JP2000186142A - Production of polyamide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a semi-aromatic polyamide having excellent color tone and hydrolysis resistance. SOLUTION: This method for producing a polyamide comprising dicarboxylic acid units containing terephthalic acid units in an amount of 60-100 mol.% and diamine units containing 6-18C aliphatic alkylenediamine units in an amount of 60-100 mol.% comprises producing a prepolymer having a reaction rate of 75-97% between the amino groups of the raw material amine and the carboxy groups of the raw material carboxylic acid, a terminal carboxy group [COOH] (mmol/g)/terminal amino group [NH2] (mmol/g) of 150/100 to 50/100 g, and an absolute [COOH]-[NH2] value of <=0.2 mmol/g, and then melt-polymerizing the produced prepolymer under conditions comprising a temperature of <=350 deg.C and a melt retention time of <=5 min., thus producing the polyamide having a reaction rate of >=98% between the amino groups of the raw material amine and the carboxy groups of the raw material carboxylic acid, a terminal carboxy group [COOH] of <=0.2 mmol/g and a terminal amino group [NH2] of <=0.2 mmol/g.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a semi-aromatic polyamide. More specifically, the present invention relates to a method for producing a semi-aromatic polyamide having remarkably excellent color tone and hydrolysis resistance.

[0002]

2. Description of the Related Art Conventionally, crystalline polyamides represented by nylon 6, nylon 66, etc. have been widely used as fibers for clothing, industrial materials, or general-purpose engineering plastics because of their excellent properties and ease of melt molding. However, on the other hand, problems such as insufficient heat resistance and poor dimensional stability due to water absorption have been pointed out. In particular, in the electric and electronic fields that require reflow soldering heat resistance accompanying the development of surface mount technology (SMT) in recent years, or in the engine room parts of automobiles where the demand for heat resistance is increasing year by year, the use of the conventional polyamide is difficult. It ’s getting harder,
There is a demand for polyamides having better heat resistance.

[0003] In response to such a demand in the world, various semi-aromatic polyamides comprising terephthalic acid and aliphatic alkylenediamine have been proposed. The most typical one is
A semi-aromatic polyamide composed of 1,6-hexanediamine and terephthalic acid (sometimes abbreviated as PA6-T) is used as a main skeleton, and a third component such as isophthalic acid or adipic acid is copolymerized and melted. Modified PA6 with moldability
T. As a method for producing modified PA6-T, a melt polymerization method using a twin-screw extruder is known. JP 61
JP-A-228022 proposes a method of heating a low-order condensate in a molten state under shearing conditions using a kneading means such as a twin-screw extruder to form a prepolymer, and then subjecting the prepolymer to solid phase polymerization. I have. Japanese Patent Application Laid-Open No. 4-53825 proposes a method of increasing the degree of polymerization while adding an insufficient carboxylic acid component when polymerizing an amino group-rich prepolymer by a melt extruder. Japanese Patent Application Laid-Open No. H8-109225 discloses that a screw segment having an L / D of 2 or less is used.
A method of increasing the degree of polymerization using an axial screw extruder has been proposed.

[0004]

According to the study of the present inventors, the semi-aromatic polyamide obtained by the above-mentioned method is not always satisfactory in physical properties such as color tone and hydrolysis resistance. .

It is an object of the present invention to provide not only excellent color tone,
An object of the present invention is to provide a method for producing a semi-aromatic polyamide having excellent hydrolysis resistance.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, when producing a semi-aromatic polyamide, specified a prepolymer having a specific conversion and a terminal structure. It has been found that a semi-aromatic polyamide having excellent hydrolysis resistance and excellent color tone can be obtained only by melt polymerization under the conditions described above, and the present invention has been completed.

