KR20020048806A - Process for preparing a polyamide copolymer for high speed spinning - Google Patents

Abstract

PURPOSE: Provided is a method for preparing a copolymer suitable for high speed spinning, wherein a small amount of polyamide66 polymer is copolymerized with polyamide6 polymer under continuous process to delay a crystallization rate of polymer. CONSTITUTION: The method comprises polymerizing eta-caprolactam and hexamethylene diaminoadipate to produce a polyamide copolymer, characterized in that the second melting furnace for storing a slurry of hexamethylene diaminoadipate and eta-caprolactam, apart from the first melting furnace for eta-caprolactam which is a main material, is fitted on the top of polymerizing bath, with the proviso that stirrer is fitted to continuously stir the slurry, and an amount of hexamethylene diaminoadipate in the final copolymer is 0.3-10 wt%. A static mixer is fitted in a transferring pipe which connects the polymerizing bath and the second melting furnace.

Description

Process for preparing a polyamide copolymer for high speed spinning

The present invention relates to a process for preparing polyamide copolymers suitable for high speed spinning prepared by slowing down the crystallization rate of polyamide 6 polymer.

Polyamide-6 is a polymer produced through ring opening and condensation of ε-caprolactam.

It is mainly used for textiles, injection molded products, extruded products, etc., and it gives the proper level of molecular weight and crystallization properties depending on the intended use, and sometimes improves functionality by mixing inorganic materials.

Among them, it is particularly important that the fiber polyamide has suitable properties for spinning. Such properties include molecular weight, molecular weight distribution, melt viscosity, oxidation degree, heat of fusion and crystallization rate.

Polyamide-6 is generally characterized by melting around 220 ° C and recrystallization around 180 ° C upon cooling, but by reacting together mono or dicarboxylic acid, mono or diamine other than ε-caprolactam alone or in combination Deformation of the polymer chains results in changes in melting, crystallization temperature, rate, calorific value, and the like.

Such modifications are carried out for the special use of polymer polymers. In particular, in order to obtain polymers requiring transparency, polyamide is obtained through copolymerization of hexamethylenediaminoadipate, which is a raw material of polyamide-66, with ε-caprolactam. The production of transparent polyamides with suppressed crystallization of is widely made.

However, the production of polyamide with such a slow crystallization rate requires a step of concentrating the solution of hexamethylenediaminoadipate and is difficult to produce in a continuous process.

In general, the polymerization by the continuous process of polyamide-6 is carried out to 0.1 to 3.0 parts by weight of water and a base compound having a carboxylic acid or an amine group as a polymerization degree regulator to induce ring-opening polymerization to ε-caprolactam as a raw material. It is added within the weight part, and the required talc, titanium dioxide, etc. are added according to the use, melted at a temperature of 90 ° C. to 100 ° C., stored, and then put into a polymerization tower to carry out continuous polymerization.

However, hexamethylenediaminoadipate has excellent solubility in water but does not dissolve in ε-caprolactam, the main ingredient.

In addition, because the sedimentation is very high, it does not disperse in the molten ε-caprolactam, so it is precipitated in the molten raw material storage tank, there is a problem that it is impossible to quantitatively add to the subsequent process.

In order to solve such a problem, European Patent 96/05514 et al. Set up a dissolution tank of hexamethylene diamino adipate separately, dissolved with water, mixed with ε-caprolactam, heated and concentrated, and then introduced into a continuous process. However, when the solution of hexamethylene diamino adipate is mixed in the ε-caprolactam melt, reprecipitation occurs in the transport pipe, which causes the problem of inhibiting transportation. Enemy costs are lost.

In addition, the high temperature and high pressure is maintained for the concentrated transfer of hexamethylene diamino adipate. In this case, the high temperature and high pressure concentrate is sprayed on the upper part of the atmospheric pressure reactor near atmospheric pressure, resulting in uneven physical properties and unstable process conditions. There was this.

In the present invention, in preparing a polyamide polymer suitable for high-speed spinning, ε-caprolactam and hexamethylene diamino adipate are made to be stably fed to the polymerization reactor so that the transfer of hexamethylene diamino adipate is performed smoothly. The technical problem is to provide a method for stably preparing a copolymer with.

In order to solve the above problems, the present invention provides a method of mounting a melting tank for forming a slurry with a high concentration of hexamethylene diamino adipate separately from a transfer pipe for dissolving ε-caprolactam and transporting it to a reaction tower. Used.

The slurry of hexamethylene diamino adipate is 60-90 weight% of epsilon caprolactam, and 10-40 weight% of hexamethylene diamino adipate.

