TWI744125B - Method for manufacturing transparent polyamide copolymer - Google Patents

Abstract

The instant disclosure relates to a method for manufacturing transparent polyamide copolymer. The method includes a salt synthesizing step and a melt copolymerization step. The salt synthesizing step includes dissolving a compound represented by Chemical Formula 1 and isophthalic acid in a solvent and stirring the same for preparing a semi-aromatic salt:

Wherein R₁ and R₂, R₃ and R₄, and R₅ and R₆ are different from each other and are either H or CH₃ respectively. The melt copolymerization step includes using the semi-aromatic salt as a monomer for performing a melt copolymerization reaction. Based on the total content of the transparent polyamide copolymer prepared therefrom, the content of the compound is from 49 to 51 mole%, and the content of the isophthalic acid is from 51 to 49 mole%. Because the method provided by the instant disclosure is a 2-step synthesis method, it is able to prepare a copolymer with narrow molecular weight distribution steadily.

Description

Method for producing transparent polyamide copolymer

The present invention relates to a method for manufacturing a polyamide copolymer, and more specifically, to a method for manufacturing a transparent polyamide copolymer.

Compared with other general transparent polymers, transparent polyamide materials can exert great advantages in special types of use environments due to their excellent mechanical properties, thermal properties, corrosion resistance, and transparency. At present, transparent polyamide materials have been widely used in fuel and oil surrounding mechanical parts and electrical mechanical parts (flowmeter cover, filter cover, lighter oil tank, etc.), especially in precision optical instruments, pressure windows, observation mirrors, etc. , High-end sports equipment, special lighting covers and other fields have become irreplaceable material choices. Currently the most widely used transparent polyamide materials include, for example, DuPont’s nylon (Nylon) 6I/6T, which is composed of hexanediamine (hexanediamine), isophthalic acid (IPA, isophthalic acid) and terephthalic acid ( PTA (terephthalic acid) mixture copolymerized amorphous semi-aromatic polyamide. Nylon 6I/6T has the following structure:

In the above structural formula 1, the isophthalic acid aromatic ring on the main chain can play a role in inhibiting crystallization, so that the amorphous semi-aromatic polyamide material has a high degree of transparency, and is resistant to gas, aqueous solvents, Oil products have good barrier properties. In addition, the glass transition temperature of this material is about 125°C, so it has the advantage of easy processing. This material can be processed using general extrusion equipment, injection equipment or blow molding equipment, and the processed products are mostly suitable for packaging applications.

However, the molar ratio of terephthalic acid (PTA)/isophthalic acid (IPA) in nylon 6I/6T material is higher than 50/50 (that is, the molar ratio of terephthalic acid) When the molar content is higher than the molar content of isophthalic acid), although the increase in the content of terephthalic acid can make the semi-aromatic polyamide material have higher mechanical properties, this semi-aromatic polyamide will It exhibits crystallinity and loses transparency, and has a melting point (Tm) between 265 and 319°C and a crystallinity between 4.3 and 16.5%. In addition, at present, the synthesis of semi-aromatic polyamide materials is generally carried out under high temperature and high pressure (for example, above 16 atmospheres). Personnel safety considerations are also strictly required.

Therefore, the development of a method that can carry out the melt copolymerization of semi-aromatic polyamides under atmospheric conditions is currently one of the important goals in this technical field.

In order to solve the above technical problems, the present invention provides a method for manufacturing a transparent polyamide copolymer, which adopts a two-step synthesis method to stably synthesize a transparent polyamide copolymer with a narrow molecular weight distribution under a normal pressure environment.

One embodiment of the present invention provides a method for producing a transparent polyamide copolymer, which includes a salt synthesis step and a melt copolymerization step. The salt synthesis step includes combining the compound represented by the following chemical formula 1 and isophthalic acid Dissolve in the solvent and stir to prepare half of the aromatic salt:

Wherein R ₁ and R ₂ are different from each other and are each H or CH ₃ , R ₃ and R ₄ are different from each other and are each H and CH ₃ , and R ₅ and R ₆ are different from each other and are each H or CH ₃ . The melt copolymerization step includes adding a semi-aromatic salt as a monomer to a reactor to perform a melt copolymerization reaction, thereby obtaining the transparent polyamide copolymer. Based on the total amount of the transparent polyamide copolymer, the content of the compound is 49 to 51 mol%, and the content of isophthalic acid is 51 to 49 mol%.

