A dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather and its use method

Abstract

The present invention discloses a dye penetrant for improving the dyeing performance of waterborne polyurethane microfiber leather and a method for using the dye penetrant, belonging to the technical field of textile chemicals. The dye penetrant comprises the following raw materials by weight: 5-40 wt% of an imidazolinone compound, 5-25 wt% of a pyrrolidone compound, 1-5 wt% of a nonionic surfactant, 1-2 wt% of a defoaming agent, 0.1-2 wt% of a conditioning agent, and 30-85 wt% of distilled water. The dye penetrant can improve the dyeing performance of waterborne polyurethane microfiber leather.

Description

Technical Field

[0001] The invention belongs to the technical field of textile chemicals, and in particular relates to a dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather and a use method thereof. Background Art

[0002] In recent years, with the continuous improvement of people's quality of life, the demand for leather products in various fields has also increased. As the product that is most similar to natural leather, microfiber synthetic leather has a wide range of applications in industries such as home furnishings, clothing, and automotive accessories. Because solvent-based polyurethane microfiber leather produces a large amount of volatile organic compounds (VOCs) during the production process, which affects the environment and human health, the development of green and environmentally friendly water-based polyurethane microfiber leather products is gaining increasing attention.

[0003] However, due to the large amount of hydrophilic monomers introduced into the structure of self-emulsifying waterborne polyurethane, the dyeability of microfiber leather prepared from it is significantly different from that of solvent-based polyurethane. Waterborne polyurethane microfiber leather has a low dye uptake rate, poor color fastness, and difficulty in fixing color. In particular, thick and heavy waterborne polyurethane microfiber leather has poor dye penetration, and the leather after dyeing has a light color or a white core.

[0004] Due to the special structure and properties of waterborne polyurethane, the dyeing process of waterborne polyurethane microfiber leather is difficult to learn from the experience and methods of solvent-based microfiber leather, and the above problems are difficult to be effectively solved. Therefore, it is urgent to develop a dyeing agent that can improve the dyeing performance of waterborne polyurethane microfiber leather. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, the present invention provides a dye penetrant for improving the dyeing performance of waterborne polyurethane microfiber leather and a method for its use. The dye penetrant is simple to prepare, produces a stable product, and is suitable for use with both acid dyes and acid mordant dyes. It achieves excellent dye penetration for a variety of waterborne polyurethane microfiber leathers, while maintaining minimal impact on dye uptake and color fastness, and maintaining the physical and mechanical properties of the dyed product. Furthermore, the dyeing process is pollution-free.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather comprises the following raw materials in percentage by mass: 5-40 wt% of an imidazolidinone compound, 5-25 wt% of a pyrrolidone compound, 1-5 wt% of a nonionic surfactant, 1-2 wt% of a defoaming agent, 0.1-2 wt% of a regulator, and 30-85 wt% of distilled water.

[0008] Preferably, the imidazolidinone compound is N,N-dimethyl-2-imidazolidinone.

[0009] Preferably, the pyrrolidone compound is N-methylpyrrolidone.

[0010] Preferably, the nonionic surfactant is a polyethylene glycol, polyol or polyether surfactant.

[0011] Preferably, the defoaming agent is a polyether-type, silicone-type or polyether-modified silicone-type defoaming agent; the regulating agent is polyethylene glycol, polyvinyl pyrrolidone or polyacrylamide, and the molecular weight of the polymer is between 5000 and 500,000.

[0012] The present invention also provides a method for preparing the penetrant for improving the dyeing performance of water-based polyurethane microfiber leather, comprising the following steps: at room temperature, adding an imidazolidinone compound and a pyrrolidone compound to distilled water under stirring, adding a non-ionic surfactant and a defoaming agent after mixing, and continuing to mix; then raising the system temperature to 60-80°C, adding a regulator, stirring evenly, and cooling to obtain the penetrant for improving the dyeing performance of water-based polyurethane microfiber leather.

[0013] Furthermore, more specific steps include first adding distilled water to a flask with an agitator, a condenser and a thermometer at room temperature, slowly adding imidazolidinone compounds and pyrrolidone compounds in sequence while stirring, mixing evenly, continuing to add non-ionic surfactants and defoaming agents, continuing to mix evenly, raising the temperature to 60-80°C, adding a regulator in small amounts multiple times, stirring evenly, and cooling to obtain a penetrant that improves the dyeing performance of water-based polyurethane microfiber leather.

[0014] The present invention also provides an application of the dye penetrant for improving the dyeing performance of waterborne polyurethane microfiber leather in the preparation of waterborne microfiber polyurethane synthetic leather.

