JP3395389B2 - Method for producing polyamide - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyamide, and more particularly to a method for producing a heat-resistant polyamide suitable for automobile parts and electric / electronic parts.

[0002]

2. Description of the Related Art Polyamides are widely used in the fields of automobiles, electric and electronic fields, etc. by utilizing their excellent properties as engineering plastics.

Conventionally, nylon 6 and nylon 66 reinforced with glass fibers have been used for these molded products (Japanese Patent Laid-Open No. 59-161461), but the temperature of the engine room of an automobile due to recent technological innovation has been improved. With the rise in temperature and the progress of microelectronics, there has been a demand for materials for ultra-thin molded products that can withstand use in higher temperature atmospheres. However, the melting points (Tm) of nylon 6 and nylon 66 are 220 ° C. and 260 ° C., respectively, and even if they are reinforced with glass fiber, the limits of the heat distortion temperature are up to their respective melting points.

Recently, many polyamide resin compositions containing terephthalic acid and isophthalic acid, and glass fiber reinforced products thereof have been proposed as polyamide resin compositions capable of withstanding use under these high-temperature atmospheres (Japanese Patent Laid-Open No. Sho 5).
9-161428, JP-A-59-155426, JP-A-59-53536, JP-A-62-1.
56130).

As a method for polymerizing these polyamides,
Usually, melt polymerization is used, but since the obtained polyamide has a high melting point, a high temperature is required for the polymerization, and as a result, the obtained polyamide is thermally deteriorated, the color tone is changed, and the mechanical strength is lowered. It was easy to cause problems such as.

For this purpose, after forming the primary condensate,
A method for increasing the degree of polymerization has been proposed. For example, a 40 to 70% by weight aqueous solution of the raw material is passed through a heated coil pipe by a piston flow to obtain a primary condensate (JP-A-60-206827), and the raw material concentration is about 5
A method has been proposed in which a 0% by weight aqueous solution is continuously polymerized with a primary condensate through a tubular evaporator (JP-A-2-41318). In these methods, an attempt is made to improve the heating time by using the movement of the reaction system as a piston flow. Due to the viscosity of the molten primary condensate, the flow of material in the vicinity of the tube wall of the reaction is significantly slowed and stagnates,
As a result, the polymer quality tends to deteriorate during long-term operation.
Further, there is a problem that it is difficult to switch the product type as compared with batch polymerization.

Therefore, attempts have been made to solve these problems and obtain a high-quality polymer by using a batch polymerization apparatus for the synthesis of the primary condensate. For example, 220-2
After the primary condensate is polymerized at 80 ° C., the reaction mixture is extracted with a pressure difference of 10 kg / cm ² , and then the polymerization degree is increased by an extruder (JP-A-3-43417), prepolymerization at a temperature below the melting point of the polymer, Then, a method of solid phase polymerization
170895).

[0008]

However, in these polymerization methods, the color tone, tensile strength, tensile elongation, chemical resistance, etc. are insufficient, and improvements have been desired. Therefore, in the present invention, by carrying out semi-continuous batch polymerization using a large number of containers from the raw material charging to the completion of the primary condensate polymerization step, only the minimum required heat is required, and high productivity and high productivity are achieved. It is intended to provide a manufacturing method for obtaining a quality polyamide.

[0009]

Therefore, in view of the above situation, the inventors of the present invention have made diligent studies on a method for solving the above-mentioned problems, and as a result, have found that a container is provided between the charging of raw materials and the completion of the primary condensate polymerization step. By carrying out semi-continuous batch polymerization using a large number of units, the inventors have invented a production method for obtaining a high-quality polyamide with a minimum required heat. .

That is, according to the present invention, "in the method for producing a polyamide containing a terephthalic acid structure, the relative viscosity (ηr) of a 1% sulfuric acid solution at 25 ° C is 1. After obtaining a primary condensate of 04 to 2.5, the degree of polymerization is further increased.

The details of the present invention will be described below.

The polyamide of the present invention is a polyamide containing a component consisting of terephthalic acid. The melting point of the polyamide of the present invention is preferably 230 to 340.
C., more preferably 270 to 340.degree. 230
When the melting point is lower than 0 ° C, it is difficult to obtain the heat resistant resin which is the object of the present invention, and when the melting point is higher than 340 ° C, the processing temperature of the resin becomes high, and problems such as foaming due to thermal decomposition reaction tend to occur.