In a preferred embodiment, the transparent polyamide copolymer is an amorphous polymer.

In a preferred embodiment, the transparent polyamide copolymer has a weight-average molecular weight between 25,000 and 35,000 g/mole.

In a preferred embodiment, the solvent is ethanol.

In a preferred embodiment, the salt synthesis step further includes stirring at a temperature of 70 to 90° C. for at least 24 hours.

In a preferred embodiment, the salt synthesis step further includes drying at a temperature of 70 to 90° C. after stirring for at least 24 hours.

In a preferred embodiment, the melt copolymerization step further includes performing a melt copolymerization reaction at a pressure of 12 to 18 atmospheres.

In a preferred embodiment, the melt copolymerization step further includes stirring at a temperature of 180°C to 200°C for at least 1 hour, and then raising the temperature to a temperature of 240°C to 270°C and stirring for at least 2 hours.

In a preferred embodiment, the melt copolymerization step further includes stirring at a temperature of 180°C to 200°C for at least 1 hour, and changing the temperature of the reactor from 25°C within 30 minutes to 1 hour. Increase the temperature to at least 180°C.

In a preferred embodiment, the melt copolymerization step further includes stirring at a temperature of 240°C to 270°C for at least 2 hours, and then drying at a temperature of 70°C to 90°C to obtain the The transparent polyamide copolymer.

The main technical means of the present invention is that the method for preparing the transparent polyamide copolymer provided by the present invention is to first form a salt with a specific structure with the compound represented by chemical formula 1 and terephthalic acid, and then make the salt A melt copolymerization reaction is performed to synthesize a transparent semi-aromatic polyamide with a narrow molecular weight distribution under a normal pressure environment.

The following specific examples are used to illustrate the implementation of the "transparent polyamide copolymer manufacturing method" disclosed in the present invention. Those with ordinary knowledge in the technical field of the present invention can understand the content of the present invention from the content disclosed in this specification. Advantages and effects. The present invention can be adopted by other different tools Implementation or application of the specific embodiments, various details in this specification can also be based on different viewpoints and applications, and various modifications and changes can be made without departing from the spirit of the present invention. The following embodiments will further describe the related technical content of the present invention in detail, but the disclosed content is not intended to limit the technical scope of the present invention.

First of all, as mentioned above, for the existing transparent polyamide copolymer material nylon 6I/6T, an increase in the content of terephthalic acid repeating units will cause the material to lose transparency. In response to this, 2-methyl-1,5-pentanediamine (hereinafter referred to as Dy) was substituted for the monomer used in the synthesis of nylon 6I/6T: hexanediamine, Furthermore, with terephthalic acid (PTA) and isophthalic acid (IPA) under normal pressure conditions, a transparent semi-aromatic polyamide (PTA-co-IPA-co-Dy) can be synthesized, as represented by chemical formula 2 below .

In Chemical Formula 2, R ₁ and R ₂ are different from each other and are each H or CH ₃ , R ₃ and R ₄ are different from each other and are each H and CH ₃ , and R ₅ and R ₆ are different from each other and are each H or CH ₃ , And n is an integer greater than 0.

In particular, in the above polyamide copolymer represented by chemical formula 2, even if the molar content ratio of terephthalic acid/isophthalic acid (PTA/IPA) is increased to 66/34, this polyamide copolymer It is still an amorphous material and has good transparency. Through research and development, the inventors of the present case confirmed that this is because 2-methyl-1,5-pentanediamine (Dy) has a chemical structure containing pendant methyl groups, which can further inhibit the crystallization of the polymer product.

