CN115260480A - Refining method of poly (methyl ethylene carbonate-phthalate) - Google Patents
Refining method of poly (methyl ethylene carbonate-phthalate) Download PDFInfo
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- CN115260480A CN115260480A CN202210889825.8A CN202210889825A CN115260480A CN 115260480 A CN115260480 A CN 115260480A CN 202210889825 A CN202210889825 A CN 202210889825A CN 115260480 A CN115260480 A CN 115260480A
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- phthalate
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G64/00—Macromolecular compounds obtained by reactions forming a carbonic ester link in the main chain of the macromolecule
- C08G64/40—Post-polymerisation treatment
- C08G64/406—Purifying; Drying
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Abstract
The invention discloses a method for refining poly (methyl ethylene carbonate-phthalate), which comprises the steps of mixing hot water with a colloidal crude product, changing the crude product into a solid state, evaporating a large amount of propylene oxide and recovering, washing the crude product on a conveyor belt by using cold water to cool and shape, refining, separating and removing most of water, and drying to obtain high-purity poly (methyl ethylene carbonate-phthalate). The refining process of the invention is provided with a refining procedure at the same time, so that the product can be refined into powder or granules to meet the requirements of downstream application. And various separated substances can be recycled in the refining process, so that the environmental protection problem is solved. The refining method provided by the invention has the advantages that the adopted equipment is simple, and the refining method can be connected with production equipment to form a complete industrial production line, so that the cost is reduced and the production efficiency is improved.
Description
Technical Field
The invention belongs to the technical field of degradable plastics, and particularly relates to a refining method of poly (methyl ethylene carbonate-phthalate).
Background
The PPC plastic is also called polymethyl ethylene carbonate, is a transparent, completely degradable and environment-friendly plastic synthesized by taking carbon dioxide and propylene oxide as raw materials, has excellent biocompatibility, high barrier property and impact toughness, and has the elongation at break of 600-1200 percent. But its low glass transition temperature (Tg =30-40 ℃) limits its large scale application.
The invention patent of China with the patent number ZL 202010337273.0 discloses a preparation method of a biodegradable carbon dioxide-based polyester-polycarbonate terpolymer, which comprises the steps of introducing phthalic anhydride, propylene oxide, tetra-n-butyl ammonium chloride and triethylboron solution in an anhydrous and anaerobic environment, filling carbon dioxide into a high-pressure reaction kettle, and reacting at 80 ℃ to obtain poly (methyl ethylene carbonate-phthalate), namely PPC-P. Phthalic anhydride is a cheap and easily available raw material, and the patent utilizes the ternary copolymerization reaction of propylene oxide, carbon dioxide and phthalic anhydride to introduce an aromatic polyester structure with the content of 10-40% into a PPC main chain by a one-step one-pot method to obtain poly (methyl ethylene carbonate-phthalic acid ester), thereby not only improving the thermal property of the PPC material, but also having high light transmittance, good biodegradability and foaming property.
The obtained poly (methyl ethylene carbonate-phthalate) is a novel biodegradable plastic, has good mechanical and thermal properties, and can be used for manufacturing disposable tableware, disposable medical materials, packaging materials, agricultural mulching films and the like.
At present, because poly (methyl ethylene carbonate-phthalate) is put into industrial production for the first time, no matched product refining process exists. Because of the particularity of the product, the crude product directly obtained by the reaction contains propylene oxide raw material and other byproducts (such as cyclic carbonate, propylene glycol, dibutyl ether and other byproducts), and is in a liquid state at a high temperature, and the requirements of the conventional common refining process are difficult to meet. In addition, the method and equipment adopted by the existing refining process are difficult to be matched with the preparation process of the poly (methyl ethylene carbonate-phthalate) to form a complete production line, so that the cost is reduced and the efficiency is improved.
Disclosure of Invention
In order to solve the above problems, an object of the present invention is to provide a method for purifying a poly (methyl ethylene carbonate-phthalate) having a high purity, which solves the problem that a product is in a gel state at a high temperature while a propylene oxide raw material and a by-product (a by-product such as cyclic carbonate, propylene glycol, dibutyl ether, etc.) are entrained in a production process of the poly (methyl ethylene carbonate-phthalate).
