JPH0645683B2 - Method for producing polyamide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a molding material having excellent performance in heat resistance, mechanical properties, chemical / physical properties, and moldability, especially sliding. The present invention relates to a method for producing a polyamide having excellent properties.

[Conventional technology]

Generally, thermoplastic resins such as polyolefin, polyester and polyamide can be melt-molded such as compression molding, injection molding or extrusion molding, and they have excellent moldability, but have heat resistance, mechanical properties and chemical properties. Not all of these performances are satisfactory as engineering plastics, and they are used in their respective general-purpose molding fields by taking advantage of their respective characteristics.

Conventionally, in heat resistance characteristics, mechanical characteristics and chemical / physical characteristics
As an excellent engineering plastic,
Trafluoroethylene (Teflon ), Polyhexamethyle
Nazipoamide 6,6-nylon), poly 2,4,4-trimethyl
Lehexamethylene terephthalamide (trogamide ),
Known for polyacetal, polyphenylene sulfide, etc.
Has been. Of these, polytetrafluoroethylene is
Excellent heat resistance, mechanical and chemical-physical properties
However, it has the drawback that it cannot be melt-molded.
However, their fields of use are extremely limited. Also this
Of these engineering plastics,
Xamethylene adipamide (6.6-nylon), 2,4,4-to
Limethylhexamethylene terephthalamide (trogamide
T ), Polyacetal, polyphenylene sulfide
The characteristics that both can be melt-molded
However, all of these polyamides have a glass transition point,
Heat resistance such as heat distortion temperature, tensile properties, bending strength, limits
Mechanical properties such as PV value, wear resistance, chemical resistance, resistance
Poor chemical and physical properties such as boiling water and saturated water absorption,
Reacetal has heat resistance characteristics such as melting point and heat distortion temperature, and
Poor mechanical properties such as bending strength, impact strength, and abrasion resistance
Each has its own drawbacks, and is it particularly required to have heat resistance?
Suitable for use as a molding material for sliding materials with excellent sliding characteristics
Not in.

The present inventors have investigated a molding material having excellent heat resistance characteristics, mechanical characteristics, chemical-physical characteristics, and moldability, in particular, a molding material for sliding materials having excellent sliding characteristics. As a result, it was found that a specific polyamide composed of an aromatic dicarboxylic acid component unit and an alkylenediamine component unit containing a terephthalic acid component unit as the main component is excellent in the above performance. However, conventionally, this polyamide was mainly produced by a method of polycondensing a corresponding aromatic dicarboxylic acid dihalide and alkylenediamine in the presence of a base, but in this method, the aromatic dicarboxylic acid dihalide is expensive, It has not been possible to produce polyamides economically. As another method, a method of heating an alkylenediamine salt of an aromatic dicarboxylic acid or a lower condensate of the aromatic dicarboxylic acid formed from a corresponding aromatic dicarboxylic acid component unit and an alkylenediamine component unit to perform polycondensation by heating under melting conditions is also available. It is a known and industrially superior method. However, in this method, the melting point of the polyamide is high, which causes thermal decomposition because it requires a high temperature to maintain a molten state, and the polyamide produced by this method has poor mechanical strength, slidability, heat deterioration resistance, and color tone, It was insufficient for use in the above-mentioned applications. In addition, 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-59-155426 disclose that a low-order condensate or an aromatic dicarboxylic acid component unit formed from an aromatic dicarboxylic acid component unit and an alkylenediamine component unit. A method has been proposed in which a low-order condensate formed from an alkylenediamine component unit and an aliphatic dicarboxylic acid component unit is subjected to a polycondensation reaction using a melt extruder. In this method, reduction of the polycondensation time can be achieved, and a polyamide having an excellent color tone is produced, but the reaction time cannot be sufficiently taken so that the molecular weight is not sufficiently improved,
It was inferior in physical properties such as mechanical strength and heat aging resistance, and sufficient performance could not be obtained even if it was used for the above-mentioned purpose.

