Process for producing polyamide containing an amide-based molecular weight regulator and polyamide produced thereby

Abstract

The present invention provides a method for producing polyamides, which includes an amide-based molecular weight regulator, and which easily controls the molecular weight of polyamides to provide a narrow molecular weight distribution, thereby preventing an increase in molecular weight due to a basic intermediate produced in anionic polymerization and side reactions occurring under high-temperature polymerization conditions. The present invention also provides polyamides produced thereby. [Selected Figure] Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing polyamides containing an amide-based molecular weight regulator and polyamides produced thereby, and more particularly to a method for producing polyamides containing an amide-based molecular weight regulator that easily regulates the molecular weight of polyamides to have a narrow molecular weight distribution and prevents an increase in molecular weight due to a basic intermediate produced in anionic polymerization and side reactions occurring under high temperature polymerization conditions, and relates to polyamides produced thereby. [Background technology]

[0002] Polyamide resin is a linear polymer bonded by amide (-NHCO-) ​​bonds, and has excellent physical properties such as toughness, abrasion resistance, oil resistance, and solvent resistance, and is easy to melt mold, so it is widely used as clothing material, industrial fiber, engineering plastics, etc. Depending on the molecular structure, polyamides can be classified into aliphatic polyamides, aromatic polyamides, and aliphatic ring polyamides, of which aliphatic polyamides are sometimes called nylon and aromatic polyamides are sometimes called aramid.

[0003] Such polyamides are produced by various polymerization methods, and can be broadly divided into those produced by ring-opening polymerization of lactam, such as nylon 6, those produced by polycondensation of diamines and dibasic acids, such as nylon 6,6, nylon 6,10, and nylon 4,6, and those produced by polycondensation of aminocarboxylic acids, such as nylon 11 and nylon 12. In addition, so-called copolymer nylons, such as a hybrid condensate of caprolactam and nylon 6,10 salt (hexamethylenediamine and sebacate), are being industrially produced, and various polyamides containing side chains, functional groups such as hydroxyl groups, aromatic rings, and heterocycles in the molecule are being researched.

[0004] Lactams, such as caprolactam, can be polymerized anionically. This process generally uses a catalyst and / or an initiator (also called an activator) (activated anionic polymerization). To date, the initiators or activators mainly used include diisocyanates or their derivatives.

[0005] US Pat. No. 5,399,633 describes the activated anionic polymerization of lactams to produce polyamides using polyisocyanates containing biuret groups and derived from non-aromatic diisocyanates as activators.

[0006] Patent Document 2 discloses a composition comprising, as component A, a polyisocyanurate having an average of more than 3.5 NCO functional groups, and / or a method for producing a surface coating composition using said composition.

[0007] Patent Document 3 uses uncapped polyisocyanates (thus significantly reducing reactivity) and the activator concentrations in its examples are very low (1 / 200 to 1 / 50 mole), resulting in significant delays in polymerization times.

[0008] US Pat. No. 5,999,366 uses rubber (i.e., elastomeric polymer) as a precursor of a multi-functioning activator, and therefore the resulting PA is not hard, up to 1.12 GPa. The activator has a high Mw, where a large amount of activator is required (20% or more). A mixture of difunctional and multifunctional activators is used, and therefore the resulting polyamide is not a crosslinked material.

[0009] In addition, in Patent Document 5, an anionic polymerization technique for lactam using an extruder is described in which a metering pump is installed between the extruder body and extruder die in order to obtain a constant output and uniform viscosity and physical properties, thereby attempting to mechanically solve the non-uniformity of viscosity, but this is not a fundamental solution.

[0010] Patent Document 6 points out the problem of unstable viscosity due to thermal decomposition and the formation of a structurally irregular branching structure, but only attempts to solve the problem by using additives with higher acidity to prevent decomposition of the synthesized polymer, and makes no mention of solving the non-uniform branching structure. Incidentally, Non-Patent Documents 1 and 2 refer in detail to the branching side reaction that occurs during anionic polymerization of polyamide.

