Clean extraction method of gutta-percha separated out by freezing in cold region

Abstract

The invention provides an extraction method of gutta-percha separated out by freezing in a cold region. The extraction method comprises the following steps: screening, kneading, cleaning and drying eucommia seed shells to obtain a crude rubber raw material; mixing the crude rubber raw material with an n-hexane solvent, and extracting a rubber solution in countercurrent extraction equipment; layering, freezing and separating out the solvent and the gutta-percha of the gutta-percha liquid in a chromatography tank; and carrying out solid-liquid desolventizing on the separated rubber solution through a centrifugal machine to obtain a gutta-percha solution, and carrying out secondary desolventizing through a drying machine to obtain refined gutta-percha. According to the method, the large temperature difference of a cold region is utilized for batch production of the bio-based rubber, a green freezing precipitation technology is adopted, natural low temperature is fully utilized, and the characteristics of environmental protection, energy conservation, high efficiency and cleanness are embodied. The technology not only meets the increasing demand of the market on the high-performance gutta-percha material, but also promotes the sustainable development of related industries.

Description

Technical Field

[0001] The invention belongs to the technical field of eucommia gum preparation, and particularly relates to a clean extraction method of eucommia gum. Background Art

[0002] With the advancement and development of technology, the development of bio-based polymers is of great significance. Eucommia ulmoides is a precious economic plant unique to China and a deciduous tree belonging to the genus Eucommia of the Eucommia family. Eucommia gum is contained in the roots, stems, leaves, flowers and fruits of Eucommia ulmoides. In Eucommia ulmoides plants, the gum content of dry bark is 11% to 16%, the gum content of dry fruit is 12%, the gum content of dry leaves is 2% to 5%, and the gum content of old twigs and bark is 10%. As a kind of bio-based polymer material, Eucommia gum is an isomer of natural rubber and has the characteristics of rubber and plastic duality. Among them, Eucommia gum has the advantages of excellent insulation, water resistance, acid and alkali corrosion resistance, shock resistance and tear resistance, and its demand in tires and rubber products is increasing. According to the current market research, in professional fields such as biomedicine, green energy, aerospace, transportation, and medical devices, the performance and sustainability requirements of Eucommia gum materials are becoming increasingly stringent. The demand for such a material with fatigue resistance, water resistance and excellent mechanical properties is growing in the application market, so it is particularly important to accelerate its large-scale production and application.

[0003] Eucommia gum is extracted from Eucommia ulmoides plants. Eucommia gum exists in cells with low gum content and high viscosity, and the cell wall contains natural organic polymers such as cellulose and lignin. Therefore, the process of extracting Eucommia gum from Eucommia ulmoides plants is complicated. For Eucommia gum materials, extracting and purifying Eucommia gum is an important link to achieve its excellent performance and wide application. At present, there are some Eucommia gum extraction processes, such as mechanical extraction, alkali solution immersion extraction and other methods, but these methods still have problems such as high cost, low extraction rate, and environmental pollution. Summary of the invention

[0004] The purpose of the present invention is to overcome the above disadvantages and propose a new eucommia gum extraction technology, the purpose is to use the cold region freezing precipitation process to achieve the clean extraction of eucommia gum, while achieving large-scale industrial production of eucommia gum.

[0005] The present invention uses eucommia seed shell as the raw material of eucommia gum to extract high-content eucommia gum. The purpose of the present invention is to provide a green freezing precipitation extraction method for eucommia gum, which utilizes the low natural climate in northern winter to achieve freezing precipitation of eucommia gum under natural conditions, reduce energy consumption, and achieve green and clean extraction. Eucommia gum is precipitated by making full use of the natural low temperature in cold areas, and after freezing treatment, the molecular weight distribution becomes narrower, thereby improving the consistency and stability of the material. This method not only improves the extraction efficiency, but also retains the natural structure of eucommia gum.

[0006] In order to achieve the purpose of high purification efficiency, low cost and green environmental protection, the present invention provides the following technical solution: a clean extraction method for freezing and precipitating eucommia gum in cold regions, characterized in that it comprises the following steps:

[0007] (1) Raw material pretreatment:

[0008] The eucommia seed shells are put into a feeder, and the seed shells in the feeder are transported to an oscillator through a first conveyor for oscillation screening, and then the screened eucommia seed shells are transported to a kneading machine through a second conveyor for repeated kneading. The kneaded eucommia seed shells are then rinsed with clean water to remove residual impurities such as eucommia seed residues and eucommia shell debris. The rinsed eucommia seed shells are placed in a second dryer for drying to obtain eucommia seed shell rubber silk balls.

