Semi-continuous production method of active controllable polyester

Abstract

The invention discloses a semi-continuous production method of active controllable polyester. The method comprises the following steps: adding an alcohol material and an acid material into a batching kettle, adding a boron-containing auxiliary agent, heating, mixing, conveying the mixed material to a premixing kettle for premixing, and inputting the material into a reaction kettle after premixing reaction; and adding small-molecular alcohol and a catalyst into the reaction kettle, heating and carrying out esterification polycondensation to obtain the target polyester. According to the assistant and the process method, the polyester activity can be regulated and controlled, the hydrolysis resistance of the catalyst is enhanced, the polyester production period is shortened, and generation of by-products and color development substances is reduced, so that the stability of a polyester product is improved, the color number of the polyester product is reduced, and more possibilities are provided for downstream application of the polyester.

Description

Technical Field

[0001] The present invention relates to the field of polymer material synthesis, and particularly relates to a semi - continuous production method of living - controlled polyester. Background Art

[0002] Polyester polyol is one of the earliest industrialized polymers in the application process of the polyurethane industry. With the emergence of polyether polyols, due to the price advantage of polyether polyols, the application of polyether polyols has rapidly exceeded that of traditional polyester polyols. Although polyether polyols have developed rapidly, as a kind of materials with excellent properties in polyurethane materials, polyester polyols have excellent mechanical properties, outstanding oil - resistance, chemical - resistance and other characteristics, and are still an extremely important type of polyurethane at present.

[0003] Generally, two synthetic routes are used to produce polyester. One is through the polycondensation reaction of diol and diacid, and the other is the ring - opening polymerization reaction of lactone or lactide. The polycondensation reaction generally includes two steps: esterification and polycondensation. In the esterification stage, the diol and diacid undergo an esterification reaction under self - catalyzed conditions to generate an esterification product with a relatively small molecular weight. Subsequently, it enters the polycondensation stage. A catalyst is added, and under high - temperature and high - vacuum conditions, the materials undergo transesterification reactions, connecting with each other to remove small - molecule substances from the system, and finally obtaining a polyester with a large molecular weight. A polyester product with a specified molecular weight can be obtained by controlling the polymerization time. The second route starts from lactone or lactide, undergoes ring - opening, and then under the action of a catalyst, the monomers undergo chain growth based on an initiator to obtain a high - molecular - weight polyester product.

[0004] At the present stage, in order to shorten the production cycle, catalysts need to be added during the synthesis of polyester. Currently, the most widely used catalysts that can catalyze the polymerization of polyester are mainly some organometallic catalysts. Commonly used ones include antimony, titanium, germanium, tin - based catalysts. Especially, titanium - based catalysts are widely used due to their good catalytic effect. However, these catalysts are not resistant to hydrolysis, and the addition amount required to shorten the production cycle is relatively high. The metal ions remaining in these catalysts in the polyester product make the polyester highly active during downstream applications, affecting the shaping, demolding and other properties of downstream products. At the same time, these catalysts themselves will show oxidation and color - development phenomena under high - temperature environments, which will affect the color number of the polyester and cause quality problems in polyester products.

[0005] In summary, in the polyester production process, in order to shorten the production cycle, the addition amount of the catalyst needs to be increased, but the large amount of catalyst added makes the produced polyester have a high color number and high activity, reducing the quality of the polyester. Summary of the Invention

[0006] Aiming at the problems existing in the prior art, one of the purposes of the present invention is to provide a semi - continuous production method of living - controlled polyester. The polyester produced by this method has a low color number and controlled activity due to its low catalyst content.

[0007] The method is different from the existing batch production process, but proposes a semi - continuous production process, changing the original one - kettle production to three - kettle semi - continuous production; at the same time, the boron - containing additive is first premixed and reacted with the raw materials, and then a small amount of catalyst is added and polymerized with small - molecule alcohol to obtain a polyester product with a low catalyst content. The boron - containing additive used in the present invention reduces the use of titanium - based catalysts, reduces the generation of by - products, lowers the product color number, and also makes the product activity controllable.