That is, the present invention is as follows. When producing a polyamide comprising a dicarboxylic acid unit containing 60 to 100 mol% of terephthalic acid units and a diamine unit containing 60 to 100 mol% of aliphatic alkylenediamine units having 6 to 18 carbon atoms, (1) raw materials The reaction rate between the amino group of the amine and the carboxyl group of the starting carboxylic acid is 75% to 97%, and the terminal carboxyl group [COO
H] (mmol / g) / Terminal amino group [NH ₂ ] (mmol / g) is 150
/ 100 to 50/100, and [COOH] - [NH _2] of the absolute value to produce a prepolymer is less than 0.2 mmol / g, then (2) The prepolymer of 350 ° C. or less Melt polymerization at a temperature and a melt residence time of 5 minutes or less,
The reaction rate between the amino group of the starting amine and the carboxyl group of the starting carboxylic acid is 98% or more, and the terminal carboxyl group [COOH]
Is less than 0.2 mmol / g and the terminal amino group [NH ₂ ] is 0.2
A method for producing a polyamide, characterized in that a polyamide of not more than mmol / g is obtained. An aliphatic alkylenediamine unit having 6 to 18 carbon atoms,
The above-mentioned production method, which is an aliphatic alkylenediamine unit having 6 to 9 carbon atoms. An aliphatic alkylenediamine unit having 6 to 18 carbon atoms,
1,9-nonanediamine unit and 2-methyl-1,8
-The method according to the above, which is at least one selected from the group consisting of octanediamine units. The method according to any one of the above-mentioned items, wherein the prepolymer is melt-polymerized at a temperature of 340 ° C. or lower by a twin-screw extruder.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. The semi-aromatic polyamide produced according to the present invention contains 60 to 100 terephthalic acid units as dicarboxylic acid units.
Mol%, preferably 70 to 100 mol%, more preferably 90 to 100 mol%. 6 terephthalic acid units
If the amount is less than 0 mol%, various physical properties such as low water absorption and chemical resistance of the polyamide deteriorate.

The dicarboxylic acid unit other than the terephthalic acid unit includes, for example, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dimethylmalonic acid, 3,3- Aliphatic dicarboxylic acids such as diethylsuccinic acid, 2,2-dimethylglutaric acid, 2-methyladipic acid and trimethyladipic acid; alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid Acid; isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7
-Naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-
Phenylenedioxydiacetic acid, diphenic acid, 4,4′-biphenyldicarboxylic acid, 4,4′-oxydibenzoic acid,
Examples include units derived from aromatic dicarboxylic acids such as diphenylmethane-4,4'-dicarboxylic acid and diphenylsulfone-4,4'-dicarboxylic acid. One or more of these units can be used. Among these, a unit derived from an aromatic dicarboxylic acid is preferred. Further, a unit derived from a polyvalent carboxylic acid such as trimellitic acid, trimesic acid, pyromellitic acid or the like can be contained within a range in which the polyamide can be melt-molded.

The semi-aromatic polyamide produced according to the present invention contains 60 to 100 mol%, preferably 75 to 100 mol%, more preferably 90 to 100 mol% of an aliphatic alkylenediamine unit having 6 to 18 carbon atoms as a diamine unit. Mol%. When the content of the aliphatic alkylenediamine unit having 6 to 18 carbon atoms is less than 60 mol%, various physical properties such as heat resistance, low water absorption and chemical resistance of the polyamide are deteriorated. Examples of the aliphatic alkylenediamine unit having 6 to 18 carbon atoms include 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine , 1,11-
Linear aliphatic alkylenediamines such as undecanediamine and 1,12-dodecanediamine; 1-butyl-1,2
-Ethanediamine, 1,1-dimethyl-1,4-butanediamine, 1-ethyl-1,4-butanediamine, 1,
2-dimethyl-1,4-butanediamine, 1,3-dimethyl-1,4-butanediamine, 1,4-dimethyl-
1,4-butanediamine, 2,3-dimethyl-1,4-
Butanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2,5-
Dimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, 3,3-dimethyl-
1,6-hexanediamine, 2,2-dimethyl-1,6
-Hexanediamine, 2,2,4-trimethyl-1,6
-Hexanediamine, 2,4,4-trimethyl-1,6
-Hexanediamine, 2,4-diethyl-1,6-hexanediamine, 2,2-dimethyl-1,7-heptanediamine, 2,3-dimethyl-1,7-heptanediamine, 2,4-dimethyl-1 , 7-heptanediamine,
2,5-dimethyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine, 3-methyl-1,8
-Octanediamine, 4-methyl-1,8-octanediamine, 1,3-dimethyl-1,8-octanediamine, 1,4-dimethyl-1,8-octanediamine,
2,4-dimethyl-1,8-octanediamine, 3,4
-Dimethyl-1,8-octanediamine, 4,5-dimethyl-1,8-octanediamine, 2,2-dimethyl-
1,8-octanediamine, 3,3-dimethyl-1,8
And units derived from branched aliphatic alkylenediamines such as -octanediamine, 4,4-dimethyl-1,8-octanediamine, and 5-methyl-1,9-nonanediamine. One or more kinds can be used.