[0009] (2) Countercurrent extraction

[0010] The eucommia seed shell rubber ball obtained by (1) is conveyed to the container tank of the countercurrent extractor via a feed conveyor for 80 minutes of countercurrent extraction. During the extraction process, the temperature of the equipment is controlled at about 50°C. Finally, a crude rubber solution with a concentration of about 3% is obtained. After the extraction is completed, the obtained crude rubber solution is filtered through a filter to remove impurities and particulate matter. The filtered rubber solution is left to stand for 30 minutes. This step helps to further precipitate and separate tiny suspended matter to obtain a rubber solution without suspended matter.

[0011] (3) Freezing precipitation

[0012] The glue solution without suspended matter obtained in (2) is slowly injected into the chromatography tank, and the temperature in the chromatography tank is controlled at about -12°C. At this temperature, the glue solution and the n-hexane solvent are cooled for nearly 30 minutes, and significant stratification occurs. The upper n-hexane solvent flows back to the solvent tank for subsequent recycling. The eucommia gum glue solution after stratification will be subjected to the next step of continuous desolventization treatment.

[0013] (4) Continuous desolventization

[0014] The eucommia gum liquid obtained by (3) is subjected to solid-liquid separation and desolventizing treatment by a centrifuge. The centrifuge can ensure that the liquid is evenly stressed during the centrifugation process, thereby effectively separating the eucommia gum and the residual n-hexane solvent, and obtaining a preliminary concentrated eucommia gum liquid with a concentration of up to about 70%. In order to further improve the purity of eucommia gum, the eucommia gum that has undergone the initial desolventizing treatment is sent to the third dryer to achieve secondary desolventizing, and the concentration of eucommia refined gum can reach about 97%, providing high-quality raw materials for subsequent deep processing and application.

[0015] Compared with the prior art, the present invention has obvious beneficial effects. It can be seen from the above technical scheme that:

[0016] 1. The present invention adopts freezing treatment technology, utilizes the cold climate of northern winter, and freezes and precipitates the mixed solvent containing eucommia gum and normal hexane. Eucommia gum and normal hexane solvent are layered by natural cooling conditions, which reduces the use of energy and saves costs. After freezing treatment, the molecular weight distribution narrows, which helps to improve the consistency and stability of eucommia gum molecules.

[0017] 2. In the present invention, the recycling of solvents is combined with the continuity and automation of process steps, which further improves production efficiency, reduces production costs, and reduces environmental pollution. It conforms to the concept of green chemistry and sustainable development, and reflects the environmental protection of the present invention.

[0018] 3. The present invention adopts secondary desolventizing treatment to improve the quality of Eucommia gum. Through secondary desolventizing, the n-hexane solvent is more effectively separated, and the obtained Eucommia gum product has higher purity and more stable quality.

[0019] 4. The present invention uses existing equipment to achieve industrial-scale production of extracting eucommia gum, which can improve production efficiency and reduce costs, and can also promote technological innovation and enhance market competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a flow chart of a clean extraction method of Eucommia gum precipitated by freezing in cold regions.

[0021] Figure 2 It is a process flow chart of the present invention.

[0022] Figure 3 The eucommia seed shell rubber silk ball is obtained after kneading and drying in step 1 of the present invention.

[0023] Figure 4 The eucommia gum is obtained after secondary desolventization in step 4 of the present invention.

[0024] Figure 5 This is a universal chromatogram of a broadly distributed unknown sample of the frozen precipitation sample according to embodiment 1 of the present invention.

[0025] Figure 6 This is a graph showing the gel chromatography detection results of embodiment 1 of the present invention.

[0026] In the figure, 1, the first dryer; 2, the feeder; 3, the first conveyor; 4, the vibrator; 5, the second conveyor; 6, the kneading machine; 7, the cleaning machine; 8, the second dryer; 9, the feed conveyor; 10, the container tank; 11, the first glue pump; 12, the filter; 13, the chromatography tank; 14, the second glue pump; 15, the centrifuge; 16, the first condenser; 17, the third dryer; 18, the solvent tank; 19, the third glue pump; 20, the spray pump; 21, the countercurrent extractor; 22, the discharge conveyor; 23, the second condenser. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in conjunction with the accompanying drawings and specific embodiments. It should be understood that the embodiments are only used to further illustrate and explain this patent, and are not used to limit this patent application. The process structure and extraction method of the present invention are further described in conjunction with the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Specific implementation 1:

[0029] A clean extraction method for freezing and precipitating eucommia gum in cold regions comprises the following steps: placing eucommia seed shells into a feeder 2, the eucommia seed shells pass through the feeder to a first conveyor 3, and are sent from the first conveyor 3 to an oscillator 4 for oscillation screening to obtain clean eucommia seed shells, and are sent to a kneading machine 6 through a second conveyor 5 for cleaning, and then sent to a cleaning machine 7 to clean residual impurities, and the cleaned eucommia seed shells are sent to a second dryer 8 for drying to obtain eucommia seed shell gum balls. The eucommia seed shell gum balls are sent to a countercurrent extractor 21 through a feed conveyor 9, and the countercurrent extractor 21 includes a container tank 10. The solvent tank 18 is used to store the n-hexane solvent. The n-hexane solvent enters the countercurrent extractor 21 from the solvent tank 18 through the third glue pump 19. The n-hexane solvent can be fully mixed with the crude glue raw material in the countercurrent extractor 21 through the spray pump 20. The countercurrent extraction is carried out for 80 minutes in the countercurrent extractor 21. The temperature is controlled at 50°C, and a glue solution with a concentration of about 3% can be obtained. The waste material is sent to the first dryer 1 for treatment through the discharge conveyor 22. The obtained n-hexane solvent vapor is sent to the solvent tank 18 after being cooled by the second condenser 23. The glue solution is sent to the filter 12 for treatment through the first glue pump 11. The filtered glue solution is left to stand for 30 minutes. Then the glue solution is sent to the chromatography tank 13, and the temperature in the chromatography tank 13 is controlled at -12°C. After 30 minutes of cooling, the purpose is to wait for the Eucommia gum and the n-hexane solvent to be separated. The upper layer is the n-hexane solvent, and the lower layer is the Eucommia gum solution. The n-hexane solvent finally flows back to the solvent tank 18. The eucommia gum liquid is sent to the centrifuge 15 through the second glue liquid pump 14 to separate the eucommia gum and the residual solvent to obtain the eucommia gum liquid concentrated to about 70%, and the n-hexane solvent finally flows back to the solvent tank 18. The glue liquid is further sent to the third dryer 17 for secondary desolventizing treatment to remove the remaining trace n-hexane solvent, and the n-hexane solvent vapor is cooled by the first condenser 16 and sent to the solvent tank 18, and finally the eucommia gum with a concentration of 97.81% is obtained. Specific implementation 2:

[0031] A clean extraction method for freezing and precipitating eucommia gum in cold regions, comprising the following steps: placing eucommia seed shells into a feeder 2, the eucommia seed shells pass through the feeder 2 to a first conveyor 3, and are sent from the first conveyor 3 to an oscillator 4 for oscillation screening to obtain clean eucommia seed shells, and are sent to a kneading machine 6 through a second conveyor 5 for cleaning, and then sent to a cleaning machine 7 to clean residual impurities, and the cleaned eucommia seed shells are sent to a second dryer 8 for drying to obtain eucommia seed shell gum balls. The eucommia seed shell gum balls are sent to a countercurrent extractor 21 through a feed conveyor 9, and the countercurrent extractor 21 includes a mixing container tank 10. In the mixing container tank 10, the crude rubber raw material and the n-hexane solvent are mixed at a solid-liquid ratio of 1:13, wherein the solvent tank 18 is used to store the n-hexane solvent, and the n-hexane solvent enters the countercurrent extractor 21 from the solvent tank 18 through the third glue pump 19, and the n-hexane solvent can be fully mixed with the crude rubber raw material in the countercurrent extractor 21 through the spray pump 20, and the countercurrent extraction is carried out in the countercurrent extractor 21 for 90 minutes, and the temperature is controlled at 55°C, and a glue solution with a concentration of about 5% can be obtained. The waste is sent to the first dryer 1 through the discharge conveyor 22 for treatment, and the obtained n-hexane solvent vapor is sent to the solvent tank 18 after being cooled by the second condenser 23. The glue solution is sent to the filter 12 for treatment through the first glue pump 11, and the filtered glue solution is left to stand for 40 minutes. Then the glue solution is sent to the chromatography tank 13, and the temperature in the chromatography tank 13 is controlled at -20°C. After cooling for 30 minutes, the purpose is to wait for the Eucommia gum and the n-hexane solvent to be separated into layers, the upper layer is the n-hexane solvent, the lower layer is the Eucommia gum solution, and the n-hexane solvent finally flows back to the solvent tank 18. The Eucommia gum solution is sent to the centrifuge 15 through the second glue pump 14 to separate the Eucommia gum and the residual n-hexane solvent to obtain the Eucommia gum glue solution concentrated to about 70%, and the n-hexane solvent finally flows back to the solvent tank 18. The glue solution is further sent to the third dryer 17 for secondary desolventizing treatment to remove the remaining trace n-hexane solvent, and the n-hexane solvent vapor is sent to the solvent tank 18 after being cooled by the first condenser 16, and finally Eucommia gum with a concentration of more than 97% is obtained. Specific implementation 3:

[0033] A clean extraction method for freezing and precipitating eucommia gum in cold regions, comprising the following steps: placing eucommia seed shells into a feeder 2, the eucommia seed shells pass through the feeder 2 to a first conveyor 3, and are sent from the first conveyor 3 to an oscillator 4 for oscillation screening to obtain clean eucommia seed shells, and are sent to a kneading machine 6 through a second conveyor 5 for cleaning, and then sent to a cleaning machine 7 to clean residual impurities, and the cleaned eucommia seed shells are sent to a second dryer 8 for drying to obtain eucommia seed shell gum balls. The eucommia seed shell gum balls are sent to a countercurrent extractor 21 through a feed conveyor 9, and the countercurrent extractor 21 includes a mixing container tank 10. In the mixing container tank 10, the crude rubber raw material and the n-hexane solvent are mixed at a solid-liquid ratio of 1:15, wherein the solvent tank 18 is used to store the n-hexane solvent, and the n-hexane solvent enters the countercurrent extractor 21 from the solvent tank 18 through the third glue pump 19, and the n-hexane solvent can be fully mixed with the crude rubber raw material in the countercurrent extractor 21 through the spray pump 20, and the countercurrent extraction is carried out in the countercurrent extractor 21 for 100 minutes, and the temperature is controlled at 60°C, and a glue solution with a concentration of about 7% can be obtained. The waste is sent to the first dryer 1 through the discharge conveyor 22 for treatment, and the obtained n-hexane solvent vapor is sent to the solvent tank 18 after being cooled by the second condenser 23. The glue solution is sent to the filter 12 for treatment through the first glue pump 11, and the filtered glue solution is left to stand for 50 minutes. Then the glue liquid is sent to the chromatography tank 13, and the temperature in the chromatography tank 13 is controlled at -20 ° C. After 40 minutes of cooling, the purpose is to wait for the Eucommia gum and the n-hexane solvent to be separated, the upper layer is the n-hexane solvent, the lower layer is the Eucommia gum liquid, and the n-hexane solvent finally flows back to the solvent tank 18. The Eucommia gum liquid is sent to the centrifuge 15 through the second glue liquid pump 14 to separate the Eucommia gum and the residual n-hexane solvent to obtain the Eucommia gum glue liquid concentrated to about 75%, and the n-hexane solvent finally flows back to the solvent tank 18. The glue liquid is further sent to the third dryer 17 for secondary desolventizing treatment to remove the remaining trace n-hexane solvent, and the n-hexane solvent vapor is sent to the solvent tank 18 after being cooled by the first condenser 16, and finally Eucommia gum with a concentration of more than 97% is obtained. Specific implementation 4:

[0035] A clean extraction method for freezing and precipitating eucommia gum in cold regions, comprising the following steps: placing eucommia seed shells into a feeder 2, the eucommia seed shells pass through the feeder 2 to a first conveyor 3, and are sent from the first conveyor 3 to an oscillator 4 for oscillation screening to obtain clean eucommia seed shells, and are sent to a kneading machine 6 through a second conveyor 5 for cleaning, and then sent to a cleaning machine 7 to clean residual impurities, and the cleaned eucommia seed shells are sent to a second dryer 8 for drying to obtain eucommia seed shell gum balls. The eucommia seed shell gum balls are sent to a countercurrent extractor 21 through a feed conveyor 9, and the countercurrent extractor 21 includes a mixing container tank 10. In the mixing container tank 10, the crude rubber raw material and the n-hexane solvent are mixed at a solid-liquid ratio of 1:10, wherein the solvent tank 18 is used to store the n-hexane solvent, and the n-hexane solvent enters the countercurrent extractor 21 from the solvent tank 18 through the third glue pump 19, and the n-hexane solvent can be fully mixed with the crude rubber raw material in the countercurrent extractor 21 through the spray pump 20, and the countercurrent extraction is carried out in the countercurrent extractor 21 for 100 minutes, and the temperature is controlled at 50°C, and a glue solution with a concentration of about 5% can be obtained. The waste is sent to the first dryer 1 through the discharge conveyor 22 for treatment, and the obtained n-hexane solvent vapor is sent to the solvent tank 18 after being cooled by the second condenser 23. The glue solution is sent to the filter 12 for treatment through the first glue pump 11, and the filtered glue solution is left to stand for 30 minutes. Then the glue liquid is sent to the chromatography tank 13, and the temperature in the chromatography tank 13 is controlled at -15 ° C. After cooling for 30 minutes, the purpose is to wait for the Eucommia gum and the n-hexane solvent to be separated, the upper layer is the n-hexane solvent, the lower layer is the Eucommia gum liquid, and the n-hexane solvent finally flows back to the solvent tank 18. The Eucommia gum liquid is sent to the centrifuge 15 through the second glue liquid pump 14 to separate the Eucommia gum and the residual n-hexane solvent to obtain the Eucommia gum glue liquid concentrated to about 75%, and the n-hexane solvent finally flows back to the solvent tank 18. The glue liquid is further sent to the third dryer 17 for secondary desolventizing treatment to remove the remaining trace n-hexane solvent, and the n-hexane solvent vapor is sent to the solvent tank 18 after being cooled by the first condenser 16, and finally Eucommia gum with a concentration of more than 97% is obtained.

