JPS61228022A - Production of polyamide - Google Patents

Abstract

PURPOSE:To obtain a polyamide having excellent heat-resistance, strength and moldability, by heating an oligocondensate of an aromatic dicarboxylic acid component and an alkylenediamine component having a specific composition under specific condition in molten state under shearing and carrying out the thermal polycondensation in solid state. CONSTITUTION:[A] An oligocondensate is produced from an aromatic dicarboxylic acid component unit (composed of 60-100mol% terephthalic acid component and 0-40mol% other aromatic dicarboxylic acid component) and an alkylenediamine component unit (6-18C aliphalic alkylenediamine compo nent). The oligocondensate is heated in molten state at <=Tm150 deg.C (Tm is melting point) under shearing force using a kneading means to form a prepolymer [B]. The objective polyamide [C] can be produced by the polycondensation of the prepolymer [B] by heating in solid phase at Tm-150 deg.C. The intrinsic viscosity of the oligocondensate [eta]A and that of the prepolymer [eta]B measured in concen trated sulfuric acid at 30 deg.C satisfy the formulas I-III, and the intrinsic viscosity [eta]C of the polyamide measured in concentrated sulfuric acid at 50 deg.C satisfies the formulas IV and V.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a molding material that has excellent performance in all of heat resistance properties, mechanical properties, chemical and physical properties, and moldability, especially for sliding properties. This invention relates to a method for producing polyamide with excellent properties.

[Conventional technology]

Generally polyolefin, polyester.

Thermoplastic resins such as polyamide are compression molded.

Melt molding such as injection molding or extrusion molding can be performed, although moldability is poor.

Heat resistance properties 1 Neither mechanical properties nor chemical properties are satisfactory as engineering plastics.

They are used in various general-purpose molding fields by taking advantage of their respective characteristics.

Conventionally, polytetrafluoroethylene (Teflon ■) has been used as an engineering plastic with excellent heat resistance, mechanical properties, and chemical and physical properties.

Polyhexamethylene adipamide (6,6-nylon)
, poly2,4.4-trimethylhexamethylene terephthalamide (Trogamide ■), polyacetal, polyphenylene sulfide, and the like are known. Among these, polytetrafluoroethylene has excellent heat resistance properties, mechanical properties, and chemical and physical properties, but has the disadvantage that it cannot be melt-molded, and its field of use is severely limited. Also among these engineering plastics.

Polyhexamethyleneazibomide (6,6-nylon).

2.4.4-) IJ Methylhexamethylene terephthalamide (Trogamide T), boriacedal, polyphenylene sulfide, etc. all have the characteristic of being able to be melt-molded, but all of these polyamides have a glass transition point. , heat resistance properties such as heat distortion temperature, tensile properties 1 mechanical properties such as bending strength, critical pv value, abrasion resistance, and chemical resistance.

It has poor chemical and physical properties such as boiling water resistance and saturated water absorption,
Polyacetal has disadvantages such as poor heat resistance properties such as melting point and heat distortion temperature, and poor mechanical properties such as bending strength, impact strength, and abrasion resistance.

In particular, it is not suitable for use as a molding material for sliding materials that requires heat resistance and has excellent sliding properties.

The present inventors investigated a molding material that has excellent performance in heat resistance properties 1 mechanical properties, chemical and physical properties, and moldability, and in particular a molding material for sliding materials that has excellent sliding properties. As a result, it was found that a specific polyamide consisting of an aromatic dicarboxylic acid component unit whose main component is a terephthalic acid component potential and an alkylene diamine component potential is excellent in the above-mentioned performance. However, conventionally, this polyamide has been mainly produced by a method of polycondensing a corresponding aromatic dicarboxylic acid civalide and an alkylene diamine in the presence of a base, but in this method, the aromatic dicarboxylic acid civalide is expensive, and the polyamide is could not be manufactured economically.

In addition, as another method, an alkylene diamine salt of an aromatic dicarboxylic acid or a lower condensate thereof, which is formed from a corresponding aromatic dicarboxylic acid and an alkylene diamine component potential, is heated under melting conditions to undergo polycondensation. A method is also known, and is an industrially excellent method. However, this method causes thermal decomposition because the polyamide has a high melting point and requires high temperatures to maintain its molten state, and the polyamide produced using this method has strong mechanical strength, sliding properties, and heat deterioration resistance.

