KR20220130439A - Polyamide resin and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a polyamide resin and a preparation method thereof, and more specifically, to a polyamide resin which improves molecular weight and mechanical properties by additionally making a prepolymer reaction with a molecular weight modifier after preparing the prepolymer by ring-opening polymerization of lactone.

Description

Polyamide resin and its manufacturing method

The present invention relates to a polyamide resin and a method for producing the same, and more particularly, to a polyamide resin that improves molecular weight and improves mechanical properties by reacting with a molecular weight modifier after preparing a prepolymer by ring-opening polymerization of lactone, and a method for producing the same it's about

Polyamide is an engineering polymer that is widely used in films, fibers, and packaging materials because of its excellent processability and excellent physical properties such as chemical resistance, ductility, toughness, and impact strength. is possible First, when prepared by condensation polymerization, a nylon salt (a mixture of diamine and dicarboxylic acid reacted 1:1) is reacted at high temperature and high pressure to make a low molecular weight polyamide pretreatment resin, and In order to increase the molecular weight, post-treatment condensation polymerization was performed by adjusting the amine and carboxyl groups in the same molar ratio. Matching the amine group and the carboxyl group of the same equivalent in the above-mentioned series of processes was an essential condition for obtaining a high molecular weight polyamide. Therefore, a process for removing unreacted reactants as well as removing water, a by-product generated in the pretreatment process, was required. Chains capable of reacting with various amines or carboxyl groups in order to increase the molecular weight and improve physical properties of low molecular weight polyamides Extenders have been used. Chain extenders capable of reacting with amine groups include bisoxazolinones and caprolactams, and chain extenders capable of reacting with carboxyl groups include cyclic carboxylic anhydride), bisoxazines, and bisoxazolines, and two or more may be used at the same time.

As described above, the method used so far to obtain polyamide 6 having a high molecular weight is polymerization of polyamide 6 in a condensation polymerization method, and reaction with a chain extender capable of reacting with amine or carboxyl group of the polymerized polyamide 6 polymer chain. that was the way to do it. However, this method has a disadvantage in that the required time and cost are very large since it has to go through several steps during polymerization and reforming. In the examples reported so far, since the process for the polymerization of polyamide and the process for increasing the molecular weight are separated, an additional process for increasing the molecular weight is required along with several processes to obtain polyamide, so the time to obtain the final product and the cost was high.

On the other hand, when polyamide is prepared by ring-opening polymerization of the monomer ε-caprolactam, the by-products are small and the polymerization of polyamide 6 is possible in one process, but since polymerization is performed through an anionic polymerization mechanism, the activated state of anions is reduced. Careful process control is required to maintain the polyamide 6 polymerized by ring-opening polymerization, and the polymer chain end group is caprolactamate. there was In addition, although the process can be reduced when the polyamide is polymerized by the ring-opening polymerization method, there was no example of using a chain extender compound capable of reacting with a caprolactamate reactive group as a chain extender to increase molecular weight. However, recently, the present inventors have increased the molecular weight of the polymerized polyamide and improved physical properties by adding a diamine or diepoxy compound capable of reacting with a caprolactamate reactive group to generate a new side branch structure. However, in these processes, the diepoxy compound and diamine are mixed with other reactants (monomer, initiator, activator) from the beginning during reaction processing and injected into the hopper, so that it is difficult to maintain a high activation state of the anion during anionic polymerization. It was restricted in molecular weight increase and physical properties increase.

In order to solve this problem, the diamine or diepoxy compound added for structural change during ring-opening polymerization of polyamide is added after the molecular weight of the polyamide has been polymerized to some extent to further increase the molecular weight of the polyamide and further increase the side chain structure. A process has been developed for easily generating and thus increasing the physical properties of the synthesized polyamide.

The technical problem to be achieved by the present invention is lactam; initiator; and a reaction activator; a polyamide resin capable of improving the molecular weight and physical properties of the polyamide while preventing a decrease in the activation state of anions used in the ring-opening polymerization process by adding a molecular weight modifier to the reaction after preparing a polymer of To provide a manufacturing method thereof.

In addition, in the polyamide resin production process through ring-opening polymerization in the extruder, the prepolymer is polymerized in the first half of the reaction furnace of the extruder, and then a molecular weight regulator is added to the second hopper to easily form a side chain structure of the polyamide. It is to provide a polyamide resin and a method for producing the same, thereby improving the molecular weight and physical properties of the polyamide resin and increasing process efficiency.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

One embodiment of the present invention is a lactam; initiator; and a reaction activator; and a prepolymer that is a polymer of a first mixture, and a polyamide resin that is a reaction product of a second mixture containing a molecular weight modifier.

An exemplary embodiment of the present invention provides a method for producing the polyamide resin, comprising the steps of: preparing a prepolymer by polymerizing the first mixture; and reacting the second mixture in which a molecular weight modifier is added to the prepolymer.

In the polyamide resin according to an exemplary embodiment of the present invention, in the process of polymerizing polyamide from a cyclic monomer, a caprolactamate reactive group, which is an end group of a polyamide resin chain, and a molecular weight regulator react with each other to maintain anion activity and have a side branch structure. can be produced to increase molecular weight and improve physical properties.

In addition, in the polyamide resin according to an exemplary embodiment of the present invention, by introducing a repeating unit of a diepoxy compound or a repeating unit of a diamine compound in the chain, the melt viscosity increases, and mechanical properties such as elastic modulus, tensile strength, elongation, toughness, etc. The physical properties can be improved.

The method for producing a polyamide resin according to an exemplary embodiment of the present invention can easily produce a polyamide resin having an improved molecular weight in a single process without using a solvent and improve process efficiency.

Effects of the present invention are not limited to the above-described effects, and effects not mentioned will be clearly understood by those skilled in the art from the present specification and accompanying drawings.

1 is a schematic diagram of an extruder according to an embodiment of the present invention.
2 is a graph showing wide-angle X-ray diffraction spectra of Comparative Example 1 and Examples 1 to 5;
Figure 3 (a) is a graph showing the viscosity rheological properties of the nylon 6 resin of Comparative Example 1 and Examples 1 to 5 measured by a rotation rheology measuring instrument.
Figure 3 (b) is a graph showing the viscosity rheological properties of the nylon 6 resin of Comparative Example 1 and Examples 6 to 10 measured by a rotation rheology measuring instrument.
Figure 4 (a) is a graph showing the measurement of the storage modulus (Storage modulus) of Comparative Example 1 and Examples 1 to 5 nylon 6 resin.
4 (b) is a graph showing the measurement of the loss modulus (Loss modulus) of the nylon 6 resin of Comparative Example 1 and Examples 1 to 5.
Figure 4 (c) is a graph showing the measurement of the storage modulus (Storage modulus) of Comparative Example 1 and Examples 6 to 10 nylon 6 resin.
4( d ) is a graph showing the measurement of the loss modulus of the nylon 6 resins of Comparative Example 1 and Examples 6 to 10 .
5 is a graph showing (a) elastic modulus, (b) tensile strength, (c) elongation, and (d) absorbed energy up to breakage of Comparative Example 1 and Examples 1 to 10. FIG.

Throughout this specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

Throughout this specification, the unit “part by mole” may mean a ratio of moles between each component.

Throughout this specification, the unit “part by weight” may mean a ratio of weight between each component.

Throughout this specification, "A and/or B" means "A and B, or A or B."

Throughout this specification, the term "monomer unit" may refer to a form in which a monomer is reacted in a polymer, and specifically, the monomer undergoes a polymerization reaction to form a backbone of the polymer, for example, a main chain or a side chain. It can mean the shape forming the .

Throughout this specification, the "weight average molecular weight" and "number average molecular weight" of a certain compound may be calculated using the molecular weight and molecular weight distribution of the compound. Specifically, put tetrahydrofuran (THF) and a compound in a 1 ml glass bottle to prepare a sample sample having a concentration of 1 wt% of the compound, and filter the standard sample (polystyrene, polystyrene) and the sample sample (pore size). After filtration through 0.45 μm), it is injected into a GPC injector, and the molecular weight and molecular weight distribution of the compound can be obtained by comparing the elution time of the sample sample with the calibration curve of the standard sample. In this case, an Infinity II 1260 (Agilient Co.) may be used as the measuring device, the flow rate may be 1.00 mL/min, and the column temperature may be set to 40.0 °C.

