TWI782323B - Diamine compound, copolymer, and method for manufacturing the same - Google Patents

Abstract

A diamine compound and method of forming the same are provided, which includes:(i)mixing a 2-methyl-1,5-pentanediamine and a terephthalate diester to form a mixture; and (ii) heating the mixture to form a diamine compound, wherein the diamine compound has a chemical structure represented by formula (I):

wherein R₁ , R₂ represents H, CH₃ or CH₃ , H, respectively. Additionally, a copolymer of the diamine compound and method of forming the same are also provided.

Description

Diamine compound, copolymer, and method for forming same

The present invention relates to an amide copolymer and its forming method, in particular to the monomer of diamine compound.

Among the general-purpose plastic materials that have been widely used in various application fields (for example: polyethylene terephthalate, nylon 6, nylon 66, polyethylene, polypropylene, acrylic, polystyrene, polyurethane, Polyvinyl alcohol, etc.), nylon 6 and nylon 66 compared with other general-purpose plastics, the biggest feature is that it has good mechanical strength, toughness, elasticity, wear resistance and other physical properties, so it has been widely used in various blocks Materials, membrane materials, textiles and other fields.

However, nylon 6 and nylon 66 have the disadvantage of high water absorption (the equilibrium water absorption is between 2.5 and 2.8 at a temperature of 25°C and a relative humidity (RH) of 50%). In terms of the application of packaging film materials, although nylon 6 and nylon 66 film materials have better mechanical strength, toughness and wear resistance than other types of polymers, due to their high water absorption rate, the packaging film will lose water after absorbing water. The amorphous region is easy to expand, which reduces the water barrier and gas barrier properties of the packaging film, thereby greatly reducing the original function of the packaging film. In addition, if nylon 6 or nylon 66 is used in applied materials such as parts in high-temperature environments, the application product is prone to hydrolysis due to relatively high water absorption, resulting in a decrease in mechanical strength. In addition, its high water absorption rate is not conducive to the processing process in high humidity environment. Due to this shortcoming, the development of nylon 6 and nylon 66 in many application fields is greatly restricted. Therefore, reducing the water absorption rate of nylon 6 and nylon 66 while maintaining their original melting point and increasing their glass transition temperature is the current method. Important goals in the technical field.

In the previous technology, in order to achieve this goal, the modified polyamide was developed. The design theory of its polymer molecular structure is mainly: the combination of aromatic compounds (such as: terephthalic acid) and nylon 6 and nylon 66 The diamine compounds used are copolymerized together, or the aromatic compounds, diamine compounds, and nylon 6 or nylon 66 monomers are copolymerized together to form aromatic and aliphatic diamine components. Semi-aromatic polyamide copolymer. In addition to greatly reducing the water absorption (generally, the equilibrium water absorption of semi-aromatic polyamide can be lower than 2.0), because of the presence of aromatic components, the glass transition temperature (Tg) of the amide copolymer can be higher than that of the phase Corresponding aliphatic polyamides (generally aliphatic polyamides, such as nylon 6, nylon 66, etc., have a glass transition temperature between about 55-65°C, while semi-aromatic polyamides can be higher than about 90°C) . The increase of glass transition temperature can increase the thermal softening temperature of polyamide, thereby improving the mechanical properties of polyamide application products.

Based on this theory, with reference to literature 1 (S. Cakir et al., Polymer 53 (2012) p.5242-5250), S. Cakir et al. proposed to use 2-methyl-1,5-pentanediamine (2- methyl-1,5-pentanediamine), isophthalate (isophthalate) and caprolactam (caprolactam) three monomers were copolymerized to obtain aromatic group and 2-methyl-1,5-pentane Diamine-based nylon 6 series semi-aromatic polyamide copolymer. Among them, the isophthalic acid group can increase the glass transition temperature of the product and reduce the water absorption rate, and the 2-methyl-1,5-pentanediamine group can improve the glass transition temperature of the polyamide product because it contains a side methyl group. In addition to the conversion temperature, compared with the general linear diamine, the 2-methyl-1,5-pentanediamine group can reduce the chemical structure regularity of polyamide, reduce the crystallinity and melting point temperature of polyamide, and make Polyamides with higher melt viscosity can be processed in a sub-high temperature environment, thereby improving the processability of polyamides.