[0011] In particular, Patent Document 7 introduces a solution liquid system that simultaneously contains a catalyst and an initiator (reaction accelerator) to obtain a more uniform product. It is stated that the solution system was used to obtain a uniform product with consistent quality and highly reproducible results, but there are problems with its inefficiency when applied to reactive extrusion methods, such as the problem of solvent removal. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] US4754000 (Bayer AG) [Patent Document 2] EP1091991 (BASF AG) [Patent Document 3] No. US3423372 [Patent Document 4] EP0156129 issue [Patent Document 5] US4067861 (1978) [Patent Document 6] US3878173 (1975) [Patent Document 7] US5747634 (1998) [Patent Document 8] US6713596B1 [Patent Document 9] Republic of Korea Patent No. 10-1533891 [Patent Document 10] Republic of Korea Patent No. 10-1349063 [Patent Document 11] Republic of Korea Patent No. 10-0322263 [Non-patent literature]

[0013] [Non-Patent Document 1] MP Stevens, 'Polymer Chemistry', 2nd Ed., Oxford University Press, p429(1990) [Non-Patent Document 2] G. Odian, 'Principles of Polymerization', 2nd Ed., John Wiley&Sons, p541(1981) [Non-Patent Document 3] METHOD FOR ANIONIC POLYMERIZATION OF LACTAMS(Atofina)J.Applied Polymer Science, 2003, 90, 344-351, IN-situ Formation and Compounding of Polyamide 12 by Reactive Extrusion Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention aims to solve the above-mentioned problems of the conventional technology and the technical problems that have been desired in the past.

[0015] The object of the present invention is to provide a method for producing polyamides containing an amide-based molecular weight regulator, which can easily control the molecular weight of polyamides to have a narrow molecular weight distribution and prevent an increase in molecular weight due to basic intermediates produced in anionic polymerization and side reactions occurring under high temperature polymerization conditions, and to provide polyamides produced thereby.

[0016] Another object of the present invention is to provide a method for producing polyamide containing an amide-based molecular weight regulator, which is an environmentally friendly process that does not use a solvent as a catalyst and can achieve high molecular weight polymerization with a uniform molecular weight at a low temperature and in a short polymerization reaction time compared to conventional polymerization methods, with a high conversion rate, and a polyamide produced thereby. [Means for solving the problem]

[0017] In order to achieve the above object, the present invention provides a method for producing a polyamide containing an amide-based molecular weight regulator, comprising the steps of: A method for producing a polyamide containing an amide-based molecular weight regulator by an anionic polymerization reaction, comprising the steps of: The lactam may contain 0.01 to 20 parts by weight of an alkali metal initiator, 0.3 to 10 parts by weight of a compound represented by the following Formula 1 as a molecular weight regulator, and 0.002 to 7.0 parts by weight of an activator, based on 100 parts by weight of the lactam in total.

[0018] [ka]

[0019] In the formula, R1 and R2 may be the same or different, and each is a substituent containing a heteroatom, or each is hydrogen, a linear or branched alkyl having 1 to 10 carbon atoms, a linear or branched alkenyl having 2 to 10 carbon atoms, an aryl having 6 to 20 carbon atoms, an alkylaryl having 7 to 21 carbon atoms, an arylalkyl having 7 to 21 carbon atoms, a cycloalkyl having 3 to 10 carbon atoms, an alkoxy having 1 to 10 carbon atoms, an aryloxy having 6 to 20 carbon atoms, an alkylsilyl having 1 to 10 carbon atoms, an arylsilyl having 6 to 20 carbon atoms, or a halogen, and each n is independently a rational number of 0 to 20.

[0020] In a preferred embodiment of the present invention, the molecular weight regulator is selected from the group consisting of compounds represented by the following formulas 2 to 4.

[0021] [ka]

[0022] In the formula, R1 and R2 may be the same or different, and each is a substituent containing a heteroatom, or each is hydrogen, a linear or branched alkyl having 1 to 10 carbon atoms, a linear or branched alkenyl having 2 to 10 carbon atoms, an aryl having 6 to 20 carbon atoms, an alkylaryl having 7 to 21 carbon atoms, an arylalkyl having 7 to 21 carbon atoms, a cycloalkyl having 3 to 10 carbon atoms, an alkoxy having 1 to 10 carbon atoms, an aryloxy having 6 to 20 carbon atoms, an alkylsilyl having 1 to 10 carbon atoms, an arylsilyl having 6 to 20 carbon atoms, or a halogen, and each n is independently a rational number of 0 to 20.

