Cationic hydrophilic softener for chinlon dyeing one-bath and preparation method and application thereof

Abstract

The invention relates to a cationic hydrophilic softener for chinlon dyeing in one bath as well as a preparation method and application of the cationic hydrophilic softener. The method comprises the following steps: S1, carrying out hydrosilylation reaction on end hydrogen-containing silicone oil and allyl epoxy polyether under the action of a platinum catalyst; s2, polyol containing hydroxyl and polyisocyanate are subjected to a reaction under the action of a first catalyst, and a-NCO-terminated polyurethane prepolymer is generated; a chain extender containing a tertiary amine group is added into the polyurethane prepolymer for a reaction; adding the epoxy-terminated polyether silicone oil obtained in the step S1 for reaction, and then adding acid for neutralization to obtain cationic polyurethane modified silicone oil; and S3, emulsifying. The softening agent prepared by the invention has excellent stability in a high-temperature acid dye bath, and does not demulsify and stick to a vat; the compatibility with acid dyes is good, and color spots and color spots can be effectively avoided; and after use, the chinlon fabric can be endowed with lasting, smooth and soft hand feeling and good hydrophilicity, and meanwhile, the original whiteness of the fabric is kept.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of textile chemicals, and relates to a cationic hydrophilic softener for nylon dyeing in a one-bath process as well as a preparation method and application thereof. BACKGROUND

[0002] Nylon (polyamide fiber) is widely used in clothing, home textiles and industrial fields due to its excellent strength, wear resistance and elasticity. In the finishing process of nylon fabric, soft finishing is a key link to improve the hand feeling, comfort and added value of products. The traditional dyeing and finishing process generally adopts a two-step processing mode of “dyeing first and softening later”, that is, the fabric is first dyed in an acid dye bath, and then washed and drained before being treated in a new softening bath. This mode has a long process flow, and the fabric needs to be repeatedly washed and dried, which not only significantly increases the production time, but also leads to huge energy consumption of water, electricity and steam.

[0003] To meet the green and efficient development needs of the textile industry, the one-bath one-step dyeing and softening technology has emerged as the times require. This technology aims to add softener directly to the dye bath after dyeing, and use the residual heat and equipment of dyeing to realize soft finishing, thereby eliminating the intermediate washing, draining and heating processes, greatly shortening the process flow and significantly reducing energy consumption, water consumption and wastewater discharge.

[0004] However, the one-bath process puts extremely strict requirements on the performance of softeners. Nylon is usually dyed with acid dyes at high temperature (about 90-100℃) and in an acidic environment (pH 4-5), and the dye bath also contains various anionic auxiliaries. Traditional silicone softeners, especially weakly cationic products, have problems in this environment: 1) poor stability: under acidic and high-temperature conditions, the amino groups on the softener molecules are protonated, the electrical properties are enhanced, and they are easily neutralized with anionic dyes and auxiliaries in the dye bath, leading to emulsion breaking and oiling of the softener, commonly known as “cylinder staining” and “roller staining”, which pollutes the equipment and affects production; 2) poor compatibility: cationic softeners are prone to flocculation and precipitation with anionic dye molecules, forming color spots and color flowers on the fabric surface, which seriously affects the dyeing quality.

[0005] Therefore, developing a new type of softener that can maintain high stability in a high-temperature acidic dye bath, has good compatibility with anionic dye systems, and at the same time imparts excellent softness to the fabric without affecting or even improving the color and color fastness of the fabric, and also has hydrophilicity, is a technical problem that needs to be solved for the industrial application of nylon dyeing and finishing in a one-bath process. SUMMARY

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a cationic hydrophilic softener for dyeing nylon in the same bath. This softener aims to solve the problems of poor stability and poor compatibility with anionic dyes in traditional softeners in the dyeing process.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A method for preparing a cationic hydrophilic softener for dyeing nylon in the same bath, the method comprising the following steps:

[0009] S1 Preparation of terminal epoxy polyether silicone oil: Hydrosilylation reaction of terminal hydrogen-containing silicone oil with allyl epoxy polyether is carried out in the presence of platinum catalyst to obtain terminal epoxy polyether silicone oil.

[0010] S2 Preparation of Cationic Polyurethane Modified Silicone Oil:

[0011] A polyol containing hydroxyl groups is reacted with a polyisocyanate under the action of a first catalyst to generate a -NCO-terminated polyurethane prepolymer.

