WO2022105916A1 - Use of neem bark pigment in preparation for multifunctional wool fabric - Google Patents

Abstract

Use of neem bark pigment in preparation for multifunctional wool fabric, relating to the technical field of natural waste utilization and textile dyeing and finishing. The method for extracting neem bark pigment comprises the following steps: adding neem bark powder into a mixed solvent of water and ethanol and mixing uniformly using a high-speed wall-breaking machine, and extracting at a blade rotation speed of 20000-42000 r/min; the extraction pH being 9-11; the extraction temperature being 45-75°C, and the extraction time being 10-60 min; and after the extraction, performing centrifugation, suction filtering, concentration and drying to obtain neem bark pigment. Using a high-speed wall-breaking method can increase the yield of crude neem bark pigment to 18.77%; the wool fabric which is dyed with neem bark pigment prepared using the described method has a dark colour; the anti-moth effect is improved compared with that of an undyed fabric, and the weight loss is reduced by 61.5%; and the anti-ultraviolet performance is good, the UPF value is increased by 24 times compared with that of the undyed wool fabric, and fluorescent light of different colours can be exhibited under excitation light of different wavelengths.

Description

Application of Neem Bark Pigment in Preparation of Multifunctional Plush Fabric technical field

The invention relates to the application of neem bark pigment in preparing multifunctional plush fabric, and belongs to the technical field of natural waste utilization and textile dyeing and finishing.

Background technique

With the development of society and economy, more and more attention has been paid to the protection of the ecological environment. As a common textile in daily life, wool fabrics need to develop more environmentally friendly and ecologically friendly processing techniques. However, at present, the dyeing, moth-proof and UV-resistant functional finishing of wool fabrics are still dominated by chemical synthetic products. The harmful substances produced in the process of dye synthesis and the waste water after printing and dyeing will damage the ecological environment, and the synthetic dyes are not easy to degrade and are carcinogenic. At present, synthetic pyrethrins, naphthalene, p-chlorodiphenyl, etc. are mostly used in moth-proof finishing of wool fabrics. Although these moth-proofing agents have significant anti-moth effect, they are harmful to human body, and will enter the water cycle with the washing of textiles and pollute the ecology. surroundings. Anti-ultraviolet finishing of fabrics is mainly to attach TiO ₂ , ZnO and other nanoparticles to the surface of fabrics to prepare anti-ultraviolet fabrics. This method has a simple process, but the cost is high and the prepared anti-ultraviolet fabrics are not washable. The natural plant extract has good compatibility with the environment, is degradable, harmless to the human body, the raw materials are readily available, and the cost is low. It can also be used as a dyeing and finishing preparation to finish wool fabrics, which can meet the dyeing needs of textiles and endow wool fabrics with various functions. sex.

Neem is a deciduous tree plant of the Neem family, distributed in many regions of my country. The neem tree is often used for furniture because of its rapid growth and strong wood, so the neem bark is often discarded as a natural waste. The root bark of Neem can be used as medicine for deworming and treatment of skin moss. Neem bark contains a lot of flavonoids and terpenoids, terpenoids have strong insecticidal, antibacterial and antioxidant activities. Among them, the main active ingredient of flavonoids is rutin, and the main active ingredient of terpenoids is neem.

At present, the research on the utilization of waste resources of neem bark mainly includes medicinal use, extraction of neem to make pure plant-derived insecticides, and use as fertilizers. For example, Zhang Chunsong invented a method for preparing a whitening and spot-reducing emulsion containing neem leaf extract (Patent Application Publication No. CN 108685795A), a whitening spot-reducing emulsion made of neem leaf, licorice root, maca extract and buckwheat starch; Xie Siji invented a preparation and application method of an organic insecticide Neem stock solution (Patent Application Publication No. CN108208031A). Insecticide on vegetables, the effect is obvious. The insecticidal effect of adding abamectin is doubled; Yu Yingheng invented a kind of neem organic biological fertilizer (patent application publication number CN107141111A), which adopts the mixture of neem root powder and pig manure, combined with charcoal soil, vermiculite, bran , Organic material decomposing agent, composted to become neem bio-organic fertilizer, can shorten the neem transplant slow seedling period, improve the survival rate, improve fertilizer efficiency, relieve root poison damage, and promote root development.