Among the above-mentioned aliphatic alkylenediamine units having 6 to 18 carbon atoms, aliphatic alkylenediamine units having 6 to 9 carbon atoms are preferable, and 1,6-hexanediamine and 2-methyl-1,8-octane are preferable. Diamine, 1,9-
Units derived from nonanediamine are more preferred,
1,9-nonanediamine (NMDA) units and 2-methyl-1,8-octanediamine (MODA) units are particularly preferred. Preferably, the NMDA unit and the MODA unit are NMDA unit: MODA unit of 100: 0 to 2
0:80 (molar ratio), preferably 99: 1 to 30:70, particularly preferably 98: 2 to 40:60. As the aliphatic alkylenediamine unit, 1,
By using a 9-nonanediamine unit and a 2-methyl-1,8-octanediamine unit together in the above ratio, a polyamide having particularly excellent heat aging resistance and color tone can be obtained.

Examples of the diamine units which can be used in addition to the above-mentioned aliphatic alkylenediamine units having 6 to 18 carbon atoms include aliphatic diamines such as ethylenediamine, propylenediamine and 1,4-butanediamine; cyclohexanediamine, methyl Cyclohexanediamine,
Alicyclic diamines such as isophorone diamine, norbornane dimethylamine and tricyclodecane dimethylamine; p
-Phenylenediamine, m-phenylenediamine, p-
Xylylenediamine, m-xylylenediamine, 4,
Examples include units derived from aromatic diamines such as 4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, and 4,4'-diaminodiphenylether, and one or more of these units are used. be able to.

In the present invention, first, as a first step, the reaction rate between the amino group of the starting amine and the carboxyl group of the starting carboxylic acid is 75% to 97%,
[COOH] (mmol / g) / Terminal amino group [NH ₂ ] (mmol / g) is 1
50/100 to 50/100, and [COOH]-[N
A prepolymer having an absolute value of H ₂ ] of 0.2 mmol / g or less is produced.

The above conversion is preferably 80% to 95%.
It is. When the reaction rate is within the above range, a polyamide having a small degree of coloring in a subsequent melt polymerization step and a high hydrolysis resistance can be obtained. This reaction rate can be easily controlled by employing appropriate reaction temperature and reaction time.

The method for producing the prepolymer is not particularly limited. For example, first, water is used as a solvent at 50 ° C.
A method in which a nylon salt is synthesized at a temperature of about 100 ° C. and then heated under pressure at a temperature of about 200 ° C. to 300 ° C. in a pressure vessel; a raw material amine and carboxylic acid are heated in a dispersion medium such as xylene; And a method of reacting an amine with a carboxylic acid chloride in a solvent such as DMF.

In the above prepolymer, the terminal carboxyl group [COOH] (mmol / g) / terminal amino group [N
H ₂ ] (mmol / g) needs to be 150/100 to 50/100, preferably 130/100 to 70/100.
100. When [COOH] / [NH ₂ ] is in this range, a polyamide having excellent hydrolysis resistance can be obtained.

Further, in the above prepolymer,
The absolute value of [COOH]-[NH ₂ ] needs to be 0.2 mmol / g or less. This [COOH]-[NH ₂ ] is preferably 0.1
It is 5 mmol / g or less. When the absolute value of [COOH]-[NH ₂ ] is in this range, a polyamide having excellent hydrolysis resistance can be obtained.

