JP2002265498A - Method for isolating sericin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for collecting sericin with the need of neither energy cost nor long time for thawing after freezing, and to provide a method for efficiently extracting sericin from silk fibers enabling the sericin to be collected with slight molecular weight drop and low impurity content with the need of neither energy cost nor long time for thawing after freezing. SOLUTION: This method for isolating sericin from a mixed liquid of the sericin and water is characterized by comprising the following practice: in the mixed liquid, numerous fine bubbles generated by e.g. adding hydrogen peroxide solution to the mixed liquid are raised to form gel-like lumps of sericin followed by filtering the lumps to separate them from water and then drying the lumps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for separating sericin from a mixture of sericin and water to obtain sericin powder.

[0002]

2. Description of the Related Art In recent years, sericin has been added to foods and cosmetics for use. Sericin is extracted from silk fibers. As a method for extracting sericin from silk fibers, a silk fabric is boiled with a Marcel soap or an alkali solution as necessary. This method is used in a usual refining process of silk fabric, and sericin is recovered from a refining waste liquid generated in this process. In addition, sericin recovered by this method contains a large amount of impurities such as bleaching agents necessary for refining, including components of marcel soap and alkaline solution, and becomes a problem when used in the field of food and cosmetics. Purification treatment such as ultrafiltration is performed to remove impurities. The sericin-containing liquid thus obtained is dried by a freeze-drying method, a spray dryer method or the like to obtain a sericin powder. This method requires a lot of energy costs to dry a large amount of water.

On the other hand, as disclosed in JP-A-11-131318, silk fabric is treated with high-temperature and high-pressure water to extract sericin,
A technique has been disclosed in which this extract (mixture of sericin and water) is frozen and then thawed to gel sericin, and the gel separated from water by filtration is dried to obtain a sericin powder. This method dries the extract concentrated in a gel state, thereby saving energy cost for drying water. Further, since a chemical solution does not have to be used for the treatment, the obtained sericin has less impurities as compared with sericin recovered from the waste liquid in the ordinary refining process.
However, the high-temperature and high-pressure treatment significantly reduces the molecular weight of sericin. In addition, treatment with high-temperature and high-pressure water requires a large-scale apparatus such as a high-pressure kettle, and equipment costs are high. In addition, energy costs and long times are required to thaw after freezing.

[0004]

SUMMARY OF THE INVENTION The present invention solves these problems and aims to provide a method for recovering sericin which does not require long time and energy cost for freezing and thawing. It is another object of the present invention to provide a method for efficiently extracting sericin from silk fiber, which does not require energy cost and long time for thawing after freezing, and can be recovered in a state in which the molecular weight is reduced and the impurities are small.

[0005]

SUMMARY OF THE INVENTION The gist of the present invention is a method for separating sericin from a mixture of sericin and water, wherein the sericin is raised by raising a large number of fine bubbles in the mixture. The present invention provides a method for separating sericin, which comprises producing a lump of a gel-like substance, filtering the lump, separating the lump from water, and then drying.

The bubbles may be generated by adding hydrogen peroxide to the mixture. The hydrogen peroxide may be added in an amount of 0.03 to 10% by weight based on the mixture.
The bubbles may be generated by throwing an object that generates carbon dioxide gas into water when thrown into water.

[0007] The mixed liquid may be a lower pipe waste liquid.

The mixed solution is obtained by immersing an aggregate of silk fibers in water to swell sericin contained in the fibers, and then compressing the aggregate swelled with sericin by a press. Can be

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have studied a phenomenon in which a large number of microbubbles are raised toward a liquid surface in a mixed solution of sericin and water, thereby forming a gel-like mass of sericin. The present invention was completed based on this phenomenon. Separation of the lump from water followed by drying gives a sericin powder.

In order to extract sericin originally contained in a silk thread constituting a cocoon, the silk thread is first boiled or treated with hot water together with a chemical to obtain a mixed solution of sericin and water. Also, the sericin contained in the silk thread is swollen with water to give the silk thread a pressing or ironing action, whereby the sericin contained in the silk fiber is separated from the silk fiber to separate the sericin and the water. Can also be obtained. In the mixed solution of sericin and water thus obtained, sericin is dispersed or dissolved in water.