However, the polymerization process of semi-aromatic polyamides proposed by S. Cakir et al. has obvious disadvantages. Due to the use of three kinds of monomers for random copolymerization, the sequence distribution of aromatic groups in the copolymer is uneven, which makes it difficult to control the physical properties of the product, and the variability of physical properties is large, which is not conducive to Product application development. Therefore, it is necessary to solve the problem of uneven sequence distribution of aromatic groups in the semi-aromatic polyamide copolymer.

(I) 其中R₁ 、R₂ 分別為 H、CH₃ ，或CH₃ 、H。The embodiment of the present invention provides a diamine compound whose chemical structure is shown in formula (I):

(I) wherein R ₁ , R ₂ are H, CH ₃ , or CH ₃ , H, respectively.

(II) 其中R₁ 、R₂ 分別為 H、CH₃ ，或CH₃ 、H，R₃ 為-(CH₂ )_m -，m為2-12的正整數。The embodiment of the present invention provides a kind of copolymer, the chemical structure of its repeating unit is as shown in formula (II):

(II) wherein R ₁ and R ₂ are H, CH ₃ , or CH ₃ , H respectively, R ₃ is -(CH ₂ ) _m -, and m is a positive integer of 2-12.

(I) 其中R₁ 、R₂ 分別為 H、CH₃ ，或CH₃ 、H。An embodiment of the present invention provides a method for forming a diamine compound, comprising: mixing 2-methyl-1,5-pentanediamine and terephthalate to form a mixture; and heating the mixture to react to form a diamine compound ; Wherein, the chemical structure of this diamine compound is as shown in formula (I):

(I) wherein R ₁ , R ₂ are H, CH ₃ , or CH ₃ , H, respectively.

(I) 其中R₁ 、R₂ 分別為 H、CH₃ ，或CH₃ 、H； (iii)混合此二胺化合物與二羧酸，二胺化合物與二羧酸的莫耳比介於1:1.6至1:3.0之間；以及 (iv)在介於200℃至260℃之間的溫度下進行加熱，聚合形成一共聚物，其中此共聚物的重複單元之化學結構如式(II)所示：

(II) 其中R₁ 、R₂ 分別為 H、CH₃ ，或CH₃ 、H，R₃ 為-(CH₂ )_m -，m為2-12的正整數；其中，此共聚物的相對黏度介於2.0至3.5之間。An embodiment of the present invention provides a method for forming a copolymer, including: (i) mixing 2-methyl-1,5-pentanediamine and terephthalate to form a mixture, 2-methyl-1,5-pentane The molar ratio of diamine to terephthalate is between 6:1 and 11:1; (ii) heating the mixture and stirring the reaction 6- In 24 hours, the precipitated solid compound was obtained, and after filtration, the solid diamine compound as shown in formula (I) was obtained, and the chemical structure of the diamine compound was as shown in formula (I):

(I) wherein R ₁ , R ₂ are H, CH ₃ , or CH ₃ , H respectively; (iii) mix the diamine compound and dicarboxylic acid, the molar ratio of diamine compound and dicarboxylic acid is between 1: between 1.6 and 1:3.0; and (iv) heating at a temperature between 200°C and 260°C to polymerize to form a copolymer, wherein the chemical structure of the repeating unit of the copolymer is as shown in formula (II) Show:

(II) wherein R ₁ and R ₂ are H, CH ₃ , or CH ₃ , H respectively, R ₃ is -(CH ₂ ) _m -, m is a positive integer of 2-12; wherein, the relative viscosity of the copolymer Between 2.0 and 3.5.

In the embodiment of the present invention, a diamine compound is formed by first reacting 2-methyl-1,5-pentanediamine and an aromatic monomer (terephthalate), and then making the diamine compound and an aromatic The copolymerization reaction is carried out with the dicarboxylic acid, so that the sequence distribution uniformity of the obtained amide copolymer is improved, the physical property variability of the product is reduced, the water absorption rate is reduced, and the glass transition temperature is increased.

