Method for improving the permeability of pearls using an organic solvent vaporization expansion mechanism

Abstract

The present application belongs to the field of pearl processing, and relates to a method for improving the permeability of pearls by using the vaporization expansion mechanism of organic solvents. The pearls are soaked in the organic solvents at room temperature, the pearls are taken out and put into hot water, the organic solvents are rapidly heated to vaporize, and the pearls are naturally cooled to below 40 DEG C; the process is repeated 2-3 times, the pearls are taken out and put into clean water for standby. The present application combines the vaporization expansion mechanism of organic solvents with the heating mode, first soaks the pearls in the organic solvents, then uses the mode of rapid heating to make the low-boiling-point organic solvents permeated into the deep layer of the pearls rapidly vaporize to generate pressure to extrude the organic matters of the pearl layer and form a large number of small channels to improve the permeability of the pearl layer, which is beneficial to the subsequent boiling of the pearls, and the water can rapidly permeate into the deep layer of the pearls, which lays a foundation for the decomposition of the pearl pigment and the improvement of the pearl bleaching efficiency and bleaching effect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of pearl processing, and relates to a method for improving the bleaching efficiency of pearls, in particular to a method for improving the permeability of pearls by using the vaporization and expansion mechanism of organic solvents. BACKGROUND

[0002] Pearls are loved by people as ornaments because of their white color, color halo, delicate and natural appearance. However, most of the pearls (including natural pearls and cultured pearls) cannot be directly used as ornaments because of defects such as luster, color difference, light and dark, color difference, black spots, and flaws. Therefore, the pearls must be bleached to make them white and transparent, and increase the luster of the pearls to meet the requirements of ornaments.

[0003] Currently, the most common method for bleaching pearls is to first decompose pigments by heating water (commonly known as cooking pearls), and then bleaching with hydrogen peroxide. In most cases, only the cooking step can meet the requirements of ornament pearls. In the cooking step, water needs to penetrate into the interior of the pearls so that the pearl pigments in the interior of the pearls can be dissolved and decomposed in water when heated, and the pearl pigments and undesirable colors can be removed to make the pearls white and transparent.

[0004] The main components of the pearl layer are pearl protein and chitin, and the thickness of the pearl layer is only a few tens of nanometers. However, the structure of the pearl layer is compact, and it is difficult for water to penetrate into the pearl layer during cooking. The process is very slow, the efficiency is low, and the degree of water penetration is low, resulting in unsatisfactory pearl bleaching effect. SUMMARY

[0005] The purpose of the present application is to provide a method for improving the permeability of pearls by using the vaporization and expansion mechanism of organic solvents. Small molecules, low-boiling-point, high-permeability, and hydrophilic organic solvents are used to fully penetrate into the interior of the pearls, and then quickly heated to make the organic solvents vaporize and expand in the pearl layer to generate pressure, thereby extruding many small channels connected to the outside in the pearl layer, which is beneficial to the subsequent penetration of water into the interior of the pearls during cooking, and improves the bleaching efficiency and bleaching effect of the pearls.

[0006] Because the pearl layer is composed of organic matter and has a certain degree of stretchability. Small molecules, low-boiling-point, high-permeability, and hydrophilic organic solvents such as methanol are used to fully penetrate into the interior of the pearls, and then quickly heated to make the organic solvents vaporize and expand in the pearl layer to generate pressure and expel outward, thereby extruding the organic matter of the pearl layer and forming many small channels connected to the outside in the pearl layer, which improves the permeability of the pearl layer and is beneficial to the subsequent penetration of water into the deep layer of the pearls during cooking, and lays the foundation for the decomposition of pearl pigments and the improvement of the bleaching efficiency and bleaching effect of the pearls.

[0007] The technical solutions adopted by the present application are as follows:

[0008] A method for improving the permeability of pearls by using the vaporization expansion mechanism of organic solvents, comprising the following steps:

[0009] Step S1: soaking treatment

[0010] Soak the pearl particles in a small-molecule, low-boiling-point, high-permeability, and hydrophilic organic solvent for 20-48 hours at room temperature.

[0011] Step S2: heating treatment

[0012] Take out the pearl particles and place them in water preheated to 85-100°C, so that the water covers the surface of the pearl particle accumulation, rapidly heat the pearl particles to 100-130°C within 3 minutes, and then continue heating for 3-8 minutes to make the organic solvent vaporize and generate internal pressure; naturally cool to below 40°C, filter, and obtain the pearl particles after preliminary vaporization and extrusion treatment.

[0013] Step S3: repeat the soaking treatment process of step S1 to the heating treatment process of step S2 for 2-3 times.

[0014] Step S4: take out the pearl particles with improved pearl layer permeability after step S3, and place them in clean water for standby.

[0015] Preferably, in step S1, the organic solvent is one or a mixture of methanol, diethyl ether, ethanol, furan, or pyridine. Further, the organic solvent is an organic mixture of methanol and diethyl ether. Still further, in the organic mixture, the volume ratio of methanol to diethyl ether is 100:5-15.

[0016] Preferably, in step S2, the pearl particles are placed in preheated water, the thickness of the pearl particle accumulation is less than 5 cm, and the height of the water covering the surface of the pearl particle accumulation is 1.5-2.5 cm.

