A method for controlling the stripping process of special animal fibers and identifying fiber types

Abstract

This invention belongs to the field of animal fiber processing and testing technology, and relates to a method for controlling the color stripping process and identifying the fiber type of special animal fibers. The method first obtains the initial color parameters, average fineness parameters, and scale contrast parameters of the fiber to be treated, and selects the corresponding process window from a preset color stripping parameter matrix accordingly. Then, it sequentially performs a first-stage reduction release bath pre-stripping, an intermediate water wash, and a second-stage acidic oxidation bath main stripping. During the main stripping process, dual endpoint control is performed using oxidation-reduction potential and online color difference change rate. After stripping, a termination reduction wash is performed, and the stripping response characteristics are output. These response characteristics are then fused with morphological and / or spectral characteristics to achieve the identification of the type of special animal fiber. This invention has the advantages of stable stripping effect, minimal fiber damage, strong process adaptability, and high identification accuracy.

Description

Technical Field

[0001] This invention belongs to the field of animal fiber processing and testing technology, specifically relating to a method for controlling the color stripping process of special animal fibers and identifying fiber types. Background Technology

[0002] Specialty animal fibers, especially cashmere, are widely used in high-end textiles due to their fineness, softness, and excellent warmth. However, in actual production, cashmere and other specialty animal fibers often require stripping treatment due to their dark natural color, previous dyeing rework, uneven color, contamination with discolored fibers, or reprocessing. This is to reduce the impact of the original pigments or dyes on subsequent light-colored dyeing and finishing, and to ensure product consistency. Furthermore, there is a need for type identification of animal fibers such as cashmere, sheep wool, yak wool, and camel wool during raw material procurement, sorting and blending, quality control, and trade, especially in dark-colored samples, dyed samples, or samples that have undergone chemical finishing, where apparent differences are weakened, making accurate identification difficult. Therefore, how to achieve stable stripping while minimizing fiber damage and further improve the identifiability of different specialty animal fibers has become a pressing technical problem to be solved in this field.

[0003] Existing technologies already include publicly available solutions for the stripping treatment of cashmere. For example, Chinese patent CN108085958A discloses a cashmere stripping process that employs a multi-stage approach: reduction and release, followed by oxidation bleaching, and then reduction stabilization. The process sequentially uses components such as a pigment separating agent, cashmere protectant, complexing stabilizer, sodium hydrosulfite, and hydrogen peroxide to improve the whiteness after stripping and reduce the rate of whiteness reduction. This solution demonstrates that, for protein fibers like cashmere, a combination of reduction and oxidation stages can, to a certain extent, balance stripping effectiveness and fiber protection.

[0004] Based on existing technologies, current technologies mainly revolve around the single objective of "how to complete the color stripping", and their process settings are closer to fixed procedures for specific sample conditions. For cashmere and other specialty animal fibers with complex origins, significant differences in dyeing depth, fineness, and surface scale conditions in actual production, directly applying the same stripping formula and temperature and time regime can easily lead to the following problems: First, the stripping susceptibility and tolerance of different batches of samples vary significantly, making it difficult to balance sufficient stripping with fiber damage control in a fixed process. This can easily result in insufficient stripping, decreased strength, scale damage, rough hand feel, or subsequent yellowing. Second, existing processes often rely on empirically set holding times as the endpoint control basis, lacking real-time characterization of the stripping process. This makes it difficult to accurately determine when to stop the machine, which is particularly detrimental to the stable processing of high-value-added cashmere. Third, existing stripping schemes typically separate the stripping process from fiber type identification, failing to transform the response differences generated during the stripping process into effective characteristics that can be used to identify different specialty animal fibers such as cashmere, yak wool, and camel wool. This makes it difficult to simultaneously meet the dual needs of production control and raw material identification.

[0005] Therefore, current technology still lacks a method that can adjust the stripping agent formulation and stripping process conditions based on the initial state of the sample for cashmere and other specialty animal fibers, and output response characteristics that can be used for fiber type identification while achieving good stripping results. How to establish an integrated technical solution that balances stripping effect, fiber protection, and type identification remains a technical issue that requires further research and resolution in this field. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide a process control and identification method that can adaptively adjust the stripping agent formulation and stripping process conditions according to the initial state of the fiber, thereby improving the accuracy of identifying special animal fiber types while achieving gentle and efficient stripping.

[0007] To achieve the above-mentioned technical objectives, the present invention provides the following technical solutions.

[0008] In a first aspect, the present invention provides a method for controlling the color stripping process of special animal fibers, comprising the following steps: S1. Obtain the initial color parameters, average fineness parameters, and scale contrast parameters of the special animal fiber to be processed; S2. Based on the initial color parameters, average fineness parameters, and scale comparison parameters, select the corresponding process window from the preset peeling parameter matrix to determine the formula and process conditions of the first-stage reduction release bath and the second-stage acidic oxidation bath. S3. In the first stage reduction and release bath, the special animal fibers to be treated are pre-peeled and then washed with water. S4. In the second stage acidic oxidation bath, the special animal fibers after intermediate water washing are subjected to main stripping treatment. During the main stripping process, the oxidation-reduction potential of the bath liquid and the online color difference change rate of the sample are monitored in real time. When the oxidation-reduction potential enters the preset range and the online color difference change rate continuously reaches the platform criterion, the main stripping is terminated. S5. Perform a termination reduction wash on the special animal fibers after primary color stripping and output a color stripping response vector. The color stripping response vector includes at least the whiteness increment, overall color difference, mass loss rate, strength retention rate, and scale contrast change.

[0009] Specifically, the special animal fiber includes at least one of cashmere, yak wool, camel wool, and rabbit wool; the initial color parameter is the CIE-L*a*b*color coordinates of the sample; the average fineness parameter is the average diameter of the fiber; and the scale contrast parameter is the grayscale difference between the scale edge region and the substrate region in the longitudinal microscopic image of the fiber.

[0010] Specifically, the first-stage reduction and release bath includes thiourea dioxide, sodium hydrosulfite, an acidity regulator, a penetrant, and a protein protectant. The amount of thiourea dioxide added is 8% to 25% of the weight of the fiber to be treated, the amount of sodium hydrosulfite added is 2% to 8% of the weight of the fiber to be treated, the amount of penetrant added is 1% to 4% of the weight of the fiber to be treated, and the amount of protein protectant added is 0.5% to 3% of the weight of the fiber to be treated. The acidity regulator is used to adjust the pH of the bath solution to 4.2 to 5.2.

[0011] Specifically, the first-stage reduction release bath has a bath ratio of 1:20 to 1:60, a treatment temperature of 35 to 50°C, and a treatment time of 15 to 35 minutes; the second-stage acidic oxidation bath includes hydrogen peroxide, a pyrophosphate buffer-complexing component, a penetrant, and an organic acid activating component, wherein the concentration of hydrogen peroxide is 4 to 10 mL / L, the concentration of the pyrophosphate buffer-complexing component is 0.8 to 2.5 g / L, the concentration of the penetrant is 0.5 to 2.0 g / L, and the concentration of the organic acid activating component is 3 to 10 g / L.

[0012] Specifically, the pH of the second-stage acidic oxidation bath is 5.2–6.2, the treatment temperature is 50–65°C, and the treatment time is 20–50 min; the preset range of the oxidation-reduction potential is 280–420 mV, and the platform criterion is that the online comprehensive color difference change rate does not exceed a preset threshold within 3–8 min continuously; the termination reduction wash treatment uses thiourea dioxide, sulfite, or a combination thereof, the treatment temperature is 25–40°C, and the treatment time is 10–20 min.

[0013] Furthermore, the present invention also discloses a method for identifying fiber type, employing the special animal fiber stripping and color control method described in the first aspect, comprising the following steps: T1. Perform decolorization treatment on the special animal fiber to be tested according to the method described in the first aspect, and obtain the corresponding decolorization response vector; T2. Collect fiber morphology and / or spectral data after stripping treatment; T3. Fuse the stripping response vector with the morphological feature data and / or spectral feature data to form a feature set to be judged; T4. Input the set of features to be discriminated into the pre-built classification model and output the fiber type identification result.

[0014] Specifically, the peeling response vector includes at least five of the following: whiteness increment, overall color difference, quality loss rate, strength retention rate, scale contrast change, and redox potential integral value during the main peeling stage; the morphological feature data includes at least two of the following: average diameter, scale density, scale length, and scale curl angle.

[0015] Specifically, the spectral feature data is at least one of near-infrared spectral feature data, infrared spectral feature data, or Raman spectral feature data; the classification model is at least one of support vector machine model, random forest model, partial least squares discriminant model, or neural network model.

[0016] Specifically, the fiber type identification results are used to distinguish two or more of cashmere, sheep wool, yak wool, camel wool, and rabbit wool; the feature set to be judged includes at least whiteness increment, comprehensive color difference, mass loss rate, strength retention rate, scale contrast change, average diameter, and spectral principal component score.

[0017] Specifically, when the classification confidence level output by the classification model is lower than a preset threshold, DNA analysis is invoked for verification in order to further identify cashmere, sheep wool, yak wool and their mixtures.

[0018] This invention introduces the initial color parameters, average fineness parameters, and scale contrast parameters of the special animal fibers to be treated into the stripping process selection process, establishing a stripping parameter matrix adapted to the sample state. It employs a segmented processing mechanism of "first-stage reduction release, second-stage acidic oxidation," combined with dual endpoint control of the redox potential and online color difference change rate in the main stripping stage. This allows for the step-by-step release and directional removal of color particles on the fiber surface and internally, avoiding the problems of insufficient stripping or excessive oxidation commonly found in traditional fixed-formula, fixed-time processes. Furthermore, this invention extracts stripping response characteristics such as whiteness increment, overall color difference, mass loss rate, strength retention rate, and scale contrast change, using these as important inputs for fiber type identification. This enables the stripping process to achieve gentle, efficient, and stable stripping of cashmere and other special animal fibers, and transforms the response differences of different fibers during the stripping process into identifiable features, thereby significantly improving the accuracy and practicality of fiber type identification. Therefore, this invention has comprehensive technical advantages including good stripping effect, minimal fiber damage, strong process adaptability, and high identification capability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall process of the method of the present invention.

[0020] Figure 2 This is a schematic diagram of the steps in the color stripping process control method of the present invention. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0022] I. Technical Solution Description 1.1 General Description This invention provides a method for controlling the color stripping process of special animal fibers and identifying fiber types, which is particularly suitable for cashmere and can be extended to yak wool, camel wool, rabbit wool and some protein fiber samples similar to sheep wool.

[0023] like Figure 1As shown, this invention generally comprises two interconnected parts: special animal fiber stripping process control and fiber type identification. First, the initial color parameters, average fineness parameters, and scale contrast parameters of the special animal fiber to be treated are acquired, and the corresponding process window is selected based on the stripping parameter matrix. Then, the following steps are performed sequentially: a first-stage reduction release bath pre-stripping, intermediate water washing, a second-stage acidic oxidation bath main stripping, a final reduction wash, and the output of the stripping response vector. Based on this, morphological feature data and / or spectral feature data are collected to construct a feature set to be identified, which is then input into a classification model, ultimately outputting the fiber type identification result.

[0024] like Figure 2 As shown, the special animal fiber stripping process control method of the present invention includes steps S1 to S5, wherein step S1 is to obtain initial color parameters, average fineness parameters and scale contrast parameters; step S2 is to select a process window according to the stripping parameter matrix; step S3 is to perform a first-stage reduction release bath pre-stripping and intermediate water washing; step S4 is to perform a second-stage acidic oxidation bath main stripping and monitor the oxidation-reduction potential and online color difference change rate; when the oxidation-reduction potential enters the preset range and the online color difference change rate continuously reaches the platform criterion, step S5 is executed, that is, to perform a termination reduction wash and output the stripping response vector.

[0025] Compared with existing methods that rely solely on fixed stripping formulas, fixed processing times, or single morphology / spectral identification, this invention unifies stripping process control and fiber type identification into a single technology chain: first, a stripping parameter matrix is ​​selected based on the initial state of the sample; then, a stable, mild, and discriminative stripping response vector is obtained through two-stage stripping and dual endpoint control; finally, this response vector is fused with morphological and spectral features to establish a type discrimination model for different special animal fibers.

[0026] To enable those skilled in the art to implement this invention without creative effort, the following will provide a detailed explanation in five levels: terminology explanation, testing conditions and evaluation standards, process implementation path, examples and comparative examples, and technical effect verification.

[0027] 1.2 Explanation of relevant terms To make the technical solution of the present invention clearer, the main terms involved in the specification will be explained first.

[0028] 1.2.1 Initial Color Parameters Initial color parameters refer to the comprehensive color characterization parameters of the special animal fiber sample to be peeled before processing, preferably represented using the CIE-Lab* color space, where, Indicates brightness, Represents the red-green axis chromaticity coordinates. This represents the yellow-blue axis chromaticity coordinates. This parameter is used to characterize the dyeing depth, overall color bias, and subsequent stripping difficulty of the fiber sample.

[0029] 1.2.2 Average Fineness Parameter The average fineness parameter refers to the average diameter of the fiber sample, measured in units of... In this invention, the average fineness parameter is used to reflect both the softness of the fiber and its tolerance to oxidation and reduction treatments. Generally speaking, the smaller the fineness, the softer the fiber, and the more sensitive it is to excessively strong stripping conditions.

[0030] 1.2.3 Scale Comparison Parameters The scale contrast parameter refers to the statistical measure of the grayscale difference between the scale edge region and the scale substrate region in a longitudinal microscopic image of a fiber. This parameter reflects the clarity of the scales on the fiber surface, the integrity of the surface layer, and the degree of surface sealing. It is an important characterizing parameter for the peelability and surface resistance of the bonding process.

[0031] 1.2.4, Peeling Parameter Matrix The peeling parameter matrix is ​​one of the core terms of this invention. It refers to a process mapping table or mapping rule established with initial color parameters, average fineness parameters and scale contrast parameters as input indices. It is used to determine the reagent composition, reagent addition amount, bath ratio, temperature, time and endpoint control threshold of the first-stage reduction release bath and the second-stage acidic oxidation bath.

[0032] 1.2.5 Online color difference change rate Online color difference change rate refers to the rate of change of the overall color difference between two adjacent sampling times during the main color stripping process, denoted as This parameter is used to determine whether the peeling process has entered the plateau region, thus forming a dual endpoint control basis together with the redox potential.

[0033] 1.2.6, Stripping Response Vector The stripping response vector refers to a set of quantifiable features extracted from the process results after the stripping treatment is completed. Preferably, it includes at least the whiteness increment, overall color difference, quality loss rate, strength retention rate, scale contrast change, and the integral value of the redox potential during the main stripping stage. This vector is used both to evaluate the stripping effect and for subsequent fiber type identification.

[0034] 1.2.7 Termination of reduction washing Termination reduction wash refers to a treatment step performed after the main color stripping process, using a gentle reduction system to remove residual oxidative activity, inhibit subsequent yellowing, and stabilize fiber feel and strength.

[0035] 1.2.8 Classification Model A classification model refers to a machine learning model or statistical discriminant model that takes the color stripping response vector, morphological feature data and / or spectral feature data as input and outputs the fiber type result. It is preferably a support vector machine, random forest, partial least squares discriminant model or multilayer perceptron neural network.

[0036] 1.2.9 Type Identification Results The type identification result refers to whether the sample is determined to belong to one of the following categories: cashmere, sheep wool, yak wool, camel wool, or rabbit wool, or whether the output is a mixed discrimination tendency of two or more categories. When the model confidence is insufficient, DNA analysis can be used for further verification.

[0037] II. Experimental conditions, standards adopted, and significance of evaluation indicators In this invention, all samples are preferably conditioned in standard atmosphere before testing to reduce the impact of environmental conditions on color, quality and mechanical properties.

[0038] The sample conditioning and testing environment should be optimized according to GB / T6529-2008 "Standard Atmospheres for Conditioning and Testing of Textiles"; The optimal method for testing fiber whiteness and color is GB / T17644-2008 "Test Method for Whiteness and Color of Textile Fibers"; The breaking strength of special animal fiber bundles should preferably be tested according to GB / T27629-2011 "Test Method for Breaking Strength of Wool Bundle Fibers"; For the microscopic identification of mixtures of special animal fibers and sheep wool, please refer to GB / T16988-2013; DNA verification can be performed in accordance with GB / T40903-2021 "Textile DNA Analysis Method for Identification of Certain Special Animal Fibers: Cashmere, Sheep Wool, Yak Wool and Their Mixtures".

[0039] The detection indicators used in this invention and their significance are as follows.

[0040] 2.1 Whiteness Increment Whiteness increment is used to evaluate the extent to which a sample changes from dark to light or from dull to bright after stripping treatment. For high-value-added animal fibers such as cashmere, a higher whiteness increment means a more thorough stripping process, which is also more conducive to subsequent light-dyeing and high-end worsted spinning applications.

[0041] 2.2 Overall color difference Overall color difference is used to comprehensively characterize the degree of color change before and after color stripping, and is a basic indicator for judging whether color stripping "actually occurred and to what extent." A high overall color difference and a high strength retention rate usually indicate that color stripping is effective and relatively mild.

[0042] 2.3 Quality Loss Rate The mass loss rate reflects the degree of removal of colorants, lipids, impurities, and even keratin from the fiber surface during the stripping process. Moderate mass loss is beneficial for color removal and impurity cleaning; excessive mass loss usually indicates greater fiber damage.

[0043] 2.4, Strength retention rate Strength retention rate is a key indicator for judging whether the stripping process is suitable for actual production applications. For worsted cashmere, if the strength retention rate is low after stripping, the yarn is more prone to breakage, roll wrapping, and uneven yarn formation during subsequent carding, drawing, and spinning processes.

[0044] 2.5. Scale contrast change The change in scale contrast reflects the degree of change in the morphology of the scale layer on the fiber surface. An excessively large absolute value usually indicates severe scale damage, which will affect the softness, fluffiness, and uniformity of cashmere in subsequent dyeing and finishing processes.

[0045] 2.6 ORP integral value during the main color stripping stage The integral value of oxidation-reduction potential (ORP) is used to quantify the cumulative oxidative load during the primary stripping process and is an important variable describing the intensity of the process. It is not only used for process control but also serves as a key characteristic for distinguishing differences in stripping response among different fiber types.

[0046] 2.7 Classification accuracy, macro-average F1 score, classification confidence These metrics are used to evaluate the performance of the fiber type identification model. Among them, accuracy reflects the overall correctness, macro-average F1 reflects the multi-class balance performance, and classification confidence is used to determine whether to trigger DNA retesting.

[0047] Among the above evaluation indicators, the overall color difference, quality loss rate, strength retention rate, and ORP score are calculated as follows: in, , , These are the color coordinates before color stripping. , , These are the color coordinates after color stripping.

[0048] in, The sample's oven-dry mass before processing. The sample is the oven-dry mass after processing.

[0049] in, To address the breaking strength of the front fiber, To address the fracture strength of the rear fiber bundle.

[0050] in, For the first The redox potential value at each sampling time. The interval between adjacent sampling.

[0051] The online color difference change rate is defined as: When continuous Each sampling point satisfies At that time, it is determined that you have entered the platform area; among them, Preferably, there are 3 to 8 time windows, which are the comprehensive color difference change rate thresholds. The preferred value is 0.02 to 0.08.

[0052] III. Raw materials, reagents and equipment 3.1 Fiber raw materials The following samples are preferred in the embodiments, as shown in Table 1.

[0053] Table 1. Sample Table of Animal Fiber Raw Materials 3.2 Pharmaceutical Composition The first-stage reduction and release bath includes: thiourea dioxide, sodium hydrosulfite, acid regulator, penetrant, and protein protectant.

[0054] The second-stage acidic oxidation bath includes: hydrogen peroxide, pyrophosphate buffer-complexing components, penetrants, and organic acid activating components.

[0055] Termination of reduction washing includes: thiourea dioxide and / or sulfites.

[0056] 3.3 Equipment High-temperature small sample staining machine, online ORP sensor, online color difference acquisition module, electronic balance, whiteness colorimeter, projection microscope, digital microscope, fiber strength tester, near-infrared spectrometer, hot air drying oven, data processing terminal.

[0057] IV. Implementation Steps of the Method of the Invention 4.1. S1 Obtain the initial characterization parameters of the fiber to be treated. The main function of S1 is to transform the traditional experience-based judgments of "color depth", "fiber fineness" and "surface integrity" into quantifiable parameters, providing a basis for the automatic or semi-automatic selection of subsequent process windows.

[0058] In practice, 20g of fiber is randomly sampled from each batch of fibers to be treated and divided into three parts: (1) Color test group After spreading the sample, measure its whiteness using a whiteness colorimeter. , , The initial color parameters were obtained by measuring each sample five times and taking the average value. Color testing is preferably conducted in standard atmosphere to avoid measurement deviations caused by differences in sample moisture regain.

[0059] (2) Fineness test group One hundred single fibers were randomly selected, and their diameters were measured using a projection microscope or an automatic image diameter measurement method. After removing obvious outliers, the average value was taken to obtain the average fineness parameter. .

[0060] (3) Morphology test group The samples were prepared for longitudinal microscopic observation, and 20 microscopic images were acquired. Using image analysis software, the scale edge region and scale base region were selected in each image, the grayscale difference was calculated, and the average value was taken to obtain the scale contrast parameters. .

[0061] In this invention, the initial color parameter is used to determine the dyeing depth and overall color bias, the average fineness parameter is used to determine the fiber's resistance, and the scale contrast parameter is used to determine the surface density and surface integrity. These three parameters together constitute the basis for selecting the process window, which is superior to the conventional method of determining the peeling intensity solely based on the overall color depth.

[0062] 4.2 S2 selects the process window from the peeling parameter matrix based on the initial parameters. Unlike traditional stripping methods that use "fixed formula and fixed time", this invention does not use the same stripping process for all cashmere or other special animal fibers. Instead, it selects the most suitable process window from the stripping parameter matrix based on the initial state of the sample.

[0063] 4.2.1 Parameter Matrix Establishment Approach If the stripping process is set solely based on the initial color depth, the strength of dark-dyed fine cashmere is easily reduced due to excessive oxidation. If the process is set based solely on the average fineness, samples of dark-colored yak wool, camel wool, etc., often show insufficient color removal. If scale contrast parameters are introduced in addition to initial color and average fineness, it is possible to simultaneously characterize "color load", "fiber tolerance" and "surface openness", which is more conducive to achieving gentle and stable color peeling.

[0064] Therefore, this invention establishes a three-parameter process matrix: with For longitudinal judgment parameters, average fineness To determine the parameters laterally, and to compare the parameters using scales. Secondary corrections are performed on samples within the same interval.

[0065] 4.2.2 Parameter Matrix Table 2 shows a preferred parameter matrix.

[0066] Table 2 Optimal Process Parameters in, This indicates the initial scale contrast parameters of the fiber to be treated before stripping.

[0067] 4.2.3 Optimal settings for process window content W1 process window: First stage: thiourea dioxide 8%~10% owf, sodium hydrosulfite 2%~3% owf, penetrant 1.0%~1.2% owf, protein protectant 0.8%~1.0% owf, pH 4.8~5.0, treatment temperature 35~38℃, treatment time 15~18min; Second stage: hydrogen peroxide 4-5 mL / L, pyrophosphate buffer-complexing component 0.8-1.0 g / L, penetrant 0.5-0.8 g / L, organic acid activating component 3-4 g / L, treatment temperature 50-53℃, ORP control range 280-330mV.

[0068] W2 process window: First stage: 12% owf of thiourea dioxide, 3% owf of sodium hydrosulfite, 1.5% owf of penetrant, 1.0% owf of protein protectant, pH 4.8, 40℃, 20min; Second stage: 5 mL / L hydrogen peroxide, 1.0 g / L pyrophosphate, 0.8 g / L penetrant, 4 g / L organic acid activating component, 55℃, ORP control range 300~360mV.

[0069] W3 process window: First stage: 18% owf of thiourea dioxide, 5% owf of sodium hydrosulfite, 2.0% owf of penetrant, 1.2% owf of protein protectant, pH 4.6, 45℃, 28min; Second stage: 7 mL / L hydrogen peroxide, 1.6 g / L pyrophosphate, 1.2 g / L penetrant, 6 g / L organic acid activating component, 60℃, ORP control range 330~390mV.

[0070] W4 process window: First stage: 15% owf of thiourea dioxide, 4% owf of sodium hydrosulfite, 1.8% owf of penetrant, 1.0% owf of protein protectant, pH 4.7, 42℃, 24min; Second stage: 6 mL / L hydrogen peroxide, 1.4 g / L pyrophosphate, 1.0 g / L penetrant, 5 g / L organic acid activating component, 58℃, ORP control range 320~380mV.

[0071] With the above matrix, technicians can already implement this invention on common cashmere and other special animal fiber samples; if the sample library increases in the future, the matrix range can be expanded without changing the core idea of ​​the invention.

[0072] 4.3, S3 First Stage Reduction Release Bath Pre-peeling and Intermediate Wash S3 is mainly used to release some of the pigments already attached to the fiber surface and reduce the oxidative stress during the main stripping stage, thereby improving the overall process gentleness. Compared with S2 and S4, S3 has a relatively lower creative contribution, but it plays a significant supporting role in process stability.

[0073] 4.3.1 Composition of the first-stage reagent The preferred first-stage reduction and release bath includes: Thiourea dioxide: 8%~25% owf; Sodium hydrosulfite: 2%~8% owf; Penetrant: 1%–4% owf; Protein protectant: 0.5%–3% owf; Acidity regulator: Adjust the pH of the bath solution to 4.2-5.2.

[0074] Among them, thiourea dioxide and sodium hydrosulfite are used to reduce and release some of the colorants; penetrants are used to improve the penetration of liquid into the interior of the velvet strip; and protein protectants are used to reduce damage to the keratin backbone and surface structure.

[0075] 4.3.2, First Stage Operating Conditions The preferred liquor ratio is 1:20 to 1:60, and more preferably 1:30 to 1:40.

[0076] The preferred processing temperature is 35-50°C, and more preferably, the sample is first wetted at 30°C for 5 minutes before being raised to the set temperature.

[0077] The preferred processing time is 15–35 min.

[0078] 4.3.3 Intermediate water wash After the first stage, drain the liquid and rinse twice with clean water at 35-40℃, 5 minutes each time. The purpose of the intermediate water rinse is to remove the released pigments and reducing agent residues, preventing them from causing side reactions or reducing oxidation efficiency in the second stage.

[0079] 4.4, S4 Second Stage Acidic Oxidation Bath Main Peeling and Dual Endpoint Control Traditional stripping processes often use fixed-time shutdowns as the primary endpoint control method. However, the time required to reach the optimal stripping endpoint varies for different types, dye depths, and surface conditions of specialty animal fibers. Therefore, this invention combines real-time ORP monitoring with an online color difference rate platform as the main criterion for terminating the stripping process.

[0080] 4.4.1 Composition of the second-stage drug The preferred acidic oxidation bath includes: Hydrogen peroxide: 4–10 mL / L; Pyrophosphate buffer-complexing component: 0.8–2.5 g / L; Penetrant: 0.5–2.0 g / L; Organic acid activating component: 3-10 g / L.

[0081] Hydrogen peroxide provides the main oxidation capacity; pyrophosphate has both buffering and complexing functions, which can stabilize the system and inhibit abnormal decomposition caused by metal ions; organic acid activating components are used to regulate the acidic environment and improve oxidation efficiency.

[0082] 4.4.2 Second Stage Process Conditions The preferred pH value is 5.2–6.2; The preferred temperature is 50–65°C; The preferred liquor ratio is 1:20 to 1:50.

[0083] 4.4.3. Principle of Dual Endpoint Control of ORP and Online Color Difference Change Rate (1) The role of ORP ORP is used to reflect the effective oxidation intensity of the current oxidation bath. If the ORP remains below the set range for an extended period, it indicates that the primary stripping dye has not been fully established; if the ORP remains too high for an extended period, it indicates that the fiber is facing an excessively strong oxidizing environment, increasing the risk of damage.

[0084] (2) The role of online color difference change rate ORP alone cannot determine whether the color is close to the plateau zone; however, the online color difference change rate can reflect the color removal speed in real time. When the overall color difference increment continues to decrease and enters the plateau zone, it indicates that the color gain from continuing to extend the processing time is very limited.

[0085] (3) Double endpoint criterion The main peeling process will only terminate if the following conditions are met simultaneously: ORP falls within the preset control range; The online color difference change rate is below the threshold for multiple consecutive sampling periods.

[0086] This strategy can avoid two types of misjudgments: One type is where the ORP has reached the range but the color is still changing rapidly; if the machine is stopped at this point, the color will not be sufficiently stripped. Another type is where the color change tends to plateau, but the ORP has not yet established a stable range. If the system is shut down at this time, it may be a false plateau.

[0087] 4.4.4. An online monitoring system Taking the dark-dyed cashmere sample as an example, the ORP was recorded every 30 seconds during the main stripping stage, and the overall color difference change rate was calculated every 1 minute. The results are shown in Table 3.

[0088] Table 3. 31-minute ORP variation of dark-dyed cashmere As shown in Table 3, in this embodiment, the ORP stabilized in the 330-390mV range from 28 minutes onwards, and the overall color difference change rate continuously entered the plateau region. Therefore, the main color stripping was stopped at 31 minutes. If the time was extended to 40 minutes, the overall color difference only increased slightly, but the strength retention rate decreased further, indicating that dual endpoint control can effectively avoid overprocessing.

[0089] 4.5, S5 Termination Reduction Wash, Post-processing, and Stripping Response Vector Output This step is a crucial bridge connecting process control and fiber type identification.

[0090] 4.5.1 Termination of reduction washing Drain the solution immediately after the main stripping process and add a reduction-stopping wash. Preferred method: Thiourea dioxide: 1.0%–2.0% owf; and / or Sodium bisulfite: 0.3~1.0g / L.

[0091] The preferred processing temperature is 25–40°C, and the processing time is 10–20 minutes. This step can quickly eliminate residual oxidative activity, inhibit subsequent yellowing and further oxidation, and improve the feel and strength retention of the finished product.

[0092] 4.5.2 Post-processing After terminating the reduction wash, it is preferable to wash twice with clean water, and then dry under hot air at 50°C until the moisture content is less than 10%.

[0093] 4.5.3 Construction of the color stripping response vector After processing, the whiteness increment, overall color difference, quality loss rate, strength retention rate, scale contrast change, and ORP integral value of the main peeling stage were measured, and a peeling response vector was constructed. The response vectors formed by different animal fibers under similar stripping conditions show significant differences. For example, cashmere typically exhibits a higher whiteness increment and a higher strength retention rate; yak wool usually has a slightly higher mass loss rate under dark conditions; and camel wool tends to have smaller scale contrast changes. These differences provide novel process-outcome fusion features for subsequent type identification.

[0094] V. Implementation Methods for Fiber Type Identification The following is a structured explanation of the fiber type identification method based on the above-mentioned stripping process control method.

[0095] 5.1. T1 is stripped using the method described in Part 4, and the stripping response vector is obtained. The sample to be tested was processed according to the S1 to S5 processes described above to obtain the corresponding stripping response vector. Ideally, each sample should be processed in triplicate and the average value should be taken to reduce intra-batch variation.

[0096] 5.2. T2 acquisition of morphological and / or spectral characteristics 5.2.1 Morphological characteristics Extract at least two of the following morphological parameters through microscopic image analysis: average diameter ; Scale density ; Scale length ; Scales curled up .

[0097] 5.2.2 Spectral Characteristics Near-infrared spectroscopy was used to scan the samples in the range of 900–1700 nm, with each sample being acquired three times and the average spectrum taken. SNV and first derivative preprocessing were then performed, and the scores of the first six principal components were extracted using PCA. ~ Among them, SNV stands for Standard Normal Variable Transform, which is used to reduce the impact of sample scattering differences and baseline drift on spectral data; PCA is principal component analysis, which is used to compress high-dimensional spectral data into a few principal components that can characterize the main differences, thereby reducing the feature dimension and improving the stability of subsequent classification analysis.

[0098] 5.3, T3 Constructing the Fusion Feature Set The color stripping response vector, morphological features, and near-infrared principal component scores are fused to form a feature set to be discriminated: Ideally, all features should be standardized. in, and These are the mean and standard deviation of the training set, respectively.

[0099] 5.4 T4 Classification Model Establishment and Output The preferred approach is to use a multilayer perceptron neural network, with the following model structure: Input layer: 16-dimensional; Hidden layer 1: 64 neurons, ReLU; Hidden layer 2: 32 neurons, ReLU; Hidden layer 3: 16 neurons, ReLU; Output layer: 5 neurons, Softmax.

[0100] The loss function is cross-entropy: in, Here, c represents the cross-entropy loss value, and c represents the class index. The true label of the sample in class c. The predicted probability of a sample belonging to class c is output by the model; by minimizing This makes the model's output probability distribution as close as possible to the true class distribution of the samples.

[0101] The preferred training parameters are: Optimizer: Adam; Learning rate: ; Batch size: 32; Maximum number of training rounds: 150; Rounds stopped early: 15; Random dropout: 0.2; Weight decay: .

[0102] The sample set preferably includes five categories: cashmere, sheep wool, yak wool, camel wool, and rabbit wool, with 100 batches of each, for a total of 500 batches of samples, which are divided into training set, validation set, and test set.

[0103] The classification output consists of five probability vectors: The category with the highest probability is taken as the discrimination result; when the highest probability is less than 0.75, DNA analysis is used for verification. The DNA verification route is preferably performed in accordance with GB / T40903-2021. VI. Specific Implementation Methods 6.1 Example 1: Stripping and Identification of Dark-Dyed Cashmere Strips The sample is a dark-dyed gray-brown cashmere strip.

[0105] S1 measured: , , , , .

[0106] Based on the parameter matrix, the W3 process window is selected.

[0107] First stage reduction and release bath: 18% owf thiourea dioxide, 5% owf sodium hydrosulfite, 2.0% owf penetrant, 1.2% owf protein protectant, pH 4.6, 45℃, 28 min.

[0108] Intermediate rinse: Rinse twice with 40℃ clean water, 5 minutes each time.

[0109] Second stage acidic oxidation bath: 7 mL / L hydrogen peroxide, 1.6 g / L pyrophosphate, 1.2 g / L penetrant, 6 g / L organic acid activating component, 60℃.

[0110] Endpoint control: ORP 330~390mV and the overall color difference change rate is not higher than 0.05 for 4 consecutive minutes.

[0111] Termination of reduction wash: 1.5% owf thiourea dioxide, 30℃, 12 min.

[0112] 6.2 Example 2: Medium-dyed cashmere slivers The sample is a brown cashmere strip.

[0113] S1 measured: , , .

[0114] The W2 process window is used.

[0115] First stage: 12% owf of thiourea dioxide, 3% owf of sodium hydrosulfite, 40℃, 20min; Second stage: 5 mL / L hydrogen peroxide, 1.0 g / L pyrophosphate, 55℃, ORP control range 300~360mV; The remaining steps are the same as in Example 1.

[0116] 6.3 Example 3: Natural Yak Wool The sample was made of dark brown yak wool.

[0117] S1 measured: , , .

[0118] The W4 process window is used.

[0119] First stage: 42℃, 24min; Second stage: 58℃, ORP control range 320~380mV; The rest is the same as in Example 1.

[0120] 6.4 Example 4: Natural Camel Hair The sample was made of yellowish-brown camel hair.

[0121] S1 measured: , , .

[0122] The W4 and W5 transition process is adopted: the upper limit of W4 is used in the first stage, and the lower limit of W5 is used in the second stage.

[0123] VII. Comparative Example 7.1 Comparative Example 1: Fixed Formula and Fixed Time Method S1 initial parameter detection is not performed, and the S2 parameter matrix is ​​not used; instead, the following is uniformly adopted: First stage: Thiourea dioxide 15% owf, sodium hydrosulfite 4% owf, 45℃, 25min; Second stage: fix with 7 mL / L hydrogen peroxide at 60℃ for 40 min; ORP and online color difference change rate dual endpoint control are not performed.

[0124] 7.2 Comparative Example 2: Elimination of the first stage of pre-peeling Only the second-stage acidic oxidation bath was used, with the same parameters as the second stage of Example 1.

[0125] 7.3 Comparative Example 3: Cancellation of Dual Endpoint Control The same two-stage formulation as in Example 1 was used, but the main peeling color was fixed for 40 minutes.

[0126] 7.4 Comparative Example 4: No stripping response vector used during identification. The classification model is trained using only morphological and near-infrared features, without introducing a color stripping response vector.

[0127] VIII. Experimental Results and Technical Effects 8.1 Comparison of peeling effect and damage control The color stripping effect and damage of the fibers are shown in Table 4. Table 4. Comparison of peeling effects and damage indicators between the examples and comparative examples. As shown in Table 4, compared with Comparative Example 1, Example 1 has a higher whiteness increment and overall color difference, while having a lower quality loss rate and a higher strength retention rate, indicating that the selection of parameter matrix can significantly improve process adaptability. Although Comparative Example 3 has a similar overall color difference, the quality loss rate is significantly higher and the strength retention rate is significantly lower, indicating that there is an over-processing problem in the fixed-time peeling.

[0128] 8.2. Type Identification Model Performance The comparison results of the type identification models are shown in Table 5.

[0129] Table 5. Accuracy of Type Identification Models with Different Feature Combinations As shown in Table 5, after introducing the color stripping response vector, the classification accuracy increased from 93.8% to 97.4%, indicating that the color stripping process of the present invention not only has technological significance, but also generates distinctive response features, thereby improving the ability to identify different types of special animal fibers.

[0130] In summary, this invention, by introducing an initial parameter-driven stripping parameter matrix selection mechanism and combining a segmented processing path of "reduction release—acidic oxidation—termination reduction wash" with dual endpoint control of redox potential and online color difference change rate during the main stripping stage, can not only significantly improve the stripping sufficiency and process stability of cashmere and other special animal fibers, but also effectively control the quality loss rate and strength decline, reduce scale structure damage, and maintain the physical properties required for subsequent fiber processing. Furthermore, this invention integrates the response characteristics, morphological characteristics, and spectral characteristics formed after stripping, significantly improving the accuracy of identifying different types of special animal fibers. This demonstrates that this invention does not simply improve the stripping effect, but rather achieves a synergistic unity between stripping process control and fiber identification capability enhancement, thus possessing significant technological advancement and practical application value.

[0131] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A method for regulating a special animal fiber stripping process, characterized in that, Includes the following steps: S1. Obtain the initial color parameters, average fineness parameters, and scale contrast parameters of the special animal fiber to be processed; S2. Based on the initial color parameters, average fineness parameters, and scale comparison parameters, select the corresponding process window from the preset peeling parameter matrix to determine the formulation and process conditions of the first-stage reduction release bath and the second-stage acidic oxidation bath. S3. In the first stage reduction and release bath, the special animal fibers to be treated are pre-peeled and then washed with water. S4. In the second stage acidic oxidation bath, the special animal fibers after intermediate water washing are subjected to main stripping treatment. During the main stripping process, the oxidation-reduction potential of the bath liquid and the online color difference change rate of the sample are monitored in real time. When the oxidation-reduction potential enters the preset range and the online color difference change rate continuously reaches the platform criterion, the main stripping is terminated. S5. Perform a termination reduction wash on the special animal fibers after primary color stripping and output a color stripping response vector. The color stripping response vector includes at least the whiteness increment, overall color difference, mass loss rate, strength retention rate, and scale contrast change.

2. The method for controlling the stripping and coloring process of special animal fibers according to claim 1, characterized in that, The special animal fiber includes at least one of cashmere, yak wool, camel wool, and rabbit wool; the initial color parameter is the CIE-L*a*b*color coordinate of the sample; the average fineness parameter is the average diameter of the fiber; and the scale contrast parameter is the grayscale difference between the scale edge region and the substrate region in the longitudinal microscopic image of the fiber.

3. The method for controlling the color stripping process of special animal fibers according to claim 1, characterized in that, The first-stage reduction and release bath contains thiourea dioxide, sodium hydrosulfite, an acidity regulator, a penetrant, and a protein protectant. The amount of thiourea dioxide added is 8% to 25% of the weight of the fiber to be treated, the amount of sodium hydrosulfite added is 2% to 8% of the weight of the fiber to be treated, the amount of penetrant added is 1% to 4% of the weight of the fiber to be treated, and the amount of protein protectant added is 0.5% to 3% of the weight of the fiber to be treated. The acidity regulator is used to adjust the pH of the bath solution to 4.2 to 5.

2.

4. The method for controlling the color stripping process of special animal fibers according to claim 1, characterized in that, The first-stage reduction release bath has a bath ratio of 1:20 to 1:60, a treatment temperature of 35 to 50°C, and a treatment time of 15 to 35 minutes. The second-stage acidic oxidation bath contains hydrogen peroxide, a pyrophosphate buffer-complexing component, a penetrant, and an organic acid activating component. The concentration of hydrogen peroxide is 4 to 10 mL / L, the concentration of the pyrophosphate buffer-complexing component is 0.8 to 2.5 g / L, the concentration of the penetrant is 0.5 to 2.0 g / L, and the concentration of the organic acid activating component is 3 to 10 g / L.

5. The method for controlling the stripping and coloring process of special animal fibers according to claim 1, characterized in that, The second stage acidic oxidation bath has a pH of 5.2–6.2, a treatment temperature of 50–65°C, and a treatment time of 20–50 min; the preset range of the oxidation-reduction potential is 280–420 mV, and the platform criterion is that the online comprehensive color difference change rate does not exceed a preset threshold within 3–8 min continuously; the termination reduction wash treatment uses thiourea dioxide, sulfite, or a combination thereof, with a treatment temperature of 25–40°C and a treatment time of 10–20 min.

6. A method for identifying the type of fiber, characterized by, The method for controlling the color stripping process of special animal fibers according to any one of claims 1 to 5 includes the following steps: T1. Perform a color stripping treatment on the special animal fiber to be tested according to any one of claims 1 to 5, and obtain the corresponding color stripping response vector; T2. Collect fiber morphology and / or spectral data after stripping treatment; T3. Fuse the stripping response vector with the morphological feature data and / or spectral feature data to form a feature set to be judged; T4. Input the set of features to be discriminated into the pre-built classification model and output the fiber type identification result.

7. The fiber type identification method according to claim 6, characterized in that, The peeling response vector shall include at least five of the following: whiteness increment, overall color difference, quality loss rate, strength retention rate, scale contrast change, and redox potential integral value during the main peeling stage; the morphological feature data shall include at least two of the following: average diameter, scale density, scale length, and scale curl angle.

8. The fiber type identification method according to claim 6, characterized in that, The spectral feature data is at least one of near-infrared spectral feature data, infrared spectral feature data, or Raman spectral feature data; the classification model is at least one of support vector machine model, random forest model, partial least squares discriminant model, or neural network model.

9. The fiber type identification method according to claim 6, characterized in that, The fiber type identification results are used to distinguish two or more of the following: cashmere, sheep wool, yak wool, camel wool, and rabbit wool; the feature set to be judged includes at least whiteness increment, comprehensive color difference, mass loss rate, strength retention rate, scale contrast change, average diameter, and spectral principal component score.

10. The fiber type identification method according to claim 6, characterized in that, When the classification confidence level output by the classification model is lower than a preset threshold, DNA analysis is invoked for verification in order to further identify cashmere, sheep wool, yak wool and their mixtures.

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