[0008] To achieve the above - mentioned invention purpose, the present invention adopts the following specific technical solutions:

[0009] A semi - continuous production method of living - controlled polyester, the method comprising the following steps:

[0010] S1: Add alcohol and acid materials to a batching kettle, add a boron - containing additive, raise the temperature, mix, and convey the mixed materials to a premixing kettle for premixing. After the premixing reaction, the materials are input into a reaction kettle;

[0011] S2: Add small - molecule alcohol and a catalyst into the reaction kettle, raise the temperature for esterification polycondensation to obtain the target polyester.

[0012] In an embodiment of the present invention, the alcohol in S1 is a diol, preferably one or more of ethylene glycol, 1,4 - butanediol, 1,3 - butanediol, 1,3 - propanediol, 1,2 - propanediol, neopentyl glycol, 1,5 - pentanediol, 1,2 - hexanediol, 2,5 - hexanediol, 1,6 - hexanediol, octanediol.

[0013] In an embodiment of the present invention, the acid in S1 is a dicarboxylic acid and / or a dicarboxylic anhydride, preferably one or more of malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phenylmalonic acid, phthalic anhydride, biphenyl anhydride, 2,3 - dimethyl maleic anhydride, 2 - methyl succinic anhydride, maleic anhydride, more preferably one or more of malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid; preferably, the molar ratio of the alcohol to the acid = 1:(0.1 - 2).

[0014] In one embodiment of the present invention, the boron-containing auxiliary agent in S1 is an organic boron-amine complex, preferably one or more of pyridine borane complex, morpholine borane complex, benzylamine borane complex, ethylenediamine borane complex, N,N-diethylaniline borane complex, triethylboron propylamine complex, trimethylboron diethylamine complex, triethylboron butylamine complex, isobutylboron dibutylamine complex; preferably, the mass fraction of the boron-containing auxiliary agent in the total feed is 10-1000 ppm.

[0015] In one embodiment of the present invention, the temperature for heating up in S1 is 100-150 °C.

[0016] In one embodiment of the present invention, the temperature for premixing in S1 is 80-220 °C, and the time is 1-10 h.

[0017] In one embodiment of the present invention, the small molecule alcohol in S2 is a C2-C8 diol, preferably one or more of ethylene glycol, 1,4-butanediol, 1,3-butanediol, 1,3-propanediol, 1,2-propanediol, neopentyl glycol, 1,5-pentanediol, 1,2-hexanediol, 2,5-hexanediol, 1,6-hexanediol, octanediol; preferably, the molar ratio of the acid to the small molecule alcohol is 1:(0.01-1).

[0018] In one embodiment of the present invention, the catalyst in S2 is a titanate catalyst, preferably one or more of methyl phthalate, tetrapropyl titanate, tetrabutyl titanate, tetraisopropyl titanate, tetraoctyl titanate; preferably, the mass fraction of the catalyst in the total feed is 5-100 ppm.

[0019] In one embodiment of the present invention, the temperature for heating up in S2 is 180-250 °C, and the total time is 5-20 h; preferably, the heating up is a stepwise programmed heating.

[0020] Another object of the present invention is to provide a polyester.

[0021] A polyester prepared by the above method, the polyester has a uniform color number and ≤30 APHA, controllable activity, the reaction phase time with -NCO groups can be adjusted between 5-300 s, the acid value is less than 0.3 mg KOH / g of the sample, and the molecular weight is controllable between 800-6000.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The prepared polyester product has a low color number, controllable activity and high stability.

[0024] (2) The introduced additives can promote the reaction process, shorten the production cycle, reduce the by-products caused by titanium catalysts, and improve the hydrolysis resistance of the catalyst, ensuring better catalytic effects. Description of the Drawings

[0025] Figure 1 is a schematic diagram of polyester produced by a semi-continuous process in a molten state;

[0026] Figure 2 is a schematic diagram of polyester produced by a semi-continuous process after solidification. Detailed Embodiments

[0027] The following are some examples to further illustrate the content of the present invention patent, but the present invention patent is not limited to these examples.

[0028] Raw material information: adipic acid, 99%; succinic acid, 99%; suberic acid, 99%; 1,4-butanediol, 99%; ethylene glycol, 99%; 1,3-propanediol; tetra-isopropyl titanate, 98%; tetra-n-butyl titanate, 98%; tetra-propyl titanate, 98%; phthalic anhydride, 99%; Beijing Innochem Technology Co., Ltd., Innochem. Neopentyl glycol, 99%; borane-ethylenediamine complex, 97%; triethylboron butylamine complex, 97%; trimethylboron diethylamine, 97%; diethylaniline borane complex, 97%; Aladdin.

