Patent Application
20210002424
The present invention relates to a method for preparing a polyamide by using a molecular weight controller (molecular weight control agent) having a double active group and a polyamide prepared thereby, and more particularly, to a method for preparing a polyamide by using a molecular weight controller having a double active group in anionic ring-opening copolymerization of a polyamide, thereby enabling molecular weight to be controlled through the addition reaction of the molecular weight controller, and a polyamide prepared thereby.
A polyamide resin is a linear polymer bonded by an amide (—NHCO—) bond. The polyamide resin is strong, has excellent physical properties in terms of friction resistance, abrasion resistance, oil resistance, and solvent resistance, and is easily melt-molded. Therefore, the polyamide resin is widely used as clothing materials, fibers for industrial materials, engineering plastics, and the like. Polyamides may be classified into aliphatic polyamides, aromatic polyamides, and aliphatic cyclic polyamides according to molecular structures. The aliphatic polyamides may be collectively referred to as nylon, and the aromatic polyamides may be collectively referred to as aramid.
Polyamides are prepared by various polymerization methods and may be classified into those prepared by ring-opening polymerization of lactam, such as nylon 6, those prepared by polycondensation of diamines and dibasic acids, such as nylon 6,6, nylon 6,10 and nylon 4,6, and those prepared by polycondensation of aminocarboxylic acids, such as nylon 11 and nylon 12. Furthermore, so-called hybrid polymerized nylons, such as hybrid condensates of caprolactam and 6,10-nylon salts (hexamethylenediamine and sebacate), are industrially produced, and various polyamides including functional groups such as side chains and hydroxyl groups, aromatic rings and, hetero rings in molecules have been studied.
Lactams, for example, caprolactam may be anionically polymerized. This method generally uses a catalyst and an initiator (also referred to as an activator) (activated anionic polymerization). Initiators or activators frequently used till now include diisocyanates or derivatives thereof.
U.S. Pat. No. 4,754,000 (Bayer AG) discloses activated anionic polymerization of lactams, which prepares polyamides using biuret-group-containing polyisocyanates derived from non-aromatic diisocyanates as an activator.
EP 1091991 (BASF AG) discloses a composition including polyisocyanurates having more than 3.5 NCO functional groups on average as a component A and a method for preparing a surface coating composition using the composition.
In U.S. Pat. No. 3,423,372, uncapped polyisocyanates are used (resulting in a significant reduction in reactivity), and an activator concentration in that example is very low ( 1/200 mol to 1/50 mol). Therefore, the polymerization time is significantly delayed.
In EP 0156129, a rubber (i.e., elastomer) is used as a precursor of a multifunctional activator. Therefore, the resulting PA is up to 1.12 GPa and is not rigid. The activator has a high weight average molecular weight (Mw). In this case, a large amount of activator is required (20% or more). A mixture of a bifunctional activator and a multifunctional activator is used. Therefore, the resulting polyamide is not a crosslinked material.
In addition, U.S. Pat. No. 4,067,861 (1978) discloses a technology for anionic polymerization of lactams through an extruder. A metering pump is installed between an extruder body and an extruder die so as to obtain a constant output and uniform viscosity and physical properties. Although attempting to mechanically solve viscosity non-uniformity, this is not a fundamental solution.
U.S. Pat. No. 3,878,173 (1975) points out the problem of unstable viscosity due to thermal decomposition and the formation of a structurally disorderly branching structure. However, in order to prevent decomposition of a synthesized polymer, an attempt to solve the problem is made just by using a more acidic additive. This US patent does not disclose the solution to the non-uniform branching structure. For reference, a branching side reaction that occurs during polyamide anion polymerization is discussed in detail in M. P. Stevens, “Polymer Chemistry”, 2nd Ed., Oxford University Press, p 429 (1990) and G. Odian, “Principles of Polymerization”, 2nd Ed., John Wiley & Sons, p 541 (1981).