In order to achieve the purpose, the invention adopts the technical scheme that:
a method for refining poly (methyl ethylene carbonate-phthalate), which comprises the following steps:
(1) Conveying the crude product in the glue state of poly (methyl ethylene carbonate-phthalate) into a washing device, continuously blowing hot water into the washing device, mixing the hot water with the crude product in the glue state, quickly evaporating propylene oxide carried by the crude product after the contact with the hot water, and recovering a gas phase to a propylene oxide rectifying tower for further refining and recovery;
(2) The crude product is changed from a glue liquid state to a solid state, and is separated from hot water in a washing device and output to a conveyor belt, the hot water is recycled, and a small amount of propylene oxide and byproducts in the crude product are recovered through evaporation after multiple times of cyclic enrichment;
(3) Further cooling and shaping the solid crude product on a conveyor belt by using cold water, and recycling the cold water;
(4) The washed product enters a thinning procedure and is thinned into powder or granules according to the requirement;
(5) Most of moisture is removed from the refined product through separation, and then the refined product enters a drying link to remove the residual moisture, so that a high-purity poly (methyl ethylene carbonate-phthalate) product is obtained.
Preferably, in the above method for purifying poly (methyl ethylene carbonate-phthalate), the hot water temperature in the step (1) is 60 to 95 ℃.
Preferably, in the above method for purifying poly (methyl ethylene carbonate-phthalate), the gas phase recovery method in the step (1) is atmospheric evaporation or reduced pressure evaporation.
Preferably, in the above method for purifying poly (methyl ethylene carbonate-phthalate), the evaporation in step (2) is single-effect evaporation, double-effect evaporation, triple-effect evaporation or MVR evaporation.
Preferably, in the above method for purifying poly (methyl ethylene carbonate-phthalate), the cold water in the step (3) is 5 to 20 ℃ and the cold water is used by spraying or dipping.
Preferably, in the above method for purifying poly (methyl ethylene carbonate-phthalate), the refining in step (4) is strand cutting, extrusion granulation, crushing or pulverization.
Preferably, in the above method for purifying poly (methyl ethylene carbonate-phthalate), the separation in the step (5) is decantation, centrifugation, filtration or gravity settling.
Preferably, in the above method for purifying poly (methyl ethylene carbonate-phthalate), the drying in step (5) is normal pressure drying, reduced pressure drying, vacuum drying, hot air drying, cold air drying or fluidized bed drying.
Compared with the prior art, the invention has the following beneficial effects: the crude product of poly (methyl ethylene carbonate-phthalate) is in a liquid state, has high temperature and can carry propylene oxide raw materials and byproducts such as cyclic carbonate, propylene glycol, dibutyl ether and the like. The conventional purification methods of the compounds are all methods such as reduced pressure concentration, extraction washing or recrystallization. However, these methods are not suitable for the purification of the target product of the present invention. The invention provides a method for refining poly (methyl ethylene carbonate-phthalate) through a large number of experiments for the first time, which comprises the steps of mixing hot water with a colloidal crude product, changing the crude product into a solid state, evaporating a large amount of propylene oxide and recovering, washing the crude product on a conveyor belt by using cold water to cool and shape, refining, separating and removing most of water, and drying to obtain high-purity poly (methyl ethylene carbonate-phthalate). The refining process of the invention is provided with a refining procedure at the same time, which can refine the product into powder or granules and meet the requirements of downstream application. And various separated substances can be recycled in the refining process, so that the environmental protection problem is solved. The refining method provided by the invention has the advantages that the adopted equipment is simple, and the refining method can be connected with production equipment to form a complete industrial production line, so that the cost is reduced and the production efficiency is improved.
Detailed Description
Preparation of crude poly (methyl ethylene carbonate-phthalate):
a50 mL high-pressure reaction kettle is used as a reaction vessel, 1.0g of phthalic anhydride, 3.92g of propylene oxide, 7.5mg of tetra-n-butylammonium chloride and 54 mu L of triethylboron solution are sequentially added into the high-pressure reaction kettle in an anhydrous oxygen-free environment, 1.0MPa of carbon dioxide is filled, the reaction is carried out for 12 hours at the temperature of 80 ℃, the pressure of the carbon dioxide is released after the reaction is finished, dichloromethane is used for dissolving the product, the reaction is quenched by dilute hydrochloric acid/methanol solution, and the product is precipitated in ethanol to obtain a crude poly (methyl ethylene carbonate-phthalate) (the purity is about 50%).
Example 1:
conveying the poly (methyl ethylene carbonate-phthalate) crude product into a washing device at the speed of 24 kg/h, continuously blowing hot water at 90 ℃, mixing the hot water with the crude product in a glue liquid state, changing the crude product from the glue liquid state into a solid state, separating the solid product from the hot water in the washing device, and outputting the solid product onto a conveying belt. And (3) spraying and cooling the upper part of the conveying belt by using cold water at the temperature of 5 ℃, conveying the cooled product to a crusher to be refined into powder, dewatering the powder in a horizontal centrifuge, and drying in a vacuum dryer to obtain a light yellow or white transparent poly (methyl ethylene carbonate-phthalate) product, wherein the purity reaches 99.5% through measurement and calculation.
