KR20160092600A - Oil extraction methods of polymer resin using supercritical carbon dioxide from the co-Extrusion of a polymer resin and Oil - Google Patents

Abstract

The present invention relates to a method to divide oil and a high polymer in a co-extrusion of a high polymer resin. The method is able to obtain a benefit in excluding a usage of an organic solvent which seriously affects the environment and is harmful to the human body, and excludes an installation of a costly solvent reprocessing facility for an organic solvent extracting process and a leakage prevention facility by manufacturing a separation film by dividing oil via a supercritical carbon dioxide in a process to manufacture a lithium ion battery separation film via co-extrusion of a polyolefin based resin and oil; and benefits in the prevention of a dangerous environmental damage facing the exposure of a solvent. In addition, the method is able to obtain an additional benefit to collect the divided oil by simply reducing a pressure of carbon dioxide without reprocessing the solvent. Moreover, the method has an additional benefit by reusing the division and reusing the oil and resin for process loss wasted after unexpected extrusion. The method dissolves the oil using the supercritical carbon dioxide, and uses a method to divide the oil and the carbon dioxide by decompressing the supercritical carbon dioxide in which the oil is dissolved.

Description

TECHNICAL FIELD The present invention relates to a method of separating oil and a polymer resin from supercritical carbon dioxide in a pneumatic depression of a polymer resin and an oil,

The present invention relates to a method for separating polymer resin and oil in co-extrusion of polyolefin polymer resin and oil which have been used for various purposes including the production process of wet separation membrane for lithium ion battery, and a method using supercritical carbon dioxide extraction / RTI >

Solids, liquids, gases, etc. are classified into different properties when the temperature and pressure are changed to a certain level or less. When the liquid is properly filled in a high-pressure vessel and heated, the temperature and pressure increase. In this process, the density of the liquid decreases and the density of the gas increases. The temperature and pressure at which the two states of liquid and gas can not be distinguished from each other are called critical points. Supercritical fluid refers to a fluid that is above the critical temperature and above the critical pressure. The gas at a temperature higher than the critical temperature is not liquefied even when pressure is applied.

Continuously applying pressure on such a gas in a high-pressure vessel does not become a liquid, but the density becomes close to the liquid. Generally, the solubility, which is the ability to dissolve a substance, is proportional to the density of the solvent, so supercritical fluids have a considerable solubility when the pressure is high enough. However, in the supercritical state, the distance between the molecules is not as close as the liquid, and the viscosity, diffusion coefficient, thermal conductivity, and surface tension are similar to the gas. That is, supercritical fluids have high solubility, fast diffusion rate, and fast penetration into the micro space due to low surface tension.

When a gaseous substance at room temperature is selected as a supercritical fluid, the problem of residual solvent can be solved. Particularly when carbon dioxide (CO2) is used as a solvent, it is possible to develop a non-toxic, environment- It is widely used because it can extract high purity of materials, natural fragrance, food materials and cosmetic materials.

This patent relates to a method for separating polymer resin and oil from pneumatic effluent of oil and polymer resin by utilizing supercritical carbon dioxide instead of solid, liquid or gas.

The first commercialization of supercritical fluid technology is the removal of caffeine from coffee beans as a solvent in supercritical CO2. Supercritical CO2 dissolves nonpolar materials with low molecular weight such as caffeine, but peptides of polarity that are related to coffee aroma are limited to dissolve, leaving the aroma intact in the coffee and removing caffeine.

In addition, supercritical fluid technology extracts the active ingredient from the fruit of the hop that makes the bitter taste of the beer. In addition, it extracts hundreds of kinds of natural fragrance, cosmetic ingredients, food additive, health food. In recent years, technologies that are harmless to the human body and the environment have been developed using CO2 as a dry cleaning solvent. DuPont of the United States produces high quality products using supercritical CO2 as a solvent for manufacturing Teflon.

