JP6143991B1 - Method for producing colored pearls and colored pearls obtained thereby - Google Patents

Abstract

(a) A non-oxidizing solution containing a leuco body of at least one dye selected from the group consisting of a vat dye and a sulfur dye in an aqueous solvent at a rate of 5 to 400 g) / L in terms of dry weight A step of immersing the pearl in a temperature atmosphere of 0 to 60 ° C. for 1 hour or longer in a neutral atmosphere, and (b) a pearl taken out of the dye solution after a predetermined immersion time, and a temperature condition of 0 to 60 ° C. in an oxidizing atmosphere A method for producing a colored pearl, comprising a step of performing oxidation treatment for 1 hour or more below and repeating the steps (a) and (b) a plurality of times. A colored pearl is obtained by applying a specific coloring without impairing the properties of the pearl layer such as gloss inherent in the pearl.

Description

  The present invention relates to a method for producing a colored pearl and a colored pearl obtained thereby. More specifically, the present invention relates to a technology that can increase the commercial value of pearls by applying a specific color without impairing the inherent properties of natural or cultured pearls such as gloss and denseness.

  As is well known, for example, pearls can be obtained naturally or by aquaculture using seafood such as pearl oysters, white butterflies, black butterflies, mussels, and mussels, or freshwater shellfish such as kawashinjugai, mussels and mussels. Its unique luster and texture are useful, and it has been highly popular as a decorative item since ancient times.

  About 95% of the pearl component is calcium carbonate, and the pearl layer formed on the surface of the pearl layer has a layered structure in which a thin layer of calcium carbonate crystals with a thickness of about 0.2 to 0.5 μm overlaps more than 1000 layers. ing. When light strikes this surface, a phenomenon called “multilayer film interference” occurs inside the translucent layer, resulting in a beautiful pink interference color. There is a protein (conquiorin) layer of about 0.1 μm between the crystal layers of calcium carbonate and plays a role of adhesion. Among these, pigments such as yellow in the case of pearl oyster, black mussel May contain brown, etc., and gold and black pearl black pearls appear to have a color of this pigment accumulation. In addition, the organic matter may be deposited before the cells of the pearl bag secrete the pearl. Blue pearls are the ones that appear as colored in the lowest part of the nacre. The color of the pearl is actually determined by the complicated relationship between the light interference, the pigment and the organic matter as described above.

  By the way, in general, the collected pearls that do not require any processing are 10% or less of the whole, and the rest have very low market value unless some processing is performed. That is, the majority of the pearls that have been collected often have stains due to the contamination of impurities, and the appearance is quite ugly. For this reason, for example, in the case of Akoya pearls, there is also the meaning of color matching, including flower pearls that originally do not require processing, and almost all of them are used for processing.

  Such pearl processing methods generally include primary processing including steps such as pretreatment (drilling), spot removal and bleaching, toning, polishing, and final selection, and then, if necessary, continuous pearls, threading, etc. Secondary processing.

  As mentioned above, the pearl layer that forms the surface of the pearl is composed of multiple layers of calcium carbonate, so it is very difficult to infiltrate the bleaching solution and dye from the surface of the pearl. The processed pearls cannot be processed as they are. For this reason, in the primary processing of pearls, conventionally, for example, a single hole, a double hole, a sleek alterer, and the like are drilled in accordance with the purpose of use of the pearl after first being thoroughly washed.

  Toning is performed in order to align pearls of the same color by dyeing perforated and bleached pearls with a dye. However, the conventional dyeing with pearl dyes generally uses a process of mild tint called rose tint, and does not dye a desired color in a dark color.

  On the other hand, with the recent diversification of customer preferences and the diversification of jewelry design variations, pearls are required to be colored not only in their original colors but also in any color.

  As a method for coloring a pearl, for example, as disclosed in Patent Document 1, a method of performing culture using a core colored in advance as a core to be put into a mother shell, for example, as disclosed in Patent Document 2, a pigment is used. There is also known a method of coating a pearl surface with a synthetic resin paint containing acryl resin and acrylic resin. However, as in Patent Document 1, even if the culturing is performed using a colored core, the obtained pearl cannot be expected to exhibit the desired color. Problems such as spots remain. Further, in the method of forming a colored coating layer as in Patent Document 2, the original luster, texture, etc. of the pearl are completely lost, and the coating layer peels off relatively easily in a short period of time. The possibility is high, and high quality products cannot be obtained.

Also known is a method in which a pearl is immersed in a silver salt solution such as silver nitrate or silver chloride and then colored by irradiating with ultraviolet light or a reducing agent. A reduction reaction occurs between the solution and conchiolin, and silver is deposited. The pearl is completely blackened as a result of innumerable microscopic erosion holes in the pearl layer and silver being deposited therein. However, this method is a method for coloring black pearls and cannot form other shades.

As a technique for coloring pearls using a dye, Patent Document 3 further describes a water-soluble composition comprising a cationic dye, a cationic surfactant, and a nonionic surfactant, having a pH of 5 to 9 and a temperature of 60 to 60. A method for exhausting pearls under 95 ° C conditions is disclosed. According to this document, it is said that by using a cationic dye, a protein layer (conchiolin) existing between the crystal layer of calcium carbonate in the nacre can be efficiently dyed.

However, in this method, exhaust dyeing is performed with a relatively high temperature solution, so that conchiolin is denatured, and the layered structure of the nacreous layer becomes brittle and easily peeled off, which may reduce the quality of the nacreous. In addition, since the cationic dye is ion-bonded to the protein of the conchiolin layer and dyed, the pearl is perforated prior to dyeing so that the dye solution can reach the inside of the nacre. If not set, the dyeing is substantially difficult.

  In addition, as shown in Patent Documents 4 and 5, there is also known a method in which an alcohol is used as a solvent and the dye solution is infiltrated and then the process of heating to a predetermined temperature at which the solvent component volatilizes is repeated a plurality of times. It is assumed that the use of alcohol as the dye increases the penetrability of the dye solution throughout the pearl and increases the coloring efficiency. However, even in this method, since alcohol is used as a solvent and the treatment is performed at a high temperature, the conchiolin is altered or dissolved, and the laminated structure of the nacreous layer is brittle and easily peeled off, which may reduce the quality of the nacreous. It is very expensive.

JP 60-259135 A JP 2004-73761 A JP 2006-305034 A Chinese Patent Publication CN10574183 Chinese Patent Publication CN10574184

  This invention makes it a subject to provide the manufacturing method of the novel colored pearl which eliminates the trouble in the above prior arts, and the colored pearl obtained by this. Another object of the present invention is to provide a method for producing a colored pearl that can be applied with a specific color without impairing the properties of the pearl layer such as gloss inherent in the pearl, and a colored pearl obtained thereby. To do. Another object of the present invention is to provide a method for producing a colored pearl that can be colored with a sufficiently deep hue without previously perforating the pearl, and a colored pearl obtained thereby. Another object of the present invention is to provide a method for producing a colored pearl capable of producing a colored pearl having a deep indigo color, which is not found in conventional pearls, and a colored pearl obtained thereby.

