide resin obtained by the method of the present invention and the resin composition containing the same are molded into a desired shape by a known molding method such as injection molding, blow molding, extrusion molding, compression molding, stretching, vacuum molding, or the like. Can be manufactured. The engineering plastic can be molded not only in a molded body but also in the form of a film, a sheet, a hollow container, a fiber, a tube and the like, and can be suitably used for industrial materials, industrial materials, household goods and the like.

As a molded article comprising the polyamide resin obtained by the method of the present invention and a resin composition containing the polyamide resin, it can be suitably used for various applications such as electric and electronic parts, sliding parts, blow-molded articles, and automobile parts. Can do.
Specific examples of the electrical / electronic components include electrical connectors such as connectors, switches, IC / LED housings, sockets, relays, resistors, capacitors, capacitors, and coil bobbins.
Specific examples of the sliding parts include various sliding materials such as bearings, gears, bushes, spacers, rollers, and cams.
Specific examples of automotive parts include engine mounts, engine covers, torque control levers, window regulators, headlight reflectors, door mirror stays, and the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. In the examples, various measurements were performed by the following methods.

(1) Content of monocarboxylic acid in dicarboxylic acid A hydrochloric acid-methanol solution was prepared by diluting 1.0 ml of concentrated hydrochloric acid to 100 ml with methanol. 100 mg of sebacic acid was dissolved in 10 ml of hydrochloric acid methanol solution, and heated in a sealed vial at 100 ° C. for 1 hour. The solution after cooling was subjected to gas chromatography. Based on the area ratio of peaks derived from dicarboxylic acid or monocarboxylic acid in the gas chromatogram, the content of monocarboxylic acid in the dicarboxylic acid was quantified.

(2) Reaction rate of amino group and carboxyl group The reaction rate of amino group and carboxyl group of the polyamide resin was determined from the following formula.
P _A = [NH ₂ ] × W / (2 ×)
P _C = [COOH] × W / (2Y− (β / 100) Y)
(In the formula, X, Y and beta, have the same meanings as X, Y and beta in the formula (1), P _A and W have the same meanings as P _A and W in the formula (2), P _C is the formula ( 7) the same meanings as P _C in. also, represents a [NH _2] is the terminal amino group concentration (mol / g of polyamide resin), [COOH] is the terminal carboxyl group concentration in the polyamide resin (mol / g) .)
The terminal amino group concentration was measured by dissolving 0.3 g of polyamide resin in 30 ml of a phenol / ethanol (4: 1) mixed solution with stirring at 20 to 30 ° C. and titrating with 0.01 N hydrochloric acid.
The terminal carboxyl group concentration was measured by dissolving 0.2 g of polyamide resin in 30 ml of benzyl alcohol at 190 ° C. with stirring, cooling to 100 ° C., adding 5 ml of methanol, and titrating with 0.01 N sodium hydroxide aqueous solution. .

(3) Number average molecular weight Mn of polyamide resin
The number average molecular weight Mn of the polyamide resin was measured by gel permeation chromatography (GPC) “Shodex (registered trademark) GPC SYSTEM-11” (trade name) manufactured by Showa Denko K.K. Hexafluoroisopropanol (HFIP) was used as the solvent, and 10 mg of the sample polyamide was dissolved in 10 g of HFIP and used for the measurement. The measurement conditions were two “HFIP-806M” (trade name) of a GPC standard column (column size 300 × 8.0 mm ID) manufactured by the same company as a measurement column, and a reference column “HFIP-800” (trade name). Were used, the column temperature was 40 ° C., and the solvent flow rate was 1.0 mL / min. Using polymethyl methacrylate as a standard sample and “SIC-480II” (trade name) manufactured by the same company as data processing software, the number average molecular weight Mn of the polyamide resin was determined.