Although diamines are used to obtain polyamides from terephthalic acid, aliphatic diamines are preferably used. As the aliphatic diamine, any one may be used, but when the aliphatic diamine having a small number of carbon atoms is used, the melting point of the polyamide is increased, and when the aliphatic diamine having a large number of carbon atoms is used, the water absorption is lowered, and therefore the balance is lowered. Aliphatic diamines having 4 to 14 carbon atoms are preferable. Specific examples thereof include 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,5-diamino-2-methylpentane, 1,7-diaminoheptane, 1,8-diamino. With aliphatic alkylenediamines such as octane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,13-diaminotridecane, 1,14-diaminotetradecane. is there. Among them, diamines having 6 or 12 carbon atoms and diamines having 6 carbon atoms are preferable, and 1,6-diaminohexane is exemplified as a representative one. .

These diamines may be used alone or in combination of two or more. In addition, aromatic diamines such as metaxylylenediamine, paraxylylenediamine, and phenylenediamine can also be used within a range that does not impair the object of the present invention.

As the dicarboxylic acid component, it is necessary to contain terephthalic acid. Further, a dicarboxylic acid component other than terephthalic acid can be blended, and examples of such a dicarboxylic acid component include oxalic acid, malonic acid, succinic acid,
Aliphatic with 2 to 18 carbon atoms such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, prasiric acid, tetradecanedioic acid, pentadecanedioic acid and octadecanedioic acid. It is preferable to use aromatic dicarboxylic acids such as dicarboxylic acid and isophthalic acid. Particularly preferred are adipic acid and isophthalic acid.

Further, within a range not impairing the object of the present invention,
Polyamide raw materials other than those mentioned above may be used in combination. For example, lactams such as ε-caprolactam, ζ-enanthlactam, η-capryllactam, and ω-laurolactam, and aminocarboxylic acids that give a polyamide structure similar to the above-mentioned lactams. Among the lactams,
ε-caprolactam is preferably used.

When an aliphatic diamine component having 6 carbon atoms is used, the structural unit (I)

[Chemical 5] (Hexamethylene terephthalamide unit (hereinafter referred to as 6T)), and at least one structural unit selected from structural units (II) to (IV),

[Chemical 6] (Hexamethylene isophthalamide unit (hereinafter referred to as 6I)),

[Chemical 7] (Hexamethylene adipamide unit (hereinafter referred to as 66)),

[Chemical 8] A 6T-containing copolyamide having a repeating unit consisting of (caproamide unit (hereinafter referred to as 6)) is preferably used.

With respect to the copolymerization ratio in the above 6T-containing copolyamide, for example, in the case of 2 components, in the case of 6T / 6I, the copolymerization ratio is 45 / 55-80 / 20, preferably 5 by weight.
5 / 45-80 / 20, more preferably 60 / 40-7
Used in the range of 5/25. Further, at 6T / 66, the copolymerization ratio is 20/80 to 80/20 in weight ratio, preferably 30/70 to 70/30, and more preferably 30/70.
Used in the range of ~ 60/40. Further, in 6T / 6, the copolymerization ratio is 40/60 to 90/10 by weight, preferably 55/45 to 85/15, and more preferably 60/4.
It is used in the range of 0 to 80/20. The copolymerization ratio of these 6T-containing copolyamides is such that the polymer melting point is about 23.
It relates to a polyamide in the range of 0 ° C to 340 ° C. The copolymerization ratios by weight of 6T / 6I, 6T / 66 and 6T / 6 are 45/55, 20/80 and 4, respectively.
When the amount of 6T is smaller than 0/60, problems tend to occur in terms of heat resistance and water absorption. The copolymerization ratios of 6T / 6I, 6T / 66 and 6T / 6 are 80/20 and 80, respectively.
When the amount of 6T is larger than / 20 and 90/10, the polymer melting point is increased and the heat resistance is improved, but the processing temperature is increased and the polymer is apt to cause thermal decomposition.

Polyamides having 3 or more components containing 6T units are also preferably used. For example, those copolymerized with tetramethylene adipamide unit, hexamethylene sebacamide unit, hexamethylene dodecamide unit, lauroamide unit, paraxylylene adipamide unit, metaxylylene adipamide unit and the like are preferably used. To be

When an aliphatic diamine having 12 carbon atoms is used, a homopolymer of terephthalic acid (hereinafter referred to as 12T) is used.
Or a repeating unit such as a hexamethylene adipamide unit, a dodecamethylene adipamide unit, a hexamethylene isophthalamide unit, a dodecamethylene isophthalamide unit, a dodecamethylene isophthalamide unit, and a caproamide unit. 12T-containing polyamide is preferably used.