Neem bark extraction methods mainly include solvothermal extraction, Soxhlet extraction, ultrasonic-microwave extraction. For example, Qi Yunji invented a method for preparing the neem bark extract (patent publication number CN110623886A), placing a Soxhlet extractor in a microwave reactor to extract neem, filtering, decolorizing, and concentrating under reduced pressure to obtain the neem bark extract , the content of azadirachtin in the obtained extract is higher, up to 1.8%, and the impurities are less, and its anti-inflammatory and acaricidal functions can be used to make cosmetics. However, solvothermal extraction and Soxhlet extraction are difficult to improve the yield; while ultrasonic-microwave extraction equipment is expensive and the temperature is difficult to accurately control.

SUMMARY OF THE INVENTION

In order to solve at least one of the above problems and enrich the types of natural functional dyes, the present invention provides a simple and low-cost method for high-speed wall-breaking extraction of neem bark pigment, and the method of the present invention can improve the yield of neem bark crude product; and The wool fabric dyed with Neem bark pigment has deep color and good color fastness, and also has the functions of anti-moth, anti-ultraviolet, fluorescence and so on.

The first object of the present invention is to provide a kind of method of extracting neem bark pigment, comprising the following steps:

The neem bark powder is added to the mixed solvent of water and ethanol, and the high-speed wall breaker is used to mix evenly, and the extraction is carried out at a blade speed of 20,000 to 42,000 r/min; the extraction pH is 9 to 11; the extraction temperature is 45 to 75 ° C. The time is 10-60 min; after extraction, centrifugation, suction filtration, concentration and drying are performed to obtain the neem bark pigment.

In an embodiment of the present invention, the extraction temperature is 65°C.

In an embodiment of the present invention, the particle size of the Neem bark powder is 10-20 meshes.

In an embodiment of the present invention, the mass percentage content of ethanol in the mixed solvent is 20-60%.

In an embodiment of the present invention, the mass ratio of the mixed solvent to the neem bark powder is 30-50:1, more preferably 40:1.

In one embodiment of the present invention, the pH of the extraction is adjusted by adding sodium hydroxide solution, and the concentration of the sodium hydroxide solution is 0.95 g/L.

In an embodiment of the present invention, the extraction is to reduce the rotation speed of the blade to 20500 r/min and extract for 50 minutes after the rotation of the blade is 42,000 r/min for 10 minutes.

In an embodiment of the present invention, the centrifugation is performed by using a high-speed centrifuge with a rotational speed of 10,000 r/min and centrifugation for 10 minutes.

In an embodiment of the present invention, the suction filtration is performed by using a 100 nm pore size Buchner funnel and quantitative filter paper for suction filtration.

In an embodiment of the present invention, the concentration is to use rotary evaporation to recover ethanol and concentrate the feed liquid, and the solid content of the concentrate is 4.80%.

In an embodiment of the present invention, the drying is freeze-drying, the temperature of freeze-drying is -40°C, and the time is 36h.

The second object of the present invention is the neem bark pigment extracted by the method of the present invention.

The third object of the present invention is the application of the neem bark pigment of the present invention in the preparation of multifunctional plush fabrics.

In an embodiment of the present invention, the plush fabric includes various plush textiles made from wool and cashmere, rabbit hair and other animal hairs through modern textile technology.

In one embodiment of the present invention, the application is to dye plush fabrics with Neem bark pigment as a dye.

In one embodiment of the present invention, the described dyeing is specifically:

The method of direct dyeing is adopted, the amount of Neem bark pigment is 18% o.w.f, the liquor ratio is 1:25, the pH of the dyeing bath is 3-5, the dyeing is at room temperature, the heating rate is 2 °C/min, the temperature is raised to the dyeing temperature of 95 °C, and the dyeing is carried out by heat preservation. 90min; then washed with water to remove floating color to obtain multifunctional plush fabric.

Beneficial effects of the present invention:

(1) The present invention adopts the high-speed wall-breaking method to extract the crude product of Neem bark extract, and the yield is 18.77%, while the yield of solvothermal extraction is 13.31%.

(2) The dyed wool fabric of the present invention has strong anti-ultraviolet performance, the UPF value is 24 times higher than that of the undyed fabric, and also has functions such as strong fluorescence and certain moth-proof properties, and the dyed fabric The weight loss caused by moth-eaten is 61.5% less than that of undyed fabrics.