[0029] Equipment information: gel permeation chromatograph (GPC), Agilent 1260 Infinity II; potentiometric titrator, 905 Titrando.

[0030] Acid value titration standard: GB / T7304-2014.

[0031] Example 1

[0032] In a batching kettle, 146.14 adipic acid was mixed with 90.12 g of 1,4-butanediol, 0.005 g of borane-ethylenediamine complex was added, the temperature of the system was raised to 120 °C and stirred until evenly mixed, and the mixture was transferred to a premixing kettle for premixing reaction. Then the temperature was raised to maintain the system temperature at 150 °C for 5 h.

[0033] The system was transferred into a reaction kettle, 16.22 g of 1,4-butanediol and 0.0076 g of tetra-n-butyl titanate were added. First, the temperature was raised to 180 °C for a constant-temperature reaction for 1 h, then the temperature was raised to 220 °C for a constant-temperature reaction for 2 h. After the constant-temperature reaction was completed, the system was evacuated to 10 kPa for polycondensation reaction. After 6 h of reaction, the material was taken out to obtain a polyester sample S1 with controllable activity.

[0034] The acid value of the polyester product was determined by chemical titration, the molecular weight distribution of the sample was detected by GPC, and the color of the product was compared by color standards.

[0035] Example 2

[0036] In a batching kettle, 118.09 g of succinic acid and 18 g of 1,4-butanediol were mixed, 0.148 g of triethylboron butylamine complex was added, the temperature of the system was raised to 150 °C and stirred to mix evenly, and the mixture was transferred to a premixing kettle for premixing reaction. Then the temperature was raised to keep the system temperature at 170 °C and reacted for 9 h.

[0037] The system was transferred into a reaction kettle, 62 g of ethylene glycol and 0.0023 g of tetra-isopropyl titanate were added. First, the temperature was raised to 180 °C and kept at a constant temperature for 1 h, then the temperature was raised to 200 °C and kept at a constant temperature for 10 h. After the constant temperature ended, the system was evacuated to 10 kPa for polycondensation reaction. After reacting for 7 h, the material was taken out to obtain a polyester sample S2 with controllable activity.

[0038] The acid value of the polyester product was determined by chemical titration, the molecular weight distribution of the sample was detected by GPC, and the color of the product was compared by color standards.

[0039] Example 3

[0040] In a batching kettle, 174.2 g of suberic acid and 124 g of ethylene glycol were mixed, 0.03 g of trimethylboron diethylamine complex was added, the temperature of the system was raised to 130 °C and stirred to mix evenly, and the mixture was transferred to a premixing kettle for premixing reaction. Then the temperature was raised to keep the system temperature at 150 °C and reacted for 1.5 h.

[0041] The system was transferred into a reaction kettle, 3 g of ethylene glycol and 0.03 g of tetra-propyl titanate were added. First, the temperature was raised to 200 °C and kept at a constant temperature for 1 h, then the temperature was raised to 220 °C and kept at a constant temperature for 2 h. After the constant temperature ended, the system was evacuated to 10 kPa for polycondensation reaction. After reacting for 3 h, the material was taken out to obtain a polyester sample S3.

[0042] The acid value of the polyester product was determined by chemical titration, the molecular weight distribution of the sample was detected by GPC, and the color of the product was compared by color standards.

[0043] Example 4

[0044] In a batching kettle, 146.14 g of adipic acid and 45 g of 1,4-butanediol were mixed, 0.038 g of diethylaniline borane complex was added, the temperature of the system was raised to 150 °C and stirred to mix evenly, and the mixture was transferred to a premixing kettle for premixing reaction. Then the temperature was raised to keep the system temperature at 180 °C and reacted for 5 h.

[0045] Charge the system into a reactor, add 78 g of neopentyl glycol and 0.013 g of tetraisopropyl titanate. First, heat up to 200 °C and keep the temperature constant for 2 h, then heat up to 220 °C and keep the temperature constant for 2 h. After the constant temperature is over, evacuate the system to 10 kPa and carry out polycondensation reaction. After reacting for 5 h, take out the material to obtain a polyester sample S4 with controllable activity.

