METHOD FOR PREPARING POLYAMIDE BY ANION RING-OPENING POLYMERIZATION AND POLYAMIDE PREPARED THEREBY

Abstract

Provided is a method for preparing a polyamide 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, 0.3 parts by weight to 10 parts by weight of a molecular weight controller, and 0.002 parts by weight to 1.0 part by weight of carbon dioxide as an activator may be included.

Claims

1. A method for preparing a polyamide by an anionic polymerization reaction that is a method for preparing a polyamide by anionic ring-opening polymerization, 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, 0.3 parts by weight to 10 parts by weight of a molecular weight controller, and 0.002 parts by weight to 1.0 part by weight of carbon dioxide as an activator are included.

2. The method of claim 1, wherein the lactam comprises at least one selected from the group consisting of caprolactam, laurolactam, pyrrolidone, and piperidinone.

3. The method of claim 2, wherein the lactam comprises two types of lactams, and an amount of at least one of the lactams is 50 parts by weight or more based on 100 parts by weight of the entire lactams.

4. The method of claim 1, wherein the activator comprises at least one selected from the group consisting of benzoyl chloride, N-acetyl caprolactam, N-acetyl laurolactam, octadecyl isocyanate (SIC), toluene diisocyanate (TDI), and hexamethylene diisocyanate (HDI).

5. The method of claim 1, wherein the alkali metal comprises at least one selected from the group consisting of metal hydride, metal hydroxide, and metal alkoxide.

6. The method of claim 1, wherein the molecular weight controller comprises at least one selected from the group consisting of ethylene-bis-stearamide (EBS), an amine compound, a urea compound, and a di-urea compound.

7. The method of claim 1, wherein the polymerization reaction is performed within a range of 0.5 minutes to 120 minutes.

8. The method of claim 1, wherein the lactam in the polymerization reaction has a conversion rate of 95% or more to the polyamide.

9. The method of claim 1, wherein a polymerization temperature in the polymerization reaction is in a range of 180 C. to 300 C.

10. A polyamide prepared by the method of claim 1.

11. The polyamide of claim 10, wherein the polyamide has a polydispersity index (PDI) of 3.0 or less.

12. The polyamide of claim 10, wherein a weight average molecular weight (Mw) of the polyamide is in a range of 20,000 to 100,000.

13. The polyamide of claim 10, wherein the polyamide has a linear, branched, hyperbranched, or dendritic structure

14. 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 of claim 10.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0034] FIG. 1 is a graph showing a result of GPC analysis of a polymerization sample prepared according to the present invention.

[0035] FIG. 2 is a graph showing a result of DSC analysis of a polymerization sample prepared according to the present invention.

[0036] FIG. 3 is a graph showing a result of TGA analysis of a polymerization sample prepared according to the present invention.

BEST MODE

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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 C.sub.1-C.sub.20hydrocarbon group, a C.sub.1-C.sub.20alkoxy group, and a C.sub.6-C.sub.20aryloxy group.

[0041] In addition, unless otherwise specified, the term hydrocarbon group refers to a linear, branched, or cyclic saturated or unsaturated hydrocarbon group, and the alkyl group. The alkenyl group, the alkynyl group, and the like may be linear, branched, or cyclic.

[0042] In addition, unless otherwise specified in the present specification, the term alkyl group refers to a C.sub.1-C.sub.30alkyl group and the term aryl group refers to a C.sub.6-C.sub.30aryl 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.

[0043] 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.

[0044] As described above, there have been limitations in limiting the inefficiency of the processing, which is caused by the problems occurring in hydrolytic polymerization, catalytic ring-opening polymerization, and anionic ring-opening polymerization among the conventional polyamide polymerization methods, and the increase in viscosity due to side reactions at high temperature polymerization.

[0045] The present invention is an eco-friendly processing method using carbon dioxide (CO.sub.2) instead of a solvent as a catalyst and enables polymerization to a uniform molecular weight with a high conversion rate in a short polymerization reaction time at a low temperature, compared with an existing polymerization method, thereby providing the solution to the above-described problems.