[0017] Compared with the prior art, the present application has the following advantages:

[0018] (1) The vaporization expansion mechanism of organic solvents is combined with the heating mode. The pearl particles are first soaked in an organic solvent, and then the low-boiling-point organic solvent that has penetrated into the deep layer of the pearl is rapidly vaporized by the rapid heating mode, generating pressure to extrude the organic matter in the pearl layer and forming a large number of small channels, thereby improving the permeability of the pearl layer and facilitating the rapid penetration of water into the deep layer of the pearl during subsequent pearl cooking, laying a foundation for the decomposition of pearl pigments and improving the efficiency and effect of pearl bleaching.

[0019] (2) The pearl bleaching processing (pearl cooking) time is shortened, the water penetration speed during pearl cooking is greatly improved, the penetration effect is better, and the penetration is more complete.

[0020] (3) Organic solvent is used to vaporize and expand the nacre layer to generate pressure and discharge outward, thereby extruding the organic matter of the nacre layer, forming a large number of micro-channels in the nacre layer, improving the permeability of the nacre layer, enabling water to penetrate into the deep layer of the pearl during pearl boiling, and enabling the pearl pigment to be decomposed to a greater extent, thereby improving the pearl bleaching effect. DETAILED DESCRIPTION

[0021] The specific embodiments of the present application are described in further detail below in conjunction with examples. The following examples are used to illustrate the present application but are not used to limit the scope of the present application. In the following examples, the experimental methods are conventional methods unless otherwise specified. In the following examples, the materials, reagents, etc. are commercially available unless otherwise specified, and among them, analytical reagent is preferred.

[0022] In the examples and the control examples of the present application, the temperature of the pearl particles during the heating process in the microwave oven is measured by an infrared temperature measuring gun. When the temperature of the pearl particles is lower than 100℃, the microwave heating power is appropriately increased so that the temperature of the pearl particles is greater than 100℃. When the temperature of the pearl particles exceeds 130℃, the microwave power should be immediately reduced so that the temperature of the pearl particles is within the range of 100-130℃.

[0023] In the examples and the control examples of the present application, the color grading standards of the pearl particles are as follows: no color is invisible to the naked eye; light color is barely visible to the naked eye; medium color is obviously visible to the naked eye, but the color is obviously light; and dark color is obviously visible to the naked eye, but the color is obviously dark.

[0024] The permeability calculation method is as follows: the permeation area is divided into five grades of 0-25%, 25%-50%, 50%-75%, 75%-100%, and 100%, and the middle number of each grade is taken as a constant (i.e. 12.5%, 37.5%, 62.5%, 87.5%, and 100%, respectively), which is multiplied by the number of pearl particles in the corresponding grade to obtain the permeability of the corresponding grade. Then, the permeability of all corresponding grades is added and divided by the total number of pearl particles to obtain the permeability of the batch of pearl particles.

[0025] Example 1 (pearl particle size 6-7 mm)

[0026] Take 0.5 kg of freshwater pearls with a particle size of 6-7 mm; take 0.3 liters of methanol and 0.03 liters of diethyl ether, mix well, and soak the pearl particles for 24 hours, filter, and take out the pearls, immediately put them into a plastic container with a bottom area of 0.01 square meters within 5 minutes, spread them flat (control the thickness of the pearl particle accumulation to be less than 5 cm), add hot water at 90°C to 2 cm above the pearl particle accumulation surface, then put it into a 1 kw microwave oven within 1 minute to quickly heat the pearl particles to a temperature of 100-130°C. Continue heating for 5 minutes under the condition that the temperature inside the pearl particles is 100-130°C, and then naturally cool to below 40°C, take out the pearl particles. Repeat the above steps to process the pearl particles 2 times. Take out the pearl particles and perform statistical analysis, and divide them into four color grades according to color depth: colorless, light, medium, and dark.

[0027] 0.5 kg of pearl particles were counted, a total of 937, and the statistics are as follows:

[0028] Colorless: 128; light: 294; medium: 340; dark: 175.

[0029] Pearl particle penetration effect verification: In a beaker, add 100 ml of clean water and 1 g of food additive grade lemon yellow, stir well. Take 5 pearl particles from each of the above four grades, a total of 20 pearl particles, and put them into the beaker to dye for 24 hours, take them out and wash them clean. Each pearl particle is ground from one side to half of the remaining pearl particle using a grinder. Observe the color penetration: the center of the ground surface of the 20 pearl particles is dyed yellow, indicating that water can completely penetrate into the pearl layer within 24 hours, and the penetration rate is 100%.

[0030] Boil the pearl bleaching effect verification: the remaining pearl particles are immersed in clean water without interruption, and the water temperature is set to 85-90°C. The results are as follows:

[0031] Colorless: 123, heated to 24 hours, the resulting pearl particles were all colorless, the pearl particles were complete, and the luster was slightly dark.

[0032] Light: 289, heated to 24 hours, there was a faint color; heated to 48 hours, the resulting pearl particles were all colorless, the pearl particles were complete, the luster was bright, and the transparency was good.

[0033] Medium: 335, heated to 48 hours, a faint color was visible; heated to 72 hours, the resulting pearl particles were all colorless, the pearl particles were complete, the luster was bright, and the transparency was good.

