KR101667382B1 - Homogeneously and partially degummed silk and preparation method thereof - Google Patents

Abstract

More particularly, the present invention relates to uniformly refined silks, and more particularly, to refining silks by performing the refining process in an optimal range to uniformly refine the silks to obtain a soft touch of a degummed silk, The present invention provides silk fibers and fabrics of new characteristics that are uniformly refined so as to have a new feel and luster with a medium feel between a refreshing feeling of stiffness and to ensure excellent leveling properties.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partially refined silk,

The present invention relates to a uniformly refined silk, and more particularly to a method of uniformly refining a silk, comprising performing the refining process of the silk in an optimized range.

Silk has been widely used as the best garment material for thousands of years based on its excellent strength, luster, texture and texture. Silk is a composite of two different polymeric materials, fibroin and sericin, and sericin is surrounded by two strands of fibroin. When using silk as a garment material, sericin has mainly been removed. The process of removing sericin from silk is called degumming. When the sericin is removed through refining, two strands of fibroin appear, and the diameter of the fiber is reduced to less than half of that before the sericin removal. Therefore, Because of its layered structure, it has been refined in many cases for silk because of its excellent glossiness, and sericin was recognized as a target to be removed through refining. On the other hand, if the disadvantage of removing sericin through refining is to remove sericin, which accounts for more than 25% of the price of silk, which is a high-priced fiber, the cost of silk increases further and there is a considerable cost to eliminate sericin And it is generated as a refining waste liquid, and there is a disadvantage that environmental treatment costs are additionally generated.

However, in recent years, a variety of textile materials having various characteristics have been desired in the clothing industry. Therefore, in such an atmosphere, sericin is often used as a natural silk form (silk, silk, silk) obtained from cocoon rather than removing sericin . In other words, the original natural silk without removing sericin has a refreshing feeling unique to sericin, so it can be used as a sleeping material that can be worn coolly in summer. In this case, there is an advantage in that the sacrificial removal effect of silk weight loss can be prevented, and the addition cost and environmental treatment cost can be reduced by refining.

In this way, refined silk fabrics and refined silk fabrics are widely used as clothing materials for different characteristics and feelings through refining. However, in the market for clothing materials, It is demanding the development of silk fabrics.

The silk scouring fabric has excellent gloss and softness on the touch surface while the silk screed gives a feeling of stiffness and coolness. In the clothing material market, we are looking forward to the emergence of a new characteristic silk-part scouring fabric with these intermediate feel and luster. However, in practice, it is very difficult to partially refine the silk to obtain a new characteristic silk material having intermediate characteristics between the refining fabric and the green fabric. It is not difficult to partially remove sericin from silk flesh and green fabrics by different refining conditions such as refining agent, refining temperature, refining time, etc. However, the problem is that since silk has irregular nature as a natural material, It is very difficult to obtain. That is, the removal of total sericin amount from raw silk such as silkworm silk, silk silk and silk raw silk is easy, but the most difficult problem is that it is difficult to uniformly remove sericin. Therefore, sericin is removed in some areas and removed in some areas, resulting in irregular partial scouring. In particular, the silk yarn and silk fabrics tend to be more rough than crude silk because of the characteristic of sericin, which swells once in the area where less sericin is removed and hardens when dried. Therefore, according to the conventional method, the partially refined silk fabric can not obtain a touch between the degummed silk and the raw silk in the actual tactile sense. In addition, since sericin has a different degree of dye adsorption with fibroin, when uneven scouring is performed, the silk after the dyeing gives a very rough feeling and can not be used as a material for clothing.

Therefore, it is possible to provide an intermediate feeling touch and gloss between the soft feel of the degummed silk and the stiff feel of the raw silk, and a new characteristic of uniformly refined It is necessary to study the development of silk part refining fabric material and effective process development for manufacturing it.

The present invention seeks to provide a uniformly refined silk and a method for producing the same.

The present invention provides a silk fiber having an annual rate of 8% to 20% and a scintillation non-uniformity index of 10% or less as expressed by the following equation (1).

 [Equation 1]

[Equation 2]

Refining unevenness index (%) = (standard deviation of crystallization index / average of crystallization index) X 100

In the above formula (1), W ₁ is the dry weight (g) of the silk before refining, and W ₂ is the dry weight (g) of the silk after refining.