Throughout this specification, "Glass Temperature (Tg)" can be measured using Differential Scanning Analysis (DSC), specifically DSC (Differential Scanning Calorimeter, DSC-STAR3, METTLER TOLEDO) company), the sample is heated at a heating rate of 5 °C/min in a temperature range of -60 °C to 150 °C, and the DSC curve prepared at the point with the amount of thermal change by performing the experiment twice in the above section The glass transition temperature can be obtained by measuring the midpoint of

Throughout this specification, the viscosity of the compound may be a value measured with a Brookfield viscometer at a temperature of 25 °C.

Throughout the present specification, "substituted" means that at least one hydrogen atom is deuterium, C1 to C30 alkyl group, C3 to C30 cycloalkyl group, C2 to C30 heterocycloalkyl group, C1 to C30 halogenated alkyl group, C6 to C30 aryl group, C1 to C30 Heteroaryl group, C1 to C30 alkoxy group, C2 to C30 alkenyl group, C2 to C30 alkynyl group, C6 to C30 aryloxy group, silyloxy group (-OSiH ₃ ), -OsiR`H <sub>2</sub> (R` is C1 to C30 Alkyl group or C6 to C30 aryl group), -OsiR'R''H (R' and R'' are each independently a C1 to C30 alkyl group or C6 to C30 aryl group), -OsiR'R''R''', (R', R'', and R''' are each independently a C1 to C30 alkyl group or C6 to C30 aryl group), C1 to C30 acyl group, C2 to C30 acyloxy group, C2 to C30 heteroaryloxy group, C1 to C30 sulfonyl group, C1 to C30 alkylthiol group, C6 to C30 arylthiol group, C1 to C30 heterocyclothiol group, C1 to C30 phosphate amide group, silyl group (SiR'R''R'') (R ', R'', and R''' are each independently a hydrogen atom, a C1 to C30 alkyl group or a C6 to C30 aryl group), an amine group (-NR'R'') (wherein, R' and R'' are each independently a hydrogen atom, a substituent selected from the group consisting of a C1 to C30 alkyl group, and a C6 to C30 aryl group), a carboxyl group, a halogen group, a cyano group, a nitro group, an azo group, and a hydroxyl group It means substituted with a substituent.

Throughout this specification, two adjacent substituents among the above substituents may be fused to form a saturated or unsaturated ring.

Throughout this specification, the carbon number range of the alkyl group or aryl group in the "substituted or unsubstituted C1 to C30 alkyl group" or "substituted or unsubstituted C6 to C30 aryl group" etc. does not take into account the portion in which the substituent is substituted. It refers to the total number of carbon atoms constituting the alkyl part or the aryl part when viewed as unsubstituted. Specifically, the phenyl group substituted with a butyl group at the para position means that it corresponds to an aryl group having 6 carbon atoms substituted with a butyl group having 4 carbon atoms.

Throughout the present specification, the carbon number range of the fused aryl group in the "substituted or unsubstituted C6 to C30 fused aryl group" etc. is fused when viewed as unsubstituted without considering the substituted portion of the substituent. It means the total number of carbons constituting the newly formed aryl moiety.

Throughout this specification, unless otherwise defined, "hetero" means that one functional group contains 1 to 4 heteroatoms selected from the group consisting of N, O, S and P, and the remainder is carbon. .

Throughout the present specification, unless otherwise defined, the term "combination thereof" means that two or more substituents are bonded with a linking group, or that two or more substituents are condensed and bonded.

Throughout this specification, "hydrogen" means singlet, deuterium, or tritium, unless otherwise defined.

Throughout this specification, the term "alkyl group" refers to an aliphatic hydrocarbon group unless otherwise defined.

Throughout this specification, the alkyl group may be a "saturated alkyl group" that does not contain any double or triple bonds.

Throughout this specification, the alkyl group may be an "unsaturated alkyl group" containing at least one double bond or triple bond.

Throughout this specification, "alkenylene group" refers to a functional group in which at least two carbon atoms are composed of at least one carbon-carbon double bond, and "alkynylene group" refers to at least two carbon atoms having at least one refers to a functional group consisting of a carbon-carbon triple bond. Alkyl groups, whether saturated or unsaturated, can be branched, straight-chain or cyclic.

Throughout this specification, the alkyl group may be a C1 to C30 alkyl group. More specifically, it may be a C1 to C20 alkyl group, a C1 to C10 alkyl group, or a C1 to C6 alkyl group. Specifically, a C1 to C4 alkyl group has 1 to 4 carbon atoms in the alkyl chain, that is, the alkyl chain is composed of methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl and t-butyl. indicates selected from the group. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, a hexyl group, an ethenyl group, a propenyl group, a butenyl group, a cyclopropyl group, a cyclo It means a butyl group, a cyclopentyl group, a cyclohexyl group, etc.

Throughout this specification, "amine group" includes an amino group, an arylamine group, an alkylamine group, an arylalkylamine group, or an alkylarylamine group, and may be expressed as -NR'R'', where R' and R'' is each independently a substituent selected from the group consisting of a hydrogen atom, a C1 to C30 alkyl group, and a C6 to C30 aryl group.

Throughout this specification, "cycloalkyl group" includes monocyclic or fused-ring polycyclic (ie, rings having adjacent pairs of carbon atoms) functional groups.

Throughout the present specification, "heterocycloalkyl group" means that the cycloalkyl group contains 1 to 4 heteroatoms selected from the group consisting of N, O, S and P, and the remainder is carbon. When the heterocycloalkyl group is a fused ring, at least one ring of the fused ring may include 1 to 4 hetero atoms.

Throughout this specification, the term "aromatic group" refers to a functional group in which all elements of a ring-shaped functional group have p-orbitals, and these p-orbitals form a conjugate. Specific examples include an aryl group and a heteroaryl group.

Throughout this specification, "aryl group" includes monocyclic or fused ring polycyclic (ie, rings having adjacent pairs of carbon atoms) functional groups.

Throughout this specification, "heteroaryl group" means that it contains 1 to 4 heteroatoms selected from the group consisting of N, O, S and P in the aryl group, and the remainder is carbon. When the heteroaryl group is a fused ring, at least one ring of the fused ring may include 1 to 4 hetero atoms.

Throughout this specification, the number of atoms in the ring in the aryl group and the heteroaryl group is the sum of the number of carbon atoms and the number of non-carbon atoms.

Throughout this specification, when used in combination with "alkylaryl group" or "arylalkyl group", each of the terms alkyl and aryl have the meaning and content indicated above. Specifically, the term "arylalkyl group" refers to an aryl substituted alkyl radical such as benzyl and is included in the alkyl group. Furthermore, the term "alkylaryl group" refers to an alkyl-substituted aryl radical and is included in the aryl group.

Throughout this specification, the term “growth anion” may refer to an anion in which an anion in a molecule is maintained without extinction while the molecular weight is increased by polymerization of the molecule.

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

One embodiment of the present invention is a lactam; initiator; and a reaction activator; and a prepolymer that is a polymer of a first mixture, and a polyamide resin that is a reaction product of a second mixture containing a molecular weight modifier.

In the polyamide resin according to an exemplary embodiment of the present invention, in the process of polymerizing polyamide from a cyclic monomer, a caprolactamate reactive group, which is an end group of a polyamide resin chain, and a molecular weight regulator react with each other to maintain anion activity and have a side branch structure. can be produced to increase molecular weight and improve physical properties.

In addition, in the polyamide resin according to an exemplary embodiment of the present invention, by introducing a repeating unit of a diepoxy compound or a repeating unit of a diamine compound in the chain, the melt viscosity increases, and mechanical properties such as elastic modulus, tensile strength, elongation, toughness, etc. The physical properties can be improved.

According to an exemplary embodiment of the present invention, the lactam may be of Formula 1 below.

[Formula 1]

Said n is an integer of 3 or more and 14 or less.

According to an exemplary embodiment of the present invention, the lactam is propiolactam, valerolactam, ε-caprolactam, heptanolactam, octanolactam, nonano It may be one selected from the group consisting of lactam (nonanolactam), decanolactam (decanolactam), undecanolactam (undecanolactam), dodecanolactam (dodecanolactam), and combinations thereof. More specifically, the lactam is preferably ε-caprolactam. By selecting the lactam from the above, the mechanical properties of the polyamide resin can be controlled and deactivation of growth anions can be prevented.