[Problems to be solved by the invention]

The present inventors produced a polyamide having excellent performance in mechanical strength, sliding properties, heat aging resistance, color tone, etc. from a low-order condensate formed from an aromatic dicarboxylic acid component unit and an alkylenediamine component unit. As a result of investigating the method, a low-order condensate formed from an aromatic dicarboxylic acid component unit and an alkylenediamine component unit of a specific composition is heated in a molten state under specific conditions by using a kneading means. Then, they have found that the above object can be achieved by heating and then polycondensing in a solid phase state, and arrived at the present invention.

〔The invention's effect〕

The polyamide produced by the production method of the present invention has heat resistance characteristics such as melting, glass transition point and heat deformation temperature, heat aging resistance, tensile strength, bending strength, impact strength, dynamic friction coefficient, limit PV value, Taber abrasion. Such as mechanical properties, especially mechanical strength, sliding properties, heat aging resistance, chemical resistance, boiling water resistance, chemical physical properties such as saturated water absorption, fluidity of melt composition, melt compression moldability, It is characterized by excellent moldability such as melt injection moldability and melt extrusion moldability.
In addition, the method of the present invention is a manufacturing method superior to the conventional method in industrial practice, and is characterized in that the polyamide can be manufactured at a low cost.

[Means for Solving Problems] and [Action] The present invention relates to a low-order condensate [A] formed from an aromatic dicarboxylic acid component unit (a) and an alkylenediamine component unit (b) in a molten state. In the method for producing a polyamide [C], the prepolymer [B] is heated under shearing conditions using a kneading means, and then the prepolymer [B] is heated in a solid state and polycondensed. And (i) the aromatic dicarboxylic acid component unit (a) has a terephthalic acid component unit content of 60 to 100 mol% and an aromatic dicarboxylic acid component unit other than the terephthalic acid component unit content of 0 to 40 mol%. And the alkylenediamine component unit (b) is an aliphatic alkylenediamine component unit having 6 to 18 carbon atoms, (ii) the low-order condensate [A] and the prepolymer [B]
The intrinsic viscosity measured in concentrated sulfuric acid at 30 ° C
_{When A} and [η] _B are satisfied, [η] _A ≦ 0.6 dl / g 0.3 dl / g ≦ [η] _B and [η] _B / [η] _A ≧ 1.1 are satisfied, and the polyamide [C] is When the polyamide is a polyamide insoluble in concentrated sulfuric acid at 50 ° C., a polyamide containing the insoluble polyamide or a polyamide soluble in concentrated sulfuric acid at 50 ° C. and the polyamide [C] is a concentrated sulfuric acid-soluble polyamide, its intrinsic viscosity is the When [η] _C, and the heavy [η] _C ≧ 0.6 dl / g and [η] _C / [η] which satisfies the _B ≧ 1.1, and (iii) a heating temperature in the melt [T _1] The temperature of the condensation reaction mixture is in the melting temperature or below the melting temperature plus 150 ° C, and the heating temperature [T ₂ ] in the solid state is in the range of 150 ° C lower than the melting point of the polycondensation reaction mixture or less than the melting point. And a method for producing a polyamide characterized by: It

In the method of the present invention, a low-order condensate (A) formed from an aromatic dicarboxylic acid component unit (a) and an alkylenediamine component unit (b) used as raw materials for the polycondensation reaction.
Is formed from the aromatic dicarboxylic acid component unit (a) and the alkylene component unit (b) described below. The low-order condensate is obtained by adding an aromatic dicarboxylic acid and an alkylenediamine, a salt thereof or an aromatic dicarboxylic acid ester and an alkylenediamine, if necessary, to a solvent such as water, alcohol, phenols and aromatic hydrocarbons. In the absence and in the absence, usually 120 to 350 ° C, preferably 200 to 300
It is produced by heating to ℃. Among these low-order condensates, a method of using the aromatic dicarboxylic acid and alkylenediamine or a salt thereof is preferable, and particularly, the color tone of the low-order condensate produced when the reaction is performed in an autoclave in the presence of a water solvent. Is preferable, and it is preferable because it has advantages such as easy extraction and easy handling. When the low-order condensate is produced, a catalyst such as phosphoric acid, sodium hypophosphite, octyl phosphate, tristridecyl phosphite, a stabilizer and the like may be added. The intrinsic viscosity [η] of the low-order condensate measured at 30 ° C. in concentrated sulfuric acid must be in the range of 0.6 dl / g or less, preferably 0.01 to 0.
45, particularly preferably in the range of 0.03 to 0.30 dl / g. Its melting point is usually in the range of 200 to 340 ° C. If the low-order condensate [η] exceeds 0.6 dl / g, the production conditions (temperature, time, etc.) of the low-order condensate become severe, and the low-order condensate may be obtained in a color tone or withdrawal. Not only will it become difficult, but the physical properties of the resulting polyamide, such as the color tone and heat aging resistance, will drop significantly.