In order to control the terminal structure of the prepolymer within the above-mentioned range, the charged raw material is changed to a carboxyl group [C
The molar ratio of [OH] / amino group [NH ₂ ] is 112.5 / 100
~ 87.5 / 100, preferably 107.5 / 100 ~
Charged to a ratio of 92.5 / 100, 200 ° C
It is necessary to carry out the reaction under the conditions of 10 atmospheres or more.

The shape of the above-mentioned prepolymer is preferably any of powder, granule, and pellet.
As long as it does not hinder the melt polymerization equipment such as a screw extruder,
Some lump (eg, agglomerated particles) may be mixed. From the viewpoint of increasing the productivity in the subsequent melt polymerization step, the bulk specific gravity of the prepolymer is preferably 0.1 g / cc or more. Further, the prepolymer may contain a solvent such as water used in the production process, but from the viewpoint of increasing the productivity in the subsequent melt polymerization step, the solvent is reduced to about 5% or less by a method such as drying. It is preferable that it has been removed. Further, from the viewpoint of suppressing the coloring of the resin in the subsequent melt polymerization step, the prepolymer is preferably handled in a nitrogen atmosphere having an oxygen content of 100 ppm or less.

Next, as a second step, the prepolymer is melt-polymerized at a temperature of 350 ° C. or less and a melt residence time of 5 minutes or less to form a reaction between the amino group of the raw material amine and the carboxyl group of the raw material carboxylic acid. A polyamide having a reaction rate of 98% or more, a terminal carboxyl group [COOH] of 0.2 mmol / g or less, and a terminal amino group [NH ₂ ] of 0.2 mmol / g or less is obtained.

The melt polymerization apparatus used in the present invention is not particularly limited, but a twin-screw extruder is preferable because it has high production efficiency and can obtain a resin with little thermal deterioration. As the twin-screw extruder, a type having a vent port is preferable, and a type having two or more vent ports is more preferable. The vent port can be used under normal pressure as required, or under reduced pressure by suction with a pump. Normal,
It is preferable to set the first vent to be opened under the flow of nitrogen and to set the degree of decompression gradually higher after the second vent. With such a vent setting, the degree of polymerization can be efficiently increased. Also, from the viewpoint of giving a sufficient amount of heat for melting and polymerization,
Extruder L / D is 10 or more and 60 or less, and especially 15 or more and 5 or less.
It is preferably 0 or less, particularly preferably 20 or more and 40 or less.

In the present invention, the melt polymerization temperature is 350 ° C. or lower, preferably (melting point + 10 ° C.) to 340 ° C. If the melt polymerization temperature exceeds 350 ° C., only colored polyamides can be obtained. Since the resin temperature may be higher due to friction than the set temperature of the melt polymerization device,
The measurement is performed by installing a resin thermometer in the melt polymerization apparatus, or by measuring the resin temperature coming out of the nozzle with a thermometer.

In the present invention, the melt residence time in the melt polymerization apparatus is 5 minutes or less, preferably 1 minute to 4 minutes. Within this range, a polyamide having an excellent color tone can be obtained.

The polyamide obtained by melt-polymerizing the above prepolymer under the above conditions has a reaction rate of 98 between the amino group of the starting amine and the carboxyl group of the starting carboxylic acid.
%. This conversion is preferably 99 to 100%. Such a polyamide is obtained by employing the above melt polymerization conditions.

The obtained polyamide has a terminal carboxyl group [COOH] of 0.2 mmol / g or less and a terminal amino group
[NH ₂ ] needs to be 0.2 mmol / g or less. [C
When [OH] exceeds 0.2 mmol / g, the resulting polyamide has significantly poor hydrolysis resistance. [NH ₂ ] is 0.2 mm
When it exceeds ol / g, coloring becomes remarkable when the obtained polyamide is exposed to a high temperature for a long period of time. Preferably, the terminal carboxyl group [COOH] is 0.15 mmol / g or less, and the terminal amino group
[NH ₂ ] is 0.15 mmol / g or less. To control the terminal structure of the polyamide within the above range, as described above, the ratio of [COOH] / [NH ₂ ] is 150/100 to 50/1.
00 and the absolute value of [COOH]-[NH ₂ ] is 0.2 mm
It is necessary to use a prepolymer that is less than ol / g.