[0012] A chain extender containing tertiary amine groups is added to the polyurethane prepolymer for reaction; terminal epoxy polyether silicone oil obtained from S1 is added for reaction, followed by neutralization with acid to obtain cationic polyurethane modified silicone oil;

[0013] The total molar ratio n(-NCO):n(-OH) of the -NCO group in the polyisocyanate to the -OH group in the hydroxyl-containing polyol and the tertiary amine-containing chain extender is 0.2:1 to 1:1;

[0014] S3 Emulsification: The cationic polyurethane modified silicone oil obtained in S2 is mixed with an emulsifier and water is added for emulsification to obtain the cationic hydrophilic softener for nylon dyeing bath.

[0015] The softener prepared by this invention exhibits excellent stability in high-temperature acidic dyeing baths, without emulsion breakage or staining; it has good compatibility with acidic dyes, effectively preventing the formation of color spots and discoloration; after use, it imparts a lasting, smooth, soft feel and good hydrophilicity to nylon fabrics, while maintaining the original whiteness of the fabric, and has a positive impact on dyeing depth (K / S value) and color fastness.

[0016] Preferably, in step S1, the molar ratio of Si-H groups in the hydrogen-terminated silicone oil to C=C double bonds in the allyl epoxy polyether is 1:1.0-1.1. This molar ratio ensures complete reaction of the hydrogen-terminated silicone oil, resulting in a well-defined terminal epoxy polyether silicone oil. More preferably, the molar ratio of Si-H groups in the hydrogen-terminated silicone oil to C=C double bonds in the allyl epoxy polyether is 1:1.01.

[0017] Preferably, in S2, the polyol containing hydroxyl groups is polypropylene glycol, the polyisocyanate is isoflurane diisocyanate, and the chain extender containing tertiary amine groups is triethanolamine.

[0018] Preferably, the total molar ratio (n(-NCO):n(-OH)) of the -NCO groups in the polyisocyanate to the -OH groups in the hydroxyl-containing polyol and the tertiary amine-containing chain extender is 0.6:1. Under this condition, the application properties such as softness and K / S value are improved most effectively.

[0019] Preferably, in step S2, the amount of the terminal epoxy polyether silicone oil is 10% to 50% of the total mass of the reactants in S2. This content range balances the product's softness and emulsion stability. To obtain optimal emulsion stability (i.e., small and uniformly distributed emulsion particle size), the amount of the terminal epoxy polyether silicone oil is particularly preferably 20% to 30% of the total mass of the reactants in S2.

[0020] Preferably, the specific operating conditions for S2 are as follows: at 40-50°C, the polypropylene glycol and the isoflurane diisocyanate are reacted in the presence of dibutyltin dilaurate catalyst for 30-90 minutes to generate the -NCO-terminated polyurethane prepolymer; then the triethanolamine is added, and the temperature is raised to 80°C and kept at that temperature for 1-4 hours; the temperature is lowered to 40°C, and acetic acid is added for neutralization.

[0021] Preferably, the molar ratio of polypropylene glycol to isoflurone diisocyanate is 1:2;

[0022] The primary catalyst is dibutyltin dilaurate (DBTDL), and the amount of dibutyltin dilaurate used accounts for 0.5% of the total mass of the reactants.

[0023] The molar ratio of triethanolamine to isoflurane diisocyanate is 1.05:1;

[0024] The molar ratio of triethanolamine to acetic acid is 1:1. Preferably, in S3, the mass ratio of cationic polyurethane modified silicone oil to emulsifier (such as isomeric alcohol XL-50) is 1:0.25.

[0025] Preferably, the temperature of the hydrosilylation reaction in S1 is 70℃ ~ 80℃, and the reaction time is 2 ~ 3 hours.

[0026] Preferably, in S1, the hydrosilylation reaction system contains an appropriate amount of solvent, and the amount of solvent accounts for 30% to 45% of the total mass of the system.

[0027] Preferably, the molecular weight of the hydrogen-terminated silicone oil in S1 is 8000 g / mol, and the molecular weight of the allyl epoxy polyether is 500 g / mol.