In the method of the present invention, the aromatic dicarboxylic acid component unit that constitutes the lower-order condensate formed from the aromatic dicarboxylic acid component unit (a) and the alkylenediamine component unit (b) used as raw materials for the polycondensation reaction. (a) is in the range of 60 to 100 mol% of terephthalic acid component units and 0 to 0 of aromatic dicarboxylic acid component units other than terephthalic acid component units.
Aromatic dicarboxylic acid component unit consisting of 40 mol%
A low-order condensate composed of (a) and an aliphatic alkylenediamine component unit (b) having 6 to 18 carbon atoms.

In the polycondensation reaction of the method of the present invention, specific examples of the aromatic dicarboxylic acid component unit (a) constituting the low-order condensate used as a raw material include terephthalic acid, isophthalic acid, phthalic acid and 2-methyl. Each component unit such as terephthalic acid and naphthalene dicarboxylic acid can be exemplified.
The composition of the aromatic dicarboxylic acid component unit (a) may be a terephthalic acid component unit alone, but it is a mixture of a terephthalic acid component unit and the above-exemplified aromatic dicarbanoic acid component unit other than the terephthalic acid component unit. May be. In any case, the composition of the aromatic dicarboxylic acid component unit (a) that constitutes the lower condensate is 60 to 1 terephthalic acid component unit.
It is necessary to consist of a range of 00 mol% and a range of 0 to 40 mol% of aromatic dicarboxylic acid component units other than terephthalic acid component units. Further, the composition of the aromatic dicarboxylic acid component unit (a) is such that when the aliphatic alkylenediamine component unit (b) constituting the low-order condensate is an aliphatic alkylenediamine unit having 6 carbon atoms, the terephthalic acid component unit is When the aromatic dicarboxylic acid component unit other than the terephthalic acid component unit is in the range of 60 to 85 mol% and the content of the aromatic dicarboxylic acid component unit is in the range of 15 to 40 mol%, the polyamide produced by the method of the present invention has high heat resistance such as heat distortion temperature. It is particularly preferable because the properties, mechanical properties such as tensile strength and bending strength, sliding properties and moldability are improved. When the aliphatic alkylenediamine component unit (b) constituting the low-order condensate is an aliphatic alkylenediamine unit having 8 carbon atoms, a terephthalic acid component unit
When it is in the range of 65 to 100 mol% and the aromatic dicarboxylic acid component unit other than the terephthalic acid component unit is in the range of 0 to 35 mol%, the heat resistance characteristics such as heat distortion temperature of the polyamide produced by the method of the present invention. It is particularly preferable because mechanical properties such as tensile strength and bending strength, sliding characteristics, and moldability are improved. When the aliphatic alkylenediamine component unit (b) constituting the low-order condensate is an aliphatic alkylenediamine unit having 10 to 18 carbon atoms, the terephthalic acid component unit is in the range of 75 to 100 mol% and the terephthalic acid component unit. When the aromatic dicarboxylic acid unit other than the above is in the range of 0 to 25 mol%, heat resistance characteristics such as heat distortion temperature of the polyamide produced by the method of the present invention,
Mechanical properties such as tensile strength and bending strength, slidability, and moldability are improved, which is particularly preferable. When the composition of the aromatic dicarboxylic acid component unit (a) is less than 60 mol% of the terephthalic acid component unit and more than 40 mol% of the aromatic dicarboxylic acid component unit other than the terephthalic acid component unit, the heat distortion temperature of the polyamide Heat resistance characteristics such as, mechanical characteristics such as tensile strength and bending strength, chemical characteristics such as sliding characteristics, chemical resistance, and water resistance are deteriorated. Among the aromatic dicarboxylic acid component units other than the terephthalic acid component unit of the aromatic dicarboxylic acid component unit (a) constituting the low-order condensate, an isophthalic acid component unit or a naphthalene dicarboxylic acid component unit is preferable. In particular, an isophthalic acid component unit is preferable. Further, the aromatic dicarboxylic acid component unit (a) constituting the low-order condensate is mainly composed of the terephthalic acid component unit and the aromatic dicarboxylic acid component unit other than the terephthalic acid component unit. In addition to the above essential components, a small amount, for example, about 10 mol% of adipic acid, an aliphatic dicarboxylic acid component unit such as sebacic acid, a tribasic or higher polyvalent carboxylic acid component unit such as trimellitic acid, pyromellitic acid, etc. You can include it.