In the production method of the present invention, it is preferable to use a terminal blocking agent for controlling the terminal structure as described above. The terminal capping agent is not particularly limited as long as it is a monofunctional compound having reactivity with the amino group or carboxyl group at the polyamide terminal. Acids or monoamines are preferred, and monocarboxylic acids are more preferred, particularly from the viewpoint of easy handling. The terminal blocking agent may be added at any stage of the salt synthesis step, the prepolymer synthesis step, and the polymerization step, but is preferably added simultaneously with the diamine and dicarboxylic acid in the salt synthesis step. The amount of the terminal blocking agent added is about 0 to 10 mol% based on the starting diamine when, for example, a monocarboxylic acid is used for the purpose of controlling the degree of polymerization and the terminal structure of the obtained polyamide. It can be arbitrarily selected within the range.

The monocarboxylic acid used as a terminal blocking agent is not particularly limited as long as it has reactivity with an amino group. Examples thereof include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, and the like. Aliphatic monocarboxylic acids such as caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutylic acid; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; benzoic acid, toluic acid, α And aromatic monocarboxylic acids such as -naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid. One or more of these can be used. Among them, acetic acid, propionic acid, butyric acid,
Valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid,
Benzoic acid is preferred.

The monoamine used as the terminal capping agent is not particularly limited as long as it has reactivity with a carboxyl group. For example, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine And aliphatic monoamines such as decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine and dibutylamine; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; and aromatic monoamines such as aniline, toluidine, diphenylamine and naphthylamine. be able to. One or more of these can be used. Among them, butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline are preferable from the viewpoints of reactivity, boiling point, stability of the sealed terminal, and price.

In the present invention, in order to increase the rate of polycondensation and to prevent the polyamide formed during the polymerization from deteriorating, phosphorus-based compounds such as phosphoric acid, phosphorous acid, hypophosphorous acid or salts or esters thereof are used. Preferably, a catalyst is added to the reaction system. Among these, a hypophosphorous acid derivative, particularly sodium hypophosphite, is preferred from the viewpoint of the quality of the produced polyamide, particularly from the viewpoint of cost and ease of handling. The amount of the phosphorus-based catalyst to be added is 0.01 to 5% by weight, preferably 0.05 to 2% by weight, especially 0.05 to 2% by weight, based on the total weight of the raw materials dicarboxylic acid and diamine and the terminal blocking agent monocarboxylic acid and monoamine. 0.07-1% by weight is preferred.

The polyamide obtained by the production method of the present invention may contain, if necessary, talc, kaolin, clay, silica, alumina, titanium oxide, calcium carbonate, zinc oxide, boron nitride, mica, potassium titanate, silica Powdery fillers such as calcium oxide, magnesium sulfate, aluminum borate, wollastonite, asbestos, glass beads, carbon black, graphite, molybdenum disulfide, polytetrafluoroethylene, etc .; glass fiber, carbon fiber, polyparaphenylene terephthalamide Wholly aromatic polyamides such as fibers, polymetaphenylene terephthalamide fibers, polyparaphenylene isophthalamide fibers, polymetaphenylene isophthalamide fibers, and fibers obtained from condensates of diaminodiphenyl ether with terephthalic acid or isophthalic acid Fibers, organic fibrous fillers such as wholly aromatic liquid crystalline polyester fibers, fibrous fillers such as boron fibers; brominated polymers such as brominated polystyrene, brominated polyphenylene oxide, antimony trioxide, antimony pentoxide, antimony Flame retardants such as antimony compounds such as acid soda and metal hydroxides such as magnesium hydroxide;
Polyphenylene sulfide, molten liquid crystal polyester, syndiotactic polystyrene, aliphatic polyamide such as nylon 46, nylon 66, etc., polyolefin such as amorphous semi-aromatic polyamide, polyethylene, polypropylene, etc., polyester such as PET, PBT, polyphenylene oxide, polyether Ether ketone, polyketone,
Other polymers such as polycarbonate, polysulfone, polyethersulfone, etc .; coloring agents; ultraviolet absorbers; light stabilizers; antioxidants such as hindered phenol, thio, phosphorus and amines; crystal nuclei such as talc Agents, antistatic agents, plasticizers, release agents, lubricants, and the like.