Reference example 1
As a result of analyzing the sebacic acid used by gas chromatography, no monocarboxylic acid was detected (β = 0.0 mol%). This sebacic acid (15.000 kg) was heated and melted at 170 ° C. at 0.4 MPaA in a reaction vessel, and then the mixture was mixed with a molar ratio of metaxylylenediamine and paraxylylenediamine of 7: 3 while stirring the contents. 9.980 kg of diamine (MPXDA) was gradually added dropwise over 2 hours, and the temperature was raised to 250 ° C. (α = 0.9880). After the temperature rise, the pressure was gradually decreased to 0.08 MPaA over 1 hour and held for 0.5 hour. After completion of the reaction, the contents were taken out in a strand shape and pelletized with a pelletizer. The resulting pellet, amino group reaction rate P _A = 0.995, was polyamide resin having a number average molecular weight of 13800. The obtained pellets were charged into a tumbler and subjected to solid phase polymerization under reduced pressure. As a result, a polyamide resin with P _A = 0.998 and a number average molecular weight of 18900 was obtained.

Example 1
As a result of analyzing the sebacic acid used by gas chromatography, 2.0 mol% of heptanoic acid was contained as an impurity (β = 2.0 mol%). In using this sebacic acid, α was calculated based on the formula (A) to obtain a polyamide resin having a number average molecular weight of 13800 at an amino group reaction rate P _A = 0.995. Α = 0.9981 there were. Moreover, α was obtained when α was obtained when a polyamide resin having a number average molecular weight of 13800 was obtained based on the formula (B) when the carboxyl group reaction rate P _C = 0.995. Α = 1.0019. . Therefore, α = 0.9981 was adjusted by changing the amount of the mixed diamine MPXDA used to 10.53 kg, and other conditions were produced in the same manner as in Reference Example 1. As a result, a polyamide resin having an amino group reaction rate P _A = 0.995 and a number average molecular weight of 13700 was obtained as a pellet taken out from the reaction can. Further, to obtain a P _A = 0.998, the number average polyamide resin having a molecular weight of 18800 as a solid phase polymerization product.
Thus, by adjusting α according to β, a molecular weight equivalent to that of Reference Example 1 using sebacic acid having high purity could be obtained, and sufficient molecular weight control was possible.

Comparative Example 1
As a result of analyzing the sebacic acid used by gas chromatography, 2.0 mol% of heptanoic acid was contained as an impurity (β = 2.0 mol%). It was produced in the same manner as in Reference Example 1 except that this sebacic acid was used. That is, the usage-amounts of diamine and dicarboxylic acid were not changed, and were the same as each usage-amount in Reference Example 1. As a result, a polyamide resin having an amino group reaction rate P _A = 0.995 and a number average molecular weight of 10400 was obtained as a pellet taken out from the reaction can. Further, as the solid phase polymerization product to obtain P _A = 0.998, the number average polyamide resin having a molecular weight 13000. In addition, it was 0.9909 when (alpha) at this time was computed according to the said Formula (1).
Thus, when α was not adjusted according to β, a molecular weight equivalent to that of Reference Example 1 using high-purity sebacic acid could not be obtained, and sufficient molecular weight control could not be performed.

Comparative Example 2
As a result of analyzing the sebacic acid used by gas chromatography, 3.0 mol% of heptanoic acid was contained as an impurity (β = 3.0 mol%). It was produced in the same manner as in Reference Example 1 except that this sebacic acid was used. That is, the usage-amounts of diamine and dicarboxylic acid were not changed, and were the same as each usage-amount in Reference Example 1. As a result, a polyamide resin having an amino group reaction rate P _A = 0.995 and a number average molecular weight 9200 was obtained as a pellet taken out from the reaction can. Further, as a solid phase polymerization product, a polyamide resin having P _A = 0.998 and a number average molecule 11200 was obtained. In addition, it was 0.9923 when (alpha) at this time was computed according to the said Formula (1).
Thus, when α was not adjusted according to β, a molecular weight equivalent to that of Reference Example 1 using high-purity sebacic acid could not be obtained, and sufficient molecular weight control could not be performed.