[0023] [ka]

[0024] In the formula, R1 and R2 may be the same or different, and each is a substituent containing a heteroatom, or each is hydrogen, a linear or branched alkyl having 1 to 10 carbon atoms, a linear or branched alkenyl having 2 to 10 carbon atoms, an aryl having 6 to 20 carbon atoms, an alkylaryl having 7 to 21 carbon atoms, an arylalkyl having 7 to 21 carbon atoms, a cycloalkyl having 3 to 10 carbon atoms, an alkoxy having 1 to 10 carbon atoms, an aryloxy having 6 to 20 carbon atoms, an alkylsilyl having 1 to 10 carbon atoms, an arylsilyl having 6 to 20 carbon atoms, or a halogen, and each n is independently a rational number of 0 to 20.

[0025] [ka]

[0026] In the formula, R1 and R2 may be the same or different, and each is a substituent containing a heteroatom, or each is hydrogen, a linear or branched alkyl having 1 to 10 carbon atoms, a linear or branched alkenyl having 2 to 10 carbon atoms, an aryl having 6 to 20 carbon atoms, an alkylaryl having 7 to 21 carbon atoms, an arylalkyl having 7 to 21 carbon atoms, a cycloalkyl having 3 to 10 carbon atoms, an alkoxy having 1 to 10 carbon atoms, an aryloxy having 6 to 20 carbon atoms, an alkylsilyl having 1 to 10 carbon atoms, an arylsilyl having 6 to 20 carbon atoms, or a halogen, and each n is independently a rational number of 0 to 10.

[0027] In a preferred embodiment of the present invention, the alkali metal may include at least one selected from the group consisting of metal hydride, metal hydroxide, and metal alkoxide, but is not limited thereto.

[0028] In a preferred embodiment of the present invention, the lactam may be preferably, but is not limited to, laurolactam, and may include caprolactam, piperidone, pyrrolidone, enantholactam, and capryllactam, and may optionally include propiolactam, 2-pyrrolidone, valerolactam, caprolactam, heptalactam, octanolactam, nonanolactam, decanolactam, undecanolactam, and dodecanolactam, and one or more of the above lactams.

[0029] In a preferred embodiment of the present invention, the activator may include at least one selected from the group consisting of carbon dioxide, benzoyl chloride, N-acetyl caprolactam, N-acetyl laurolactam, octadecyl isocyanate (SIC), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), and mixtures thereof.

[0030] In a preferred embodiment of the present invention, the polymerization reaction may be carried out within a range of 0.5 to 120 minutes based on a laboratory reactor. Here, the polymerization reaction time is not particularly limited, and may be appropriately adjusted according to the weight of the compound to be added or the size and type of the reactor.

[0031] In a preferred embodiment of the present invention, the lactam may be polymerized with a conversion of 95% or more in the polymerization reaction.

[0032] In a preferred embodiment of the present invention, the polymerization temperature is in the range of 180 to 300°C.

[0033] On the other hand, the present invention provides a polyamide produced by the above-mentioned production method.

[0034] In a preferred embodiment of the present invention, the polyamide may have a molecular weight distribution range of 3.0 or less.

[0035] In a preferred embodiment of the present invention, the weight average molecular weight (Mw) of the polyamide may be in the range of 20,000 to 100,000.

[0036] In a preferred embodiment of the present invention, the polyamide may be of linear, branched, hyperbranched or dendritic structure.

[0037] Meanwhile, the present invention provides a part material selected from the group consisting of vehicle materials, electronic device materials, industrial pipe materials, construction and civil engineering materials, 3D printer materials, textile materials, clothing materials, machine tool materials, medical materials, aviation materials, solar power materials, battery materials, sports materials, home appliance materials, household materials, and cosmetic materials, which is manufactured using the polyamide.

[0038] Specific examples of products including the above-mentioned component materials include, but are not limited to, vehicle air ducts, plastic / rubber compounds, adhesives, lights, polymer optical fibers, fuel filter caps, line systems, electronic device cables, reflectors, cable sheaths, optical fibers, electrical conduits, control units, lights, pipe tubes, liners, pipe coatings, oil field exploration hoses, 3D printers, multifilaments, spray hoses, valves, ducts, pulp, gears, medical catheters, aircraft flame retardants, solar cell protection panels, cosmetics, high-hardness films, ski boots, headsets, eyeglass frames, toothbrushes, water pitchers, and outsoles. Effect of the Invention

[0039] As described above, the present invention can easily control the molecular weight of polyamide and produce a polyamide having a narrow molecular weight distribution, so that an increase in molecular weight due to a basic intermediate produced in anionic polymerization and a side reaction occurring under high temperature polymerization conditions can be prevented.