Examples of the method for adding the above-mentioned various additives include a method for adding during the polymerization of polyamide, and a method for mixing and kneading after mixing with the obtained polyamide.

The polyamide produced as described above is
Normal melt molding methods, such as compression molding, injection molding,
Extrusion molding and the like make it possible to produce molded articles having excellent color tone without coloring.

For example, the polyamide obtained by the present invention is melted in a cylinder of an injection molding machine whose cylinder temperature is adjusted to 280 to 350 ° C., and is introduced (injected) into a mold having a predetermined shape to form a molded article. Can be manufactured. Further, a fiber can be produced by melting polyamide in an extruder adjusted to the above-mentioned cylinder temperature and spinning out from a die nozzle. Further, by melting the polyamide in an extruder adjusted to the above-mentioned cylinder temperature and extruding the polyamide from a T-die, a film or a sheet can be manufactured. Furthermore, inflation molding,
Molded articles such as films, sheets, and bottles can be manufactured by blow molding or the like.

The above-mentioned molded article can be used in a state in which a coating layer of a paint, metal, or another kind of polymer is formed on the surface.

The polyamide obtained according to the present invention includes, for example, mechanical parts such as gears and cams, electronic parts such as connectors, switches, relays, MIDs, printed wiring boards, housings for electronic parts, films, sheets, and the like. It can be used as a raw material for producing molded articles of various forms such as fibers. In particular, it can be used for applications requiring high heat aging resistance, and can be suitably used as a raw material for producing, for example, interior and exterior parts of automobiles, mechanical parts in an engine room of automobiles, and electrical parts of automobiles. Can be.

[0036]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited by these examples. In the examples, the reaction rates and terminal carboxyl groups [C
OOH], terminal amino group [NH ₂ ], color tone of the resin, hydrolysis resistance of the molded article, and heat aging resistance of the molded article were measured by the following methods.

1. Using reaction rates, [COOH] and [NH ₂ ] ¹ H-NMR (500 MHz, measured in deuterated trifluoroacetic acid at 50 ° C.), integrated values of characteristic signals of each terminal group and diamine component in the chain From the carboxyl group terminal, the amino group terminal, the sealed terminal, and the molar ratio of each diamine structural unit in the chain, the reaction rates, [COOH] and [NH ₂ ] were determined from the following formulas. Number of repeating units N = 2D / (A + B + C) Molecular weight M = (Molecular weight per repeating unit) × N Reaction rate = 4N / (4N + A + B) [COOH] = [2A / M (A + B + C)] × 1000 (mmol)
/ g) [NH ₂ ] = [2B / M (A + B + C)] × 1000 (mmol
/ g) A: molar ratio of carboxyl groups B: molar ratio of amine groups C: molar ratio of sealed ends D: molar ratio of diamine structural units in the chain

2. Color Tone of Resin The color tone of the polymer obtained by performing the melt polymerization with a twin screw extruder was visually evaluated.

3. Hydrolysis resistance A dumbbell-shaped molded product of JIS No. 2 (thickness: 2 mm) was prepared by injection molding, and it was prepared using an autoclave.
It was immersed in a 50% aqueous ethylene glycol solution at 0 ° C. for 120 hours. The tensile strength of the test piece before and after the treatment was measured according to JIS K
Measurement was performed in accordance with 7113, and the retention ratio of the strength after the treatment to the strength before the treatment was calculated.

4. Heat aging resistance A dumbbell-shaped molded product of JIS No. 2 (thickness: 2 mm) was prepared by injection molding, and the degree of coloring when treated in a gear oven at 150 ° C. for 100 hours was visually evaluated.

