Polyterephthalate-co-sebacate resin as well as preparation method and application thereof

Abstract

The invention relates to polyester terephthalate-co-sebacate resin as well as a preparation method and application thereof, and belongs to the technical field of organic high-molecular compounds. The preparation method of the polyester terephthalate-co-sebacate resin comprises the following steps: S1, mixing a carboxylic acid compound, 1, 4-butanediol, a catalyst, a stabilizer and an inhibitor, and carrying out esterification reaction to obtain an ester; s2, heating the esterified product obtained in the step S1 for pre-polycondensation reaction, and continuously performing final polycondensation reaction to obtain polyester terephthalate-co-sebacate resin; the carboxylic acid compound is a mixture of at least one of terephthalic acid and a terephthalic acid ester derivative and at least one of sebacic acid and a sebacic acid ester derivative; and the inhibitor is 2-methyl-1, 4-butanediol. The preparation method can effectively reduce the yield of the byproduct 2, 5-dihydrofuran.

Description

Technical Field

[0001] The present invention relates to the technical field of organic polymer compounds, and particularly relates to a poly(terephthalate-co-sebacate) resin, a preparation method thereof, and an application thereof. Background Art

[0002] Poly(terephthalate-co-sebacate) resin is a new type of biodegradable material. Since sebacic acid is introduced into the PBT chain segment, it combines the advantages of aliphatic polyesters and aromatic polyesters. It not only has good thermal properties and mechanical properties, but also has excellent ductility and biodegradability. Poly(terephthalate-co-sebacate) resin is generally polymerized from terephthalic acid, 1,4-butanediol, and sebacic acid through a high-temperature esterification reaction. However, in the high-temperature esterification reaction, 1,4-butanediol will undergo a violent side reaction to generate tetrahydrofuran (THF), 2,5-dihydrofuran (2,5-DHF), and water. This side reaction will not only increase the consumption of 1,4-butanediol, but also increase the load on the vacuum system. After the mixture of THF, 2,5-DHF, water, and other gases is extracted and condensed through the vacuum system and collected, it needs to be concentratedly separated and purified through a THF recovery device to meet the emission requirements. Currently, in the prior art, the side reaction of 1,4-butanediol during the high-temperature esterification reaction is mainly reduced or inhibited by adding a specific catalyst (titanium-silicon-cobalt composite catalyst) or a specific inhibitor (4-[(tetrahydro-2-furanyl)oxy]-1-butanol) to reduce the generation of THF. However, in the actual production process, it is found that 2,5-DHF in the by-products will significantly increase the purification difficulty, resulting in an increase in energy consumption and production costs. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a poly(terephthalate-co-sebacate) resin, a preparation method thereof, and an application thereof.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] In the first aspect, the present invention provides a preparation method of a poly(terephthalate-co-sebacate) resin, including the following steps:

[0006] S1. Mix a carboxylic acid compound, 1,4-butanediol, a catalyst, a stabilizer, and an inhibitor to carry out an esterification reaction to obtain an esterified product;

[0007] S2. Heat the esterified product obtained in S1 for a pre-polycondensation reaction, and continue to carry out a final polycondensation reaction to obtain a poly(terephthalate-co-sebacate) resin;

[0008] The carboxylic acid compound is a mixture of at least one of terephthalic acid, terephthalate derivatives and at least one of sebacic acid, sebacate derivatives;

[0009] The inhibitor is 2-methyl-1,4-butanediol (CAS No.: 2938-98-9).

[0010] In the method for preparing the poly(terephthalate-co-sebacate) resin of the present invention, by selecting 2-methyl-1,4-butanediol as the inhibitor to inhibit the side reactions of 1,4-butanediol to generate tetrahydrofuran and 2,5-dihydrofuran during the high-temperature esterification reaction, the yield of 2,5-dihydrofuran can be effectively reduced, thereby reducing the difficulty of separation and purification.

[0011] It should be noted that the present invention does not particularly limit the source of the reaction raw material inhibitor 2-methyl-1,4-butanediol, which can be an impurity existing in 1,4-butanediol or directly added 2-methyl-1,4-butanediol; the inventor found that as long as the chromatographic peak area of the inhibitor / (the chromatographic peak area of the inhibitor + the chromatographic peak area of 1,4-butanediol) meets the range defined by the present invention.