Example 2
As a result of analyzing the sebacic acid used by gas chromatography, 3.0 mol% of heptanoic acid was contained as an impurity (β = 3.0 mol%). In the use of sebacic acid, α was calculated based on the formula (A) to obtain a polyamide resin having a number average molecular weight of 13800 at an amino group reaction rate P _A = 0.995. Α = 1.0032 Yes, the upper limit 1 of α for which the formula (A) is effective was exceeded. Further, when α was obtained when a polyamide resin having a number average molecular weight of 13800 was calculated based on the formula (B) when the carboxyl group reaction rate P _C = 0.995, α = 0.9967, The lower limit value 1 of α for which the formula (B) is effective was lower. Therefore, α = 1.0000 was adjusted by changing the amount of mixed diamine MPXDA used to 10.57 kg, and other conditions were produced in the same manner as in Reference Example 1. As a result, a polyamide resin having an amino group reaction rate P _A = 0.995 and a number average molecular weight of 12,000 was obtained as a pellet taken out from the reaction can. Further, as the solid phase polymerization product to obtain P _A = 0.998, polyamide resin having a number average molecular weight of 15800.
Since β was large, even when α was adjusted to the maximum, a molecular weight equivalent to that of Reference Example 1 using high-purity sebacic acid could not be obtained, but from Comparative Example 2 in which α was not adjusted. Was able to obtain a polyamide resin having a molecular weight close to that of Reference Example 1, and the molecular weight could be controlled by adjusting α.

According to the method of the present invention, a polyamide resin having a number average molecular weight of about 10,000 to 50,000 can be efficiently produced using sebacic acid as a dicarboxylic acid. Since the polymerization can be performed in consideration of the influence of the purity of sebacic acid, it is possible to efficiently produce a polyamide resin controlled to have a desired molecular weight even if inexpensive sebacic acid with low purity is used.
Since the polyamide resin obtained by the method of the present invention has a characteristic of low water absorption and excellent dimensional stability, it can be suitably used for industrial, industrial and household products such as automobile parts, electrical and electronic equipment parts, and machine parts. it can.

Claims (10)