Example 1 3269.5 g (19.60 mol) of terephthalic acid,
2690.9 g (17.0 mol) of 9-nonanediamine,
2-methyl-1,8-octanediamine 474.9
(3.0 mol), 97.7 g (0.80 mol) of benzoic acid, 6.5 g (0.1% by weight based on the raw material) of sodium hypophosphite monohydrate and 2.2 liters of distilled water ,
The mixture was placed in an autoclave having an internal volume of 20 liters, and was replaced with nitrogen. The mixture was stirred at 100 ° C for 30 minutes, and the internal temperature was raised to 210 ° C over 2 hours. At this time, the autoclave
The pressure was increased to ² kg / cm ² . After the reaction was continued for 1 hour, the temperature was raised to 230 ° C., and then maintained at 230 ° C. for 2 hours.
The reaction was carried out while maintaining the m ² . Next, the pressure was reduced to 10 kg / cm ² over 30 minutes, and further reacted for 1 hour.
A prepolymer having the physical properties shown in Table 1 was obtained. Next, this prepolymer was dried at 100 ° C. under reduced pressure for 12 hours, and dried at 2 mm
Crushed to the following size, 25mmφ, L / D = 25,
Melt polymerization was carried out using a twin-screw extruder with two vents ("Laboplast Mill 2D25W" manufactured by Toyo Seiki Seisaku-sho, Ltd.). The cylinder temperature of the extruder was set at 330C and the resin temperature was adjusted to 325-330C. Hopper has an oxygen content of 5
Sealed with 0 ppm nitrogen gas. The first vent was opened and sealed with the nitrogen gas, and the second vent was maintained at a reduced pressure of 50 mmHg using a vacuum pump. The screw rotation speed was set to 40 rpm, and the supply amount of the prepolymer from the hopper was 1 kg / hour. The melt residence time was 4 minutes. Table 1 shows the physical properties of the obtained polymer. The melt residence time was determined by blending 0.1% of carbon black with the above prepolymer and charging the mixture in a twin-screw extruder in the same manner to carry out melt polymerization under the same conditions. It was measured by visual observation.

Example 2 Using the pulverized prepolymer obtained in Example 1,
Screw rotation speed is 100 rpm in the melt polymerization stage
Example 1 except that the melting residence time was set to 2 minutes and the melting residence time was set to 2 minutes.
Melt polymerization was carried out in the same manner as described above. Table 1 shows the physical properties of the obtained polymer.

Example 3 As a diamine component, 1,9-nonanediamine 215
Except that 2.7 g (13.6 mol), 379.9 g (2.4 mol) of 2-methyl-1,8-octanediamine, and 521.1 g (4.0 mol) of 1,6-hexanediamine were used. A prepolymer was synthesized in the same manner as in Example 1 and then subjected to melt polymerization using a twin-screw extruder to obtain a polymer.
Table 1 shows the physical properties of the prepolymer and the polymer.

Example 4 As a diamine component, 1,9-nonanediamine 158 was used.
A prepolymer was synthesized in the same manner as in Example 1 except that 2.9 g (10.0 mol) and 1302.9 g (10.0 mol) of 1,6-hexanediamine were used, and then melted by a twin-screw extruder. Polymerization was performed to obtain a polymer. Table 1 shows the physical properties of the prepolymer and the polymer.

Comparative Example 1 As raw materials, 3429.9 g (20.4 mol) of terephthalic acid and 2690.9 g of 1,9-nonanediamine (17.
0 mol), 2-methyl-1,8-octanediamine 47
The same method as in Example 1 using 4.9 (3.0 mol), 6.5 g of sodium hypophosphite monohydrate (0.1% by weight based on the raw material) and 2.2 L of distilled water. To synthesize a prepolymer, followed by melt polymerization using a twin-screw extruder to obtain a polymer. Table 1 shows the physical properties of the prepolymer and the polymer.

Comparative Example 2 As raw materials, 3627.0 g (20.0 mol) of terephthalic acid and 2744.7 g of 1,9-nonanediamine (17.
34 mol), 2-methyl-1,8-octanediamine 4
The same method as in Example 1 using 84.4 (3.06 mol), 6.5 g of sodium hypophosphite monohydrate (0.1% by weight based on the raw material) and 2.2 liters of distilled water To synthesize a prepolymer, followed by melt polymerization using a twin-screw extruder to obtain a polymer. Table 1 shows the physical properties of the prepolymer and the polymer.