[0012] Optionally, the terephthalate derivative can specifically be at least one of dimethyl terephthalate, diethyl terephthalate, and dibutyl terephthalate; the sebacate derivative can specifically be at least one of dimethyl sebacate, diethyl sebacate, and dibutyl sebacate. The molar ratio of the carboxylic acid compound to 1,4-butanediol is 1: (1.8 - 2).

[0013] As a preferred embodiment of the method for preparing the poly(terephthalate-co-sebacate) resin of the present invention, according to the GB / T24768-2009 standard, based on the chromatographic purity of 1,4-butanediol, in the mixture of 1,4-butanediol and the inhibitor, the chromatographic peak area of the inhibitor is 0.02% - 0.5% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

[0014] Optionally, the chromatographic peak area of the inhibitor / (the chromatographic peak area of the inhibitor + the chromatographic peak area of 1,4-butanediol) can specifically be any one of 0.02%, 0.05%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5% or the range value of any two of them.

[0015] The chromatographic peak area can be calculated by a chromatograph. The specific test method for the chromatographic peak area is: before the S1 esterification reaction, dissolve the inhibitor raw material in the 1,4-butanediol raw material and mix them, and calculate by testing with a gas chromatograph according to the GB / T24768-2009 standard. The integrated area of the chromatographic peak is the chromatographic peak area.

[0016] Among them, the chromatographic peak area of the inhibitor can be controlled by controlling the dosage of the inhibitor, and it is the percentage of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

[0017] As a preferred embodiment of the preparation method of the poly(terephthalate-co-sebacate) resin described in the present invention, the chromatographic peak area of the inhibitor is 0.15% - 0.4% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

[0018] As a preferred embodiment of the preparation method of the poly(terephthalate-co-sebacate) resin described in the present invention, the chromatographic peak area of the inhibitor is 0.25% - 0.35% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

[0019] As a preferred embodiment of the preparation method of the poly(terephthalate-co-sebacate) resin described in the present invention, according to the GB / T24768-2009 standard, the retention time of 1,4-butanediol is 12.6 - 12.8 min, and the retention time of the inhibitor is 13.8 - 14.1 min.

[0020] As a preferred embodiment of the preparation method of the poly(terephthalate-co-sebacate) resin described in the present invention, the esterification reaction in S1 is as follows: the mixed components are heated to 220 - 240 °C under a nitrogen atmosphere, the vacuum degree is 40 - 60 KPa, and the reaction is carried out for 3 - 5 h.

[0021] As a preferred embodiment of the preparation method of the poly(terephthalate-co-sebacate) resin described in the present invention, S2 specifically includes the following steps: the esterified product in S1 is depressurized to below 100 Pa within 30 min, and the reaction is continued at 240 - 260 °C for 2 - 5 h until the intrinsic viscosity reaches 1.0 - 1.6 dL / g, then nitrogen is filled, and extrusion granulation is carried out to obtain the poly(terephthalate-co-sebacate) resin.

[0022] As a preferred embodiment of the preparation method of the poly(terephthalate-co-sebacate) resin described in the present invention, the catalyst in S1 includes at least one of tetrabutyl orthotitanate and tetraisopropyl orthotitanate. In practical applications, the dosage of the catalyst can be 10 - 5000 ppm of the theoretical output weight of the poly(terephthalate-co-sebacate) resin.

[0023] As a preferred embodiment of the preparation method of the poly(terephthalate-co-sebacate) resin described in the present invention, the stabilizer in S1 includes at least one of phosphoric acid, phosphorous acid, triphenyl phosphite, triphenyl phosphate, and sodium phosphite. In practical applications, the dosage of the stabilizer can be 10 - 1000 ppm of the theoretical weight of the poly(terephthalate-co-sebacate) resin.

[0024] Second aspect, the present invention provides a poly(butylene terephthalate-co-sebacate) resin prepared by the above preparation method. Preferably, in terms of molar percentage, the molar content of butylene terephthalate units in the poly(butylene terephthalate-co-sebacate) resin is 45% to 60%, and the molar content of butylene sebacate units is 40% to 55%. The intrinsic viscosity of the poly(butylene terephthalate-co-sebacate) resin is 1.0 to 1.6 dL / g.