  In order to solve the above problems, the present inventor has examined the use of vat dyes (vat dyes) and sulfur dyes represented by indigo or indigo as dyes for coloring pearls.

  These vat dyes (vat dyes) and sulfur dyes are widely used as dyes for dyeing cellulose fibers such as cotton yarn, and indigo or indigo in particular because dyes having a unique texture can be obtained. It is a product that is also in high commercial demand. On the other hand, vat dyes (vat dyes) and sulfur dyes are well known to be difficult to dye on synthetic fibers due to their high crystallinity and denseness. It is a low dye. Further, as described above, the pearl has a pearl layer formed by stacking a number of thin layers of calcium carbonate on the surface thereof, and is difficult to dye unless it is subjected to pore opening treatment. From both these viewpoints, there has been no report that vat dyes (vat dyes) and sulfur dyes represented by indigo or indigo are used for pearl dyeing.

  In fact, the present inventor tried to dye pearls using indigo dyes under the conditions used for dyeing ordinary cotton yarns, etc. Even when the oxidation treatment was repeated, the dyeing could not be performed substantially.

  Therefore, as a result of intensive studies and experiments, the inventor has surprisingly found that when a certain concentration of a dye solution of a vat dye (a vat dye) and a sulfur dye is used, a predetermined number of immersion and oxidation treatments are performed. It has been found that pearls can be dyed to the desired color with sufficient color depth by repetition. In addition, according to the method, dyeing is possible without performing pearl opening prior to dyeing, and high temperature conditions, strong acid pH conditions, alcohol that adversely affect pearls during dyeing treatment, alcohol And the use of other organic solvents are not required, and properties such as gloss and denseness inherent in pearls are not impaired. And based on such a new knowledge, it reached | attained this invention.

  The present invention that solves the above problems is as follows. (A) A leuco body of at least one dye selected from the group consisting of a vat dye and a sulfur dye in an aqueous solvent at a rate of 5 to 400 g / L in terms of dry weight. A step of immersing the pearl in the dye solution to be contained in a non-oxidizing atmosphere under a temperature condition of 0 to 60 ° C. for 1 hour or more; and (b) taking the pearl out of the dye solution after a predetermined immersion time, and in an oxidizing atmosphere. A method for producing colored pearls, comprising a step of oxidizing at 0 to 60 ° C. for 1 hour or longer and repeating the steps (a) and (b) a plurality of times.

  As an embodiment of the method for producing a colored pearl of the present invention, in the step (a), a dye solution containing an indigo leuco body in an aqueous solvent at a rate of 25 to 120 g / L in terms of dry weight is used. Includes what you use.

  Moreover, as one Embodiment of the manufacturing method of the colored pearl of this invention, what uses an indigo is contained as at least 1 sort (s) of dyes selected from the group which consists of an above-described vat dye and sulfur dye.

  Moreover, as one Embodiment of the manufacturing method of the colored pearl of this invention, what uses the pearl which has not performed the opening process as a pearl to dye | stain is contained.

  Moreover, as one Embodiment of the manufacturing method of the colored pearl of this invention, what uses the pearl by which the opening process was carried out as a pearl to dye | stain is contained.

  Moreover, as one Embodiment of the manufacturing method of the colored pearl of this invention, what uses a freshwater pearl as a pearl colored with dye and the oxidation process in the said (b) process is performed while rotating a pearl.

  Moreover, as one Embodiment of the manufacturing method of the colored pearl of this invention, after using the Akoya pearl as a pearl colored with dye, repeating the said (a) process and the (b) process in multiple times, 7 pearls are further added. Those provided with a stabilization step of standing for about 30 days to about 30 days are included.

  The present invention for solving the above-mentioned problems is also a pearl dyed with at least one dye selected from the group consisting of vat dyes and sulfur dyes, wherein the pearl surface has a saturation of 2.5 on the Munsell color system. -14 and a lightness of 1.5-9, or a chroma of 1.0-2.0 and a lightness of 8-9, and the dye is in a pearl cross section in a depth region of at least 200 μm from its surface. It is a colored pearl characterized by being present.

  As an embodiment of the colored pearl of the present invention, the dye is indigo, and the pearl surface has a Munsell color system (40 hues) hue value of 7.5 BG to 10 PB, saturation of 2. 5 to 14 and a lightness of 1.5 to 9, or a hue value of 7.5BG to 10PB, a saturation of 1.0 to 2.0, and a lightness of 8 to 9 are included.

  Moreover, as one embodiment of the colored pearl of the present invention, the dye is indigo, and the pearl surface has a Munsell color system (40 hues) hue values of 10B to 5PB, saturation of 2.5 to 14 and lightness 3 to 9 are included.

  Moreover, as an embodiment of the colored pearl of the present invention, one that has not been subjected to hole opening treatment is included.

  In addition, one embodiment of the colored pearl of the present invention includes one that has been subjected to a hole opening treatment.

  According to the method for producing a colored pearl according to the present invention, the pearl can be colored in a deep and deep hue, and since the dyeing is performed under very mild conditions, the pearl may be altered. A colored pearl having good fastness and friction resistance can be obtained without deteriorating its quality. Furthermore, sufficient coloring is possible without performing a hole opening treatment for dyeing, and a higher-quality product can be provided. In particular, when indigo is used as a dye to be used, it is possible to produce colored pearls having a deep indigo color that is not found in conventional pearls, and high commercial added value can be expected. is there.

These are drawings (drawing substitute photograph) which show the dyeing | staining degree in one cross section of the colored pearl obtained in the Example of this invention. These are another drawings (drawing substitute photograph) which show the dyeing | staining degree in one cross section of the colored pearl obtained in the Example of this invention. These are drawings (drawing substitute photograph) which show the dyeing | staining degree in one cross section of the colored pearl obtained in another Example of this invention.

  Hereinafter, the manufacturing method of the colored pearl which concerns on this invention is demonstrated in detail based on the embodiment.

  In the method for producing a colored pearl according to the present invention, the pearl is colored with a vat dye (a vat dye) or a sulfur dye.

(1) Pearls In the present invention, the pearls to be chromosomes are not particularly limited, and various natural or cultured pearls can be used. Although it is not particularly limited, specifically, for example, marine products such as pearl oysters, white butterflies, black and white mussels, and mussels, or freshwater shellfishes such as kawashinjugai, geese butterfly, and mussels are naturally used as mother shellfish. Or what is obtained by aquaculture can be used. Further, in the present invention, the structure of the pearl serving as a chromosome may be one having a pearl nucleus inside the pearl layer, for example, Akoya pearl, or substantially having a pearl nucleus inside. It may be composed only of a pearl layer.

  Also, the quality and size of the pearl is not particularly limited. It may be of a low quality such as Suso or poppy.