Since the establishment of a critical sesame oil manufacturing company in 2002 for the purpose of supercritical process and food business in Korea, the world's first CO2-based supercritical fluid technology has been used for 2 years and 6 months to produce sesame oil from sesame seeds And succeeded in commercializing the factory. Since the beginning of 2005, the supercritical sesame oil extraction plant located in Hyungkoungkung Chungbuk Province has produced 7 tons of sesame oil per day.

Professor Yoon Woo Lee of the Supercritical Fluid Process Laboratory, Department of Chemical and Biological Engineering, Seoul National University, revised the Food Code (the Korea Food and Drug Administration revised notification 2004 -41), research on supercritical extraction processes, and support for commercialization.

Here, we will examine various application technologies using supercritical fluid. In the food industry, toxic solvents such as methylene chloride, which is widely used in the liquid solvent extraction, remain. However, when the supercritical solvent is used, such problems are solved, and glyceride and cooking oil can be classified into various components. Since the supercritical CO2 has a very good solubility and its extraction rate is about 2.5 times, the application fields are very diverse.

Caffeine Extraction from Coffee

In 1987, supercritical fluid technology emerged in West Germany by constructing a plant that uses CO2 to remove caffeine from coffee. In this process, CO2 is continually circulated and caffeine is extracted. When coffee beans containing much moisture are placed in the extraction tower and passed through CO2 at 16~22 MPa at 90 ℃, caffeine is diffused into CO2.

After the extracted caffeine is washed with water in the washing tower, the washing water and caffeine are separated from the CO2 in the deaeration tank and the water and caffeine are separated from each other in the distillation tower. By this process, the caffeine content of 0.7 ~ 3% contained in the coffee bean can be reduced to 0.02% or less.

Nicotine extraction from tobacco

Supercritical carbon dioxide removes nicotine that is harmful to the human body contained in cigarettes while minimizing the loss of aroma. This process consists of a three-step process. The first step is to selectively extract the aroma by supercritical CO2. The aroma is first injected into a nicotine and aroma-removed cigarette in a batch, Supply, remove nicotine. In the third stage, the supercritical CO2 expands and the aroma is evenly dispersed in the cigarette. In this case, about 94.7% of the initial nicotine concentration can be eliminated.

Edible oil extraction

When extracting oil such as triglyceride from soybean or corn, the phosphorous compound can obtain low oil compared to extraction with conventional nucleic acid. 36% vanillin was extracted from soybeans using supercritical CO2, which is very high compared to the extraction concentration of 20% when using water-soluble ethanol as a solvent, and the extraction yield is also good at 97%. Moreover, since the extraction temperature is also near room temperature, the taste and fragrance can be maintained.

Fish oil separation

When used in medicine, it is mainly used for the separation and purification of an active ingredient having a medicinal or physiological activity in a raw material. For example, EPA, DHA, and the like are polyunsaturated fatty acids having 20 and 22 carbon atoms, and are physiologically active substances that are abundantly contained in sardines and the like.

Γ-linolenic acid in the evening primrose oil is a substance that regulates human physiological function. When the extraction method using supercritical CO2 is used, it is more stable than the conventional separation methods such as compression method, steam distillation method and solvent extraction method, I can drive.

Chemical industry, energy field

In the case of separating materials by conventional separation methods such as distillation, the energy cost has risen more than 10 times compared to the past 80s, so energy-saving processes have attracted attention. Among them, many research and development Is underway. On the other hand, there are many applications such as purification of a synthetic polymer material and removal of residual monomers, and removal of odor by use of ethylene or methane as the odorous resin.

The most widely used method for regenerating activated carbon is the thermal regeneration method, which requires a lot of energy because it is operated at a high temperature. Also, even if regeneration is performed in an inert atmosphere, oxidation of activated carbon occurs and loss is 5 to 10% by abrasion.

Chemical industry

In order to be competitive in the chemical industry, it is necessary to obtain fine chemical products and high value-added products rather than to mass-produce general chemicals. Demand for fine chemical products and high purity compounds is increasing every year in Korea. Therefore, it is important to isolate isomeric compounds used as basic raw materials or intermediates in a wide range of fields such as fine chemicals, pharmaceuticals, pesticides, and polymers.