[0025] Third aspect, the present invention provides the application of the above poly(butylene terephthalate-co-sebacate) resin in the preparation of film bags.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] In the preparation method of the poly(butylene terephthalate-co-sebacate) resin of the present invention, by selecting 2-methyl-1,4-butanediol as an inhibitor to inhibit the side reactions of 1,4-butanediol generating tetrahydrofuran and 2,5-dihydrofuran during the high-temperature esterification reaction, the yield of 2,5-dihydrofuran can be effectively reduced, and further the difficulty of separation and purification can be reduced. Description of the Drawings

[0028] Figure 1 It is the chromatogram in Example 1. Detailed Embodiments

[0029] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0030] Other materials, reagents, etc. used in the examples and comparative examples can be obtained from commercial channels without special instructions.

[0031] Terephthalic acid, manufacturer: Ineos Zhuhai;

[0032] Sebacic acid, manufacturer: Jinghua Hengshui;

[0033] 1,4-Butanediol, manufacturer: Xinjiang Meike, grade: industrial 1,4-butanediol; According to the GB / T24768-2009 standard, based on the chromatographic purity of 1,4-butanediol, the chromatographic peak area of 2-methyl-1,4-butanediol is 0.01% of the sum of the chromatographic peak areas of 2-methyl-1,4-butanediol and 1,4-butanediol.

[0034] Example 1

[0035] This example provides a preparation method of a poly(butylene terephthalate-co-sebacate) resin, including the following steps:

[0036] S1. Dissolve 30.5 g of inhibitor (2-methyl-1,4-butanediol) in 10.1 kg of 1,4-butanediol to obtain an inhibitor / 1,4-butanediol solution;

[0037] Add the inhibitor / 1,4-butanediol solution, 5.123 kg of terephthalic acid, 5.1 kg of sebacic acid, 14 g of catalyst (tetrabutyl orthotitanate), and 5 g of stabilizer (phosphoric acid) into a reaction kettle and mix them. After purging with nitrogen, heat up to 225 ± 2 °C, and control the vacuum in the reaction kettle at 50 ± 2 KPa. After reacting for 3.0 - 3.5 h, an esterified product is obtained;

[0038] S2. Reduce the pressure in the reaction kettle to below 100 Pa within 30 min, and continue to react at 245 ± 2 °C for 3.5 - 4.0 h. When the intrinsic viscosity reaches 1.5 dL / g, charge nitrogen and extrude and pelletize to obtain poly(terephthalate-co-sebacate) resin.

[0039] Among them, the molar ratio of the total amount of terephthalic acid and sebacic acid to 1,4-butanediol is 1:2, and the molar ratio of terephthalic acid to sebacic acid is 55:45.

[0040] According to the GB / T24768-2009 standard, the chromatographic peak area of the inhibitor and the chromatographic peak area of 1,4-butanediol are obtained through a chromatograph; among them, the chromatographic conditions are: the sample to be measured is a mixed solution of 1,4-butanediol (BDO) and the inhibitor (i.e., the inhibitor / 1,4-butanediol solution in step S1). The initial temperature of the chromatograph is 60 °C, keep it for 1 - 2 min and then increase the temperature at a rate of 10 °C / min to 260 °C. The carrier gas flow rate is 5 mL / min, the chromatographic column is Agilent 123-1334UL, the carrier gas is nitrogen, the injection volume is 0.2 - 0.5 μL, the vaporization chamber temperature is 300 °C, the detector temperature is 300 °C, and the retention time is 30 min to obtain a chromatogram as Figure 1 shown.

[0041] According to Figure 1 it can be known that the chromatographic peak with a larger area is the chromatographic peak area of 1,4-butanediol, the retention time is 12.8 min, and the peak area is 560323970; the chromatographic peak with a smaller area is the chromatographic peak area of the inhibitor (2-methyl-1,4-butanediol), the retention time is 13.9 min, and the peak area is 1686030. The chromatographic peak area of the inhibitor / (the chromatographic peak area of the inhibitor + the chromatographic peak area of 1,4-butanediol) = 1686030 / (1686030 + 560323970) = 0.3%; the retention time of 1,4-butanediol is 12.6 - 12.8 min, and the retention time of the inhibitor is 13.8 - 14.1 min.