Example 2:
conveying the poly (methyl ethylene carbonate-phthalate) crude product into a washing device at the speed of 25 kg/h, continuously blowing hot water with the temperature of 85 ℃, mixing the hot water with the crude product in a glue liquid state, changing the crude product from the glue liquid state into a solid state, separating the solid state from the hot water in the washing device, and outputting the solid state onto a conveying belt. Soaking the rear part of the conveying belt in cold water of 15 ℃, conveying the cooled product to an extrusion granulator to be refined into granules, dewatering the granules in a horizontal centrifuge, and drying the granules in a vacuum dryer to obtain a light yellow or white transparent poly (methyl ethylene carbonate-phthalate) product, wherein the purity of the product reaches 99.8 percent through measurement and calculation.
Example 3:
conveying the poly (methyl ethylene carbonate-phthalate) crude product into a washing device at the speed of 20 kg/h, continuously blowing hot water at 80 ℃, mixing the hot water with the crude product in a glue liquid state, changing the crude product from the glue liquid state into a solid state, separating the solid product from the hot water in the washing device, and outputting the solid product onto a conveying belt. And (3) spraying and cooling the upper part of the conveying belt by using cold water at the temperature of 8 ℃, conveying the cooled product to a crusher to be refined into powder, dewatering the granular materials in a screen centrifuge, and drying in a vacuum dryer to obtain a light yellow or white transparent poly (methyl ethylene carbonate-phthalate) product, wherein the purity reaches 99.5 percent through measurement and calculation.
Example 4:
conveying the poly (methyl ethylene carbonate-phthalate) crude product into a washing device at the speed of 12 kg/h, continuously blowing hot water at 82 ℃, mixing the hot water with the crude product in a glue liquid state, changing the crude product from the glue liquid state into a solid state, separating the solid state from the hot water in the washing device, and outputting the solid state onto a conveying belt. And (3) spraying and cooling the upper part of the conveying belt by using cold water at the temperature of 5 ℃, conveying the cooled product to a crusher to be refined into powder, dewatering the granular material in a horizontal centrifuge, and drying in an oven to obtain a light yellow or white transparent poly (methyl ethylene carbonate-phthalate) product, wherein the purity is up to 99.1% by calculation.
Example 5:
conveying the poly (methyl ethylene carbonate-phthalate) crude product into a washing device at the speed of 24 kg/h, continuously blowing hot water at 90 ℃, mixing the hot water with the crude product in a glue liquid state, changing the crude product from the glue liquid state into a solid state, separating the solid product from the hot water in the washing device, and outputting the solid product onto a conveying belt. And (3) spraying and cooling the upper part of the conveying belt by using cold water at the temperature of 5 ℃, conveying the cooled product to a crusher to be refined into powder, dewatering the granular material in a horizontal centrifuge, drying the granular material in a vibrating fluidized bed to obtain a light yellow or white transparent poly (methyl ethylene carbonate-phthalate) product, and measuring and calculating to obtain the product with the purity of 99.2%.
Comparative example 1:
and refining the crude poly (methyl ethylene carbonate-phthalate) by adopting a reduced pressure concentration method, wherein the purity of the obtained poly (methyl ethylene carbonate-phthalate) is 75%, and the catalyst and byproducts are carried in the product and are not effectively recycled.
Comparative example 2:
and (3) refining the crude poly (methyl ethylene carbonate-phthalate) by an extraction washing method, wherein the purity of the obtained poly (methyl ethylene carbonate-phthalate) is 84%, and the product is not entrained with a catalyst but is entrained with most of byproducts which are not effectively recycled.
Comparative example 3:
and (2) refining the crude poly (methyl ethylene carbonate-phthalate) product by adopting a recrystallization method, wherein the purity of the obtained poly (methyl ethylene carbonate-phthalate) is 88 percent, no catalyst is carried in the product, but a small part of by-products are carried in the product, and the small part of by-products are not effectively recycled.
