KR20010060437A - The Process for producing of Silk Fibroin Powder - Google Patents

Abstract

PURPOSE: A method for manufacturing silk fibroin powder is provided to simply and economically manufacture silk fibroin powder for using as a cosmetic material, a cosmetic additive and other industrial uses. CONSTITUTION: A silk raw material is degummed by treating the silk raw material with an aqueous solution containing a neutral detergent. The degummed silk raw material is heated to over 150deg.C and stirred in glycerol, ethylene glycol, or an aqueous solution thereof to make a suspension, and then cooled. Water or alcohol solvent like methanol, ethanol and isopropyl alcohol is added to the suspension and stirred. The stirred suspension is filtered and dried to produce silk fibroin powder. The dried silk fibroin powder is pulverized to get fine silk fibroin. The silk raw material is selected from among cocoons, raw silk, waste cocoons, raw silk waste, bisu(unreelable cocoons), silk fabric waste and bourette.

Description

Process for producing silk fibroin powder

The present invention relates to a method for obtaining silk fibroin powder from silk raw materials.

Silk fibroin powder has excellent properties such as proper hygroscopicity, excellent moisturizing property, skin affinity, soft touch to the skin, excellent oil and moisture balance, and moderate UV absorption ability. It is used.

The method for producing silk fibroin powder is (1) dissolving the degumming silk raw material in an aqueous solution of inorganic salt such as CaCl ₂ and then dialyzing to remove the inorganic salt and adding coagulation salt, blowing air or adjusting pH to the resulting fibroin solution. Or by exposing to ultrasonic waves or vigorously stirring to form a gel, followed by water removal and grinding to form silk fibroin powder (USP 4,233,212); And (2) a method of treating the raw material with an aqueous alkali solution to weaken the tensile strength of the silk and then grind it (USP 5,853,764). However, because the first method is a complex process such as degumming, dissolving into an inorganic salt solution, dialysis, gelling, dehydration, and pulverizing, a large amount of inorganic salt is required, and a dialysis process takes a long time. There is a disadvantage in that the production cost is high and productivity is low, and in order to obtain silk fibroin powder of fine particles by the second method, it has to be pulverized several times and has a disadvantage in that the yield is decreased due to the loss during alkali treatment. In addition, a method of precipitating silk fibroin by hydrolyzing the silk in an aqueous solution of acid or alkali and then neutralizing it or adding alcohol is used. The silk fibroin obtained in this way has a problem of completely losing the characteristics of silk as an oligomer having a small molecular weight. .

These conventional methods can be said to have a lot of room for improvement because the process is complicated and the productivity is low, the initial investment cost is relatively high and the production cost is high.

It is an object of the present invention to provide a process for producing silk fibroin powder from silk raw materials in high yield through a simple and economic process.

In order to obtain silk fibroin powder in a high yield from a silk raw material in a simple process, (1) the silk raw material is treated with an aqueous neutral detergent solution and degumming, and (2) the obtained degumming silk raw material is subjected to ethylene glycol, Silk fibroin powder produced by heating and stirring in glycerol or an aqueous solvent thereof at a temperature of 150 ° C. or higher and cooling (3) by adding water or alcohols such as methanol, ethanol, isopropyl alcohol, stirring, filtering and drying (4) to provide a method for obtaining fine fibroin of fine powder by grinding. Silk raw materials that can be used in the present invention may be used such as Cocoons, raw silk, waste cocoons, raw silk waste, bisu (unreelable cocoons), silk fabric waste, bourette, raw material which has been degumming or removed sericin by any known method before use Can be used.

Hereinafter, the present invention will be described in detail.

In the degumming process of the present invention, 30% of a 3% (w / v) neutral detergent solution is added to the silk raw material in a weight-to-volume ratio and heated at a temperature of 95 to 100 ° C. for 3 hours to wash the silk raw material with water to degumming. Silk raw material is obtained. 5 to 15 times the weight-to-volume ratio of ethylene glycol, glycerol or an aqueous solution thereof was added to the degumming silk raw material and stirred for 1 to 2 hours to obtain a suspension at a temperature of 150 to 180 ° C., and the resulting suspension was filtered as it is. After cooling to below the boiling point of the dried or added solvent, 0.5 to 3 times water or alcohols such as methanol, ethanol and isopropyl alcohol were added in a solvent volume ratio, and the resulting suspension was filtered and dried to obtain silk fibroin powder. . The obtained silk fibroin powder was pulverized to obtain fine silk fibroin powder.