[0042] Example 2

[0043] This example provides a method for preparing a poly(terephthalate-co-sebacate) resin, which is basically the same as Example 1, except that the dosage of the inhibitor is different. According to the GB / T 24768-2009 standard, based on the chromatographic purity of 1,4-butanediol, the chromatographic peak area of the inhibitor is 0.02% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

[0044] Example 3

[0045] This example provides a method for preparing a poly(terephthalate-co-sebacate) resin, which is basically the same as Example 1, except that the dosage of the inhibitor is different. According to the GB / T 24768-2009 standard, based on the chromatographic purity of 1,4-butanediol, the chromatographic peak area of the inhibitor is 0.15% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

[0046] Example 4

[0047] This example provides a method for preparing a poly(terephthalate-co-sebacate) resin, which is basically the same as Example 1, except that the dosage of the inhibitor is different. According to the GB / T 24768-2009 standard, based on the chromatographic purity of 1,4-butanediol, the chromatographic peak area of the inhibitor is 0.25% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

[0048] Example 5

[0049] This example provides a method for preparing a poly(terephthalate-co-sebacate) resin, which is basically the same as Example 1, except that the dosage of the inhibitor is different. According to the GB / T 24768-2009 standard, based on the chromatographic purity of 1,4-butanediol, the chromatographic peak area of the inhibitor is 0.35% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

[0050] Example 6

[0051] This example provides a method for preparing a poly(terephthalate-co-sebacate) resin, which is basically the same as Example 1, except that the dosage of the inhibitor is different. According to the GB / T 24768-2009 standard, based on the chromatographic purity of 1,4-butanediol, the chromatographic peak area of the inhibitor is 0.4% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

[0052] Example 7

[0053] This example provides a method for preparing poly(terephthalate-co-sebacate) resin, which is basically the same as Example 1, except that the dosage of the inhibitor is different. According to the GB / T 24768-2009 standard, based on the chromatographic purity of 1,4-butanediol, the chromatographic peak area of the inhibitor is 0.5% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

[0054] Example 8

[0055] This example provides a method for preparing poly(terephthalate-co-sebacate) resin, comprising the following steps:

[0056] S1. Dissolve 11.9 g of the inhibitor (2-methyl-1,4-butanediol) in 3.9 kg of 1,4-butanediol to obtain an inhibitor / 1,4-butanediol solution;

[0057] Add the inhibitor / 1,4-butanediol solution, 2.0 kg of terephthalic acid, 2.43 kg of sebacic acid, 3.5 g of the catalyst (tetraisopropyl orthotitanate), and 2.5 g of the stabilizer (phosphorous acid) into a reaction kettle for mixing. After purging with nitrogen, heat up to 230 ± 2 °C, and control the vacuum in the reaction kettle at 55 ± 2 KPa. After reacting for 3.0 - 3.5 h, an esterified product is obtained;

[0058] S2. Reduce the pressure in the reaction kettle to below 50 Pa within 30 min, and continue to react at 250 ± 2 °C for 2.5 - 3.0 h. When the intrinsic viscosity reaches 1.05 dL / g, charge nitrogen and extrude and pelletize to obtain poly(terephthalate-co-sebacate) resin.

[0059] Among them, the molar ratio of the total amount of terephthalic acid and sebacic acid to 1,4-butanediol is 1:1.8, and the molar ratio of terephthalic acid to sebacic acid is 1:1.

[0060] According to the GB / T 24768-2009 standard, based on the chromatographic purity of 1,4-butanediol, the chromatographic peak area of the inhibitor is 0.3% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

[0061] Comparative Example 1

[0062] This comparative example provides a method for preparing poly(terephthalate-co-sebacate) resin, which is basically the same as Example 1, except that the dosage of the inhibitor is 0 (i.e., no inhibitor is added). At this time, the chromatographic peak area of 2-methyl-1,4-butanediol is 0.01% of the sum of the chromatographic peak areas of 2-methyl-1,4-butanediol and 1,4-butanediol, and 2-methyl-1,4-butanediol is derived from the impurities in 1,4-butanediol.

[0063] Comparative Example 2

[0064] This comparative example provides a method for preparing a poly(terephthalate-co-sebacate) resin, which is basically the same as that of Example 1, except that the dosage of the inhibitor is different. According to the GB / T 24768-2009 standard, based on the chromatographic purity of 1,4-butanediol, the chromatographic peak area of the inhibitor is 1% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

[0065] Comparative Example 3

[0066] This comparative example provides a method for preparing a poly(terephthalate-co-sebacate) resin, which maintains the chromatographic peak area of the inhibitor at 0.3% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol as in Example 1, except that the type of the inhibitor is different. The inhibitor is 4-[(tetrahydro-2-furanyl)oxy]-1-butanol.

[0067] Performance Test

[0068] Take the esterification water condensed and collected by the vacuum system during the esterification reaction (esterification reaction start ≥ 10 min) of each example and comparative example as the test sample, and according to the GB 24772-2009 standard, obtain the chromatographic peak area of 2,5-DHF and the chromatographic peak area of THF through a chromatograph. The yield (%) of 2,5-DHF = chromatographic peak area of 2,5-DHF / chromatographic peak area of THF × 100%.