The method of the synthesis, wherein the primary condensation product is of the present invention then, during the period from the material feed to the primary condensation product polymerization completed
It is semi-continuously synthesized via a batch type container of three or more tanks . By producing the primary condensate stepwise in three or more tanks , not only efficient polymerization can be achieved, but also the heating / cooling cycle of each tank is shortened so that an excessive heat history is not applied. Further, by semi-continuously polymerizing,
Liquid level fluctuations are reduced and unnecessary heat is not applied to the residual portion of the gas phase portion, so that a polyamide with extremely little thermal deterioration can be obtained.

[0022] For example, when performing Polymerization in 3 bath, the container for the first tank to Shiocho step, the second bath the concentration step for containers,
The third tank is how the polymerization vessel. In addition, depending on the case, there may be a salt storage container for storing the prepared salt, a container for storing the concentrate, and the like. Further, the polymerization may be performed twice or more. Although any tank may be used for salt preparation, concentration, and synthesis of the primary condensate, a tank under normal pressure or under pressure is preferably used. If only salt adjustment is performed, a normal pressure container is preferably used.

The raw material is not particularly limited to be charged, but water is usually added as a solvent, and the concentration of the raw material is generally 5 to 90% by weight, and 15 to 85% by weight shortens the polymerization time. Is also preferable.

The salt tone is a step of mixing a dicarboxylic acid as a polymerization raw material and a diamine to produce a dicarboxylic acid / diamine salt. By producing a salt, the polymerization reaction proceeds rapidly. The salt to be prepared is a combination of the above-mentioned dicarboxylic acids such as terephthalic acid and a diamine, and examples thereof include adipic acid / hexamethylenediamine salt (AH salt) obtained from adipic acid and hexamethylenediamine, and terephthalic acid and hexamethylene diamine. There is terephthalic acid / hexamethylenediamine salt (6T salt) obtained from methylenediamine.

During the salt preparation, the pH is finely adjusted with a dicarboxylic acid and a diamine, and the pH during the salt preparation is a salt neutralization point ± 0.5.
Is preferable, and particularly preferably, the neutralization point of the salt ± 0.
It is within the range of 2. As for the salt condition, the mixture of raw materials is 0
℃ or more, preferably 50 ℃ or more, more preferably 80 ℃
It is preferable to raise the temperature to 100 ° C. or more and 160 ° C. or less, preferably 150 ° C. or less, more preferably 130 ° C. or less, and stir to obtain an aqueous salt solution. The salt adjustment pressure is adjusted so as to control the temperature during salt adjustment and is not less than atmospheric pressure and not more than 4 kg / cm ² -G, preferably 3 kg / cm.
Below ^2- G. Usually, an aqueous salt solution prepared from a raw material is used, but when a salt is available as a raw material, it can be used as it is.

The concentration step is a step of removing the solvent of the reaction solution from the reaction system at a low temperature at which the polymerization hardly progresses. By concentrating, the polymerization time is shortened, the thermal history at high temperature is suppressed, and high quality polyamide is obtained.
In the concentration step, the concentration of the solution is preferably 60% or more for efficient polymerization. The concentration of the raw material charged is more preferable (if the salt preparation step is involved, the value of the concentration after the salt preparation step) +2 to + 75% by weight, particularly preferably +5 to + 65% by weight. Concentration time is within 5 hours for the obtained polyad. The concentration step is performed in the range of 90 to 220 ° C., and further 100 to
210 degreeC is preferable and 130-200 degreeC is especially preferable. The pressure in the concentration step is usually 0 to 20 kg / cm ² -G, preferably 1 to 10 kg / cm ² -G. Also, to promote concentration,
For example, the forced discharge operation can be performed by a nitrogen stream or the like. When a phosphorus-based catalyst is added during the concentration step, it is microdispersed, so that the reaction rate increases when the degree of polymerization is increased. In order to promote microdispersion, for example, stirring,
It is also possible to use operations such as bubbling together. When the raw materials are two or more kinds of dicarboxylic acids or diamines, for example, when preparing AH salt and 6T salt,
The salt of the raw material and the concentration of the raw material may be prepared separately or simultaneously, but it is preferable that they are finally mixed by the time the polymerization of the primary condensate is completed. .