However, the disadvantage of using three monomers for the polymerization reaction is that the variability of the weight average molecular weight (Mw) of the product obtained in each batch is too high, resulting in low quality stability of the applied product. Because terephthalic acid as a monomer has high rigidity, it is compatible with fatty 2-methyl 1,5-pentanediamine (Dy) The compatibility between terephthalic acid and Dy is also lower than that of isophthalic acid and Dy. Therefore, when these three monomers are used to react together, it will cause IPA-co -Dy is preferentially generated by polymerization reaction, so that the final product will become a block copolymer with (IPA-co-Dy)x-co-(PTA-co-Dy)y structure instead of the expected uniform, Random structure. In addition, under the existing normal pressure and high temperature polymerization conditions, Dy has a relatively low boiling point compared to other co-monomers that react together, and it is easy to slip out of the reactor during the polymerization reaction.

Therefore, the manufacturing method of the transparent polyamide copolymer provided by the present invention is a two-step method. In the first step, the compound represented by Chemical Formula 1 is reacted with isophthalic acid to prepare a semi-aromatic salt ; In the second step, the semi-aromatic salt prepared in the first step is used as a monomer for melt copolymerization. The manufacturing method of the transparent polyamide copolymer provided by the present invention will be described in detail below.

In Chemical Formula 1, R ₁ and R ₂ are different from each other and are each H or CH ₃ , R ₃ and R ₄ are different from each other and are each H and CH ₃ , and R ₅ and R ₆ are different from each other and are each H or CH ₃ . In other words, in the three groups of straight-chain side groups in Chemical Formula 1, the two R groups must be different from each other and be H and CH ₃ respectively. For example, in one embodiment of the present invention, R ₁ , R ₃ , and R ₅ are H (hydrogen atom), and R ₂ , R ₄ and R ₆ are methyl groups; in another embodiment of the present invention In the example, R ₁ , R ₄ and R ₅ are H, and R ₂ , R ₃ and R ₆ are methyl groups; in yet another embodiment of the present invention, R ₁ , R ₄ and R ₆ are H , And R ₂ , R ₃ and R ₅ are methyl groups; and so on, there are a total of 8 different embodiments.

First, in the first step, the compound represented by Chemical Formula 1 is used as a reactant. Therefore, before the first step, the present invention may further include a step of synthesizing the compound represented by Chemical Formula 1. In this synthesis step, 2-methyl-1,5-pentanediamine and terephthalic acid, which are not compatible with each other and have poor reactivity, are subjected to a chemical reaction in advance to amination reaction. This synthesizes the compound represented by Chemical Formula 1. The reaction formula of this synthesis step is shown in the following reaction formula 1 (synthesis of BADyT), and R ₁ to R ₆ are the same as those defined above for chemical formula 1:

Next, in the embodiment of the present invention, the obtained BADyT salt is used in the salt synthesis step. In the salt synthesis step, the BADyT compound and isophthalic acid can be dissolved in a solvent (for example, ethanol) and stirred to prepare a semi-aromatic salt. The temperature for stirring may be between 70 to 90°C, and the stirring time may be at least 24 hours, more specifically, the temperature may be 75 to 85°C, and the stirring time may be 24 to 48 hours. In addition, after stirring for at least 24 hours, drying may be performed at a temperature ranging from 70 to 90°C, more specifically at a temperature ranging from 75 to 85°C. The drying procedure can be carried out in a vacuum oven. The reaction formula of the salt synthesis step is shown in the following reaction formula 2:

The semi-aromatic salt synthesized by the salt synthesis step is represented by the following chemical formula 3, and R ₁ to R ₆ are the same as defined above for the chemical formula 1:

Next, in the second step, the melt copolymerization step, the semi-aromatic salt obtained in the salt synthesis step is added as a monomer to the reactor for melt copolymerization to obtain a transparent polyamide Copolymer. Based on the total amount of the obtained transparent polyamide copolymer, the content of the BADyT compound is 49 to 51 mol%, and the content of isophthalic acid is 51 to 49 mol%. In fact, the content ratio of BADyT compound to isophthalic acid is about 1:1. In addition, similarly, in the transparent polyamide copolymer, the repeating unit of terephthalic acid (PTA) and the repeating unit of isophthalic acid (IPA) are based on the ratio of the amine group and the carboxyl group undergoing amination reaction. The molar ratio is about 2:1.