When fine bubbles are generated in the mixed solution, the sericin dispersed in the water gathers so as to be pushed up above the water, and a gel-like mass is formed on the water. The sericin in the mixed solution is not completely dissolved in water but seems to be dispersed in a fine gel form.However, air bubbles adhere to the fine gel sericin and the air bubbles rise, so It is thought that the fine gel-like sericin gathers so as to be pushed up above the water, and a gel-like mass is formed on top of the water. When sericin is completely dissolved in water, the formation of such a gel-like mass is not seen even if fine bubbles are generated, but the sericin molecules are associated by the stimulation of the fine bubbles to form a fine gel. If so, a gel-like mass is formed. If the mixture is cloudy from the beginning with a fine gel made of sericin, a gel-like mass is likely to be formed above water. When sericin dispersed in water has a large molecular weight, such turbidity occurs, and when fine bubbles are generated, a gel-like mass is likely to be formed above water.

The time required to generate fine bubbles in the mixture to form a gel-like mass on top of water is 0.5%.
About 3 to 3 hours, which is much shorter than the time required to freeze and thaw the mixture to gel the sericin, which is 7 to several tens of hours. This is a great advantage in industrially producing sericin powder.

[0013] The gel-like mass formed on the water in this manner is separated from the water by filtration, taken out and dried,
Obtain sericin powder. Drying can be performed by a conventional method such as freeze drying or spray drying.

As a method of generating fine bubbles in the mixture, fine bubbles generated by feeding gas into an existing mechanical fine bubble generator may be dispersed downward in the mixture. An object that generates a gas when charged into the mixture may be charged into the mixed liquid. For example, carbonated water in which carbon dioxide is dissolved under high pressure may be added to the mixture to generate fine bubbles of carbon dioxide in the mixture. A foaming agent may be charged into the mixture to generate fine bubbles. Hydrogen peroxide solution may be added to the mixture to generate fine oxygen bubbles. A method using carbonated water, a foaming agent, or hydrogen peroxide is preferable because it does not require a large-scale apparatus or power for generating fine bubbles, and is simple in operation, as compared with a method using a mechanical fine bubble generator. In the method using hydrogen peroxide, the mixture can be sterilized by the addition of hydrogen peroxide, so that the object can be stored for a long time after the addition. Therefore, in the case of industrial implementation, the work schedule can be planned and operated flexibly.

The amount of hydrogen peroxide to be added is preferably 0.03 to 10% by weight based on the mixed solution. If the amount of hydrogen peroxide is less than 0.03% by weight, the gel is not sufficiently separated, and if the amount exceeds 10% by weight, the separation effect does not change even if it is added more, and it is economically disadvantageous. Becomes

The filtration is performed by suction filtration using a filter paper or a filter cloth. As the filter cloth, a woven fabric or a nonwoven fabric is used.

The gel of sericin obtained by gelation and filtration by such a method has a higher concentration than the original sericin mixture, and requires less drying time and energy for powdering. I can do it.

In the present invention, it is preferable that the molecular weight of sericin in the mixed solution is large because gelation is further promoted. For example, it is desirable that the sericin be separated from the silk fiber without being chemically damaged. Specifically, sericin contained in and adhered to the silk fiber is separated from the silk fiber by applying a pressing or ironing action to the silk fiber by another object or by itself. As a result, sericin is separated from the silk fiber with little decrease in molecular weight and with little contamination of impurities.

In this case, it is preferable that the silk fiber or thread is given a pressing or ironing action in a wet state.
In addition, when applying a pressing or ironing action to the fiber or the yarn, it is more preferable that sericin swells with water or a chemical solution, since sericin is easily separated from the fiber. Such an embodiment can be realized by separating sericin from the yarn in the lower tube winding step. The lower tube winding process is a process of winding the lower tube in order to put it on an eight-chow twisting machine that twists the weft,
This is a step of winding a thread in which ten to several tens of silk fibers are wrapped around the lower tube with high tension in a state of being wetted with water. In the lower tube winding step, the ligated yarn is previously wound around a shackle, and the shackled yarn is immersed in hot water at 80 to 85 ° C. This immersion step is called a wetting step, in which sericin present in the fibers is swollen with water. The wrapped yarn that has undergone the weft boiling process is subjected to a lower tube winding process in a wet state. In the lower tube winding step, since the wound body is formed by winding the yarn with high tension, the yarn is compressed by the pressure generated inside the wound body, and the sericin attached to the fibroin of the silk fiber is formed. Is exfoliated and oozes out of the wound body together with water, and is collected as a lower pipe waste liquid.