In U.S. Pat. No. 5,747,634 (1998), a solution liquid system containing a catalyst and an initiator (reaction accelerator) at the same time is introduced so as to obtain a more uniform product. U.S. Pat. No. 5,747,634 discloses that the solution liquid system is introduced to obtain uniform products with a constant quality and a high reproducibility result, but there is a problem that is not efficient due to a problem of solvent removal when applying to a reaction extrusion method.
In particular, the conventional method has to depend on a method for inducing high molecular weight through additional side reactions. As in the case of polyamide 12 or polyamide 612, which is polymerized at a high temperature, the reaction is rapidly performed at a high polymerization temperature. Thus, there occurs a phenomenon in which the reaction occurs non-uniformly before a polymer chain is generated by sufficient reaction.
The present invention aims to solve the above-described problems of the related art and the technical problems requested from the past.
An object of the present invention is to provide a method for preparing a polyamide by using a molecular weight controller having a double active group in anionic ring-opening copolymerization of a polyamide, thereby enabling molecular weight to be controlled through the addition reaction of the molecular weight controller, and a polyamide prepared thereby.
In order to achieve the above objects, the present invention provides a method for preparing a polyamide using a molecular weight controller having a double active group.
The method is a method for preparing a polyamide which includes a molecular weight controller having a double active group by an anionic polymerization reaction, wherein
lactam, and based on 100 parts by weight of the entire lactam, 0.01 parts by weight to 20 parts by weight of an alkali metal as an initiator, 0.01 parts by weight to 5.0 parts by weight of a compound represented by Formula 2 as a molecular weight controller having a double active group, and a compound represented by Formula 1 using 0.01 parts by weight to 5.0 parts by weight of an activator are included:
wherein n and m are each independently a rational number satisfying n=m or n>m, and k is a rational number satisfying a condition that a weight average molecular weight (Mw) of the compound represented by Formula 1 is in a range of 20,000 g/mol to 100,000 g/mol,
In one preferred embodiment of the present invention, the lactam may include at least one selected from the group consisting of caprolactam, laurolactam, pyrrolidone, piperidinone, and any mixture thereof.
In one preferred embodiment of the present invention, two materials selected as the lactam may be included at a weight ratio of 20 to 80:80 to 20.
In one preferred embodiment of the present invention, the activator may include at least one selected from the group consisting of carbon dioxide (CO2), benzoyl chloride, N-acetyl caprolactam, N-acetyl laurolactam, octadecyl isocyanate (SIC), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), and any mixture thereof.
In one preferred embodiment of the present invention, the activator may be toluene diisocyanate (TDI).
In one preferred embodiment of the present invention, the molecular weight controller may have a melting temperature (Tm) of 160° C. to 180° C.
In one 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.
In one preferred embodiment of the present invention, the polymerization reaction may be performed in a range of 160° C. to 300° C. According to the present invention, the polymerization reaction may be performed in a range of 0.5 minutes to 120 minutes based on an experimental reactor. The polymerization reaction time is not particularly limited and may be appropriately adjusted according to a weight of a compound introduced or a size and a type of the reactor.
The present invention provides a polyamide prepared by the above-described method.
In one preferred embodiment of the present invention, the polyamide may have a polydispersity index (PDI) of 4 or less.
In one preferred embodiment of the present invention, a weight average molecular weight (Mw) of the polyamide may be in a range of 20,000 g/mol to 100,000 g/mol.
In one preferred embodiment of the present invention, the polyamide may have a linear, branched, hyperbranched, or dendritic structure.
In addition, the present invention provides a parts material selected from the group consisting of a vehicle material, an electronic device material, an industrial pipe material, a construction engineering material, a 3D printer material, a textile material, a cladding material, a machine tool material, a medical material, an aviation material, a photovoltaic material, a battery material, a sports material, a household appliance material, a household material, and a cosmetic material, which each include the polyamide.