[0046] Determine the acid value of the polyester product by chemical titration, detect the molecular weight distribution of the sample by GPC, and compare the product colority through color standards.

[0047] Example 5

[0048] Mix 148.12 g of phthalic anhydride and 114.15 g of 1,3-propanediol in a batching kettle, add 0.16 g of borane-ethylenediamine complex, heat up the system to 150 °C and stir to mix evenly. Charge the mixture into a premixing kettle for premixing reaction, and then heat up to keep the system temperature at 220 °C for 2 h.

[0049] Charge the system into a reactor, add 2 g of 1,3-propanediol and 0.004 g of tetrabutyl titanate. First, heat up to 230 °C and keep the temperature constant for 2 h, then heat up to 250 °C and keep the temperature constant for 3 h. After the constant temperature is over, evacuate the system to 10 kPa and carry out polycondensation reaction. After reacting for 3 h, take out the material to obtain a polyester sample S5 with controllable activity.

[0050] Determine the acid value of the polyester product by chemical titration, detect the molecular weight distribution of the sample by GPC, and compare the product colority through color standards.

[0051] Comparative Example 1

[0052] Compared with Example 1, the difference is that no boron-containing additive is added, and others are the same.

[0053] Mix 146.14 adipic acid and 90.12 g of 1,4-butanediol in a batching kettle, heat up the system to 120 °C and stir to mix evenly. Charge the mixture into a premixing kettle for premixing reaction, and then heat up to keep the system temperature at 150 °C for 5 h.

[0054] Charge the system into a reactor, add 16.22 g of 1,4-butanediol and 0.0076 g of tetrabutyl titanate. First, heat up to 180 °C and keep the temperature constant for 1 h, then heat up to 220 °C and keep the temperature constant for 2 h. After the constant temperature is over, evacuate the system to 10 kPa and carry out polycondensation reaction. After reacting for 6 h, take out the material to obtain a polyester sample D1.

[0055] Determine the acid value of the polyester product by chemical titration, detect the molecular weight distribution of the sample by GPC, and compare the product colority through color standards.

[0056] Comparative Example 2

[0057] Compared with Example 1, the difference is that the semi - continuous process is not adopted, and others are the same.

[0058] 146.14 g of adipic acid, 106.34 g of 1,4 - butanediol, 0.005 g of borane - ethylenediamine complex and 0.0076 g of tetra - isopropyl titanate were heated and mixed. The system was heated to 120 °C and stirred until evenly mixed, and then heated to maintain the system temperature at 150 °C for 5 h.

[0059] The reaction kettle was heated to 180 °C and kept at a constant temperature for 1 h, then heated to 220 °C and kept at a constant temperature for 2 h. After the constant - temperature stage ended, the system was evacuated to 10 kPa for polycondensation reaction. After 6 h of reaction, the material was taken out to obtain polyester sample D2.

[0060] The acid value of the polyester product was determined by chemical titration, the molecular weight distribution of the sample was detected by GPC, and the color of the product was compared by color standards.

[0061] Comparative Example 3

[0062] Compared with Example 1, the difference is that the boron - containing additive is not added and the semi - continuous process is not adopted, and others are the same.

[0063] 146.14 g of adipic acid, 106.34 g of 1,4 - butanediol and 0.0076 g of tetra - isopropyl titanate were heated and mixed. The system was heated to 120 °C and stirred until evenly mixed, and then heated to maintain the system temperature at 150 °C for 5 h.

[0064] The reaction kettle was heated to 180 °C and kept at a constant temperature for 1 h, then heated to 220 °C and kept at a constant temperature for 2 h. After the constant - temperature stage ended, the system was evacuated to 10 kPa for polycondensation reaction. After 6 h of reaction, the material was taken out to obtain polyester sample D3.

[0065] The acid value of the polyester product was determined by chemical titration, the molecular weight distribution of the sample was detected by GPC, and the color of the product was compared by color standards.

[0066] Comparative Example 4

[0067] Compared with Example 1, the difference is that the boron - containing additive is not added, and some catalysts are added to replace the boron - containing additive, and others are the same. The results show that the added catalysts do not play the role of replacing the boron - containing additive.