[0040] In addition, the present invention is an environmentally friendly process that does not use a solvent as a catalyst, and has the effect of enabling polymer polymerization with a uniform molecular weight at a high conversion rate within a short polymerization reaction time at a low temperature compared to conventional polymerization methods.

[0041] In addition, the present invention has the advantage that the polymerization time is short, bulk polymerization is possible, and the productivity is greatly improved through a continuous process, thereby greatly reducing the efficiency of the production process and the production cost. [Brief description of the drawings]

[0042] [Figure 1] 1 is a graph showing the results of a Rheometer analysis of a polymer sample prepared according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] The following description of the present invention refers to, by way of example, specific embodiments in which the present invention may be practiced. These embodiments are described in detail to enable those skilled in the art to fully practice the present invention. It should be understood that the various embodiments of the present invention are different from one another but are not necessarily mutually exclusive. For example, a particular shape, structure, and characteristic described herein in connection with one embodiment may be embodied in other embodiments without departing from the spirit and scope of the present invention.

[0044] Accordingly, the following detailed description is not intended to be taken in a limiting sense, and the scope of the present invention is limited only by the appended claims, along with the full scope of equivalents that such claims are entitled to when properly written.

[0045] In addition, unless otherwise specified in the present specification, "substituted" or "substituted" means that one or more hydrogen atoms of the functional group of the present invention are substituted with one or more substituents selected from the group consisting of a halogen atom (-F, -Cl, -Br or -I), a hydroxyl group, a nitro group, a cyano group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxyl group, an ester group, a ketone group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alicyclic organic group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted heteroaryl group, and a substituted or unsubstituted heterocyclic group, and the above substituents may be bonded to each other to form a ring.

[0046] In the present invention, unless otherwise specified, the term "substituted" means that a hydrogen atom is substituted with a substituent such as a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryloxy group having 6 to 20 carbon atoms.

[0047] Furthermore, unless otherwise specified, the term "hydrocarbon group" refers to a linear, branched or cyclic saturated or unsaturated hydrocarbon group, and the alkyl group, alkenyl group, alkynyl group, etc. may be linear, branched or cyclic.

[0048] In addition, unless otherwise specified in the present specification, an "alkyl group" refers to a C1 to C30 alkyl group, and an "aryl group" refers to a C6 to C30 aryl group. In the present specification, a "heterocyclic group" refers to a group containing 1 to 3 heteroatoms selected from the group consisting of O, S, N, P, Si and combinations thereof in one ring, such as, but not limited to, pyridine, thiophene, pyrazine, etc.

[0049] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail in order to enable those skilled in the art to easily practice the present invention.

[0050] As described above, conventional anionic polymerization has limitations in solving the high viscosity phenomenon of polymers caused by the increase in molecular weight due to side reactions such as branching and cross-linking, which occur under high temperature polymerization conditions, and basic intermediates generated in anionic polymerization.

[0051] Therefore, the present invention provides a method for producing a polyamide containing an amide-based molecular weight regulator by an anionic polymerization reaction, comprising the steps of: The present invention provides a method for producing polyamides comprising the steps of: lactam; 0.01 to 20 parts by weight of an alkali metal as an initiator, 0.3 to 10 parts by weight of an amide-based compound represented by the following formula 1 as a molecular weight regulator, and 0.002 to 7.0 parts by weight of carbon dioxide as an activator, based on 100 parts by weight of the total lactam; and a method for producing polyamides comprising the steps of:

[0052] [ka]

[0053] In the formula, R1 and R2 may be the same or different, and each is a substituent containing a heteroatom, or each is hydrogen, a linear or branched alkyl having 1 to 10 carbon atoms, a linear or branched alkenyl having 2 to 10 carbon atoms, an aryl having 6 to 20 carbon atoms, an alkylaryl having 7 to 21 carbon atoms, an arylalkyl having 7 to 21 carbon atoms, a cycloalkyl having 3 to 10 carbon atoms, an alkoxy having 1 to 10 carbon atoms, an aryloxy having 6 to 20 carbon atoms, an alkylsilyl having 1 to 10 carbon atoms, an arylsilyl having 6 to 20 carbon atoms, or a halogen, and each n is independently a rational number of 0 to 20.