The aliphatic alkylenediamine component unit (b) constituting the low-order condensate [A] used as a raw material for the polycondensation reaction in the method of the present invention is an aliphatic alkylenediamine having 6 to 18 carbon atoms, 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-dimethyl Butane, 1,2
-Diamino-1-butylethane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane,
1,6-diamino-2,5-dimethylhexane, 1,6-diamino-2,4-dimethylhexane, 1,6-diamino-3,3-dimethylhexane, 1,6-diamino-2,2-dimethyl Hexane, 1,9-diaminononane, 1,6-diamino-2,2,4-trimethylhexane, 1,6-diamino-2,4,4-trimethylhexane, 1,7-diamino-2,3-dimethylheptane , 1,
7-diamino-2,4-dimethylheptane, 1,7-diamino-2,5-dimethylheptane, 1,7-diamino-2,2-dimethylheptane, 1,10-diaminodecane, 1,8-diano-
1,3-dimethyloctane, 1,8-diamino-1,4-dimethyloctane, 1,8-diamino-2,4-dimethyloctane,
1,8-diamino-3,4-dimethyloctane, 1,8-diamino-4,5-dimethyloctane, 1,8-diamino-2,2-dimethyloctane, 1,8-diamino-3,3-dimethyl Octane, 1,8-diamino-4,4-dimethyloctane, 1,6-diamino-2,4-diethylhexane, 1,9-diamino-5-
Examples of each component unit include methylnonane, 1,11-diaminoundecane, and 1,12-diaminododecane. Among these aliphatic alkylenediamine component units (b), 1,6-diaminohexane component units, 1,8-diaminooctane component units, 1,10-diaminodecane component units, 1,12-diaminododecane component units. Alternatively, a mixed component unit thereof is preferable, and a 1,6-diaminohexane component unit is particularly preferable.

