Method for monitoring sizing percentage of slashing on line

Abstract

The invention belongs to the technical field of sizing, and particularly discloses a method for monitoring sizing percentage of sizing on line, which comprises the following steps: modifying hydroxyl-containing textile size to obtain fluorescent recognizable size; sizing the warp yarns by using the fluorescent recognizable sizing agent to obtain sized yarns; the theoretical fluorescence intensity of the slashing under ultraviolet irradiation is obtained, and the theoretical sizing percentage of the slashing is determined according to the theoretical fluorescence intensity. According to the invention, the fluorescence intensity of the sizing can be conveniently and quickly measured in real time, and the sizing percentage of the sizing is determined according to the fluorescence intensity, so that online monitoring of the sizing percentage of the sizing is realized, information of the sizing percentage can be fed back in time, a sizing worker can conveniently adjust sizing process parameters, the operation process is simple, the sensitivity is high, and the accuracy is high. A large number of standard samples do not need to be established and optimized, the yarn quality problem caused by unstable sizing percentage is reduced, intelligent control over the sizing process can be achieved, and the sizing cost is effectively reduced.

Description

Technical Field

[0001] The present invention discloses a method for on-line monitoring of the sizing rate of sized warps, belonging to the technical field of warp sizing. Background Art

[0002] Warp sizing is an essential and important process in textile processing. The sizing rate directly determines the cost of sized warps, and is highly correlated with properties such as abrasion resistance, hairiness, and elongation. Maintaining an appropriate and relatively stable sizing rate is an important means to ensure stable weaving production. During the warp sizing process, the sizing rate is mainly controlled by factors such as slurry temperature, viscosity, warping machine stop time, squeezing pressure, squeezing roller depth, and warping speed. Changes in these factors will seriously affect the uniformity of the warp sizing rate, making the warp prone to stress concentration when subjected to external forces, which is not conducive to enhancing the warp strength, maintaining the warp elongation, and reducing the warp weavability. Therefore, it is of great significance to develop a method for on-line monitoring of the sizing rate of sized warps to timely adjust various factors in the sizing process, so as to improve the sizing quality and achieve efficient weaving.

[0003] Currently, the most traditional method for testing the sizing rate of sized warps is the desizing method. This method cannot on-line monitor the sizing rate of warps, cannot timely adjust various processes in the sizing process, and has problems such as cumbersome operation and long detection time. However, due to its relatively accurate testing, the desizing method is commonly used as a control experiment. On-line testing methods for the sizing rate of sized warps include infrared method, microwave method, capacitance method, etc. Fourier near-infrared spectroscopy analysis technology detects the infrared spectrum of sized warps, and based on the corresponding relationship between the spectral characteristics and the sizing rate, combined with a standard model, on-line detects the sizing rate of warps. However, the accuracy of this method depends on the quality of the calibration model, requires a large number of standard samples to establish and optimize the model, and the instrument equipment is relatively expensive; the microwave method is based on the principle that the absorption of microwaves by sized warps is related to their moisture content, and indirectly obtains the sizing rate by measuring the moisture regain of sized warps to on-line detect the sizing rate of warps. However, this method has strict requirements for the measurement environment, and the transmission and attenuation of microwave signals may be affected by factors such as the motion state of the yarn and the uniformity of yarn distribution, resulting in certain errors in the measurement accuracy; the capacitance method is based on a capacitance sensor. According to the different dielectric constants of yarns with different sizing rates, the capacitance value of the capacitance sensor changes accordingly to monitor the sizing rate of warps. However, this method is easily affected by environmental factors, has a strong model dependence, is sensitive to yarn structures (such as twist, fiber type, blend ratio), and the cost of using instruments is relatively high. Therefore, there is an urgent need to develop a simple, accurate, and stable method for on-line monitoring of the sizing rate of warps. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for on-line monitoring of the sizing rate of sized warps to solve the technical problems of low accuracy and high cost existing in the existing on-line monitoring methods.

[0005] The present invention provides a method for on-line monitoring of the sizing rate of sized yarns, including:

[0006] Modifying a hydroxyl-containing textile sizing agent to obtain a fluorescence-identifiable sizing agent;

[0007] Sizing the warp yarns with the fluorescence-identifiable sizing agent to obtain sized yarns;

[0008] Obtaining the theoretical fluorescence intensity of the sized yarns under ultraviolet light irradiation, and determining the theoretical sizing rate of the sized yarns according to the theoretical fluorescence intensity.

