KR100432061B1 - Method for producing polyamide 12 having excellent mechanical properties through reaction extrusion process in short time - Google Patents

Abstract

PURPOSE: Provided is a method for producing polyamide 12 having excellent mechanical properties through a continuous reaction extrusion process in one twin-screw extruder in a relatively short reaction time. CONSTITUTION: The method for producing polyamide 12 comprises the steps of: adding 0.05-1.0 moles of an alkali metal-based catalyst and 0.05-1.0 moles of an acetylated caprolactam cocatalyst to 100 moles of polymerizable cyclic lactam monomers which are formed of 12 carbon molecules and are capable of producing polyamide; and carrying out continuous polymerization of the above reaction mixture in a twin-screw extruder at a polymerization temperature of 90-270 deg.C.

Description

Method for producing polyamide 12 by reaction extrusion

The present invention relates to a method for producing polyamide 12 by a reaction extrusion process, and more particularly, to a polyamide 12 resin having a shorter reaction time and excellent mechanical properties than a polyamide resin having the same molecular weight produced by a conventional condensation reaction. It relates to a manufacturing method.

U.S. Patent No. 3,793,255 describes a process for the continuous polymerization of polyamides through spiral tubes. Since this method is a synthetic method by spiral tube, it is difficult to directly extrude or spin the polymer flowing out through the reaction tube.

In addition, US Pat. No. 3,484,414 describes a technique for synthesizing polyamides through an extruder, in which a reaction time is shortened by using dicaproiactim ether as a subcatalyst to obtain a high molecular weight polymer within a short time. However, this method has a problem in that the reaction proceeds only when the reaction temperature is raised to 300 ° C. due to the stability of the dicaproic acid thiether.

In the present invention, in order to solve the above problems, to provide a method of polymerization and continuous extrusion of polyamide 12 by using a single twin screw extruder, as a result of the polyamide resin of the same molecular weight produced by the conventional condensation reaction The method for producing a polyamide resin having a short reaction time and excellent mechanical properties has been completed.

The present invention adds 0.05 to 1.0 moles of alkali metal based catalyst and 0.05 to 1.0 moles of acetylated caprolactam subcatalyst to 100 moles of monomer to a polymerizable cyclic lactam monomer composed of 12 carbon molecules capable of producing polyamide. It is a method for producing polyamide 12, which is prepared by continuously polymerizing at a polymerization temperature of 90 to 270 ° C in a twin screw extruder.

Hereinafter, the present invention will be described in more detail.

In the present invention, a polymerizable cyclic lactam consisting of 12 carbon molecules capable of producing polyamide as a monomer is used, and lauryl lactam is preferably used.

In the present invention, an alkali metal was used as a catalyst, and an acetylated caprolactam was used as a subcatalyst. It is most preferable to use sodium metal among the alkali metals as the catalyst, and normal acetyl caprolactam in the acetylated caprolactam can be obtained as the secondary catalyst. It is preferable to use an alkali metal catalyst in the range of 0.05-1.0 mol with respect to 100 mol of monomers, and it is preferable to use the acetylated caprolactam subcatalyst in the range of 0.05-1.0 mol with respect to 100 mol of monomers.

Under the above conditions, when the amount of the catalyst and the subcatalyst is less than 0.05 mole, a high molecular weight polymer cannot be obtained. When the amount of the catalyst and the subcatalyst is more than 1.0 mole, the amount of the residual catalyst increases, resulting in a decrease in viscosity during processing.

In the present invention, one twin screw extruder is used, in which a mixture of 0.5 mol of a catalyst material is added to a molten monomer of 1 mol and a mixture of 3 mol of monomer is mixed into a mixture of 0.5 mol of a cocatalyst to 1 mol of a monomer. Thereafter, the kneaded mixture is introduced together with nitrogen or argon gas into the inlet of the twin screw extruder to initiate the reaction.

