JPH0325459B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides hexamethylene diamine (HMDA),
The present invention relates to a method for producing a composition of glass fibers and a crystalline copolyamide made from a mixture of terephthalic acid (TA) and ε-caprolactam (CL). Conventionally, polyamide (nylon 6) from CL,
Polyamide (nylon 6.6) made from HMDA and adipic acid (AA) has a wide range of uses as a molded product, but its melting point (Tm) is 215℃ and 259℃, respectively, and even if glass fiber is inserted, there is a limit to the heat distortion temperature. The melting point of each is just below. Recently, as heat-resistant applications have increased, fully aromatic polyamides, polyamideimides, polyimides, polyethers, polyesters, etc. have begun to appear on the market, but they have poor processability and expensive raw material monomers. Since the polymerization method is complicated,
It is several times more expensive than nylon 6, nylon 66, etc. The present inventors have conducted intensive studies on resin compositions that have improved heat resistance than nylon 6 and nylon 66, are inexpensive raw materials, and can be melt-molded, and have found specific compositions of HMDA/TA/CL, HMDA/TA/ CL／
Isophthalic acid (IA) or HMDA/TA/CL/
We have proposed a highly crystalline copolyamide consisting of AA, but in order to polymerize this highly crystalline copolyamide, it is difficult to polymerize it using conventional single-stage polymerization methods such as nylon 6 and nylon 66, which use an autoclave under high pressure. Obtaining polymers has proven difficult. That is, the melting point of the highly crystalline copolyamide of the present invention is 100°C higher than that of nylon 6, and higher than that of nylon 66.
Because it is 40-50℃ higher than conventional nylon 6
Using a polymerization method similar to that used for nylon 66, it is extremely difficult to produce products with stable quality both industrially and practically. For example, if nylon 66 is polymerized at a temperature of 270 to 290°C, nylon 66 can be polymerized in a molten state in an autoclave, but this polymer has a low melting point.
Since the temperature is 300°C or higher, it is difficult to polymerize in the molten state unless the temperature is 330°C or higher. The inventors of the present invention conducted extensive studies on this point and found that after first producing a prepolymer in a conventional pressure vessel such as an autocube or a flash reactor, the degree of polymerization can be controlled more easily and in a shorter time using a heated melt-kneading device. We found a way to increase this and arrived at the present invention. That is, the present invention uses the following iterative component In the method of polymerizing a crystalline copolyamide consisting of (A) 65-95% by weight and (B) 35-5% by weight, first, reduction is performed using a pressure vessel such as an autoclave or a flash reactor. Viscosity (measured at 30℃ at a concentration of .5g/100ml in concentrated sulfuric acid)
After polymerizing a prepolymer with a concentration of 0.05 to 0.40 dl/g, the ring base viscosity is reduced using a heated melt kneading device such as a single screw or twin screw extruder equipped with one or more vent ports.
100 parts by weight of aromatic copolyamide further polymerized to a concentration of 0.8 dl/g or more, and glass fiber 5-
50 parts by weight of an aromatic copolyamide composition. In implementing the present invention, HMDA, TA,
The preparation ratio of CL is the following iterative component In this case, (A) should be added at 65-95% by weight and (B) at 35-5% by weight. In terms of quality, the composition according to the present invention preferably has a high melting point and excellent heat resistance, but when the aromatic copolyamide is heated to 360° C. or higher, thermal decomposition due to heating, melting and kneading cannot be ignored. Therefore, the melting point of the aromatic copolyamide must be kept below 360°C. In the present invention, if (A) exceeds 95% by weight, the melting point of the aromatic copolyamide will be 360° C. or higher, and thermal decomposition will occur during heating, melting, and kneading, which is undesirable. The method for producing the copolyamide prepolymer of the present invention may be either continuous or batch polymerization, and methods in which raw materials are heated and polymerized under pressure, normal pressure, or reduced pressure can be adopted, but for example,
A 30 to 60% by weight aqueous solution of HMDA-TA nylon salt was charged into a polymerization reactor together with CL, and after the reactor was completely replaced with nitrogen gas, it was heated and the water vapor pressure was kept at 5 to 10 Kg/ ^cm2 . The reaction may be carried out at 280°C, and then the water vapor may be removed and polymerization may be carried out at normal pressure for 30 minutes to 4 hours. In addition, various additives such as a polymerization degree regulator, a heat stabilizer, a weather resistant agent, an antistatic agent, a pigment, and a flame retardant may be added during the polymerization. Prepolymer production is done by batch method, batch-continuous method,
It may be completely continuous, consisting of one or more agitated tank reactors of suitable design. The prepolymer product at this stage is a copolyamide oligomer with a reduced viscosity (measured at 30° C. in concentrated sulfuric acid) of 0.05 to 0.4 dl/g. If the reduced viscosity of the prepolymer is less than 0.05 dl/g, it will be difficult to feed it to the extruder in the next step, and if it exceeds 0.40 dl/g, it will be difficult to produce a uniform prepolymer using an autoclave or the like. Batch production of the prepolymer may be carried out in any suitably designed stirred reactor capable of handling high viscosity materials. Feed materials consisting of acid, amine and additives are charged to the reactor at 80°C. The water content of the resulting solution should not be more than 15% by weight. The temperature is then raised to 230-280°C as quickly as possible. After reaching the target temperature, the pressure is reduced to atmospheric pressure over a period of 5 to 120 minutes. The polymer is then drained from the reactor and collected under an inert atmosphere. Prepolymers can also be produced by the following method. Condensing salts or prepolymers that are readily sprayed with controlled means to provide an aerosol mist at about 0-30 atmospheres, wherein the polymerization is carried out at a wall temperature of about 200°C to about 500°C and a melt temperature of about 170°C to about 400°C. Examples include methods carried out in a flash reactor designed to provide a high amount of heat transfer at a temperature and comprising retaining the polymer in the reactor for a period of from about 0.1 seconds to about 30 seconds. The prepolymer prepared by the above method was heated and melted using a heating melt kneading device until the reduced viscosity was 0.8 dl/g.