The waste liquid generated in the lower pipe winding step (hereinafter referred to as lower pipe waste liquid) contains sericin separated from silk fibers. This sericin is partially dissolved in water, and most of it is swelled in water and dispersed in the lower tube waste liquid. This appearance is similar to the appearance of snow mixed with water that has not completely melted and is floating in the water in a semi-transparent state in a sherbet-like state. Refining waste liquid or silk fiber
In the treated water obtained by treating at a high temperature of 00 ° C. or more, sericin is dissolved in water, and such a translucent white turbid state is hardly observed. In such treated water, formation of a lump of gel-like material due to fine bubbles is hardly observed. For such treated water, it is preferable to promote the gelation by leaving the treated water for a long time, and then to form the mass of the gel-like material by the fine bubbles.

Further, since the lower tube waste liquid does not contain a chemical solution used in the refining of textiles, the lower tube waste liquid containing sericin thus obtained is freeze-dried as it is or powdered with a spray dryer. The resulting sericin does not contain impurities such as soaps, surfactants, refining agents such as alkaline agents, auxiliary agents, and bleaching agents used in refining.

Sericin obtained from lower tube wastewater is not subjected to the action of high-temperature and high-pressure water or a chemical that denatures or decomposes sericin or breaks molecular chains. It is close to existing sericin and has a smaller decrease in molecular weight than naturally occurring sericin. Such a lower tube waste liquid is easily gelled according to the present invention.

A photograph showing a state in which a hydrogen peroxide solution is added to the waste liquid to cause gelation is shown. FIG. 1 shows a state in which a 35% by weight aqueous solution of hydrogen peroxide was added so that the weight concentration of hydrogen peroxide became 1.75%, and the mixture was allowed to stand for 3 hours. (Indicated by arrow A in FIG. 1)
The bottom of the flask (indicated by arrow B in FIG. 1) becomes clear water.

FIG. 2 shows how gelation occurs when the weight concentration of hydrogen peroxide is different. A0 is not added, A1, A2,
A3 and A4 are 0.035, 0.07, and 0.5, respectively.
3, 1.75% by weight. The standing time after adding the hydrogen peroxide solution is 22 hours. The higher the weight concentration of hydrogen peroxide, the more clear water at the bottom of the container. In other words, the sericin concentration of the upper gel-like sericin aggregate is high. Also, as time elapses, the amount of clear water at the bottom of the container increases.

[0025] In another embodiment for applying a pressing or ironing action to silk fibers or yarns, an aggregate of silk fibers is immersed in water to swell sericin contained in the fibers, and then the aggregate is pressed. A method of compressing sericin by a press and squeezing sericin is effective. The aggregate of silk fibers may be made of waste thread, waste cocoon, and waste cotton. Further, as still another mode of giving a compressing action to the yarn, it is also effective to twist the yarn or the skein-shaped yarn. Prior to the compression or twisting, it is more preferable to wet the silk fiber or the lump of thread with a liquid such as water at room temperature to 100 ° C. for swelling sericin to swell the sericin attached to the fiber. . Alternatively, it is more preferable to treat the fiber or yarn mass with steam to swell the sericin attached to the fiber.

Before compressing or twisting, swelling the sericin adhering to the fiber by immersing the fiber or yarn in water at 40 ° C. or higher and lower than 100 ° C. promotes swelling and damages sericin. And it is more preferable because the trouble of removing residual chemicals can be omitted. 75-9 before compression or torsion
It is most preferable to swell the sericin adhering to the fiber by immersing it in water at 8 ° C. to further promote the swelling, not to damage the sericin, and to save the trouble of removing residual chemicals. . As a specific method of compression, it is effective to press using a press machine, squeeze the liquid by a squeezing roll composed of a pair of rolls, compress a lump of fibers or yarns by a centrifugal dehydrator, and squeeze the liquid. At the time of compression, a liquid such as water may be added to the fiber or yarn mass in advance to promote oozing of sericin.