[0034] Dark: 170, heated to 72 hours, a faint color was visible; heated to 120 hours, 136 of the resulting pearl particles were colorless, the pearl particles were complete, the luster was bright, and the transparency was good.

[0035] The statistics show that 883 pearls reached the complete decolorization standard within 120 hours, and the complete decolorization rate reached 96.3%.

[0036] Example 2 (Pearl size 10-11 mm)

[0037] Take 0.5 kg of seawater pearls with a particle size of 10-11 mm; soak the pearls in 0.6 liters of ethanol for 34 hours, filter, and immediately place the pearls in a plastic container with a bottom area of 0.01 square meters within 5 minutes, spread them flat (control the thickness of the pearl pile to be less than 5 cm), add hot water at 95°C to 2.5 cm above the pearl pile, then put it in a 1 kw microwave oven for 1 minute to quickly heat the pearl temperature to 100-130°C. Under the condition that the temperature in the pearl is 100-130°C, continue to heat for 7 minutes, and then naturally cool to below 40°C, take out the pearls. Repeat the treatment of the pearls 3 times according to the above method. Take out the pearls and perform statistical analysis, and divide them into four color grades according to color depth: colorless, light, medium, and dark.

[0038] 0.5 kg of pearls were counted, a total of 621, and the statistics are as follows:

[0039] Colorless: 82; light: 251; medium: 210; dark: 78.

[0040] Pearl penetration effect verification: the verification process is the same as in Example 1. Observe the color penetration: the center of the 20 pearl polishing surface is dyed yellow, indicating that water can completely penetrate into the pearl layer within 24 hours, and the penetration rate is 100%.

[0041] Boil pearl bleaching effect verification: the remaining pearls are immersed in clean water and heated continuously, with the water temperature set at 85-90°C. The results are as follows:

[0042] Colorless: 77, heated to 24 hours, the resulting pearls were all colorless, the pearls were complete, and the luster was slightly dark.

[0043] Light: 246, heated to 24 hours, there was a faint color; heated to 48 hours, the resulting pearls were all colorless, the pearls were complete, the luster was bright, and the transparency was good.

[0044] Medium: 205, heated to 48 hours, there was a faint color; heated to 72 hours, the resulting pearls were all colorless, the pearls were complete, the luster was bright, and the transparency was good.

[0045] Dark: 73, heated to 72 hours, there was a faint color; heated to 120 hours, 48 of the resulting pearls were colorless, the pearls were complete, the luster was bright, and the transparency was good.

[0046] The statistics show that 595 pearls reached the complete decolorization standard within 120 hours, and the complete decolorization rate was 95.8%.

[0047] Example 3 (pearl size 6-7 mm)

[0048] Take 0.5 kg of freshwater pearls with a size of 6-7 mm. Mix 0.5 liters of methanol and 0.07 liters of ether uniformly, and soak the pearls for 24 hours. Filter and take out the pearls, and immediately place them in a plastic container with a bottom area of 0.01 square meters within 3 minutes. Flatten the pearls (control the pile height to be less than 5 cm), add hot water at 85°C to 1.5 cm above the pile surface, and then place it in a 1 kw microwave oven for heating to quickly raise the temperature of the pearls to 100-130°C within 1 minute. Continue heating for 4 minutes when the internal temperature of the pearls is 100-130°C, and then naturally cool to below 40°C. Take out the pearls. Repeat the above steps for 3 times. Take out the pearls and perform statistical analysis. According to the color depth, divide them into four color grades: colorless, light color, medium color, and dark color.

[0049] There are 912 pearls in total, and the grading statistics are as follows:

[0050] Colorless: 102 pearls; light color: 341 pearls; medium color: 322 pearls; dark color: 147 pearls.

[0051] Pearl penetration effect verification: the verification process is the same as example 1. Observe the color penetration: the center of the 20 pearl polishing surface is dyed yellow, indicating that water can completely penetrate into the pearl layer within 24 hours. The penetration rate is 100%.

[0052] Boil pearl bleaching effect verification: the remaining pearls are immersed in clean water and heated continuously, with the water temperature set to 85-90°C. The results are as follows:

[0053] Colorless: 97 pearls, heated for 24 hours and taken out, all the obtained pearls are colorless, the pearls are complete, and the luster is slightly dark.

[0054] Light color: 336 pearls, heated for 24 hours, there is a faint color; heated for 48 hours and taken out, all the obtained pearls are colorless, the pearls are complete, the luster is bright, and the transparency is good.

[0055] Medium color: 317 pearls, heated for 48 hours, the color is faintly visible; heated for 72 hours and taken out, all the obtained pearls are colorless, the pearls are complete, the luster is bright, and the transparency is good.

[0056] Dark color: 142 pearls, heated for 72 hours, the color is faintly visible; heated for 120 hours and taken out, 121 pearls are colorless, the pearls are complete, the luster is bright, and the transparency is good.

[0057] The statistics show that, within 120 hours, 871 pearls reached the complete decolorization standard, and the complete decolorization rate reached 97.6%.