The polymerization step is usually carried out by heating under stirring conditions. The reaction temperature is usually 150 ° C
~ 350 ° C is used, preferably 180 ° C to 340
C., more preferably 190 to 330.degree. When the reaction temperature is lower than 150 ° C, the reaction time becomes long, which is not preferable. Further, if the reaction temperature is higher than 350 ° C, foaming occurs due to thermal decomposition of the polyamide, which is not preferable. Further, it is carried out at a temperature higher than the temperature of the step before the polymerization step. The pressure during the reaction is from the pressure before the polymerization step to 150 kg.
/ cm ² -G, preferably the pressure before the primary condensate polymerization step ~ 7
0kg / cm ² -G, and more preferably is operated so as to keep the range of the primary condensation product polymerization step prior to the pressure ~60kg / cm ² -G.

A phosphorus-based catalyst may be used in the production of the polyamide of the present invention. Phosphorus-based catalysts have a catalytic function of polymerization reaction, for example, hypophosphite, phosphate, hypophosphorous acid, phosphoric acid, phosphoric acid ester, polymetaphosphoric acids, polyphosphoric acids, phosphine oxides, Phosphonium halogen compounds and the like are preferable, and hypophosphite, phosphate, hypophosphorous acid, and phosphoric acid are particularly preferable. As the hypophosphite, for example, sodium hypophosphite, potassium hypophosphite, calcium hypophosphite,
Magnesium hypophosphite, aluminum hypophosphite, vanadium hypophosphite, manganese hypophosphite, zinc hypophosphite, lead hypophosphite, nickel hypophosphite, cobalt hypophosphite, hypophosphite Ammonium phosphate and the like are preferable, and sodium hypophosphite, potassium hypophosphite, calcium hypophosphite, and magnesium hypophosphite are particularly preferable. As the phosphate, for example, sodium phosphate, potassium phosphate, potassium dihydrogen phosphate, calcium phosphate, vanadium phosphate, magnesium phosphate, manganese phosphate, lead phosphate, nickel phosphate, cobalt phosphate, phosphate Ammonium, diammonium hydrogen phosphate and the like are preferable. Examples of the phosphoric acid ester include ethyl octadecyl phosphate. Examples of polymetaphosphoric acids include sodium trimetaphosphate,
Examples include sodium pentametaphosphate, sodium hexametaphosphate, polymetaphosphoric acid, and the like. Examples of polyphosphoric acids include sodium tetrapolyphosphate and the like. Examples of the phosphine oxides include hexamethylphosphoramide.

The amount of the phosphorus-based catalyst added is preferably 0.0001 to 5 parts by weight, more preferably 0.001 to 1 part by weight, based on 100 parts by weight of the polyamide. Further, the addition time may be any time as long as the degree of polymerization is completed, but it is preferably from the time of charging the raw materials to the completion of the primary condensate polymerization step. In addition, for example, the raw materials may be added, the concentration step may be completed, the polymerization degree may be increased, or the like may be added in multiple times.

25% of a 1% sulfuric acid solution of the obtained primary condensate
The relative viscosity at 0 ° C. is required to be 1.04 to 2.5, preferably 1.08 to 2.3, and particularly preferably 1.08 to 2.1. When the relative viscosity is less than 1.04, the polymerization time for increasing the degree of polymerization becomes long, and
If the relative viscosity exceeds 2.5, the melt viscosity of the primary condensate becomes too high, and ejection failure may occur, which is not preferable. The water content of the primary condensate is preferably 0% by weight.
As described above, the content is 20% by weight or less, more preferably 10% by weight or less, and particularly preferably 5% by weight or less. When it exceeds 20% by weight, the polymerization time becomes long and foaming occurs when the degree of polymerization is increased.

Next, as a method for increasing the degree of polymerization of the primary condensate, there are a method using a melter, a method of solid phase polymerization, a method of using a melter and a solid phase polymerization machine together. When using a melting machine, the melting temperature is 10 to 7 higher than the melting point of the primary condensate.
A range of 0 ° C. higher is preferable. In order to prevent thermal decomposition and thermal deterioration of the polymer, the upper limit temperature is usually set to 370 ° C or lower. As the melting machine, an extruder, a kneader or the like can be used, but a twin-screw extruder or a twin-screw kneader is preferable. The residence time in the melting machine is not particularly limited, but it is preferably 20 seconds or longer, particularly preferably 30 seconds or longer. If the residence time is short, the degree of polymerization cannot be effectively increased, which is not preferable. It is also effective to connect two or more melting machines in series in order to increase the residence time and increase the degree of polymerization. If necessary, the polymer having a high degree of polymerization can be solid-phase polymerized to further increase the degree of polymerization.