Description of drawings

Figure 1 is the molecular structure formula of the main active substances in Neem bark; wherein (a) rutin; (b) neem.

Fig. 2 is the crude product yield of neem bark pigment obtained at different extraction temperatures.

Fig. 3 is the crude product yield of the neem bark pigment obtained with different solid-liquid ratios.

Fig. 4 is the crude product yield of Neem bark pigment obtained in Example 1, Comparative Example 1, and Comparative Example 2.

Fig. 5 is the Fourier transform infrared (FT-IR) spectrum of the neem bark pigment obtained in Example 1, Comparative Example 1 and Comparative Example 2; wherein (a) Comparative Example 1; (b) Comparative Example 2; (c) ) Example 1.

FIG. 6 shows the colors of wool fabrics directly dyed with different dyebath pH values in Example 5. FIG.

Figure 7 shows the fluorescence effect of wool fabrics before and after dyeing; (a) green fluorescence; (b) red fluorescence; (c) blue fluorescence.

8 is a histogram of fluorescence intensity of different colors of wool fabrics before and after dyeing; wherein (a) Comparative Example 5; (b) Example 4; (c) Comparative Example 4.

Detailed ways

The preferred embodiments of the present invention will be described below, and it should be understood that the embodiments are used to better explain the present invention and are not intended to limit the present invention.

testing method:

1. Crude product yield: after extraction and suction filtration of Neem bark powder, take the supernatant liquid by rotary evaporation and dry to obtain solid powder, and weigh the powder mass m ₁ ; the extraction residue is washed with 500 mL of distilled water, and the washed liquid is dried to obtain For the solid powder, weigh the powder mass m ₂ ; crude product yield=((m ₁ +m ₂ )-mass of sodium hydroxide added)/mass of neem bark raw material added.

2. Fourier transform infrared (FT-IR) analysis: After grinding the neem bark pigment to about 20 mesh, use Fourier transform infrared spectrometer (FT-IR) to conduct infrared test in the range of wave number 500-4000cm ^-1 .

3. Determination of total flavonoids content: first dilute the original solution by 10 times (water and mixed solvent extracts are adjusted to pH=7 and then dilute), draw 1 mL of the 10-fold diluted sample into a 10 mL volumetric flask, the determination method is: NaNO ₂ -Al(NO ₃ ) ₃ -NaOH color development method; the specific total flavonoid yield is calculated as: total flavonoid yield (%)=crude extract yield (%)×total flavonoid content (mg/g).

4. Determination of total polyphenol content: draw 1 mL of the sample diluted 10 times into a 10 mL volumetric flask, the determination method is: Folin phenol colorimetric method. Calculation method of total polyphenol yield: total polyphenol yield (%) = extract crude product yield (%) × total polyphenol content (mg/g).

5. Color measurement of dyed wool fabrics: measure the L*, a*, b*, h°, c*, K/S values of the dyed fabrics, and each sample is measured in parallel for 4 times and the average value is obtained.

6. Anti-moth performance:

According to the national standard FZT 20004-2009, the moth-proof performance of wool fabrics after direct dyeing was tested by the method of biological analysis of moth-proof performance, and the moth-proof detection experiment was carried out by black beetle. According to Table 1 and Table 2, the anti-moth effect was evaluated visually.

Table 1 Assessment of visible surface damage to fabrics

Numbering	visible surface damage
1	No damage seen
2	very rare damage
3	moderate damage
4	serious damage

Table 2 evaluates the fabric with visible decay and holes

Numbering	cavities
A	No damage seen
B	Part of the yarn or fiber is broken
C	Parts of the yarn or fibers are broken and some small holes
D	The whole wormhole

Calculate the weight loss △m of the sample and the control sample due to moth, see the following formula:

In the formula: m ₀ - the weight of the sample before adding larvae or the sample for controlling the decay, mg; m ₁ - the weight of the sample after removing the larvae or the sample for controlling the decay, mg; m ₂ - the moisture regain control The average weight of the original weight of the sample, mg; m ₃ —— the average weight of the final weight of the controlled moisture regain sample, mg.

7. Evaluation of anti-ultraviolet performance: According to the national standard GB/T 18830-2009, the ultraviolet protection performance of neem bark dyed wool fabrics before and after dyeing was determined.