Benefits of supercritical fluid utilization technology

When supercritical fluid is used, the solute component can be selectively extracted by changing the temperature and pressure.

There is also a problem of high initial capital such as equipment investment due to high-voltage operation, but there is an advantage that the thermo-denatured material can be safely separated at low temperatures. In addition, non-toxic fluids can be used to purify medicines and foods without pollution. Solvents used in conventional solvent extraction must be purified through distillation, etc., but supercritical solvents can be easily recovered by changing temperature or pressure There is one advantage.

A polyolefin resin and a diluent (a low molecular weight organic material having a molecular structure similar to that of a polyolefin) are kneaded at a high temperature at which the polyolefin resin is melted during the manufacturing process of the battery separator to produce a single phase, And a wet preparation method in which the diluent portion is extracted to form a void inside. The wet method is a method of imparting mechanical strength and transparency through a stretching / extraction process after a phase separation process. The film is thin and uniform in thickness, uniform in pore size, and has excellent physical properties compared to other manufacturing methods, Which is widely used in the manufacture of a semiconductor device.

With the full use of the secondary battery and the high performance, the use of the separation membrane produced by the wet process has been expanded. In addition, efforts have been continuously made to improve the productivity and film properties of the microporous film by the wet process. As a typical method, the ultrahigh molecular weight polyolefin (UHMWPO) having a weight average molecular weight of about 1,000,000 is used or mixed to increase the molecular weight of the composition and to increase the strength of the porous membrane by introducing a stretching process.

In this connection, U.S. Patent No. 5,051,183, U.S. Patent No. 5,830,554, U.S. Patent No. 6,245,272 and U.S. Patent No. 6,566,012 disclose a composition comprising a polyolefin having a weight average molecular weight of 500,000 or more and a polyolefin A solvent is used to prepare a sheet, and thereafter a sequential drawing process and a solvent extraction process are performed to produce a microporous membrane.

The diluent used herein may be any organic compound that forms a single phase with the polyolefin resin used in the resin composition at the extrusion temperature. Examples include aliphatic or cyclic hydrocarbons such as nonane, decane, decalin, paraffin oil, paraffin wax, and dibutyl phthalate phthalic acid esters such as phthalate and dioctyl phthalate and fatty acids between 10 and 20 carbon atoms such as palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, and palmitic acid alcohols, Fatty alcohols having 10 to 20 carbon atoms such as alcohols and oleic acid alcohols, and mixtures thereof. The sheet is formed through kneading / extrusion of the diluent and the polyolefin resin, followed by stretching to form a film, then the internal diluent is extracted using an organic solvent, and the film is dried. As the organic solvent to be used, methyl ethyl ketone, methylene chloride, hexane and the like which have high extraction efficiency and fast drying are used. Methods such as an immersion method, a solvent spray method, and an ultrasonic method have been proposed and used for the extraction method. However, the solvent used here is harmful to the human body and seriously affects the environment. The equipment for extraction needs to be an expensive leaking prevention facility, and its operating cost also contributes to the product unit price. In addition, there is a risk of causing environmental damage when leaking in case of emergency. Also, the reprocessing cost of the solvent used also requires significant operating costs.

In order to solve the above problems, the inventors of the present invention have succeeded in securing environmental safety by applying the oil extraction method using the super-hypoxic carbon dioxide extraction method, and there is no need for facility cost and operation cost of the leakage prevention facility It is possible to easily recover the illut.

In the wet separator manufacturing process, the polyolefin resin and the diluent are kneaded to form a single phase, and the formed single-phase mixture passes through the die after the extrusion process to produce a sheet-like extrudate, The phase separation between the resin and the diluent progresses to form an isolated pore. The isolated pore thus formed is filled with a diluent. The pore-forming sheet thus obtained obtains physical properties such as the required film thickness and tensile strength while being subjected to a biaxial stretching process, and the individual pores formed together with the pore-forming sheet form an inter-penetrated pore. Inter-penetrated pores are still filled with diluent, and a master roll is prepared by winding a 500 to 8,000 m stretched film on the core. The core wound with the film is moved to a supercritical carbon dioxide extraction chamber Extraction of oil is carried out using a supercritical carbon dioxide extraction process.