The color tone was poor and it was insufficient for use in the above-mentioned applications. Furthermore, the polyamide obtained by this method has drawbacks such as high viscosity and difficulty in handling.

On the other hand, JP-A-59-161428 and JP-A-5
9-155426 discloses a lower condensate formed from an aromatic dicarboxylic component position and an alkylene diamine component unit, an aromatic dicarboxylic acid component site, an alkyl diamine component position, and an aliphatic dicarboxylic acid component. A method has been proposed in which a low-order condensate formed from units is subjected to a polycondensation reaction using a melt extruder. Although this method can shorten the polycondensation time and produce a polyamide with an excellent color tone, the molecular weight cannot be sufficiently increased because one reaction time is insufficient. II It was inferior in physical properties such as mechanical strength and heat aging resistance, and sufficient performance could not be obtained even when used for the above purpose.

[Problem that the invention seeks to solve]

The present inventors have produced a polyamide with excellent mechanical strength, sliding properties, heat aging resistance, and one color tone from a low-order condensate formed from an aromatic dicarboxylic acid component potential and an alkylene diamine component unit. As a result of studying a method to do this, it was found that a lower-order condensate formed from an aromatic dicarboxylic acid component potential of a specific composition and an alkylene diamine component unit is heated under specific conditions in a molten state using a cross-wire means under shear conditions. 1) It was discovered that the above object could be achieved by polycondensing the product by heating it in a solid state, and 1) the present invention was achieved.

〔Effect of the invention〕

The polyamide produced by the production method of the present invention has heat resistance properties such as melting point, glass transition point and heat distortion temperature, heat aging resistance, tensile strength 1 bending strength, impact strength, coefficient of dynamic friction,
Mechanical properties such as limit pv value and taper wear, especially mechanical strength and sliding properties.

Excellent chemical and physical properties such as heat aging resistance, chemical resistance, boiling water resistance, and saturated water absorption, as well as moldability such as fluidity of melt compositions, melt compression moldability, melt injection moldability, and melt extrusion moldability. It has the characteristic of being

Furthermore, the method of the present invention is a manufacturing method that is superior in industrial implementation compared to conventional methods, and is characterized in that the polyamide can be manufactured at low cost.

[Means for Solving the Problems] and [Operation] The present invention provides a lower condensate [A] formed from an aromatic dicarboxylic acid component unit (a) and an alkylene diamine component unit (b) in a molten state. The prepolymer [B] was heated under shearing conditions using a crossing means, and then the prepolymer C was prepared.
B: A method for producing polyamide [c] by heating in a Te solid phase state and carrying out single polycondensation.

(1) The aromatic dicarboxylic acid component moiety (a) has a terephthalic acid component moiety in a range of 60 to 100 mole arcs and an aromatic dicarboxylic acid component unit other than terephthalic acid component units in a range of 0 to 40 moles/1%. and the alkylene diamine component unit rb) has 6 to 1 carbon atoms.
Must be an aliphatic alkylene diamine component unit.

(11) The lower condensate [A] and the prepolymer [B]
] was measured in concentrated sulfuric acid at 30°C.
Let η]C and [η]B.

[η]A≦0.6dl/g O, 5al/g≦[η]B and [η]B/[η]A≧1.1, and the polyamide [c] is made of concentrated sulfuric acid at 50°C. or a polyamide containing the insoluble polyamide, or a polyamide soluble in 50"C concentrated sulfuric acid, and when the polyamide [C] is a concentrated sulfuric acid soluble polyamide, its intrinsic viscosity [η] If it is C.

[η]C20.6617g and [η]C/[η]B21.1 are satisfied, and +il+> The heating temperature in the molten state [T1] is the temperature at which the polycondensation reaction mixture melts or the melting point plus 150"C
The temperature should be within the following temperature range, and the heating temperature [T2] in the solid state should be 150-C lower than the melting point of the polycondensation reaction mixture or below the melting point.

The gist of this paper is a method for producing polyamide with all the characteristics.