On the other hand, as a method of solid-phase polymerization of the primary condensate, a method of polymerization under pressure or normal pressure in the presence of an inert gas, a method of polymerization under reduced pressure, or a combination thereof may be used. . Solid-state polymerization temperature is 15
It is necessary to be 0 ° C. to (melting point of primary condensate) or less, and preferably 200 ° C. to (melting point of primary condensate −10).
C.), more preferably 220.degree. C. to (melting point of primary condensate-15.degree. C.). If the solid phase polymerization temperature is lower than 150 ° C., the reaction rate becomes slow, which is not preferable. The solid-phase polymerization time can be selected arbitrarily until the relative viscosity of the polyamide used in ordinary molded articles is reached. The solid-state polymerization apparatus of the present invention is not particularly limited, and any known method can be used. Specific examples of the solid-state polymerization apparatus include kneader, twin-screw paddle type, tower type, rotating drum type and double-cone type solid-state polymerization apparatus, etc. There is no particular limitation on the degree of polymerization of the polyamide obtained in the present invention. ,
Usually, a 1% sulfuric acid solution having a relative viscosity (ηr) at 25 ° C. of 1.8 to 8.0 can be arbitrarily used.

In ordinary polyamide polymerization, it is common to charge the raw materials so that the total amount of carboxyl groups and the total amount of amino groups contained in the monomer and the dicarboxylic acid / diamine salt are equal. It is also possible to prepare a polyamide having a large amount of terminal carboxyl groups or terminal amino groups by adding an excess of dicarboxylic acid component or diamine component when charging the raw materials. The amount of the excess dicarboxylic acid or diamine added is 0 mol% or more, preferably 0.1%.
3 mol% or more, particularly preferably 0.5 mol% or more, 10
A range of not more than mol%, preferably not more than 8 mol%, particularly preferably not more than 7 mol% is used. Addition amount is 10 mol%
If it exceeds, it becomes difficult to increase the degree of polymerization, which is not preferable.
Further, in the production method of the present invention, it is effective to add a polymerization degree modifier in order to facilitate the adjustment of the polymerization degree of the polyamide and the adjustment of the polymerization degree when the polymerization degree is increased. As the polymerization degree control agent,
Usually, a monoamine compound and a monocarboxylic acid compound are used, but acetic acid, benzoic acid and stearic acid are preferable, and acetic acid and benzoic acid are particularly preferable. The degree of polymerization modifier is 0 times or more, preferably 0.0001 times or more, and 0.1 times the moles of the constituent monomers and the total moles of the dicarboxylic acid component unit and the diamine component unit of the salt. It is used in an amount of not more than mol, preferably not more than 0.05 times mol.

A filler may be further added to the polyamide obtained in the present invention. As the filler, glass fiber or beads, talc, kaolin, wollastonite, mica, silica, alumina, diatomaceous earth, clay, gypsum, red iron oxide, graphite, titanium dioxide, zinc oxide, copper, stainless powder, etc. Examples of the compound are plate-shaped or plate-shaped inorganic compounds and other polymer fibers (carbon fibers, aramid fibers), and glass fibers are preferable.
Particularly preferred glass fibers are glass rovings, glass chopped strands, glass yarns and the like made from strands of continuous long fibers having a diameter of about 3 to 20 μm. The blending ratio of such a filler is usually the polyamide 10
0 part by weight or more, preferably 1 part by weight or more, particularly preferably 10 parts by weight or more, 200 parts by weight or less, preferably 150 parts by weight or less, particularly preferably 10 parts by weight.
It is in the range of 0 parts by weight or less. Filler content is 200
If it exceeds the weight part, not only the fluidity at the time of melting becomes poor, it becomes difficult to injection-mold a thin molded product, but also the appearance of the molded product deteriorates, which is not preferable. There is no particular limitation on the method of adding a filler to the polyamide of the present invention,
Any known method can be used. Specific examples of the compounding method include a method in which a filler is dry blended with polyamide pellets, and the resulting mixture is melt-kneaded with a single-screw or twin-screw extruder. Further, when the polymerization degree is increased by an extruder, a method of adding a filler from the middle of the extruder is preferable because of high production efficiency.