(1) 其中R₁ ;R₂ = H;CH₃ 或CH₃ ;H。In the embodiment (Example 1) of the present invention for preparing diamine compounds, two compounds of terephthalic acid ester and 2-methyl-1,5-pentanediamine are mixed, and the mixture is heated so that 2 -Methyl-1,5-pentanediamine is reacted with terephthalate and combined with a chemical bond to obtain a diamine compound monomer, the chemical structure of which is shown in the following formula (1):

(1) wherein R ₁ ; R ₂ = H; CH ₃ or CH ₃ ; H.

In the example of synthesizing diamine compounds, the temperature of heating the mixture of 2-methyl-1,5-pentanediamine and terephthalate can be between 70°C and 100°C, for example, between 80 °C to 100 °C. If the temperature of the heating mixture is too low (below 80°C), it may cause poor reactivity, resulting in incomplete reaction of the product (for example: only one side of the terephthalate reacts), and requires a longer reaction time. Relatively, if the temperature of the heated mixture is too high (over 100° C.), the reaction product may be cracked and a small amount of by-products may be produced.

On the other hand, in the embodiment of synthesizing diamine compounds, the molar ratio between 2-methyl-1,5-pentanediamine and aromatic monomer (terephthalic acid ester) is preferably between 6:1 to 11:1. If the proportion of 2-methyl-1,5-pentanediamine is too low, it may cause poor reactivity, resulting in incomplete reaction of the product (for example: only one side of the terephthalate reacts). Relatively, if the proportion of 2-methyl-1,5-pentanediamine is too high, the separation and purification of the product will become very difficult.

(2) 其中，R₁ ;R₂ 為H;CH₃ 或CH₃ ;H，R₃ 為-(CH₂ )_m -，m為2-12的正整數。In the embodiment of the present invention for preparing a copolymer, the diamine compound monomer prepared in the foregoing embodiment is mixed with the aromatic dicarboxylic acid monomer and heated to carry out a copolymerization reaction to obtain a compound containing 2-methyl-1, The semi-aromatic polyamide of 5-pentamethylenediamine and aromatic base component, the chemical structure of its repeating unit is as shown in formula (2):

(2) Among them, R ₁ ; R ₂ is H; CH ₃ or CH ₃ ; H, R ₃ is -(CH ₂ ) _m -, m is a positive integer of 2-12.

In one embodiment, the comonomer is heated to a temperature between 200°C and 260°C. If the heating temperature is too low, the formed copolymer may partially solidify or crystallize, resulting in difficulty in stirring. If the heating temperature is too high, amine exchange or even cracking may occur, forming a random copolymer instead of an alternative copolymer.

In one embodiment, the weight molecular weight Mw of the copolymer may be 15,000-25,000 g/mole. The molecular weight of the copolymer can also be represented by relative viscosity (Rv), which is measured according to ASTM D789 standard test method. The relative viscosity of the above-mentioned copolymer may be between 2.0 and 3.5, such as between 2.4 and 3.5. If the relative viscosity of the copolymer is too low, the molecular weight of the copolymer is too low, resulting in poor heat resistance, poor mechanical properties and high brittleness. If the relative viscosity of the copolymer is too high, processing will be difficult.

It is worth noting that, compared with the prior art using three comonomers for copolymerization to obtain random copolymers, the embodiment of the present invention uses two comonomers for copolymerization to obtain interleaved copolymers, so that The sequence distribution uniformity of the obtained copolymer is improved, the variability of physical properties is reduced, the water absorption rate is reduced, and the glass transition temperature is increased.

In addition, the terephthalic acid group in the amide copolymer can increase the melting point, glass transition temperature, heat resistance and reduce water absorption of the copolymer, while the 2-methyl- In addition to increasing the glass transition temperature of polyamide, the 1,5-pentamethylenediamine group can also improve the crystallinity, melting point, and melt viscosity of the amide copolymer due to the use of terephthalic acid groups, and it is not easy to processing problem.

The following examples illustrate the diamine compound, copolymer and preparation method of the present invention in more detail. The following examples are to further illustrate the present invention, but not to limit the scope of the present invention.