The transparent polyamide copolymer is a non-crystalline polymer and has good transparency. The obtained product is shown in Chemical Formula 2 below.

In Chemical Formula 2, R ₁ and R ₂ are different from each other and are each H or CH ₃ , R ₃ and R ₄ are different from each other and are each H and CH ₃ , and R ₅ and R ₆ are different from each other and are each H or CH ₃ , And n is an integer greater than 0.

In the melt copolymerization step, the reaction conditions for performing the melt copolymerization reaction may include a pressure between 12 and 18 atmospheres. In addition, the melt copolymerization step may also include raising the temperature of the reactor from 25°C to at least 180°C within 30 minutes to 1 hour, and then at a temperature of 180°C to 200°C. After stirring for at least 1 hour, the temperature was raised to 240°C to 270°C and stirred for at least 2 hours. Finally, after stirring at a temperature raised to 240°C to 270°C for at least 2 hours, drying is performed at a temperature of 70°C to 90°C to obtain a transparent polyamide copolymer.

The transparent polyamide copolymer obtained by the melt copolymerization step is a non-crystalline polymer, and it is preferable that the transparent polyamide copolymer has a weight average of between 25,000 and 35,000 g/mole. The molecular weight (Mw) preferably has a weight average molecular weight between 30,000 and 32,000 g/mol. In addition, the transparent polyamide copolymer preferably has a number-average molecular weight (Mn) between 8,000 and 15,000 g/mole, and preferably has a number-average molecular weight (Mn) between 10,000 and 13,000 g/mole. Number average molecular weight. In addition, the transparent polyamide copolymer preferably has a molecular weight distribution (Ip, being Mw/Mn) between 2.5 and 3.0, and preferably has a molecular weight distribution between 2.6 and 2.9.

It is worth noting that for the compound represented by Chemical Formula 2, even if the molar ratio of the content of PTA and IPA is increased to 66:34, the compound is still an amorphous compound and retains transparency. In addition, the variability of molecular weight between these products is greatly reduced for products obtained by repeating the manufacturing method multiple times and batch polymerization. Therefore, the manufacturing method provided by the embodiment of the present invention can actually effectively solve the shortcomings of the prior art.

Next, the present invention will disclose the content of the present invention in detail through specific examples such as synthesis examples and preparation examples.

Synthesis Example 1: Synthesis of the compound represented by Chemical Formula 1 (BADyT)

20 grams of bis(2-hydroxyethyl) terephthalate (BHET) and 548 grams of 2-methyl-1,5-pentanediamine (Dy) (mole ratio: [BHET/Dy= 1/6]) and 2 grams of Zn(OAc) ₂ (weight ratio: [BHET/Zn(OAc) ₂ =100/1]) were added to a 3 liter round-bottomed flask, and stirred at 90°C for 24 hours. . Until the solid is completely dissolved in the reaction, the reactant is cooled and left for 1 hour to allow the reactant to return to room temperature. Next, the reactant was poured into 200 milliliters (mL) of RO water (the weight of the RO water was about 20 times the weight of BHET), so that the precipitate of the reactant was formed. Centrifugation is used to take out the solid precipitate and wash 6 to 8 times with about 20 to 30 milliliters of RO water. Then, the solid was dried in a vacuum oven at 80°C. The oven-dried product (BADyT) was tested and analyzed.

The thermal analysis result of the product showed that the melting point (Tm) was 173.5°C, and the decomposition temperature (Td) was 389.3°C. The result of infrared light analysis is IR (cm-1)=3308 (amino group), 1633 (amino group, broad). ¹ HNMR spectrum data are as follows (D ₂ SO ₄ ): δ8.473 (aromatic system, 8H, s), δ4.061-4.206 (amide NH-CH ₂ ,8H,m), δ3.390-3.581 (terminal NH _2- CH ₂ , 4H, m), δ 2.259 (CH ₂ , 8H, m), δ 2.187 (CH ₂ , 4H, m), δ 1.79-1.953 (CH ₃ , 12H, m). From the results of the NMR spectrum, it can be calculated that the benzene ring component H number/aliphatic carbon chain H number = 8/36. Therefore, 2-methyl-1,5-pentanediamine reacts with terephthalic acid in the copolymer The inner molar ratio is 2/3, which can prove the structural composition of the salt.