8. Fluorescence performance evaluation: Using a Nikon Ti-s inverted fluorescence microscope, the wool yarn before and after dyeing (the wool yarn used in the test was taken from the dyed wool fabric) was used to observe the fluorescence phenomenon and detect the fluorescence intensity (excitation filter 465- 495nm; absorption filter 515-555nm), all tests were carried out at room temperature.

Example 1

A method for extracting neem bark pigment, comprising the following steps:

10g 20 purpose Neem bark powder was added to the mixed solvent of 400g water and ethanol (the concentration of ethanol was 40%), and a high-speed wall breaker was used to mix uniformly to extract; the extraction pH (adding sodium hydroxide solution to adjust) was 11, The extraction temperature was 65 °C, and the extraction time was 60 min (the blade speed was 42,000 r/min for 10 min, and the blade speed was reduced to 20,500 r/min for 50 min); Solid-liquid separation; then use rotary evaporation to recover ethanol and concentrate the feed liquid (solid content is 4.80%), freeze-dry after concentration (temperature is -40°C, time is 36h) to obtain brown powder, namely Neem bark pigment.

The optimization of embodiment 2 extraction temperature

The extraction temperature in Example 1 was adjusted to be 25, 35, 45, 55, and 75° C., and the others were the same as those in Example 1 to obtain Neem bark pigment.

The obtained Neem bark pigment is tested for performance, and the test results are shown in Figure 2. It can be seen from Figure 2 that: with the increase of temperature, the crude product yield of Neem bark pigment gradually increases, and the crude product yield is the lowest at 25 ° C. , was 15.11%, and the crude product yield was the highest at 65°C (Example 1), which was 18.77%. But the crude yield of Neem bark pigment decreased slightly at 75℃.

The optimization of embodiment 3 solid-liquid ratio

Adjust the material-to-liquid ratio (mass ratio of Neem bark powder and mixed solvent) in Example 1 to 1:10, 1:20, 1:30, 1:50, 1:60, and the others are consistent with Example 1, Get the neem bark pigment.

The obtained Neem bark pigment is tested for performance, and the test results are shown in Figure 3. It can be seen from Figure 3 that: when the solid-liquid ratio is 1:10, the crude product yield is the lowest, which is 15.51%, and when the solid-liquid ratio is 1:40 (Example 1), the crude product yield was the highest at 18.77%, and when the solid-liquid ratio was greater than 1:40, the crude product yield difference was small, indicating that the crude product yield became stable from the solid-liquid ratio from 1:40. , Neem bark pigment has been basically dissolved. Comprehensive consideration, the material-liquid ratio should be selected as 1:40.

Comparative Example 1

The step of adjusting pH in Example 1 was omitted, and the others were the same as those in Example 1 to obtain Neem bark pigment.

Comparative Example 2

The mixed solvent in Example 1 was adjusted to be water, and the others were the same as those in Example 1 to obtain Neem bark pigment.

The Neem bark pigment obtained by Example 1, Comparative Example 1, Comparative Example 2 is carried out performance test, and the test result is shown in Figure 4, Figure 5, as can be seen from Figure 4: the crude product of the Neem bark pigment extracted in Example 1 is obtained. The highest rate is 18.77%.

As can be seen from Figure 5: the Neem bark pigments obtained in Example 1, Comparative Example 2, and Comparative Example 1 have absorption peaks with wide peak shapes in the vicinity of ^3234-1 , ^3264-1 , and 3256 cm- ¹ , respectively, indicating that Neem There are a large number of phenolic hydroxyl groups or hydroxyl groups on sugar substances in the skin pigment, and the three kinds of Neem bark pigments have absorption peaks at 1603-1, ^1552-1 , 1579cm ^{-1 respectively} , indicating the existence of benzene rings; ^1036-1 , The absorption peaks at 1057 ^-1 and 1043 cm ^-1 correspond to sugar (glycosides) components, and the peaks in Comparative Example 1 and Example 1 are more obvious than those in Comparative Example 2, indicating the neem bark of Example 1 and Comparative Example 1. The content of sugars (glycosides) in the pigment was higher than that of the control example 2.