The lower condensate [A] formed from the aromatic dicarboxylic acid component unit (a) and the alkylene diamine component unit (b) used as raw materials in the single polycondensation reaction in the method of the present invention is It is formed from an acid component unit (a) and an alkylene diamine component unit (b). The lower-order condensate is prepared by combining an aromatic dicarboxylic acid and an alkylene diamine, a salt thereof, or an aromatic dicarboxylic acid ester and an alkylene diamine in the presence of a solvent such as water, alcohol, phenol, or aromatic hydrocarbon as necessary. Normally 120 to 350°C
, “preferably by heating to 200 to 300°C.

generate. Among these lower condensates, a method using the aromatic dicarboxylic acid and an alkylene diamine or a salt thereof is preferred, and in particular, when they are reacted in the presence of an aqueous solvent in an autoclave, the color tone of the lower condensate produced is It is preferable because it has advantages such as excellent performance, easy extraction, and easy handling. When producing the lower-order condensate, catalysts such as sodium phosphoric acid monohypophosphite, octyl phosphate, and tristridecyl phosphite, stabilizers, and the like may be added. The intrinsic viscosity [η] of the lower condensate measured at 30°C in concentrated sulfuric acid must be in the range of 0.66e/g or less, preferably 0.01 to 0.45°, particularly preferably 0.03 to 0.30dJ? /g range. Its melting point usually ranges from 200 to 640°C. Is [η] of the lower condensate 0.6dj? /gfl
- If the temperature is exceeded, the manufacturing conditions (temperature for 1 hour, etc.) of the low-order condensate will become strict, and the color tone and extraction method of the low-order condensate will become difficult, as well as the color tone and heat resistance of the resulting polyamide. Physical properties such as aging properties begin to deteriorate significantly.

Aromatic dicarboxylic acid component unit (a) used as a raw material in the single polycondensation reaction in the method of the present invention? The aromatic dicarboxylic acid component unit (a) constituting the lower condensate formed from -5 and the alkylene diamine component unit (b) has a range of 60 to 100 mol% of the terephthalic acid component unit and an aroma other than the terephthalic acid component unit. It is a lower condensate consisting of an aromatic dicarboxylic acid component unit (a) containing 0 to 40 mol % of group dicarboxylic acid component units and an aliphatic alkylene diamine component unit having 6 to 1 B carbon atoms (b).

In the polycondensation reaction of the method of the present invention, the aromatic dicarboxylic acid component units (,) constituting the lower condensate used as raw materials include terephthalic acid, isophthalic acid, phthalic acid, 2-methyl Examples of each component unit include terephthalic acid and naphthalene dicarboxylic acid.

The composition of the aromatic dicarboxylic acid component unit Ta) may be a single terephthalic acid component unit, but it is a mixture of a terephthalic acid component unit and the above-mentioned aromatic dicarboxylic acid component units other than the terephthalic acid component unit. Good too. In either case, the composition of the aromatic dicarboxylic acid component unit (a) constituting the lower condensate is 60 terephthalic acid component units.
Aromatic dicarboxylic acid component units other than terephthalic acid component units ranging from 0 to 100 mol% and 0 to 40 mol%
It is necessary to consist of a range of . Further, the composition of the aromatic dicarboxylic acid component unit (a) is, when the aliphatic alkylene/diamine component unit (b) constituting the lower-order composite is an aliphatic alkylene diamine having 6 carbon atoms, the composition is a terephthalic acid component unit. is in the range of 60 to 85 mol% and aromatic dicarboxylic acid component units other than terephthalic acid component units are 15
1. Heat resistance properties such as heat distortion temperature of polyamide produced by the method of the present invention,
It is particularly preferable because mechanical properties such as tensile strength 1 bending strength, sliding properties, moldability, etc. are improved. Further, when the aliphatic alkylene diamine component unit (b) constituting the lower condensate is an aliphatic alkylene diamine having 8 carbon atoms.

When the terephthalic acid component units are in the range of 65 to 100 mol% and the aromatic dicarboxylic acid component units other than terephthalic acid component units are in the range of 0 to 65 mol%, the heat distortion temperature etc. of the polyamide produced by the method of the present invention is It is particularly preferable because heat resistance properties, mechanical properties such as tensile strength 1 bending strength, sliding properties, moldability, etc. are improved. Also.