Here, it is preferable to set the solvent such as ethylene glycol, glycerol or an aqueous solution thereof added to the degumming silk raw material as much as possible, but since the fibrous silk raw material is bulky and absorbs the solvent, the amount of solvent is 5 times by weight to volume ratio. To 15 times. In addition, solvents such as ethylene glycol, glycerol or an aqueous solution thereof are added to the degumming silk raw material, and the solvent added to the suspension obtained by heating and stirring is also not used or the amount of solvent is set as low as possible, but there are limitations in the filtration and washing process. Therefore, 0.5 to 3 times of an additional solvent was used in volume ratio. In this case, water or alcohols such as methanol, ethanol, and isopropyl alcohol are suitable as the additive solvent.

As described above, the method for producing silk fibroin according to the present invention is a method of high productivity because the silk fibroin powder can be produced by a simple process, unlike the conventional method for producing silk fibroin powder, so that the working time is reduced and the yield is high. Silk fibroin powder can be produced with minimal equipment, and there is no fear of mixing various inorganic salts.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are not intended to limit the invention only.

<< Example >>

<< Example 1 >>

150 ml of a 3% neutral detergent aqueous solution was added to 5 g of the silk raw material, heated at a temperature of 95 to 100 ° C. for 3 hours, filtered, washed with water until the neutral detergent was completely removed, and dried to obtain 4.8 g of a degumming silk raw material. 24 ml of glycerol was added to 4.8 g of the degumming raw material, and the mixture was heated and stirred at 165 to 175 ° C. for 1 hour under a nitrogen stream, cooled to room temperature, and then stirred for 5 minutes by adding 50 ml of water. The resulting suspension was filtered, washed with water and dried to obtain 4.7 g of silk fibroin powder having a particle size of 20 to 30 µm. The obtained silk fibroin powder was pulverized again to obtain a silk fibroin powder having a particle size of 5 to 10 µm.

<< Example 2 >>

15 ml of ethylene glycol is added to 3 g of the raw material obtained by degumming in the same manner as in Example 1, and the mixture is heated and stirred at 165 to 175 ° C. for 1 hour under nitrogen stream, cooled to room temperature, and then stirred for 5 minutes by adding 30 ml of water. . The resulting suspension was filtered, washed with water and dried to obtain 2.9 g of silk fibroin powder with a particle size of 20 to 30 µm. The obtained silk fibroin powder was pulverized again to obtain a silk fibroin powder having a particle size of 5 to 10 µm.

<< Example 3 >>

15 ml of ethylene glycol was added to 3 g of the raw material obtained by degumming in the same manner as in Example 1, and the mixture was heated and stirred at 165 to 175 ° C. for 1 hour under a nitrogen stream, cooled to room temperature, and stirred for 10 minutes by adding 30 ml of ethanol. The resulting suspension was filtered, washed with water and dried to obtain 2.9 g of silk fibroin powder with a particle size of 20 to 30 µm.

According to the present invention, silk fibroin powder which is useful not only for cosmetic additives or cosmetic raw materials but also for other industrial uses can be produced by a method having high economical efficiency and practicality.

Claims (5)

In producing silk fibroin powder from silk raw materials (A) Silk material is treated with an aqueous neutral detergent solution, filtered and washed to degumming (B) The obtained degumming raw material is obtained under glycerol, ethylene glycol or an aqueous solution thereof. Heat stirring to make a suspension (C) Cool below the boiling point of the solvent to add water or alcohol solvent After stirring to make a secondary suspension, it was filtered and dried to obtain silk fibroin powder. (D) Grinding the obtained silk fibroin powder to obtain a fine powder of silk fibroin Way The method of claim 1, wherein the solvent used in the step (b) is glycerol, ethylene glycol or a method of producing silk fibroin powder, characterized in that the boiling point of glycerol solution or ethylene glycol aqueous solution of 160 ℃ or more. The method for preparing silk fibroin powder according to claim 1, wherein the solvent added in the step (c) is water or alcohols having four or less carbon atoms such as methanol, ethanol, and isopropyl alcohol. The method for producing silk fibroin powder, characterized in that the particle size of the silk fibroin powder obtained in step (c) of claim 1 is 50 μm or less. The method for producing silk fibroin powder, characterized in that the particle size of the silk fibroin powder obtained in step (d) of claim 1 is 15 μm or less.