The present invention also provides a method for producing a silk fiber comprising the step of refining a silk using a refining solution comprising 0.2 to 20 parts by weight of an anionic surfactant per 100 parts by weight of the silk component.

The present invention also provides a silk fabric comprising the silk fibers.

Hereinafter, a uniformly refined silk according to a specific embodiment of the present invention, a method for producing the same, and a partially refined silk fabric including the refined silk fabric will be described in detail. It is to be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

In addition, throughout this specification, "comprising" or "containing ", unless specifically stated, refers to including any and all components (or components) Can not be interpreted as excluding.

The inventors of the present invention have found that sericin is uniformly removed to an optimum range by performing an optimized refining process as described below in the course of research on manufacturing uniformly refined silk, To obtain a novel partially scouring silk fiber. The present invention has been completed based on this finding.

According to one embodiment of the invention, uniformly refined silk fibers are provided. The silk fiber of the present invention has an annual rate of 8% to 20% and a scintillation non-uniformity index of 10% or less as represented by the following equation (1).

[Equation 1]

[Equation 2]

Refining unevenness index (%) = (standard deviation of crystallization index / average of crystallization index) X 100

In the above formula (1), W ₁ is the dry weight (g) of the silk before refining, and W ₂ is the dry weight (g) of the silk after refining.

Particularly, the present invention optimizes the refining solution composition and degumming process conditions to optimize the fiber elongation rate and refining non-uniformity index to a predetermined range, as described later, to obtain a degummed silk, the present invention provides uniformly refined silk fibers so as to ensure excellent leveling property with a new touch and gloss mid-level between the soft touch and the stiffness refreshing feeling between the raw silk.

The annual rate of silk fibers according to the present invention should be between 8% and 20%, preferably between 10% and 18%. The annual rate of the silk fibers is such that products having completely different properties from those of the completely refined silk fibers (that is, all of the sericin are removed) and the silk yarns and silk fabrics produced therefrom can be obtained, and at the same time, In order to be able to obtain more than 8%. In addition, the annual rate of the silk fibers of the present invention makes it possible to obtain products which are completely different from the raw silk yarns and raw fabrics and at the same time, 20% or less in terms of ensuring uniformity and excellent tactile feel .

In the silk fibers of the present invention, the refining non-uniformity index may be a percentage of a value obtained by dividing the standard deviation of the crystallization index by the average of the crystallization index, as shown in the following equation (2).

[Equation 2]

Refining unevenness index (%) = (standard deviation of crystallization index / average of crystallization index) X 100

In the above formula 2, the crystallinity index is represented by the following formula 3.

[Equation 3]

X 100Crystallinity Index (%) =

X 100

In the formula 3, A _1235cm ^-1 is the absorbance in the infrared spectroscopic analysis when 1,235 cm ^-1, A _1260cm ^-1 is the absorbance at 1,260 cm ^-1.

The refining non-uniformity index of the silk fibers according to the present invention may be 10% or less, or 0.1% to 10%, preferably 9.5% or less. The scintillation non-uniformity index means the degree of uniformity of sericin remaining in the same silk sample or the degree to which sericin has been uniformly removed. The scintillation uniformity index can be expressed in terms of uniform tactile property and uniformity 10% or less.

Also, the breaking strength of the fiber according to the present invention may be 8,000 KPa or more, and the breaking elongation of the fiber may be 3.0% or more.

On the other hand, according to another embodiment of the invention, a method for producing partially refined silk fibers as described above is provided. The method for producing the silk fiber may include a step of performing a refining process of the silk using a refining solution containing 0.2 to 20 parts by weight of an anionic surfactant per 100 parts by weight of the silk component.

The inventors of the present invention have found that in the course of research on manufacturing uniformly refined silk, it has been found that the use of water and anionic surfactant, without using a conventional scouring agent such as soap, sodium carbonate, citric acid or urea, And thus the present invention has been completed.

In general, a scouring agent means a substance having the property of dissolving sericin in water and promoting dissolution and decomposition to remove sericin from silk. In the case of known scouring agents, scouring, that is, removal of sericin occurs irregularly even when partial scouring is performed by controlling the amount of scouring agent, that is, in some places, excess serine is removed, The feeling of touch is deteriorated and the uniformity is deteriorated. However, in this refining process, since a uniform partial refining can be performed by using a specific surfactant in an optimum range in a refining process, a new excellent tactile feeling different from the softness of the existing refined silk raw fabric and the softness of the full refining silk Silk fabric of the present invention can be made, and the leveling property is also greatly improved.