According to an exemplary embodiment of the present invention, the ε-caprolactam exists as a solid at room temperature and has very high wettability, so it is easy to absorb moisture in the atmosphere and dissolve in a liquid state. do. By removing the moisture as described above, it is possible to prevent the polymerization of polyamide 6 from not being polymerized by inactivating the activated anions during anionic polymerization, or from polymerization to a low molecular weight even if it is polymerized.

According to an exemplary embodiment of the present invention, the content of the lactam may be 2500 parts by mole or more and 10000 parts by mole or less based on 100 parts by mole of the initiator. Specifically, the content of the lactam may be 3000 mole parts or more and 9000 mole parts or less, 4000 mole parts or more and 8000 mole parts or less, 5000 mole parts or more and 7000 mole parts or less, or 5000 mole parts or more and 6000 mole parts or less with respect to 100 mole parts of the initiator. More specifically, the content of the lactam is preferably 5000 parts by mole. By controlling the content of the lactam within the above-described range, the mechanical properties of the polyamide resin can be controlled and the molecular weight of the polyamide resin can be controlled.

According to an exemplary embodiment of the present invention, the initiator may be a caprolactam-based ionic compound or a biscaprolactam-based compound represented by Formula 2 below.

[Formula 2]

Wherein R ₁ may be a linear or branched substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, or a substituted or unsubstituted arylene group. Specifically, R ₁ is a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C3 to C30 cycloalkylene group, a substituted or unsubstituted C1 to C30 heterocycloalkylene group, a substituted or unsubstituted C6 to C30 Arylene group, substituted or unsubstituted C1 to C30 heteroarylene group, substituted or unsubstituted C1 to C30 alkoxyylene group, substituted or unsubstituted C3 to C30 cycloalkoxyylene group, substituted or unsubstituted C1 to C30 heterocyclo It may be an alkoxyylene group, a substituted or unsubstituted C6 to C30 aryloxyylene group, or a substituted or unsubstituted C1 to C30 heteroaryloxyylene group. By selecting the initiator from the above, the polymerization reaction rate can be controlled.

According to an exemplary embodiment of the present invention, the caprolactam-based ionic compound may be sodium caprolactam. By selecting the caprolactam-based ionic compound from the above, it is possible to control the polymerization reaction rate without generating a separate by-product, and to promote the generation of growth anions.

According to an exemplary embodiment of the present invention, the biscaprolactam-based compound is terephthaloyl bis-caprolactam, isophthaloyl bis-caprolactam, adipoyl biscaprolactam bis-caprolactam), 2,3-diethylsuccinoyl biscaprolactam (2,3-diethylsuccinoyl bis-caprolactam), sebacoyl bis-caprolactam, benzene phosphoryl bis-caprolactam ), may be one selected from the group consisting of dithioterephthaloyl bis-caprolactam and combinations thereof. Specifically, the biscaprolactam-based compound is preferably terephthaloyl bis-caprolactam. More specifically, the biscaprolactam-based compound has caprolactamate reactive groups at both ends, and R ₁ may contain various structures as long as the anion polymerization reaction is not inhibited. By selecting the biscaprolactam-based compound from the above, it is possible to control the polymerization reaction rate without generating a separate by-product, and to promote the generation of growth anions.

According to an exemplary embodiment of the present invention, the reaction activator is N-acetylcaprolactam, N-acetyllaurolactam, N-acetylpropiolactam, N -acetylvalerolactam (N-acetylvalerolactam), N-acetylε-caprolactam (N-acetylε-caprolactam), N-acetyl heptanolactam (N-acetylheptanolactam), N-acetyloctanolactam (N-acetyloctanolactam), N-acetylnonanolactam, N-acetyldecanolactam, N-acetylundecanolactam, N-acetyldodecanolactam, and their It may be one selected from the group consisting of combinations. By selecting the reaction activator from the above, it is possible to effectively activate the polymerization reaction.

According to an exemplary embodiment of the present invention, the content of the reaction activator may be 25 mol parts or more and 100 mol parts or less with respect to 100 mol parts of the initiator. Specifically, the content of the reaction activator may be 30 mol parts or more and 95 mol parts or less, 35 mol parts or more and 90 mol parts or less, 40 mol parts or more and 85 mol parts or less, 45 mol parts or more and 80 mol parts or less, or 50 mol parts or more and 75 mol parts or less with respect to 100 mol parts of the initiator. have. More specifically, the content of the reaction activator is preferably 50 mol parts based on 100 mol parts of the initiator. By controlling the content of the reaction activator in the above-described range, it is possible to effectively activate the polymerization reaction.

According to an exemplary embodiment of the present invention, the molecular weight modifier may be one selected from the group consisting of a diepoxide-based compound, a diamine-based compound, and a combination thereof. As described above, by using the molecular weight modifier as described above, the molecular weight of the polyamide resin can be improved, and mechanical properties and viscosity can be controlled by forming a branched chain.

According to an exemplary embodiment of the present invention, the diepoxide-based compound may be of the following formula (3).

[Formula 3]

R ₂ may be a straight-chain or branched substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, or a substituted or unsubstituted arylene group. Specifically, R ₂ is a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C3 to C30 cycloalkylene group, a substituted or unsubstituted C1 to C30 heterocycloalkylene group, a substituted or unsubstituted C6 to C30 Arylene group, substituted or unsubstituted C1 to C30 heteroarylene group, substituted or unsubstituted C1 to C30 alkoxyylene group, substituted or unsubstituted C3 to C30 cycloalkoxyylene group, substituted or unsubstituted C1 to C30 heterocyclo It may be an alkoxyylene group, a substituted or unsubstituted C6 to C30 aryloxyylene group, or a substituted or unsubstituted C1 to C30 heteroaryloxyylene group. By selecting the diamine-based compound from the above, the molecular weight of the polyamide resin can be increased, and mechanical properties and viscosity can be adjusted by forming a branched chain.

According to an exemplary embodiment of the present invention, the diamine-based compound may be of the following formula (4).

[Formula 4]

and R ₃ is a linear or branched substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, or a substituted or unsubstituted arylene group. Specifically, R ₃ is a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C3 to C30 cycloalkylene group, a substituted or unsubstituted C1 to C30 heterocycloalkylene group, a substituted or unsubstituted C6 to C30 Arylene group, substituted or unsubstituted C1 to C30 heteroarylene group, substituted or unsubstituted C1 to C30 alkoxyylene group, substituted or unsubstituted C3 to C30 cycloalkoxyylene group, substituted or unsubstituted C1 to C30 heterocyclo It may be an alkoxyylene group, a substituted or unsubstituted C6 to C30 aryloxyylene group, or a substituted or unsubstituted C1 to C30 heteroaryloxyylene group. By selecting the diamine-based compound from the above, the molecular weight of the polyamide resin can be increased, and mechanical properties and viscosity can be adjusted by forming a branched chain.

According to an exemplary embodiment of the present invention, the diamine-based compound is para-phenylenediamine (PDA1) of the following formula 5, 3-(4-Aminobenzoyloxy) phenyl 4-aminobenzoate (EDA3) of the following formula 6, and It may be one selected from a combination thereof. By selecting the diamine-based compound from the above, the molecular weight of the polyamide resin can be increased, and mechanical properties and viscosity can be adjusted by forming a branched chain.

[Formula 5]

[Formula 6]

According to an exemplary embodiment of the present invention, the molecular weight modifier is a diamine-based compound or a diepoxide-based compound such as Formula 3 or Formula 4, and may have an amine reactive group or an epoxy group at both ends. The intermediate group (R ₂ or R ₃ ) may have a structure consisting of an aromatic ring such as benzyl or naphthyl in addition to the alkyl structure, but may be used without limitation if degradation or decomposition of the polymer does not occur at the processing temperature. can As described above, by having an amine reactive group or an epoxy group at both ends as a diamine-based compound or a diepoxide-based compound, the molecular weight of the polyamide resin can be increased, and mechanical properties and viscosity can be improved by forming a branched chain. can be adjusted

According to an exemplary embodiment of the present invention, the content of the molecular weight modifier may be 20 mol parts or more and 150 mol parts or less with respect to 100 mol parts of the initiator. Specifically, the content of the molecular weight modifier may be 25 mol parts or more and 125 mol parts or less, or 50 mol parts or more and 75 mol parts or less with respect to 100 parts by mol of the initiator. More preferably, the content of the molecular weight modifier is preferably 100 mol parts or less based on 100 mol parts of the initiator. By controlling the content of the molecular weight modifier within the above-described range, the molecular weight and mechanical properties of the polyamide resin can be controlled.