In the method of the present invention, the polymerization reaction of the low-order condensate [A] formed from the aromatic dicarboxylic acid component unit (a) and the aliphatic alkylenediamine component unit (b) is first carried out under a shearing condition in a molten state. The pre-polymer [B] is heated by using the following kneading means, and then the pre-polymer [B] is heated in a solid state. As a kneading means under shearing 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, roll, extrusion A machine, a kneader, etc. can be illustrated. Among these methods, there are advantages that the kneading can be easily performed at a high temperature, the prepolymerization can be performed in a short time, and the generated prepolymer can be easily handed. A method using an extruder or a kneader is preferable. As an extruder, one with a vent that can distill off water etc. from the reaction distillate
A single-screw or multi-screw extruder can be used, and by distilling the reaction product from the vent under normal pressure (pressurization) or under reduced pressure, it is possible to easily carry out the reaction under a melting condition for a short time ( Usually, the prepolymer [B] can be produced within 10 minutes or less. [Η] of prepolymer [B] ([η] _B , 3
The value measured in concentrated sulfuric acid at 0 ° C.) must be 0.3 dl / g or more, preferably in the range of 0.4 to 1.4 dl / g, particularly preferably in the range of 0.6 to 1.2 dl / g. Preferably there is. In addition, [η] of the prepolymer [B]
_B and the low Tsugichijimigobutsu [η] ([η] _A) and the ratio of [η] _B
It is necessary that the value of / [η] _A is 1.1 or more, preferably 2.0 or more, particularly preferably 3 to 50. [Η] _B of the prepolymer [B] is
If it is less than 0.3 dl / g or the value of [η] _B / [η] _A is 1.1
When the amount is less than the above, the molecular weight of the obtained polyamide is not sufficient and mechanical properties such as tensile strength and bending strength of the polyamide are deteriorated, or sliding properties are deteriorated, or the polyamide is hard to sufficiently develop strength. It is necessary to considerably increase the molecular weight in the phase polymerization, which requires severe solid-state polymerization conditions, so that the color tone and heat aging resistance of the polyamide are deteriorated.

Further, the heating temperature [T ₁ ] for producing the prepolymer [B] is required to be the melting temperature of the polycondensation reaction mixture or the melting point plus 150 ° C. or higher temperature, preferably the melting temperature. To the melting point plus 100 ° C. or higher. When the heating temperature [T ₁ ] exceeds the melting point of the polycondensation mixture to a temperature higher than 150 ° C., the color tone and heat aging resistance of the prepolymer and polyamide deteriorate.

In the solid-phase polycondensation, the temperature at which the prepolymer [B] is heated in the solid-phase state for polycondensation needs to be 150 ° C. lower than the melting point of the polycondensation reaction mixture or less than the melting point. And preferably from the melting point to 14
0 ° C lower temperature to melting point to 30 ° C lower temperature range, more preferably 120 ° C lower than melting point to 40 ° C lower temperature
It is preferably in the range of a temperature lower by ° C.

The polyamide [C] produced by the method of the present invention is 50
In the case of a polyamide insoluble in concentrated sulfuric acid at 0 ° C, or a polyamide containing the insoluble polyamide or a polyamide soluble in concentrated sulfuric acid at 50 ° C, and the polyamide [C] soluble in concentrated sulfuric acid, Letting [η] _C be the intrinsic viscosity measured in concentrated sulfuric acid, [η] _C is
It is necessary to be 0.6 dl / g or more, preferably 1.0
dl / g or more, particularly preferably 1.3 dl / g or more.
Further, the ratio [η] _C / [η] _B of the [η] _C to the [η] ([η] _B ) of the prepolymer needs to be 1.1 or more, preferably 1.3 or more, particularly preferably Is greater than or equal to 1.5. When the polyamide [C] is a polyamide soluble in concentrated sulfuric acid at 50 ° C., and [η] _C is less than 0.6 dl / g or [η] _C / [η] _B is less than 1.1, the polyamide [C] is Mechanical strength such as tensile strength and bending strength of [C], sliding characteristics, etc. are deteriorated.

When the polyamide [C] is a composition composed of a polyamide insoluble in concentrated sulfuric acid at 50 ° C. and a polyamide soluble in concentrated sulfuric acid at 50 ° C., the proportion thereof is not particularly limited, but the concentrated sulfuric acid-soluble polyamide 100 is preferred. With respect to parts by weight, the concentrated sulfuric acid-insoluble polyamide is in the range of 2 to 1000 parts by weight, particularly preferably 5 to 400 parts by weight.

