KR20240044092A - Preparation method of polyamide - Google Patents

Abstract

The present invention relates to a method for producing polyamide. More specifically, the purpose of the present invention is to prepare a prepolymer by controlling the content ratio of monomers to a specific range and then performing solid phase polymerization at a temperature lower than the melt temperature (Tm). This relates to a method for producing polyamide that is easy to manufacture in the molecular weight range and can achieve excellent quality when applied to products.

Description

Method for producing polyamide {PREPARATION METHOD OF POLYAMIDE}

The present invention relates to a method for producing polyamide. More specifically, the purpose of the present invention is to prepare a prepolymer by controlling the content ratio of monomers to a specific range, and then to perform solid phase polymerization at a temperature lower than the melting temperature (Tm). This relates to a method for manufacturing polyamide that is easy to manufacture in the molecular weight range and can achieve excellent quality when applied to products.

Polyamide is generally progressed in three steps: PC (polycondensation) - Pre polymerization - Post polymerization, where post polymerization is carried out as solution polymerization or melt polymerization using a solvent. Among these, in the case of the melt polymerization method, the desired polymer weight could be obtained only when the reaction was carried out for a long time at a high temperature above the melting point of the polymer. In this way, there was a problem in that partial overpolymerization occurred due to exposure to high temperatures for a long period of time, forming a gel during the polymerization process, or causing a side reaction to terminate the reaction.

Accordingly, the process efficiency is significantly reduced and economic feasibility is low, and furthermore, the polyamide produced in this way may cause yellowing when applied to products, leading to deterioration in quality and various physical properties.

Accordingly, in the production of polyamide, research is needed on a production method that can minimize gel formation during the polymerization process as well as excellent process efficiency.

The present invention provides a method for producing polyamide that achieves excellent process efficiency and, in particular, can produce polyamide with a desired high molecular weight while minimizing gel generation during the polymerization process.

In order to solve the above problem, the present invention,

A first step of preparing a prepolymer of polyamide containing a dicarboxylic acid compound and a diamine compound; and

A second step of producing polyamide by solid-phase polymerizing the prepolymer,

In the first step, the dicarboxylic acid compound and the diamine compound are included in a molar ratio of 1:1.005 to 1:1.03,

In the second step, the prepolymer is melted by heating to 240°C to 290°C, and then the melt is cooled to 200°C to 230°C and subjected to solid phase polymerization under 3 torr to 10 torr.

A method for producing polyamide is provided.

The method for producing polyamide according to the present invention can produce polyamide of the desired high molecular weight while minimizing gel generation during the polymerization process.

In addition, the method for producing polyamide according to the present invention does not perform a polymerization process at a high temperature for a long time, which reduces the occurrence of deterioration and minimizes the occurrence of overreactions or side reactions, thereby realizing excellent process efficiency.

In addition, polyamide produced according to the above method is easy to apply to products with little yellowing and excellent physical properties.

Since the present invention can be subject to various changes and can take various forms, specific embodiments will be illustrated and described in detail below. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Additionally, the terminology used herein is only used to describe exemplary embodiments and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise,” “comprise,” or “have” are intended to designate the presence of implemented features, steps, components, or a combination thereof, and are intended to indicate the presence of one or more other features or steps, It should be understood that the existence or addition possibility of components or combinations thereof is not excluded in advance.

Additionally, in the present invention, when each component is referred to as being formed “on” or “on” each component, it means that each component is formed directly on each component, or that another component is formed on each component. This means that it can be additionally formed between layers, on an object, or on a substrate.

Polyamide is generally progressed in three steps: PC (polycondensation) - Pre polymerization - Post polymerization, where post polymerization is carried out as solution polymerization or melt polymerization using a solvent. Among these, in the case of melt polymerization, polyamide with the desired high molecular weight could be obtained only when the reaction was carried out for a long time at a high temperature above the melting point of the polymer. In this way, partial overpolymerization occurs due to exposure to high temperatures for a long period of time, and a gel is formed during the polymerization process, or a side reaction occurs and the reaction is terminated, which significantly reduces process efficiency. Moreover, polyamide produced in this way may cause yellowing when applied to products, leading to deterioration in quality and deterioration of various physical properties.