According to an exemplary embodiment of the present invention, the first mixture may further include a catalyst. As described above, when the first mixture further includes a catalyst, polymerization of the prepolymer for polymerizing the polyamide may be accelerated.

According to an exemplary embodiment of the present invention, the catalyst may be one selected from sodium caprolactam, N-acetyl caprolactam, and combinations thereof. By selecting the catalyst from the above, polymerization of the prepolymer for polymerizing the polyamide can be promoted.

An exemplary embodiment of the present invention provides a method for producing the polyamide resin, comprising the steps of: preparing a prepolymer by polymerizing the first mixture; and reacting the second mixture in which a molecular weight modifier is added to the prepolymer.

The method for producing a polyamide resin according to an exemplary embodiment of the present invention can easily produce a polyamide resin having an improved molecular weight in a single process without using a solvent and improve process efficiency.

According to an exemplary embodiment of the present invention, after preparing the prepolymer, drying the prepolymer may be further included. By further including; after preparing the prepolymer as described above, drying the prepolymer, the molecular weight of the polyamide resin can be easily improved without using an extruder in the polyamide manufacturing process.

1 is a schematic diagram of an extruder according to an embodiment of the present invention. According to an exemplary embodiment of the present invention, the prepolymer is polymerized and reacted to prepare the polyamide resin in a reactor 110; a first hopper 130 that communicates with the front end 111 in the reactor 110 in which the prepolymer is produced, and is formed to feed the first mixture; a second hopper 150 in communication with the middle part 113 in the reactor 110 in which the prepolymer reacts with the molecular weight regulator, and configured to prepare a second mixture by introducing the molecular weight regulator; and an outlet 170 through which the second mixture is discharged to the outside through communication with the rear end 115 in the reactor 110 after the reaction. By using the extruder as described above, the molecular weight regulator can be easily added, and by polymerizing the prepolymer to sufficiently improve the molecular weight at the beginning of the process, branched or branched chains can be easily formed in the chain of the polyamide resin.

According to an exemplary embodiment of the present invention, the method for producing the polyamide resin may be performed in a single screw extruder or a twin screw extruder. By using the single-screw extruder or twin-screw extruder as described above, the mixture can be easily mixed.

According to an exemplary embodiment of the present invention, the method for preparing the polyamide resin is preferably performed in a state in which the first mixture or the second mixture is melted. As described above, polymerization can be easily performed by carrying out the first mixture or the second mixture in a molten state, and the mixture can be easily mixed so that the polyamide resin has uniform physical properties.

According to an exemplary embodiment of the present invention, the method for producing the polyamide resin is preferably performed while removing moisture by flowing nitrogen or argon as an inert gas into the extruder. As described above, by flowing nitrogen or argon as an inert gas into the extruder to remove moisture, the molecular weight of the polyamide resin can be increased.

According to an exemplary embodiment of the present invention, the temperature of the first hopper and / or the second hopper may be 200 ℃ or less. Throughout this specification, the "hopper" may mean "inlet" or "feeding zone". Specifically, the temperature of the first hopper and/or the second hopper may be 160 °C or more and 180 °C or less. By controlling the temperature of the first hopper and/or the second hopper in the above-described range, it is possible to prevent sublimation and decomposition of the caprolactam.

According to an exemplary embodiment of the present invention, the temperature in the reactor (reaction and mixing zone) may be 200 ℃ or more and 210 ℃ or less. By controlling the temperature in the reaction furnace to be the melting temperature of the polyamide resin in the above-described range, the reaction between the molecular weight modifier and the prepolymer can occur sufficiently.

According to an exemplary embodiment of the present invention, the time it takes to prepare the polyamide resin from the first mixture in the extruder, that is, the residence time may be 30 minutes or less. Alternatively, even if the remaining time is exceeded, it is preferable not to exceed 1 hour. By controlling the residence time in the extruder as described above, it is possible to prevent deterioration or decomposition of the polyamide resin from occurring.

According to an exemplary embodiment of the present invention, when adding a molecular weight regulator to the second hopper, the second hopper is opened only when the molecular weight regulator is added, and then the second hopper is filled with nitrogen or the second hopper is can be closed As described above, it is possible to prevent moisture from being absorbed by opening or closing the second hopper.

Hereinafter, examples will be given to describe the present invention in detail. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention is not to be construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present invention to those of ordinary skill in the art.

<Preparation Example - Preparation of polyamide 6>

Polyamide 6 was prepared using ε-caprolactam as the lactam, and the specific mechanism is shown in Scheme 1 below.

[Scheme 1]

Referring to Scheme 1, one side of biscaprolactam reacted with sodium caprolactam to open the caprolactam ring, and the activated anion attacked the caprolactam monomer to remove the proton and generate a new active anion. The nucleophilic anion opened the caprolactam ring of the resulting dimer. As a result, a trimer with an active anion was produced and the anion was reacted with another caprolactam monomer. The continuous chain reaction was continued until the anion was extinguished or deactivated, whereby polyamide 6 (nylon 6) having a high molecular weight was polymerized.

According to the mechanism of Scheme 1, ε-caprolactam was subjected to ring-opening polymerization to form a polymer of polyamide 6, and then in an additional step, an anion that was further grown of the diamine-based compound was reacted with the amine group of diamine according to the mechanism of Scheme 2 below. This was done.

[Scheme 2]

According to Scheme 2, the active anion of polyamide 6 (nylon 6) reacts with an amine group through a nucleophilic attack, and the generated anion reacts with the other terminal group of biscaprolactam as an initiator, and a diamine group is added at the end of the chain polymer was obtained. Another growing anion reacted with the unreacted amine group of the diamine. As a result, two polyamide 6 (nylon 6) chains were connected to the diamine as an intermediate medium, and at the same time the anion was deactivated.

When the reaction of Scheme 2 is described in the extruder, the diamine is introduced from the beginning in the reaction step because it is a reaction that occurs below the middle part in the reactor after polymerization of caprolactam is made at the front end of the reactor of the extruder. Unlike the single process, after the polymerized caprolactam has a degree of polymerization, it reacts with diamine, which is a molecular weight regulator, to produce caprolactam, so that the degree of polymerization is higher. At this time, when an appropriate amount of diamine is added, the linking reaction occurs well because there is a high probability that the amine group of the diamine will meet the growing anion. can be relatively reduced.

In the method for preparing polyamide according to an exemplary embodiment of the present invention, the growing anion proceeds with a secondary reaction with the reacted ami group of the diamine as shown in Scheme 3 below in the middle part of the reactor to generate a side branch structure.

[Scheme 3]

<Comparative Example: Polymerization of nylon 6 by a single process>

In a single process, nylon 6, a polyamide resin, with the composition shown in Table 1 below was polymerized through ring-opening polymerization in the reactor of an extruder. Specifically, the polyamide 6 resin, nylon 6, was prepared in a state in which lactam, a monomer, and a reactant were melted in an extruder. In this single process, the composition having the components and compositions shown in Table 1 below was simultaneously introduced into the extruder, and nylon 6 having a chain connection and branching structure was prepared from the composition as a final product. Throughout this specification, "single process", "single reaction", "single extrusion process" and "single reaction extrusion process" refer to polymerizing the polyamide resin by adding a "molecular weight control agent" before forming the prepolymer in the reaction process. can mean

More specifically, caprolactam was dried in an oven at 100° C. for 24 hours and dried again in a vacuum oven at 50° C. for 48 hours to completely remove moisture. To prepare the catalyst, 1 equivalent of caprolactam was added to a round flask filled with argon and completely dissolved at 70° C., then 0.05 equivalent of sodium hydride was added and mixed well. After the generation of hydrogen stopped, the reaction was mixed well for about 10 minutes in an argon atmosphere, and then cooled to room temperature, the prepared catalyst was well pulverized and stored in a container filled with argon.