When the aliphatic alkylene diamine component unit (b) constituting the lower condensate is an aliphatic alkylene diamine having 10 to 18 carbon atoms, 75 to 1 terephthalic acid component unit
00 mol% and aromatic dicarboxylic acid component units other than terephthalic acid component units in the range of 0 to 25 mol% (1) Heat resistance properties such as heat distortion temperature, tensile strength (1) of polyamide produced by the method of the present invention Mechanical properties such as bending strength.

This is particularly preferred since it improves sliding properties and moldability. The composition of the aromatic dicarboxylic acid component unit (a) is such that the terephthalic acid component unit is less than 60 mol% and the aromatic dicarboxylic acid component unit other than the terephthalic acid component unit is 40% by mole.
If it is larger than mol%, the heat resistance properties such as heat distortion temperature of polyamide, mechanical properties such as tensile strength 1 bending strength, etc.
Chemical and physical properties such as sliding properties, chemical resistance, and water resistance deteriorate. Among the aromatic dicarboxylic acid component units other than the terephthalic acid component unit of the aromatic dicarboxylic acid component unit (a) constituting the lower condensate, isoyi
It is preferably an AJla minute unit or a naphthalene dicarboxylic acid component unit, and particularly preferably an isophthalene brewing component unit. Further, the aromatic dicarboxylic acid component unit (a) constituting the lower condensate is mainly composed of a terephthalic acid component unit and the aromatic dicarboxylic acid component unit other than the terephthalic acid component unit. ,
In addition to the above-mentioned essential components, a small amount (for example, about 10 mol%) of aliphatic dicarboxylic acid component units such as adipic acid and sebacic acid, and tribasic or higher polyhydric carboxylic acid components such as trimellitic acid and bitemarellitic acid are added. It is okay to include units.

The aliphatic alkylene diamine component unit (b) constituting the lower condensate [A] used as a raw material for the polycondensation reaction in the method of the present invention is an aliphatic alkylene diamine having 6 to 1 B carbon atoms, and specifically Specifically, 1,4-diamino-1,1-dimethylbutane, 1゜4-diamino-1-
Ethylbutane, 1,4-diamino-1,2-dimethylbutane, 1,4-diamino-1,3-dimethylbutane, 1
．． 4-diamino-1,4-dimethylbutane, 1,4-diamino-2,3-dimethylbutane.

1.2-diamino-1-butylethane, 1.6-diethylhexane, 1.7-diaminohbutane, 1.8-diaminooctane, 1.6-diamino-2,5-dimethylhexane, 1.6-diamino-2 .4-Dimethylhexane, 1,6-diamy2-3,3-dimethylhexane, 1゜6-diamy2,2-dimethylhexane, 1,9-diaminononane, 1,6-diamy2,2,4-)limethyl Hexane, 1,6-Diami2.4.4-) Diethylhexane, 1.7-Diami2, 2.3-Dimethylhebutane, 1.7-Diami2, 2.4-Dimethylhebutane, 1°7-Diami2. 5-dimethylhebutane, 1
．． 7-Diami2,2-dimethylhebutane,! , 10
-diaminodecane, 1,8-diamino-1,3-dimethyloctane, 1,8-diamino-1,4-dimethyloctane, 1°8-diamino-2,4-dimethyloctane,
1,8-diamino-6,4-dimethyloctane, 1.8
-Diamino-4,5-dimethyloctane, 1,8-diamino-2゜2-dimethyloctane, 1,8-diamino-
3,3-dimethyloctane, 1,8-diamino-4,4
-dimethyloctane, 1,6-diamino-2,4-diethylhexane, 1,9-diamino-5-methylnonane,
Examples of each component unit include 1.11-diaminoundecane and 1.12-diaminododecane. Among these aliphatic alkylene diamine component units (b), 1.6-diamithexane component units, 1.8-diaminooctane component units, 1.10-diaminodecane component units, and 1.12-diaminododecane component units. unit or a mixed component unit thereof, particularly 1,6
- It is preferable that it is a siamitsuhexane component unit.