  Surprisingly, as a chromosomal pearl, the pearl layer is dense and thick, specifically seawater pearls such as so-called Akoya pearls rather than freshwater pearls. It was found that the high-quality materials that were included showed excellent properties in terms of the properties of the dyeing process, although the total time required for dyeing was longer than that of freshwater pearls. That is, it is generally assumed that the pearl layer in the pearl is dense and thick, and it is difficult to dye because the dye is difficult to enter, but in the method for producing a colored pearl according to the present invention, On the other hand, the pearl layer in the pearl was denser and thicker, but the coloring processability was better. For example, in the oxidation step after the dye soaking step, the entire surface of the pearl can be exposed to the entire pearl without exposing the entire pearl to sufficient and uniform exposure to oxygen and by performing an oxidation treatment while gently rotating the pearl. In addition, after the final completion of dyeing by the repetition of the dye soaking step and the oxidation step, there is more color over time if left standing for a certain period of time. It changed deeply in proportion and stabilized. For this reason, combined with the fact that the gloss (shine) inherent to these high-quality pearls is maintained as it is even after the coloring treatment, the commercial properties of the obtained colored pearls are greatly enhanced.

  Such a coloring tendency is slightly different from that in which the pearl layer is relatively coarse, for example, when a general grade freshwater pearl is used. In the case of freshwater pearls and the like, it is preferable to perform oxidation treatment while gently rotating in the oxidation step after the dye soaking step in order to suppress the occurrence of uneven coloring (coloring) of the pearl, and the final dyeing After the end, even if a certain period of time elapses, there is no event that the color further changes with time at a certain ratio.

  From the viewpoint of good coloring processability as described above, the thickness of the pearl layer (winding) is 0.4 mm or more, particularly 0.5 mm or more, although it is not particularly limited. It is preferable that In general, the upper limit of the thickness of the pearl layer is about 1 mm, but is not particularly limited to this value.

  On the other hand, such high-quality pearls are naturally expensive in price, and as a raw material for colored pearls according to the present invention, it may not necessarily meet the needs of many consumers. Therefore, the quality, size, etc. of the pearl as the raw material are not particularly limited as described above, and may be appropriately selected in consideration of such needs of various consumers.

  Further, the pearl that becomes the chromosome can be white or colored to some extent. In consideration of the color before dyeing, it is possible to obtain the target color and density by adjusting the blending and dyeing time or number of dyes.

The chromosomal pearls can be either washed after being picked up (for example, high quality like pearls), or stained or bleached. good.
When blotting or bleaching is performed, it can be performed according to a conventionally known method. However, since the pearl layer may be somewhat destroyed or deteriorated by the bleaching, the processing should be performed under mild conditions. It is desirable to do. As the stain removal or bleaching treatment, typically, a method using a hydrogen peroxide solution, a method using an alcohol such as ethanol, a photobleaching by irradiation with a fluorescent lamp, a method using these in combination, a bleach accelerator or a pH neutralizer However, it is not particularly limited to these. In the treatment with hydrogen peroxide solution, if the concentration is increased and the reaction temperature is increased, the bleaching effect is naturally increased. However, as described above, the risk of damaging the nacre is increased, so that the limitation is particularly limited. However, it is desirable to carry out the reaction under conditions of an appropriate concentration (up to about 3% by volume) and a reaction temperature (up to about 40 ° C.).

  In addition, when performing stain removal or bleaching treatment, in order to enhance the treatment effect, as a pretreatment as conventionally performed, for example, holes such as one hole, both holes, and a sleek alterer are used in accordance with the purpose of use of the pearl. It is also possible to perform opening. However, as will be described later, in the method for producing a colored pearl according to the present invention, it is possible to sufficiently dye even a pearl that has not been perforated, and thus pretreatment for perforating the pearl is not essential. .

(2) Dye In the present invention, at least one dye selected from the group consisting of a vat dye (a vat dye) and a sulfur dye is used as the dye. These dyes are all water-insoluble dyes, but form a water-soluble leuco body in a reducing atmosphere, impregnate the pearl, which is the chromosome, with an aqueous solution containing the leuco body, and then oxidize. Thus, the original water-insoluble dye is restored and dyed.

  The vat dye (vat dye) and sulfur dye used are not particularly limited, and are appropriately selected in consideration of various performances such as a desired color tone. The dye may be natural or synthetic. Vat dyes (vat dyes) are broadly classified into indigo and anthraquinone types in terms of chemical structure, and may belong to either of them. Specific examples include, but are not limited to, for example, vat dyes (vat dyes), various natural indigo or natural indigo, CI Vat. Blue 1 (indigo), CIVat Blue 4 (indantron) , CI Vat Red 10, CI Vat Red 13, CI Vat Red 24, CI Vat Red 31, CIVat Yellow 2, CIVat Orange 2, CIVat Orange 15, CIVat green 3, CIVat green 7, CIVat green 12 CIVat green 28, CIVat Brown 1, CIVat Brown 6, CIVat Brown 35, CIVat Black 8, CIVat Black 9, CIVat Black 16, and the like. Examples of natural indigo or natural indigo include those derived from various conventionally known plants, such as Persicaria tinctoria, Strobilanthes cusia, Indian indigo (Indigofera suffruticosa), Ward (Isatis tinctoria), It includes but is not limited to Taisei (Isatis indigotica). Examples of sulfur dyes include C.I. sulpher Black 1, C.I. sulpher Green 2, and C.I. sulpher Green 3. In addition, vat dyes (vat dyes) and sulfur dyes may be used alone, or may be used in combination with a plurality of dyes for the purpose of obtaining a desired color tone, or may be used by changing each time. Both vat dyes (vat dyes) and sulfur dyes may be used at the same time.

  Of these vat dyes (vat dyes) and sulfur dyes, indigo (including natural indigo or natural indigo and synthetic indigo) is particularly important. Indigo does not dissolve in water as it is, and has almost no dyeing property to fibers. Therefore, in dyeing with indigo, it is necessary to prepare a leuco body (leucoin digo) by reducing indigo using a reducing agent such as hydrosulfite. This leuco indigo is dissolved in water and has a dyeability to the chromosome. Indigo is dyed as leucoin digo in the sample immediately after the dehydration treatment, and thereafter, it is oxidized by oxygen in the air under an oxidizing atmosphere and returns to its original state (indigo). The structures of indigo and roycoin digo are shown in the following chemical formula.

  The reducing conditions for obtaining the leuco form of the vat dye and sulfur dye as described above are not particularly limited, and can be carried out by any conventionally known method. For example, although not particularly limited, even if using natural indigo or natural indigo (sukumo) ash juice (the main component is calcium carbonate) and using a method of natural ash fermentation construction to obtain a leuco body by fermentation, A method using a chemical building (reducing building) using chemicals as a reducing agent and an alkali agent may be used, or a method combining these may be used.

  As a reducing agent for chemical construction, any known reducing agent can be used, for example, hydrosulfite, thiourea dioxide, sodium sulfide, glucose, hydroxyacetone, dihydroxyacetone, etc. can be used. Of these, hydrosulfite is particularly preferable. In addition, as the alkali agent, any one generally used in dyeing methods with vat dyes can be used, for example, potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium phosphate, sodium phosphate, etc. can do.

  Although not particularly limited, the embodiment using the natural lye fermentation of natural indigo or natural indigo as the leuco body of the vat dye and chemical dye, the obtained colored pearl is the original luster of the pearl, This is one of the particularly preferred embodiments of the present invention because it adds a unique natural deep blue color to the texture and the like, and can be a product that greatly attracts the interest of consumers.