In the uniform refining method according to the present invention, the surfactant may be used in an amount of 0.2 part by weight to 20 parts by weight, preferably 1 part by weight to 15 parts by weight, based on 100 parts by weight of the silk component. If the content of the surfactant is less than 0.2 parts by weight, the amount of the surfactant is insufficient and the silk portion refined product which is not sufficiently uniform is obtained. If the content of the surfactant exceeds 20 parts by weight, the surfactant does not completely dissolve, Too much bubbles are formed and the refinement is difficult or the cost of the surfactant is increased and the commerciality is greatly deteriorated.

Generally, silk is a typical natural fiber material obtained from silkworms, silkworms obtained by sacrificing silkworms, silkworms (silk yarn), silk fabrics obtained by woven silkworms, and the like. These natural silks are made up of a mixture of two different polymers that surround two silk fibroin layers. The natural silk, that is, the silk before refining, is comprised of about 65% to 80% by weight of fibroin in the total weight of the silk depending on the kind of the silkworm, and the sericin is 20% to 35% by weight.

Removal of sericin from these natural silks is called degumming, and refining of silk is possible in a variety of ways. Particularly, in the process for producing a uniform partial scouring silk according to the present invention, a surfactant aqueous solution is first prepared by dissolving a surfactant in water. Adding silk to the surfactant aqueous solution and treating the silk, removing the silk from the surfactant aqueous solution, washing it with water, and drying the silk.

Industrial Applicability According to the present invention, it is possible to provide a new feeling and gloss with a medium feel between a soft touch of a degummed silk and a refreshing feel of a stiff feel of a raw silk, A refining process is carried out using one or more anionic surfactants in order to impart partially refined properties. In particular, the anionic surfactant avoids the excessive sericin removal effect of the known scouring agent, but is more polar than the nonionic surfactant, so that the silk yarn is easier to approach and penetrate, Water and surfactant can easily penetrate to remove sericin. Therefore, the problem of non-uniform refining which occurs due to the fact that water and surfactant penetrate and refine, that is, sericin is removed and the other one is not refined because water and surfactant can not penetrate can be effectively solved. Examples of the anionic surfactant include sulfates and sulfonates. Examples of the anionic surfactants include organo phosphorescent surfactants, sarcosides, alkyl amino acids, and the like. There are a variety of surfactants.

In the refining process, the surfactant aqueous solution, which is a silk and a degumming bath, has a bathing rate of at least 1:10 w / v (g / mL) or 1: 10-1: 1000 w / v (g / ratio can be used. If the bath ratio is less than 1: 10 w / v (g / mL), the polishing liquid may not be sufficiently immersed in the silk, so sericin removal may not be effectively performed and the polishing process itself becomes very uneven. However, if the bath ratio exceeds 1: 1000 w / v (g / mL), the amount of water required for polishing may be excessively consumed, which may undesirably increase the manufacturing cost unnecessarily. In view of more effective refining process and reduction of process cost, the bath ratio of the silk to the surfactant aqueous solution is preferably 1:20 w / v (g / mL) to 1: 300 w / v (g / mL) . ≪ / RTI >

The refining process may be performed at a temperature of 60 to 150 ° C, preferably 80 to 110 ° C. At this time, the refining time may be 5 minutes to 6 hours, preferably 10 minutes to 3 hours. If the temperature of the refining step is less than 60 캜, the refining may not be sufficiently performed or the refining time may be greatly increased, which may increase the process cost. If the temperature of the refining step exceeds 150 ° C, the molecular chains of the silk may be cut off during the refining process, or the silk may be injured.

On the other hand, according to another embodiment of the invention, there is provided a silk fabric comprising partially refined silk fibers produced through the process as described above. Particularly, the partial scouring fabric of the present invention is characterized by exhibiting excellent leveling index and tactile feeling by using silk fibers having an annual rate and scintillation nonuniformity index within a predetermined range through an optimized scouring process as described above.

The silk fabric of the present invention may comprise an evenly refined silk fiber as described above, so that the annual rate can be 8% to 20%, preferably 10% to 18%. Also, the refining non-uniformity index of the silk fabric may be 10% or less, or 0.1% to 10%, preferably 9.5% or less. If the scouring non-uniformity index of the partial scouring fabric exceeds 10%, the remaining deviation of the sericin in the silk is large, so that fine stains appear when the stain is dyed, and rough and uneven stain is given to the silk stain. There is a problem that is difficult to use. Here, the annual rate and refining non-uniformity index of the silk fabric can be measured in the same manner as in the case of the silk fiber.