The polyamide obtained by the method of the present invention has the above-mentioned excellent performance, is used for various molding material applications, and is particularly excellent in performance as a sliding material, a coating agent, an adhesive, It is used for various other purposes. In the polyamide, if necessary, a conventionally known polymer stabilizer,
A plasticizer, a mold release agent, a lubricant, a filler, etc. can be illustrated. As the polymer, nylon 6,6, polyamide such as nylon 6 can be exemplified. The filler is an organic or inorganic compound having various forms such as powder, plate, fiber or cloth, and specifically, silica, alumina, silica-alumina, talc, diatomaceous earth, Clay, kaolin, quartz, glass, mica,
Graphite, molybdenum disulfide, gypsum, red iron oxide, titanium dioxide, zinc oxide, aluminum, copper, stainless steel and other powdery or plate-like inorganic compounds, glass fiber,
Secondary processed products such as carbon fiber, boron fiber, ceramic fiber, asbestos fiber, asbestos fiber, stainless steel fiber and other fibrous inorganic compounds or cloth-like products thereof, polyparaphenylene terephthalamide, polymetaphenylene terephthalamide, Polyparaphenylene isophthalamide, polymetaphenylene isophthalamide, condensate of diaminodiphenyl ether and terephthalic acid (isophthalic acid), wholly aromatic polyamide such as condensate of p (m) -aminobenzoic acid, diamino A wholly aromatic polyamide imide such as a condensation product of diphenyl ether and trimellitic anhydride or pyromellitic anhydride, a wholly aromatic polyimide, a polybenzimidazole, a compound containing a heterocycle such as polyimidazophenanthroline, and polytetrafluoroethylene. Such as powder, plate Can be exemplified a these secondary processed products, such as fibrous or cloth-like material, it may be used by mixing two or more of these. As these fillers, those treated with a silane cutter or a titanium cutter can be used as well.

Among the above-mentioned fillers, silica, silica-alumina, alumina, titanium dioxide, graphite, molybdenum disulfide, polytetrafluoroethylene is preferably used as the powdery filler, and particularly graphite, molybdenum disulfide or polytetrafluoroethylene is used. The use of tetrafluoroethylene is preferable because the molded product obtained from the composition has improved wear resistance such as dynamic friction coefficient, Taber wear and critical PV value. It is preferable that the average particle size of such a filler is usually in the range of 0.1 mμ to 200 μ, and particularly in the range of 1 mμ to 100 μ because the above-mentioned abrasion resistance is remarkably improved. The proportion of the filler to be blended is usually in the range of more than 0 to 200 parts by weight, preferably more than 0 to 100 parts by weight, particularly preferably 0.5 to 50 parts by weight, relative to 100 parts by weight of the polyamide. The range is parts by weight.

Further, among the above-mentioned fillers, examples of organic fibrous fillers include polyparaphenylene terephthalamide fibers, polymetaphenylene terephthalamide fibers, polyparaphenylene isophthalamide fibers, polymetaphenylene isophthalamide fibers, and diamino. When a wholly aromatic polyamide fiber such as a fiber obtained from a condensate of diphenyl ether and terephthalic acid or isophthalic acid is used, the molded product obtained from the composition has mechanical properties such as tensile strength and Izod impact strength, and heat resistance. This is preferable because heat resistance characteristics such as deformation temperature are improved. Further, when glass fiber, carbon fiber or boron fiber is used as the inorganic fibrous filler among the above-mentioned fillers, the molded article obtained from the composition has a mechanical strength such as tensile strength, bending strength and bending elastic modulus. Properties, heat resistance properties such as heat distortion temperature, and chemical and physical properties such as water resistance are improved, which is preferable. When the average length of the organic or inorganic fibrous filler is usually in the range of 0.1 to 20 mm, particularly 1 to 10 mm, the moldability of the composition is improved and the molded product obtained from the composition is obtained. It is preferable because heat resistance characteristics such as heat deformation temperature and mechanical characteristics such as tensile strength and bending strength are improved. The mixing ratio of the organic or inorganic fibrous filler is usually more than 0 and 200 parts by weight, preferably 5 to 180 parts by weight, based on 100 parts by weight of the polyamide. It is particularly preferably in the range of 5 to 150 parts by weight.

The polyamide produced by the method of the present 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 described with reference to examples. The method for preparing the test piece and the method for evaluating each performance are shown below.