In the present invention, a catalyst, a heat resistance stabilizer, a weather resistance stabilizer, a plasticizer, a mold release agent, a lubricant, a crystal nucleating agent, etc. may be used in the melt polymerization, the high polymerization degree of extrusion, the compound or the molding step, etc. Pigments, dyes, other polymers and the like can be added. These additives include heat-resistant stabilizers (hindered phenol-based, hydroquinone-based, phosphite-based and substitution products thereof, copper iodide, potassium iodide, etc.), weather-resistant stabilizers (resorcinol-based, salicylate-based, benzoic acid-based Triazole-based, benzophenone-based, hindered amine-based), release agents and lubricants (montanic acid and its salts, its esters, its half esters,
Stearyl alcohol, stearamide, various bisamides, bisurea and polyethylene wax), pigments (cadmium sulfide, phthalocyanine, carbon black, etc.), and dyes (nigrosine, etc.), other polymers (other polyamides, polyesters, polycarbonates, etc.)
Polyphenylene ether, polyphenylene sulfide,
Liquid crystal polymer, polyether sulfone, ABS resin,
SAN resin, polystyrene, acrylic resin, polyethylene, polypropylene, ethylene / α-olefin copolymer, ionomer resin, SBS, SEBS and the like).

From the viewpoint of productivity, it is more preferable that the compounding of the additives is carried out simultaneously with the polymerization degree in the extruder or continuously.

The polyamide of the present invention and the composition obtained therefrom can be used for switches, micro slide switches, D
IP switches, switch housings, lamp sockets, binding bands, connectors, connector housings, connector shells, IC sockets, coil bobbins, bobbin covers, relays, relay boxes, capacitor cases, motor internal parts, small motor cases, gear·
Cams, dancing pulleys, spacers, insulators, fasteners, buckles, wire clips, bicycle wheels, casters, helmets, terminal blocks, power tool housings, starter insulating parts, spoilers, canisters, radiator tanks, chamber tanks, reservoir tanks, Fuse box, air cleaner case, air conditioner fan, terminal housing, wheel cover, intake / exhaust pipe, bearing retainer, cylinder head cover, intake manifold, water pipe impeller, engine roll damper, clutch release, speaker diaphragm, heat resistant container,
Microwave oven parts, rice cooker parts, printer ribbon guides, double-sided adhesive tape between IC chips, electric / electronic-related parts such as IC and lead double-sided adhesive tape, automobile / vehicle-related parts, household / office electric appliance parts It is effective for computer related parts, facsimile / copier related parts, machine related parts, and other various applications.

[0038]

The present invention will be described in more detail with reference to the following examples. The properties in the examples and comparative examples were measured by the following methods. 1) Melting point (Tm) Using DSC (PERKIN-ELMER7 type), samples 8 to 10
Let (T) be the temperature at which the maximum value of the melting curve obtained by measuring mg at a heating rate of 20 ° C./min. Sample 8-
10 mg is heated at a temperature rising rate of 20 ° C / min to T + 20 ° C.
For 5 minutes, and then at a temperature decrease rate of 20 ° C / min for 30 minutes.
After cooling to ℃, holding at 30 ℃ for 5 minutes, then again at 20 ℃
Heat to T + 20 ° C. at a heating rate of / min. The maximum value of the melting curve at this time was defined as the melting point (Tm). 2) Relative Viscosity (ηr) According to JIS K6810, 1 g of a sample was dissolved in 100 ml of 98% concentrated sulfuric acid and the relative viscosity at 25 ° C. was measured. 3) Tensile Strength and Tensile Elongation Measured according to ASTM D638. 4) Chemical resistance (LLC resistance) ASTM No. 1 dumbbell is 50% by weight of LLC (Toyota genuine long life coolant, manufactured by Toyota Motor Corporation)
After being immersed in an aqueous solution and treated in an autoclave at 130 ° C. for 500 hours, the tensile strength was measured according to ASTM D638.

Each embodiment will be described below. Table 1 shows the conditions for polymerization and increasing the degree of polymerization. The addition amount of the monocarboxylic acid in this means the amount (double mole) with respect to the number of moles of the monomer of the constituent component or the total number of moles of the dicarboxylic acid component unit and the diamine component unit of the salt.