In the following examples, the analysis conditions of the relative viscosity (Rv) of the copolymer are based on the ASTM D789 standard test method, but the solvent is changed from formic acid to concentrated sulfuric acid: take 0.50 g of the copolymer and place it in an analysis glass bottle, add concentrated sulfuric acid ( Concentration: 96.0wt%) was configured into a 50ml solution, and then analyzed for relative viscosity (Rv) at 25°C. In addition, the melting point (T _m ) and glass transition temperature (T _g ) of the copolymer were measured with a differential scanning calorimeter. In the following examples, the water absorption of the copolymer is measured according to the ASTM D570 standard test method: the copolymer is weighed after drying at 70°C for 24 hours, then soaked in water at 23°C for 24 hours, taken out, and wiped with general toilet paper Weigh the water on the surface of the copolymer block; calculate the increased water and water absorption rate from the weight after soaking in water minus the weight after drying.

In addition, the chemical components of the diamine compound and the polymer were analyzed with a nuclear magnetic resonance spectrum ( ¹ HNMR) and an infrared spectrometer.

[Example 1]: Synthetic diamine compound

The reaction formula of embodiment 1 is as follows:

200 grams of bis (2-hydroxyethyl) terephthalate (bis (2-hydroxyethyl) terephthalate, BHET), 548 grams of 2-methyl-1,5-pentanediamine (Dy) (BHET : Molar ratio of Dy = 1:6.8), 2 g of Zn(OAc) ₂ (weight ratio of BHET:Zn(OAc) ₂ = 100:1) were added to a 3-liter round bottom bottle, stirred at 90°C React for 24 hours. During the reaction period, the solid was completely dissolved, and the reaction temperature was lowered and allowed to stand for 1 hour (reaction liquid needs to be lowered to room temperature). Then the reaction solution is poured into 4000ml of RO water (20 times the weight of BHET) to produce a precipitate, and then the solid is taken out by centrifugation, and washed with RO water for 6-8 times (using 20-30ml of RO water each time). The solid was dried in a vacuum oven at 80°C to obtain a diamine compound.

After drying, detect and analyze the diamine compound. The diamine compound was measured with a differential scanning calorimeter, and thermal analysis was performed to obtain a melting point (T _m ) of 173.5 °C and a thermal cracking temperature (T _d ) of 389.3 °C. And use nuclear magnetic resonance spectrum and infrared spectrum to analyze the diamine compound, the spectral information obtained is as follows: ¹ HNMR (D ₂ SO ₄ , ppm): δ8.473 (aryl, 8H, s), δ4.061-4.206 (amide NH-CH ₂ , 8H, m), δ3.390-3.581 (terminal NH ₂ -CH ₂ , 4H, m), δ2.259(CH ₂ , 8H, m), δ2.187 (CH ₂ , 4H,m ), δ1.791-1.953 (CH ₃ , 12H, m). From the results of the ¹ HNMR spectrum, it can be calculated that the H number of the benzene ring component/the H number of the aliphatic carbon chain = 8/36, so 2-methyl-1,5-pentanediamine and terephthalate are in diamine compounds The molar ratio in is 2/3, can prove the product structure of embodiment 1 (as shown in formula (I)). IR (cm ^-1 ): 3308 (amine); 1633 (amine, broadband).

In addition, elemental analysis (elemental analysis) was carried out on the diamine compound, and the results 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%).

[Example 2]: Synthetic copolymer, wherein dicarboxylic acid is adipic acid (adipic acid)

其中，R₁ ;R₂ 為H;CH₃ 或CH₃ ;H，R₃ 為-(CH₂ )_m -，m=4。The reaction formula of embodiment 2 is as follows:

Wherein, R ₁ ; R ₂ is H; CH ₃ or CH ₃ ; H, R ₃ is -(CH ₂ ) _m -, m=4.

Mix 610 grams of the diamine compound synthesized in Example 1 with 146 grams of adipic acid (diamine compound: the molar ratio of adipic acid=1:1), add in the steel tank reactor of 2 liters, in 1 hour The temperature was slowly raised from room temperature to 230° C. (the solid was completely melted at 200° C.), and then stirred and reacted at 230° C. for 7 hours. After the reaction, the product was dried in a vacuum oven at 80°C to obtain a copolymer.