Table 3 is the test result of total flavonoids and total phenolic content in the Neem bark pigment obtained by Example 1, Comparative Example 1, Comparative Example 2, as can be seen from Table 3: total flavonoids in the Neem bark pigment obtained in Example 1 The highest content is 742.91mg/g; the total phenol content is higher, reaching 241.69mg/g;

The yield of total flavonoids in the neem bark pigment obtained in Table 3 Example 1 and Comparative Examples 1 and 2

Comparative Example 3

The high-speed wall breaker in Example 1 was omitted, and the thermal extraction was carried out directly.

The obtained Neem bark pigment was tested for performance, and the test result was: the crude product yield was 13.3%.

Example 4: Dyeing wool fabric with Neem bark pigment

The neem pigment obtained in Example 1 adopts the direct dyeing method, the dye (neem bark pigment) consumption is 18% o.w.f, the bath ratio is 1:25, the pH of the dyeing bath is 4, the dyeing at room temperature, the heating rate 2 ℃/min, the temperature rises To the dyeing temperature of 95 ℃, heat preservation and dyeing for 90min; then washed with water to obtain reddish-brown wool fabric.

Example 5 Optimization of dye bath pH

The pH in Example 5 was adjusted to 3, 5, 6, and 7, and the others were the same as those in Example 4, to obtain a wool fabric.

The obtained fabric is tested for performance, and the test results are as follows in Table 4:

The test result of table 4 embodiment 5

pH	L*	a*	b*	C*	h°	K/S(440nm)
3	37.61	20.25	27.11	33.84	53.24	16.69
4 (Example 4)	33.72	19.69	21.99	31.77	47.31	17.87
5	35.84	22.38	22.75	31.91	45.47	15.52
6	37.88	21.10	21.75	30.31	45.87	12.61
7	40.63	19.83	21.14	28.98	46.84	10.03

Figure 6 shows the color of directly dyed wool fabrics with different dye bath pH values. As can be seen from Figure 6, the wool fabrics directly dyed with Neem bark pigments are uniform in color, and the fabrics appear brown. When pH=5, the darkest color of wool fabric can be observed.

The dosage optimization of embodiment 6 dyestuff

The amount of dye in Example 4 was adjusted to 2, 6, 10, 14, 18, 22, 26 o.w.f (%), and the others were the same as those in Example 4 to obtain wool fabric.

The obtained fabric is tested for performance, and the test results are as follows in Table 5:

The test result of table 5 embodiment 6

Comparative Example 4

The neem pigment obtained in Example 1 was dyed with iron pre-mordant: 3% owf FeSO ₄ ·6H ₂ O, the liquor ratio was 1:25, the temperature was 60° C., and the neem pigment was treated for 45 minutes, and the amount of neem pigment was 18% (owf) to obtain the dyed neem pigment. wool fabric.

Comparative Example 5

Wool fabrics that have not been dyed.

The reddish-brown wool fabric obtained in Example 4 and the wool fabric of Comparative Example 4 are carried out performance test, and the test results are as follows:

Table 6 shows the anti-ultraviolet properties of wool fabrics of Example 4 and Comparative Example 4 before and after dyeing. It can be seen from Table 6 that the UPF value of the dyed wool fabric increases significantly, and the UVA transmittance and UVB transmittance decrease significantly. The dyed wool fabric has enhanced UV resistance compared with the undyed wool fabric. Among them, the maximum UPF value of the wool fabric of Example 4 is 3457.580, which is 24 times higher than that of the undyed wool fabric, and is greater than 3074.050 of the control example 4. At the same time, the UVA transmittance and UVB transmittance of the wool fabric of Example 4 are the smallest, and the anti-ultraviolet performance is the best.

Table 6 Anti-ultraviolet performance of wool fabrics of Example 4 and Comparative Examples 4 and 5 before and after dyeing

example	UPF value	UVA transmittance (%)	UVB transmittance (%)
Comparative Example 5	142.071	5.620	0.210
Example 4	3457.580	0.258	0.020
Comparative Example 4	3074.050	0.324	0.031

Figure 7 shows the fluorescence effect of wool fabrics before and after dyeing; (a) green fluorescence; (b) red fluorescence; (c) blue fluorescence. It can be seen from Figure 7 that the fluorescence brightness of the three colors of the wool fabric of Example 4 is obviously enhanced; the fluorescence brightness of the wool fabric of Comparative Example 4 is obviously weakened compared with that of Example 4.