In the method of the present invention, the aromatic dicarboxylic acid component unit (a) and the aliphatic alkylene diamine component unit 1b)
In the polymerization reaction of the lower condensate [A] formed from It is carried out by heating in phase state. As the kneading means under shear conditions used in the production of the prepolymer [B], any method capable of kneading a high viscosity polymer under heating conditions can be adopted, and specifically, rolls, extrusion, etc. Examples include a machine and a kneader. Among these methods, it has the advantages of being able to easily knead at high temperatures, being able to form a prepolymer in a short time, and being able to easily prepare the prepolymer by hand. A method using an extruder, kneader, etc. is preferred. As an extruder, a single-screw or multi-screw extruder with a vent that can distill off water etc. from the reaction distillate can be used, and the reaction product can be produced from the vent under normal pressure (pressure) or reduced pressure. By distilling off the substance, it can be easily removed under melting conditions for a short period of time (
Prepolymer [B] can be produced within 10 minutes or less (usually within 10 minutes). [η] of prepolymer [B] ([η
) 8. Value measured in concentrated sulfuric acid at 50°C) is 0.3 dl/
It is necessary that the value is greater than or equal to g, preferably 0.4
The range is from 1.4 dl/g to 1.4 dl/g, particularly preferably 0.0 dl/g. It is preferably in the range of 1.2 to 1.2 d#/g. Further, the value of the ratio [η]B/[η]6 between [η]B of the prepolymer [B) and [η] ([η]A) of the lower-order condensate is 1
．． It is necessary that the number is 1 or more, preferably 2.0 or more, and particularly preferably in the range of 3 to 50. [η]B of prepolymer [B] is 0jdl/
If the value of [η]B/[η is less than 1.1, the molecular weight of the obtained polyamide is insufficient, and the mechanical properties such as the tensile strength and bending strength of the polyamide are It is necessary to significantly increase the molecular weight through solid phase polymerization in order to deteriorate the sliding properties or to develop sufficient strength, which requires harsh solid phase polymerization conditions, resulting in poor color tone of polyamide. Heat aging resistance etc. begin to deteriorate.

In addition, the heating temperature [T,] when producing the prepolymer [B] needs to be a temperature below the melting temperature of the polycondensation reaction mixture or a temperature higher than the melting point by 150"C, preferably a temperature at which the polycondensation reaction mixture melts. No temperature L [a plus 10
Preferably, the temperature is below 0°C. The heating temperature [T1] is 150"C from the melting point of the polycondensation mixture
At higher temperatures, the color tone and heat aging resistance of prepolymers and polyamides decrease.

Further, in the solid phase polycondensation, the prepolymer [B
] is heated in the same phase to polycondense the polycondensation reaction mixture. The temperature must be 150°C lower or lower than the melting point of the polycondensation reaction mixture, preferably 14°C lower than the melting point.
oc low temperature or a temperature range 30°C lower than the melting point,
More preferably, the temperature is 120°C lower than the melting point to 40°C lower than the melting point.

The polyamide CC) produced by the method of the invention is 5
A polyamide that is insoluble in concentrated sulfuric acid at 0 °C, a polyamide containing the insoluble polyamide, or a polyamide soluble in concentrated sulfuric acid at 50 °C, and the polyamide [c
] is a polyamide soluble in concentrated sulfuric acid, and if its intrinsic viscosity measured in concentrated sulfuric acid at 30°C is [η]C,
[η]C is required to be 0.6 dl/g or more, preferably 1.0 d (17 g or more, particularly preferably 1.3 dl/g or more. of [η) ((η)B) Tonnage ratio [η]C/[η]B
must be 1.1 or more, preferably 1.
It is 3 or more, particularly preferably 1.5 or more. The polyamide [C] is a 50”C polyamide soluble in concentrated sulfuric acid, and [η]C is less than 0.6 dl/g or the value of [η]C/[η]B is less than 1.1. In this case, mechanical strength such as tensile strength 1 bending strength, sliding properties, etc. of the polyamide (CC) deteriorate.

If the polyamide CC) is a composition consisting of a 50-C polyamide insoluble in concentrated sulfuric acid and a 50"C polyamide soluble in concentrated sulfuric acid, the ratio is not particularly limited, but preferably the polyamide soluble in concentrated sulfuric acid 2 to 10 parts of the concentrated sulfuric acid-insoluble polyamide per 100 parts by weight
00 parts by weight, particularly preferably from 5 to 400 parts by weight.