[0028] This invention also protects a cationic hydrophilic softener for nylon dyeing in the same bath, prepared by any of the above preparation methods. This softener is essentially an oil-in-water emulsion containing the core cationic polyurethane-modified organosilicon compound of this invention, an emulsifier, and water. The structure of the cationic polyurethane-modified organosilicon compound comprises:

[0029] The polysiloxane backbone is polymerized from hydrogen-terminated silicone oil;

[0030] The cationic polyurethane segments formed by the reaction of polypropylene glycol, isoflurone diisocyanate and triethanolamine are grafted onto the ends of the polysiloxane backbone via hydrosilylation reaction.

[0031] The cationic polyurethane segment contains a tertiary amine group that is neutralized by acid and carries a positive charge.

[0032] Preferably, the emulsion has an average particle size of 90-250 nm, which ensures the storage stability and dispersibility of the emulsion in the working solution.

[0033] The present invention discloses the use of a cationic hydrophilic softener for dyeing nylon fabrics in a dyeing bath, comprising adding the softener directly to the dye bath after the acid dyeing step without changing the dye bath for softening finishing.

[0034] The specific implementation method of this application is as follows: after the step of dyeing nylon fabric with acidic dye is completed, without changing or discharging the dye bath, the softener is directly added to this high-temperature acidic dye bath for softening and finishing. Then, the fabric is dried, soaped and other subsequent treatments to obtain a hydrophilic fabric with both excellent color and soft hand feel.

[0035] The beneficial effects of this invention are:

[0036] 1. This invention combines hydrophilic polyurethane segments with hydrophobic polysiloxane segments via chemical bonds to form a structurally stable block copolymer. This copolymer provides softness, adhesion, and permeability, avoiding the phase separation risks associated with traditional physical blends. Its polysiloxane structure allows it to form a thin film on the fabric surface, reducing frictional resistance between fibers and imparting a soft, smooth feel to the fabric. Compared to traditional physically blended softeners, the softener of this invention reduces the risk of phase separation and demulsification in high-temperature, acidic, and high-shear dyeing environments, exhibiting excellent process stability.

[0037] 2. This invention introduces the tertiary amine group of triethanolamine as a cationic center, which is protonated in the acidic environment of the dye bath (pH 4-5), exhibiting weak cationic properties. This electrical property allows it to react with the sulfonate group (-SO₄) of the anionic dye already applied to the fiber. 3-It generates electrostatic attraction, thereby adsorbing onto the fiber surface in a directional manner and improving color fastness, rather than flocculating with free dye molecules in the dye bath, thus solving the defects of "color spots and color variations" in the same bath process.

[0038] 3. Polysiloxane segments impart excellent softness and smoothness to the fabric; polyurethane segments provide good film-forming properties and adhesion; and the polyether structure and tertiary amine groups ensure excellent hydrophilicity after fabric finishing. Simultaneously, due to the orderly adsorption of softeners on the fiber surface, the apparent dyeing depth (K / S value) and rubbing fastness of the fabric can be improved to a certain extent.

[0039] 4. The product of this invention can be directly used for dyeing and finishing in the same bath, realizing dyeing and softening in one step, shortening the production cycle, saving a lot of water, electricity, steam and other resources, reducing wastewater discharge, and meeting the requirements of green and sustainable development in the textile industry. Attached Figure Description

[0040] Figure 1 It is a blank sample of nylon fabric that has only been dyed and has not undergone softening treatment in the same bath;

[0041] Figure 2 It is the nylon fabric after dyeing and softening treatment in Example 6; Detailed Implementation

[0042] The technical solution of the present invention will be further described in detail below through specific embodiments. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any modifications and / or alterations made to the present invention will fall within the protection scope of the present invention.

[0043] In this invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used are commercially available or commonly used in the art. Unless otherwise specified, the methods in the following embodiments are conventional methods in the art.

[0044] Unless otherwise specified, the reagents used in the following examples can be purchased from a regular biochemical reagent store.

[0045] Hydrogen-containing silicone oil with a molecular weight of 8000 g / mol was purchased from Tongxiang Dingjun Textile Technology Co., Ltd.

[0046] Emulsifier isomeric alcohol XL-50 was purchased from Guangzhou Changhong Chemical Co., Ltd.

[0047] Test methods for hydrophilicity, softness, whiteness, and K / S ratio:

[0048] 1. Determination of the hydrophilic properties of fabrics

[0049] The water droplet diffusion time of nylon fabric was tested in accordance with the test standard "Evaluation of the moisture absorption and quick-drying properties of textiles - Part 1: Single combination test method" (GBT 21655.1-2023).