Dicarboxylic acid containing diamine unit and sebacic acid unit at least 50 mol% by conducting polymerization reaction using diamine and dicarboxylic acid containing sebacic acid containing more than 0 mol% and less than 6 mol% monocarboxylic acid Comprising a unit and a polyamide resin having a desired number average molecular weight,
Based on the following formula (A) or (B), the desired amino acid or carboxyl group reaction rate P _A or P _C when using sebacic acid containing β mol% monocarboxylic acid is used. Obtaining the charged molar ratio α of diamine and dicarboxylic acid to obtain a polyamide resin having a number average molecular weight Mn,
A process for producing a polyamide resin, wherein a polycondensation reaction is carried out by controlling the amounts of dicarboxylic acid and diamine charged so as to satisfy the required α.
Mn = 2 [(α (2 -β / 100) (M 3/2-M 4 P A) - (M 1 -M 2) (β / 100) + M 1)] / (2-α (2-β / 100) (2P _A -1)) (A)
Mn = 2 [(α (2 -β / 100) (M 3/2) - (M 1 -M 2 -M 4 P C) (β / 100) + M 1 -2M 4 P C)] / ((α -2P _C ) (2-β / 100) +2) (B)
(If the diamine involved in the polymerization reaction is less than or equal to the equivalent of the dicarboxylic acid involved in the polymerization reaction, the formula (A) is applied, and the diamine involved in the polymerization reaction is equivalent to the dicarboxylic acid involved in the polymerization reaction. In the case of exceeding, the formula (B) is applied.
In the formulas (A) and (B), β represents the content of the monocarboxylic acid contained in the dicarboxylic acid, and is more than 0 mol% and less than 6 mol%. M ₁ represents the molecular weight of the dicarboxylic acid involved in the polymerization reaction, M ₂ represents the molecular weight of the monocarboxylic acid contained in the dicarboxylic acid, M ₃ represents the molecular weight of the diamine involved in the polymerization reaction, M ₄ represents the molecular weight of water, P _a represents the reaction rate of the amino group, P _C represents the reaction rate of the carboxyl group. )
α = 2X / (2Y− (β / 100) Y) (1)
(In the formula, X represents the number of moles (mol) of the charged diamine, Y represents the number of moles (mol) of the charged dicarboxylic acid, and β represents the content of the monocarboxylic acid contained in the dicarboxylic acid. , More than 0 mol% and less than 6 mol%.)   The method for producing a polyamide resin according to claim 1, wherein the number average molecular weight Mn is 10,000 to 50,000. The reaction rate P _A or P _C is determined from the polyamide obtained using the sebacic acid which does not contain monocarboxylic acid, method for producing the polyamide resin according to claim 1 or 2.   The method for producing a polyamide resin according to any one of claims 1 to 3, wherein diamine is continuously added to the dicarboxylic acid in a molten state and polycondensed under normal pressure or under pressure.   The method for producing a polyamide resin according to claim 4, wherein the molten dicarboxylic acid is filtered before being introduced into the reaction vessel.   The method for producing a polyamide resin according to any one of claims 1 to 5, wherein 70 mol% or more of the diamine unit is derived from xylylenediamine and / or bis (aminomethyl) cyclohexane.   The method for producing a polyamide resin according to claim 6, wherein the xylylenediamine is metaxylylenediamine, paraxylylenediamine, or a mixture thereof.   The method for producing a polyamide resin according to claim 6, wherein the bis (aminomethyl) cyclohexane is 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane or a mixture thereof.   The method for producing a polyamide resin according to claim 1, wherein all of the dicarboxylic acid units are derived from sebacic acid. When performing a polymerization reaction using a diamine and a dicarboxylic acid containing sebacic acid containing more than 0 mol% and less than 6 mol% of a monocarboxylic acid, a dicarboxylic acid containing 50 mol% or more of a diamine unit and a sebacic acid unit A method for controlling the number average molecular weight Mn of a polyamide resin containing units,
Based on the following equation (A) or (B), when the monocarboxylic acid with sebacic acid containing β mol%, the reaction rate P _A or P _C of a predetermined amino or carboxyl group, the objective Obtaining the charged molar ratio α of diamine and dicarboxylic acid to obtain a polyamide resin having a number average molecular weight Mn,
A method for controlling the molecular weight of a polyamide resin, in which a polycondensation reaction is performed by adjusting the charged amounts of dicarboxylic acid and diamine based on the following formula (1) so as to obtain the required α.
Mn = 2 [(α (2 -β / 100) (M 3/2-M 4 P A) - (M 1 -M 2) (β / 100) + M 1)] / (2-α (2-β / 100) (2P _A -1)) (A)
Mn = 2 [(α (2 -β / 100) (M 3/2) - (M 1 -M 2 -M 4 P C) (β / 100) + M 1 -2M 4 P C)] / ((α -2P _C ) (2-β / 100) +2) (B)
(If the diamine involved in the polymerization reaction is less than or equal to the equivalent of the dicarboxylic acid involved in the polymerization reaction, the formula (A) is applied, and the diamine involved in the polymerization reaction is equivalent to the dicarboxylic acid involved in the polymerization reaction. In the case of exceeding, the formula (B) is applied.
In the formulas (A) and (B), β represents the content of the monocarboxylic acid contained in the dicarboxylic acid, and is more than 0 mol% and less than 6 mol%. M ₁ represents the molecular weight of the dicarboxylic acid involved in the polymerization reaction, M ₂ represents the molecular weight of the monocarboxylic acid contained in the dicarboxylic acid, M ₃ represents the molecular weight of the diamine involved in the polymerization reaction, M ₄ represents the molecular weight of water, P _a represents the reaction rate of the amino group, P _C represents the reaction rate of the carboxyl group. )
α = 2X / (2Y− (β / 100) Y) (1)
(In the formula, X represents the number of moles (mol) of the charged diamine, Y represents the number of moles (mol) of the charged dicarboxylic acid, and β represents the content of the monocarboxylic acid contained in the dicarboxylic acid. , More than 0 mol% and less than 6 mol%.)

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