Aldrich products were used for p-phenylenediamine (PDA1, Chemical Formula 5) used as a diamine compound as a molecular weight regulator, and 3-(4-Aminobenzoyloxy) phenyl 4-aminobenzoate (EDA3, Chemical Formula 6) was synthesized by the following method. was used.

That is, 200 ml of pyridine and 20 g of resorcinol were put into a 1 L three-necked round flask, and argon was formed as an atmosphere. After lowering the temperature of the contents of the round flask to 0° C., a solution of 101 g of 4-nitrobenzoyl chloride in 250 ml of THF was slowly added and stirred. After the addition was completed, the temperature was raised to room temperature and the reaction was stirred for 24 hours. After stirring for 24 hours, the reactant was poured into 500 ml of cold 3M aqueous hydrochloric acid solution to form a precipitate, and the precipitate was filtered through a filter, dissolved in 500 ml of methylene chloride (MC), and then dissolved in 5% aqueous sodium hydroxide (NaOH) solution and water. After washing, the solvent was evaporated to dry 3-(4-(nitrobenzoyloxy)phenyl 4-nitrobenzoate). In a round flask, 150 ml of ethyl Acetate (EA) and 8 g of the 3-(4-(nitrobenzoyloxy)phenyl 4-nitrobenzoate were added and stirred, and 0.4 g of an activated palladium-carbon (Activated Pd-C (10%)) catalyst was added. While injecting hydrogen, the reaction was carried out for 6 hours at room temperature, 1 atm After the reaction as described above, filtered through silica beads, the solvent was removed and dried to 3-(4-Aminobenzoyloxy)phenyl 4-aminobenzoate (EDA3, chemical formula 6) A powder was prepared.

Caprolactam as a monomer, sodium caprolactam as an initiator, acetyl caprolactam as a reaction activator, and a diamine compound PDA1 or EDA3 as a molecular weight regulator were measured in appropriate amounts as shown in Table 1 below, mixed well to form a composition, and then added to the extruder. The composition was introduced into the twin screw extruder using a hopper, and nitrogen was continuously flowed into the extruder. The temperature in the twin screw extruder (Ba-19, Bau tech) was maintained at 140℃/160℃/180℃/210℃/210℃/210℃/230℃ from the inlet to the outlet, and the screw rotation speed was fixed at 50 rpm. did. The experiment was carried out while continuously flowing argon gas so that the polymerization reaction was not stopped due to moisture in the twin screw extruder. Nylon 6 from the ejection hole was pulverized into small pieces and dried sufficiently in a vacuum oven at 60° C. before analysis.

Comparative Example 1 below is a control that does not contain a molecular weight regulator, and is nylon 6 obtained using a ring-opening polymerization method.

lactam
content
(Molbu) initiator
content
(Molbu) reaction activator
content
(Molbu) Types of molecular weight modifiers molecular weight modifier
content
(Molbu) catalyst
content
(Molbu) Comparative Example 1 50 One 0.5 - - 0.05 Comparative Example 2 50 One 0.5 PDA 1 0.05 0.05 Comparative Example 3 50 One 0.5 PDA 1 0.10 0.05 Comparative Example 4 50 One 0.5 PDA 1 0.15 0.05 Comparative Example 5 50 One 0.5 PDA 1 0.20 0.05 Comparative Example 6 50 One 0.5 EDA 3 0.05 0.05 Comparative Example 7 50 One 0.5 EDA 3 0.10 0.05 Comparative Example 8 50 One 0.5 EDA 3 0.15 0.05 Comparative Example 9 50 One 0.5 EDA 3 0.20 0.05

The prepared nylon 6 resins of Comparative Examples 1 to 9 were prepared in the form of fibers through the injection hole, and then prepared in the form of pellets using a pelletizer.

For nylon 6 of Comparative Examples 1 to 9, the specimen obtained in the form of pellets was sufficiently dried without any post-treatment process, and then used for characterization. Specifically, the thermal characteristic analysis was measured by DSC (differential scanning calorimetry) in a nitrogen atmosphere, the melting point of each specimen was measured, and the molecular weight was measured, and the results are summarized in Table 2 below.

The molecular weight was measured using a Ubbelohde viscometer in a thermostat at 25° C. after dissolving the nylon 6 of Comparative Examples 1 to 9 in a 90% formic acid solution, and the molecular weight of the resin is the Mark-Houwink equation [η] = k It was calculated by [M]a. (Mark-Houwink constants are k = 22.6 x 103 (mL/g) and a = 0.82 for nylon 6 at 25 °C in 90% formic acid solution).

Molecular Weight
(g/mol) melting point
T _m (℃) heat of fusion △ crystal content
DSC (%) crystal content
XRD (%) Comparative Example 1 26,800 213.6 61.75 32.5 43.1 Comparative Example 2 33,000 212.9 60.04 31.6 39.0 Comparative Example 3 36,500 212.7 60.04 31.6 37.5 Comparative Example 4 33,900 213.2 59.47 31.3 36.2 Comparative Example 5 29,300 212.8 58.52 30.8 35.0 Comparative Example 6 33,900 212.2 60.23 31.7 38.8 Comparative Example 7 36,800 213.3 59.85 31.5 37.1 Comparative Example 8 35,000 212.8 59.47 31.3 36.4 Comparative Example 9 29,700 212.9 58.71 30.9 35.1

It was confirmed that nylon 6 of Comparative Example 1 without using the molecular weight modifier had a molecular weight of 26,800 g/mol.

A mechanism expected in the reactor is shown in Scheme 1 above. It can be seen that the molecular weight of the prepared nylon 6 increases up to Comparative Examples 3 and 7 in which the molecular weight modifier is added in an amount of 0.1 molar parts, and a tendency to decrease when the molecular weight modifier exceeds 0.1 molar parts was confirmed. This tendency is because the amine group portion of the diamine-based compound, which is a molecular weight regulator, reacts with the growing anion portion of nylon 6, thereby affecting the molecular weight of the entire reactant in two directions.

Specifically, looking at the above trend, two different anions react with one amine group to connect two nylon 6 to increase the molecular weight (Scheme 2), but at the same time deactivate the activated anions to stop the polymer polymerization reaction. also reduce

In addition, when different growth anions react with other amines to cause anion transfer, a branched structure is formed in the chain to form a polyamide 6 polymer chain with side branches (Scheme 3). On the other hand, when 0.1 part by mole or more of the diamine-based compound is added, the molecular weight of nylon 6 is reduced because the anion transferred to the amine group does not proceed further polymerization. That is, the growing anion does not transfer to other caprolactam, so it is inactivated, and thus the increase in molecular weight is stopped.

On the other hand, the melting point and heat of fusion as a result of the secondary thermal scanning calorimeter scan of nylon 6 were as shown in Table 2 above. In the case of pure nylon 6, one exothermic peak appears near 214 °C, which is known as the melting point of nylon. In Comparative Examples 1 to 9, it was confirmed that the melting point appeared near 214 °C. This result is interpreted as that all lactams reacted with each other and nylon 6 was well polymerized. As the amount of the diamine-based compound added increased, it was confirmed that the heat of fusion decreased. This is because the crystal fraction decreases as the diamine-based compound enters, and it was confirmed that it was consistent with the results of XRD diffraction spectroscopy.