[0015] The present invention also provides a method for using the dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather, which includes four methods, and the specific steps are as follows:

[0016] Method 1: Immerse the water-based microfiber polyurethane synthetic leather in a 5-30wt% aqueous solution of a penetrant, roll and press, repeat the immersion, drying and dyeing to obtain a sample;

[0017] Method 2: Immerse the water-based microfiber polyurethane synthetic leather in a 5-30wt% aqueous solution of a penetrant for 0-15 minutes, dye, and obtain a sample; this method refers to placing the water-based microfiber polyurethane synthetic leather in a penetrant for pretreatment, and then dyeing it with the penetrant. 0 minutes means no pretreatment in advance, and a certain amount of penetrant is directly added during the dyeing stage for the dyeing process, which means a one-bath dyeing process (the same below);

[0018] Method 3: Immersing the water-based microfiber polyurethane synthetic leather in a 5-30wt% aqueous solution of a penetrant, rolling with a roller, repeating the immersion, and drying; then immersing the water-based microfiber polyurethane synthetic leather in a 5-30wt% aqueous solution of a penetrant for 0-15 minutes, dyeing, and obtaining a sample;

[0019] Method 4: Immerse the water-based microfiber polyurethane synthetic leather in a 5-30wt% aqueous solution of a penetrant, roll it, repeat the rolling, dry it, dye it at 95°C for 30 minutes, then cool it to 25°C and keep it warm for 12 hours to obtain a sample.

[0020] Preferably, the dyes used in the dyeing process are all acid dyes or neutral dyes.

[0021] The imidazolinone and pyrrolidone compounds in the present invention can effectively inhibit the swelling degree of waterborne polyurethane in the dyeing process of microfiber leather, facilitate the penetration and diffusion of dye liquor into the interior of microfiber leather, and improve the migration property of dye; nonionic surfactant can improve the wettability and permeability of dye liquor to microfiber leather; defoamer can eliminate foam that may be generated during padding process, and obtain more accurate liquid pick-up rate; regulator can more accurately control the liquid pick-up rate under padding process conditions and the distribution of dye penetrant in microfiber leather by adjusting the viscosity of dye penetrant. The effect of dye penetrant is mainly manifested in: after thick and heavy waterborne polyurethane microfiber leather is treated with dye penetrant, the dye penetrant is significantly improved, especially the color of thick and heavy products is consistent inside and outside, and there is no phenomenon of light color or white core inside; dye uptake is not affected, especially when the dye concentration is relatively high, the dye uptake is higher than that of products without using the dye penetrant; dry and wet friction color fastness of the product is not affected; color shade is not affected; physical and mechanical properties, feel, style characteristics of the product are not affected; and it does not affect the post-finishing process and finishing effect. In general, the dye penetrant can improve the dyeing performance of water-based polyurethane microfiber leather. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0023] Figure 1 This is the dyeing process curve of the embodiment of the present invention. DETAILED DESCRIPTION

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0026] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0027] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the present invention. The present description and examples are intended to be illustrative only.

[0028] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0029] Unless otherwise specified, the "room temperature" and "normal temperature" mentioned in the present invention are all calculated as 25±2°C.

[0030] The raw materials used in the following examples of the present invention are all commercially available.

[0031] The invention provides a dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather. The dye penetrant comprises the following raw materials in percentage by mass: 5-40 wt% of an imidazolidinone compound, 5-25 wt% of a pyrrolidone compound, 1-5 wt% of a nonionic surfactant, 1-2 wt% of a defoaming agent, 0.1-2 wt% of a regulator and 30-85 wt% of distilled water.

[0032] Preferably, the penetrant for improving the dyeing performance of water-based polyurethane microfiber leather comprises the following raw materials in percentage by mass: 17 wt% of imidazolidinone compounds, 8 wt% of pyrrolidone compounds, 2 wt% of nonionic surfactants, 1 wt% of defoaming agents, 0.5 wt% of regulators and 71.5 wt% of distilled water.

[0033] In some preferred embodiments of the present invention, the imidazolidinone compound is N,N-dimethyl-2-imidazolidinone. The pyrrolidone compound is N-methylpyrrolidone.

[0034] In some preferred embodiments of the present invention, the nonionic surfactant is a polyethylene glycol, polyol or polyether surfactant, preferably a polyethylene glycol surfactant, such as fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ether, etc. The specific selection is not the inventive point of the present invention. Such surfactants can achieve the same performance. For further clarification, the nonionic surfactant used in the following embodiments of the present invention is fatty alcohol polyoxyethylene ether JFC.