In a specific example, a product including the parts material may be vehicle air ducts, plastic/rubber compounds, adhesives, lights, polymer optical fibers, fuel filter caps, line systems, cables for electronic devices, reflectors, sheaths of cables, optical fibers, wire protection tubes, control units, pipe tubes, liners, pipe coatings, oilfield exploration hoses, 3D printers, multifilaments, spray hoses, valves, ducts, pulps, gears, medical catheters, flame retardants for aircraft, solar cell protection plates, cosmetic materials, high hardness films, ski boots, headsets, glasses frames, toothbrushes, water bottles, or outsoles, but the present invention is not limited thereto.
As described above, since the molecular weight controller having the double active group is used in the anionic ring-opening copolymerization of the polyamide, the polyamide that enables molecular weight to be controlled through the addition reaction of the molecular weight controller can be prepared.
The present invention will be described with reference to specific embodiments and the accompanying drawings. The embodiments will be described in detail in such a manner that the present invention may be carried out by those of ordinary skill in the art. It should be understood that various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain shapes, structures, and features described herein may be implemented in other embodiments without departing from the spirit and scope of the present invention in connection with one embodiment.
Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims and the entire scope of equivalents thereof, if properly explained.
In addition, unless otherwise specified in the present specification, the term “substitution” or “substituted” means that one or more hydrogen atoms in the functional groups 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 hydroxy 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. These substituents may be linked to each other to form a ring.
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 C1-C20 hydrocarbon group, a C1-C20 alkoxy group, and a C6-C20 aryloxy group.
In addition, unless otherwise specified, the term “hydrocarbon group” refers to a linear, branched, or cyclic saturated or unsaturated hydrocarbon group. The alkyl group, the alkenyl group, the alkynyl group, and the like may be linear, branched, or cyclic.
In addition, unless otherwise specified in the present specification, the term “alkyl group” refers to a C1-C30 alkyl group and the term “aryl group” refers to a C6-C30 aryl group. In the present specification, the term “heterocyclic group” refers to a group in which one to three heteroatoms selected from the group consisting of O, S, N, P, Si, and any combination thereof are contained in one ring. Examples of the heterocyclic group may include pyridine, thiophene, and pyrazine, but the present invention is not limited thereto.
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, so that those of ordinary skill in the art can easily carry out the present invention.
As described above, since an activator used in a conventional anionic polymerization has only one carbonyl group that opens a cyclic structure in a molecular structure, there is a limitation in obtaining a polyamide having a high molecular weight.
The present invention seeks a solution to the above-described problems by providing a method for preparing a polyamide through anionic copolymerization using a molecular weight controller having a double active group in an anionic polymerization reaction.
Specifically, the present invention provides a method for preparing a polyamide, wherein a molecular weight controller by an anionic polymerization reaction is included.
Lactam, and based on 100 parts by weight of the entire lactam, 0.01 parts by weight to 20 parts by weight of an alkali metal as an initiator, 0.01 parts by weight to 5.0 parts by weight of a compound represented by Formula 2 as a molecular weight controller having a double active group, and a compound represented by Formula 1 using 0.01 parts by weight to 5.0 parts by weight of an activator may be included.
n and m are each independently a rational number satisfying n=m or n>m, and k is a rational number satisfying a condition that a weight average molecular weight (Mw) of the compound represented by Formula 1 is in a range of 20,000 g/mol to 100,000 g/mol.
More specifically, compositions included in the preparation of the polyamide, including the amide-based molecular weight controller according to the present invention, will be described below.
First, the lactam according to the present invention is a monomer for preparing a polyamide. Laurolactam may be preferably used as the monomer. However, the present invention is not limited thereto. For example, the lactam having 4 to 12 carbon atoms may include caprolactam, piperidone, pyrrolidone, enantolactam, and caprylactam. In some cases, the lactam may include propiolactam, 2-pyrrolidone, valerolactam, caprolactam, heptanolactam, octanolactam, nonanolactam, decanolactam, undecanolactam, and dodecanolactam.
In addition, the alkali metal catalyst according to the present invention is an initiator for preparing the polyamide and may include at least one selected from the group consisting of metal hydride, metal hydroxide, and metal alkoxide as a compound that allows the formation of the laurolactam anion.