The polyamide obtained by the method of the present invention has the above-mentioned excellent performance and is used as a variety of molding materials.In addition to its excellent performance as a sliding material, it is also used as a coater/agent and an adhesive. , and used for various other purposes. The polyamide may contain conventionally known polymer stabilizers, plasticizers, and mold release agents, if necessary.

Examples include lubricants and fillers. As a polymer, nylon 6.6. Examples include polyamides such as nylon 6. Fillers are available in powder form, plate form,
! It is an organic or inorganic compound having various forms such as fibrous or cross-like substances, and specifically, silica, alumina, silica alumina, talc, diatomaceous earth,
Powdered and plate-like inorganic compounds such as clay, kaolin, quartz, glass, mica, graphite, molybdenum disulfide, gypsum, red iron oxide, tin dioxide, aluminized MtEz, fluminilum, copper, and stainless steel, and glass fiber.

Fibrous inorganic compounds such as carbon fiber, boron fiber, ceramic fiber, asbestos fiber, and stainless steel fiber, or secondary processed products such as cross-shaped products thereof, polyparaphenylene terephthalamide.

Polymetaphenylene terephthalamide, polyparaphenylene isophthalamide, polymetaphenylene isophthalamide, diaminodiphenyl ether and terephthalic acid (
isophthalic acid).

Fully aromatic polyamides such as condensates of p(m)-aminobenzoic acid, fully aromatic polyamideimides such as condensates with diaminodiphenylnitrate trimellitic anhydride or pyromellitic anhydride, fully aromatic polyimides Examples include heterocyclic-containing compounds such as polybenzimidazole and polyimidazophenanthroline, and secondary processed products of these such as powdered, plate-like, 1a fiber-like or cross-like products such as polytetrafluoroethylene. Yes, these 2
It is also possible to use a mixture of ridges or more. These fillers treated with silane couplers, titanium couplers, etc. can also be used.

Among the fillers, powder fillers include silica, silica alumina, alumina, and titanium dioxide.

It is preferable to use graphite, molybdenum disulfide, or polytetrafluoroethylene, and in particular, when graphite, molybdenum disulfide, or polytetrafluoroethylene is used, the coefficient of kinetic friction of the molded article obtained from the composition is
This is preferable because it improves wear resistance such as taper wear and limit pv value. The average particle size of such fillers is usually in the range of 0.1 mμ to 200 μm, particularly preferably in the range of 1 mμ to 100 μm, since the above-mentioned wear resistance is significantly improved. The blending ratio of such a filler is usually in the range of 200 parts by weight exceeding 0 to 1 part by weight of the polyamide, preferably 1 part by weight exceeding 0.
00 parts by weight, particularly preferably 0.5 to 50 parts by weight
Parts by weight range.

Further, among the fillers, examples of organic fibrous fillers include polybaraphenylene terephthalamide tan and polymetaphenylene terephthalamide fiber.

The use of wholly aromatic polyamide fibers such as polyvara 7-ethylene iso-7-talamide Im fiber, darimetaphenylene iso-7-talamide fiber, fiber obtained from a condensate of diaminodiphenyl ether and terephthalic acid * G1 isophthalic acid, etc., can be used to improve the composition. The tensile strength of the molded body obtained from
This is preferable because mechanical properties such as Izot impact strength and heat resistance properties such as heat distortion temperature are improved. moreover.

Among the above fillers, when glass fiber, carbon fiber or boron fiber is used as the #a-free fibrous filler, the molded article obtained from the composition has a tensile strength of 1 flexural strength of 1
Mechanical properties such as flexural modulus.

This is preferable because heat resistance properties such as heat distortion temperature, chemical and physical properties such as water resistance, etc. are improved. When the average length of the organic or inorganic fibrous filler is generally in the range of 0.1 to 20 mm, particularly in the range of 1 to 10 mm, the moldability of the composition is improved and the composition can be obtained from the composition. Heat resistance properties such as heat distortion temperature, tensile strength 1 of molded bodies
This is preferable because mechanical properties such as bending strength are improved. The blending ratio of the organic or inorganic fibrous filler is usually in the range of more than 0 to 200 parts by weight based on 100 parts by weight of the polyamide.