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

TA: terephthalic acid IA: isophthalic acid C ₆ DA: 1,6-diaminohexane (method for preparing test pieces and evaluation of physical properties) Polyamide was crushed by a crusher (32 mesh passes), and the conditions were 100 ° C and 1 mmHg. After drying for 12 hr, the polyamide was pressed with a press molding machine in a nitrogen atmosphere at 100 kg / cm ²
After hot pressing at a temperature 20 ° C. higher than the melting point of the concentrated sulfuric acid-soluble polyamide under the pressure of 1., and then cold pressing at a temperature of 20 ° C., a compression molded plate having a thickness of 2 mm to 10 mm was produced. These molded plates were cut into the size of each test piece shown in Table 1 and then left in an atmosphere having a temperature of 23 ° C. and a relative humidity of 65% for 96 hours and then subjected to a test.

In addition, the glass fiber compound is a specified amount of crushed and dried polyamide and a specified amount of glass fiber (average length 6 mm, Nitto Boseki KK
The manufactured manufactured strand (CS6PE-231) was supplied to a uniaxial extruder (L / D = 28, 20 mmφ) and mixed to obtain a strand of 8 to 10 mm. The test piece was prepared in the same manner as when the glass fiber was not added.

Example 1 123.6 g (0.744M) of terephthalic acid, 52.9 g of isophthalic acid
(0.318M). Hexamethylenediamine 123.4g (1.062M)
Then, 74 g of ion-exchanged water was charged into one autoclave, and after sufficiently replacing with N ₂ , 250 g was taken for 2 hours with stirring.
The temperature was raised to ° C. Further, the reaction was allowed to proceed at 250 ° C. for 1 hour in a dense state, stirring was stopped, and the reaction mixture was taken out from the bottom of the autoclave at a differential pressure of 10 kg / cm ² . N ₂ Medium 100
A low-order condensate was obtained by drying overnight at 100 ° C and 100 mmHg. The [η] of this low-order condensate (in conc H ₂ SO ₄ at 30 ° C.) is 0.1 dl / g
It was. This low-order condensate is a twin-screw extruder (screw diameter
30mm, L / D = 42, barrel temperature (℃) 30/260/280/30
0/300/320/320/340/340/340, 4th and 6th zones are vent to atmosphere, 8th zone is 90mmHg decompression, rotation speed
80 rpm, oligomer feed rate 2 kg / hr, N ₂ purge for exhaust, proceeded polycondensation under melting (the temperature of melt polymerization in the extruder was always below 90 ° C. higher than the melting point of the polycondensation reaction mixture). Hold) [η] is 0.70dl / g (conc H ₂ HO ₄ , 30
C.) and a melting point of 320.degree. This prepolymer was subjected to solid phase polymerization under stirring at 250 ° C. and 1 mmHg for 3 hours to give [η] of 1.40 dl / g (conc H ₂ SO ₄ , 30
A polyamide having a melting point of 330 ° C. was obtained. The temperature during solid state polymerization was always kept at a temperature 80 ° C to 70 ° C lower than the melting point of the polycondensation reaction product. Table 2 shows the physical properties of this polyamide.
It was shown to.

Example 2 74 g of ion-exchanged water was used in the synthesis of the low-order condensate in Example 1.
A polyamide was synthesized by the method described in Example 1 except that 128 g was used instead. The results are shown in Table 2.

Example 3 A polyamide was prepared by the method described in Example 2 except that 26 g of ion-exchanged water was used at 280 ° C. instead of using 74 g of ion-exchanged water at 250 ° C. in Example 1. Synthesized. The results are shown in Table 2.

Example 4 In Example 1, the pressure reduction degree of the 8th zone when producing a prepolymer from a low-order condensate using a twin-screw extruder was 90 mm.
A polyamide was synthesized by the method described in Example 1 except that 1 mmHg was used instead of Hg. The results are shown in Table 2.