(3) Preparation of dye solution Therefore, in the coloring method of the present invention, the leuco body of at least one dye selected from the group consisting of the above-mentioned vat dyes and sulfur dyes is used as the dye solution. A dye solution is prepared by containing 5 to 400 g / L in terms of conversion, more preferably 20 to 200 g / L, further preferably 25 to 120 g / L, and most preferably 30 to 75 g / L in an aqueous solvent. . In addition, as a dye density | concentration, the pearl which is a chromosomal is the difference between what was subjected to the perforation treatment and the non-perforated one not subjected to the perforation treatment, and the degree of coloring of the colored pearl to be obtained (particularly, It is possible to change the concentration within the above range according to the degree of brightness, etc., and in general, when using a pearl that is a chromosomal subject to perforation, The higher the density is, the lower the density may be.

  As described above, in the present invention, the dye concentration in the dye solution is the same as that in the dye solution used for fiber dyeing with general vat dyes and sulfur dyes (specifically, for example, the leuco body of the dye in terms of dry weight). Compared with 0.5 to less than about 5 to 5 g / L), a certain range with a considerably high concentration is used. That is, if the dye concentration (leuco body content) is lower than the above condition range, even if the contact time with the dye solution and the subsequent oxidation time are extended or the number of treatments is increased, If it is difficult to color the pearls, on the other hand, if it exceeds the above range, not only can the dyeing efficiency be improved even if the concentration is increased further, but also the homogeneity of the dye solution is not improved. This is because it may be difficult to hold and uneven dyeing or the like may easily occur.

  As an aqueous solvent used in preparing the dye solution, water is usually used, but if necessary, a water-soluble organic solvent such as ethanol or the like as long as it does not adversely affect chromosomal pearls. It is possible to add a solvent or the like. Moreover, it is also possible to mix | blend various surfactant as needed. The addition of a surfactant can be expected to improve the dyeing efficiency by improving the contact between the dye molecule and the pearl.

  The dye solution is prepared by diluting a stock solution prepared in advance with a leuco body of at least one dye selected from the group consisting of the vat dye and sulfur dye as described above to a predetermined concentration with water. It is also possible to prepare the leuco body or to continuously perform the steps from the preparation of the leuco body to the dye solution having a predetermined concentration.

  The water used, particularly when diluting the dye leuco body stock solution, is preferably deoxygenated so that the leuco body of the dye is not oxidized and insolubilized. Although it does not specifically limit, in order to stabilize a leuco body, ie, to reduce | restore the leuco body which becomes oxidized in a dye bath, hydrosulfite is 0.1-5 g / l, for example. More preferably, it is desirable to add an excess of about 0.2 to 2 g / l. Instead of hydrosulfite, other suitable reducing agents, such as glucose or hydroxyacetone, or a combination of various other reducing agents can be used. Moreover, in order to improve dye solubility, it is also possible to heat appropriately or add hot water (for example, about 50-60 degreeC) suitably. Moreover, in order to maintain a reduced state, it is also possible to add an appropriate amount of an alkali agent such as sodium hydroxide as necessary.

(4) Dye soaking step In the method for producing colored pearls according to the present invention, the pearl as the chromosome as described above is lightly washed as necessary, and (a) prepared at a predetermined concentration as described above. It is immersed in the vat dye and sulfur dye thus obtained for 1 hour or more under a temperature condition of 0 to 60 ° C. in a non-oxidizing atmosphere.

  In the present specification, “under non-oxidizing atmosphere” means that the oxidation of the leuco form of the vat dye or sulfur dye contained in the dye solution does not proceed as much as possible. However, it is not limited to the narrow meaning of an atmosphere in which no occurs. Specifically, for example, as a non-oxidizing atmosphere, an atmosphere using an inert gas such as nitrogen or argon (which may contain a certain amount of air) or a dye solution and pearls are stored. For example, a flexible bag made of synthetic resin such as polyethylene or polypropylene is used as the container body, and after storing the dye solution and the pearl, the bag is squeezed out to remove the air and sealed. The mode of performing is exemplified.

  The pearl immersion time depends on the size of the pearl to be dyed, the presence or absence of pearl opening, and the temperature of the dye solution, but is at least 1 hour, preferably 6 hours to 2 days, more preferably It is about 12 to 24 hours. In general, the larger the size of the pearls and the less the pearls are perforated, the more difficult the dyeing proceeds, and it is desirable to extend the immersion time accordingly.

  Moreover, as temperature conditions of the dye solution at the time of a pearl immersion treatment, it is 0-60 degreeC, More preferably, it is 10-50 degreeC, More preferably, it is about 15-25 degreeC. Thus, in this invention, since the very mild conditions near normal temperature are used as the temperature conditions at the time of immersion, there is very little possibility of damaging the pearl that is the object to be processed. When the temperature of the dye solution exceeds 60 ° C., the leuco body of the dye is likely to be oxidized, and there is a risk that it may be deactivated. On the other hand, when the temperature is less than 0 ° C., the dye solution Is difficult to maintain as a liquid, and the dyeing efficiency of the dye also decreases.

  In this dye soaking process, the pearls may be dyed while still standing, but if necessary, the dye solution or pearls may be moved gently by hand or using an appropriate mechanical device such as a shaking table. It is also possible to perform processing while preventing the occurrence of uneven dyeing. However, if the stirring is too strong, a collision may occur between the pearls or between the pearl and the container wall, which may damage the surface of the pearl layer, and the leuco body of the dye may be easily oxidized. Therefore, it is important to move it gently.

(5) Oxidation step (b) The pearl is taken out from the dye solution after the elapse of a predetermined dipping time in the (a) dye dipping step, and is subjected to an oxidation treatment for 1 hour or more under a temperature condition of 0 to 60 ° C in an oxidizing atmosphere. In addition, since the pearl taken out from the dye solution removes the dye solution adhering excessively prior to the oxidation treatment, it can be washed as necessary.

  The oxidation treatment in an oxidizing atmosphere is not particularly limited as long as it is a method in which an oxidation reaction is advanced by oxygen. From an economic point of view, it is preferable to oxidize with oxygen in the atmosphere, but oxygen may be added to increase the oxygen concentration.

  The temperature condition during the oxidation treatment is 0 to 60 ° C, more preferably 10 to 50 ° C, and still more preferably about 15 to 25 ° C. As described above, in the present invention, since a very mild condition close to room temperature is used as the temperature condition during the oxidation treatment, there is a very low possibility that the pearl that is the object to be treated is damaged.

  The oxidation treatment time is at least about 1 hour or more, preferably about 1 hour to about 7 days, more preferably about 7 hours to about 7 days, and further preferably about 12 hours to about 7 days. The oxidation treatment is important for coloring and insolubilizing the dye by oxidation of the leuco body of the dye, and it is necessary to carry out at least the above time.