[0050] 2. Fabric softness

[0051] The stiffness, softness, and smoothness of cotton fabrics are tested using a smart style meter.

[0052] 3. Fabric whiteness

[0053] Using fabric whiteness to characterize its performance is one of the most important methods. Following the standard GB / T17644-2008, a smart whiteness tester was used to test the whiteness of silk fabrics treated with finishing agents, and the whiteness values ​​were recorded. The whiteness values ​​of untreated silk fabrics were also tested for comparison.

[0054] 4. K / S of the fabric

[0055] The K / S value was tested using a Datacolor SF 600X colorimeter with a D65 light source and an ultra-small aperture. Three parallel measurements were taken, and the average value was calculated.

[0056] Example 1

[0057] A method for preparing a cationic hydrophilic softener for dyeing nylon in the same bath, the specific steps of which are as follows:

[0058] (1) Preparation of epoxy polyether silicone oil

[0059] 20g of hydrogen-terminated silicone oil, 2.5g of allyl epoxy polyether and 18g of solvent isopropanol were mixed, heated to 75°C, and 149ul of catalyst chloroplatinic acid was added. The reaction was carried out for 2 hours to synthesize intermediate hydrogen-terminated epoxy polyether silicone oil.

[0060] The molar ratio (n(Si-H): n(C=C)) of Si-H in the hydrogen-containing silicone oil and C=C in the allyl epoxy polyether is 1:1.01.

[0061] (2) Preparation of cationic polyurethane modified silicone oil

[0062] 2.67 g of isoflurane diisocyanate (IPDI) and 14.00 g of polypropylene glycol (PPG-1000) were vacuum dehydrated and mixed thoroughly. One drop of dibutyltin dilaurate (DBTDL) was added, and the mixture was heated to 40 °C and reacted for 30 min. The temperature was then increased to 45 °C, and 0.6 g of triethanolamine was added. The viscosity was adjusted with acetone, and the reaction was maintained at this temperature for 80 min. A polyurethane prepolymer was obtained. 6.04 g of terminal epoxy polyether silicone oil was added, and the mixture was heated to 80 °C and maintained for 4 h. The temperature was then lowered to 40 °C, neutralized with acetic acid for one hour, and then cooled to room temperature. A cationic polyurethane-modified silicone oil was obtained.

[0063] In this embodiment, the molar ratio of Si-H in the hydrogen-terminated silicone oil to C=C in the allyl epoxy polyether (n(Si-H): n(C=C)) is 1:1.01, the molar ratio of isoflurane diisocyanate to polypropylene glycol and triethanolamine (n(-NCO): n(-OH)) is 0.6:1, and the mass of the epoxy polyether silicone oil accounts for 35% of the added reactants.

[0064] Example 2

[0065] Compared to Example 1, the following changes were made: "2.67g isoflurone diisocyanate" in step (2) was changed to "3.56g isoflurone diisocyanate"; the rest was the same as in Example 1.

[0066] Example 3

[0067] Compared to Example 1, the following changes were made: "2.67g isoflurane diisocyanate" in step (2) was changed to "1.78g isoflurane diisocyanate"; the rest was the same as in Example 1.

[0068] Example 4

[0069] Compared to Example 1, the following changes were made: "2.67g isoflurane diisocyanate" in step (2) was changed to "0.89g isoflurane diisocyanate"; the rest was the same as in Example 1.

[0070] Example 5

[0071] Compared to Example 1, the following changes were made: "2.67g isoflurane diisocyanate" in step (2) was changed to "4.45g isoflurane diisocyanate"; the rest was the same as in Example 1.

[0072] Examples 1-5 investigated the effect of the molar ratio (n(-NCO):n(-OH)) of isoflurane diisocyanate to polypropylene glycol and triethanolamine on the stability of the emulsion. The results are shown in Table 1.

[0073] Table 1. Effects of emulsion appearance and the molar ratio of triethanolamine and polypropylene glycol to isoflurone diisocyanate (n(-NCO):n(-OH)) on emulsion stability.

[0074]

[0075] As shown in Table 1, with the increase of n(-NCO):n(-OH), the emulsion particle size increases, the particle size distribution increases, and the stability decreases. The increase in n(-NCO):n(-OH) leads to severe microphase separation between the silicone and polyurethane, resulting in decreased emulsion stability. Furthermore, the combined effect of the hard segments and silicone increases the hydrophobicity of the system, requiring more emulsifier to stabilize into small particles. While increasing n(-NCO):n(-OH) improves coating film formation, exceeding a certain ratio leads to dye adhesion and severe color spots. Considering all factors, an n(-NCO):n(-OH) ratio of 0.6:1 was chosen.

[0076] Example 6

[0077] Compared to Example 1, the following changes were made: in step (2), “6.04g of terminal epoxy polyether silicone oil” was changed to “5.19g of terminal epoxy polyether silicone oil”; the rest were the same as in Example 1.

[0078] Example 7

[0079] Compared to Example 1, the following changes were made: in step (2), “6.04g of terminal epoxy polyether silicone oil” was changed to “1.73g of terminal epoxy polyether silicone oil”; the rest were the same as in Example 1.

[0080] Example 8

[0081] Compared to Example 1, the following changes were made: in step (2), “6.04g of terminal epoxy polyether silicone oil” was changed to “3.45g of terminal epoxy polyether silicone oil”; the rest were the same as in Example 1.

[0082] Example 9

[0083] Compared to Example 1, the following changes were made: in step (2), “6.04g of terminal epoxy polyether silicone oil” was changed to “6.91g of terminal epoxy polyether silicone oil”; the rest was the same as in Example 1.

[0084] Example 10

[0085] Compared to Example 1, the following changes are made: in step (2), “6.04g of terminal epoxy polyether silicone oil” is changed to “8.64g of terminal epoxy polyether silicone oil”, and the rest is the same as in Example 1.

[0086] Examples 6-10 investigated the effect of the mass percentage of end-epoxy polyether silicone oil (as a percentage of the reactant system) on the emulsion stability. The results are shown in Table 2.

[0087] Table 2. Effect of emulsion appearance and mass percentage of terminal epoxy polyether silicone oil (as a percentage of the reactant system) on emulsion stability.

[0088]

[0089] As shown in Table 2, the emulsion performance test results indicate that with increasing w(EPSI), the emulsion particle size and particle size distribution increase, while the stability decreases. With increasing w(EPSI) and silicone oil content, severe microphase separation between polyurethane and silicone oil occurs. Considering all factors, a w(EPSI) content of 20%–30% is selected.

[0090] Example 11

[0091] Pour the emulsified hydrophilic functional softener into centrifuge tubes and place them in a benchtop high-speed centrifuge. Centrifuge at 3000 r / min for 30 min and then observe the state of the emulsion.

[0092] Examples 6-8 of this invention successfully prepared uniform, milky-white cationic hydrophilic softener emulsions using the described preparation method, with average particle sizes ranging from 90-250 nm. This demonstrates that the present invention chemically grafts hydrophilic polyurethane segments with hydrophobic polysiloxane segments to form structurally stable block copolymers. In centrifugal stability tests, the emulsions of Examples 6-8 showed no stratification or demulsification, exhibiting extremely high product stability.

[0093] In contrast, the emulsions of Comparative Example 1 (traditional amino silicone oil) and Comparative Example 2 (physical blend) were cloudy in appearance, had excessively large particle sizes, and exhibited severe stratification in stability tests, indicating that they could not form a stable and homogeneous emulsion system. Therefore, the preparation method of "first synthesizing a polyurethane prepolymer, then grafting terminal epoxy polyether silicone oil" adopted in this invention is the key to obtaining a highly stable softener emulsion, solving the technical problem of poor stability in traditional products and simple physical blends.

[0094] To investigate the application of the cationic hydrophilic softener prepared in this invention for dyeing and finishing nylon fabrics in the same bath, the following experiments were conducted:

[0095] Experiment 1

[0096] The cationic polyurethane modified silicone oil obtained in Example 6 was emulsified to prepare a cationic hydrophilic softener, which was then used for the same-bath dyeing and softening finishing of nylon fabrics, as detailed below:

[0097] S1. Take 20 g of the cationic polyurethane modified silicone oil prepared in Example 6, add 5 g of emulsifier isomeric alcohol XL-50 while stirring, and add 67 ml of ice water for emulsification. Use magnetic stirring and high-speed shear emulsification for 1 h to obtain a hydrophilic softener.

[0098] S2. Dye the nylon fabric at 90℃ for 1 hour. Without draining, add 20g / L of hydrophilic softener and immerse the fabric fully in the dye bath and finishing solution for 20 minutes. Bake at 140℃ for 160 seconds. Soap at 90℃ for 10 minutes. Wash with water and air dry to obtain the hydrophilic softening finished nylon fabric.

[0099] The blank sample was dyed at 90℃ for 1 hour, then removed. It was then baked at 140℃ for 160 seconds, followed by soaping at 90℃ for 10 minutes. After washing and drying, the hydrophilic softening nylon fabric was obtained.

[0100] Experiment 2: The cationic polyurethane modified silicone oil in Experiment 1 was replaced with the cationic polyurethane modified silicone oil prepared in Example 8.

[0101] Experiment 3: Change the concentration of the finishing solution in Experiment 1 from "20 g / L" to "30 g / L", and keep the rest the same as in Experiment 1.

[0102] Experiment 4: Change the concentration of the finishing solution in Experiment 1 from "20 g / L" to "10 g / L", and keep the rest the same as in Experiment 1.

[0103] Experiment 5: Change "baking at 140 ℃ for 160 s" in Experiment 1 to "baking at 160 ℃ for 160 s", and keep the rest the same as Experiment 1.

[0104] Experiment 6: Change "baking at 140 ℃ for 160 s" in Experiment 1 to "baking at 140 ℃ for 140 s", and keep the rest the same as Experiment 1.

[0105] In the comparative experiment, the phrase "the cationic block copolymer silicone oil obtained in Example 1 was emulsified to prepare a hydrophilic softening agent" in Experiment 1 was changed to "the commercially available organosilicon hydrophilic softening agent". The rest was the same as in Experiment 1.

[0106] Example 6: Photograph of the nylon fabric after dyeing and softening treatment (see example). Figure 2 As shown, the blank sample only dyes nylon fabric that has not undergone the same bath softening treatment, such as... Figure 1 As shown; the difference in k / s values ​​can only be seen by a machine.

[0107] The nylon fabrics treated in experiments 1-6 and the comparative experiment, as well as the original nylon fabrics used, were tested in terms of water droplet diffusion time, softness, whiteness, and K / S. The results are shown in Table 3.

[0108] Table 3 Test results of treated nylon fabrics

[0109]

[0110] As can be seen from the data in Table 3, the hydrophilic softener works best at a concentration of 20-30 g / L and a baking temperature of 140℃ for 160 seconds, resulting in the best hydrophilic softening effect on the treated nylon fabric.

[0111] First, the softener of Example 1 of this invention, after being added to a high-temperature (90°C), acidic (pH=4) dyeing bath, maintained a clear and stable dye bath system, with no demulsification, oil separation, or flocculation observed. After finishing, the equipment was clean and free of residue. In contrast, the softeners of Comparative Examples 1 and 2 rapidly demulsified upon addition to the dye bath, forming an oily substance that adhered to the beaker wall (simulating the "residue sticking" phenomenon). This demonstrates that the softener of this invention overcomes the shortcomings of existing softeners, such as poor stability in acidic dye baths and easy demulsification due to interaction with anionic substances, thus meeting the stringent requirements of dyeing bath processes.

[0112] Secondly, regarding the fabric finishing effect, the nylon fabrics finished with the products of Examples 6-8 of this invention all achieved excellent softness and smoothness, maintained the original excellent whiteness of the fabric (whiteness value was basically the same as the blank sample), and were endowed with excellent hydrophilicity (water absorption time less than 5 seconds). In contrast, the comparative product had limited improvement in hand feel and had a negative impact on fabric whiteness; the finished fabric was significantly inferior to the fabric finished with this product.

[0113] It is worth noting that the softener of this invention brings unexpected positive technical effects. As can be seen from the K / S value (apparent dyeing depth) data, compared with the blank sample (K / S=15.796), the K / S values ​​of the fabrics treated by Examples 6-8 of this invention are significantly improved (up to a maximum of 16.91), indicating that the softener of this invention not only does not affect dyeing but also has a certain deepening effect, which is of great significance for increasing the added value of the product. In contrast, the comparative product resulted in a decrease in the K / S value and exhibited a "color peeling" phenomenon.