The mechanical properties of Comparative Examples 1 to 9 were measured and analyzed according to ASTM D638 standard and summarized in Table 3 below. The elastic modulus and tensile strength were increased up to 0.1 molar parts showing a tendency for molecular weight to increase. In general, in the case of linear polymers, when the crystallinity decreases, the elastic modulus and tensile strength decrease. Although the degree of crystallinity (crystallinity content XRD) decreased, molecular weight branching increased and chain entanglement proceeded. Therefore, it was confirmed that the elastic modulus and tensile strength were improved by the addition of the molecular weight modifier. Elongation tends to be greatly improved when fracture occurs due to entanglement of chains with increased molecular weight. It can also affect the entanglement between chains when branched structures are formed. The absorbed energy at break (ductility or tensile strength modulus) was almost doubled due to the improvement of the elongation and elastic modulus of Comparative Examples 2 to 9. However, in Comparative Examples 4, 5, 8, and 9, in which the content of the molecular weight regulator exceeds 0.1 parts by mole, it was confirmed that the mechanical properties decreased as the content of the molecular weight regulator increased. That is, it was confirmed that the mechanical properties of Comparative Examples 4, 5, 8 and 9 tend to deteriorate compared to the mechanical properties of pure polyimide 6 due to a decrease in the strength coefficient due to a decrease in crystallinity and a decrease in the formation of a low molecular weight and branched structure. Excess molecular weight modifier inhibits the reaction of anions for chain growth and lowers the molecular weight, so it does not exhibit good mechanical performance. In the case of controlling the type and content of the molecular weight modifier, it was confirmed that it is possible to control not only the molecular weight but also the physical properties of the polyamide resin, but there is a problem with the low molecular weight.

modulus of elasticity
(MPa) The tensile strength
(MPa) elongation
(%) Absorbed energy until fracture
(J) Comparative Example 1 900 69.1 89.5 3.69 Comparative Example 2 987 74.3 131.8 7.12 Comparative Example 3 998 75.1 164.4 12.27 Comparative Example 4 956 73.8 153.4 10.78 Comparative Example 5 934 71.3 115.3 6.45 Comparative Example 6 992 73.8 128.3 7.19 Comparative Example 7 1004 75.7 170.6 13.07 Comparative Example 8 962 73.8 159.4 11.27 Comparative Example 9 927 71.5 118.3 6.32

<Example: Polymerization of nylon 6 by a two-step process>

Caprolactam was dried in an oven at 100° C. for 24 hours and again dried in a vacuum oven at 50° C. for 48 hours to completely remove moisture. To prepare the catalyst, 1 equivalent of caprolactam was added to a round flask filled with argon and completely dissolved at 70° C., then 0.05 equivalent of sodium hydride was added and mixed well. After the hydrogen generation stopped, the reaction was mixed well for about 10 minutes in an argon atmosphere, and after cooling to room temperature, the prepared catalyst was well pulverized and stored in a container filled with argon.

Aldrich products were used for p-phenylenediamine (PDA1, Chemical Formula 5) used as a diamine-based compound as a molecular weight regulator, and 3-(4-Aminobenzoyloxy) phenyl 4-aminobenzoate (EDA3, Chemical Formula 6) was synthesized in Comparative Example. This method was synthesized and used.

That is, 200 ml of pyridine and 20 g of resorcinol were put into a 1 L three-necked round flask, and argon was formed as an atmosphere. After lowering the temperature of the contents of the round flask to 0° C., a solution of 101 g of 4-nitrobenzoyl chloride in 250 ml of THF was slowly added and stirred. After the addition was completed, the temperature was raised to room temperature and the reaction was stirred for 24 hours. After stirring for 24 hours, the reactant was poured into 500 ml of cold 3M aqueous hydrochloric acid solution to form a precipitate, and the precipitate was filtered through a filter, dissolved in 500 ml of methylene chloride (MC), and then dissolved in 5% aqueous sodium hydroxide (NaOH) solution and water. After washing, the solvent was evaporated to dry 3-(4-(nitrobenzoyloxy)phenyl 4-nitrobenzoate). In a round flask, 150 ml of ethyl Acetate (EA) and 8 g of the 3-(4-(nitrobenzoyloxy)phenyl 4-nitrobenzoate were added and stirred, and 0.4 g of an activated palladium-carbon (Activated Pd-C (10%)) catalyst was added. While injecting hydrogen, the reaction was carried out for 6 hours at room temperature, 1 atm After the reaction as described above, filtered through silica beads, the solvent was removed and dried to 3-(4-Aminobenzoyloxy)phenyl 4-aminobenzoate (EDA3, chemical formula 6) A powder was prepared.

The monomer caprolactam, the initiator sodium caprolactam, the reaction activator acetyl caprolactam, and the composition ratio shown in Table 4 below were mixed well to form a composition, and then added through the first inlet (first hopper), and under the same conditions as in the single process. After polymerization in the extruder, PDA1 or EDA3, which is a diamine-based compound as a molecular weight regulator, was measured as shown in Table 4 below and introduced into the extruder through the second inlet (second hopper). These compositions and molecular weight modifiers were introduced into a twin screw extruder using a hopper, and nitrogen was continuously flowed into the extruder. The temperature in the twin screw extruder (Bautech) was maintained at 140°C/160°C/180°C/210/°C at the front end of the reactor in the direction from the inlet to the outlet, and 210°C/ 210°C/230°C at the rear end of the reactor. was maintained and the screw rotation speed was fixed at 50 rpm. The experiment was carried out while continuously flowing argon gas so that the polymerization reaction was not stopped due to moisture in the twin screw extruder. In the twin-screw extruder, the molecular weight control agent is added into the second inlet (second hopper) communicating with the middle part in the reactor, and then the second inlet is closed to proceed with injection, and the nylon 6 from the outlet is pulverized into small pieces. , were sufficiently dried in a vacuum oven at 60 °C before analysis. Throughout this specification, "two-step process", "two-step reaction", "two-step extrusion process" and "two-step reaction extrusion process" may mean adding a "molecular weight control agent" after synthesizing the prepolymer in the reaction process. have.

lactam
content
(Molbu) initiator
content
(Molbu) reaction activator
content
(Molbu) Types of molecular weight modifiers molecular weight modifier
content
(Molbu) catalyst
content
(Molbu) Comparative Example 1 50 One 0.5 - - 0.05 Example 1 50 One 0.5 PDA 1 0.25 0.05 Example 2 50 One 0.5 PDA 1 0.50 0.05 Example 3 50 One 0.5 PDA 1 0.75 0.05 Example 4 50 One 0.5 PDA 1 1.00 0.05 Example 5 50 One 0.5 PDA 1 1.25 0.05 Example 6 50 One 0.5 EDA 3 0.25 0.05 Example 7 50 One 0.5 EDA 3 0.50 0.05 Example 8 50 One 0.5 EDA 3 0.75 0.05 Example 9 50 One 0.5 EDA 3 1.00 0.05 Example 10 50 One 0.5 EDA 3 1.25 0.05

The prepared nylon 6 resins of Examples 1 to 10 were prepared in the form of fibers through the injection hole, and then prepared in the form of pellets using a pelletizer.

For nylon 6 of Examples 1 to 10, the specimens obtained in the form of pellets were sufficiently dried without any post-treatment process, and then used for characterization. Specifically, the thermal characteristic analysis was measured with DSC (differential scanning calorimetry) in a nitrogen atmosphere, the melting point of each specimen was measured, and the molecular weight was measured, and the results are summarized in Table 5 below.

Referring to Table 5 below, it was confirmed that nylon 6, which is a polyamide resin, can be obtained by direct polymerization from lactam without unreacted reactants or products due to side reactions through the method for preparing a polyamide resin according to an exemplary embodiment of the present invention. .

Molecular Weight
(g/mol) melting point
T _m (℃) heat of fusion △ crystal content
DSC (%) crystal content
XRD (%) Comparative Example 1 26,800 213.6 61.75 32.5 43.1 Example 1 38,100 212.8 60.04 31.6 38.8 Example 2 44,900 213.4 57.19 30.1 37.3 Example 3 49,000 212.7 56.81 29.9 35.0 Example 4 52,500 213.4 54.72 28.8 32.2 Example 5 50,400 212.9 50.54 26.6 29.3 Example 6 39,200 212.8 60.23 31.7 39.2 Example 7 45,700 213.2 57.95 30.5 37.4 Example 8 49,100 212.6 55.67 29.3 34.8 Example 9 52,800 213.1 54.15 28.5 32.1 Example 10 51,800 213.0 49.78 26.2 29.4

The molecular weight of nylon 6 of Comparative Example 1 and Examples 1 to 10 is summarized in Table 5 after measuring intrinsic viscosity and converting it through a conversion formula.

The mechanism expected to proceed in the reactor of the extruder is shown in Schemes 1 to 3. Specifically, referring to Schemes 1 to 3, acetyl caprolactam reacts with sodium caprolactam to open the caprolactam ring. Then, the activated anion attacks the caprolactam monomer to remove the proton and create a new active anion. The nucleophilic anion opens the caprolactam ring of the resulting dimer. The result is a trimer with an active anion, which reacts with another caprolactam monomer. This chain reaction continues until the anion disappears or becomes inactive, resulting in polymerization of nylon 6 with a high molecular weight.