[0058] Control group 1 (without soaking with organic solvent)

[0059] Take 0.5 kg of non-nucleated freshwater pearls with a particle size of 6-7 mm; place them in a plastic container with a bottom area of 0.01 square meters, spread them flat (control the pearl particle accumulation thickness to be less than 5 cm), add hot water at 90°C to 2 cm above the pearl particle accumulation surface, then put it into a 1 kw microwave oven within 1 min to quickly heat the pearl particles to 100-130°C. Under the condition that the temperature in the pearl particles is 100-130°C, continue heating for 5 min, and then naturally cool to below 40°C. Take out the pearl particles and repeat the treatment of the pearl particles 2 times according to the above method. Take out the pearl particles and perform statistical analysis, and divide them into colorless, light, medium, and dark according to the color depth, a total of four color grades.

[0060] 0.5 kg of pearl particles were counted, a total of 941, and the grading statistics were as follows:

[0061] Colorless: 120; light: 316; medium: 317; dark: 188.

[0062] Pearl particle penetration effect verification: the verification process is the same as in Example 1. Observe the color penetration: the center of the 20 pearl particles is not dyed yellow. The yellow area statistics are as follows:

[0063] 7 particles with yellow area less than 25% of the total area, 13 particles with yellow area between 25%-50%, no yellow area exceeding 50%, the penetration rate is 28.8%, much smaller than Example 1.

[0064] Pearl bleaching effect verification: the remaining pearl particles are immersed in clean water, heated continuously, and the water temperature is set to 85-90°C. The results are as follows:

[0065] Colorless: 115, heated to 24h, all the obtained pearl particles were colorless, the pearl particles were complete, and the luster was slightly dark.

[0066] Light: 311, heated to 24h, there was a faint color; heated to 48h, 236 of the obtained pearl particles were colorless, the pearl particles were complete, and the luster was slightly dark.

[0067] Medium: 312, heated to 120h, a faint color was visible; heated to 240h, 65 of the obtained pearl particles were colorless, the pearl particles were complete, and the luster was slightly dark.

[0068] Dark: 183, heated to 240h, 0 were colorless, all had obvious color, the pearl particles were complete, and the luster was slightly dark.

[0069] According to statistics, 416 pearls were completely decolorized in 240 hours, and the complete decolorization rate was 45.2%, which was much lower than that of Example 1.

[0070] Control group 2 (without water heating)

[0071] Take 0.5 kg of non-nuclear freshwater pearls, with a particle size of 6-7 mm; take 0.3 liters of methanol and 0.03 liters of diethyl ether, mix well, and soak the pearls for 24 hours, filter, and take out the pearls, immediately put them into a plastic container with a bottom area of 0.01 square meters within 5 minutes, spread them flat (control the thickness of the pearl accumulation to be less than 5 cm), and then put them into a 1 kw microwave oven for heating to quickly raise the temperature of the pearls to 100-130°C within 1 minute. Continue heating for 5 minutes when the internal temperature of the pearls is 100-130°C, and then naturally cool to below 40°C. Take out the pearls and repeat the treatment according to the above method for 2 times. Take out the pearls and perform statistical analysis, and divide them into four color grades according to color depth: colorless, light color, medium color, and dark color.

[0072] 0.5 kg of pearls were counted, with a total of 955 grains, and the grading statistics were as follows:

[0073] Colorless: 131 grains; light color: 305 grains; medium color: 366 grains; dark color: 153 grains.

[0074] Pearl penetration effect verification: the verification process is the same as Example 1. Observe the color penetration: the center of the polished surface of 20 pearl grains is dyed yellow, and the penetration rate is 100% according to statistical analysis. It shows that water can completely penetrate into the pearl layer within 24 hours, which is consistent with Example 1.

[0075] Pearl bleaching effect verification: the remaining pearl grains are immersed in clean water and heated continuously, with the water temperature set to 85-90°C. The results are as follows:

[0076] Colorless: 126 grains, heated to 24 hours, all the obtained pearl grains were colorless, and under ultraviolet light, 65 pearl grains had obvious cracks on the surface.

[0077] Light color: 300 grains, heated to 24 hours, there was a faint color; heated to 48 hours, all the obtained pearl grains were colorless. Under ultraviolet light, 147 pearl grains had obvious cracks on the surface.

[0078] Medium color: 361 grains, heated to 48 hours, a faint color was visible; heated to 72 hours, all the obtained pearl grains were colorless. Under ultraviolet light, 143 pearl grains had cracks on the surface.

[0079] Dark color: 148 grains, heated to 72 hours, a faint color was visible; heated to 120 hours, 140 grains of the obtained pearl grains were colorless, and 8 grains had a faint color. Under ultraviolet light, 62 pearl grains had obvious cracks on the surface.

[0080] Statistically, within 120h, a total of 927 grains reached the complete decolorization standard, and the complete decolorization rate was 99.1%.

[0081] The comparison with Example 1 shows that without water, the decolorization rate of pearls is not affected, but the cracks in the pearl grains are serious, and statistically, 417 pearl grains have obvious cracks, accounting for 44.6%. This seriously affects the value of pearls.