[0069] The specific test method includes the following steps: The initial temperature of the chromatograph (manufacturer Agilent, model 7820A) is 40 °C, and after maintaining for 5 - 10 min, it is heated at a heating rate of 8 °C / min to 165 °C, maintained for 2 min, and then heated at a heating rate of 15 °C / min to 240 °C, maintained for 8 min; the carrier gas flow rate is 1.5 mL / min, the chromatographic column is Agilent 123-1334UL, the carrier gas is nitrogen, the injection volume is 0.2 - 0.5 μL, the vaporization chamber temperature is 250 °C, the detector temperature is 250 °C, and the retention time is 35 min. The retention time of 2,5-DHF is 9.4 - 9.7 min, and the retention time of THF is 10.0 - 10.3 min.

[0070] Table 1 Yields of 2,5-dihydrofuran in each example and comparative example

[0071]

[0072]

[0073] According to the data in Table 1, the yields of 2,5-dihydrofuran in Examples 1-8 are all ≤ 2%, indicating that the preparation method of the poly(terephthalate-co-sebacate) resin of the present invention can effectively reduce the yield of the by-product 2,5-dihydrofuran. At the same time, it can be seen from Comparative Examples 1 and 2 that when the content of the inhibitor is too small, it is difficult to effectively inhibit the formation of 2,5-dihydrofuran; while when the addition amount of the inhibitor is too large, since the reaction of the inhibitor is a reversible reaction, it instead leads to a weakening of the inhibitory effect on the formation of 2,5-dihydrofuran, resulting in a relatively high yield of 2,5-dihydrofuran. In addition, it can be found from Comparative Example 3 that when 4-[(tetrahydro-2-furanyl)oxy]-1-butanol is used as the inhibitor, it is difficult to effectively reduce the generation of 2,5-dihydrofuran.

[0074] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a poly(terephthalate-co-sebacate) resin, characterized in that, It includes the following steps: S1. Mix a carboxylic acid compound, 1,4-butanediol, a catalyst, a stabilizer, and an inhibitor to carry out an esterification reaction to obtain an esterified product; S2. Heat up the esterified product obtained in S1 for a pre-polycondensation reaction and continue with a final polycondensation reaction to obtain a poly(terephthalate-co-sebacate) resin; The carboxylic acid compound is a mixture of at least one of terephthalic acid, terephthalate derivatives and at least one of sebacic acid, sebacate derivatives; The inhibitor is 2-methyl-1,4-butanediol.

2. The preparation method according to claim 1, wherein According to the GB / T24768-2009 standard, based on the chromatographic purity of 1,4-butanediol, the chromatographic peak area of the inhibitor is 0.02% - 0.5% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

3. The preparation method according to claim 2, wherein, The chromatographic peak area of the inhibitor is 0.15% - 0.4% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

4. The preparation method according to claim 3, wherein, The chromatographic peak area of the inhibitor is 0.25% - 0.35% of the sum of the chromatographic peak areas of the inhibitor and 1,4-butanediol.

5. The preparation method according to claim 1, characterized in that, The esterification reaction in S1 is as follows: Heat up the mixed components to 220 - 240°C under a nitrogen atmosphere with a vacuum degree of 40 - 60 KPa and react for 3 - 5 h.

6. The preparation method according to claim 1, characterized in that, S2 specifically includes the following steps: Reduce the pressure of the esterified product obtained in S1 to below 100 Pa within 30 min, continue to react at 240 - 260°C for 2 - 5 h until the intrinsic viscosity reaches 1.0 - 1.6 dL / g, fill in nitrogen, extrude and pelletize to obtain a poly(terephthalate-co-sebacate) resin.

7. The preparation method according to claim 1, characterized in that, The catalyst in S1 includes at least one of tetrabutyl orthotitanate and tetraisopropyl orthotitanate.

8. The preparation method according to claim 1, characterized in that, The stabilizer in S1 includes at least one of phosphoric acid, phosphorous acid, triphenyl phosphite, triphenyl phosphate, and sodium phosphite.

9. A poly(terephthalate-co-sebacate) resin prepared by the preparation method according to any one of claims 1 - 8.

10. Use of the poly(terephthalate-co-sebacate) resin according to claim 9 in the preparation of film bags.

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