Example 1 <3 tanks. Uses containers for salt preparation process and concentration process. > Terephthalic acid, adipic acid, hexamethylenediamine,
Acetic acid and ion-exchanged water are used as the raw material composition ratio and the concentration of 60% in Table
Then, a total of 30 kg was charged into the container for the salt preparation step, and after sufficiently purging with nitrogen, salt was prepared under stirring at 110 ° C. and 0.5 kg / cm ² -G.

Next, the prepared solution of salt, acetic acid and ion-exchanged water was transferred to a pre-heated container for a batch type concentration step, the content was heated to 130 ° C., and the pressure was adjusted to 3.0. It was concentrated to a concentration of 80% by weight over 2.0 hours under the condition of kg / cm ² -G.

Further, this solution was transferred to a preheated batch polymerization tank, and after adding sodium hypophosphite, the temperature was raised to 270 ° C. over 3.5 hours with stirring, and the polymerization pressure was adjusted to 17 It was set to kg / cm ² -G. 270 for another 30 minutes
Maintained at 275 ° C to complete the reaction. The discharge was performed by supplying ion-exchanged water with a metering pump at a rate of 3 l / hr and keeping the water vapor pressure at 17 kg / cm ² -G for 1 hour.

The obtained primary condensate was vacuum dried at 100 ° C. for 24 hours, and then melted to a high degree of polymerization by melting in a 30 mmφ bent type twin-screw extruder at a residence time of 70 seconds, a vacuum degree of −700 mmHg, and a maximum resin temperature of 305 ° C. did. Polymer ηr = 2.5,
White pellets with a polymer melting point of 282 ° C. were obtained. The polymerization conditions and measurement results are shown in Table 1.

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

Example 2 <3 tanks, using container for salt preparation and concentration process> After dodecamethylenediamine, terephthalic acid, hexamethylenediamine and adipic acid were charged into the container for salt preparation process and nitrogen substitution was sufficiently performed. , 110 ℃, 0.5kg
Salt preparation was performed under stirring at / cm ² -G.

A total of 30 kg of the prepared salt, acetic acid and ion-exchanged water was transferred to a pre-heated batch type polymerization tank of 0.10 m ³ at a raw material composition ratio of Table 1 and a concentration of 60%, and the content was 130 ° C. The pressure to 3.0 kg / cm ² -G,
It was concentrated to a concentration of 80% by weight in a concentration time of 2.0 hours.

This solution was transferred to another batch polymerization tank, and after adding sodium hypophosphite, the temperature was raised to 270 ° C. over 3.5 hours with stirring, and the polymerization pressure was 17 kg / cm ^2-. G The reaction was completed by maintaining it at 270-275 ° C for an additional 30 minutes. Discharged ion-exchanged water by a metering pump 3
It was supplied at a rate of 1 / hr, and the operation was performed for 1 hour while maintaining the water vapor pressure at 12 kg / cm ² -G.

The obtained primary condensate was vacuum-dried at 100 ° C. for 24 hours, and then melted to a high degree of polymerization by melting in a 30 mmφ vent type twin-screw extruder at a residence time of 65 seconds, a vacuum degree of −700 mmHg, and a maximum resin temperature of 305 ° C. did. Polymer ηr = 2.5,
White pellets with a polymer melting point of 295 ° C. were obtained. The polymerization conditions and measurement results are shown in Table 1.

Example 3 <4 tanks, 2 containers for salt preparation process
Machine, using one container for concentration process> Hexamethylenediamine and terephthalic acid, and hexamethylenediamine and isophthalic acid are charged in separate containers for salt preparation process,
After sufficient nitrogen replacement, 110 ° C, 0.5 kg / cm ^2-
G, salt was prepared individually under stirring. A total of 30 kg of each adjusted salt, acetic acid, and ion-exchanged water was charged into a batch type concentration tank of 0.10 m ³ with a raw material composition ratio of Table 1 and a solid content concentration of 65%, the temperature was raised to 160 ° C., and the pressure was adjusted to 6. 0 k
It was concentrated to a concentration of 80% by weight under a concentration of g / cm ² -G and a concentration time of 4.0 hours. This solution was transferred to another batch polymerization tank, phosphoric acid was added, and then the temperature was raised to 270 ° C. over 3.5 hours with stirring, and the polymerization pressure was set to 25 kg / cm ² -G. 2 more 30 minutes
Maintained at 70-275 ° C to complete the reaction. For the discharge, ion-exchanged water is supplied by a metering pump at a rate of 3 l / hr,
It was carried out for 1 hour while keeping the water vapor pressure at 15 kg / cm ² -G. After vacuum-drying the obtained primary condensate at 100 ° C. for 24 hours, a 30 mmφ bent type twin-screw extruder was used for a residence time of 65 seconds, a vacuum degree of −700 mmHg, and a maximum resin temperature of 320.
The degree of polymerization was increased by melting at ℃. White pellets having a polymer ηr = 2.5 and a polymer melting point of 304 ° C. were obtained. The polymerization conditions and measurement results are shown in Table 1.