[0035] In some preferred embodiments of the present invention, the defoamer is a polyether-type, silicone-type or polyether-modified silicone-type defoamer, preferably a polyether-modified silicone-type defoamer, such as Si-OC-type defoamer and Si-C-type defoamer. The specific selection is not the inventive point of the present invention. Such defoamers can achieve the same performance. For further clarification, the defoamer used in the following embodiments of the present invention is a polyether-modified polysiloxane-type defoamer BYK024.

[0036] In some preferred embodiments of the present invention, the regulator is polyethylene glycol, polyvinyl pyrrolidone or polyacrylamide, and the molecular weight of the polymer is between 5000 and 500000, preferably polyvinyl pyrrolidone.

[0037] The present invention also provides a preparation method of the dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather, comprising the following steps: at room temperature, first adding 30-85% of distilled water into a flask equipped with a stirrer, a condenser and a temperature controller, slowly adding 5-40% of an imidazolinone compound and 5-25% of a pyrrolidone compound in sequence while stirring, and adding them within 3-5 minutes depending on the amount of reagents used, and the stirring speed is sufficient to ensure a stable liquid level; after uniform mixing, continuously adding 1-5% of a non-ionic surfactant and 1-2% of a defoaming agent, and the defoaming agent can be added first and then the non-ionic surfactant; after uniform mixing, raising the temperature to 60-80°C, adding 0.1-2% of a regulator in small amounts and multiple times, stirring thoroughly and evenly, making sure that the added polymer particles are completely dissolved, ensuring a stable liquid level during the stirring process, and cooling to room temperature to obtain the dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather.

[0038] The present invention also provides an application of the dye-permeating agent for improving the dyeing performance of water-based polyurethane microfiber leather in the preparation of water-based microfiber polyurethane synthetic leather. The water-based microfiber polyurethane synthetic leather is prepared from self-emulsifying water-based polyurethane and an external emulsifier. Self-emulsifying water-based polyurethane refers to a polyurethane that can be emulsified in water without adding an emulsifier by introducing water-soluble groups such as sulfonic acid groups (roots) and carboxylic acid groups (roots) into the polyurethane molecule through water-based monomers during the polyurethane polymerization process. The preparation method of the water-based microfiber polyurethane synthetic leather is not an innovative point of the present invention and can be prepared by conventional methods in the field, and the details will not be repeated.

[0039] The present invention also provides a method for using the dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather, which can help the dye penetrant fully exert its due effect and obtain the best cost-effectiveness, including the following four methods, and the specific steps are as follows:

[0040] Method 1: Padding pretreatment-dyeing process: immerse the water-based microfiber polyurethane synthetic leather in a penetrant aqueous solution with a concentration of 5-30wt% (preferably 15-25wt%, more preferably 15wt% or 25wt%), and press it with a padder (roller) to control the liquid rate to be 35-100% (preferably 42-45%). The padding process can be repeated many times (3-5 times are recommended, preferably 3 times), and dried, and the drying temperature does not exceed 90°C (preferably 80°C). Then dye and finish according to the conventional immersion dyeing process. During the dyeing process, the water-based microfiber leather can be rope-dyed or flat-width dyed. For water-based microfiber polyurethane synthetic leather, especially relatively thick and tightly structured products, it is first pretreated by a padding process and then dyed by a conventional process.

[0041] Method 2: One-bath dyeing process: Immerse the water-based microfiber polyurethane synthetic leather in a 5-30wt% (preferably 25wt%) aqueous solution of a penetrant for 0-15 minutes (preferably 0 minutes, i.e., adding the penetrant directly to the dyeing process), and then dye according to the conventional exhaust dyeing process and finish. During the dyeing process, the water-based microfiber leather can be rope-dyed or open-width dyed.

[0042] Method 3: Pretreatment-same-bath combined dyeing process: immersing the water-based microfiber polyurethane synthetic leather in a penetrant aqueous solution with a concentration of 5-30wt% (preferably 15wt%), rolling with a roller, repeating the immersion and drying; then immersing the water-based microfiber polyurethane synthetic leather in a penetrant aqueous solution with a concentration of 5-30wt% (preferably 25wt%) for 0-15 minutes (preferably 0 minutes), dyeing, and obtaining a sample;

[0043] Method 4: Immerse the water-based microfiber polyurethane synthetic leather in a 5-30wt% (preferably 15wt%) aqueous solution of a penetrant, roll it, repeat the rolling, dry it, dye it at 95°C for 30 minutes, then cool it to 25°C and keep it warm for 12 hours to obtain a sample.