The supercritical extraction chamber has a volume and shape that can be inserted into the core without the film being damaged. This chamber has a CO2 storage tank, a pump, a heater, an extraction chamber, a control valve, a seperator, a control valve, a filter, a chiller Which is contained in a system loop for carbon dioxide extraction and is used in the extraction process.

 In the extraction process, the core is placed in the extraction chamber and the chamber is sealed. After sealing, pressurize the carbon dioxide into the chamber using the pump in the CO2 storage tank. The pressure is controlled by 20 to 500 bar, 40 to 200 bar for more efficient extraction. The pressure is regulated on the basis of the carbon dioxide pressure which is heated through the heater and maintained in the extraction chamber with the heating jacket or heating device. At this time, the temperature of the outlet chamber is recommended to be 20 ~ 120 ℃, and for more efficient extraction, 30 ~ 100 ℃ is recommended. The pressure is controlled through the control valve. The flow rate is maintained at 0.2 ~ 100 kg / min and more efficiently at 0.5 ~ 25 kg / min.

In this case, in the extraction chamber, 0.1 to 20 mol% of the diluent is maintained in the dissolved and dispersed state in the carbon dioxide, and the fluid in the combination of the carbon dioxide and the diluent is decompressed through the control valve and phase- After the extraction process, the extraction chamber is pressurized to atmospheric pressure, and the liquid is separated from the CO2 storage tank by the control valve and filter. The film which is decompressed and wound on the core is again subjected to a heat-fixing process through a roll-to-roll process. In the heat setting process, the film is heat set to remove residual stress and reduce the shrinkage of the final film. In the heat-setting process, the film to be shrunk is forced by holding the heat to remove the residual stress, and the shrinkage and permeability are influenced by the heat-setting temperature and the fixed ratio. When the heat fixing temperature is high, the stress of the resin is lowered and the shrinkage rate is decreased. When the heat fixing temperature is too high, the film is partially melted and the formed micropores are clogged to decrease the permeability. Preferably, the heat-setting temperature is selected within a temperature range in which 5 to 50% by weight of the crystalline portion of the film is melted. If the heat fixing temperature is selected in a temperature range lower than the temperature at which 5 wt% of the crystalline portion of the film is melted, the reorientation of the polyolefin molecules in the film is insufficient and the residual stress of the film is not removed. If the temperature is higher than the melting temperature of 50 wt%, the micropores are blocked by partial melting, and the permeability is lowered. In addition, when the heat is fixed, the tenter type equipment is used to fix the heat stepwise, thereby improving the mechanical properties such as tensile strength and puncture strength, and reducing the shrinkage rate. In the first step in the heat setting process, the transverse direction is elongated by 20 to 100% to increase the transmittance and improve the tensile strength and the puncture strength. The film that has undergone the heat setting process is wound to complete the process of forming the product characteristics.

By separating oil through supercritical carbon dioxide extraction process in the manufacturing process of lithium ion battery separator by coextrusion of polyolefin resin and oil, the use of organic solvent harmful to the human body and seriously affecting the environment is excluded The effect of eliminating the installation of expensive solvent reprocessing facility and leakage prevention facility for the organic solvent extraction process and the effect of preventing the risk of environmental damage that may be encountered in case of leakage of solvent in case of emergency Can be obtained. Further, the oil recovered by the simple decompression of carbon dioxide can be recovered without reprocessing from the solvent, and this additional effect can be obtained. In addition, there was additional effect through oil sorting, recycling, and resin recycling for unexpected process losses to be discarded after extrusion.