The molecular weight after the addition of the diamine-based compound as a molecular weight control agent increased up to Examples 4 and 9 until diamine was added in an equivalent ratio of 1 mole part, but showed a tendency to decrease when more molecular weight control agents were added. Since the molecular weight of nylon 6 polymerized by the two-step reaction increased nearly twice as compared to the molecular weight of nylon 6 polymerized by the two-step reaction compared to Comparative Examples 2 to 9 polymerized in a single reaction, a diamine-based compound as a molecular weight regulator was added to the second inlet. It was confirmed that the growth anion of caprolactam was not disturbed by putting it into the (second hopper) and reacting it.

This is because, when a molecular weight regulator is added in a single process, the anion transfer reaction to the diamine-based compound and the growth reaction of caprolactam compete with each other, and consequently the growth reaction probability of the anion decreases. Therefore, in the single process, the content of the diamine-based compound was reduced to a small amount in order to reduce the excessive reaction with the diamine-based compound, which is a molecular weight regulator, but in the two-step process, 5 times or more of the diamine-based compound was added to the post-reaction process (prepolymer polymerization). Then, the step of reacting with the molecular weight regulator) was further activated, and it was confirmed that the molecular weight of polycaprolactam increased.

As described above in a single process, in the reaction with a diamine-based compound as a molecular weight regulator, two different anions react with one amine group to connect two nylon 6 to increase the molecular weight (Scheme 2 above), but at the same time activated It also reduces the molecular weight because polymerization is stopped by inactivating anions. When another growing anion reacts with another diamine-based compound to cause anion transfer, a branched structure is formed in the chain to produce a polyamide resin having side branches (Scheme 3 above). On the other hand, in the two-step (two-step) process, only caprolactam is already polymerized at the front end of the reactor of the extruder, and the chain grows to increase the molecular weight. The molecular weight is increased by almost two times compared to a single process. When 1 mole part or more of the amine group is added in an equivalent ratio of 1 equivalent ratio, the molecular weight decreases because the anion transferred to the amine group can no longer react with the terminal anion of another polymer. As a result, by using the method for producing a polyamide resin according to an exemplary embodiment of the present invention, the molecular weight can be maximally increased by controlling the content of the molecular weight modifier.

Table 5 summarizes the melting point and heat of fusion as a result of the secondary thermal scanning calorimeter scan of the nylon 6 resins of Examples 1 to 10. In the case of pure nylon 6, one exothermic peak appears near 214 °C, which is known as the melting point of nylon. The nylon 6 resins of Examples 1 to 10 showed a melting point near 214° C. as in the case of a single process. This result means that all the monomers reacted perfectly with each other and nylon 6 was well polymerized, as in Comparative Examples 2 to 9, which is the single process. However, as the amount of the diamine-based compound added as a molecular weight control agent increased compared to the single process, the heat of fusion showed a tendency to decrease, which is because the crystal fraction decreases as the diamine molecule enters. 2 is a graph showing wide-angle X-ray diffraction spectra of Comparative Example 1 and Examples 1 to 5; Referring to FIG. 2, Comparative Example 1 and Examples 1 to 5 confirmed that the results of X-ray diffraction spectroscopy were consistent with the results of X-ray diffraction spectroscopy because they had the same structure regardless of whether or not the molecular weight modifier was added or the amount added.

Figure 3 (a) is a graph showing the viscosity rheological properties of the nylon 6 resin of Comparative Example 1 and Examples 1 to 5 measured by a rotation rheology measuring instrument. Figure 3 (b) is a graph showing the viscosity rheological properties of the nylon 6 resin of Comparative Example 1 and Examples 6 to 10 measured by a rotation rheology measuring instrument. Figure 4 (a) is a graph showing the measurement of the storage modulus (Storage modulus) of Comparative Example 1 and Examples 1 to 5 nylon 6 resin. 4 (b) is a graph showing the measurement of the loss modulus (Loss modulus) of the nylon 6 resin of Comparative Example 1 and Examples 1 to 5. Figure 4 (c) is a graph showing the measurement of the storage modulus (Storage modulus) of Comparative Example 1 and Examples 6 to 10 nylon 6 resin. 4 (d) is a graph showing the measurement of the loss modulus (Loss modulus) of the nylon 6 resins of Comparative Example 1 and Examples 6 to 10. Referring to FIGS. 3 and 4 , it was confirmed that Examples 1 to 10 had greater viscosity and modulus values than Comparative Example 1 over the entire vibration frequency range.

This tendency was particularly noticeable at low frequencies, and a strong shear reduction was observed. As can be seen in FIGS. 3(a) and 3(b), the melt viscosity greatly increases until the content of the diamine-based compound becomes 1 molar part. This is because chain entanglement increases. On the other hand, when the diamine-based compound in a molar ratio of 1.25 or more was added, the molecular weight of nylon 6 decreased, and a relatively small shear reduction phenomenon was observed compared to the composite having a content of 1 molar ratio or less. The diamine-based compound entangled the polymer chain of nylon 6 and increased the molecular weight, so it showed solid or rubber-like viscoelastic behavior in the low frequency range. The dependence of melt viscosity on molecular weight in an entangled linear chain generally obeys the 3.4 exponential law. In the case of a linear chain, a change in the molar mass of the diamine-based compound as shown in FIG. 2 can increase the viscosity up to 10 times. Therefore, it was confirmed that the significant increase of 100 times or more in the melt viscosity of diamines with strong shear thinning behavior was not explained by the increase of simple molecular weight alone.

The exceptional increase in the melt viscosity of nylon 6 described above can be expected to be due to the structural change of the polymer chain. One of the structural changes of the polymer chain is a gel-like cross-linked structure, but the three-dimensionally cross-linked polymer cannot be in a molten state and does not flow, so macroscopic viscous flow is impossible. And it was confirmed by a particle size analyzer that the cross-linked polymer, that is, the cross-linked particles, was insoluble, but the nylon 6 resins of Comparative Examples 1 to 9 and Examples 1 to 10 were completely dissolved without residual particles in formic acid. Even if a cross-linking reaction occurs, the volume occupied by the cross-linked particles is too small to change the rheological properties as shown in FIGS. 3 and 4 so much, so that the enormous increase in viscosity or storage modulus cannot be explained. Since the crosslinked particles are insoluble in the melt, their contribution to viscosity is significantly smaller according to Einstein's recognition. Similar to the results of Comparative Examples 1 to 9 prepared in a single process, another fact that proves that the change in rheological properties of Examples 1 to 10 prepared in a two-step process is not due to gel formation is due to the cross-linked structure. The rheological properties should continue to increase as more diamine-based compounds, which are molecular weight regulators, are added, but looking at the example results, the rheological value reached a peak of 1, which is the amount of the diamine-based compound of Example 4 or 9 After molar parts, they decreased, which cannot be explained in the context of the crosslinking reaction. Because in the case of Example 5 or Example 10, as the amount of the molecular weight modifier that improves these properties increases, more crosslinking reactions must occur, which leads to an increase in all rheological properties according to the generation of crosslinked particles, but the results tend to decrease showed This shows that the increase in rheological properties is not due to the cross-linking reaction. Another evidence is that these prepared resins can be reworked many times, while the products resulting from the crosslinking reaction cannot be melted, making reprocessing difficult.

Another chain geometry according to the interpretation of rheological behavior is branching. The caprolactam anion may react with the amine group of the diamine-based compound, that is, the amine group through a chain linking reaction. As shown in Scheme 3, when two growing polyamide 6 molecules are linked together, molecular weight increases, entanglement between chains increases, and viscosity may increase due to slow relaxation. The diamine-based compound can easily react with the lactam anion to form a three-branched structure under extruder conditions. When this reaction occurs on both sides of the diamine-based compound, a 4-branched molecule may be formed. However, the formation of a 4-branched molecule is unlikely to occur due to steric interference in the 3-branched molecule. The melt viscosity of a branched polymer increases exponentially with the number of entanglements per branch (η ₀ ~ (Ma/Me) ^3/2 exp(νM _a /M _e ), where M _a is the molecular weight of the branch chain and , M _e is the entangled molecular weight, and ν is a constant) Therefore, the resulting branched structure may have a viscosity increase of 10 times or more due to the increased branching even if the molecular weight is less than that of pure nylon 6. This change in rheological properties shows the same behavior regardless of the type of diamine-based compound added, suggesting that this reaction mechanism is a reasonable inference. And the reason why it was possible to add an excess of diamine-based compound in the two-step process than in the case of the single process is because the reaction in which the caprolactam anion grows does not compete with the transition reaction to the diamine-based compound, so a relatively large number of anions It shows that it can react with diamine-based compounds.