  Further, in the oxidation treatment, it is desirable to expose the entire pearl to oxygen sufficiently and uniformly, and on this, it is desirable to perform the oxidation treatment while rotating the pearl. In addition, the pearl used as a chromosome has a dense pearl layer as described above, and has a thickness (winding) of 0.4 mm or more, particularly a thick one of 0.5 mm or more. In this case, for example, seawater pearls such as Akoya pearls, and even high-quality pearls containing pearls, the pearls can be evenly distributed without performing such a rotation operation during oxidation treatment. Dyeing is possible. Of course, even when such a high quality pearl is used, it is possible to perform such a rotation operation itself. Therefore, for example, in an embodiment in which a pearl having a relatively coarse pearl layer is used as a chromosome, such as a freshwater pearl, such a rotation operation during the oxidation treatment is particularly desired.

  Here, “rotation” is not limited to a strict meaning of rotating a pearl at a certain angle in a certain direction, for example, an angle of a certain degree or more without leaving the pearl stationary, specifically, for example, 10 More than about °, preferably about 30 ° or more, more preferably about 60 ° or more in a broad sense, including all aspects of rotating and rolling pearls irregularly in an indefinite direction. It can be included. Further, the speed of rotation or rotation is not particularly limited as long as it avoids leaving the pearls stationary, and it is sufficient to be loose. Although not particularly limited, generally, for example, about 0.01 rpm or more, more preferably about 0.1 to 10 rpm is sufficient. As described above, not the regular rotation but the irregular rotation or rotation may be used.

(6) Repeating dye immersion step and oxidation step In the pearl coloring method according to the present invention, the above-described (a) dye immersion step and (b) oxidation step are performed a plurality of times, that is, at least twice or more. Preferably it is repeated 3 to 10 times, more preferably 3 to 4 times.

  That is, it is a pearl having a small size or a pearl that has been subjected to pore opening treatment, which tends to be colored relatively simply by performing the (a) dye soaking step and (b) oxidation step as described above. However, even with a certain amount of immersion and oxidation time, coloring with vat dyes or sulfur dyes does not substantially occur when washed with water. For example, when indigo dyes are used, Is only slightly yellowish. However, when (a) the dye soaking step and (b) the oxidation step are repeated a plurality of times, it can be confirmed that the coloration rapidly proceeds visually at a certain number of repetitions. More specifically and representatively, for example, almost no coloring occurs after the first (a) dye immersion step and (b) oxidation step, and the second (a) dye immersion step and (b) oxidation step. Even after the first time, coloring does not occur so much, but after the third (a) dye soaking step and (b) oxidation step, the color changes rapidly and the coloring proceeds greatly. When extended, the degree of coloring will be deeper than before. After the time when such a large color change occurs, the color change occurs more easily. Therefore, it is not necessary to repeat the subsequent times, and even if it is repeated, 1 to 2 degrees is sufficient.

  For this reason, the detailed mechanism of action is not clear, but in the pearl coloring method according to the present invention, in any one of the repeated dye soaking and the oxidation treatment, the pearl is It may be considered that structural or surface chemical changes occur and the dyeing is likely to occur.

(7) Post-treatment In the method for producing a colored pearl of the present invention, as described above, the pearl can be colored by repeating (a) the dye soaking step and (b) the oxidation step a predetermined number of times. After the oxidation step, if necessary, it can be subjected to removal of excess adhering dye by soaping, water washing treatment and drying step.

  In addition, as the chromosomal pearl, when the pearl layer is dense and thick, for example, seawater pearls such as Akoya pearls and high quality pearls, the above-described dye soaking process and oxidation process are repeated. After the last round of treatment, or after such post-treatment, if the pearls are left standing for a certain period of time, the color of the colored pearls changes more gradually over time, and a phenomenon is observed that becomes stable. There is. Although not particularly limited, specifically, for example, immediately after the last of the repetition of the dye soaking step and the oxidation step, or immediately after the post-treatment, about 7 days to about 30 days as the final stage, A sufficiently distinguishable color change occurs. Although the degree is not particularly limited, specifically, an increase in the numerical value of about 1 to 4 as the saturation value of the Munsell color system and a decrease in the numerical value of about 1 to 2 as the brightness value ( The color becomes darker).

(8) Colored pearl By the method for producing a colored pearl according to the present invention as described above, the pearl has properties such as gloss and denseness originally possessed by the pearl, but has a deep color that is not expected in the past. Colored pearls are obtained. That is, the colored pearl according to the present invention is a pearl dyed with at least one dye selected from the group consisting of a vat dye and a sulfur dye, and the pearl surface has a saturation of 2.5 on the Munsell color system. -14 and a lightness of 1.5-9, or a chroma of 1.0-2.0 and a lightness of 8-9, and the dye is in a pearl cross section in a depth region of at least 200 μm from its surface. It is characterized by the existence.

  Further, the colored pearl according to a particularly preferred embodiment of the present invention is a colored pearl dyed with indigo, and the pearl surface has a Munsell color system (40 hues) hue value of 7.5BG to 10PB, Saturation of 2.5 to 14 and lightness of 1.5 to 9, or a hue value of 7.5BG to 10PB, saturation of 1.0 to 2.0, and lightness of 8 to 9. It is a feature.

  Further, the colored pearl according to a further preferred embodiment of the present invention is a colored pearl dyed with indigo, and the pearl surface is a Munsell color system (40 hues) hue values 10B to 10B 5PB, saturation 2.5-14, and lightness 3-9.

  In addition, regarding the colored pearl according to the present invention, the color of the pearl surface is defined by the Munsell color system as described above. The Munsell color system is well known to those skilled in the art as “color display method by three attributes” (JIS Z 8721), and the three attributes of color are hue (H) and lightness (V). The colors are classified according to the saturation (C).

  In the Munsell color system, the hue (H) can be indicated by a combination of a Munsell hue ring symbol (R, Y, G, B, and P) and a number (such as 5 and 10). In the Munsell color wheel, “R” indicates red, “Y” indicates yellow, “G” indicates green, “B” indicates blue, and “P” indicates purple. The intermediate hues “YR” indicate yellow red, “GY” indicates green yellow, “BG” indicates blue green, “PB” indicates purple blue, and “RP” indicates Shows red purple. In the Munsell color system, “10 hues” of the Munsell hue ring is a general term for hues assigned the number “10”. Further, the “20 hue” of the Munsell hue circle is a “20 hue” obtained by adding a number “5” to a hue located in the middle of the “10 hue” of the Munsell hue circle. Further, the “40 hue” of the Munsell hue ring is obtained by adding the number “2.5” or “7.5” to the hue located in the middle of the “20 hue” of the Munsell hue ring.

  In the Munsell color system, the saturation (C) is indicated by a value of 0 to 14, and is an index indicating the vividness of the color. The smaller the value, the clearer the color, and the larger the value, the more the color Indicates vivid. The saturation (C) of the colored pearls according to the present invention is 2.5-14, preferably 5-14.

  In the Munsell color system, lightness (V) is indicated by a value of 0 to 10, and is an index indicating the brightness of the color. The smaller the value, the darker the color, and the higher the value, the brighter the value. . The brightness (V) of the colored pearl according to the present invention is 1.5 to 9, preferably 2.5 to 8.