The melting tank mounted on the top of the reactor is provided with a heating device and a temperature control device for dissolving the epsilon caprolactam and a stirrer for preventing the sedimentation of hexamethylenediaminoadipate dispersed in the molten epsilon caprolactam.

Thus, the raw material part into which the additives, such as water used as a catalyst of reaction and the epsilon caprolactam, the hexamethylene diamino adipate and the melt slurry of the epsilon caprolactam were adjusted according to the final composition of the reactant. Are each introduced into the top of the reactor.

A static mixer should be installed in the transfer pipe between the slurry of ε-caprolactam and hexamethylenediaminoadipate and the top of the reactor.

By installing the static mixer, it is possible to achieve uniform movement to the upper part of the reactor by preventing the settling of the slurry generated in the transfer pipe.

By using this method, it is possible to prevent excessive investment of equipment cost compared to the installation of agitator and static mixer in the dissolution tank and the transfer pipe for the total input amount, and to reduce the actual slurry movement distance, thereby reducing the possibility of sedimentation of hexamethylene diamino adipate. Minimize the effect.

The total amount of hexamethylene diamino adipate added is 0.3 to 10.0% by weight, more preferably 0.5 to 3.0% by weight based on the total polymer.

If the amount of hexamethylene diamino adipate is less than 0.3% by weight, there is little effect on the crystallization rate, and thus the expected effect cannot be achieved. have.

The storage tank of the raw material is filled with nitrogen to block the contact with oxygen, and the temperature of the storage tank is maintained at 90 ° C to 100 ° C.

If kept below 90 ° C., the epsilon caprolactam may be solidified. If it exceeds 100 ° C., the raw material may be oxidized or water used as a reaction initiator may be vaporized.

Example 1

(1) The temperature of the first melting tank equipped with the stirrer is 95 ° C, and 99.9 g of ε-caprolactam, 2 g of water, and 0.1 g of acetic acid are added to the melting tank, followed by stirring to dissolve.

② The temperature of the second melting tank equipped with a stirrer is 95 ℃, and after stirring ε-caprolactam 90.0g, 2g water, 0.09g acetic acid and 10.0g hexamethylene diamino adipate into the melting tank and stirring Dissolve.

③ The dissolved raw material is introduced into the reaction tank at the inflow rate of 2.7Kg / min in the first melting tank and introduced into the reaction vessel at the inflow rate of 0.3Kg / min in the second melting tank.

At this time, a static mixer is installed in the transfer pipe transferred from the second melting tank to the reaction tank, and the temperature of the transfer line is 120 ° C.

④ The polymerization tank is maintained at atmospheric pressure and polymerization is carried out at 240 ° C. with a residence time of 20 hours.

⑤ The polymerized product is cut into chips by cooling with cooling water.

⑥ The polymer made of chips is extracted with water at 95 ℃ for 20 hours to remove unreacted monomers and oligomers.

⑦ The extracted chips are dried with hot air nitrogen.

Example 2

(1) The amount of hexamethylene diamino adipate in (2) of Example 1 shall be 20.0 g with respect to 80.0 g of epsilon caprolactam.

② The flow rate into the reaction tank of ③ of Example 1 shall be 2.85 Kg / min from the first melting tank and 0.15 Kg / min from the second melting tank.

③ The rest of the process is the same as in Example 1.

Example 3

(1) The amount of hexamethylene diamino adipate in (2) of Example 1 is 40.0 g with respect to 60.0 g of epsilon caprolactam.

② The flow rate into the reaction tank of ③ of Example 1 shall be 2.925 Kg / min from the 1st melting tank and 0.075Kg / min from the 2nd melting tank.

③ The rest of the process is the same as in Example 1.

Example 4

① The flow rate into the reaction tank of ③ of Example 1 shall be 2.85 Kg / min from the 1st melting tank, and 0.15Kg / min from the 2nd melting tank.

③ The rest of the process is the same as in Example 1.

Example 5

① The flow rate into the reaction tank of ③ of Example 1 shall be 2.10 Kg / min from the 1st melting tank, and 0.90Kg / min from the 2nd melting tank.

② The rest of the process is the same as in Example 1

Example 6

(1) The amount of hexamethylene diamino adipate in (2) of Example 1 is 40.0 g with respect to 60.0 g of epsilon caprolactam.

② The flow rate into the reaction tank of ③ of Example 1 shall be 2.25Kg / min from the first melting tank and 0.75Kg / min from the second melting tank.

③ The rest of the process is the same as in Example 1.

Comparative Example 1

① The flow rate into the reaction tank of ③ of Example 1 shall be 3.00 Kg / min from the 1st melting tank, and 0.00Kg / min from the 2nd melting tank.