The range is preferably from 5 to 180 parts by weight, particularly preferably from 5 to 150 parts by weight.

The polyamide produced by the method of the invention can be molded by conventional melt molding, such as compression molding, injection molding or extrusion molding.

〔Example〕

Next, the polyamide composition of the present invention will be specifically explained with reference to Examples. The method for preparing the test piece and the evaluation method for each performance are shown below.

Further, the following abbreviations used in Table 1 below indicate the following compounds, respectively.

TA: Terephthalic acid A: Isophthalic acid C6DA = 1.6-diamithexane (Preparation of test piece and evaluation method of each physical property) Polyamide was crushed with a crusher (32 mesh passes) L, 10
After drying for 12 hours at 0℃s lmmHg, the polyamide was molded at 100kt in a nitrogen atmosphere using a press molding machine.
After hot pressing at a temperature of 20° C. above the melting point of the concentrated sulfuric acid-soluble polyamide under a pressure of i/cm 2 , cold pressing was performed at a temperature of 20° C.

Compression molded plates with a thickness of 2 mm to 10 mm were produced. After cutting these molded plates to the dimensions of each test piece listed in Table 1, they were heated at 96°C in an atmosphere at a temperature of 23°C and a relative humidity of 65%.
After being left for hr, it was subjected to a test.

In addition, the glass fiber compound product consists of a predetermined amount of crushed and dried polyamide and a predetermined amount of glass fiber (average length 6aH1, Nittobo KK 11.Chopped Strand C86pE-2).
31) was supplied to a -shaft extruder (L/D=28.20 mmφ) and mixed to obtain a strand shape of 8 to ID mm. The test piece was prepared in the same manner as when no glass fiber was mixed.

Example 1 Terephthalic acid 123.6g (0.7a4M), isophthalic acid 52.9g (0.518M). 123.4 g (1,062 M) of hexamethylene diamine and 74 g of ion-exchanged water were placed in a No. 14 autoclave, and after sufficient N2 substitution, the temperature was raised to 250° C. over 2 hours with stirring.

After further allowing the reaction to proceed for 1 hour at 250°C in a tightly packed state, stirring was stopped and a differential pressure of 1Q was applied from the bottom of the autoclave.
The reaction mixture was removed at kti/cm. 100℃ in N2
, and dried overnight at 100 mmHg to obtain a lower condensate. This lower-order condensate [η] (in concH2S04).

30℃) is 0.1clj? /g. This low-order condensate was processed using a twin-screw extruder (screw diameter 30 mm, L/D = 42
．． Barrel temperature ("C) 50/260/2BO1500/
600/320/320/34015sO/3aO, 4th. Zone 6 is vented to the atmosphere, zone 8 is 93m
mHg vacuum.

Rotation speed 80 rpm, oligomer supply amount 2 kQ/hr
, exhaust is N2 barge) to proceed with melting condensation (
The temperature of melt polymerization in the extruder was always kept below a temperature 90"C higher than the melting point of the polycondensation reaction mixture) [η] was 0.
．． 7061/g (conc FI2HO4, 30℃
), a prepolymer with a melting point of 320'017) was obtained. This prepolymer was subjected to solid phase polymerization for 3 hours under the conditions of 250-C and lmmHg, and [η] was 1-40'l.
/ g (in cone H2804, 50°C), melting point is 3
A polyamide at 50°C was obtained. The temperature during solid phase polymerization is always between 8'0°C and 70°C lower than the melting point of the polycondensation reactant.
The temperature was kept low. The physical properties of this polyamide are shown in Table 2.

Example 2 Synthesis of the lower condensate in Example 1 was carried out using 74% ion-exchanged water.
A polyamide was synthesized by the method described in Example 1, except that 128 g was used instead of tt.

The results are shown in Table 2.

Example 3 Polyamide was synthesized by the method described in Example 2, except that instead of synthesizing the lower-order condensate using 74 g of ion-exchanged water at 250°C in Example N1, it was carried out at 280"C using 26g of ion-exchanged water. The results are shown in Table 2.