The twin screw extruder can adjust the temperature range at each site as follows: In order to successfully add the monomer, catalyst and cocatalyst in the powder state, the temperature of the inlet is maintained between 90 and 200 ° C, which has a melting point of 180 It is because it is ° C. In addition, since the crystal melting temperature of polyamide 12 is 180 ° C., the temperature of the latter part of the extruder barrel and the die temperature should be maintained at 180 ° C. or higher to extrude the polyamide 12.

In the present invention, a process capable of polymerization and continuous extrusion of caprolactam using one twin screw extruder, the reaction time of which is shorter than that of the same molecular weight polyamide resin produced by the conventional condensation reaction, and has good mechanical properties It relates to a resin manufacturing process. That is, the polyamide 12 is synthesized by continuous anion reaction at low temperature, and the mixture of monomer, catalyst and subcatalyst is put in the inlet of the twin screw extruder and reacted within 4 minutes by the synthesis method in the temperature range of 70 to 270 ° C. This is the reaction process to complete.

If desired, the extruded polymer can be continuously extruded into pipes, hoses, films, etc. by changing the die shape.

The present invention will be described with reference to the following examples. However, the present invention is not limited to the following examples.

Examples 1-6

Lauryllactam flake from ELF Atochem, France, was used as a monomer, sodium was used as a catalyst, and normal acetylcaprolactam was used as a subcatalyst. Rilsan AMNOR from ELF Atochem, a commercial polyamide, was used for physical property comparison.

8 mol of lauryl lactam monomer was kneaded in a mixture of a sodium catalyst according to Table 1 in a molten 1 mol lauryl lactam monomer and a mixture of a normal acetyl caprolactam subcatalyst according to Table 1 in a 1 mol lauryl lactam monomer. Each was made into Examples 1-6. The kneaded mixture was introduced with nitrogen or argon gas into the inlet of the twin screw extruder. At this time, the twin screw extruder can be divided into four parts as follows, the temperature range of each part is as follows.

The twin screw extruder was manufactured by Werner & Pfleiderer of Germany, and used ZSK-25 model with 6 heating zones with a length and diameter ratio of 42.

The screw speed was 50 to 350 rpm, and the discharge amount was maintained at 2 kg and 4 kg per hour, and the polymer extruded was pelleted with a pelletizer to collect unreacted monomers and the reaction degree was measured.

The conversion rate was measured to know the degree of reaction. The conversion rate was 100 g of polyamide 12 dissolved in m-cresol, extracted with methanol, extracted with Soxhlet, and washed with unreacted monomers. The decision was made.

The molecular weight was measured by Gel Permeation Chromatography (GPC). The solvent was m-cresol, and the comparative number average molecular weight was measured using polyamide having a number average molecular weight of 20,000 as a standard sample.

Relative viscosity was measured using sulfuric acid as a solvent, melt index and mechanical properties were measured according to ASTM.

The measured results are shown in Tables 1 and 2, respectively.

Comparative Examples 1 and 2

A polyamide 12 polymer was prepared in the same manner as in the above example, except that the contents of the catalyst and the subcatalyst were used according to Table 1 below.

Tensile strength, tensile elongation, and conversion of the prepared polymers were measured and listed in Table 1, and the number average molecular weight, relative viscosity, and melt index were measured, and the results are shown in Table 2.

TABLE 1

TABLE 2

According to the process of the invention, the monomers can be polymerized with polyamide 12 in a short time and extruded in a continuous process. Polyamide 12 polymerized according to the present invention has a shorter reaction time and better mechanical properties than polyamide resins of the same molecular weight prepared by the conventional condensation reaction. , Can be used as sporting goods.

Claims (1)

To a polymerizable cyclic lactam monomer consisting of 12 carbon molecules capable of producing a polyamide, 0.05 to 1.0 moles of alkali metal based catalyst and 0.05 to 1.0 moles of acetylated caprolactam subcatalyst are added to 100 moles of monomer and a twin screw extruder. A process for producing polyamide 12, characterized in that the polymerization is carried out continuously at a polymerization temperature of 90 to 270 캜.