[0054] According to the present invention, the molecular weight regulator represented by the above Chemical Formula 1 can be prepared by the following Reaction Scheme 1.

[0055] [ka]

[0056] In addition, according to the present invention, the molecular weight regulator may include a urea-based compound represented by the following Chemical Formula 2.

[0057] [ka]

[0058] In the formula, R1 and R2 may be the same or different, and each is a substituent containing a heteroatom, or each is hydrogen, a linear or branched alkyl having 1 to 10 carbon atoms, a linear or branched alkenyl having 2 to 10 carbon atoms, an aryl having 6 to 20 carbon atoms, an alkylaryl having 7 to 21 carbon atoms, an arylalkyl having 7 to 21 carbon atoms, a cycloalkyl having 3 to 10 carbon atoms, an alkoxy having 1 to 10 carbon atoms, an aryloxy having 6 to 20 carbon atoms, an alkylsilyl having 1 to 10 carbon atoms, an arylsilyl having 6 to 20 carbon atoms, or a halogen, and each n is independently a rational number of 0 to 20.

[0059] According to the present invention, the molecular weight regulator represented by the above Chemical Formula 2 can be prepared by the following Reaction Scheme 2.

[0060] [ka]

[0061] In addition, according to the present invention, the molecular weight regulator may include a urea-based compound represented by the following Chemical Formula 3.

[0062] [ka]

[0063] In the formula, R1 and R2 may be the same or different, and each is a substituent containing a heteroatom, or each is hydrogen, a linear or branched alkyl having 1 to 10 carbon atoms, a linear or branched alkenyl having 2 to 10 carbon atoms, an aryl having 6 to 20 carbon atoms, an alkylaryl having 7 to 21 carbon atoms, an arylalkyl having 7 to 21 carbon atoms, a cycloalkyl having 3 to 10 carbon atoms, an alkoxy having 1 to 10 carbon atoms, an aryloxy having 6 to 20 carbon atoms, an alkylsilyl having 1 to 10 carbon atoms, an arylsilyl having 6 to 20 carbon atoms, or a halogen, and each n is independently a rational number of 0 to 20.

[0064] According to the present invention, the molecular weight regulator represented by the above formula 3 can be prepared by the following reaction formula 3.

[0065] [ka]

[0066] In addition, according to the present invention, the molecular weight regulator may include a urea-based compound represented by the following Chemical Formula 4.

[0067] [ka]

[0068] In the formula, R1 and R2 may be the same or different, and each is a substituent containing a heteroatom, or each is hydrogen, a linear or branched alkyl having 1 to 10 carbon atoms, a linear or branched alkenyl having 2 to 10 carbon atoms, an aryl having 6 to 20 carbon atoms, an alkylaryl having 7 to 21 carbon atoms, an arylalkyl having 7 to 21 carbon atoms, a cycloalkyl having 3 to 10 carbon atoms, an alkoxy having 1 to 10 carbon atoms, an aryloxy having 6 to 20 carbon atoms, an alkylsilyl having 1 to 10 carbon atoms, an arylsilyl having 6 to 20 carbon atoms, or a halogen, and each n is independently a rational number of 0 to 10.

[0069] According to the present invention, the molecular weight regulator represented by the above Chemical Formula 4 can be prepared by the following Reaction Scheme 4.

[0070] [ka]

[0071] Specifically, the composition used in the production of polyamides containing the amide-based molecular weight regulator according to the present invention will be described below.

[0072] First, the laurolactam according to the present invention can be preferably used as a monomer for preparing a polyamide, but is not limited thereto, and may include, for example, caprolactam, piperidone, pyrrolidone, enantholactam, and capryllactam, and may also include, in some cases, propiolactam, 2-pyrrolidone, valerolactam, caprolactam, heptalactam, octanolactam, nonanolactam, decanolactam, undecanolactam, and dodecanolactam.

[0073] The alkali metal catalyst according to the present invention is an initiator for producing a polyamide and may include at least one selected from the group consisting of metal hydrides, metal hydroxides, and metal alkoxides as a compound that allows the formation of the laurolactam anion.

[0074] In specific examples, the metal hydrides may include sodium hydride and potassium hydride, the metal hydroxides may include sodium hydroxide and potassium hydroxide, and the metal alkoxides may include, but are not limited to, potassium tert-butoxide and aluminum isopropoxide.