8 is a histogram of fluorescence intensity of different colors of wool fabrics before and after dyeing; (a) Comparative Example 5; (b) Example 4; (c) Comparative Example 4. As can be seen from Figure 8, the fluorescence intensity of the undyed wool fabric of Comparative Example 5 is relatively weak, and the fluorescence intensity of Example 4 is significantly increased, wherein the red fluorescence intensity is the largest, the highest fluorescence intensity reaches 214, and the green fluorescence is the strongest up to 198. , the strongest blue fluorescence can reach 112; the fluorescence intensity of control example 4 is significantly reduced, the green fluorescence almost disappears, the red fluorescence intensity can only reach 55, and the blue fluorescence reaches 78.

Table 7 shows the test results of the moth-proof performance of the wool fabric of Example 4. As can be seen from Table 7: the wool fabric after the direct dyeing of Neem bark in Example 4, the visual damage grade is 3C, and the average weight loss is 30mg, while the undyed wool visual damage grade of control example 5 is 4D serious damage, and the average weight loss is 4D. It is 78mg. Although the wool fabric after the direct dyeing of Example 4 is still damaged, the weight loss of the undyed fabric of Comparative Example 5 is reduced by 61.5% and the moth pupation situation is better than that of the undyed fabric of Comparative Example 5, and the anti-moth effect is significantly improved. , Directly dyed wool fabrics have certain anti-moth properties.

Table 7 Mothproof properties of wool fabrics of Example 4 and Comparative Example 5

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone who is familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, The protection scope of the present invention should be defined by the claims.

Claims (12)

1. The application of neem bark pigment in the preparation of multifunctional plush fabric, characterized in that the application is to dye the plush fabric with the neem bark pigment as a dye;

   Wherein, the extraction method of the neem bark pigment comprises the following steps:

   The neem bark powder is added into a mixed solvent of water and ethanol, mixed evenly by a high-speed wall breaker, and extracted at a blade speed of 20,000 to 42,000 r/min; the extraction pH is 9 to 11, and the extraction temperature is 45 to 75 ° C. The extraction time is 10-60 minutes; after extraction, centrifugation, suction filtration, concentration and drying are performed to obtain the neem bark pigment.
2. application according to claim 1, is characterized in that, described dyeing is specifically:

   The method of direct dyeing is adopted, the amount of Neem bark pigment is 18% o.w.f, the liquor ratio is 1:25, the pH of the dyeing bath is 3-5, the dyeing is at room temperature, the heating rate is 2 °C/min, the temperature is raised to the dyeing temperature of 95 °C, and the dyeing is carried out by heat preservation. 90min; then washed with water to remove floating color to obtain multifunctional plush fabric.
3. The application according to claim 1 or 2, characterized in that, the plush fabrics are various plush textiles made of wool, cashmere, and rabbit hair through modern textile technology.
4. The application according to claim 1 or 2, wherein the mass percentage content of ethanol in the mixed solvent is 20-60%.
5. The application according to claim 1 or 2, wherein the mass ratio of the mixed solvent to the neem bark powder is 30-50:1.
6. The application according to claim 1 or 2, characterized in that, in the extraction, the rotation speed of the blade is reduced to 20500 r/min for 50 minutes after the extraction is performed for 10 minutes at a rotational speed of the blade.
7. The application according to claim 1 or 2, wherein the centrifugation adopts a high-speed centrifuge, the rotating speed is 10000r/min, and the centrifugation is performed for 10min.
8. The application according to claim 1 or 2, wherein the particle size of the neem bark powder is 10-20 meshes.
9. The application according to claim 1 or 2, wherein the extraction pH is adjusted by adding a sodium hydroxide solution, and the concentration of the sodium hydroxide solution is 0.95 g/L.
10. The application according to claim 1 or 2, wherein the suction filtration is performed by using a 100nm aperture Buchner funnel and quantitative filter paper for suction filtration.
11. The application according to claim 1 or 2, wherein the concentration is to recover ethanol by rotary evaporation and concentrate the feed liquid, and the solid content of the concentrate is 4.80%.
12. The application according to claim 1 or 2, wherein the drying is freeze-drying, the temperature of freeze-drying is -40°C, and the time is 36h.

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