Accordingly, the present inventors controlled the content ratio of the prepolymer monomer to a specific range and then performed solid-state polymerization at a temperature lower than the melting temperature (Tm) of the prepolymer, thereby minimizing gel generation during the polymerization process and producing the desired high molecular weight. discovered that polyamide could be produced and completed the present invention.

According to the present invention, it is possible to realize excellent process efficiency by minimizing the occurrence of overreactions or side reactions, reducing the occurrence of deterioration by not performing the polymerization process at high temperature for a long time, and the polyamide produced as a result is a product with less yellowing and excellent physical properties. It is easy to apply.

Hereinafter, the polyamide production method according to one embodiment of the invention will be described in detail in each step.

(First step: Preparation step of prepolymer)

According to one embodiment of the invention, it includes a first step of preparing a prepolymer of polyamide containing a dicarboxylic acid compound and a diamine compound.

In the first step, the carboxylic acid compound and the diamine compound are included in a molar ratio of 1:1.005 to 1:1.03.

When preparing the prepolymer, it is preferable to adjust the molar ratio range of the monomers as described above, as it is possible to produce polyamide with a desired high molecular weight while minimizing gel generation in the solid phase polymerization step described later.

On the other hand, if the monomer is outside the above molar ratio range, the molecular weight may not be increased to the desired degree by solid phase polymerization.

Preferably, the dicarboxylic acid compound and the diamine compound may be 1:1.009 to 1:1.025, 1:1.012 to 1:1.023, or 1:1.019 to 1:1.023, and within the above range, the problems described above occur. It is preferable not to do so.

According to one embodiment of the invention, the preparation of the prepolymer in the first step can be performed at normal pressure and under conditions of 240 ℃ to 260 ℃, preferably, 240 ℃ to 250 ℃. . Here, normal pressure refers to the pressure without applying pressure reducing equipment such as a separate vacuum pump. For example, this may correspond to general atmospheric conditions of approximately 760 mmHg. When performed within the above range, it is preferable to maintain a uniform phase of the prepolymer.

The relative viscosity of the prepolymer may be 1.8 to 2.2, preferably 1.9 to 2.1. When preparing a prepolymer that satisfies the above range, it is preferable to manufacture polyamide with a desired high molecular weight while minimizing gel generation in the solid phase polymerization process described later.

The type of the dicarboxylic acid compound is not particularly limited, but examples include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, and dodecane. an aliphatic linear dicarboxylic acid selected from the group consisting of diacid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanodioic acid and octadecanodioic acid; Aliphatic cyclic dicarboxylic acids such as cyclohexane carboxylic acid; and aromatic dicarboxylic acids selected from the group consisting of phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid, most preferably adipic acid and sebacic acid. etc. can be used.

The type of the diamine compound is not particularly limited, but includes, for example, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminoctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane , 1,13-diaminotridecane, 1,14-diaminotetradecane, 1,15-diaminopenta decane, 1,16-diaminohexadecane, 1,17-diaminoheptadecane, 1,18- an aliphatic linear diamine selected from the group consisting of diaminooctadecane, 1,19-diaminononadecane, 1,20-diaminoicosane and 2-methyl-1,5-diaminopentane; an aliphatic cyclic diamine selected from the group consisting of cyclohexane diamine and bis-(4-aminocyclohexyl)methane; and at least one selected from the group consisting of aromatic diamines such as xylene diamine. Most preferably, meta-xylene diamine, para-xylene diamine, etc. can be used as the xylene diamine.

(Second step: preparation step of solid phase polymerization)

According to one embodiment of the invention, a second step of producing polyamide by solid-phase polymerizing the prepolymer is included.

내지 290

로 가온하여 용융시킨 뒤, 상기 용융물을 200

내지 230

으로 감온하여 3torr 내지 10torr 하에서 고상 중합한다.In the second step, the prepolymer was heated to 240

to 290

After heating and melting, the melt was heated to 200°C.

to 230

Reduce the temperature to solid phase polymerization under 3 torr to 10 torr.

Here, by performing solid phase polymerization under the conditions of reduced temperature and reduced pressure, the generation of gel can be minimized, and the degree of occurrence of overreaction or side reaction is significantly reduced, making it possible to manufacture polyamide with a desired high molecular weight. do.