Comparative Example 3 3269.5 g (19.60 mol) of terephthalic acid, 1,
2690.9 g (17.0 mol) of 9-nonanediamine,
2-methyl-1,8-octanediamine 474.9
(3.0 mol), 97.7 g (0.80 mol) of benzoic acid, 6.5 g (0.1% by weight based on the raw material) of sodium hypophosphite monohydrate and 2.2 liters of distilled water ,
The mixture was placed in an autoclave having an internal volume of 20 liters, and was replaced with nitrogen. The mixture was stirred at 100 ° C for 30 minutes, and the internal temperature was raised to 210 ° C over 2 hours. At this time, the autoclave
The pressure was increased to ² kg / cm ² . After continuing the reaction for 1 hour, the reaction vessel was rapidly cooled when the temperature was raised to 230 ° C.
A prepolymer having the physical properties shown in Table 1 was obtained. Using this prepolymer, melt polymerization was performed in the same manner as in Example 1 to obtain a polymer. Table 1 shows the physical properties of the polymer.

Comparative Example 4 Using the crushed prepolymer obtained in Example 1,
Screw rotation speed is 10 rpm in the melt polymerization stage
Example 1 except that the melting residence time was set to 20 minutes.
Polymer was obtained by melt polymerization in the same manner as described above. Table 1 shows the physical properties of the obtained polymer.

Comparative Example 5 Using the pulverized prepolymer obtained in Example 1,
Melt polymerization was carried out in the same manner as in Example 1 except that the cylinder temperature was set at 360 ° C. in the melt polymerization stage, to obtain a polymer. Table 1 shows the physical properties of the obtained polymer.

[0050]

[Table 1]

The resin codes in Table 1 are as follows. 9M-T: 1,9-nonanediamine and 2-methyl-1,
Polyamide comprising 8-octanediamine and terephthalic acid 69M-T: Polyamide comprising 1,6-hexanediamine, 1,9-nonanediamine, 2-methyl-1,8-octanediamine and terephthalic acid 69-T: 1,6 Polyamide comprising hexanediamine, 1,9-nonanediamine and terephthalic acid

[0052]

As is apparent from the above description, according to the present invention, a polyamide excellent in color tone and hydrolysis resistance can be obtained. It can be suitably used for applications requiring high hydrolysis resistance.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J001 DA01 DB01 DB04 DC14 EB05 EB06 EB07 EB08 EB09 EB13 EB14 EB36 EB37 EB46 EB55 EB56 EB60 EC08 EC09 EC13 FA01 FB03 FB05 FC03 FC05 FD01 GA12 GB02 GB06 GB12 GB16 JA01

Claims (4)

[Claims] 1. A terephthalic acid unit having a content of 60 to 100 mol%
When producing a polyamide comprising a dicarboxylic acid unit and a diamine unit containing 60 to 100 mol% of an aliphatic alkylenediamine unit having 6 to 18 carbon atoms, (1) the amino group of the raw material amine and the raw material carboxylic acid The conversion with the carboxyl group is 75% to 97%, and the terminal carboxyl group [COOH] (mmol / g) / terminal amino group [NH ₂ ] (mmol
/ g) is 150/100 to 50/100, and [COO
A prepolymer having an absolute value of [H]-[NH ₂ ] of 0.2 mmol / g or less is prepared, and then (2) the prepolymer is treated at a temperature of 350 ° C. or less and a melt residence time of 5 minutes or less. The reaction rate between the amino group of the raw material amine and the carboxyl group of the raw material carboxylic acid is 98% or more, and the terminal carboxyl group [COOH] is 0.2 mmol.
A method for producing a polyamide, characterized in that a polyamide having a terminal amino group [NH ₂ ] of 0.2 mmol / g or less is obtained. 2. The method according to claim 1, wherein the aliphatic alkylenediamine unit having 6 to 18 carbon atoms is an aliphatic alkylenediamine unit having 6 to 9 carbon atoms. 3. The aliphatic alkylenediamine unit having 6 to 18 carbon atoms is at least one selected from the group consisting of 1,9-nonanediamine unit and 2-methyl-1,8-octanediamine unit. The manufacturing method as described. 4. The prepolymer is fed to a twin-screw extruder at 340.
The production method according to any one of claims 1 to 3, wherein melt polymerization is performed at a temperature of not more than ℃.