  When the colored pearl according to the present invention has a high lightness (V), specifically, when the lightness (V) is 8 to 9, the saturation (C) is lower than the above, specifically, The aspect whose degree (C) is 1-2 may also be included. This is because, in the Munsell color system, in the case of high lightness (V), there is a very high saturation (C) value itself.

  The hue (H) of the colored pearl according to the present invention is used in the method for producing a colored pearl as described above, and the vat dye and / or sulfur dye contained in the finally obtained pearl is appropriately changed. In general, by including indigo, particularly natural indigo or natural indigo as a dye, 7.5BG to 10PB in the Munsell hue ring (40 hues) of the Munsell color system It may have a hue (H) from (so-called “blue-green” to “group blue”), more preferably 2.5B to 7.5PB, and even more preferably 10B to 5PB.

  Further, in the colored pearl according to the present invention, as described above, the pearl contains at least one kind of dye selected from the group consisting of a vat dye and a sulfur dye, and exhibits a predetermined color. In the cross section, it exists in a depth region of at least 200 μm from the surface, more preferably a depth region of up to 500 μm, and more preferably at least about 10% of the distance from the surface to the pearl center. Is.

  In general, in a conventionally known pearl dyeing method, a dye enters a gap between the pearl layer on the surface side of the pearl and the pearl nucleus on the center side of the pearl by dyeing the perforated pearl, The color of this dye is transmitted through the pearl layer and is visible from the outside of the pearl, thereby exhibiting a colored form. In the present invention, for example, a cross-sectional photograph of a pearl obtained in the examples described later (FIG. 1, 2), the pearl layer on the surface side is mainly dyed at a sufficient depth, and has a different dyeing form from the conventional one. In particular, when using a pearl that has been perforated as a chromosome, not only the nacreous layer but also the entire pearl cross section is stained, but even in this case, it is the most intensely stained. Is a nacre of sufficient depth from the surface as defined above.

  Furthermore, as a more preferable aspect of the colored pearl according to the present invention, the following are included as some representative examples. Of course, the present invention is not limited to these specific embodiments, and various modifications or changes can be made within the scope of the present invention defined in the claims attached to this specification. Those skilled in the art will readily understand that this is possible.

  A colored pearl according to a preferred embodiment is a colored pearl obtained by dyeing a perforated freshwater pearl with indigo, particularly natural indigo, and the pearl surface has a Munsell color system (40 hues) hue. The value 10BG-5PB, saturation 2.5-12, lightness 1.5-9, and indigo in the pearl cross section at least 200 μm from the surface, preferably at least 500 μm deep. It is characterized by.

  A colored pearl according to another preferred embodiment is an open-sealed sea pearl, preferably a colored pearl obtained by dyeing Akoya pearl with indigo, particularly natural indigo, wherein the pearl surface has a Munsell color system Munsell. The hue ring (40 hues) has a hue value of 10BG to 5PB, a saturation of 2.5 to 12, and a brightness of 1.5 to 9, and indigo is at least 200 μm from the surface in the pearl cross section, preferably at least 500 μm It exists in the depth area | region of this.

  A colored pearl according to still another preferred embodiment is a colored pearl obtained by dyeing an unopened freshwater pearl or a seawater pearl with indigo, in particular, natural indigo, and the pearl surface has a Munsell color system with a Munsell color system ( 40 hue) and a hue value of 10BG to 5PB, a saturation of 2.5 to 12, and a brightness of 1.5 to 9, and indigo has a depth of at least 200 μm, preferably at least 500 μm, from its surface in the pearl cross section. It exists in the area.

  Hereinafter, the present invention will be described more specifically based on examples. However, the following examples are merely illustrated for facilitating understanding of the present invention, and the present invention is not limited to these examples.

Example 1
As a leuco body stock solution of indigo dye, natural indigo concentrate (manufactured by Tanaka Naoten Store) is used, and the dye solution is diluted with water so that the leuco body is contained at a rate of 71 g / L in terms of dry weight. About 300 ml was prepared. In addition, at the time of dilution, it adjusted so that liquid temperature might be in the range of 15-25 degreeC using warm water in part. Furthermore, hydrosulfite was added to this diluted water at a rate of 5 g / L for deoxygenation treatment. The prepared dye solution was transferred to a commercially available flexible resin bag with a zipper, and mixed with care so as not to foam as much as possible so as not to touch air.

  On the other hand, 100 pearl pearl oysters with a diameter of 7 mm (both hole-opened) were each lightly washed with water, gently put into a flexible resin bag with a zipper containing the dye solution, and put back. The inside air was discharged outside as much as possible and sealed. In this state, the mixture was allowed to stand at room temperature (20 ± 5 ° C.), and the pearl was immersed in the dye solution for 72 hours. After 72 hours of immersion, the pearls were removed and oxidatively dried in air for 24 hours while slowly falling on a flat plate. After the first immersion and oxidation treatment, the pearl color did not change much.

  Next, the pearl is again put in a flexible resin bag with a zipper containing the same dye solution as described above, and left to stand at room temperature (20 ± 5 ° C.) as described above, and immersed for 72 hours. The pearls taken out as described above were oxidatively dried in air for 24 hours while slowly falling on a flat plate. After the second immersion and oxidation treatment, the color of the pearl hardly changed.

  Furthermore, this pearl is again put in a flexible resin bag with a zipper containing the same dye solution as described above, and is left to stand at room temperature (20 ± 5 ° C.) as described above, immersed for 72 hours, and after the immersion treatment. The pearls taken out as described above were oxidatively dried in air for 24 hours while slowly falling on a flat plate. After the third immersion and oxidation treatment, a great change in pearl color was observed. The colored pearls were finally washed with water and sufficiently dried naturally.

  Although the obtained colored pearl has a slight degree of coloring depending on the individual, the hue value of the Munsell hue ring of the Munsell color system is 2.5 B to 7.5 PB, saturation 5 to 12, brightness 3 to 8. It was in the range.

  Moreover, in the obtained colored pearls, no significant changes were observed in the original luster, stickiness, etc. of the pearls used. This point was the same for any of the following examples.

  Furthermore, the cross section of the obtained colored pearl was observed using an optical microscope (digital microscope KH-8700, manufactured by Hilox Co., Ltd.), and the penetration degree of the dye (indigo) was examined. As a result, the dye penetrated over the entire pearl cross section, and strong dyeing was observed particularly in a region (pearl layer) having a depth of 500 μm or more from the surface.

Example 2
The dyeing treatment was performed in the same manner as in Example 1 except that the pearl was changed to a fresh water pearl of about 5 mm (both holes were subjected to the hole opening treatment).

  Although the obtained colored pearl has a slight degree of coloring depending on the individual, the hue value of the Munsell hue ring of the Munsell color system is 2.5 B to 7.5 PB, saturation 5 to 12, brightness 3 to 8. It was in the range.

  Further, the cross section of the obtained colored pearl was observed in the same manner as in Example 1. The obtained results are shown in FIGS. As a result, as shown in FIGS. 1 and 2, the dye penetrated over the entire pearl cross section, and strong dyeing was observed particularly in a region (pearl layer) having a depth of 500 μm or more from the surface.