[0082] Take 0.5 kg of non-nuclear freshwater pearls with a particle size of 6-7 mm; take 0.3 liters of methanol and 0.03 liters of diethyl ether, mix well, and soak the pearl grains for 24 hours, filter, and take out the pearls, immediately put them into a plastic container with a bottom area of 0.01 square meters within 5 minutes, spread them flat (control the accumulation thickness of pearl grains to be less than 5 cm), add 60°C hot water to 2 cm above the accumulation surface of pearl grains, then put it into a 1kw microwave oven within 1 minute to quickly heat the pearl grains to 100-130°C. Under the condition that the internal temperature of the pearl grains is 100-130°C, continue heating for 5 minutes, and then naturally cool to below 40°C. Take out the pearl grains and repeat the treatment according to the above method for 2 times. Take out the pearl grains and perform statistical analysis, and divide them into four color grades according to color depth: colorless, light color, medium color, and dark color.

[0083] 0.5 kg of pearl grains were counted, and the statistical results are as follows:

[0084] Colorless: 124 grains; light color: 290 grains; medium color: 333 grains; dark color: 166 grains.

[0085] Pearl grain penetration effect verification: the verification process is the same as Example 1. Observe the color penetration: 0 grains with yellow area less than 25% of the total area, 3 grains with yellow area between 25%-50%, 10 grains with yellow area between 50%-75%, 7 grains with yellow area more than 75%, and 0 grains with 100% dyeing, the penetration rate is 67.5%. Compared with Example 1, it shows that the temperature of the water is too low, which will affect the penetration effect of the treated pearl grains.

[0086] Boiling pearl bleaching effect verification: the remaining pearl grains are immersed in clean water without interruption, and the water temperature is set to 85-90°C. The results are as follows:

[0087] Colorless: 119 grains, heated to 24h, the obtained pearl grains are all colorless, the pearl grains are complete, bright and shiny, and have good transparency.

[0088] Light color: 285 grains, heated to 24h, there is a faint color; heated to 48h, the obtained 285 pearl grains are colorless, the pearl grains are complete, bright and shiny, and have good transparency.

[0089] Mid color: 328 grains, heated to 48h, faintly visible color; heated to 72h, removed, the resulting 281 grains of pearls were colorless, the pearl grains were complete, bright luster, good transparency.

[0090] Dark color: 161 grains, heated to 72h, color was obvious; heated to 120h, removed, the resulting 73 grains of pearls were colorless. The pearl grains were complete, bright luster, good transparency.

[0091] After statistics, within 120h, the completely decolorized pearl grains were 758 grains, and the complete decolorization rate was 84.9%. Lower than example 1.

[0092] Control group 4 (continuous heating temperature less than 100°C)

[0093] Take 0.5kg of non-nuclear freshwater pearl, particle size 6-7mm; take 0.3 liters of methanol, 0.03 liters of diethyl ether, mix well, soak the pearl grains for 24 hours, filter, take out the pearls, immediately put into a plastic container with a bottom area of 0.01 square meters within 5 minutes, lay flat (control the accumulation thickness of pearl grains less than 5cm), add 90°C hot water to 2cm above the pearl grain accumulation surface, then put into a 0.6kw microwave oven within 1 minute to quickly heat the pearl grains to 60-80°C. Under the condition that the temperature inside the pearl grains is 60-80°C, continue to heat for 5 minutes, then naturally cool to below 40°C. Take out the pearl grains, repeat the treatment of the pearl grains according to the above method 2 times. Take out the pearl grains, repeat the treatment of the pearl grains according to the above method 2 times. Take out the pearl grains and conduct statistical analysis, according to the color depth, divide into colorless, light color, mid color, dark color, a total of four color grades.

[0094] After statistics, 957 grains of 0.5kg pearl grains were divided into the following grades:

[0095] Colorless 135 grains; light color 312 grains; mid color 347 grains; dark color 163 grains.

[0096] Pearl grain penetration effect verification: the verification process is the same as example 1. Observe the color penetration: 0 grains of yellow area account for less than 25% of the total area, 2 grains of yellow area account for 25%-50%, 11 grains of yellow area account for 50%-75%, 7 grains of yellow area account for 75%-100%, 0 grains reach 100%, the penetration rate is 68.8%. Compared with example 1, it shows that reducing the heating microwave power will affect the penetration effect of the treated pearl grains.

[0097] Boil pearl bleaching effect verification: the remaining pearl grains are immersed in clean water, heated continuously, and the water temperature is set to 85-90°C. The results are as follows:

[0098] Colorless: 130 pearls, heated for 24h, all the obtained pearls were colorless, the pearls were complete, bright and had good transparency.

[0099] Light color: 307 pearls, heated for 36h, color was faintly visible; heated for 60h, all the obtained pearls were colorless, the pearls were complete, bright and had good transparency.

[0100] Medium color: 342 pearls, heated for 60h, color was faintly visible; heated for 96h, 286 pearls were colorless, the pearls were complete, bright and had good transparency.

[0101] Dark color: 158 pearls, heated for 120h, color was visible; heated for 160h, 0 pearls were colorless, the pearls were complete, bright and had good transparency.