The results of elemental analysis (Elemental Analysis) of the product are as follows. Theoretical value: C (67.08%); H (8.61%); O (10.51%); N (13.80%). Detection value: C (67.10%); H (8.63%); O (10.52%); N (13.75%).

Synthesis Example 2: Synthesis of the salt-PTA-IPA-Dy used in Comparative Preparation Example 1

33.2 g (0.2 mol) of terephthalic acid (PTA), 16.6 g (0.1 mol) of isophthalic acid (IPA), 34.8 g (0.3 mol) of 2-methyl-1,5-pentane Diamine (Dy) and 500 ml of ethanol were added to a round-bottom flask, and a reflux device equipped with a condenser was used to perform reflux and stirring reaction at an external temperature of about 80 to 90°C for 24 hours. Then, the hot solution was filtered in a filtering device with a hot filtering device, and then 100 ml of hot ethanol was used to repeatedly wash the obtained solid 5 times. The washed solid product was dried in a vacuum oven at 80°C for 24 hours. The reaction formula is shown in the following reaction formula 3, where x and y are integers greater than 0:

¹ HNMR spectrum data are as follows (D ₂ SO ₄ ): δ8.620-8.740 (aromatic system, PTA 8H+IPA 3H, m), δ8.54 (aromatic system, IPA 1H, s), δ4.152-4.351 (N -CH ₂ , 12H, m), δ 2.2710 (CH ₂ , 6H, m), δ 2.189 (CH ₂ , 10H, m), δ 1.800-1.967 (CH ₃ , 8H, m). IR (cm ^-1 )=1687-1695 (aromatic ketone absorption peak). ¹ HNMR spectrum analysis shows that the molar ratio of the PTA group/IPA group/Dy group in the solid product (PTA-IPA-Dy salt) is 2.0:1.0:3.0 calculated from the integral value of the absorption peak. . The product molecular weight (FW) was 847.0 g/mol.

Preparation Example 1: Synthesis of BADyT-IPA salts (salt synthesis step)

Add 6.10 g (0.01 mol) of BADyT and 1.66 g (0.01 mol) of IPA (molar ratio of 1:1), and 100 ml of ethanol into the round-bottomed flask to equip the reflux device with condenser , The reaction is refluxed and stirred for 24 hours at an external temperature of about 80-90°C. Then, the hot solution was filtered in a filtering device with a hot filtering device, and then washed with 30 ml of hot ethanol for 5 times to obtain a solid. The washed solid product was dried in a vacuum oven at 80°C for 24 hours. The reaction formula is shown in the following reaction formula 2:

¹ HNMR spectrum data are as follows (D ₂ SO ₄ ): δ8.472-8.610 (aromatic system, BADyT 8H+IPA 3H, m), δ8.46 (aromatic system, IPA 1H, s), δ4.061-4.206 (醯Amine N-CH ₂ , 8H, m), δ 3.41-3.703 (fatty N-CH ₂ , 4H, m), δ 2.261 (CH ₂ , 6H, m), δ 2.190 (CH ₂ , 10H, m), δ 1.792-1.956 (CH ₃ , 8H, m).

Infrared light analysis results: IR (cm ^-1 )=1634-1635, 1628-1631 (absorption peak of amide). Thermal analysis result: T _{m is} not obvious, and T _d is 444.8°C. ¹ HNMR spectrum analysis shows that the molar ratio of the BADyT group to the compound IPA group in the solid product is 1.0:1.0 calculated from the integral value of the absorption peak. The molecular weight is 776 g/mol.