Comparative example 4: (crude PPC product was purified by the method of example 1)
The crude PPC product (purity about 46%) was fed into a washing apparatus at a rate of 24 kg/h, and hot water at 90 ℃ was continuously blown into the washing apparatus, and the hot water was mixed with the crude product in the form of a gum, and the crude product was changed from the gum into a solid form and separated from the hot water in the washing apparatus, and then discharged onto a conveyor belt. And (3) cooling the upper part of the conveying belt by using cold water at 5 ℃, conveying the cooled product to a crusher to be refined into powder, dewatering the powder in a horizontal centrifuge, and drying in a vacuum dryer to obtain a light yellow or white transparent PPC product, wherein the purity is up to 78% according to measurement, all catalysts and byproducts are carried in the product, and the byproducts are not effectively recycled.
Claims (8)
1. A method for purifying poly (methyl ethylene carbonate-phthalate), which is characterized by comprising the following steps:
(1) Conveying the crude product of the poly (methyl ethylene carbonate-phthalate) glue into a washing device, continuously blowing hot water into the washing device, mixing the hot water with the crude product of the glue, quickly evaporating propylene oxide carried by the crude product after the propylene oxide is contacted with the hot water, and recovering a gas phase to a propylene oxide rectifying tower for further refining and recovery;
(2) The crude product is changed from a glue liquid state to a solid state, and is separated from hot water in a washing device and output to a conveyor belt, the hot water is recycled, and a small amount of propylene oxide and byproducts in the crude product are recovered through evaporation after multiple times of cyclic enrichment;
(3) Further cooling and shaping the solid crude product on a conveyor belt by using cold water, and recycling the cold water;
(4) The washed product enters a thinning procedure and is thinned into powder or granules according to the requirement;
(5) Most of moisture is removed from the refined product through separation, and then the refined product enters a drying link to remove residual moisture, so that a high-purity poly (methyl ethylene carbonate-phthalate) product is obtained.
2. The method for purifying poly (methyl ethylene carbonate-phthalate) according to claim 1, wherein the temperature of the hot water in the step (1) is 60 to 95 ℃.
3. The method for purifying poly (methyl ethylene carbonate-phthalate) according to claim 1, wherein the gas phase recovery in step (1) is atmospheric evaporation or vacuum evaporation.
4. The method for purifying poly (methyl ethylene carbonate-phthalate) according to claim 1, wherein the evaporation in step (2) is single-effect evaporation, double-effect evaporation, triple-effect evaporation or MVR evaporation.
5. The method for purifying poly (methyl ethylene carbonate-phthalate) according to claim 1, wherein the cold water in the step (3) is 5 to 20 ℃ and the cold water is used by spraying or dipping.
6. The method for purifying poly (methyl ethylene carbonate-phthalate) according to claim 1, wherein the refining in step (4) is strand cutting, extrusion granulation, crushing or pulverization.
7. The method for purifying poly (methyl ethylene carbonate-phthalate) according to claim 1, wherein the separation in the step (5) is decantation, centrifugation, filtration or gravity settling.
8. The method for purifying poly (methyl ethylene carbonate-phthalate) according to claim 1, wherein the drying in the step (5) is atmospheric drying, reduced pressure drying, vacuum drying, hot air drying, cold air drying or fluidized bed drying.
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| CN202210889825.8A CN115260480A (en) | 2022-07-27 | 2022-07-27 | Refining method of poly (methyl ethylene carbonate-phthalate) |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111378101A (en) * | 2020-04-26 | 2020-07-07 | 中山大学 | Preparation method of biodegradable carbon dioxide-based polyester-polycarbonate terpolymer |
| CN112898551A (en) * | 2021-03-11 | 2021-06-04 | 中山大学 | Post-production treatment device and method for semi-aromatic polyester-polycarbonate copolymer |
| CN112898552A (en) * | 2021-03-11 | 2021-06-04 | 中山大学 | Condensation devolatilization device and method for semi-aromatic polyester-polycarbonate copolymer |
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- 2022-07-27 CN CN202210889825.8A patent/CN115260480A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111378101A (en) * | 2020-04-26 | 2020-07-07 | 中山大学 | Preparation method of biodegradable carbon dioxide-based polyester-polycarbonate terpolymer |
| CN112898551A (en) * | 2021-03-11 | 2021-06-04 | 中山大学 | Post-production treatment device and method for semi-aromatic polyester-polycarbonate copolymer |
| CN112898552A (en) * | 2021-03-11 | 2021-06-04 | 中山大学 | Condensation devolatilization device and method for semi-aromatic polyester-polycarbonate copolymer |
Non-Patent Citations (1)
| Title |
|---|
| 宋鹏飞等: "二氧化碳/环氧丙烷/邻苯二甲酸酐三元共聚物的合成及性能", 高分子材料科学与工程, vol. 25, no. 8, pages 1 - 4 * |
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