[0102] It was found that 723 pearls reached the complete decolorization standard within 160h, and the complete decolorization rate was 77.2%. Control group 5 (continuous heating temperature greater than 130°C)

[0103] 0.5kg of non-nuclear freshwater pearls with a particle size of 6-7mm were taken; 0.3 liters of methanol and 0.03 liters of diethyl ether were mixed uniformly and soaked in the pearls for 24 hours, then filtered and the pearls were taken out and immediately placed in a plastic container with a bottom area of 0.01 square meters within 5 minutes, spread flat (control the accumulation thickness of the pearls to be less than 5cm), add hot water at 90°C to 2cm above the accumulation surface of the pearls, then put it into a microwave oven with a power of 3kw within 1 minute to quickly heat the temperature of the pearls to 140-150°C. Under the condition that the internal temperature of the pearls is 140-150°C, continue to heat for 5 minutes, and then naturally cool to below 40°C. Take out the pearls and repeat the treatment of the pearls twice according to the above method. Take out the pearls and repeat the treatment of the pearls twice according to the above method. Take out the pearls and perform statistical analysis, and divide them into colorless, light color, medium color and dark color according to the color depth, a total of four color grades.

[0104] 0.5kg of pearls were counted, a total of 949 pearls, the grading statistics are as follows:

[0105] Colorless: 125 pearls; light color: 297 pearls; medium color: 366 pearls; dark color: 161 pearls.

[0106] Pearl penetration effect verification: the verification process is the same as in Example 1. Observe the color penetration: the center of the 20 pearl polishing surfaces is dyed yellow, and the penetration rate is 100% by statistics. It shows that water can completely penetrate into the pearl layer within 24h.

[0107] Pearl bleaching effect verification: the remaining pearls are immersed in clean water and heated continuously, and the water temperature is set to 85-90°C. The results are as follows:

[0108] Colorless: 120 grains, heated to 24h, all the resulting pearls were colorless, 73 grains had cracks on the surface of the pearls, bright luster, good transparency.

[0109] Light color: 292 grains, heated to 24h, color was barely visible; heated to 48h, all the resulting pearls were colorless, 154 grains had cracks on the surface of the pearls, bright luster, good transparency.

[0110] Medium color: 361 grains, heated to 48h, color was barely visible; heated to 72h, all the resulting pearls were colorless, 186 grains had cracks on the surface of the pearls, bright luster, good transparency.

[0111] Dark color: 156 grains, heated to 72h, color was barely visible; heated to 120h, 156 grains of the resulting pearls were colorless, 62 grains were intact, bright luster, good transparency.

[0112] According to statistics, within 120h, 929 grains of pearls reached the complete decolorization standard, with a decolorization rate of 100%. However, when the microwave heating power was increased to 3kw, the intact rate of the pearls was only 48.9%, and more than half of the pearls had surface damage.

[0113] Control group 6 (microwave heating time less than 3min)

[0114] Take 0.5kg of non-nucleated freshwater pearls with a particle size of 6-7mm; mix 0.3 liters of methanol and 0.03 liters of diethyl ether, then soak the pearls for 24 hours, filter, and immediately place the pearls in a plastic container with a bottom area of 0.01 square meters within 5 minutes, spread them flat (control the accumulation thickness of the pearls to be less than 5cm), add hot water at 90°C to 2cm above the accumulation surface of the pearls, then place them in a 1kw microwave oven for heating to quickly raise the temperature of the pearls to 100-130°C within 1 minute. Continue heating for 2 minutes when the internal temperature of the pearls is 100-130°C, then naturally cool to below 40°C. Take out the pearls, repeat the treatment according to the above method for 2 times. Take out the pearls, and statistically analyze them according to the color depth, which is divided into colorless, light color, medium color, and dark color, a total of four color grades.

[0115] There were a total of 946 grains of 0.5kg pearls, and the grading statistics were as follows:

[0116] Colorless: 125 grains; light color: 298 grains; medium color: 343 grains; dark color: 180 grains.

[0117] Pearl penetration effect verification: the verification process is the same as Example 1. The color penetration is observed: 0 particles with yellow area less than 25% of the total area, 2 particles with yellow area between 25%-50%, 14 particles with yellow area between 50%-75%, 4 particles with yellow area between 75%-100%, and 0 particles reaching 100%, with a penetration rate of 65.0%. Compared with Example 1, it shows that shortening the microwave heating time will affect the penetration effect of the treated pearls.

[0118] Boiling pearl bleaching effect verification: the remaining pearls are immersed in clean water, heated continuously, and the water temperature is set to 85-90°C. The results are as follows:

[0119] Colorless: 120 particles, heated for 24h, the obtained pearls are all colorless, complete, bright, and good transparency.

[0120] Light color: 293 particles, heated for 24h, there is a slight color; heated for 48h, the obtained pearls are all colorless, complete, bright, and good transparency.

[0121] Medium color: 338 particles, heated for 48h, there is a slight color; heated for 72h, 301 particles are colorless, complete, bright, and good transparency.

[0122] Dark color: 175 particles, heated for 72h, there is a slight color; heated for 120h, 73 particles are colorless, complete, bright, and good transparency.

[0123] After statistics, there are 787 colorless pearls in 120h, with a complete decolorization rate of 85.0%, which is significantly lower than Example 1.