Example 3
The dyeing treatment was performed in the same manner as in Example 1 except that the pearl was changed to an unopened freshwater pearl of about 7 mm.
Although the obtained colored pearl has a slight degree of coloring depending on the individual, the hue value of the Munsell color system Munsell hue ring is 7.5B to 7.5PB, saturation 2 to 12, brightness 6 to 8 It was in the range.

  Further, the cross section of the obtained colored pearl was observed in the same manner as in Example 1. The obtained results are shown in FIG. As a result, as shown in FIG. 3, the dye was strongly dyed in a region (pearl layer) having a depth of 500 μm or more from the pearl surface.

Example 4
In Example 3, dyeing treatment was performed in the same manner as in Example 3 except that the immersion time in each dye immersion step was changed to 168 hours.
Although the obtained colored pearl has a slight degree of coloring depending on the individual, the hue value of the Munsell color system Munsell hue ring is 5.0 B to 7.5 PB, saturation 5 to 12, brightness 3 to 6 It was in the range.

Example 5
In Example 3, the dyeing process was performed in the same manner as in Example 3 except that the number of repetitions of the dye soaking step and the oxidation step was changed from 5 to 6.
Although the obtained colored pearl has a slight degree of coloring depending on the individual, the hue value of the Munsell color system Munsell hue ring is 5.0 B to 7.5 PB, saturation 5 to 12, brightness 3 to 6 It was in the range.

Example 6
The dyeing treatment was performed in the same manner as in Example 1 except that the dye solution was prepared so as to contain the leuco body of indigo dye at a rate of 33 g / L in terms of dry weight.
Although the obtained colored pearl has a slight degree of coloring depending on the individual, the hue value of the Munsell color wheel of the Munsell color system is 7.5B to 7.5PB, saturation 5 to 12, and lightness 5.5. It was in the range of ~ 8.

Example 7
The dyeing treatment was performed in the same manner as in Example 1 except that the dye solution was prepared so as to contain the leuco body of indigo dye at a rate of 20 g / L in terms of dry weight.
Although the obtained colored pearl has a slight degree of coloring depending on the individual, the hue value of the Munsell hue ring of the Munsell color system is 2.5 B to 7.5 PB, saturation 5 to 8, brightness 6 to 8 It was in the range.

Example 8
Except that the dye solution was prepared so that the leuco body of indigo dye was contained at a rate of 33 g / L in terms of dry weight, and each immersion treatment time was changed to 48 hours and each oxidation treatment time was changed to 8 to 9 hours. In the same manner as in Example 3, non-perforated freshwater pearls were dyed.
Although the obtained colored pearl has a slight degree of coloring depending on the individual, the hue value of the Munsell hue ring of the Munsell color system is 7.5BG to 10PB, saturation 1.0 to 2.0, lightness 8 It was in the range of -9.

Example 9
The dyeing treatment was performed in the same manner as in Example 1 except that the dye solution was prepared so as to contain the leuco body of indigo dye at a rate of 180 g / L in terms of dry weight.
Although the obtained colored pearl has a slight degree of coloring depending on the individual, the hue value of the Munsell color system Munsell hue ring is 5.0 B to 7.5 PB, saturation 5 to 12, brightness 3 to 6 It was in the range.

Example 10
A natural indigo concentrate (manufactured by Nanaka Tanaka Dye Store Co., Ltd.) is used as the leuco body stock solution of indigo dye, and the dye solution is diluted with water so that the leuco body is contained at a rate of 33 g / L in terms of dry weight About 600 ml was prepared. In addition, at the time of dilution, it adjusted so that liquid temperature might be in the range of 15-25 degreeC using warm water in part like Example 1. FIG. Furthermore, hydrosulfite was added to this diluted water at a rate of 5 g / L for deoxygenation treatment. The prepared dye solution was transferred to a commercially available flexible resin bag with a zipper, and mixed with care so as not to foam as much as possible so as not to touch air.

  On the other hand, high-grade pearl oyster pearls with a diameter of 4.0 to 4.5 mm (“Hana pearls” grade AAA, pearl layer thickness 0.5 mm or more) 55 grains (one-hole-opened) were washed with water. While still wet, the bag was gently put into a flexible resin bag with a zipper containing the dye solution, and the air in the bag was discharged to the outside as much as possible and sealed. In this state, the mixture was allowed to stand at room temperature (20 ± 5 ° C.), and the pearl was immersed in the dye solution for 48 hours. After 48 hours of immersion treatment, the pearls were taken out, allowed to stand on a flat plate and oxidatively dried in air for 8 to 9 hours. After the first immersion and oxidation treatment, the pearl color did not change much.

  Next, this pearl is again put in a flexible resin bag with a zipper containing the same dye solution as described above, and left at room temperature (20 ± 5 ° C.) as described above, and immersed for 48 hours, After the treatment, the step of allowing the pearls taken out as described above to stand on a flat plate and oxidizing and drying in the air for 8 to 9 hours was repeated three more times (four times in total). A great change in the color of the pearls was observed by repeating this immersion and oxidation treatment four times. The colored pearls were finally washed with water and sufficiently dried naturally.

  Although the colored pearls obtained after natural drying have a slight degree of coloring depending on the individual, the hue values of the Munsell color system Munsell hue ring are 10B to 2.5PB, saturation 4 to 8, brightness 7 to It was within the range of 8.

  Furthermore, the obtained colored pearl was put in a sealed polyethylene sachet and allowed to stand, and it was observed whether or not the color of the pearl was changed. As a result, surprisingly, the color of the colored pearl changed to a deeper shade in the period of about 7 days to 4 weeks thereafter. Specifically, as compared with immediately after the dyeing process, an increase in the numerical value of about 1 to 4 as the saturation value of the Munsell color system and a decrease in the numerical value of about 1 to 2 as the brightness value are observed. The hue value of the Munsell color system in the Munsell color system was in the range of 10B to 2.5PB, saturation 6 to 12, and brightness 7 to 5. Such a phenomenon could not be observed at all when using freshwater pearls as in Examples 2 to 5 described above.

  Further, in this example, oxidation was performed in a state where the pearl was allowed to stand without performing an operation of rotating the pearl during the oxidation treatment, but the entire surface of the pearl was uniform without causing uneven coloring in each pearl. It became dyed. For example, in the case of using freshwater pearls, compared to the fact that the unevenness of color on the surface of the pearls was high if the pearls were left standing without rotating them during the oxidation process. Thus, uniform dyeing even when allowed to stand in this way is very advantageous in obtaining a high-quality product. In this example, good colorability was observed even though the concentration of the dye solution used was relatively low.

  Also in this example, in the obtained colored pearls, there was substantially no change in the original luster, shine, etc. of the pearls used, so that the color of the well-colored pearls and the high-grade pearls Combined with the original high-quality luster and shine, the result was a very beautiful colored pearl.