[0036] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A clean extraction method for freezing and precipitating eucommia gum in cold regions, characterized in that: The following steps are involved: Step 1: Raw material pretreatment The eucommia seed shells are placed in a feeder (2), and transported to an oscillator (4) through a first conveyor (3) for oscillation and screening. The screened eucommia seed shells are transported to a kneading machine (6) through a second conveyor (5) for kneading, and then transported to a cleaning machine (7) for cleaning and removal of impurities. Finally, the eucommia seed shells from which impurities have been removed are transported to a second dryer (8) for drying to obtain eucommia seed shell rubber silk balls; Step 2: Countercurrent extraction The eucommia seed shell rubber silk ball obtained in step 1 is conveyed to the container tank (10) of the countercurrent extractor (21) via a feed conveyor (9), and countercurrent extraction is performed for 80 minutes to obtain a 3% concentration of rubber solution, and then the rubber solution is conveyed to the filter (12) through a first rubber solution pump (11) and filtered and allowed to stand for 30 minutes to remove impurities, thereby obtaining a rubber solution without suspended matter; Step 3: Freeze-out The glue solution without suspended matter obtained in step 2 is injected into a chromatography tank (13), the temperature in the chromatography tank (13) is controlled at about -12°C, the glue solution without suspended matter and the n-hexane solvent are cooled for nearly 30 minutes to obtain a layered solution of the n-hexane solvent and eucommia gum, and the n-hexane solvent after layering is returned to the solvent tank (18) for recycling; Step 4: Continuous desolventization The eucommia gum liquid after stratification is transported to a centrifuge (15) through a second liquid pump (14) for solid-liquid separation and desolventization to obtain the eucommia gum liquid with a concentration of 70%. The solvent after separation and desolventization flows into a solvent tank (18). The eucommia gum subjected to the primary desolventization is passed through a third dryer (17) for secondary desolventization to remove the remaining n-hexane solvent and obtain eucommia refined gum. The solvent vapor evaporated during the drying process is transported back to the solvent tank (18) through a first condenser (16).

2. A clean extraction method for freezing and precipitating eucommia gum in cold regions as claimed in claim 1, characterized in that: The drying standard of the drying equipment in step 1 is to dry the rubber content of the eucommia seed shell rubber thread to 25% or more.

3. A clean extraction method for freezing and precipitating eucommia gum in cold regions as claimed in claim 1, characterized in that: In the step 2, the equipment temperature in the countercurrent extractor is controlled at above 50° C. to ensure that the eucommia seed shells and the n-hexane solvent are fully mixed.

4. A clean extraction method for freezing and precipitating eucommia gum in cold regions as claimed in claim 1, characterized in that: In step 3, the temperature of the chromatography tank is controlled at -12°C or below, and the cooling and precipitation is carried out for more than 30 minutes to achieve effective separation of the n-hexane solvent and eucommia gum.

5. The clean extraction method of Eucommia gum precipitated by freezing in cold regions as claimed in claim 1, characterized in that: The solid-liquid separation and desolventizing process of the centrifuge can obtain eucommia gum liquid with a concentration of more than 70%, and secondary desolventizing is performed by a dryer to obtain eucommia refined gum with a concentration of 97%-97.81%.

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