After drying, the copolymer was detected and analyzed. The thermal analysis of the copolymer was carried out with a differential scanning calorimeter, and the measured thermal cracking temperature (T _d ), glass transition temperature (T _g ) and melting point (T _m ) are shown in Table 1 below. In addition, the relative viscosity (Rv) was analyzed to be 2.610.

The copolymer was analyzed by nuclear magnetic resonance and infrared spectroscopy, and the obtained spectral information is as follows: ¹ HNMR (D ₂ SO ₄ , ppm): δ8.471 (aryl, 8H, s), δ4.061-4.206 (arylamide NH -CH ₂ , 8H, m), δ3.75-3.85 (aliphatic NH-CH ₂ , 4H, m), δ2.85 (adipic acid moiety -CH ₂ -, adjacent to carboxylate, 4H, m ), δ2.259(CH ₂ , 10H, m), δ2.187 (CH ₂ , 6H,m), δ1.791-1.953 (CH ₃ , 12H, m). IR (cm ^-1 )= 3308 (NH), 1633 (amide, broadband).

[Example 3]: Synthetic copolymer, wherein dicarboxylic acid is sebacic acid (decanedioic acid)

其中，R₁ ;R₂ 為H;CH₃ 或CH₃ ;H，R₃ 為-(CH₂ )_m -，m=8。The reaction formula of embodiment 3 is as follows:

Wherein, R ₁ ; R ₂ is H; CH ₃ or CH ₃ ; H, R ₃ is -(CH ₂ ) _m -, m=8.

Mix 610 grams of the diamine compound synthesized in Example 1 with 202 grams of sebacic acid (the molar ratio of diamine compound: sebacic acid=1:1), add it to a 2-liter steel tank reactor, and mix it with 202 grams of sebacic acid. The temperature was slowly raised from room temperature to 230° C. (the solid was completely melted at 200° C.), and then stirred and reacted at 230° C. for 7 hours. After the reaction, the product was dried in a vacuum oven at 80°C to obtain a copolymer.

After drying, the copolymer was detected and analyzed. The thermal analysis of the copolymer was carried out with a differential scanning calorimeter, and the measured thermal cracking temperature (T _d ), glass transition temperature (T _g ) and melting point (T _m ) are shown in Table 1 below. In addition, the relative viscosity (Rv) was analyzed to be 2.571.

The copolymer was analyzed by nuclear magnetic resonance and infrared spectroscopy, and the obtained spectral information is as follows: ¹ HNMR (D ₂ SO ₄ , ppm): δ8.472 (aryl, 8H, s), δ4.060-4.205 (arylamide NH -CH ₂ , 8H, m), δ3.76-3.85 (aliphatic NH-CH ₂ , 4H, m), δ2.87 (adipic acid moiety -CH ₂ -, adjacent to carboxylate, 4H, m ), δ2.261(CH ₂ , 14H, m), δ2.190 (CH ₂ , 10H, m), δ1.792-1.956 (CH ₃ , 12H, m). IR (cm ^-1 )= 3310 (NH), 1638 (amide, broadband).

[Example 4]: comparative analysis of water absorption

The semi-aromatic polyamide synthesized in Example 2 and Example 3, nylon 66 particles (purchased from DSM Company, relative viscosity Rv=2.690), nylon 6 particles (purchased from DSM Company, relative viscosity Rv=2.621), respectively After being pressed into a sheet under the same conditions, the water absorption was analyzed by the ASTM D570 standard test method, and the results are shown in Table 1 below.

Table 1 Melting point (T _m ) (°C) Glass transition temperature (T _g ) (°C) Water absorption (25℃, 50% RH equilibrium water absorption%) Embodiment 2 (adipic acid system) 244 100 2.0 Example 3 (Sebacic acid series) not obvious 103 1.6 Commodity Nylon 66 255-265 55-65 2.5 Commodity Nylon 6 220-228 55-65 2.8 The semi-aromatic polyamide of Document 1 213-219 not obvious Not reported