Here, the prepolymer can be completely melted through the step of heating the prepolymer to the above-mentioned range, and if heated below the above temperature, the melting of the prepolymer is not sufficient and the powder for solid phase polymerization may not be produced uniformly. If the temperature exceeds the above temperature, the prepolymer may be thermally decomposed at high temperature. The melting temperature of the prepolymer is preferably 250°C to 280°C. Within the above temperature range, powder production is easy without problems with thermal decomposition of the prepolymer.

The performance time of the heating step of the prepolymer is not particularly limited as long as it is within the range where the prepolymer is sufficiently melted, and is preferably performed for 5 to 30 minutes or 10 to 20 minutes, but is not limited thereto. no.

내지 230

으로 감온하여 3 torr 내지 6 torr 하에서 고상 중합하는 단계를 수행한다.Next, the melt was heated to 200

to 230

Reduce the temperature to 3 torr to 6 torr and perform solid phase polymerization.

Here, by performing solid phase polymerization under reduced pressure conditions at a temperature in a range relatively lower than the melting temperature for the molten prepolymer, gel generation can be minimized and the degree of occurrence of overreaction or side reaction is significantly reduced, thereby achieving the purpose. This is desirable because it is possible to produce polyamide with a high molecular weight.

If solid-state polymerization is performed below the above temperature, the polymerization rate is slow and it may take a long time to achieve the target molecular weight. If solid-state polymerization is performed above the above temperature, solid-state polymerization is close to the melting point of the prepolymer. It gets difficult. The temperature at which the solid phase polymerization is performed is preferably 210°C to 230°C. Polyamide of the target molecular weight can be easily produced during solid phase polymerization for 1 hour within the above temperature range.

Additionally, when the solid phase polymerization is performed in excess of 10 torr, the polymerization rate is slow and it may take a long time to achieve the target molecular weight. The pressure at which the solid phase polymerization is performed is preferably 5 torr to 6 torr. Polyamide of the target molecular weight can be easily produced during solid phase polymerization for 1 hour within the above pressure range.

Polyamide manufactured according to an embodiment of the above-described invention may have a relative viscosity of 2.4 to 12.0, preferably 2.4 to 6.0 or 2.4 to 3.9.

When within the above range, the gel concentration of the polymer is very low, making it easy to process and especially easy to apply to food packaging films and injection molded products.

Hereinafter, the operation and effects of the invention will be described in more detail through specific examples of the invention. However, these examples are merely presented as examples of the invention, and the scope of the invention is not determined by them.

[Examples and Comparative Examples]

Example 1

Approximately 1.55 kg (10.63 mol) of Adipic acid was added to the 10L reactor and melted at 160°C. After the adipic acid was completely melted, about 1.480 kg of mXDA (10.87 mol, 1.023 mol of mXDA compared to 1 mol of adipic acid) was added dropwise to proceed with the reaction. The internal temperature was raised from the beginning of the dripping process so that the internal temperature reached 245°C at the end of the mXA dripping process. mXDA was constantly added for 2 hours using a metering pump, and the resulting condensation water was removed out of the reactor. During the condensation reaction, the internal pressure was maintained at normal pressure. After completion of m The relative viscosity of the prepolymer was 1.96.

Next, the prepolymer was added to a kneader reactor capable of high shear mixing, melted at about 260°C, and lowered to 220°C to make powder. The prepolymer prepared as a powder was subjected to solid phase polymerization by reducing the pressure to 6 torr at about 220°C. After solid phase polymerization was performed for 1 hour, the reactant was recovered to obtain the final polyamide.

Example 2

Approximately 1.55 kg (10.63 mol) of Adipic acid was added to the 10L reactor and melted at 160°C. After adipic acid was completely melted, about 1.477 kg (10.85 mol, mXDA 1.020 mol compared to 1 mol of adipic acid) was added dropwise to proceed with the reaction. The internal temperature was raised from the beginning of the dripping process so that the internal temperature reached 245°C at the end of the mXA dripping process. mXDA was constantly added for 2 hours using a metering pump, and the resulting condensation water was removed out of the reactor. During the condensation reaction, the internal pressure was maintained at normal pressure. After completion of m The relative viscosity of the prepolymer was 1.94.