On the other hand, the silk fabric of the present invention may have a leveling index of not more than 25% or not more than 0.1% to 25%, preferably not more than 20%, expressed by the following formula 4.

[Equation 4]

The homogeneity index (%) = D / A × 100

In the above equation (4), D is the standard deviation of the K / S value measured using the Kubelka-Munk equation, and A is the standard deviation of the K / S value measured using the Kubelka-Munk equation It is the average of the K / S values.

The Kubelka-Munk equation is given by the following equation (5).

[Equation 5]

K / S = (1-R) ² / 2R

In the above equation (5), K is the absorption coefficient of the dye, S is the scattering coefficient of the dye, and R is the reflectance of the dye.

If the uniformity index of the partially refined silk fabric exceeds 25%, the product value is lowered as a material for clothing due to uneven dyeing, which makes it difficult to use.

In the present invention, matters other than those described above can be added or subtracted as required, and therefore, the present invention is not particularly limited thereto.

According to the present invention, when the partially refined silk is produced by optimizing the refining process for the silk, it is possible to uniformly obtain sericin partially removed in a predetermined range, and at the same time, Can be obtained.

1 is an electron micrograph (magnification of 1,000 times magnification) of partially refined silk yarn after refining silk yarn according to Comparative Example 1 of the present invention.
2 is a photograph of a general digital camera for partially refined fabrics after refining silk yarn according to Comparative Example 1 of the present invention.
3 is an electron micrograph (magnification of 1,000 times magnification) of partially refined silk yarn after refining silk yarn according to Example 1 of the present invention.
4 is a photograph of a general digital camera of a partially refined fabric after refining silk yarn according to Example 1 of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the following examples.

Examples 1-5

A raw silk yarn was used as a silk component. First, silk greening was refined at a boiling temperature (100 DEG C) for 1 hour using a surfactant aqueous solution having a bath ratio of 1: 100, followed by washing with distilled water to obtain partially refined silk greening.

At this time, the composition and refining conditions of the refining solution were performed as shown in Table 1 below. As the surfactant, sodium dodecylbenzene sulfonate, sodium sulfonic acid sodium salt and sodium dodecyl sulfate were used as the anionic surfactants, respectively.

The partially refined silk fabric thus produced was partially refined using a loom. The silk yarn wound on the bobbin was immersed in cold water and stored for 10 hours or more in a locked state, and then woven using a loom. The obtained fabric was dyed by natural staining method. The silk fabric was treated at 60 ° C for 20 minutes with a liquor solution in which the onion skin was boiled at 100 ° C for one hour or less, and dyed. After completion of dyeing, washing with water was repeated twice for 15 minutes to 20 minutes using cold water.

Comparative Example 1

As shown in the following Table 1, except that a refining process was carried out at 100 占 폚 for one hour without using a separate scouring agent, the partially refined silk yarn and the partially refined silk fabric .

Comparative Examples 2 to 5

As shown in the following Table 1, the partially refined silk yarn and the partially refined silk fabric using the same method as in Example 1 were produced, except that the refining process was carried out by varying the kind of the surfactant and the content of the surfactant Respectively.

The refining solution composition and refining process conditions for producing partially refined silk yarn according to Examples 1 to 5 and Comparative Examples 1 to 5 are as shown in Table 1 below.

division Type of surfactant Silk basis
Surfactant content
(owf, parts by weight) Bath Refining
Temperature
(° C) Refining
time
(minute) Example 1 sodium dodecylbenzene sulfonate 9 1: 200 100 60 Example 2 sodium dodecylbenzene sulfonate 3 1: 200 100 60 Example 3 sodium dodecylbenzene sulfonate One 1: 200 100 60 Example 4 lignosulfonic acid sodium salt 9 1: 200 100 60 Example 5 sodium dodecyl sulfate 9 1: 200 100 60 Comparative Example 1 - - 1: 200 100 60 Comparative Example 2 sodium dodecylbenzene sulfonate 0.1 1: 200 100 60 Comparative Example 3 polyethylene glycol hexadecyl ether 9 1: 200 100 60 Comparative Example 4 polyoxyethylene sorbitan monooleate 9 1: 200 100 60 Comparative Example 5 2,4,7,9-Tetramethyl-5-decyne-4,7-diol 9 1: 200 100 60

The partially refined silk yarn produced according to Examples 1 to 5 and Comparative Examples 1 to 5 and the partially refined silk fabric using the same were subjected to physical property evaluation in the following manner, As shown.

a) annual rate

First, the following equation 1 was used to measure the annual rate of partially refined silk fibers.

