A silk sericin preservation process and high-sericin silk

Abstract

The present invention provides a silk sericin retention process and high-sericin silk, which relates to the field of mulberry silk processing technology, especially the field of mulberry silk processing technology. A silk sericin retention process is to immerse the raw silk white blank in a treatment solution to fully fix the sericin, and then successively perform water washing, degumming and rinsing to obtain high-sericin silk; the treatment solution includes 1-5 wt% of waterborne acrylic resin, 0.5-3 wt% of guanidine salt and 5-10 wt% of silane-modified polyurethane and the balance of water; through the chemical cross-linking method, the cross-linking agent fully penetrates into the interior of the raw silk white blank, and then under specific conditions, the acrylic resin and the silane-modified polyurethane fully react with the sericin to form a molecular entanglement structure, changing the chemical structure and properties of the sericin, thereby realizing the fixation of the sericin, reducing its water solubility, improving the anti-boiling and alkali resistance, and at the same time enhancing the hand feeling of the raw silk white blank product.

Description

Technical Field

[0001] The present invention relates to the field of mulberry silk processing technology, and particularly to a silk sericin preservation process and high-sericin silk. Background Art

[0002] Silk mainly consists of two parts: fibroin and sericin. Sericin coats the periphery of fibroin, accounting for about 20 - 30% of the silk quality. Sericin and fibroin are composed of 18 kinds of amino acids and contain about 97% pure protein. The fibers obtained through silk finishing processes belong to a kind of high-grade fabric raw material, and the chemical and physical properties of its fiber materials directly affect the comfort, feel, and dyeing uniformity of the fabric. Therefore, the functional treatment and finishing of silk fibers have always been a key area of concern in the silk industry.

[0003] The sericin layer in silk is prone to protein fiber swelling, rupture, and hydrolysis in weak acid and weak base aqueous solutions, and there is also the problem of hardening and caking after silk swells in water and dries. In traditional silk weaving and dyeing and finishing processes, sericin usually needs to be removed, and only the soft and elastic fibroin part is utilized, resulting in waste of sericin resources and environmental pollution. Therefore, it is of great significance to fix sericin on the surface of fibroin for retention.

[0004] In recent years, the research, promotion, and application of sericin fixation technology have, to a certain extent, not only solved this problem but also endowed silk with functional characteristics such as plumpness, thickness, and stiffness. Currently, the main types of sericin fixation agents studied at home and abroad include chromium salts, small molecule aldehydes, tannic acid, synthetic resins, active chlorine-containing s-triazine compounds, epoxy compounds, etc. There are a variety of them, but their performances are different, and they all have advantages and disadvantages to a certain extent.

[0005] The chromium salt has excellent sericin fixation effect, but it has its own color, and trivalent chromium salts are easily oxidized into carcinogenic hexavalent chromium salts under high temperature and high pH conditions, and it is hardly used for sericin fixation treatment.

[0006] Formaldehyde is a traditional method in the initial stage of sericin fixation development, with good effect. However, formaldehyde substances are extremely volatile, carcinogenic, and not conducive to human health. With the requirements for ecological and environmental-friendly silk fabrics, formaldehyde has gradually withdrawn from the sericin fixation application process. Although glutaraldehyde has a good sericin fixation effect (good cross-linking effect with proteins), it is prone to yellowing, which is not conducive to the processing of white and light-colored silk, and can only be used for the sericin fixation treatment of dark-colored silk products, greatly limiting the application range of glutaraldehyde sericin fixation.

[0007] Tannic acid lacks a certain amount of strong covalent bonding methods for chemical cross-linking of silk proteins, its cross-linking and sericin fixation effect is weak, and it has a relatively deep color itself. Using it to finish silk will dye the silk with a heavy color, having a greater impact on the dyeing performance of silk. This method is hardly used.

[0008] Zhou Hongxiang et al. reported the use of three epoxides for the fixation finishing of silk sericin. However, during the process of using these three compounds for silk finishing, a catalyst KSCN (a toxic substance) needs to be added, and these three substances must be used for fixing the glue in an organic solvent such as isopropanol. After treatment, a solvent such as acetone is also needed to wash away the unreacted epoxides on the silk. This method is limited to laboratory theoretical research.

[0009] In the above-mentioned treatment process, although the sericin is fixed, its alkali resistance is only improved to a limited extent and does not meet the formaldehyde content standard requirements; although the low-temperature reeling and low-temperature dyeing and finishing processes attempt to retain the sericin, the essential problems have not been solved, the product is troublesome to use and maintain, and its application range is limited. Summary of the Invention

[0010] Object of the Invention: The present invention provides a silk sericin preservation process and high-sericin silk. This process enables most of the sericin to be retained in the cocoon or raw silk white blank after treatment, and the sericin is not easily dissolved and lost in subsequent processes. At the same time, it ensures its soft hand feeling, improves the utilization rate of silk and the dyeing uniformity, reduces environmental pollution, and expands the style and application range of silk fabrics.

[0011] Technical Solution

[0012] In the first aspect, the present application provides a silk sericin preservation process:

[0013] A silk sericin preservation process includes the following preparation steps:

[0014] Immerse the raw silk white blank in the treatment solution, react at 90 - 100 °C in a water bath for 1 - 2 h to fully fix the sericin, and then successively perform water washing, degumming, and rinsing to obtain high-sericin silk; the treatment solution is 1 - 5 wt% aqueous acrylic resin, 0.5 - 3 wt% guanidine salt, and 5 - 10 wt% silane-modified polyurethane with the balance being water.

[0015] Further, the treatment solution is 2 - 5 wt% aqueous acrylic resin, 0.5 - 3 wt% guanidine salt, and 5 - 8 wt% silane-modified polyurethane with the balance being water.

[0016] Further, the treatment solution is 2 - 4 wt% aqueous acrylic resin, 1 - 2 wt% guanidine salt, and 5 - 8 wt% silane-modified polyurethane with the balance being water.

[0017] Further, the bath ratio of the raw silk white blank immersed in the treatment solution is 1:(10 - 30).

[0018] Further, the aqueous acrylic resin includes one or a combination of more of hydroxyethyl acrylate copolymer, hydroxypropyl acrylate copolymer, and polyethylene glycol-modified hydroxyethyl acrylate copolymer.

[0019] Further, the aqueous acrylic resin is a styrene-acrylic emulsion type aqueous acrylic resin.

[0020] Furthermore, the silane-modified polyurethane includes one of SX3430E, SX6735D, S888E, GENIOSIL® STP~E15, STP~E35 of AGC Inc.; SPUR+* 1015, SPUR+* 3030, SPUR+* 3040 of Momentive Performance Materials Inc.

[0021] Furthermore, the guanidine salt includes one or a combination of several of guanidine hydrochloride, guanidine nitrate, guanidine carbonate, guanidine nitrate.

[0022] Furthermore, the degumming process is as follows:

[0023] Place the raw silk white blank after washing and drying in a 0.2% sodium carbonate solution, boil it at 95 °C for 30 - 60 min, and the bath ratio is 1:(50 - 100).

[0024] Furthermore, the rinsing process is to place the degummed raw silk white blank in boiling water at 100 °C and boil it for 10 - 30 min.

[0025] In a second aspect, the present application provides a high-sericin silk:

[0026] The high-sericin silk of the present application is prepared by using the silk sericin preservation process of the present application.

[0027] Beneficial effects: 1. A silk sericin preservation process, including the following preparation steps: Immerse the raw silk white blank in a treatment solution to fully fix the sericin, then successively perform water washing, degumming and rinsing to obtain high-sericin silk; the treatment solution includes 1.5 - 3 wt% waterborne acrylic resin, 1 - 2 wt% guanidine salt, 5 - 10 wt% silane-modified polyurethane and the balance water; make the crosslinking agent fully penetrate into the interior of the raw silk white blank through chemical crosslinking method, and then under specific conditions, the waterborne acrylic resin and the silane-modified polyurethane fully react with the sericin to form a molecular entanglement structure, change the chemical structure and properties of the sericin, reduce its water solubility, improve the anti-boiling and alkali resistance ability, thereby realizing the fixation of the sericin, and at the same time improving the hand feeling of the raw silk white blank product.

[0028] 2. Further use an appropriate amount of guanidine salt to reduce the sericin that is not combined with the amino resin and the silane-modified polyurethane during the sericin preservation process, further improve the hand feeling of the high-sericin silk and reduce the uneven dyeing of the high-sericin silk (the second point, highlighting the role of the guanidine salt in the cooperation of the waterborne acrylic resin, the guanidine salt and the silane-modified polyurethane). Specific Embodiments

[0029] To make the technical solutions of the present invention clearer, the following further describes the present invention in detail with specific embodiments.

[0030] Example 1, a silk gum-preserving process, includes the following preparation steps:

[0031] Gum-preserving process: The raw silk blank (using gold silk, 22.5 momme) and the treatment liquid are reacted at a water bath ratio of 1:20 in a 95 °C water bath for 1.5 h to fully fix the sericin. The treatment liquid is 2.5 wt% water-soluble styrene-acrylic emulsion type waterborne acrylic resin (average molecular weight of 8600), 2 wt% guanidine hydrochloride, and 8 wt% silane-modified polyurethane (using Momentive's SPUR+*1015) and the balance of water.

[0032] Washing process: The raw silk blank after the water bath reaction is washed 5 times with water to remove the cross-linked reactants that have not fully reacted on the surface of the raw silk blank.

[0033] Degumming process: The fully dried raw silk blank after washing is placed in a 0.2% sodium carbonate solution and boiled at 95 °C for 50 min, with a bath ratio of 1:80.

[0034] Rinsing process: The degummed raw silk blank is boiled in boiling water at 100 °C for 10 min and repeated 3 times to remove the residual alkali agent, and high-sericin silk is obtained after drying.

[0035] Example 2, a silk gum-preserving process, includes the following preparation steps:

[0036] Gum-preserving process: The raw silk blank and the treatment liquid are reacted at a water bath ratio of 1:10 in a 90 °C water bath for 2 h to fully fix the sericin. The treatment liquid is 1.5 wt% water-soluble styrene-acrylic emulsion type waterborne acrylic resin, 1 wt% guanidine carbonate, and 10 wt% silane-modified polyurethane (using Momentive's SPUR+*3030) and the balance of water.

[0037] Washing process: The raw silk blank after the water bath reaction is washed 3 times with water to remove the cross-linked reactants that have not fully reacted on the surface of the raw silk blank.

[0038] Degumming process: The fully dried raw silk blank after washing is placed in a 0.5% sodium carbonate solution and boiled at 90 °C for 60 min, with a bath ratio of 1:100.

[0039] Rinsing process: The degummed raw silk blank is boiled in boiling water at 100 °C for 10 min and repeated 2 times to remove the residual alkali agent, and high-sericin silk is obtained after drying.

[0040] Example 3, a silk gum-preserving process, includes the following preparation steps:

[0041] Glue retention process: The raw silk blank is reacted with the treatment liquid at a water bath ratio of 1:30 in a 90 °C water bath for 1 h to fully fix the sericin. The treatment liquid is 3 wt% water-soluble styrene-acrylic emulsion type waterborne acrylic resin, 2 wt% guanidine carbonate, and 5 wt% silane-modified polyurethane (using Momentive's SPUR+* 3030), with the balance being water.

[0042] Washing process: The raw silk blank after the water bath reaction is washed 5 times with water to remove the cross-linked reactants that have not fully reacted on the surface of the raw silk blank.

[0043] Degumming process: The fully dried raw silk blank after washing is placed in a 0.1% sodium carbonate solution and boiled at 98 °C for 30 min, with a bath ratio of 1:50.

[0044] Rinsing process: The degummed raw silk blank is placed in boiling water at 100 °C and boiled for 10 min, and this is repeated 3 times to remove the residual alkali agent. After drying, high-sericin silk is obtained.

[0045] Example 4, A silk glue retention process, which is different from Example 1 in that the dosage of the styrene-acrylic emulsion type waterborne acrylic resin in the treatment liquid is 1 wt%.

[0046] Example 5, A silk glue retention process, which is different from Example 1 in that the dosage of the styrene-acrylic emulsion type waterborne acrylic resin in the treatment liquid is 3 wt%.

[0047] Example 6, A silk glue retention process, which is different from Example 1 in that the dosage of the styrene-acrylic emulsion type waterborne acrylic resin in the treatment liquid is 4 wt%.

[0048] Example 7, A silk glue retention process, which is different from Example 1 in that the dosage of the styrene-acrylic emulsion type waterborne acrylic resin in the treatment liquid is 5 wt%.

[0049] Example 8, A silk glue retention process, which is different from Example 1 in that the dosage of guanidine hydrochloride in the treatment liquid is 0.5 wt%.

[0050] Example 9, A silk glue retention process, which is different from Example 1 in that the dosage of guanidine hydrochloride in the treatment liquid is 3 wt%.

[0051] Comparative Example 1, A silk glue retention process, which is different from Example 1 in that the styrene-acrylic emulsion type waterborne acrylic resin is not used in the treatment liquid.

[0052] Performance testing

[0053] Samples:

[0054] Test samples: Silk samples after degumming treatment using Examples 1 to 9;

[0055] Control sample: silk sample after degumming treatment using the comparative example;

[0056] Reference sample: silk sample without degumming treatment.

[0057] 1. Dissolution rate:

[0058] The dissolution rate is calculated by the following formula: Dissolution rate = (W1 - W2) / W1 * 100%;

[0059] Where, W1 is the dry weight of the silk sample before treatment, and W2 is the dry weight of the silk sample after degumming treatment using the example or comparative example; the negative sign indicates an increase in the dry weight after degumming treatment following the sizing treatment. The smaller the dissolution rate, the better the sizing effect. The experimental results are shown in Table 1.

[0060] 2. Conditions when encountering boiling water and weak alkali:

[0061] Respectively place the test sample, the comparative example sample, and the blank sample in boiling water that has been boiling for 10 min, and observe and feel the state changes of the samples and the mass loss before and after treatment. The experimental results are shown in Table 2.

[0062] Respectively place the test sample, the comparative example sample, and the blank sample in a sodium carbonate solution with a concentration of 2 g / L for 10 min, and observe and feel the state changes of the samples and the mass loss before and after treatment. The experimental results are shown in Table 2.

[0063] Table 1. List of test results of the dissolution rate of silk samples obtained using Examples 1 - 9 and Comparative Example 1

[0064] Group Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Dissolution Rate (%) 21.28 1.69 16.76 2.06 6.81 -1.12 -1.35 -1.83 4.37 6.65

[0065] As shown in the data of different examples in Table 1, the larger the dissolution rate value, the more sericin is dissolved and the worse the sizing effect. Therefore, Examples 1, 3, 5, 6, and 7 have relatively good sizing effects. The dissolution of more than 20% in Comparative Example 1 indicates that almost all the sericin has been removed and it is almost impossible to size.

[0066] Table 2. List of changes in silk samples obtained using Examples 1 - 9, Comparative Example 1, and reference silk samples after treatment with boiling water and alkali solution

[0067] Performance Index Examples 1 - 9 Comparative Example Sample Control Sample Condition when Exposed to Boiling Water No change in hardness and softness, and basically no loss in mass Hardened, with a mass loss of 3 - 8% Sericin peeled off, hardened after drying, with a mass loss of 10 - 15% Condition when Exposed to Weak Alkali No change in hardness and softness, and basically no loss in mass Sericin peeled off, softened after drying, with a mass loss of 10 - 20% All sericin removed, softened after drying, with a mass loss of 20 - 25%

[0068] Conduct performance testing on the example samples, the comparative example samples, and the blank samples.

[0069] 3. Warp splitting:

[0070] Conduct warp splitting detection on the silk fabric using GB / T 21294 - 2024. The test results are shown in Table 3.

[0071] 4. Softness and Color

[0072] According to the factory inspection process, the factory inspector manually observes and evaluates the hand softness of the silk fabric by touching it with hands.

[0073] The inspection method is as follows:

[0074] The inspector has more than 2 years of inspection experience and grades the silk fabric.

[0075] Each inspector randomly samples 10 times for each roll of silk fabric. Each sampling takes an area of 30×30 cm as the unit sampling area, and evaluates the hand softness and color of the test sample. Two inspectors evaluate according to the aforementioned evaluation method, and the scoring results are averaged. The results are shown in Table 3; the scoring criteria are as follows:

[0076] 1 point: The soft hand feeling and color are significantly inferior to the original silk fabric, with obvious differences that affect sales. The fabric cannot be sold even after being downgraded.

[0077] 1 - 2 points (excluding 2): The soft hand feeling and color are inferior to the original silk fabric. The fabric can be sold after being downgraded.

[0078] 2 - 3 points (excluding 3): The soft hand feeling and color are slightly inferior to the original silk fabric, but no downgrading is required.

[0079] 3 - 4 points: The soft hand feeling and color are slightly indistinguishable from the original silk fabric, and no downgrading is required.

[0080] Table 3. List of evaluation results of warp splitting, softness and color performance of silk fabrics in Examples 1 - 9 and Comparative Example 1

[0081] Group Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Comparative Example 1 Control Group Warp Dipping (mm) 1.75 1.88 1.78 1.80 1.72 1.71 1.68 1.77 1.81 1.90 1.91 Handfeel and Color 4 2.5 4 3.6 4 4 4 3.8 3.5 2 -

[0082] In this application, the high sericin silk is treated with a treatment solution. The treatment solution uses a compatibility of waterborne acrylic resin, guanidine salt and silane - modified polyurethane, and further optimizes the dosages of the waterborne acrylic resin, guanidine salt and silane - modified polyurethane, so that the obtained silk retains a high amount of sericin. At the same time, the obtained silk and silk fabric have high mechanical properties, softness, dyeing glossiness and relatively uniform dyeing properties, making the obtained silk and silk fabric have excellent comprehensive properties.

[0083] As shown in Table 3 for the data of different embodiments, when the gum retention effect is good, the adhesion between the silk threads is enhanced, making the silk threads less likely to slip. In this case, the splitting data of the fabric will decrease, that is, the anti-splitting performance is enhanced. In addition, when the sericin is completely removed, the silk fabric will lose its original color and become soft. Without gum retention treatment, the remaining sericin will make the hand feel hard, and the higher the score for retaining the sericin while maintaining a soft hand feel after gum retention treatment; therefore, Examples 1, 3, 5, 6, and 7 have relatively good gum retention effects; more preferably, Examples 1, 3, 5, and 6.

[0084] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the appended claims.

Claims

1. A silk rubber preservation process, characterized in that: The method comprises the following preparation steps: The raw silk blank is immersed in a treatment liquid, reacted in a water bath at 90-100° C. for 1-2 hours to allow the sericin to be fully fixed, and then washed, degummed and rinsed in sequence to obtain silk with a high sericin content; the treatment liquid is 1-5wt% of an aqueous acrylic resin, 0.5-3wt% of a guanidine salt, 5-10wt% of a silane-modified polyurethane and the balance is water; The acrylic resin comprises a combination of one or more of hydroxyethyl acrylate copolymer, hydroxypropyl acrylate copolymer and polyethylene glycol-modified hydroxyethyl acrylate copolymer; the acrylic resin is a styrene-acrylic emulsion type water-based acrylic resin.

2. The silk glue preservation process according to claim 1, characterized in that: The treatment liquid comprises 2-5wt% of water-based acrylic resin, 0.5-3wt% of guanidine salt, 5-8wt% of silane-modified polyurethane and the balance of water.

3. The silk glue preservation process according to claim 2, characterized in that: The treatment liquid comprises 2-4 wt % of water-based acrylic resin, 1-2 wt % of guanidine salt, 5-8 wt % of silane-modified polyurethane and the balance of water.

4. The silk glue preservation process according to claim 1, characterized in that: The bath ratio of the raw silk blank immersed in the treatment liquid is 1:(10-30).

5. The silk glue preservation process according to claim 1, characterized in that: The silane-modified polyurethane includes SX3430E, SX6735D, S888E, GENIOSIL® STP E15, STP E35 of AGC Corporation; SPUR+* 1015, SPUR+* 3030, SPUR+* 3040 of Momentive Corporation; and the guanidine salt includes guanidine hydrochloride, guanidine nitrate, guanidine carbonate, guanidine nitrate, or a combination of the two or more thereof.

6. The silk glue preservation process according to claim 1, characterized in that: The degumming process is as follows: The washed and dried raw silk blank is placed in a 0.1-0.5% sodium carbonate solution and boiled at 90-98°C for 30-60 min, with a bath ratio of 1:(50-100).

7. The silk glue preservation process according to claim 1, characterized in that: The rinsing process is to boil the degummed raw silk blank in 100°C boiling water for 10-30 minutes.

8. Silk prepared by the silk glue preservation process according to any one of claims 1 to 7.