[A] Carbon dioxide Reservoir: Storage of liquid CO2
[B] Pump: Pressurization of carbon dioxide
[C, E, G, J] Valve
[D] Heater: Heating of carbon dioxide
[F] Extractor: Structure that can consist of two or more chambers and can be continuous process
[H, K] Control valve: Maintain with setting pressure
[I] Seperator: separation of decompressed carbon dioxide and extract
[L] Chiller: liquefied through cooling of carbon dioxide

The supercritical extraction chamber has a volume and shape that can be inserted into the core without the film being damaged. This chamber has a CO2 storage tank, a pump, a heater, an extraction chamber, a control valve, a seperator, a control valve, a filter, a chiller Which is contained in a system loop for carbon dioxide extraction and is used in the extraction process.

 In the extraction process, the core is placed in the extraction chamber and the chamber is sealed. CO2 storage after sealing

The pump in the tank pressurizes the carbon dioxide into the chamber. The pressure is controlled by 20 to 500 bar, 40 to 200 bar for more efficient extraction. The pressure is regulated on the basis of the carbon dioxide pressure which is heated through the heater and maintained in the extraction chamber with the heating jacket or heating device. At this time, the temperature of the outlet chamber is recommended to be 20 ~ 120 ℃, and for more efficient extraction, 30 ~ 100 ℃ is recommended. The pressure is controlled through the control valve. The flow rate is maintained at 0.2 ~ 100 kg / min and more efficiently at 0.5 ~ 25 kg / min.

In this case, in the extraction chamber, 0.1 to 20 mol% of the diluent is maintained in the dissolved and dispersed state in the carbon dioxide, and the fluid in the combination of the carbon dioxide and the diluent is decompressed through the control valve and phase- After the extraction process, the extraction chamber is pressurized to atmospheric pressure, and the liquid is separated from the CO2 storage tank by the control valve and filter. The film which is decompressed and wound on the core is again subjected to a heat-fixing process through a roll-to-roll process. In the heat setting process, the film is heat set to remove residual stress and reduce the shrinkage of the final film. In the heat-setting process, the film to be shrunk is forced by holding the heat to remove the residual stress, and the shrinkage and permeability are influenced by the heat-setting temperature and the fixed ratio. When the heat fixing temperature is high, the stress of the resin is lowered and the shrinkage rate is decreased. When the heat fixing temperature is too high, the film is partially melted and the formed micropores are clogged to decrease the permeability. Preferably, the heat-setting temperature is selected within a temperature range in which 5 to 50% by weight of the crystalline portion of the film is melted. If the heat fixing temperature is selected in a temperature range lower than the temperature at which 5 wt% of the crystalline portion of the film is melted, the reorientation of the polyolefin molecules in the film is insufficient and the residual stress of the film is not removed. If the temperature is higher than the melting temperature of 50 wt%, the micropores are blocked by partial melting, and the permeability is lowered. In addition, when the heat is fixed, the tenter type equipment is used to fix the heat stepwise, thereby improving the mechanical properties such as tensile strength and puncture strength, and reducing the shrinkage rate. In the first step in the heat setting process, the transverse direction is elongated by 20 to 100% to increase the transmittance and improve the tensile strength and the puncture strength. The film that has undergone the heat setting process is wound to complete the process of forming the product characteristics.

[A] Carbon dioxide Reservoir: Storage of liquid CO2
[B] Pump: Pressurization of carbon dioxide
[C, E, G, J] Valve
[D] Heater: Heating of carbon dioxide
[F] Extractor: Structure that can consist of two or more chambers and can be continuous process
[H, K] Control valve: Maintain with setting pressure
[I] Seperator: separation of decompressed carbon dioxide and extract
[L] Chiller: liquefied through cooling of carbon dioxide

Claims (2)

A method of separating oil and carbon dioxide by decompressing supercritical carbon dioxide dissolved in oil using supercritical carbon dioxide in the method of separating oil and polymer resin from pneumatic depressions of polymer resin and oil.
Extraction method using supercritical carbon dioxide for oil extraction method in the process of manufacturing wet separation membrane for lithium ion secondary battery.

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