[Equation 1]

In the above formula (1), W ₁ is the dry weight (g) of the silk before refining, and W ₂ is the dry weight (g) of the silk after refining. Dry weights were measured using a moisture meter (XM60, Precisa, Switzerland).

b) refining non-uniformity index

In order to measure the refinement uniformity of the partially refined green yarn, the following equation 2 was used.

[Equation 2]

Refining unevenness index (%) = (standard deviation of crystallization index / average of crystallization index) X 100

An infrared spectrometer (Nicolet 380, Thermo Fisher Scientific, USA) and an attenuated total reflection (ATR) apparatus were used to measure the crystallinity index in the equation (2). The infrared spectroscopic spectrum was obtained by using an infrared spectroscopic analyzer, and the crystallinity index was measured therefrom using the following equation 3.

[Equation 3]

X 100Crystallinity Index (%) =

X 100

In the formula 3, A _1235cm ^-1 is the absorbance in the infrared spectroscopic analysis when 1,235 cm ^-1, A _1260cm ^-1 is the absorbance at 1,260 cm ^-1. The crystallinity index of silk is closely related to the content of sericin. Since the fibroin is mainly crystallized and the sericin is amorphous, the crystallinity index increases as the sericin content decreases Therefore, the crystallinity index obtained by infrared spectroscopy can be used as a measure of the degree of sericin residue.

c) leveling index

The dyed silk fabrics were divided into 9 equal sections (3 sections in width x 3 sections in 3 sections) in the same area and the reflectance was measured at intervals of 10 nm in the wavelength range of 360 to 740 nm with respect to each section. The K / S value was calculated using the Kubelka-Munk formula, and the total K / S summed over the wavelength range of the measurement range was expressed by the bath ratio, and the results were used to determine the level of uniformity. The equipment used to measure the reflectance was a Konica-Minolta Spectrophotometer CM-3600d, Japan, and was measured at 10 ° field of view on a D65 light source. In order to investigate the uniformity of polyester fibers, we analyzed the correlation between the fabric properties and the homogeneity of the polyester fibers in the dyeing process of polyester fibers (Jung, JG, Kim, TW, , 59 ~ 66, 2009) were measured using the equation (4) used for the homogeneity measurement.

[Equation 4]

The homogeneity index (%) = D / A × 100

In the above equation 4,

D is the standard deviation of the K / S value measured using the Kubelka-Munk equation,

A is the average of the K / S values measured using the Kubelka-Munk equation.

The Kubelka-Munk equation is given by the following equation (5).

[Equation 5]

K / S = (1-R) ² / 2R

In the above equation 5,

K is the absorption coefficient of the dye

S is the scattering coefficient of the dye

R is the reflectance of the dye.

d) Tactile evaluation of fabrics

A total of 10 researchers conducted a sensory evaluation on the texture of fabrics and rated them according to the following criteria.

+: Very bad

++: Poor

+++: Normal

++++: Good

+++++: Very good

division Annual rate
(%) Crystallinity index
(%) Refining Unevenness Index (%) Homogeneity index
(%) touch Example 1 18.0 23.4 4.9 5 +++++ Example 2 17.8 23.1 6.3 7 +++++ Example 3 17.6 23.0 8.7 9 +++++ Example 4 15.6 19.4 8.7 9 +++++ Example 5 15.6 16.8 9.1 10 +++++ Comparative Example 1 13.4 17.8 12.2 43 +++ Comparative Example 2 16.8 22.8 11.8 38 +++ Comparative Example 3 10.4 19.4 11.4 31 +++ Comparative Example 4 11.2 14.6 10.8 29 +++ Comparative Example 5 10.4 15.6 22.2 71 ++

As shown in Table 2, the silk fibers of Examples 1 to 5, in which the age and refining non-uniformity indexes were optimized according to the present invention, were uniformly refined so that the soft touch of the degummed silk and the softness of the raw silk it can be understood that excellent durability can be ensured at the same time while exhibiting an intermediate feeling of touch and gloss between the feeling of cool feeling of stiffness possessed by the silk. On the other hand, it can be seen that the silk fibers of Comparative Examples 1 to 5 produced according to the conventional method are not uniformly refined and the uniformity is remarkably lowered.

Particularly, in Examples 1 to 3 using sodium dodecylbenzene sulfonate as an anionic surfactant, when the silk-based surfactant content is 1% to 9% owf, the refining non-uniformity index is 9% or less And evenness index of less than 10% and very good tactile sensation showed that uniform partial scouring was possible by using anionic surfactant. Also, in Examples 4 and 5 using 9% of sodium sulfonic acid sodium salt and sodium dodecyl sulfate as other anionic surfactants, the refining non-uniformity index and the uniformity index were Low, and very good touch. As described above, when an anionic surfactant was used in an amount exceeding a specific amount, it was possible to uniformly refine, uniformly dye, and obtain a good feel of the obtained fabric.

On the other hand, in the case of Comparative Example 1 in which silk yarn was refined with hot water without using a surfactant, it was confirmed that the refining non-uniformity index and the uniformity index were high, resulting in irregular refining. As a result, Normal. In the case of Comparative Example 2 in which the content of the surfactant dropped to 0.1%, the scintillation non-uniformity index increased to 11.8%, the leveling index increased to 38% But did not show the effect of partial refining.

On the other hand, in the case of Comparative Examples 3 to 4 in which polyethylene glycol hexadecyl ether, which is a nonionic surfactant, and polyoxyethylene sorbitan monooleate, which are not anionic surfactants, were used, The index and homogeneity index increased slightly when the surfactant was not used. However, the degree of scintillation uniformity was not different from that of the surfactant, and the sensory scores were not significantly different from those before using the surfactant. However, the nonionic surfactant 2,4,7,9-tetramethyl-5-decyne-4,7-diol (2,4,7,9-Tetramethyl-5-decyne- In Comparative Example 5, the refining non-uniformity index and the homogeneity index rose to 22.2% and 71%, respectively, and the sensation was deteriorated, indicating that the surfactant was refined more uniformly than before using the surfactant.

On the other hand, the degree of unevenness of the scouring was observed in the results of visual observation and scanning electron microscopy. In the case of Comparative Example 1, as shown in Fig. 1, it was found that the removal of sericin was very rough and uneven In the result of the visual observation of the manufactured fabric (Fig. 2), streak-like patterns appeared and were nonuniform at both micro and macro levels. On the other hand, in the case of Example 1, as shown in FIG. 3, the results of the electron microscopy analysis (FIG. 3) showed uniform sericin removal, and even visually observed (FIG. 4) showed a uniform fabric state.

As a result, it was found that the anionic surfactant was effective to obtain uniform partial refining silk rather than nonionic surfactant as a result of the refining process in various ways for the uniform partial refining of silk. This makes it easier to approach and penetrate the silk yarn since the anionic surfactant is more polar than the nonionic surfactant, so that the water and the surfactant easily permeate uniformly throughout the silk and sericin is removed, It is believed that one side solves the problem of non-uniform refining which occurs due to the infiltration of water and surfactant into the refinement (that is, the sericin is removed) and the other does not refill because the water and the surfactant can not permeate.

Claims (8)

A silk fiber having an annual rate of 8% to 20% and a refining non-uniformity index of 10% or less represented by the following equation (1)
[Equation 1]

[Equation 2]
Refining unevenness index (%) = (standard deviation of crystallization index / average of crystallization index) X 100
In the above formula (1), W ₁ is the dry weight (g) of the silk before refining, W ₂ is the dry weight (g) of the silk after refining,
In the above formula 2, the crystallinity index is expressed by the following formula 3,
[Equation 3]
Crystallinity Index (%) =

X 100
In the formula 3, A _1235cm ^-1 is the absorbance in the infrared spectroscopic analysis when 1,235 cm ^-1, A _1260cm ^-1 Im is the absorbance at 1,260 cm ^-1. delete delete delete delete delete A silk fabric comprising the silk fiber according to any one of claims 1 to 4 and having an evenness index of not more than 25%
[Equation 4]
The homogeneity index (%) = D / A × 100
In the above equation 4,
D is the standard deviation of the K / S value measured using the Kubelka-Munk equation,
A is the average of the K / S values measured using the Kubelka-Munk equation.
delete

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