  Furthermore, the cross section of the obtained colored pearl was observed using an optical microscope (digital microscope KH-8700, manufactured by Hilox Co., Ltd.), and the penetration degree of the dye (indigo) was examined. As a result, the dye penetrated over the entire pearl cross section, and strong dyeing was observed particularly in a region (pearl layer) having a depth of 500 μm or more from the surface.

Example 11
A natural indigo concentrate (manufactured by Tanaka Naoten Store Co., Ltd.) is used as the leuco body stock solution of indigo dye, and the dye solution is diluted with water so that the leuco body is contained at a rate of 111 g / L in terms of dry weight. About 200 ml was prepared. In addition, at the time of dilution, it adjusted so that liquid temperature might be in the range of 15-25 degreeC using warm water in part like Example 1. FIG. Furthermore, hydrosulfite was added to this diluted water at a rate of 5 g / L for deoxygenation treatment. The prepared dye solution was transferred to a commercially available flexible resin bag with a zipper, and mixed with care so as not to foam as much as possible so as not to touch air.

  On the other hand, 10 pearl oyster pearls each having a diameter of 3.0 to 3.5 mm, a diameter of 4.0 to 4.5 mm, and a diameter of 5.0 to 5.5 mm (one that has been subjected to a single hole opening treatment) are lightened. After washing with water and still wet, it was gently put into a flexible resin bag with a zipper containing the dye solution, and the air in the bag was discharged to the outside as much as possible and sealed. In this state, the mixture was allowed to stand at room temperature (20 ± 5 ° C.), and the pearl was immersed in the dye solution for 48 hours. After 48 hours of immersion, the pearls were removed and oxidized and dried in air for 8-9 hours while slowly rotating on a flat plate. After the first immersion and oxidation treatment, the pearl color did not change much.

  Next, this pearl is again put in a flexible resin bag with a zipper containing the same dye solution as described above, and left at room temperature (20 ± 5 ° C.) as described above, and immersed for 48 hours, After the treatment, the step of oxidizing and drying the pearls taken out in the same manner as described above in the air for 8 to 9 hours while slowly rotating on a flat plate was further repeated 4 times (total 5 times). A great change in the color of the pearls was observed by repeating this immersion and oxidation treatment five times. The colored pearls were finally washed with water and sufficiently dried naturally.

Although the colored pearls obtained after natural drying have some coloration differences depending on the individual, the hue values of the Munsell color system Munsell hue ring are 10B-5PB, saturation 4-10, brightness 5-8. It was within the range.
In general, the smaller the pearl diameter, the darker the color.

  Furthermore, the obtained colored pearl was put in a sealed polyethylene sachet and allowed to stand, and it was observed whether or not the color of the pearl was changed. As a result, the color of the colored pearl changed to a slightly deeper color in the period of about 7 days to 4 weeks thereafter, but the degree was slightly smaller than that in Example 10.

  Furthermore, the cross section of the obtained colored pearl was observed using an optical microscope (digital microscope KH-8700, manufactured by Hilox Co., Ltd.), and the penetration degree of the dye (indigo) was examined. As a result, the dye penetrated over the entire pearl cross section, and strong dyeing was observed particularly in a region (pearl layer) having a depth of 500 μm or more from the surface.

Examples 12-15
In Example 2, freshwater pearls were dyed under substantially the same conditions except that CIVat Blue 4, CI Vat Red 24, CIVat green 7, and CIVat Brown 1 were used instead of indigo dyes.
The obtained colored pearls have a slight degree of coloring depending on the individual, but in any of the dyes, the Munsell color system has a saturation of 5-12 and a brightness of 5-8. It was. In addition, the dye was dyed entirely in the pearl cross section, but was particularly strongly dyed in a depth region of at least about 500 μm from the surface.

Comparative Example 1
The dyeing treatment was performed in the same manner as in Example 1 except that the dye solution was prepared so as to contain the leuco body at a rate of 5 g / L in terms of dry weight.

  As a result, the obtained pearl is hardly colored, and the hue value of the Munsell color wheel of the Munsell color system is in the range of 10.0Y to 5.0GY, saturation 0 to 1, brightness> 9.0. there were. In this example, the number of repetitions of the dye soaking step and the oxidation step was sequentially increased from 3 times, and attempts were made to extend each soaking time and oxidation treatment time. No coloring was seen.

Claims (12)

A method for producing a colored pearl for coloring a pearl with a dye,
(A) Non-oxidizing to a dye solution containing a leuco body of at least one dye selected from the group consisting of a vat dye and a sulfur dye in an aqueous solvent at a rate of 5 to 400 g / L in terms of dry weight A step of immersing the pearl in a temperature condition of 0 to 60 ° C. for 1 hour or more in an atmosphere; and (b) taking the pearl out of the dye solution after a predetermined immersion time, and a temperature condition of 0 to 60 ° C. in an oxidizing atmosphere. The process of oxidation treatment for 1 hour or more,
The manufacturing method of the colored pearl characterized by repeating the said (a) process and (b) process in multiple times.   The method for producing a colored pearl according to claim 1, wherein the at least one dye selected from the group consisting of the vat dye and the sulfur dye is indigo.   3. The method for producing a colored pearl according to claim 2, wherein in the step (a), a dye solution containing an indigo leuco body in an aqueous solvent at a rate of 25 to 120 g / L in terms of dry weight is used. .   The method for producing a colored pearl according to any one of claims 1 to 3, wherein a pearl that has not been subjected to an opening treatment is used as a pearl colored with a dye.   The manufacturing method of the colored pearl of Claim 1 or 2 which uses the pearl by which the opening process was carried out as a pearl colored with dye.   The method for producing a colored pearl according to any one of claims 1 to 3, wherein fresh water pearls are used as the pearls colored with the dye, and the oxidation treatment in the step (b) is performed while rotating the pearls. .   Akoya pearls are used as the pearls colored with the dye, and after the above steps (a) and (b) are repeated a plurality of times, a stabilization step is further provided in which the pearls are allowed to stand for about 7 days to about 30 days. The manufacturing method of the colored pearl as described in any one of Claims 1-3. A pearl dyed with at least one dye selected from the group consisting of vat dyes and sulfur dyes, wherein the pearl surface has a chroma of 2.5 to 14 in the Munsell color system and a lightness of 1.5 to 9 in it, or a and lightness 8-9 chroma 1.0-2.0, also colored, wherein said dye is present in the depth region of up to at least 200μm from the surface of the pearl sectional smell Teso pearl. The dye is indigo, and the pearl surface has a Munsell hue ring (40 hues) with a hue value of 7.5BG to 10PB, a saturation of 2.5 to 14, and a lightness of 1.5 to 9. Alternatively, the colored pearl according to claim 8 , which has a hue value of 7.5BG to 10PB, a saturation of 1.0 to 2.0, and a lightness of 8 to 9.   The dye is indigo, and the pearl surface has a hue value of 10B to 5PB, a saturation of 2.5 to 14 and a lightness of 3 to 9 in the Munsell color system (40 hues) of the Munsell color system. 9. Colored pearls according to 9. The colored pearl according to claim 8, 9 or 10 , which is not subjected to an opening treatment. The colored pearl according to claim 8, 9 or 10 , which has been subjected to a hole opening treatment.