Next, the prepolymer was added to a kneader reactor capable of high shear mixing, melted at about 260°C, and lowered to 220°C to make powder. The prepolymer prepared as a powder was subjected to solid phase polymerization by reducing the pressure to 6 torr at about 220°C. After solid phase polymerization was performed for 1 hour, the reactant was recovered to obtain the final polyamide.

Example 3

Approximately 1.55 kg (10.63 mol) of Adipic acid was added to the 10L reactor and melted at 160°C. After the adipic acid was completely melted, the reaction was carried out by adding about 1.475 kg of mXDA (10.83 mol, 1.019 mol of mXDA compared to 1 mol of adipic acid) dropwise. The internal temperature was raised from the beginning of the dripping process so that the internal temperature reached 245°C at the end of the mXA dripping process. mXDA was constantly added for 2 hours using a metering pump, and the resulting condensation water was removed out of the reactor. During the condensation reaction, the internal pressure was maintained at normal pressure. After completion of m The relative viscosity of the prepolymer was 2.18.

Next, the prepolymer was added to a kneader reactor capable of high shear mixing, melted at about 260°C, and lowered to 220°C to make powder. The prepolymer prepared as a powder was subjected to solid phase polymerization by reducing the pressure to 6 torr at about 220°C. After solid phase polymerization was performed for 1 hour, the reactant was recovered to obtain the final polyamide.

Comparative Example 1

Approximately 1.55 kg (10.63 mol) of Adipic acid was added to the 10L reactor and melted at 160°C. After the adipic acid was completely melted, the reaction was carried out by adding about 1.475 kg of mXDA (10.83 mol, 1.019 mol of mXDA compared to 1 mol of adipic acid) dropwise. The internal temperature was raised from the beginning of the dripping process so that the internal temperature reached 245°C at the end of the mXA dripping process. mXDA was constantly added for 2 hours using a metering pump, and the resulting condensation water was removed out of the reactor. During the condensation reaction, the internal pressure was maintained at normal pressure. After completion of m The relative viscosity of the prepolymer was 2.18.

Next, the prepolymer was added to a kneader reactor capable of high shear mixing, melted at about 260°C, and then pressure reduced to 10 torr, and melt polymerization was performed for 15 minutes. After melt polymerization was performed, the reactant was recovered to obtain the final polyamide.

(Relative viscosity=2.88, gel concentration=0.7%)

Comparative Example 2

Approximately 1.55 kg (10.63 mol) of Adipic acid was added to the 10L reactor and melted at 160°C. After the adipic acid was completely melted, the reaction was carried out by adding about 1.475 kg of mXDA (10.83 mol, 1.019 mol of mXDA compared to 1 mol of adipic acid) dropwise. The internal temperature was raised from the beginning of the dripping process so that the internal temperature reached 245°C at the end of the mXA dripping process. mXDA was constantly added for 2 hours using a metering pump, and the resulting condensation water was removed out of the reactor. During the condensation reaction, the internal pressure was maintained at normal pressure. After completion of m The relative viscosity of the prepolymer was 2.18.

Next, the prepolymer was added to a kneader reactor capable of high shear mixing, melted at about 260°C, and then pressure reduced to 10 torr, and melt polymerization was performed for 35 minutes. After melt polymerization was performed, the reactant was recovered to obtain the final polyamide.

(Relative viscosity=3.9, gel concentration=1.8%)

Comparative Example 3

Approximately 1.55 kg (10.61 mol) of Adipic acid was added to the 10L reactor and melted at 160°C. After adipic acid was completely melted, about 1.589 kg of mXDA (11.67 mol, 1.1 mol of mXDA compared to 1 mol of adipic acid) was added dropwise to proceed with the reaction. The internal temperature was raised from the beginning of the dripping process so that the internal temperature reached 245°C at the end of the mXA dripping process. mXDA was constantly added for 2 hours using a metering pump, and the resulting condensation water was removed out of the reactor. During the condensation reaction, the internal pressure was maintained at normal pressure. After completion of m

Next, the prepolymer was added to a kneader reactor capable of high shear mixing, melted at about 260°C, and lowered to 220°C to make powder. The prepolymer prepared as a powder was subjected to solid phase polymerization by reducing the pressure to 6 torr at about 220°C. After solid phase polymerization was performed for 1 hour, the reactant was recovered and the relative viscosity (RV) and gel concentration were measured.