[0075] For example, the metal alkoxide may be sodium caprolactamate or potassium caprolactamate, an alkaline earth metal caprolactamate, such as magnesium bromide caprolactamate, magnesium chloride caprolactamate, or magnesium biscaprolactamate, an alkali metal, such as sodium or potassium, an alkali metal base, such as a sodium base, such as sodium hydride, sodium hydroxide, sodium methanolate, sodium ethanolate, sodium propanolate, or sodium butanolate, or for example a potassium base, such as potassium hydride, potassium hydroxide, potassium methanolate, potassium ethanolate. , potassium propaneolate, potassium butanolate, or mixtures thereof, preferably sodium caprolactamate, potassium caprolactamate, magnesium bromide caprolactamate, magnesium chloride caprolactamate, magnesium biscaprolactamate, sodium hydride, sodium, sodium hydroxide, sodium ethanolate, sodium methanolate, sodium propaneolate, sodium butanolate, potassium hydride, potassium, potassium hydroxide, potassium methanolate, potassium ethanolate, potassium propaneolate, potassium butanolate, or mixtures thereof. Also, the compound may include one or more selected from the group consisting of sodium hydride, sodium, and sodium caprolactamate, and mixtures thereof.

[0076] Such metal catalysts can be used in solid form or as a solution, and it is preferred to use the catalyst in solid form. The catalyst is preferably added to the laurolactam melt in which it can be dissolved. These catalysts provide a particularly fast reaction, which can increase the efficiency of the manufacturing process for the polyamides according to the invention.

[0077] According to the present invention, the alkali metal catalyst may be included in an amount of 0.01 to 20 parts by weight, preferably 0.03 to 10 parts by weight, and more preferably 0.05 to 5.0 parts by weight, based on 100 parts by weight of the total amount of laurolactam.

[0078] At this time, if the alkali metal catalyst is added in an amount less than 0.01 parts by weight, problems such as non-polymerization or a decrease in reaction rate may occur, whereas if the alkali metal catalyst is added in an amount more than 20 parts by weight, problems such as a decrease in molecular weight may occur. Therefore, the above range is preferable.

[0079] Next, the molecular weight regulator according to the present invention may preferably include at least one selected from the group consisting of the compounds of Formulas 1 to 4.

[0080] According to the present invention, the molecular weight modifier may be included in an amount of 0.3 to 10 parts by weight, preferably 0.4 to 0.7 parts by weight, more preferably 0.5 to 3.0 parts by weight, based on 100 parts by weight of the total amount of laurolactam.

[0081] At this time, if the molecular weight regulator is added in an amount less than 0.3 parts by weight, gelation (crosslinking, branching reaction) problems may occur, and if the molecular weight regulator is added in an amount more than 10 parts by weight, molecular weight reduction problems may occur, so the above ranges are preferable.

[0082] In relation to this, as shown in FIG. 1, the rheometer measurement results of the polymerization sample prepared as described above confirmed that the viscosity of the polymerization sample containing the molecular weight regulator decreased. Therefore, when the molecular weight regulator is contained within the above range, the molecular weight can be effectively controlled.

[0083] Finally, according to the present invention, the activator may be preferably carbon dioxide (CO), but is not limited thereto, and may include, for example, one or more selected from the group consisting of benzoyl chloride, N-acetyl caprolactam, N-acetyl laurolactam, octadecyl isocyanate (SIC), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), and mixtures thereof.

[0084] The carbon dioxide may be contained in an amount of 0.002 to 7.0 parts by weight, preferably 0.005 to 0.5 parts by weight, and more preferably 0.01 to 0.1 parts by weight, based on 100 parts by weight of the total amount of laurolactam.

[0085] At this time, if the carbon dioxide is added in an amount less than 0.002 parts by weight, problems of non-polymerization or a decrease in reaction rate may occur, and if the carbon dioxide is added in an amount more than 7.0 parts by weight, problems of gelation or depolymerization may occur, so the above ranges are preferable.