[0009] Preferably, modifying the hydroxyl-containing textile sizing agent specifically includes:

[0010] Introducing a 1,4-dihydropyridine ring into the hydroxyl-containing textile sizing agent.

[0011] Preferably, introducing a 1,4-dihydropyridine ring into the hydroxyl-containing textile sizing agent specifically includes:

[0012] Esterifying the hydroxyl-containing textile sizing agent to obtain an esterified sizing agent;

[0013] Adding an aldehyde compound and an ammonium compound to the esterified sizing agent to cause a Hantzsch reaction of the esterified sizing agent, thereby introducing a 1,4-dihydropyridine ring.

[0014] Preferably, determining the theoretical sizing rate of the sized yarns according to the theoretical fluorescence intensity specifically includes:

[0015] Using an experimental method to pre-determine the mathematical relationship between the fluorescence intensity and the sizing rate of the sized yarns;

[0016] Substituting the theoretical fluorescence intensity into the mathematical relationship to obtain the theoretical sizing rate of the sized yarns.

[0017] Preferably, using an experimental method to pre-determine the mathematical relationship between the fluorescence intensity and the sizing rate of the sized yarns specifically includes:

[0018] Sizing multiple experimental warp yarns with different concentrations of the fluorescence-identifiable sizing agent to obtain multiple experimental sized yarns;

[0019] Determining the sizing rate and fluorescence intensity of the multiple experimental sized yarns;

[0020] Determining the fitting curve of the sizing rate and the fluorescence intensity to obtain the mathematical relationship between the fluorescence intensity and the sizing rate of the sized yarns.

[0021] Preferably, determining the sizing rate and fluorescence intensity of the multiple experimental sized yarns specifically includes:

[0022] Using the desizing method to determine the sizing rate of each experimental sized yarn;

[0023] Obtain the fluorescence intensity of each experimental sized warp under ultraviolet light irradiation.

[0024] Preferably, the concentration of the fluorescent molecules in the fluorescent recognizable sizing agent is 1% - 5%.

[0025] Preferably, the aldehyde compound is at least one of dodecanal, formaldehyde, benzaldehyde, 4-hydroxybenzaldehyde, hexanal, and stearaldehyde.

[0026] Preferably, the ammonium compound is ammonium acetate.

[0027] Preferably, the esterification of the hydroxyl-containing textile sizing agent specifically includes:

[0028] Adding an ester compound to the hydroxyl-containing textile sizing agent to carry out esterification on the hydroxyl-containing textile sizing agent;

[0029] The ester compound is at least one of tert-butyl acetoacetate, ethyl acetoacetate, and propyl acetoacetate.

[0030] The method for on-line monitoring of the sizing rate of sized warps according to the present invention has the following beneficial effects compared with the prior art:

[0031] The present invention can conveniently, quickly, and in real time measure the fluorescence intensity of sized warps, and determine the sizing rate of sized warps according to the fluorescence intensity, so as to realize on-line monitoring of the sizing rate of sized warps. It can timely feedback the information of the sizing rate, facilitate the sizing workers to adjust the sizing process parameters, has a simple operation process, high sensitivity, does not require a large number of standard samples to establish and optimize models, reduces the yarn quality problems caused by unstable sizing rate, can realize the intelligent control of the sizing process of sized warps, and effectively reduces the sizing cost. Description of the Drawings

[0032] Figure 1 It is a flowchart of the method for on-line monitoring of the sizing rate of sized warps in the embodiment of the present invention.

[0033] Figure 2 It is a preparation mechanism diagram of the fluorescent recognizable sizing agent in the embodiment of the present invention.

[0034] Figure 3 It is a fluorescence spectrogram of warp yarns with different sizing rates in the embodiment of the present invention.

[0035] Figure 4 It is a schematic diagram of the fitting curve of sizing rate - fluorescence intensity in the embodiment of the present invention.

[0036] Figure 5 It is a diagram of the combination of the sizing liquid and the sized warp under the stimulation of 365UV of the fluorescence microscope in the embodiment of the present invention.

[0037] Figure 6It is the standard curve graph of sizing rate - fluorescence intensity obtained in Example 1.

[0038] Figure 7 It is the scatter plot distribution graph of sizing rate - fluorescence intensity after changing the squeezing pressure in Example 2.

[0039] Figure 8 It is the scatter plot distribution graph of sizing rate - fluorescence intensity after changing the slurry temperature in Example 3.

[0040] Figure 9 It is the scatter plot distribution graph of sizing rate - fluorescence intensity after changing the warping speed in Example 4.

[0041] Figure 10 It is the standard curve graph of sizing rate - fluorescence intensity of fluorescent PVA in Example 5. Detailed implementation manners

[0042] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are presented to thoroughly understand the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present invention.

[0043] The embodiments of the present invention provide a method for online monitoring of the sizing rate of warped yarns, as Figure 1 and Figure 2 shown, including:

[0044] Step 1: Modify the textile sizing containing hydroxyl groups to obtain a fluorescence - recognizable sizing.

[0045] The fluorescence - recognizable sizing in the embodiments of the present invention is not the fluorescence - recognizable sizing prepared by introducing fluorescence molecules such as fluorescein isothiocyanate (FITC), perylene tetracarboxylic acid (PTCA), epoxy fluorescein (EPF), or aggregation - induced emission (AIE) units into the textile sizing. The fluorescence - recognizable sizing prepared by introducing the above - mentioned fluorescence molecules can only be sized when the concentration of the fluorescence molecule does not exceed 0.0236%. When the concentration is too high, the phenomenon of aggregation fluorescence quenching will occur, and when the concentration is too low, the fluorescence effect will be weak, making it difficult to determine the sizing rate according to the fluorescence intensity.

[0046] In the embodiment of the present invention, the fluorescently recognizable sizing agent is a sizing agent in which a recognizable 1,4-dihydropyridine (DHP) ring is introduced into a hydroxyl group-containing textile sizing agent. After being stimulated by ultraviolet light, the DHP ring in the sizing agent can have a maximum emission wavelength at 480 nm, endowing the sizing agent with recognizable characteristics. Moreover, the concentration of fluorescent molecules in the fluorescently recognizable sizing agent obtained in the present invention is 1% to 5%, and exemplarily, it can be 1%, 2%, 3%, 4%, 5%, etc. The fluorescently recognizable sizing agent within this molecular concentration range can exhibit excellent fluorescence, can solve the problem of aggregation fluorescence quenching of existing fluorescent sizing agents, and will not change the color of the sizing agent itself or affect the color of the yarn; at the same time, the fluorescently recognizable sizing agent has excellent water solubility, fluidity, viscosity stability, film-forming property, and adhesion, and has excellent compatibility with polyacrylamide, polyacrylate, etc.

[0047] Exemplarily, introducing a recognizable 1,4-dihydropyridine (DHP) ring into the hydroxyl group-containing textile sizing agent specifically includes:

[0048] Step 1.1: Esterify the hydroxyl group-containing textile sizing agent to obtain an esterified sizing agent.

[0049] The above-mentioned hydroxyl group-containing textile sizing agent can specifically be starch, polyvinyl alcohol, and acrylic sizing agents.

[0050] Taking starch (acidified starch, oxidized starch, esterified starch, etherified starch can be selected) as an example in the embodiment of the present invention, the esterification of starch specifically is: adding an ester compound to the starch to esterify the hydroxyl group-containing textile sizing agent to obtain an esterified sizing agent. The ester compound can specifically be at least one of tert-butyl acetoacetate, ethyl acetoacetate, and propyl acetoacetate. Exemplarily, if tert-butyl acetoacetate is used, acetoacetate starch containing an acetoacetyl group can be obtained.

[0051] Step 1.2: Add an aldehyde compound and an ammonium compound to the esterified sizing agent to cause the Hantzsch reaction of the esterified sizing agent, thereby introducing a 1,4-dihydropyridine ring.

[0052] The above-mentioned aldehyde compound can specifically be at least one of dodecyl aldehyde, formaldehyde, benzaldehyde, 4-hydroxybenzaldehyde, hexanal, and stearaldehyde; the ammonium compound can specifically be ammonium acetate. When the ratio of ester:aldehyde:ammonium is 0.5 to 1.5:0.1:0.1, the obtained concentration of fluorescent molecules is 1% to 5%.

[0053] Exemplarily, the present invention uses dodecyl aldehyde and ammonium acetate to perform the Hantzsch reaction on the above-mentioned obtained acetoacetate starch, and after repeatedly washing with absolute ethanol and drying, a fluorescently recognizable sizing agent introducing a 1,4-dihydropyridine ring is obtained.

[0054] Step 2: Size the warp yarn with the fluorescently recognizable sizing agent to obtain a sized warp yarn.

[0055] Step 3: Obtain the theoretical fluorescence intensity of the sized yarn under ultraviolet light irradiation, and determine the theoretical sizing rate of the sized yarn according to the theoretical fluorescence intensity, including:

[0056] Step 3.1: Obtain the theoretical fluorescence intensity of the sized yarn under ultraviolet light irradiation.

[0057] The principle of the sized yarn obtained in the embodiment of the present invention emitting fluorescence under ultraviolet light irradiation is as follows:

[0058] 1,4-Dihydropyridine (DHP) rings are introduced into the starch structure. These DHP conjugated rings are closely arranged in the starch molecular chain to form cluster chromophores, which produce fluorescence under ultraviolet stimulation, endowing the starch with an identifiable function. The DHP conjugated ring has a stable fluorescence effect and does not exhibit the aggregation-caused quenching (ACQ) effect. Its luminescence mainly relies on the induction of spatial conjugation by electron interactions, which broadens the energy band, reduces the energy gap, and generates excitons. Subsequently, a series of intra- or intermolecular interactions such as spatial electron transfer, dipole-dipole interaction, and π-π interaction stabilize the excitons, enabling the electrons to radiatively transition back to the ground state. In addition, these interactions promote the delocalization of the lone pair electrons on the nitrogen atom and the π electrons on the carbon in space, facilitating the radiative transition and thus generating fluorescence.

[0059] In the embodiment of the present invention, a fluorescence spectrometer is used to obtain the theoretical fluorescence intensity of the sized yarn under ultraviolet light irradiation.

[0060] Step 3.2: Determine the theoretical sizing rate of the sized yarn according to the theoretical fluorescence intensity, specifically including:

[0061] Step 3.2.1: Using an experimental method, pre-determine the mathematical relationship between the fluorescence intensity and the sizing rate of the sized yarn, specifically including:

[0062] A. Size multiple experimental warp yarns with fluorescently identifiable sizing agents at different concentrations to obtain multiple experimental sized yarns.

[0063] B. Determine the sizing rate and fluorescence intensity of the multiple experimental sized yarns.

[0064] Exemplarily, use the desizing method to test the sizing rate of each experimental sized yarn; and use a fluorescence spectrometer to test the fluorescence intensity of each experimental sized yarn under ultraviolet light irradiation to obtain the fluorescence spectra of sized yarns with different sizing rates. As Figure 3 shown, it can be seen that as the sizing rate of the sized yarn increases, the fluorescence intensity of the maximum emission peak in the fluorescence spectrum diagram shows an upward trend.

[0065] C. Determine the fitting curve of the sizing rate and the fluorescence intensity to obtain the mathematical relationship between the fluorescence intensity and the sizing rate of the sized yarn.

[0066] Exemplarily, the sizing rate and the fluorescence intensity of the maximum emission peak were fitted to establish a mathematical model between the sizing rate and the fluorescence intensity, as Figure 4 shown. It can be seen that when the sizing rate of the sized yarn is lower than 12%, the fluorescence intensity shows a linear upward trend with the increase of the sizing rate; when the sizing rate of the sized yarn is greater than 12%, the change of the fluorescence intensity is not obvious, and the sizing rate of the sized yarn and the fluorescence intensity show a non-linear relationship, and the correlation coefficient is 0.99447. The fitting curve equation is Y = -1626121*e(-X / 4.36649)+1349259. Considering that the change of the fluorescence intensity is not obvious when the sizing rate of the sized yarn exceeds 12%, the method for on-line monitoring the sizing rate of the sized yarn proposed in this embodiment is mainly applicable to the case where the sizing rate of the sized yarn is lower than 12%.

[0067] Step 3.2.2: Substitute the theoretical fluorescence intensity into the mathematical relationship to obtain the theoretical sizing rate of the sized yarn.

[0068] Aiming at the problems in the prior art of detecting the sizing rate of warp yarns, such as strong targeting of sizing agents, cumbersome operation process, easy interference by environmental factors, and the need for a large number of standard samples to establish and optimize models, the present invention proposes a method for on-line monitoring the sizing rate of sized yarns based on fluorescence labeling. This method has great advantages and broad application prospects in modern textile sizing processes.

[0069] First, the fluorescence-identifiable sizing agent prepared by the present invention has universality and is applicable to various textile sizing agents containing hydroxyl groups. It also has excellent luminescence performance and stability. Compared with the method of introducing fluorescent dyes such as FITC, PTCA, EPF, and AIE-based fluorescent molecules into the textile sizing agent structure to achieve the identifiable function, this method solves the problem of aggregation-induced fluorescence quenching faced by existing fluorescent sizing agents, and while achieving stable high-concentration fluorescence emission, it does not affect the color of the yarn itself.

[0070] Second, when evaluating the impregnation and coating properties of the sizing agent on the yarn by the existing method, a sized yarn slice with an appropriate thickness is first prepared, and then the corresponding color developer of the sizing agent is used to color the slice. The cross-sectional morphology of the colored slice is observed with an ordinary optical microscope. Depending on the color photo of the morphology image, the impregnation rate, coating rate, etc. are calculated by using an area integrator or by cutting and weighing the sulfuric acid paper. This method is used to evaluate the impregnation and coating effects of the sizing agent on the yarn. This method has limitations such as low resolution, difficulty in distinguishing the sized yarn interface, inability to determine the distribution of the sizing agent on the colored-spun yarn, and lack of a corresponding color developer for polyacrylic sizing agents. The fluorescence-identifiable sizing agent prepared by the present invention can observe the fluorescence brightness on the surface of the sized yarn according to a fluorescence microscope, as Figure 5As shown, it can be seen that under the ultraviolet light stimulation of the fluorescence microscope, it is very convenient to identify the distribution of the sizing agent on the surface of the yarn. In addition, the fluorescence brightness of the sized yarn cross-section can be observed through the fluorescence microscope, which can easily identify the coating, penetration of the sizing agent into the yarn, and the effect at the junction of the two, without any color developer, and is not restricted by the adaptability of the sizing agent and warp yarn varieties.

[0071] Thirdly, the fluorescence-identifiable sizing agent has excellent water solubility, fluidity, viscosity stability, film-forming property, and adhesion, and has excellent compatibility with polyacrylamide, polyacrylate, etc., which is beneficial to the better combination of the sizing agent and the yarn, and achieves the effects of enhancing elongation retention, improving wear resistance, and making the hairiness obedient.

[0072] Fourthly, for the method of online monitoring the sizing rate based on fluorescence labeling, during the warp sizing process, the spectral brightness analyzer can be placed at a suitable position on the sizing machine to conveniently, quickly, and real-time measure the fluorescence intensity of the sized yarn. According to the established mathematical model between the fluorescence intensity and the sizing rate, the corresponding algorithm program is compiled. When the system obtains the real-time fluorescence intensity data, the fluorescence intensity is substituted into the mathematical model, and the corresponding sizing rate is calculated through the algorithm, so as to realize the online monitoring of the sizing rate of the sized yarn, be able to timely feedback the information of the sizing rate, facilitate the sizing workers to adjust the sizing process parameters, with a simple operation process, high sensitivity, without the need to establish and optimize the model with a large number of standard samples, reduce the yarn quality problems caused by unstable sizing rate, can realize the intelligent control of the warp sizing process, and effectively reduce the sizing cost.

[0073] Fifthly, the method of the present invention for online monitoring the sizing rate of sized yarn is not affected by the external environment (such as temperature, humidity, pressing force, sizing solution temperature, sizing solution viscosity, sized yarn speed, etc.), and has remarkable test accuracy and effectiveness.

[0074] Next, the accuracy and effectiveness of the method of the present invention will be described in more specific embodiments.

[0075] When determining the accuracy and effectiveness in the follow-up of the present invention, the sizing rate error and the sizing rate of the experimental sized yarn determined by the desizing method are used. Among them, the sizing rate error is verified by adjusting the influencing factors of the sizing rate of the sized yarn (pressing force, sizing solution temperature, sizing solution viscosity, sized yarn speed) to verify the accuracy and effectiveness of the method. The calculation formula of the sizing rate error (Er) is as follows:

[0076]

[0077] Among them, x and x 0 respectively represent the theoretical sizing rate and the actual sizing rate of the sized yarn (i.e., the sizing rate of the experimental sized yarn).

[0078] The sizing rate (x 0), Specific method: Put a certain amount of experimental sized yarn in a sodium hydroxide solution with a mass fraction of 2% and boil for about 10 min, then take it out, wash the sample with clean water, and then put it in an oven to dry to a constant weight. The sizing rate (x 0 ) is calculated as follows:

[0079]

[0080] Among them, w and w 0 respectively represent the dry weight of the experimental sized yarn before desizing and the dry weight of the experimental sized yarn after desizing, and β represents the hairiness loss rate.

[0081] The hairiness loss rate (β) is an index to measure the degree of reduction of surface hairiness of the yarn during desizing. Specific test method: Put a certain amount of raw yarn in a sodium hydroxide solution with a mass fraction of 2% and boil for about 10 min, then take it out, wash the sample with clean water, and then put it in an oven to dry to a constant weight. The hairiness loss rate (β) is calculated as follows:

[0082]

[0083] Among them, B and B 0 respectively represent the dry weight of the raw yarn sample before boiling and the dry weight after boiling.

[0084] Example 1

[0085] First, dissolve 20 g of starch in 200 mL of dimethylformamide (DMF) and heat to 90 °C, then slowly drop 47.4 g of tert-butyl acetoacetate (t-BAA) in a closed space, then raise the temperature to 100 °C, and continuously stir and react for 3 h. After completion, precipitate the solution in absolute ethanol, wash the filtered precipitate 3 times with absolute ethanol, and vacuum dry at 50 °C overnight to obtain acetoacetate starch. Secondly, dissolve the acetoacetate starch obtained in the above step in 200 mL of 85% ethanol solution, add 0.772 g of ammonium acetate and 2.3 g of dodecanal, stir at room temperature for 4.5 h, precipitate in absolute ethanol after the reaction, wash 3 times with absolute ethanol after filtration, and vacuum dry the precipitate at 50 °C overnight to obtain fluorescently recognizable starch sizing agent. Finally, size the 14.6 tex pure cotton yarn with the sizing agent prepared from the fluorescently recognizable starch sizing agent. The sizing process parameters are: the sizing agent concentration is 6% - 10%, the sizing agent temperature is 85 °C, the squeezing pressure is 40 N, the sizing agent temperature is 85 °C, the drying room temperature is 70 °C, the sizing trough temperature is 95 °C, the sized yarn speed is 50 m·min -1 , the position of the immersion roller is appropriate, and experimental sized yarns with sizing rates of 6.6%, 7.2%, 8.9%, 10.5%, and 11.6% are obtained. The standard curve of the sizing rate of the experimental sized yarn and the fluorescence intensity is as Figure 6As shown, the sizing rate of the sized yarn is less than 12%, and there is a linear relationship between the sizing rate of the sized yarn and the fluorescence intensity. The correlation coefficient is 0.98969, and the fitting curve equation (mathematical relationship) is Y = 50710X1 + 667632.

[0086] Example 2

[0087] The sized yarn of 14.6 tex pure cotton yarn was sized with the fluorescently recognizable sizing agent prepared in Example 1. The sizing process parameters were as follows: the sizing agent concentration was 8%, the sizing agent temperature was 85 °C, the squeezing pressure was changed to 30 N, 40 N, 60 N, 70 N, 80 N, the drying oven temperature was 70 °C, the sizing trough temperature was 95 °C, and the sized yarn speed was 50 m·min -1 , and the position of the sizing roller was appropriate to obtain sized yarns with different sizing rates. The fluorescence intensities of their maximum emission peaks were measured respectively. According to the fitting curve equation obtained in Example 1, the theoretical sizing rates of the sized yarns obtained under different squeezing pressures were 7.8%, 8.1%, 8.8%, 9.4%, and 9.7% respectively. The sizing rates of the corresponding sized yarns obtained by the desizing method were 7.7%, 8.2%, 8.6%, 9.3%, and 9.8% respectively, as Figure 7 shown in the scatter distribution. From this, it was calculated that the error range of the sizing rate of the sized yarn was between 1.6% and 2.5%.

[0088] Example 3

[0089] The sized yarn of 14.6 tex pure cotton yarn was sized with the fluorescently recognizable sizing agent prepared in Example 1. The sizing process parameters were as follows: the sizing agent concentration was 8%, the sizing agent temperature was changed to 45 °C, 55 °C, 65 °C, 75 °C, 95 °C, the squeezing pressure was 40 N, the drying oven temperature was 70 °C, the sizing trough temperature was 95 °C, and the sized yarn speed was 50 m·min -1 , and the position of the sizing roller was appropriate to obtain sized yarns with different sizing rates. The fluorescence intensities of their maximum emission peaks were measured respectively. According to the fitting curve equation obtained in the example, the theoretical sizing rates of the sized yarns obtained under different drying temperatures were 7.4%, 8.2%, 8.6%, 9.4%, and 9.7% respectively. The sizing rates of the corresponding sized yarns obtained by the desizing method were 7.2%, 7.9%, 8.4%, 9.2%, and 9.4% respectively, as Figure 8 shown in the scatter distribution. From this, it was calculated that the error range of the sizing rate of the sized yarn was between 2.4% and 3.1%.

[0090] Example 4

[0091] The sizing slurry prepared in Example 1 was used to make a sizing solution to size 14.6 tex pure cotton yarn. The sizing process parameters were as follows: the sizing solution concentration was 8%, the sizing solution temperature was 85 °C, the squeezing pressure was 40 N, the drying oven temperature was 70 °C, the sizing tank temperature was 95 °C, and the position of the dipping roller was appropriate. Sized yarns with different sizing rates were obtained. The fluorescence intensities of their maximum emission peaks were measured respectively. According to the fitting curve equation obtained in Example 1, the theoretical sizing rates of the sized yarns obtained at different sized yarn speeds were 8.2%, 8.5%, 8.8%, 9.4%, and 9.8% respectively. The sizing rates of the corresponding sized yarns obtained by the desizing method were 8.0%, 8.3%, 8.6%, 9.2%, and 9.5% respectively, as shown in Figure 9 the scatter distribution in. From this, it was calculated that the error range of the sized yarn sizing rate was between 2.1% and 3.1%.

[0092] Example 5

[0093] To verify the universality of the fluorescently identifiable sizing slurry of the present invention, a fluorescently identifiable polyvinyl alcohol (PVA) sizing slurry was prepared, and the preparation method was as shown in Example 1. The sizing solution made from the fluorescently identifiable PVA sizing slurry was used to size 14.6 tex pure cotton yarn. The sizing process parameters were as follows: the squeezing pressure was 40 N, the sizing solution concentration was 6% - 10%, the drying oven temperature was 70 °C, the sizing tank temperature was 95 °C, the sizing solution temperature was 85 °C, the sized yarn speed was 50 m·min-1, and the position of the dipping roller was appropriate. The standard curve of the sizing rate - fluorescence intensity of the fluorescently identifiable PVA sizing was as shown in Figure 10 shown. It can be seen that the sizing rate of the sized yarn was less than 13%, and there was a linear relationship between the sizing rate of the sized yarn and the fluorescence intensity, with a correlation coefficient of 0.97918. The fitting curve equation was Y = 87351X1 + 237202.

[0094] The monitoring of the sizing rate of the sized yarn by the fluorescently identifiable PVA sizing slurry could range from 6% to 13%, exceeding the sizing rate monitoring range (6 - 12%) of the fluorescently identifiable starch. This was because the PVA molecular chain was relatively regular, the fluorescent groups were more evenly distributed in its structure, and at the same time, the excellent fluidity of the PVA sizing slurry was conducive to the uniform coating and penetration of the fluorescently identifiable PVA sizing slurry on the surface and inside of the yarn, improving the monitoring range of the sizing rate of the sized yarn.

[0095] From the above examples, it can be seen that the error range of the method of the present invention was between 1.4% and 3.1%, indicating that this method could be used for on-line monitoring of the sizing rate of sized yarns, and could effectively improve the control level of the quality of sized yarns, reducing the yarn quality problems caused by unstable sizing rates.

[0096] The present invention prepares a fluorescence-identifiable sizing agent, constructs a mathematical model of the sizing rate of the fluorescence-identifiable sizing agent on warp yarns and fluorescence intensity, proposes a method for realizing on-line monitoring of the sizing rate of warp yarns with a fluorescence-labeled textile sizing agent, and verifies the accuracy and effectiveness of the mathematical model. The main principle is to utilize the relationship between the content of the fluorescence-identifiable sizing agent and fluorescence intensity to on-line monitor the sizing rate of warp yarns according to the magnitude of fluorescence intensity. The method includes the preparation of the fluorescence-identifiable textile sizing agent, the relationship between the sizing rate of warp yarns and fluorescence intensity, and the establishment of a standard curve of sizing rate and fluorescence intensity.

[0097] The present invention can conveniently, quickly and in real time measure the fluorescence intensity of warp yarns, determine the sizing rate of warp yarns according to the fluorescence intensity, thereby realizing on-line monitoring of the sizing rate of warp yarns, being able to timely feedback information on the sizing rate, facilitating the adjustment of warp yarn sizing process parameters by warp yarn workers, having a simple operation process, high sensitivity, not requiring the establishment and optimization of a large number of standard samples, reducing yarn quality problems caused by unstable sizing rates, being able to realize intelligent control of the warp yarn sizing process, and effectively reducing the cost of warp yarn sizing.

[0098] The above are only several embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the relevant art can make some changes or modifications within the scope of the technical solution of the present invention by using the disclosed technical content, which are all equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for online monitoring of sizing rate of sizing yarn, characterized in that: include: The textile pulp containing hydroxyl groups is modified to obtain a fluorescent identifiable pulp; The fluorescent identifiable size is used to size the warp yarn to obtain the sized yarn; The theoretical fluorescence intensity of the sized yarn under ultraviolet light irradiation is obtained, and the theoretical sizing rate of the sized yarn is determined according to the theoretical fluorescence intensity.

2. The method for online monitoring of sizing rate of sizing yarn according to claim 1, characterized in that: Modification of hydroxyl-containing textile pulp, specifically including: Introducing 1,4-dihydropyridine ring into hydroxyl-containing textile pulp.

3. The method for online monitoring of sizing rate of sizing yarn according to claim 2, characterized in that: Introducing 1,4-dihydropyridine ring into hydroxyl-containing textile pulp specifically includes: Esterifying the hydroxyl-containing textile pulp to obtain an esterified pulp; An aldehyde compound and an ammonium compound are added to the esterification slurry to cause the esterification slurry to undergo a Hantzsch reaction, thereby introducing a 1,4-dihydropyridine ring.

4. The method for online monitoring of sizing rate of sizing yarn according to claim 1, characterized in that: Determining the theoretical sizing rate of the sizing yarn according to the theoretical fluorescence intensity specifically includes: By using experimental methods, the mathematical relationship between the fluorescence intensity and the sizing rate of the sizing yarn is predetermined; Substituting the theoretical fluorescence intensity into the mathematical relationship, the theoretical sizing ratio of the sizing yarn is obtained.

5. The method for online monitoring of sizing rate of sizing yarn according to claim 4, characterized in that: The mathematical relationship between the fluorescence intensity and the sizing rate of the sizing yarn is predetermined by experimental methods, including: Sizing a plurality of experimental warp yarns using the fluorescent identifiable size of different concentrations to obtain a plurality of experimental sized yarns; Determining the sizing rate and fluorescence intensity of the plurality of experimental sized yarns; The fitting curve of the sizing rate and the fluorescence intensity is determined to obtain a mathematical relationship between the fluorescence intensity and the sizing rate of the sized yarn.

6. The method for online monitoring of sizing rate of sizing yarn according to claim 5, characterized in that: Determining the sizing rate and fluorescence intensity of the plurality of experimental sized yarns specifically includes: The sizing rate of each experimental sized yarn was determined by desizing method; Obtain the fluorescence intensity of each experimental sized yarn under ultraviolet light.

7. The method for online monitoring of sizing rate of sizing yarn according to claim 1, characterized in that: The concentration of the fluorescent molecules in the fluorescent identifiable slurry is 1% to 5%.

8. The method for online monitoring of sizing rate of sizing yarn according to claim 3, characterized in that: The aldehyde compound is at least one of dodecanal, formaldehyde, benzaldehyde, 4-hydroxybenzaldehyde, hexanal, and stearic aldehyde.

9. The method for online monitoring of sizing rate of sizing yarn according to claim 3, characterized in that: The ammonium compound is ammonium acetate.

10. The method for online monitoring of sizing rate of sizing yarn according to claim 3, characterized in that: Esterification of hydroxyl-containing textile pulp, including: adding an ester compound to a hydroxyl-containing textile pulp to esterify the hydroxyl-containing textile pulp; The ester compound is at least one of tert-butyl acetoacetate, ethyl acetoacetate and propyl acetoacetate.

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