(Relative viscosity = 2.2, gel concentration = zero %)

[Experimental Example 1: Analysis of physical properties of polyamide]

In Examples and Comparative Examples, the physical properties of polyamide were evaluated through the following method, and the results are listed in Table 1.

(1) Relative Viscosity

1g of the polyamide sample prepared in Examples and Comparative Examples was taken and dissolved in 100ml sulfuric acid for 24 hours. The constant temperature water bath was maintained at 25°C and the relative viscosity was measured using an Ubberod viscometer, and the results are listed in Table 1.

(2) Gel concentration (wt%)

1 g of the polyamide sample prepared in Examples and Comparative Examples was taken and dissolved in 100 ml sulfuric acid for 24 hours. Using a glass filter of known weight, the sulfuric acid solution containing the polyamide was passed through the glass filter, washed three times with ethanol and acetone, and thoroughly dried in an oven at 80°C. The gel concentration (wt%) was confirmed by measuring the change in weight of the dried glass filter, and the results are listed in Table 1.

division relative viscosity Gel concentration (wt%) Example 1 2.45 Zero Example 2 2.88 Zero Example 3 3.90 0.3 Comparative Example 1 2.88 0.7 Comparative Example 2 3.90 1.8 Comparative Example 3 2.20 Zero

As can be seen from the experimental data in Table 2, in the examples in which the prepolymer was prepared by controlling the content ratio of monomers to a specific range and then solid-phase polymerization was performed at a temperature lower than the melting temperature (Tm), the gel was formed in the polymerization process. It was confirmed that the occurrence was significantly reduced and that excellent quality polyamide with the desired high molecular weight (=relative viscosity) could be manufactured.

In the case of the melt polymerization of Comparative Examples 1 and 2, it was confirmed that a gel was generated due to partial overpolymerization under high temperature conditions above the melting point, showing a significantly higher gel concentration compared to the Example. In the case of Comparative Example 3, it was confirmed that the solid-state polymerization was performed under conditions outside the molar ratio range of the monomers described herein, making it difficult to manufacture high molecular weight polyamide, and accordingly, the increase in molecular weight compared to the Example was insignificant.

Claims (7)

A first step of preparing a prepolymer of polyamide containing a dicarboxylic acid compound and a diamine compound; and
A second step of producing polyamide by solid-phase polymerizing the prepolymer,
In the first step, the dicarboxylic acid compound and the diamine compound are included in a molar ratio of 1:1.005 to 1:1.03,
In the second step, the prepolymer is melted by heating to 240°C to 290°C, and then the melt is reduced to 200°C to 230°C to perform solid phase polymerization under 3 torr to 10 torr.
Polyamide manufacturing method.
According to paragraph 1,
The first step is performed at 240°C to 260°C under normal pressure,
Polyamide manufacturing method.
According to paragraph 1,
The relative viscosity of the prepolymer is 1.8 to 2.2.
Polyamide manufacturing method.
According to paragraph 1,
The dicarboxylic acid compound is,
Oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecane aliphatic linear dicarboxylic acids selected from the group consisting of diacids, heptadecanedioic acids and octadecanedioic acids; aliphatic cyclic dicarboxylic acids; and at least one selected from the group consisting of aromatic dicarboxylic acids selected from the group consisting of phthalic acid, isophthalic acid, terephthalic acid and naphthalenedicarboxylic acid,
Polyamide manufacturing method.
According to paragraph 1,
The diamine compound is,
Ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminoctane , 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,13-diaminotridecane, 1,14-diaminodecane Minotetradecane, 1,15-diaminopentadecane, 1,16-diaminohexadecane, 1,17-diaminoheptadecane, 1,18-diaminoctadecane, 1,19-diaminononadecane, 1 an aliphatic linear diamine selected from the group consisting of 20-diaminoicosane and 2-methyl-1,5-diaminopentane; an aliphatic cyclic diamine selected from the group consisting of cyclohexane diamine and bis-(4-aminocyclohexyl)methane; and at least one selected from the group consisting of aromatic diamines,
Polyamide manufacturing method.
According to paragraph 1,
The relative viscosity of the polyamide is 2.4 to 12.0,
Polyamide manufacturing method.
According to paragraph 1,
The gel concentration of the polyamide is 0.5 wt% or less,
Polyamide manufacturing method.