Example 5 In Example 4, the amounts of terephthalic acid and isophthalic acid used were changed to 132.3 g (0.797 M) and 44.1 g (0.266 M), respectively, to synthesize a low-order condensate and to synthesize a prepolymer. The barrel temperature (℃) of the twin-screw extruder is 30/270/280 /
A polyamide was synthesized by the method described in Example 4 except that a prepolymer was synthesized instead of 300/300/320/350/360/350/350. 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 in Example 4 were changed to 280 ° C. and 8 hours, respectively. The results are shown in Table 2.

Example 7 Example 3 was repeated except that 300 g of a nylon salt of terephthalic acid and decamethylenediamine and 128 g of ion-exchanged water were used instead of using terephthalic acid, isophthalic acid and hexamethylenediamine 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 8 100 parts by weight of polyamide described in Example 1 and glass fiber 66
A glass fiber blend was prepared from the parts by weight and the physical properties were evaluated. The results are shown in Table 2.

Comparative Example 1 A polyamide was synthesized by the method described in Example 1 except that the amounts of terephthalic acid and isophthalic acid used in Example 1 were changed to 109.4 g and 67.1 g, respectively, to synthesize a low-order condensate. The results are shown in Table 2.

Comparative Example 2 In Example 4, the physical properties of this prepolymer were examined without using solid-state polymerization of the prepolymer as a polyamide. The results are shown in Table 2.

Comparative Example 3 In Example 1, a polyamide was synthesized by the method of Example 1 except that the production conditions for producing the low-order condensate were as follows. That is, the reaction temperature was raised to 250 ° C. over 2 hours and then reacted for 1 hour. After that, the temperature was raised to 280 ° C, and the pressure was gradually released to maintain the internal temperature at this temperature over 1 hour.
When it reached 15 kg / cm ² , the temperature was raised to 330 ° C and returned to atmospheric pressure. Furthermore, the temperature was raised to 350 ° C. and the low-order condensate was extracted under the pressure of N ₂ . This low-order condensate has a barrel temperature (° C) of a twin-screw extruder of 30/270/300/330/330/330/350/350/340
The result of synthesizing the polyamide by the method described in Example 1 is shown in Table 2 except that the vent of the 8th zone was opened to the atmosphere and the prepolymer was synthesized.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-59-161428 (JP, A) JP-A-59-155426 (JP, A) JP-A-60-163927 (JP, A) JP-A-60- 163928 (JP, A)

Claims (1)

[Claims] 1. A low-order condensate [A] formed from an aromatic dicarboxylic acid component unit (a) and an alkylenediamine component unit (b) is heated in a molten state under shearing conditions using a kneading means. A method for producing a polyamide [C] by preparing a prepolymer [B] and then heating the prepolymer [B] in a solid state to cause polycondensation, which comprises (i) the aromatic dicarboxylic acid component unit: (a) comprises 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 alkylenediamine component units (b) are carbon. An aliphatic alkylenediamine component unit of the formula 6 to 18, (ii) the low-order condensate [A] and the prepolymer [B]
The intrinsic viscosity measured in concentrated sulfuric acid at 30 ° C
_{When A} and [η] _B are satisfied, [η] _A ≦ 0.6 dl / g 0.3 dl / g ≦ [η] _B and [η] _B / [η] _A ≧ 1.1 are satisfied, and the polyamide [C] is When the polyamide is a polyamide insoluble in concentrated sulfuric acid at 50 ° C., a polyamide containing the insoluble polyamide or a polyamide soluble in concentrated sulfuric acid at 50 ° C. and the polyamide [C] is a concentrated sulfuric acid-soluble polyamide, its intrinsic viscosity is the When [η] _C, and the heavy [η] _C ≧ 0.6 dl / g and [η] _C / [η] which satisfies the _B ≧ 1.1, and (iii) a heating temperature in the melt [T _1] The melting temperature of the condensation reaction mixture to the melting point plus 150 ° C or less, and the heating temperature in the solid state [T ₂ ] is 150 ° C lower than the melting point of the polycondensation reaction mixture or less than the melting point. A method for producing a polyamide, comprising: