A method for desizing of low-temperature and low-alkali long vehicle of nylon woven fabric

Abstract

The object of the present invention is to provide a low-temperature and low-alkali long-carriage desizing method for polyamide woven fabrics in view of the defects of the high-temperature and high-alkali long-carriage desizing process for polyamide woven fabrics. On the basis of a two-component desizing aid, the present invention further optimizes the desizing procedure, realizing the low-temperature and low-alkali long-carriage desizing of polyamide woven fabrics. The present invention solves the problems of high energy consumption, high pollution, and inhibition of the performance of auxiliaries brought about by the traditional high-temperature and high-alkali long-carriage desizing method for polyamide woven fabrics, bringing the development of the desizing process for chemical fiber woven fabrics to a new height in the future.

Description

Technical Field

[0001] The present invention belongs to the field of textile printing and dyeing, and relates to a method for continuous long vehicle desizing of polyamide woven fabric at low temperature and low alkali, which can achieve the desizing effect of high temperature and high alkali process under the conditions of low temperature and low alkali. Technical Background

[0002] Polyamide woven fabric has the characteristics of wear resistance, elasticity, high strength, etc., and is thus widely used in high-grade clothing fabrics, such as golf fabrics, down fabrics, ready-to-wear fabrics, etc. From polyamide woven grey fabric to the final finished fabric, a series of printing and dyeing processes are usually experienced, among which pretreatment is a VIP process because the quality of impurity removal determines the quality of subsequent processing. Since polyamide woven fabric itself does not contain natural impurities, the impurities on the fabric are mainly the sizing agents applied during the spinning and weaving processes and a little spinning oil agent. In view of this, the core work of polyamide woven fabric pretreatment is desizing. At present, polyamide woven fabric is generally processed by two processes: batch machine cylinder desizing and continuous long vehicle desizing. Among them, the latter has gradually become the mainstream desizing process in dyeing factories because of its sufficient desizing and high efficiency.

[0003] The sizing agent type of polyamide woven fabric is mainly polyacrylate, which mainly improves water solubility through alkali hydrolysis reaction to achieve the desizing effect. In actual production, in order to ensure complete desizing in a short time, the long vehicle desizing in dyeing factories usually adopts a high temperature and high alkali process (as shown in Figure 1 ), that is, a large amount of high temperature alkali liquor is used to increase the reaction rate of polyacrylate sizing agent. With the development of society, the problems of this high temperature and high alkali desizing process begin to emerge. Specifically, there are the following three points:

[0004] First, high energy consumption. Affected by the market style in recent years, dyeing factories are processing more and more high-count and high-density polyamide woven fabrics. Such fabrics have a large amount of sizing due to the fine and dense warp and weft yarns on the fabric surface, and are difficult to desize due to the large number of yarn filaments. Therefore, different from the polyacrylate sizing on other fabrics, the polyacrylate sizing wrapped on polyamide yarns has stronger flexibility, that is, more hydrophobic groups, so that the alkali liquor wets, penetrates and hydrolyzes the sizing slowly. In order to complete the desizing work, dyeing factories usually increase the desizing temperature (95 - 97 °C). This not only enhances the permeability of the auxiliary agent, facilitates the swelling of the sizing by the alkali liquor, but also increases the hydrolysis reaction rate of the sizing. However, it should be noted that high temperature often means high steam consumption and high energy consumption, which is contrary to the goal of the current annual decrease in energy consumption of printing and dyeing factories.

[0005] Second, serious pollution. Another measure taken by dyeing factories to improve the hydrolysis efficiency of polyacrylic acid sizing agents is to increase the dosage of alkali (30 - 100 g / L). After entering the new century, with the increasingly prominent environmental problems, the environmental protection pressure faced by the textile industry has become greater and greater, especially regarding the wastewater treatment problem in the wet processing of the textile industry. During the long vehicle desizing process of nylon woven fabric, a large amount of acid is required to neutralize the high-alkali wastewater, and even after such treatment, the salt content of the wastewater is still relatively high. On the other hand, the salting-out effect of high-concentration alkali will cause the polyacrylic acid sizing agent to aggregate and redeposit on the fabric surface, resulting in dyeing defects. Therefore, dyeing factories have to solve this problem by increasing the replacement frequency of the working solution in the desizing tank, but this will increase the amount of wastewater in the dyeing factory. For this reason, the wastewater pollution caused by the high-alkali desizing process has always been the most troublesome problem for dyeing factories.

[0006] Third, the high-temperature and high-alkali process limits the functionality of auxiliaries. As is well known, the long vehicle desizing process is also responsible for removing impurities such as spinning oil agents. Therefore, desizing auxiliaries are added during the desizing process to achieve the effect of impurity removal by utilizing the wetting, penetration, emulsification, and scouring functions of the desizing auxiliaries. However, in the extreme environment of high temperature and high alkali, the performance of most desizing auxiliaries will become inactivated. This phenomenon not only increases the limitations of the use of auxiliaries but also increases the dosage of auxiliaries during the processing, resulting in an increase in the comprehensive costs such as printing and dyeing processing fees and waste liquid treatment fees.

[0007] Although some patents such as CN105002759A and CN101476249B disclose various high-temperature and low-alkali chemical fiber desizing agents and their preparation methods, most of them are used in the same bath for desizing and dyeing, which not only does not meet the requirements of modern printing and dyeing but also cannot achieve the requirements of low-temperature desizing. Therefore, in order to solve the problems faced by the high-temperature and high-alkali long vehicle desizing process of nylon woven fabric, it is urgently necessary to develop a new continuous desizing process for nylon woven fabrics at the present stage. Summary of the Invention

[0008] The purpose of the present invention is to provide a two-component desizing auxiliary for the defects of the high-temperature and high-alkali long vehicle desizing process of nylon woven fabric. On the basis of the two-component desizing auxiliary, the present invention further optimizes the desizing procedure to achieve low-temperature and low-alkali long vehicle desizing of nylon woven fabric.

[0009] As one aspect of the present invention, the present invention innovatively designs a two-component low-temperature and low-alkali desizing assistant formed by combining two components, ensuring the smooth implementation of the above process. Among them, the novel component A significantly improves the permeability of the alkaline working solution; through the novel alkaline assistant B, the nylon fiber is "treated" to facilitate the better adsorption and penetration of the working solution on the nylon fabric. At the same time, the alkalinity of the assistant itself is used to reduce the dosage of the added alkali and the reaction temperature; more importantly, through the intermolecular hydrogen bond interaction between component A and B, it is ensured that phase separation does not occur between the two in the working solution, thus synergistically improving the reaction rate of the working solution to the sizing agent on the nylon woven fabric (especially high-count and high-density fabrics). It should be noted that the main components of component A and assistant B, namely the ultrafast penetrant and polyethyleneimine sulfonate, are synthesized and applied in the printing and dyeing field for the first time.

[0010] Specifically, the technical solution provided by the present invention is: a two-component desizing assistant, which includes component A and component B, and the mass ratio of component A to component B is 0.2-1:1;

[0011] Component A is composed of the following:

[0012] 20-60 parts by mass of ultrafast penetrant;

[0013] 10-20 parts by mass of secondary alcohol polyoxyethylene ether;

[0014] 30-60 parts by mass of deionized water;

[0015] In the present invention, the ultrafast penetrant is prepared by the following method: First, 196 parts by mass of sodium 3-chloro-2-hydroxypropanesulfonate and 177 parts by mass of isomeric acid are added to an esterification reaction kettle, and then a heteropolyacid is added as a catalyst. The temperature is heated to 165-170 °C, and the by-product water is continuously separated during the reaction. After the reaction is completed, the temperature is lowered to 70-80 °C for neutralization; then an ethanol solution of primary amine is added, and stirring is continued for 2-3 hours. After the reaction is completed, ethanol is removed to obtain the product. The structural general formula is as follows:

[0016]

[0017] In the formula, a is 1-4;

[0018] In the present invention, the primary amine is one or any combination of the following compounds: ethylamine, n-butylamine, isobutylamine, hexylamine, octylamine, decylamine, etc.; the molar ratio of its dosage to sodium 3-chloro-2-hydroxypropanesulfonate is 0.5-0.6:1.

[0019] Component B is composed of the following:

[0020]

[0021] In the present invention, the polyethyleneimine sulfonate is prepared by the following method: An aqueous solution of sodium 3-chloro-2-hydroxypropanesulfonate composed of 330 parts by mass of water and 393 parts of sodium 3-chloro-2-hydroxypropanesulfonate is added to 20 - 100 parts by mass of a 30% aqueous solution of polyethyleneimine, stirred at 70 - 80 °C for 2 hours, and then neutralized with 100 parts by mass of sodium hydroxide to obtain the product. The structural general formula is as follows:

[0022]

[0023] In the formula, b is 7 - 16.

[0024] In the present invention, by introducing an ultrafast penetrant with a special structural design into Component A, on the one hand, due to its symmetric disulfonate structure, it has outstanding wetting performance and persistent rewetting performance, and its performance is superior to that of penetrant T. On the other hand, the ester groups and comb-shaped hydrophobic alkyl groups in the molecular structure can, driven by hydrogen bonds and van der Waals forces, improve its affinity for fibers and polyacrylate sizing agents, increase the penetration radiation area, so as to quickly carry more lye on the surface of nylon fibers, give full play to the contact between the lye and the sizing agent, and improve the hydrolysis rate of the sizing agent. Considering that the sizing agent on the fabric surface may affect the functionality of the ultrafast penetrant, the present invention introduces secondary alcohol polyoxyethylene ether into Component A to improve the emulsification of Component A for the sizing agent and reduce the influence of the sizing agent on the penetrant.

[0025] In the present invention, by introducing polyethyleneimine sulfonate with a special structural design into Formula B, using the amino groups and imino groups in its structure, the binding property between it and the fibers can be increased, and under the electrostatic repulsion and steric hindrance effects of its multi-branched anionic polymer structure, the repulsion force between the fibers is increased, achieving an effect similar to "fiber opening", and greatly improving the permeability of the auxiliary agent. Potassium hydroxide is introduced as an alkali agent, and its high water solubility and alkalinity (relative to sodium hydroxide) effectively increase the utilization rate of hydroxide ions, avoiding the waste phenomenon of excessive lye in the high-alkali process. And potassium nitrilotriacetate plays a dual role in Formula B: it can both utilize its buffering property to continuously provide alkalinity for the system; at the same time, it can also chelate polyvalent metal ions (such as Ca 2+ , Mg 2+ , Fe 3+ etc.) brought in by the grey fabric to avoid the aggregation phenomenon of polyacrylate sizing agents induced by them.

[0026] In the present invention, for high-count and high-density nylon woven fabric with a count above 400T, the mass ratio of Component A to Component B is below 0.5:1.

[0027] As another aspect of the present invention, the present invention addresses the problem that the hydrolysis efficiency of sizing agents for nylon woven fabrics in traditional long vehicle desizing processes and supporting sizing agents is low (only high temperature and high alkali can improve the efficiency), and proposes a targeted solution strategy. Specifically, in the new process, the continuous desizing method adopts the strategy of short-time cold pad-batch and slow speed open-width desizing. That is, under the action of a two-component desizing agent, the polyacrylic acid sizing agent is rapidly hydrolyzed to shorten the relatively long cold pad-batch reaction time; in addition, although the open-width washing time is slightly extended, the shearing force during open-width can be fully utilized to ensure that the reacted polyacrylic acid sizing agent detaches from the fabric surface, achieving a perfect desizing effect. Since the overall open-width time is not long, the new process saves nearly 30% of the time compared to the traditional long vehicle desizing method with long-time cold pad-batch and relatively fast open-width (Table 1).

[0028] Specifically, the low-temperature and low-alkali long vehicle desizing method for nylon woven fabrics of the present invention comprises the following steps:

[0029] (1) Introduce the nylon woven grey fabric into a padding trough and pad it at 30 - 50°C. After padding, the liquor pickup rate of the nylon grey fabric is 20% - 60%; the padding trough contains the solution of the aforementioned two-component desizing agent, and the concentration of the two-component desizing agent is 10 - 30 g / L;

[0030] (2) Cold pad-batch the padded nylon woven grey fabric for 12 - 60 hours;

[0031] (3) Low-temperature and low-alkali long vehicle desizing: Continuously desize the cold pad-batched fabric in the desizing trough of the long vehicle equipment at 60 - 80°C; the desizing trough of the long vehicle equipment contains the desizing agent solution, the alkali in the desizing agent solution is NaOH, and the concentration of NaOH is below 10 g / L; the desizing agent can adopt existing ones such as TF-127H, DM-1320, etc., but is not limited thereto, and its concentration is 1 - 5 g / L.

[0032] In the present invention, for high-count and high-density nylon shuttle fabrics with a count above 400T and a denier below 30D, the cold pad-batch time should be not less than 48 hours.

[0033] In the present invention, the processing speed in step (3) is below 50 m / min.

[0034] In certain specific embodiments of the present invention, the following continuous desizing process is adopted:

[0035] S1: Prepare the two-component desizing agent, introduce the nylon woven grey fabric into the padding trough for padding and winding, ensuring that the nylon grey fabric absorbs an appropriate amount of the two-component desizing agent; wherein, the total amount of the sizing agents in the two-component desizing agent is 10 - 30 g / L, and no alkali needs to be added; pad at 30 - 50°C to ensure that the liquor pickup rate of the nylon grey fabric is 20% - 60%;

[0036] S2: Place the coiled fabric at room temperature and conduct cold pad-batch for different durations to ensure sufficient pre-swelling and hydrolysis of the sizing agent on the polyamide woven fabric. The cold pad-batch duration is 12 - 60 hours. For high-count and high-density polyamide shuttle-woven fabrics with a count above 400T and a denier below 30D, the cold pad-batch duration should be no less than 48 hours.

[0037] S3: Configure a working solution containing low-concentration alkali and traditional desizing auxiliaries in the desizing trough of the stentering equipment. Under low-temperature conditions, conduct continuous desizing on the grey fabric after cold pad-batch, continuously hydrolyze and wash the sizing agent. Subsequently, the desized fabric undergoes continuous water washing in a water washing trough with stepwise temperature reduction to wash the residual alkali and redeposited impurities on the fabric surface and complete the entire process. Among them, the alkali in the desizing auxiliary solution is NaOH, and the concentration of NaOH is below 10 g / L. The desizing auxiliaries can use existing ones such as TF-127H, DM-1320, etc., but are not limited to these, and their concentration is 1 - 5 g / L. And the working solution needs to be continuously replenished. The temperature of stentering desizing is 60 - 80°C, and the processing speed is below 50 m / min.

[0038] Due to the application of the above technical solutions, the present invention has the following advantages:

[0039] (1) Utilizing the excellent permeability of the above-mentioned auxiliary combination, the present invention optimizes the stentering desizing method for polyamide woven fabrics, that is, the hydrolysis process of the sizing agent is completed within a shorter cold pad-batch time, and there is no need for secondary desizing during the stentering flat-width process. This method can significantly reduce the concentration of alkali and processing temperature during cold pad-batch and flat-width processes, and shorten the overall processing time, truly achieving the effects of environmental protection, energy conservation, and time saving.

[0040] (2) Compared with the traditional high-temperature and high-alkali process, the above low-temperature and low-alkali stentering desizing method has mild conditions and fully exerts the net washing effect of the auxiliaries, enabling the whiteness of the fabric after desizing to be significantly improved.

[0041] (3) The traditional desizing agent itself contains phosphorus compounds, so the related desizing wastewater causes relatively large environmental pollution. The auxiliary formulation in the low-temperature and low-alkali desizing process of the present invention is phosphorus-free, non-toxic, and pollution-free, meeting the environmental protection requirements of the market for textile auxiliaries. Description of the Drawings

[0042] Figure 1 Curve diagrams of the conventional high-temperature and high-alkali desizing process and the low-temperature and low-alkali process in the specific implementation manner of the present invention;

[0043] Figure 2Desizing effects (after cationic dye coloring) under the desizing processes of Examples 1-4 (corresponding to a-d respectively) and Comparative Examples 1-3 (e-f). The cationic coloring method mainly relies on the cationic GRL red dye to color the negatively charged polyacrylic acid sizing agent on the fiber surface. Therefore, the redder the fabric surface color, the more polyacrylic acid sizing agent remains. From the results in the figure, it can be seen that the desizing effects of Examples 1-4 (a-d) can reach the desizing effect of the high-alkali desizing in Comparative Example (g). At the same time, it can also be seen that the auxiliary agent combination must be used in a matching manner to achieve the desizing effect. Detailed implementation manners

[0044] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will, in conjunction with the accompanying drawings and preferred embodiments, describe in detail the specific implementation manners, structures, features and their effects of the present invention as follows.

[0045] Synthesis Example 1: Synthesis of an ultra-fast penetrant

[0046] First, 196 parts by mass (1 molar amount) of sodium 3-chloro-2-hydroxypropanesulfonate and 225 parts by mass (1.05 molar amount, calculated according to a = 4) of isomeric acid are added to an esterification reaction kettle, and then phosphotungstic heteropolyacid is added as a catalyst. The mixture is heated to 165-170 °C, and by-products water is continuously separated during the reaction. After the reaction ends, the temperature is lowered to 70-80 °C for neutralization; subsequently, an ethanol solution containing 27 parts by mass (0.6 molar amount) of ethylamine is added, and stirring is continued for 2-3 hours. After the reaction ends, ethanol is removed to obtain the product, and its structural formula is as follows:

[0047]

[0048] Synthesis Example 2: Synthesis of an ultra-fast penetrant

[0049] First, 196 parts by mass of sodium 3-chloro-2-hydroxypropanesulfonate and 181 parts by mass of isomeric acid (1.05 molar amount, calculated according to a = 1) are added to an esterification reaction kettle, and then phosphotungstic heteropolyacid is added as a catalyst. The mixture is heated to 165-170 °C, and by-products water is continuously separated during the reaction. After the reaction ends, the temperature is lowered to 70-80 °C for neutralization; subsequently, an ethanol solution containing 36.5 parts by mass (0.5 molar amount) of butylamine is added, and stirring is continued for 2-3 hours. After the reaction ends, ethanol is removed to obtain the product, and its structural formula is as follows:

[0050]

[0051] Synthesis Example 3: Synthesis of polyethyleneimine sulfonate

[0052] An aqueous solution of sodium 3-chloro-2-hydroxypropanesulfonate composed of 330 parts by mass of water and 393 parts of sodium 3-chloro-2-hydroxypropanesulfonate was added to 20 parts by mass of an aqueous solution of polyethyleneimine with a mass fraction of 30%. Stir at 70 - 80 °C for 2 hours, and then neutralize with 100 parts by mass of sodium hydroxide to obtain Product 1.

[0053] Synthesis Example 4: Synthesis of Polyethyleneimine Sulfonate

[0054] An aqueous solution of sodium 3-chloro-2-hydroxypropanesulfonate composed of 330 parts by mass of water and 393 parts of sodium 3-chloro-2-hydroxypropanesulfonate was added to 100 parts by mass of an aqueous solution of polyethyleneimine with a mass fraction of 30%. Stir at 70 - 80 °C for 2 hours, and then neutralize with 100 parts by mass of sodium hydroxide to obtain Product 2.

[0055] The structural formulas of the products obtained in the above Synthesis Examples 3 - 4 are as follows:

[0056]

[0057] where b is 7 - 16.

[0058] Example 1: Low-temperature and low-alkali long vehicle desizing method for nylon woven fabric, including the following steps ( Figure 1 ):

[0059] S1: Prepare a working solution containing Component A and Component B. Introduce the nylon woven grey fabric (3000 m long) into the padding trough, pad and wind it in the working solution at 45 °C to ensure that the liquid pickup rate of the nylon grey fabric is 60%;

[0060] S2: Place the wound fabric at room temperature for cold stacking to ensure that the sizing agent on the nylon woven fabric undergoes sufficient pre-swelling and hydrolysis;

[0061] S3: Prepare a working solution containing 1.0 g / L of alkali (NaOH) and 3 g / L of TF-127H in the desizing trough of the long vehicle equipment. At 75 °C, continuously desize the fabric after cold stacking, with a processing speed of 30 m / min; continuously hydrolyze and wash the sizing agent; then the desized fabric undergoes continuous water washing in a water washing trough with gradually decreasing temperature to wash the residual alkali and redeposited impurities on the fabric surface, and end the entire process.

[0062] Component A and Component B, and the cold stacking time are shown in Table 1.

[0063] Example 2: Low-temperature and low-alkali long vehicle desizing method for nylon woven fabric, including the following steps ( Figure 1 ):

[0064] S1: Prepare a working solution containing Component A and Component B. Introduce the nylon woven grey fabric (3000 m in length) into the padding trough, pad and wind it in the working solution at 30 °C, ensuring that the liquor pickup rate of the nylon grey fabric is 20%;

[0065] S2: Place the wound fabric at room temperature for cold stacking to ensure that the sizing agent on the nylon woven fabric undergoes sufficient pre-swelling and hydrolysis;

[0066] S3: Prepare a working solution containing 10.0 g / L of alkali (NaOH) and 5 g / L of TF-127H in the desizing trough of the stentering machine. At 60 °C, continuously desize the fabric after cold stacking. The processing speed is 50 m / min to continuously hydrolyze and wash the sizing agent. Subsequently, the desized fabric undergoes continuous water washing in a water washing trough with gradually decreasing temperature to wash the residual alkali and redeposited impurities on the fabric surface, and the entire process ends.

[0067] Component A and Component B, and the cold stacking time are shown in Table 1.

[0068] Example 3: A method for low-temperature and low-alkali stentering desizing of nylon woven fabric, comprising the following steps ( Figure 1 ):

[0069] S1: Prepare a working solution containing Component A and Component B. Introduce the nylon woven grey fabric (3000 m in length) into the padding trough, pad and wind it in the working solution at 50 °C, ensuring that the liquor pickup rate of the nylon grey fabric is 30%;

[0070] S2: Place the wound fabric at room temperature for cold stacking to ensure that the sizing agent on the nylon woven fabric undergoes sufficient pre-swelling and hydrolysis;

[0071] S3: Prepare a working solution containing 8.0 g / L of alkali (NaOH) and 4 g / L of DM-1320 in the desizing trough of the stentering machine. At 80 °C, continuously desize the fabric after cold stacking. The processing speed is 20 m / min to continuously hydrolyze and wash the sizing agent. Subsequently, the desized fabric undergoes continuous water washing in a water washing trough with gradually decreasing temperature to wash the residual alkali and redeposited impurities on the fabric surface, and the entire process ends.

[0072] Component A and Component B, and the cold stacking time are shown in Table 1.

[0073] Example 4: A method for low-temperature and low-alkali stentering desizing of nylon woven fabric, comprising the following steps ( Figure 1 ):

[0074] S1: Prepare a working solution containing Component A and Component B. Introduce the nylon woven grey fabric (3000 m in length) into the padding trough, pad and wind it in the working solution at 20 °C, ensuring that the liquor pickup rate of the nylon grey fabric is 30%;

[0075] S2: Place the coiled fabric at room temperature for cold padding to ensure sufficient pre-swelling and hydrolysis of the sizing agent on the polyamide woven fabric.

[0076] S3: Configure a solution containing 6.0 g / L of alkali (NaOH) and 1 g / L of DM-1320 in the desizing tank of the stentering machine. At 60 °C, continuously desize the grey fabric after cold padding at a processing speed of 20 m / min to continuously hydrolyze and wash the sizing agent. Subsequently, the desized fabric undergoes continuous water washing in a water washing tank with a stepwise decreasing temperature to wash away the residual alkali and redeposited impurities on the fabric surface, and the entire process ends.

[0077] Components A and B, and the cold padding time are shown in Table 1.

[0078] Comparative Examples 1-2:

[0079] The difference from Example 2 is that Examples 5 and 6 are different in step S1. That is, when preparing the working solution, only one of the auxiliary agent combinations is added. For example, in Example 5, only Component A is added, and in Example 6, only Auxiliary Agent B is added. The remaining steps are the same as those in Example 2.

[0080] The specific process and formulation parameters of Examples 1-6 are shown in Table 1.

[0081] Table 1 Specific process and formulation parameters in the examples

[0082]

[0083] [1] The parameters of the Taslan fabric are 280T / 70D, the parameters of the Nylon Twill fabric are 430T / 20D, and the parameters of the Nylon-Spandex Four-Way Stretch (the ratio of nylon and spandex fibers in the warp and weft yarns of the fabric is 95%:5%) fabric are 360T / 40D.

[0084] Comparative Example 3: The traditional stentering desizing method for polyamide woven fabric, including the following steps ( Figure 1 ):

[0085] S1: Prepare a working solution containing the traditional desizing agent DM-1320 (5 g / L), chelating dispersant (10 g / L), and liquid alkali (150 g / L), and heat it to 55 °C. Subsequently, introduce 3000 m of 430T / 20D polyamide Nylon Twill grey fabric into the padding trough for padding and coiling, and replenish the liquid in real time;

[0086] S2: Place the coiled fabric impregnated with the working solution at room temperature for 72 h of cold padding;

[0087] S3: Configure a working solution containing 100 g / L of liquid caustic soda and 3 g / L of traditional desizing agent in the desizing tank of the long vehicle equipment. Under the conditions of 95 °C and 60 m / min, continuously desize the greige cloth after cold pad-batch; then the desized cloth undergoes continuous water washing in a water washing tank with a stepwise temperature reduction to clean the residual alkali and redeposited impurities on the cloth surface, and end the entire process.

[0088] Table 2 Whiteness values of nylon fabrics after desizing under the desizing processes of Examples 1-4 and Comparative Examples 1-3 (directly measured on the desized cloth).

[0089] Example Whiteness value Comparative example Whiteness value 1 85.20 1 73.32 2 82.62 2 70.43 3 85.02 3 75.33 4 81.15

[0090] From the results in Table 3 and Figure 2 it can be seen that the nylon fabrics processed by the low-temperature and low-alkali long vehicle desizing method have higher whiteness values, which are better than the traditional high-temperature and high-alkali process. Further combining with Table 2, it can be seen that the low-temperature and low-alkali long vehicle desizing process based on the two-component desizing agent of the present invention greatly saves the time of the desizing process on the premise of ensuring product quality.

[0091] Example 5

[0092] Using the same operation plan as in Example 2, desize different fabrics and compare with the high-temperature and high-alkali desizing process of Comparative Example 3, as shown in Table 3 specifically.

[0093] Table 3 Comparison between the process of the present invention and the traditional process

[0094]

[0095] The above is only a preferred embodiment of the present invention, and it does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the above-disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for desizing long truck of low temperature and low alkali for polyamide woven fabric, characterized in that, it comprises the following steps: (1) Introduce the polyamide woven grey fabric into the padding trough and pad it at 30 - 50 °C. After padding, the liquid pickup rate of the polyamide woven grey fabric is 20% - 60%; a solution of a two-component desizing aid is placed in the padding trough, and the concentration of the two-component desizing aid is 10 - 30 g / L; (2) Cold stack the padded polyamide woven grey fabric for 12 - 60 hours; (3) Desize with low temperature and low alkali long truck: Continuously desize the cold-stacked polyamide woven grey fabric in the desizing trough of the long truck equipment at 60 - 80 °C; a desizing aid solution is placed in the desizing trough of the long truck equipment, the alkali in the desizing aid solution is NaOH, and the concentration of NaOH is below 10 g / L; The two-component desizing aid in step (1) includes component A and component B, and the mass ratio of component A to component B is 0.2 - 1:1; wherein, Component A is composed of: 20 - 60 parts by mass of an ultra-fast penetrant; 10 - 20 parts by mass of secondary alcohol polyoxyethylene ether; 30 - 60 parts by mass of deionized water; The ultra-fast penetrant is prepared by the following method: First, add 196 parts by mass of 3-chloro-2-hydroxypropanesulfonic acid sodium salt and 177 parts by mass of isomeric acid into an esterification reaction kettle, then add a heteropolyacid as a catalyst, heat to 165 - 170 °C, continuously separate by-product water during the reaction, after the reaction ends, cool to 70 - 80 °C for neutralization; then add an ethanol solution of primary amine, continue to stir for 2 - 3 hours, and remove ethanol after the reaction ends to obtain the product, and its structural general formula is as follows: The primary amine is one or any combination of the following compounds: ethylamine, n-butylamine, isobutylamine, hexylamine, octylamine, decylamine; the molar ratio of the dosage of the primary amine to 3-chloro-2-hydroxypropanesulfonic acid sodium salt is 0.5 - 0.6:1; Component B is composed of: 20 - 50 parts by mass of polyethyleneimine sulfonate; 5 - 15 parts by mass of potassium hydroxide; 5 - 15 parts by mass of potassium nitrilotriacetate; 30 - 60 parts by mass of deionized water; The polyethyleneimine sulfonate is prepared by the following method: Add an aqueous solution of 3-chloro-2-hydroxypropanesulfonic acid sodium salt composed of 330 parts by mass of water and 393 parts by mass of 3-chloro-2-hydroxypropanesulfonic acid sodium salt into 20 - 100 parts by mass of a 30% polyethyleneimine aqueous solution, stir at 70 - 80 °C for 2 hours, and then neutralize with 100 parts by mass of sodium hydroxide to obtain the product, and its structural general formula is as follows: In the formula, b is 7 - 16.

2. The method for desizing long truck of low temperature and low alkali for polyamide woven fabric according to claim 1, characterized in that, The polyamide woven grey fabric uses a high-count and high-density polyamide shuttle fabric with more than 400T and below 30D, and its cold stack time is not less than 48 hours.

3. The method for desizing long truck of low temperature and low alkali for polyamide woven fabric according to claim 1, characterized in that, The processing speed in step (3) is lower than 50 m / min.

4. The method for desizing long truck of low temperature and low alkali for polyamide woven fabric according to claim 1, characterized in that, The polyamide woven grey fabric uses a high-count and high-density polyamide woven fabric with a count of over 400T. Among them, the mass ratio of component A to component B is below 0.5:1.

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