[0046] A method for preparing a polyamide by an anionic polymerization reaction according to the present invention is a method for preparing a polyamide by anionic ring-opening polymerization, 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, 0.3 parts by weight to 10 parts by weight of a molecular weight controller, and 0.002 parts by weight to 1.0 part by weight of carbon dioxide as an activator are included.

[0047] Specifically, compositions included in the preparation of the polyamide by the anionic ring-opening polymerization according to the present invention will be described below.

[0048] The lactam according to the present invention may be preferably used as a monomer for preparing the polyamide. However, the present invention is not limited thereto. The lactam may contain 4 to 12 carbon atoms in the ring. For example, the lactam 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.

[0049] The lactam according to the present invention may include at least one selected from the group consisting of caprolactam, laurolactam, pyrrolidone, and piperidinone. For example, a mixture of caprolactam and laurolactam may be used, but the present invention is not limited thereto.

[0050] The lactam may include two types of lactams. An amount of at least one of the lactams may be 50 parts by weight or more based on 100 parts by weight of the entire lactams.

[0051] For example, the lactam may include two types of lactams. The two types of lactams may be caprolactam and laurolactam. An amount of one of the lactams may be 50 parts by weight or more. For example, the lactam may include 90 parts by weight of caprolactam and 10 parts by weight of laurolactam. However, this is only an example, and the present invention is not limited thereto.

[0052] 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 lactam anion.

[0053] 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 tetra-butoxide and aluminum isopropoxide, but the present invention is not limited thereto.

[0054] 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.

[0055] 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 laurolactam melt in which the catalyst can be dissolved. These catalysts lead to particularly rapid reactions, thereby increasing the efficiency of the process for preparing the polyamide according to the invention.

[0056] 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 0.03 parts by weight to 10 parts by weight, and more preferably 0.05 parts by weight to 5.0 parts by weight.

[0057] 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 low-molecular-weight polymer may be generated. Therefore, the above range is preferable.

[0058] Next, the molecular weight controller according to the present invention may be preferably 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.

[0059] According to the present invention, an amount of the molecular weight controller may be in a range of 0.3 parts by weight to 10 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 0.4 parts by weight to 7.0 parts by weight, and more preferably 0.5 parts by weight to 3.0 parts by weight.

[0060] In this case, when the molecular weight controller is added in an amount of less than 0.3 parts by weight, a high-molecular-weight polymer may be generated or a gelation problem may occur. When the amount of the molecular weight controller exceeds 10 parts by weight, a low-molecular-weight polymer may be generated or unpolymerization may occur. Therefore, the above range is preferable.

[0061] Finally, according to the invention, the activator may preferably be carbon dioxide (CO.sub.2), 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), and hexamethylene diisocyanate (HDI).

[0062] According to the present invention, 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 5 parts by weight, and more preferably 0.01 parts by weight to 0.1 parts by weight.

[0063] 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 problem may occur. Therefore, the above range is preferable.

[0064] 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.

EXAMPLES

Example 1

[0065] Preparation of polymerization samples using carbon dioxide (CO.sub.2) as activator

[0066] In order to remove moisture from a flask, a vacuum was released from the flask that was maintained at 60 C. in a vacuum state. 20 g of laurolactam, 0.15 g of EBS, and 0.02 g of NaH were added to the flask and the temperature was raised to 160 C. under vacuum. Then, the reaction temperature was set to 230 C. and nitrogen gas was added thereto. Hydrogen gas generated while the materials were molten was removed. 1.7 ml of carbon dioxide was injected and reacted for 30 minutes. Finally, after 30 minutes, an aqueous formic acid solution (formic acid:distilled water=1:1) was added to the flask to terminate the reaction. Samples having contents shown in Table 1 were collected. Using this, a molecular weight and a polydispersity index (PDI) were confirmed and the results thereof are shown in Table 2 below.

TABLE-US-00001 TABLE 1 Alkali Molecular Amount metal weight of CO.sub.2 Lactam (g) (g) controller (g) (ml) Example 1 Laurolactam 20 0.02 0.15 1.7 Example 2 Laurolactam 20 0.04 0.30 3.4 Example 3 Laurolactam 20 0.002 0.15 1.7 Example 4 Laurolactam 20 0.05 0.15 1.7 Example 5 Laurolactam 20 0.09 0.15 1.7 Example 6 Laurolactam 20 0.02 0.05 1.7 Example 7 Laurolactam 20 0.02 0.6 1.7 Example 8 Laurolactam 20 0.02 0.9 1.7 Example 9 Laurolactam 20 0.02 0.15 0.2 Example 10 Laurolactam 20 0.02 0.15 6 Example 11 Laurolactam 20 0.02 0.15 100 Example 12 Laurolactam 2 0.04 0.30 3.4 Caprolactam 18 Comparative 20 0.02 1.7 Example 1 Comparative 20 0.02 0.15 Example 2 Comparative 20 0.15 1.7 Example 3

Example 2

[0067] Preparation of polymerization samples using carbon dioxide (CO.sub.2) as activator

[0068] A polymerization sample was prepared in the same manner as in Example 1, except that 0.30 g of EBS and 0.04 g of NaH were added.

Examples 3 to 11

[0069] Polymerization samples were prepared in the same manner as in Example 1, except that the content ratios of the compositions were different as shown in Table 1.

Example 12

[0070] A polymerization sample was prepared in the same manner as in Example 2, except that 2 g of laurolactam and 18 g of caprolactam were added as the monomer.

Comparative Examples

Comparative Example 1

[0071] A polymerization sample was prepared in the same manner as in Example 1, except that EBS was not used.

Comparative Example 2

[0072] A polymerization sample was prepared in the same manner as in Example 1, except that the reaction was performed for 30 minutes without injecting carbon dioxide.

Comparative Example 3

[0073] A polymerization sample was prepared in the same manner as in Example 1, except that NaH was added.

TABLE-US-00002 TABLE 2 Molecular Polydispersity weight index (g/mol) (PDI) Polymerization Example 1 73,500 2.5 Polymerization Example 2 53,900 2.5 Polymerization Example 3 Unpolymerization Example 4 43.000 Polymerization Example 5 20,000 Polymerization Example 6 >160,000 Gelation Example 7 18,000 Polymerization Example 8 12,000 Polymerization Example 9 Unpolymerization Example 10 85,000 2.5 Polymerization Example 11 >160,000 Gelation Example 12 48,000 2.5 Polymerization Comparative >160,000 6.5 Gelation Example 1 Comparative Unpolymerization Example 2 Comparative Unpolymerization Example 3

[0074] As shown in Table 2, Example 5 in which 0.09 g of NaH was included with respect to the laurolactam had a slightly lower molecular weight, compared with Examples 1 to 4. Example 8 in which 0.9 g of EBS was included with respect to the laurolactam had a lower molecular weight, compared with Examples 6 and 7, and Example 11 in which 12 ml of carbon dioxide (CO.sub.2) was included with respect to the laurolactam had a higher molecular weight, compared with Examples 9 and 10.

[0075] In addition, in the case of Comparative Example 1 that did not include EBS as the molecular weight controller, a very wide PDI was shown, compared with Examples 1 to 11. In the case of Comparative Example 3 that did not include NaH as the alkali metal or Comparative Example 2 that did not include carbon dioxide as the activator, polymerization was not performed.

[0076] Finally, in the case of Example 12, even when the mixture of laurolactam and caprolactam was used as the monomer, it was confirmed that polymerization was performed at a level at which the molecular weight and the PDI were good.

[0077] As shown in FIG. 1, GPC analysis of the polymerization sample prepared as described above showed that the weight average molecular weight (Mw) was 73,500 and the PDI was 2.5.

[0078] Furthermore, as shown in FIGS. 2 to 3, DSC analysis of the polymerization sample showed that the Tm value was 179 C., the oligomer remaining after polymerization was 5.1%, and the polymerization conversion rate was approximately 95%.

[0079] 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.