[0124] Control group 7 (microwave heating time greater than 8min)

[0125] Take 0.5kg of non-nucleated freshwater pearl, particle size 6-7mm; take 0.3 liters of methanol and 0.03 liters of diethyl ether, mix well, soak the pearls for 24 hours, filter, and immediately put the pearls into a plastic container with a bottom area of 0.01 square meters within 5 minutes, spread flat (control the accumulation thickness of the pearls to be less than 5cm), add 90°C hot water to 2cm above the accumulation surface of the pearls, then put it into a 1kw microwave oven within 1 minute to quickly heat the temperature of the pearls to 100-130°C. Continue to heat for 16 minutes when the internal temperature of the pearls is 100-130°C, then naturally cool to below 40°C. Take out the pearls and repeat the treatment according to the above method for 2 times. Take out the pearls and perform statistical analysis, divide them into colorless, light color, medium color, and dark color according to the color depth, a total of four color grades.

[0126] 0.5 kg of pearl grains, a total of 966 grains, were statistically classified as follows:

[0127] Colorless: 135 grains; light color: 327 grains; medium color: 349 grains; dark color: 155 grains.

[0128] Pearl grain penetration effect verification: the verification process was the same as in Example 1. The color penetration was observed: the centers of 20 pearl grains were dyed yellow, and the penetration rate was 100% by statistics. It showed that water could completely penetrate into the pearl layer within 24 hours.

[0129] Boil pearl bleaching effect verification: the remaining pearl grains were immersed in clean water, heated continuously, and the water temperature was set to 85-90°C. The results were as follows:

[0130] Colorless: 130 grains, heated for 24 hours, all the obtained pearl grains were colorless, 121 pearl grains were complete, bright and shiny, and had good transparency; 9 pearl grains had surface cracks.

[0131] Light color: 322 grains, heated for 24 hours, there was a faint color; heated for 48 hours, all the obtained pearl grains were colorless, 314 pearl grains were complete, bright and shiny, and had good transparency; 8 pearl grains had slight surface cracks.

[0132] Medium color: 344 grains, heated for 48 hours, the color was barely visible; heated for 72 hours, 344 pearl grains were colorless, 319 pearl grains were complete, bright and shiny, and had good transparency; 25 pearl grains had slight surface cracks.

[0133] Dark color: 150 grains, heated for 72 hours, the color was barely visible; heated for 120 hours, 145 pearl grains were colorless, 141 pearl grains were complete, bright and shiny, and had good transparency; 9 pearl grains had surface cracks.

[0134] According to statistics, within 120 hours, 941 grains were colorless, and the complete decolorization rate was 99.5%. A total of 51 pearl grains had surface cracks, and the rate of pearl surface cracks was 5.4%. Compared with Example 1, the longer the microwave heating time, the more likely it was to cause damage to the pearl surface and reduce the quality of pearl commodities.

[0135] Control group 8 (only 1 heating and vaporization process was implemented)

[0136] Take 0.5 kg of non-nuclear freshwater pearls, 6-7 mm in size; take 0.3 liters of methanol and 0.03 liters of diethyl ether, mix well, and soak the pearl particles for 24 hours, filter, and take out the pearls, immediately put them into a plastic container with a bottom area of 0.01 square meters within 5 minutes, spread them flat (control the thickness of the pearl particle accumulation to be less than 5 cm), add hot water at 90°C to 2 cm above the pearl particle accumulation surface, then put it into a 1 kw microwave oven within 1 minute to heat the pearl particles to quickly raise the temperature to 100-130°C. Continue heating for 5 minutes when the temperature inside the pearl particles is 100-130°C, and then naturally cool to below 40°C. Take out the pearl particles and perform statistical analysis, and divide them into four color grades according to color depth: colorless, light, medium, and dark.

[0137] 0.5 kg of pearl particles have a total of 919 particles, and the grading statistics are as follows:

[0138] Colorless: 121 particles; light: 285 particles; medium: 337 particles; dark: 176 particles.

[0139] Pearl particle penetration effect verification: the verification process is the same as in Example 1. Observe the color penetration: 0 particles with yellow area less than 25% of the total area, 2 particles with yellow area between 25%-50%, 6 particles with yellow area 50%-75%, 10 particles with yellow area 75%-100%, and 2 particles reaching 100%, with a penetration rate of 76.3%. Compared with Example 1, it shows that only one implementation of methanol instantaneous vaporization expansion and extrusion will affect the penetration effect of the treated pearl particles.

[0140] Boil pearl bleaching effect verification: the remaining pearl particles are immersed in clean water without interruption, and the water temperature is set to 85-90°C. The results are as follows:

[0141] Colorless: 116 particles, heated for 24 hours, and the resulting pearl particles were all colorless, complete, bright, and transparent.

[0142] Light: 280 particles, heated for 24 hours, with a faint color; heated for 48 hours, and the resulting pearl particles were all colorless, complete, and slightly darker in luster than Example 1.

[0143] Medium: 332 particles, heated for 48 hours, with a faint color; heated for 72 hours, and the resulting pearl particles were 304 colorless, complete, and slightly darker in luster than Example 1.

[0144] Dark: 171 particles, heated for 72 hours, with a faint color; heated for 120 hours, and the resulting pearl particles were 116 colorless, complete, and slightly darker in luster than Example 1.

[0145] Statistics show that within 120h, a total of 836 pearls reached the complete decolorization standard, with a complete decolorization rate of 90.8%, which is significantly lower than that of Example 1.