Polymerization is further carried out in the manner described above to produce the desired high polymer. If the reduced viscosity is less than 0.8 dl/g, the resulting aromatic copolyamide will have insufficient physical properties such as mechanical properties. Examples of melt-kneading methods include plastomills, kneaders, Brabenders, single-screw extruders, twin-screw extruders, etc., and preferably extruder type ones equipped with one or more vent ports. Melt-kneading is preferably carried out in a state where the prepolymer does not come into contact with air, ie, oxygen. For example, the prepolymer may be melt-kneaded in a nitrogen atmosphere. Approximately 300
When melt-kneading is performed at ~350°C, the condensation reaction progresses and water comes out as gas. Note that during melt-kneading, organic or inorganic fibers or fillers may be kneaded at the same time. The glass fibers may be added at the same time as the above-mentioned melt-kneading, or the glass fibers may be added to the above-mentioned kneaded material and further melt-kneaded. The effect of polymerizing the prepolymer of the present invention in a system containing glass fibers is significant. The invention will be illustrated with reference to the following examples. Example 1 and Comparative Example 1 160 parts of a 50% aqueous solution of HMDA/TA nylon salt
20 parts of CL was charged into a polymerization reactor (autoclave). After the reactor was completely purged with nitrogen gas, it was heated, and polymerization was carried out at 240 to 260° C. while maintaining the water vapor pressure at 10 Kg/cm ² . After further pressurization, water vapor is removed and 2 to 4
Polymerized for hours. The obtained polymer was sufficiently cooled, taken out, and pulverized using a pulverizer. Next, this powder was sufficiently dried at 90°C or lower so that the moisture content was 0.1% or lower. The reduced viscosity at this time is
It was 0.15 dl/g. There is one vent port for drying the prepolymer2.
The reaction was carried out in a screw extruder, and the polymer that came out of the nozzle was immediately cooled in water and cut into pellets. The temperature of the extruder is 320-330℃,
The screw rotation speed was 10 to 20 rpm, the average residence time of the polymer was about 8 minutes, the vent port was open, and the hopper port was in a nitrogen atmosphere. The reduced viscosity of this polymer is approximately
It was 1.0 dl/g. The obtained polymer pellets were sufficiently dried at 90° C. or lower so that the moisture content was 0.1% or less, and then blended with glass fibers in the composition shown in Table 1 and granulated using a twin-screw extruder. The granulation temperature was about 300-340°C. Next, a test piece was produced using a normal injection molding machine. Injection pressure approximately 1000Kg/cm ² , mold temperature approximately 100~
The temperature was 200°C and the barrel temperature was 300-350°C. The color of the molded product was white and had a good color. Comparative Examples 2 to 3 Polymerization was carried out in an autoclave at 280 to 300°C in the same manner as in Example 1, followed by granulation and molding. This polymer is slightly yellow in color and has a reduced viscosity of approx.
It was 1.0. The color of the molded product was yellowish brown. The effects of the prepolymer polymerization method are compared with and without the addition of glass fibers. Comparing the difference between Example 1 and Comparative Example 3 and the difference between Comparative Example 1 and Comparative Example 2, it can be seen that the effect of the prepolymer polymerization method is greater in the system in which glass fibers are added. 【table】

Claims (1)

[Claims] First-order repetitive component In the method of polymerizing a crystalline copolyamide consisting of (A) 65-95% by weight and (B) 35-5% by weight, first, reduction is performed using a pressure vessel such as an autoclave or a flash reactor. Viscosity (measured at 30℃ at a concentration of 0.5g/100ml in concentrated sulfuric acid)
After polymerizing a prepolymer with a concentration of 0.05 to 0.40 dl/g, the reduced viscosity is reduced using a heated melt kneading device such as a single-screw or twin-screw extruder equipped with one or more vent ports.
100 parts by weight of aromatic copolyamide further polymerized to a concentration of 0.8 dl/g or more, and glass fiber 5-
50 parts by weight of an aromatic copolyamide composition.