[0068] 146.14 g of adipic acid and 90.12 g of 1,4 - butanediol were mixed in the batching kettle. The system was heated to 120 °C and stirred until evenly mixed, and then the mixture was transferred to the premixing kettle for premixing reaction. Then it was heated to maintain the system temperature at 150 °C for 5 h.

[0069] The system was charged into a reaction kettle, 16.22 g of 1,4-butanediol and 0.076 g of tetra-n-butyl titanate were added. First, the temperature was raised to 180 °C and kept constant for 1 h, then the temperature was raised to 220 °C and kept constant for 2 h. After the constant temperature ended, the system was evacuated to 10 kPa for polycondensation reaction. After 6 h of reaction, the material was taken out to obtain polyester sample D4.

[0070] The acid value of the polyester product was determined by chemical titration, the molecular weight distribution of the sample was detected by GPC, and the colority of the product was compared with the colority standard.

[0071] The experimental data and analysis results of each sample are shown in the following table:

[0072]

Claims

1. A semi - continuous production method of living - controlled polyester, characterized in that, the method comprises the following steps: S1: Add alcohol and acid materials into a batching kettle, add a boron - containing auxiliary agent, raise the temperature, mix, convey the mixed materials to a premixing kettle for premixing. After the premixing reaction, the materials are input into a reaction kettle; S2: Add a small - molecule alcohol and a catalyst into the reaction kettle, raise the temperature for esterification polycondensation to obtain the target polyester.

2. The method according to claim 1, characterized in that, the alcohol in S1 is a diol, preferably one or more of ethylene glycol, 1,4 - butanediol, 1,3 - butanediol, 1,3 - propanediol, 1,2 - propanediol, neopentyl glycol, 1,5 - pentanediol, 1,2 - hexanediol, 2,5 - hexanediol, 1,6 - hexanediol, octanediol; and / or, the acid in S1 is a dibasic acid and / or a dibasic anhydride, preferably one or more of malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phenylmalonic acid, phthalic anhydride, biphenyl anhydride, 2,3 - dimethyl maleic anhydride, 2 - methyl succinic anhydride, maleic anhydride, more preferably one or more of malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid; Preferably, the molar ratio of the acid to the alcohol = 1:(0.1 - 2); and / or, the boron - containing auxiliary agent in S1 is an organic boron - amine complex, preferably one or more of borane pyridine complex, borane morpholine complex, benzylamine borane complex, borane ethylenediamine complex, N,N - diethylaniline borane complex, triethylboron propylamine complex, trimethylboron diethylamine complex, triethylboron butylamine complex, isobutylboron dibutylamine complex; Preferably, the mass fraction of the boron - containing auxiliary agent in the total feed is 10 - 1000 ppm.

3. The method according to claim 1 or 2, characterized in that, the temperature for raising the temperature in S1 is 100 - 150 °C; and / or, the temperature for premixing in S1 is 150 - 220 °C, and the time is 1 - 10 h.

4. The method according to claim 1, characterized in that, the small - molecule alcohol in S2 is a C2 - C8 diol, preferably one or more of ethylene glycol, 1,4 - butanediol, 1,3 - butanediol, 1,3 - propanediol, 1,2 - propanediol, neopentyl glycol, 1,5 - pentanediol, 1,2 - hexanediol, 2,5 - hexanediol, 1,6 - hexanediol, octanediol; Preferably, the molar ratio of the acid to the small - molecule alcohol is 1:(0.01 - 1); and / or, the catalyst in S2 is a titanate - type catalyst, preferably one or more of methyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetra - isopropyl titanate, tetra - octyl titanate; Preferably, the mass fraction of the catalyst in the total feed is 5 - 100 ppm; and / or, the temperature for raising the temperature in S2 is 180 - 250 °C, and the total time is 5 - 20 h; Preferably, the temperature - raising is a stage - program temperature - raising.

5. A polyester prepared by the method according to any one of claims 1 - 4, characterized in that, The polyester has a uniform color number and ≤ 30 APHA, with controllable activity. The reaction phase time with the -NCO group can be regulated between 5 - 300 s, the acid value is less than 0.3 mg KOH / g of the sample, and the molecular weight can be controlled between 800 - 6000.

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