Preparation Example 2: Polymerization reaction of BADyT-IPA salts under normal pressure (melt copolymerization step), the first batch reaction

Add 776 grams (1.0 mol) of BADT-IPA salt synthesized in Preparation Example 1 into a 2 liter scale steel tank reactor, and slowly rise from room temperature to 230°C within 1 hour under normal pressure ( The solid completely melted at about 200°C), then stirred at 230°C for 2 hours, and stirred at 270°C for another 2 hours. Unload the product and dry the product in a vacuum oven at 80°C for 8 hours. After drying, the product is tested and analyzed. The results of physical property analysis are shown in Table 1. The reaction formula is shown in the following reaction formula 4, where n is an integer greater than 0:

¹ HNMR spectrum data are as follows (D ₂ SO ₄ ): δ8.472-8.610 (aromatic system, BADT 8H+IPA 3H, m), δ8.48 (aromatic system, IPA 1H, s), δ4.060-4.206 (aromatic Amine N-CH ₂ , 12H, m), δ 2.261 (CH ₂ , 6H, m), δ 2.190 (CH ₂ , 10H, m), δ 1.792-1.956 (CH ₃ , 8H, m) . Infrared light analysis results: IR (cm ^-1 )=1634-1635, 1628-1631 (amide absorption peak). Thermal analysis results: T _m = Amorphous with no fixed melting point, T _d at 481.3°C, and T _g at 156.2°C. ¹ HNMR spectrum analysis showed that the molar ratio of the BADT group to the compound IPA group in the solid product was 1.0:1.0 calculated from the integral value of the absorption peak. The molecular weight/molecular weight distribution is shown in Table 1.

Preparation examples 3 to 5: polymerization reaction of BADyT-IPA salts under normal pressure (melt copolymerization step), the second to fourth batches of reactions

All reaction conditions are the same as in Preparation Example 2 (the first batch reaction), and the spectral analysis of the obtained polymer product is also the same as in Preparation Example 2. The molecular weight/molecular weight distribution is shown in Table 1.

Comparative preparation example 1: Polymerization reaction of PTA-IPA-Dy salt under normal pressure (single-step synthesis method), the first batch reaction

Add 847 grams (1.0 mol) of the PTA-IPA-Dy salt synthesized in Synthesis Example 2 into a 2 liter large-scale steel tank reactor. Under normal pressure, the temperature is slowly raised from room temperature to 230 within 1 hour. ℃ (about 200 ℃ when the solid completely melted), then stirred at 230 ℃ for 2 hours, at 270 ℃ for 2 hours with stirring. Unload the product and dry the product in a vacuum oven at 80°C for 8 hours. After drying, the product is tested and analyzed. The molecular weight/molecular weight distribution is shown in Table 1. The reaction formula is shown in the following reaction formula 5, where x, y, m, and n are integers greater than 0:

Comparative preparation examples 2 to 4: polymerization reaction of PTA-IPA-Dy salts under normal pressure (single-step synthesis method), the second to fourth batches of reactions

All reaction conditions are the same as those of Comparative Preparation Example 1 (the first batch reaction), and the analysis of the obtained polymer product is also the same as Preparation Example 2. The molecular weight/molecular weight distribution is shown in Table 1.

The analysis of Mw and Mn was carried out in equivalent PMMA by size exclusion chromatography (SEC), and the solvent was Hexafluoro-2-propanol.

It can be seen from Table 1 that when the molar ratio of PTA/IPA/Dy or its derivatives in the salt compound added before the polymerization reaction is the same, the preparation methods of Preparation Examples 2 to 4 of the present invention are two steps The copolymer obtained by the copolymer preparation method has a narrow molecular weight distribution (Ip), which shows that the molecular weight of each repeating unit has a small difference, so that the composition of the copolymer is more uniform. Furthermore, the preparation methods of Preparation Examples 2 to 4 of the present invention can stably prepare a polyamide copolymer with high transparency (non-crystalline). In detail, in different production batches, compared with the molecular weight and molecular weight distribution of the polyamide copolymer of the comparative preparation example (for example, the molecular weight distribution greatly changes between 3.2 and 4.1) prepared polyamide The numerical difference between the molecular weight of the copolymer and the molecular weight distribution is very small (for example, the molecular weight distribution is between 2.6 and 2.9). Based on this, it can be confirmed that, compared with the manufacturing method of the prior art (Comparative Preparation Examples 2 to 4), the manufacturing method provided by the present invention is more stable, so that the quality of the products prepared therefrom is more stable and the yield The rate is better.