The mechanical properties of Examples 1 to 10 were measured and analyzed according to ASTM D638 standard, and summarized in Table 6 below. FIG. 5 is a graph showing (a) elastic modulus, (b) tensile strength, (c) elongation, and (d) absorbed energy up to breakage of Comparative Example 1 and Examples 1 to 10. FIG.

modulus of elasticity
(MPa) The tensile strength
(MPa) elongation
(%) Absorbed energy until fracture
(J) Comparative Example 1 900 69.1 89.5 3.69 Example 1 1,046 76.0 325.1 23.63 Example 2 1,073 79.7 352.4 26.15 Example 3 1,103 84.0 388.1 29.68 Example 4 1,137 88.2 445.3 35.67 Example 5 1,126 86.7 432.8 33.27 Example 6 1,047 77.5 345.0 25.38 Example 7 1,078 81.1 387.4 29.08 Example 8 1,098 85.7 430.5 32.43 Example 9 1,140 90.1 487.3 39.41 Example 10 1,127 87.8 476.5 36.92

Referring to FIGS. 5 and 6, the elastic modulus and tensile strength increased until the content of the diamine-based compound reached 1 molar part (Examples 4 and 9) as the molecular weight increased. In general, for linear polymers, when the crystallinity decreases, the elastic modulus and tensile strength decrease. However, despite the decrease in crystallinity in Examples 1 to 10, the molecular weight branching increased and chain entanglement proceeded further, so the elastic modulus and tensile strength were increased by the addition of molecular weight control.

Furthermore, Examples 1 to 10 of the present invention confirmed that the elongation was improved. The elongation rate is greatly improved when breakage occurs due to entanglement of chains with increased molecular weight. Furthermore, the branching structure proposed in the present invention may affect the entanglement between chains. Therefore, it was confirmed that the energy absorbed until fracture (toughness or tensile modulus) was increased by almost 7 to 8 times due to the improvement of nylon 6 elongation and elastic modulus of Examples 1 to 10. This shows the physical properties of the polyamide resin corresponding to the super-reinforced nylon region as a value 3 to 4 times higher than the nylon 6 resin of Comparative Examples 2 to 9 prepared by a single process. However, the mechanical properties of Examples 1 to 10 were decreased as the content of the diamine-based compound, which is a molecular weight regulator, was further increased in excess of 1 molar part. In general, the mechanical properties of polyamide 6 are inferior to those of pure polyamide 6 due to a decrease in the strength modulus due to a decrease in crystallinity and a decrease in the formation of a low molecular weight and branched structure. However, in Examples 1 to 10, which is an exemplary embodiment of the present invention, the diamine-based compound forms a structure having side branches in the polyamide resin, so that not only the molecular weight but also the mechanical properties of the resin can be significantly increased, and the physical properties can be adjusted according to the requirements. It was confirmed that it is possible.

After all, in the method for producing a polyamide resin according to an exemplary embodiment of the present invention, the prepolymer is polymerized and then the prepolymer is reacted with a diamine-based compound or a diepoxy compound as a molecular weight regulator to reduce the deactivation of growth anions and increase the activity of the reaction to increase the activity of the polyimide It was confirmed that the molecular weight and mechanical properties of the resin could be improved. Specifically, when a double hopper extruder is used in the polyimide resin manufacturing process, a diamine-based compound or a diepoxy compound, which is a molecular weight control agent, is added to the second hopper to react, thereby reducing the deactivation of growth anions and increasing the activity of the reaction. Furthermore, when the double hopper extruder cannot be used, after drying the polyamide prepared in the extruder, a diamine-based compound or a diepoxy compound, which is a molecular weight regulator, is added to the extruder at a certain ratio and re-extruded, thereby reducing the deactivation of growth anions It was possible to improve the molecular weight and mechanical properties of the polyimide resin by increasing the activity of the reaction. In all of the above cases, it was confirmed that the error in physical properties did not exceed + 5%, and through this, the growth anions in the polyamide resin prepared by the extruder were not immediately deactivated and the active state in the polyamide resin not in contact with air was maintained. It was confirmed that it was maintained for a long time.

In the above, although the present invention has been described by way of limited examples, the present invention is not limited thereto, and the technical idea of the present invention and the claims to be described below by those of ordinary skill in the art to which the present invention pertains Of course, various modifications and variations are possible within the equivalent range of the range.

Reactor: 110
Front end: 111
Middle:113
rear end: 115
Outlet: 170
Extruder: 100
1st hopper: 130
2nd hopper: 150

Claims (14)

lactam; initiator; and a reaction activator; a prepolymer as a polymer of a first mixture, and a polyamide resin as a reaction product of a second mixture containing a molecular weight modifier. The method according to claim 1,
The lactam is a polyamide resin of Formula 1 below:
[Formula 1]

Said n is an integer of 3 or more and 14 or less. The method according to claim 1,
The content of the lactam is 2500 parts by mole or more and 10000 parts by mole or less based on 100 parts by mole of the initiator. The method according to claim 1,
The initiator is a polyamide resin that is a caprolactam-based ionic compound or a biscaprolactam-based compound represented by the following Chemical Formula 2:
[Formula 2]

Wherein R ₁ is a linear or branched substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, or a substituted or unsubstituted arylene group. The method according to claim 1,
The reaction activator is N-acetylcaprolactam, N-acetyllaurolactam, N-acetylpropiolactam, N-acetylvalerolactam , N-acetylε-caprolactam, N-acetylheptanolactam, N-acetyloctanolactam, N-acetylnonanolactam ), N-acetyldecanolactam (N-acetyldecanolactam), N-acetyl undecanolactam (N-acetylundecanolactam), N- acetyl dodecanolactam (N-acetyldodecanolactam) and one selected from the group consisting of combinations thereof polyamide resin. The method according to claim 1,
The content of the reaction activator is 25 mol parts or more and 100 mol parts or less with respect to 100 mol parts of the initiator. The method according to claim 1,
The molecular weight modifier is a polyamide resin that is one selected from the group consisting of a diepoxide-based compound, a diamine-based compound, and combinations thereof. 8. The method of claim 7,
The diepoxide-based compound is a polyamide resin of Formula 3 below:
[Formula 3]

Wherein R ₂ is a linear or branched substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, or a substituted or unsubstituted arylene group. 8. The method of claim 7,
The diamine-based compound is a polyamide resin of Formula 4 below:
[Formula 4]

and R ₃ is a linear or branched substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, or a substituted or unsubstituted arylene group. The method according to claim 1,
The content of the molecular weight modifier is 20 mole parts or more and 150 mole parts or less based on 100 mole parts of the initiator. The method according to claim 1,
The first mixture is a polyamide resin that further comprises a catalyst. In the manufacturing method of the polyamide resin of claim 1,
preparing a prepolymer by polymerizing the first mixture; and
A method for producing a polyamide resin comprising a; reacting the second mixture with the addition of a molecular weight modifier to the prepolymer. 13. The method of claim 12,
After preparing the prepolymer,
The method for producing a polyamide resin further comprising; drying the prepolymer. 13. The method of claim 12,
a reactor formed so that the prepolymer is polymerized and reacted to prepare the polyamide resin;
a first hopper that communicates with the front end of the reactor in which the prepolymer is produced and is formed to feed the first mixture;
a second hopper that communicates with a middle part in the reactor where the prepolymer reacts with the molecular weight regulator, and is formed to prepare a second mixture by introducing the molecular weight regulator; and
The method for producing a polyamide resin using an extruder comprising a; the second mixture is discharged to the outside through communication with the rear end of the reactor after the reaction.

Images