It can be seen from Table 1 that the melting point of the amide copolymer in Example 2 of the present invention is between nylon 6 and nylon 66, and higher than that of the copolymer in Document 1. In addition, comparing the glass transition temperature of the amide copolymer synthesized in Example 2 and Example 3 of the present invention with nylon 6 and nylon 66, the glass transition temperature of the amide copolymer in Example 2 and Example 3 is between 100- Between 105°C, which is higher than the glass transition temperature of nylon 6 and nylon 66 (about 55-65°C). Furthermore, comparing the water absorption of the amide copolymer of the embodiment of the present invention with nylon 6 and nylon 66 (at 25°C, the equilibrium water absorption of 50% RH), the water absorption of the amide copolymer of embodiment 2 and embodiment 3 Rates are lower than nylon 6 and nylon 66. This is because, the terephthalic acid group that the amide copolymer of the embodiment of the present invention has can improve the melting point and the glass transition temperature of the amide copolymer, and reduce water absorption, and 2-methyl-1,5- In addition to increasing the glass transition temperature of the amide copolymer, the pentamethylenediamine group can also reduce the high melting point of the amide copolymer due to the use of terephthalic acid groups, and solve the problem that it is not easy to process. That is to say, compared with nylon 6 and nylon 66, the amide copolymer of the embodiment of the present invention can have a melting point that makes the product easy to process and maintain mechanical properties while lowering the water absorption rate, and can increase its glass transition temperature.

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Claims (10)

A kind of diamine compound, its chemical structure is as shown in formula (I):

(I) wherein R ₁ , R ₂ are H, CH ₃ , or CH ₃ , H, respectively. A kind of copolymer, the chemical structure of its repeating unit is as shown in formula (II):

(II) wherein R ₁ and R ₂ are H, CH ₃ , or CH ₃ , H respectively, R ₃ is -(CH ₂ ) _m -, and m is a positive integer of 2-12. The copolymer of claim 2, wherein the relative viscosity (Rv) of the copolymer is between 2.0 and 3.5. A method for forming a diamine compound, comprising: mixing 2-methyl-1,5-pentanediamine and terephthalic acid ester to form a mixture; and heating the mixture to react to form a diamine compound; wherein, the diamine The chemical structure of amine compound is as shown in formula (I):

(I) wherein R ₁ , R ₂ are H, CH ₃ , or CH ₃ , H, respectively. The method for forming a diamine compound according to claim 4, wherein the molar ratio of the 2-methyl-1,5-pentanediamine to the terephthalate is between 6:1 and 11:1. The method for forming a diamine compound according to claim 4, wherein the terephthalate comprises bis(2-hydroxyethyl) terephthalate, dimethyl terephthalate, or a combination thereof. The method for forming a diamine compound according to claim 4, wherein the reaction is stirred for 12-24 hours at a reaction temperature between 70°C and 100°C. A method for forming a copolymer, comprising: (i) mixing 2-methyl-1,5-pentanediamine and terephthalate to form a mixture, the 2-methyl-1,5-pentanediamine and The molar ratio of the terephthalic acid ester is between 6:1 and 11:1; (ii) heating the mixture and stirring the reaction at a reaction temperature between 70°C-100°C for 6-24 hours To form a diamine compound, wherein the chemical structure of the diamine compound is as shown in formula (I):

(I) wherein R ₁ and R ₂ are respectively H, CH ₃ , or CH ₃ , H; (iii) mixing the diamine compound and the dicarboxylic acid, the molar ratio of the diamine compound and the dicarboxylic acid is between Between 1:1.6 and 1:3.0; and (iv) heating at a temperature between 200°C and 260°C to polymerize to form a copolymer, wherein the chemical structure of the repeating unit of the copolymer is as shown in formula (II ) as shown:

(II) wherein R ₁ and R ₂ are respectively H, CH ₃ , or CH ₃ , H, R ₃ is -(CH ₂ ) _m -, m is a positive integer of 2-12; wherein, the relative viscosity of the copolymer Between 2.0 and 3.5. The method for forming the copolymer as claimed in item 8, wherein the chemical structure of the dicarboxylic acid is shown in formula (III):

(III) wherein R ₃ is -(CH ₂ ) _m -, m is a positive integer of 2-12, and R ₄ is H, C1-C4 alkyl, or C1-C4 alkanol group. The method for forming a copolymer according to Claim 9, wherein in the chemical structural formula (III) of the dicarboxylic acid, R ₃ is -(CH ₂ ) _m -, and m is a positive integer of 4-8.