[0086] In the following, preferred examples are presented to aid in understanding the present invention. However, the following examples are merely intended to aid in understanding the present invention, and the present invention is not limited to the following experimental examples. EXAMPLES

[0087] [Example] <Example 1> Preparation of polymerization samples using acetanilide as a molecular weight regulator. In order to remove moisture from the flask, the flask was kept at 60°C under vacuum, and then the vacuum was released. 20g of laurolactam, 0.14g of acetanilide, and 0.02g of NaH were added and the temperature was raised to 160°C under vacuum. Then, the reaction temperature was set to 230°C, and hydrogen gas generated as the materials were melted was removed by introducing nitrogen gas, and 3.4ml of carbon dioxide was introduced and the reaction was carried out for 30 minutes. Finally, after 30 minutes, a formic acid solution (formic acid:distilled water=1:1) was added to the flask to terminate the reaction, and a sample having the content shown in Table 1 below was collected. The molecular weight and molecular weight distribution (PDI: polydispersity index) were determined using this, and the results are shown in Table 2.

[0088] [Table 1]

[0089] <Example 2> Preparation of polymerization samples using urea as a molecular weight regulator. The reaction was carried out in the same manner as in Example 1, except that 0.12 g of urea was used as a molecular weight regulator.

[0090] <Example 3> Preparation of polymerization samples using urea as a molecular weight regulator. The reaction was carried out in the same manner as in Example 1, except that 0.18 g of urea was used as a molecular weight regulator.

[0091] <Example 4> Preparation of polymerization samples using urea as a molecular weight regulator. The reaction was carried out in the same manner as in Example 1, except that 0.24 g of urea was used as a molecular weight regulator.

[0092] <Example 5> Preparation of polymerization samples using urea as a molecular weight regulator. The reaction was carried out in the same manner as in Example 1, except that 0.27 g of di-urea was used as a molecular weight regulator.

[0093] <Examples 6 to 11> Polymer samples were prepared in the same manner as in Example 1, except that the content ratios of the compositions were changed as shown in Table 1 above.

[0094] <Examples 12 to 13> Polymerization samples were prepared in the same manner as in Example 1, except that the polymerization conditions were set by varying the content ratio and type of the composition as shown in Table 2 below.

[0095] [Table 2]

[0096] [Comparative Example] <Comparative Example 1> The reaction was carried out in the same manner as in Example 1, except that no molecular weight regulator was added.

[0097] <Comparative Example 2> The reaction was carried out in the same manner as in Example 1, except that 0.15 g of EBS was used as the molecular weight regulator.

[0098] [Table 3]

[0099] As shown in Table 3, Comparative Example 1, in which no molecular weight regulator was added, showed a high molecular weight farther from the target molecular weight and a high molecular weight distribution compared to Example 1. However, Comparative Example 2, in which EBS was used as a molecular weight regulator, showed a relatively low molecular weight compared to Example 1, but the molecular weight distribution was within the target molecular weight distribution range.

[0100] The present invention has been described above with reference to the drawings according to an embodiment of the present invention. However, a person having ordinary knowledge in the field to which the present invention belongs can make various applications and modifications within the scope of the present invention based on the above content.

Claims

1. A method for producing a polyamide containing an amide-based molecular weight regulator by an anionic polymerization reaction, comprising the steps of: lactam, 0.01 to 20 parts by weight of an alkali metal initiator, a molecular weight regulator, and 0.002 to 7.0 parts by weight of an activator, based on 100 parts by weight of the lactam in total; The molecular weight regulator is acetanilide or urea, and the content of the molecular weight regulator when it is acetanilide is 0.25 to 4.5 parts by weight, and the content of the molecular weight regulator when it is urea is 0.9 to 1.35 parts by weight; the alkali metal is NaH; The activator is carbon dioxide.

1. A method for producing a polyamide comprising the step of:

2. The lactam is not limited to laurolactam, but may include caprolactam, piperidone, pyrrolidone, enantholactam, and capryllactam, and in some cases may include propiolactam, 2-pyrrolidone, valerolactam, caprolactam, heptanolactam, octanolactam, nonanolactam, decanolactam, undecanolactam, and dodecanolactam, and mixtures containing at least one of the above lactams.

2. The method for producing a polyamide by anionic ring-opening polymerization according to claim 1.

3. The polymerization reaction is carried out for 0.5 to 120 minutes. A method for producing a polyamide, comprising the amide-based molecular weight regulator according to claim 1 or 2.

4. The lactam has a conversion of 95% or more in the polymerization reaction. A method for producing a polyamide, comprising the amide-based molecular weight regulator according to claim 1 or 2.

5. The polymerization temperature of the polymerization reaction is in the range of 180 to 300° C. A method for producing a polyamide, comprising the amide-based molecular weight regulator according to claim 1.

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