Example 4 In Example 1, when producing a prepolymer from a low-order condensate using a twin-screw extruder, the degree of vacuum in the 8th zone was set to 90
PolyJ amide was synthesized by the method described in Example 1, except that lmmHg was used instead of mmHg. The results are shown in Table 2.

Example 5 In Example 14, the amounts of terephthalic acid and isophthalic acid used were 1'52.5g (0,797M) and 44g, respectively.
．． A lower condensate was synthesized in place of 1g (0,266M).

In addition, the nozzle temperature ("C) of the twin screw extruder when synthesizing the prepolymer was set to 50/270/2801500/300.
Poly-11 amide was synthesized by the method described in Example 4, except that Brevo 11-mer was synthesized in place of 1520/3501560/350/350. The results are shown in Table 2.

Example 6 A polyamide was synthesized by the method described in Example 4, except that the solid state polymerization temperature and time of the prepolymer were changed to 2BO"C and 8 hr. The results are shown in Table 2.

Example 7 Example except that 500 g of nylon salt of terephthalic acid and decamethylene diamine and 128 g of ion-exchanged water were used instead of using terephthalic acid, isophthalic acid, and hexamethylene diamine as raw materials for the lower condensate in Example 1. Polyamide was synthesized by the method described in 1. The results are shown in Table 2.

Example Day A glass fiber blended product was prepared from 100 parts by weight of the polyamide described in Example 1 and 66 parts by weight of glass fiber, and its physical properties were evaluated. The results are shown in Table 2.Comparative Example 1 In Example 1, the amounts of terephthalic acid and isophthalic acid used were changed to 109.4 g and 67.1 g, respectively, and a lower condensate was synthesized. Polyamide was synthesized using the method described below. The results are shown in Table 2.

Comparative Example 2 In Example 4, the prepolymer was used as a polyamide and its physical properties were investigated without performing solid phase polymerization of the prepolymer. The results are shown in Table 2.

Comparative Example 3 A polyamide was synthesized in the same manner as in Example 1, except that the manufacturing conditions for producing the low-order condensate were changed as follows. In other words, one reaction wet carbon is heated at 250°C for 2 hours.
The mixture was allowed to react for 1 hour. After that, the temperature was raised to 280℃, and the pressure was gradually depressurized over an hour to maintain the internal temperature at this temperature.
When the pressure reached 151 tQ/32, the temperature was raised to 530°C and returned to atmospheric pressure.

Claims (1)

[Claims] (1) The lower condensate [A] formed from the aromatic dicarboxylic acid component unit (a) and the alkylene diamine component unit (b) is heated in a molten state using a kneading means under shear conditions to form a prepolymer. [B], and then heating the prepolymer [B] in a solid state to cause polycondensation to produce polyamide [c], the method comprising: (i) the aromatic dicarboxylic acid component unit (a ) consists of 60 to 100 mol% of terephthalic acid component units and 0 to 40 mol% of aromatic dicarboxylic acid component units other than terephthalic acid component units, and the alkylene diamine component unit (b) has 6 carbon atoms. to 18 aliphatic alkylene diamine component units; (ii) the lower condensate [A] and the prepolymer [B];
] was measured in concentrated sulfuric acid at 30°C.
If η]_A and [η]_B, then [η]_A≦0.
6dl/g 0.3dl/g≦[η]_B and [η]_B/[η]_A≧1.1, and the polyamide [c] is a polyamide that is insoluble in concentrated sulfuric acid at 50°C, or If it is a polyamide containing an insoluble polyamide or a polyamide soluble in concentrated sulfuric acid at 50°C, and if the polyamide [c] is a polyamide soluble in concentrated sulfuric acid, and its intrinsic viscosity is [η]_C, then [η]_C ≧0.6 dl/g and [η]_C/[η]_B≧1.1, and (iii) the heating temperature in the molten state [T_1] is the temperature at which the polycondensation reaction mixture melts or the melting point plus The temperature range is 150°C or less, and the heating temperature [T_2] in the solid state is 15% from the melting point of the polycondensation reaction mixture.
A method for producing polyamide, characterized in that the temperature is 0°C lower or below the melting point.