It is also effective as a means for compression to press and nip a wet thread or lump of thread with a nip roll.

[Example] (Example 1) Twenty cocoons are wound around a wooden frame. The yarn wound on the wooden frame was immersed in water at 95 ° C. for 45 minutes while being wound on the wooden frame, and was lifted. Thereafter, it was wound around a lower bobbin.
Pressure generated by the tension of the adjacent yarn was generated in the yarn constituting the wound body, and sericin attached to the fiber was squeezed out together with water. The dropped mixture of sericin and water (lower tube waste liquid) was collected from each weight and collected. The recovered lower tube waste liquid was cloudy, and the sericin concentration was 0.7% by weight.

300 cc of the lower tube waste liquid was placed in a beaker containing 1 liter, and 1% of a hydrogen peroxide solution having a concentration of 35% by weight was added. By this addition, the gel-like sericin aggregated on the upper part of the lower tube waste liquid. This gel sericin was separated by suction filtration. Non-woven fabric (1.65 dte) as filter cloth
x Polyester / rayon use: thickness 0.33 mm, basis weight 35 g / m ² ), filtered over 30 minutes, and passed through water to obtain 150 g of gel-like sericin as a residue. The sericin concentration in the gel-form sericin was 1.2%, and the sericin concentration was higher than that in the lower tube waste liquid. The sericin in a gel state was dried to obtain 1.5 g of dried sericin. The recovery from sericin in the lower tube waste liquid was 71%.

Example 2 300 cc of lower tube waste liquid obtained in the same manner as in Example 1 was placed in a beaker containing 1 liter, and 20 ml of commercially available carbonated water was added. By this addition, the gel-like sericin aggregated on the upper part of the lower tube waste liquid. This gel sericin was separated by suction filtration. The same nonwoven fabric as that used in Example 1 was used as the filter cloth, and filtered over 30 minutes, and water was passed through to obtain 120 g of gel-like sericin as a residue. The sericin concentration in the gel sericin was 1.0%, and the sericin concentration was higher than that in the lower tube waste liquid. The gel-form sericin was dried to obtain 1.6 g of dried sericin. The recovery from sericin in the lower tube waste liquid was 76%.

[0031]

According to the method for extracting sericin of the present invention, sericin can be efficiently recovered without taking much time and without requiring large-scale additional equipment.

[Brief description of the drawings]

FIG. 1 is a photograph showing a state in which a hydrogen peroxide solution is added to a lower pipe waste liquid to cause gelation.

FIG. 2 is a photograph showing a state of gelation of a lower tube waste liquid when the weight concentration of hydrogen peroxide is different.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hajime Miyake 27-39, Mitsuyamotocho, Nagahama-shi, Shiga Prefecture Inside the Northern Industrial Technology Center East, Shiga Prefecture (72) Inventor Hiroyuki Wakisaka 27-39, Mitsuyamotomachi, Nagahama-shi, Shiga Prefecture Higashi, Shiga Prefecture F-term in the Northern Industrial Technology Center (reference) 4H045 AA20 CA51 GA10

Claims (6)

[Claims] 1. A method for separating sericin from a mixture of sericin and water, wherein a large number of microbubbles are raised in the mixture to form a gel-like mass of sericin, and the mass is formed. A method for separating sericin, comprising filtering, separating from water, and drying. 2. The method for separating sericin according to claim 1, wherein the bubbles are generated by adding hydrogen peroxide to the mixture. 3. The method according to claim 1, wherein said hydrogen peroxide is added to said mixed solution in an amount of 0.1%.
3. The method for separating sericin according to claim 2, wherein the addition is performed in an amount of 03 to 10% by weight. 4. The method for separating sericin according to claim 1, wherein the bubbles are generated by throwing an object that generates carbon dioxide gas into water when thrown into water. 5. The method for separating sericin according to claim 1, wherein the mixed liquid is a lower pipe waste liquid. 6. The mixed liquid is obtained by immersing an aggregate of silk fibers in water to swell sericin contained in the fiber, and then compressing the aggregate swelled with sericin by a press. 5. The method according to claim 1, wherein
The method for extracting sericin according to any one of the above.