In a specific example, the metal hydride may include sodium hydride and potassium hydride, the metal hydroxide may include sodium hydroxide and potassium hydroxide, and the metal alkoxide may include potassium tert-butoxide and aluminum isopropoxide, but the present invention is not limited thereto.
The metal alkoxide may include sodium caprolactamate or potassium caprolactamate, alkaline earth metal caprolactamate, for example, magnesium bromide caprolactamate, magnesium chloride caprolactamate, or magnesium biscaprolactamate, an alkali metal, for example, sodium or potassium, alkali metal base, for example, sodium base, for example sodium hydride, sodium, sodium hydroxide, sodium methanolate, sodium ethanolate, sodium propanolate, or sodium butanolate, or at least one selected from the group consisting of potassium base, for example potassium hydride, potassium, potassium hydroxide, potassium methanolate, potassium ethanolate, potassium propanolate, potassium butanolate, or any mixture thereof, and preferably at least one selected from the group consisting of sodium caprolactate, potassium caprolactate, magnesium bromide caprolactate, magnesium chloride caprolactate, magnesium biscaprolactate, sodium hydride, sodium, sodium hydroxide, sodium ethanolate, sodium methanolate, sodium propanolate, sodium butanolate, potassium hydride, potassium, potassium hydroxide, potassium methanolate, potassium ethanolate, potassium propanolate, potassium butanolate, and any mixture thereof. In addition, at least one selected from the group consisting of sodium hydride, sodium, sodium caprolactamate, and any mixture thereof may be included.
The metal catalyst may be used in the form of a solid or a solution, and the catalyst is preferably used in the form of a solid. The catalyst is preferably added to a lactam melt in which the catalyst can be dissolved. These catalysts lead to particularly rapid reactions, thereby increasing the efficiency of the process of preparing the polyamide according to the present invention.
According to the present invention, an amount of the alkali metal catalyst may be in a range of 0.01 parts by weight to 20 parts by weight based on 100 parts by weight of the entire lactam. The amount of the alkali metal catalyst may be in a range of preferably 0.1 parts by weight to 10 parts by weight, and more preferably 0.5 parts by weight to 5 parts by weight.
In this case, when the alkali metal catalyst is added in an amount of less than 0.01 parts by weight, unpolymerization may occur or a reaction rate may decrease. When the amount of the alkali metal catalyst exceeds 20 parts by weight, a molecular weight reduction problem may occur. Therefore, the above range is preferable.
Next, preferably, the molecular weight controller according to the present invention has the double active group including a compound represented by Formula 2.
In some cases, the molecular weight controller according to the present invention may be ethylene-bis-stearamide (EBS), but the present invention is not limited thereto. The molecular weight controller may include at least one selected from the group consisting of an amine compound, a urea compound, and a di-urea compound.
According to the present invention, an amount of the molecular weight controller may be in a range of 0.01 parts by weight to 5 parts by weight based on 100 parts by weight of the entire lactam. The amount of the molecular weight controller may be in a range of preferably 0.01 parts by weight to 2 parts by weight, and more preferably 0.01 parts by weight to 1 part by weight.
In this case, when the molecular weight controller is added in an amount of less than 0.01 parts by weight, a gelation (crosslinking or branching reaction) problem may occur. When the amount of the molecular weight controller exceeds 5 parts by weight, a molecular weight reduction problem may occur. Therefore, the above range is preferable.
In this regard, as shown in
Finally, the activator is not particularly limited.
For example, the activator is selected from the group consisting of lactam that is N-substituted by electrophilic moiety, aliphatic diisocyanate, aromatic diisocyanate, polyisocyanate having more than two isocyanate groups, aliphatic diacylhalide, and aromatic diacyl halide. In addition, the activator (C) may include at least one selected from the group consisting of mixtures of the above-described materials.