In summary, the main technical means of the present invention is that the method for producing the transparent polyamide copolymer provided by the present invention is to first form a salt with a specific structure from the compound represented by Chemical Formula 1 and isophthalic acid. Then, the salt is subjected to a melt copolymerization reaction to synthesize a transparent semi-aromatic polyamide with a narrow molecular weight distribution under a normal pressure environment.

In detail, unlike the prior art, where each comonomer is placed in a reactor to synchronize the copolymerization reaction in a single step, the present invention first reacts a specific combination of comonomers, and then melts the comonomer under normal pressure. The polymerization reaction, in this way, can overcome the difference in stiffness and reactivity between different comonomers. In addition, the manufacturing process of the present invention may further adopt a multi-stage heating process to ensure the yield of the product.

The polyamide copolymer prepared by the production method of the present invention is not only stable and transparent, but also from the experimental data provided in the specification of the present invention, the polyamide copolymer also has a fairly narrow molecular weight distribution. The difference between the molecular weights of the repeating units in the copolymer is small, which makes the composition of the copolymer more uniform. Therefore, the transparent polyamide copolymer prepared by the production method of the present invention can be well applied to various industrial products.

Although the embodiments of the present invention are disclosed in the above-mentioned more detailed manner, those with ordinary knowledge in the technical field to which the present invention belongs can understand that various modifications of the present invention can be made without departing from the scope of the present invention defined in the appended patent application. Proceed under. Therefore, further modification of the examples of the present invention will not deviate from the technical scope of the present invention.

Claims (10)

A method for producing a transparent polyamide copolymer, comprising: a salt synthesis step, which includes dissolving a compound represented by the following chemical formula 1 and isophthalic acid in a solvent and stirring to prepare a semi-aromatic Department of Salt:

Wherein R ₁ and R ₂ are different from each other and are each H or CH ₃ , R ₃ and R ₄ are different from each other and are each H or CH ₃ , and R ₅ and R ₆ are different from each other and are each H or CH ₃ ; and a melting The copolymerization step includes adding the semi-aromatic salt as a monomer to a reactor to carry out a melt copolymerization reaction, thereby obtaining the transparent polyamide copolymer; wherein the transparent polyamide copolymer is copolymerized The content of the compound is 49 to 51 mol%, and the content of isophthalic acid is 51 to 49 mol% based on the total amount of the substance. The method for producing a transparent polyamide copolymer according to claim 1, wherein the transparent polyamide copolymer is an amorphous polymer. The method for producing a transparent polyamide copolymer according to claim 1, wherein the transparent polyamide copolymer has a weight average molecular weight between 25,000 and 35,000 g/mol. The method for producing a transparent polyamide copolymer according to claim 1, wherein the solvent is ethanol. The method for producing a transparent polyamide copolymer according to claim 1, wherein the salt synthesis step further includes stirring at a temperature of 70 to 90°C for at least 24 hours. The method for producing a transparent polyamide copolymer according to claim 1, wherein the salt synthesis step further includes drying at a temperature of 70 to 90° C. after stirring for at least 24 hours. The method for producing a transparent polyamide copolymer according to claim 1, wherein the melt copolymerization step further includes performing a melt copolymerization reaction at a pressure of 12 to 18 atmospheres. The method for producing a transparent polyamide copolymer according to claim 1, wherein the melt copolymerization step further comprises: stirring at a temperature of 180°C to 200°C for at least 1 hour, and then raising the temperature to 240°C to 270°C Stir at a temperature of ℃ for at least 2 hours. The method for producing a transparent polyamide copolymer according to claim 8, wherein the melt copolymerization step further comprises: stirring at a temperature of 180°C to 200°C for at least 1 hour, and 30 minutes to 1 hour before stirring. Inside, the temperature of the reactor is increased from 25°C to at least 180°C. The method for producing a transparent polyamide copolymer according to claim 8, wherein the melt copolymerization step further comprises: after stirring at a temperature raised to 240°C to 270°C for at least 2 hours, heating at 70°C to 270°C Drying is performed at a temperature of 90°C to obtain the transparent polyamide copolymer.