[0114] In summary, the comprehensive comparison results of the examples and comparative examples fully demonstrate that the cationic hydrophilic softener for nylon dyeing in the same bath provided by the present invention has high stability in high-temperature acidic dyeing baths, good compatibility with anionic systems, and can impart excellent softness, hydrophilicity and whiteness to fabrics, while also having a deepening effect. It is a textile auxiliary agent with comprehensive performance and is particularly suitable for green and efficient one-step dyeing processes in the same bath.

Claims

1. A method for preparing a cationic hydrophilic softener for dyeing nylon in the same bath, characterized in that... The method includes the following steps: S1. Preparation of terminal epoxy polyether silicone oil: Hydrosilylation reaction of terminal hydrogen-containing silicone oil with allyl epoxy polyether is carried out in the presence of platinum catalyst to obtain terminal epoxy polyether silicone oil. S2. Preparation of cationic polyurethane modified silicone oil: A polyol containing hydroxyl groups is reacted with a polyisocyanate under the action of a first catalyst to generate a -NCO-terminated polyurethane prepolymer. A chain extender containing tertiary amine groups is added to the polyurethane prepolymer for reaction; terminal epoxy polyether silicone oil obtained from S1 is added for reaction, followed by neutralization with acid to obtain cationic polyurethane modified silicone oil; The total molar ratio n(-NCO):n(-OH) of the -NCO group in the polyisocyanate to the -OH group in the hydroxyl-containing polyol and the chain extender containing tertiary amine groups is 0.2:1 to 1:1; S3. Emulsification: The cationic polyurethane modified silicone oil obtained in S2 is mixed with an emulsifier and water is added for emulsification to obtain the cationic hydrophilic softener for nylon dyeing bath.

2. The preparation method according to claim 1, characterized in that: In S1, the molar ratio of Si-H groups in the hydrogen-terminated silicone oil to C=C double bonds in the allyl epoxy polyether is 1:1.0-1.

1.

3. The preparation method according to claim 1 or 2, characterized in that: In S2, the polyol containing hydroxyl groups is polypropylene glycol, the polyisocyanate is isoflurane diisocyanate, and the chain extender containing tertiary amine groups is triethanolamine. The first catalyst is dibutyltin dilaurate (DBTDL).

4. The preparation method according to claim 1, characterized in that: The total molar ratio n(-NCO):n(-OH) of the -NCO group in the polyisocyanate to the -OH group in the hydroxyl-containing polyol and the tertiary amine-containing chain extender is 0.6:

1.

5. The preparation method according to claim 1, characterized in that: In S2, the amount of the terminal epoxy polyether silicone oil is 10% to 50% of the total mass of the reactants in S2.

6. The preparation method according to claim 5, characterized in that: The amount of the terminal epoxy polyether silicone oil is 20-30% of the total mass of the reactants in S2.

7. The preparation method according to claim 3, characterized in that... The specific operating conditions for S2 are as follows: At 40-50°C, the polypropylene glycol and the isoflurone diisocyanate are reacted for 30-90 minutes in the presence of dibutyltin dilaurate catalyst to generate the -NCO-terminated polyurethane prepolymer. The triethanolamine was then added, and the temperature was raised to 80°C and maintained for 1-4 hours. Cool to 40°C and add acetic acid for neutralization.

8. A cationic hydrophilic softener for nylon dyeing in the same bath, prepared by the method of claim 1, characterized in that, It is an oil-in-water emulsion containing cationic polyurethane-modified silicone compounds, emulsifiers, and water; The structure of the cationic polyurethane-modified organosilicon compound includes: The polysiloxane backbone is polymerized from hydrogen-terminated silicone oil; The cationic polyurethane segments formed by the reaction of polypropylene glycol, isoflurone diisocyanate and triethanolamine are grafted onto the ends of the polysiloxane backbone via hydrosilylation reaction. The cationic polyurethane segment contains a tertiary amine group that is neutralized by acid and carries a positive charge.

9. The softener according to claim 8, characterized in that: The average particle size of the emulsion is 90-250 nm.

10. The use of the cationic hydrophilic softener for dyeing nylon in the same bath as described in claim 8 or 9 for dyeing and finishing nylon fabrics in the same bath, characterized in that, This includes adding the softener directly to the dye bath after the acid dyeing step without changing the dye bath for softening and finishing.

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