Specifically, according to the present invention, the activator may preferably include carbon dioxide (CO2), but the present invention is not limited thereto. For example, the activator may include at least one selected from the group consisting of benzoyl chloride, N-acetyl caprolactam, N-acetyl laurolactam, octadecyl isocyanate (SIC), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), and any mixture thereof.
An amount of the carbon dioxide may be in a range of 0.002 parts by weight to 1.0 part by weight based on 100 parts by weight of the entire lactam. The amount of the carbon dioxide may be in a range of preferably 0.005 parts by weight to 0.5 parts by weight, and more preferably 0.01 parts by weight to 0.1 parts by weight.
In this case, when the carbon dioxide is added in an amount of less than 0.002 parts by weight, unpolymerization may occur or a reaction rate may decrease. When the amount of the carbon dioxide exceeds 1.0 part by weight, a gelation or depolymerization problem may occur. Therefore, the above range is preferable.
Hereinafter, preferred examples are presented so as to help the understanding of the present invention. However, the following examples are for illustrative purposes only and the present invention is not limited by the following examples.
A stirrer, a reflux condenser tube, and a dropping funnel were installed in a 3-neck flask. At this time, all glass wares were previously dried in a nitrogen atmosphere, considering moisture-sensitive reactants. 1 mol eq. (197.32 g) of laurolactam as a monomer, 1 mol of triethylamine, and 500 ml of THF were added to the flask and then stirred. Triethylamine acts as a scavenger that removes hydrochloric acid produced when laurolactam and isophthaloyl chloride react with each other. The prepared mixture was stirred and cooled with ice, and a solution in which 0.5 mol eq. of isophthaloyl chloride was dissolved in 150 ml of THF was slowly added dropwise for 40 minutes. After the addition was completed, the reaction mixture was stirred at room temperature for 30 minutes and then filtered. A white solid product was dried in air and then stirred in 200 ml of water to remove a reaction by-product Et3NH+Cl−. The resultant product was washed twice with 100 ml distilled water on a filter paper. A white powder was dried in a vacuum oven at 80° C. and a material was identified by using DSC and 13C-NMR.
Caprolactam and laurolactam as a monomer and NaH as an initiator were weighed to a molar ratio of 50:50:1 and added to a 3-neck flask. A temperature of an oil bath was set to 160° C., and the monomer and the initiator were primarily dissolved in a nitrogen atmosphere. After confirming that the reactants were all melted, a vacuum was applied to remove hydrogen gas generated in the reactions. After the temperature was set to 230° C. at which the polymerization reaction actually occurred, 0.05 mol of the molecular weight controller and 0.15 mol of the activator (TDI) based on 100 mol of the lactam were added. When the polymerization was completed, a 1:1 mixed solution of formic acid and water was added to terminate the reaction. The resultant product was washed several times with water and alcohol and finally dried in a vacuum oven. A sample having content shown in Table 1 was collected. A relative viscosity of each sample was confirmed and the result thereof is shown in Table 2. At this time, a 2 wt % solution was prepared by adding a polymer to 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and the relative viscosity was measured at 25° C.
A polyamide was prepared in the same manner as in Example 1, except that an end-capping agent having a molar ratio of 0.2 was added.
A polyamide was prepared in the same manner as in Example 1, except that CO2 instead of TDI was added as an activator.
A molecular weight controller was prepared by using isophthaloyl-bis-caprolactam instead of isophthaloyl-bis-laurolactam, toluene instead of THF, and caprolactam instead of laurolactam. A polyamide was prepared in the same manner as in Example 1 by using the molecular weight controller.
A polymerization sample was prepared in the same manner as in Example 1, except that isophthaloyl-bis-laurolactam was not added.
As shown in Table 2, Comparative Examples 1 and 2 showed gelation because the molecular weight was not adjusted, as compared with Examples 1 to 3.
Although the present invention has been described with reference to the drawings according to embodiments of the present invention, it will be understood by those of ordinary skill in the art that various applications and modifications can be made thereto without departing from the scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2017-0160752 | Nov 2017 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2018/012909 | 10/29/2018 | WO | 00 |