[0146] Control group 9 (heating and vaporization process performed more than 3 times)

[0147] Take 0.5 kg of non-nucleated freshwater pearls with a particle size of 6-7 mm; take 0.3 liters of methanol and 0.03 liters of diethyl ether, mix well, and soak the pearl particles for 24 hours, filter, and take out the pearls, immediately put them into a plastic container with a bottom area of 0.01 square meters within 5 minutes, lay them flat (control the thickness of the pearl particle accumulation to be less than 5 cm), add hot water at 90°C to 2 cm above the pearl particle accumulation surface, then put it into a 1 kw microwave oven within 1 minute to quickly heat the pearl particles to a temperature of 100-130°C. Under the condition that the temperature inside the pearl particles is 100-130°C, continue heating for 5 minutes, and then naturally cool to below 40°C. Take out the pearl particles and repeat the treatment according to the above method 4 times. Take out the pearl particles and perform statistical analysis, and divide them into colorless, light, medium, and dark according to color depth, a total of four color grades.

[0148] 0.5 kg of pearl particles were counted a total of 952, and the grading statistics were as follows:

[0149] Colorless: 129 particles; light: 301 particles; medium: 348 particles; dark: 174 particles.

[0150] Pearl particle penetration effect verification: the verification process is the same as Example 1. Observe the color penetration: the center of the 20 pearl particles is dyed yellow, and the penetration rate is 100% according to statistical analysis.

[0151] It shows that water can completely penetrate into the pearl layer within 24h.

[0152] Pearl bleaching effect verification: the remaining pearl particles are immersed in clean water, heated continuously, and the water temperature is set to 85-90°C. The results are as follows:

[0153] Colorless: 124 particles, heated to 24h, the resulting pearl particles were all colorless, the pearl particles were complete, bright and shiny, and had good transparency.

[0154] Light: 296 particles, heated to 24h, there was a faint color; heated to 48h, the resulting pearl particles were all colorless, the pearl particles were complete, bright and shiny, and had good transparency.

[0155] Medium: 343 particles, heated to 48h, there was a faint color; heated to 72h, the resulting pearl particles were all colorless, the pearl particles were complete, bright and shiny, and had good transparency.

[0156] Dark color: 169 grains, heat to 72h, faintly visible color; heated to 120h, removed, the resulting 161 pearl grains colorless, pearl grain integrity, bright luster, good transparency.

[0157] Statistics, within 120h, a total of 924 pearls to achieve complete decolorization standards, complete decolorization rate of 99.1%, slightly higher than example 1. It is proved that the method provided by the present application can improve the permeability of pearls, and is conducive to improving the processing effect of pearls. But the implementation of more than a certain number of benefits is not great.

[0158] Compared with the existing mode of simply using organic solvents and water agents combined with chemical permeation treatment of pearl grains, the present application uses low-boiling point organic solvents to first penetrate into the pearl layer, and then through heating, the organic solvent is rapidly vaporized and expanded, the pressure generated by the elastic and stretchable organic matter such as protein and chitin between the pearl layers is extruded, a large number of small interconnected pores are formed, thereby laying a foundation for the subsequent water rapid penetration into the pearl layer during the pearl boiling process, promoting the thermal decomposition of pearl pigment, and improving the luster of pearls, thereby improving the processing effect of pearls. In the heating process, the internal temperature of the pearl grains is maintained at 100-130℃, while the external surface of the pearl grains is cooled by hot water to control the temperature not higher than 100℃, to avoid the surface temperature of the pearl grains being too high, which is easy to damage the surface of the pearl layer, at the same time, the water absorbs the organic solvent gas sprayed outside the pearl layer, to avoid the surface pressure of the pearl grains being too large, causing the surface of the pearl grains to crack.

[0159] The above only describes the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and refinements can be made, which should also be considered as the protection scope of the present application.

Claims

1. A method for improving the permeability of pearls by using an organic solvent vaporization expander mechanism, characterized by, The method comprises the following steps: Step S1: soaking treatment The pearl particles are soaked in a small-molecule, low-boiling-point, high-osmotic, and hydrophilic organic solvent at room temperature for 20-48 hours; the organic solvent is an organic mixture of methanol and diethyl ether; in the organic mixture, the volume ratio of methanol to diethyl ether is 100:5-15; Step S2: heating treatment The pearl particles are taken out and put into water preheated to 85-100°C, so that the water covers the accumulation surface of the pearl particles, rapid heating is performed to make the interior of the pearl particles reach 100-130°C within 3 minutes, and then continuous heating is performed for 3-8 minutes to make the organic solvent vaporize to generate internal pressure; natural cooling is performed to below 40°C, filtration is performed, and the pearl particles subjected to preliminary vaporization and extrusion treatment are obtained; Step S3: repeating the soaking treatment process of step S1 and the heating treatment process of step S2 for 2-3 times; Step S4: the pearl particles subjected to the improvement of the permeability of the pearl layer in step S3 are taken out and put into clean water for standby.

2. The method of claim 1, wherein: In the step S2, the thickness of the accumulation of the pearl particles in the preheated water is less than 5 cm, and the height of the water covering the accumulation surface of the pearl particles is 1.5-2.5 cm.