② The rest of the process is the same as in Example 1.

Comparative Example 2

① Agitator is not installed in the 2nd melting tank of ② of Example 1.

② The rest of the process is the same as in Example 1.

In this case, sedimentation of hexamethylene diamino adipate rapidly occurred in the second melting tank, so that transfer for polymerization could not proceed.

Comparative Example 3

(1) The amount of hexamethylene diamino adipate in (2) of Example 1 is 50.0 g based on 50.0 g of ε-caprolactam.

② The inflow rate into the reaction tank of ③ of Example 1 shall be 2.94 Kg / min from the 1st melting tank, and 0.06Kg / min from the 2nd melting tank.

③ The rest of the process is the same as in Example 1.

In this case, the content of the non-melt in the slurry in the second melter was too high, so that normal dispersion and transport could not be performed, and thus polymerization could not be performed.

Comparative Example 4

① The flow rate into the reaction tank of ③ of Example 1 shall be 2.95 Kg / min from the 1st melting tank, and 0.05Kg / min from the 2nd melting tank.

② The rest of the process is the same as in Example 1.

Measurement of the crystallization rate

The polymer obtained through the Comparative Examples and Examples was measured by the following method using a differential scanning calorimeter (DSC).

① Laminate the dried polyamide polymer in differential scanning calorimeter, accurately weigh 5 ~ 10mg into sample pan, and heat up to 250 ℃ at the rate of 10 ℃ / min under nitrogen atmosphere and measure the change of calorie. Measure the heat of fusion.

At this time, the melting point is the peak point of the endothermic peak due to melting.

② After holding at 250 ℃ for 5 minutes, lower the temperature to room temperature at the rate of 10 ℃ / min, and measure the change of calorie to measure the crystallization temperature and crystallization calorie value according to cooling.

At this time, the crystallization temperature is taken as the peak point of the exothermic peak due to the crystallization.

③ In the same manner as in ①, increase the temperature to 250 ℃ and lower the temperature to 195 ℃ at the rate of 80 ℃ / min.

④ Measure at the temperature of 195 ℃ and measure the change of calorie and measure the crystallization rate.

At this time, the crystallization rate is the time corresponding to half the heat of the total exothermic peak.

<Table 1. Result Physical Properties of Examples and Comparative Examples>

Composition (% by weight) of the second melting tank 1st molten bath input amount (Kg / min) 2nd melt bath input amount (Kg / min) Composition of hexamethylene diamino adipate in the polymer (wt%) Melting Point (℃) Crystallization temperature (℃) Crystallization rate (min) Remarks ε-caprolactam Hexamethylenediaminoadipate Example 1 90 10 2.700 0.300 1.0 219.1 179.1 3.5 Example 2 80 20 2.850 0.150 1.0 219.1 178.9 3.5 Example 3 60 40 2.925 0.075 1.0 219.0 179.0 3.6 Example 4 90 10 2.850 0.150 0.5 219.6 179.4 3.2 Example 5 90 10 2.100 0.900 3.0 215.0 176.2 7.0 Example 6 60 40 2.250 0.750 10.0 206.8 165.2 - Comparative Example 1 90 10 3.000 0.000 0.0 220.8 182.1 2.5 Comparative Example 2 90 10 2.700 0.300 1.0 - - - Polymerization not possible Comparative Example 3 50 50 2.700 0.300 5.0 - - - Polymerization not possible Comparative Example 4 90 10 2.950 0.050 0.17 220.6 181.9 2.7

The present invention copolymerizes hexamethylene diamino adipate with ε-caprolactam to produce a polyamide polymer suitable for high-speed spinning in which the crystallization rate of the copolymer is delayed and the crystallization temperature is lowered. By providing the input equipment can solve the problem caused by the sedimentation of hexamethylene diamino adipate, there is an advantage that can reduce the inefficiency of stirring the whole raw material.

Claims (2)

In preparing a polyamide copolymer by polymerizing ε-caprolactam and hexamethylene diamino adipate, hexamethylene diamino adipate and ε-caprol are separate from the first melting tank of ε-caprolactam which is the main raw material at the top of the polymerization tank. A second melting bath for storing the slurry with the lactam is provided, but agitator is provided to continuously stir the slurry, so that the amount of hexamethylenediaminoadipate in the final copolymer is 0.3 to 10% by weight. Method for producing a polyamide copolymer suitable for high speed spinning characterized in that. The method for producing a polyamide copolymer suitable for high-speed spinning according to claim 1, wherein a static mixer is installed in a transfer pipe connecting the polymerization tank and the second melting tank.