Example 4 <3 tanks, container for salt preparation step, container for concentration step> Using the method of Example 2 , salt preparation, concentration, polymerization and high degree of polymerization were carried out with the composition shown in Table 1. The results are shown in Table 1. By the methods of Examples 1 to 4 , polyamides having excellent tensile strength, tensile elongation and chemical resistance were obtained.

Comparative Example 1 <1 tank> The same raw material as in Example 1 was used, salt preparation and concentration were carried out in 1 tank of the polymerization layer, and the pressure was 17.0 kg / cm ² -G. Then, polymerization was performed. ηr = 1.4, melting point 275 ° C.
A primary condensate of

The primary condensate was vacuum dried at 100 ° C. for 24 hours, and then, it was placed in a 30 mmφ vent type twin-screw extruder for a residence time of 75 seconds, a vacuum degree of −700 mmHg, and a maximum resin temperature of 30.
The degree of polymerization was increased by melting at 5 ° C. ηr = 2.5, melting point 278
A white pellet of ° C was obtained. The polymerization conditions and measurement results are shown in Table 1.

Comparative Example 2 <Relative viscosity of primary condensate is out of range> Polymerization was carried out according to the method of Example 1 under the conditions shown in Table 1. A primary condensate of ηr = 2.6 and a melting point of 275 ° C. was obtained.

This primary condensate was vacuum dried at 100 ° C. for 24 hours, and then, it was placed in a 30 mmφ vent type twin-screw extruder for a residence time of 70 seconds, a vacuum degree of −700 mmHg, and a maximum resin temperature of 30.
The degree of polymerization was increased by melting at 5 ° C. ηr = 3.0, melting point 271
C. yellow pellets were obtained. The polymerization conditions and measurement results are shown in Table 1.

When only one tank was used for the polymerization of the primary condensate (Comparative Example 1), the tensile strength, elongation and chemical resistance were poor, and the relative viscosity of the primary condensate was high (Comparative Example). 2) was inferior in tensile strength and elongation.

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[Table 1]

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EFFECT OF THE INVENTION By adopting the production method of the present invention, it is possible to provide a high-quality polyamide which can be polymerized without applying excessive heat and is excellent in tensile strength, tensile elongation and chemical resistance. You can

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08G 69/00-69/50

Claims (6)

(57) [Claims] 1. A method for producing a polyamide containing a terephthalic acid structure, wherein the relative viscosity (ηr) of a 1% sulfuric acid solution at 25 ° C. is 1.04 to 2.5 via three or more batch type containers. after obtaining the primary condensation product, a further production how polyamides characterized by high polymerization degree
Therefore, the batch type container should be used at least for the raw salt preparation process.
From the container for the raw material, the container for the concentration process of the raw materials and the container for the polymerization
A method for producing a polyamide, comprising: 2. A raw material concentration step, at 90 to 220 ° C., within 10 hours, The process according to claim 1 Symbol placement of polyamide, characterized in that the concentration of the raw material is to 70% or more. 3. A process according to claim 1 or 2 Symbol placement of polyamide, wherein the melting point of the polyamide is in the range of 230 ° C. to 340 ° C.. 4. A polyamide be one having an aliphatic diamine structure, a method of producing the polyamide according to one of claims 1 to 3 have deviation, wherein the number of carbon atoms of the aliphatic diamine is from 4 14 . 5. The structural unit (I): wherein the polyamide is a copolyamide. And at least one structural unit selected from structural units (II) to (IV): [Chemical 3] [Chemical 4] The method according to claim 4 Symbol mounting polyamide, characterized in that those having a repeating unit consisting of. 6. A process according to claim 1-5, wherein the polyamide which comprises using the phosphorus-based polymerization catalyst.