[0044] The dye used in the above dyeing process is an acid dye or a neutral dye (acid mordant dye).

[0045] In the following examples, the imidazolidinone compound used is N, N-dimethyl-2-imidazolidinone (manufactured by Hebei Kangzhuang Environmental Protection Technology Co., Ltd.), the pyrrolidone compound is N-methylpyrrolidone (manufactured by Tianjin Komeiou Reagent Co., Ltd.), the nonionic surfactant is JFC (manufactured by Tianjin Gongda Textile Auxiliary Agent Co., Ltd.), the defoaming agent is BYK-024 (manufactured by BYK, Germany), and the regulating agent is polyvinyl pyrrolidone (manufactured by Tianjin Komeiou Reagent Co., Ltd.), and the molecular weight is 10,000.

[0046] The following examples serve as further illustrations of the technical solutions of the present invention.

[0047] The K / S value is the ratio of the colorant absorption coefficient k to the colorant scattering coefficient s, and is usually used to indicate the depth of color on the surface of a solid sample, that is, the concentration of the colored substance.

[0048] Example 1

[0049] A dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather comprises the following raw materials in percentage by mass: 17 wt% of an imidazolidinone compound, 8 wt% of a pyrrolidone compound, 2 wt% of a nonionic surfactant, 1 wt% of a defoaming agent, 0.5 wt% of a regulator, and 71.5 wt% of distilled water.

[0050] Preparation of a penetrant: At room temperature, 71.5 wt% of distilled water is first added to a flask equipped with a stirrer, a condenser, and a thermometer. While stirring, 17 wt% of N,N-dimethyl-2-imidazolidinone and 8 wt% of N-methylpyrrolidone are slowly added in sequence over 5 minutes. After uniform mixing, 2 wt% of a polyether-type nonionic surfactant and 1 wt% of a polyether-modified silicone defoamer are added in sequence. After uniform mixing, the temperature is raised to 60°C, 0.5% of polyvinylpyrrolidone is added three times by weight, and the mixture is thoroughly stirred to completely dissolve the polymer particles. After stirring for 30 minutes, the mixture is cooled to room temperature to obtain a penetrant.

[0051] How to use the penetrant (pad pretreatment-dyeing process):

[0052] (1) Water-based microfiber polyurethane synthetic leather (water-based polyurethane polyamide 6 microfiber leather, unit area mass 702g / m2 ) immersed in a 15wt% aqueous solution of a penetrant, and passed through a padding machine to control the liquid rate to 42%, three times of dipping and three times of padding, and then dried at 80°C for 5 minutes and immediately dyed;

[0053] (2) Dyeing process: The dye is acid blue MD-R, which is a weak acid dye. The dye concentration is 3% owf, the dye bath pH is 6.5, the JFC is 1g / L, the heating rate is 2℃ / min, and the bath ratio is 1:30. After dyeing, the dye is washed and dried. The dyeing process curve is as follows: Figure 1 shown.

[0054] Samples dyed using this process exhibit excellent dye penetration, with a dye uptake of 80.9%. Color remains unchanged, and the K / S ratio increases compared to samples without pretreatment. Dry rubbing color fastness is 3.5, and wet rubbing color fastness is 2.5-3. The strength of the water-based microfiber polyurethane synthetic leather remains unchanged, with a slight decrease in tensile elongation at break.

[0055] Example 2

[0056] The formula and preparation method of the penetrant are the same as those in Example 1.

[0057] How to use the penetrant (pad pretreatment-dyeing process):

[0058] (1) Water-based microfiber polyurethane synthetic leather (water-based polyurethane polyamide 6 microfiber leather, unit area mass 702g / m 2 ) immersed in a 15wt% aqueous solution of a penetrant, and passed through a padding machine to control the liquid rate to 42%, three times of dipping and three times of padding, and then dried at 80°C for 5 minutes and immediately dyed;

[0059] (2) Dyeing process: The dye is acid blue MD-R, which is a weak acid dye. The dye concentration is 1% owf, the dye bath pH is 6.5, the JFC is 1g / L, the heating rate is 2℃ / min, and the bath ratio is 1:30. After dyeing, the dye is washed and dried. The dyeing process curve is as follows: Figure 1 shown.

[0060] The samples dyed using this process showed excellent dye penetration, a dye uptake of 89.2%, no color change, an increase in K / S compared to the untreated samples, and a dry rubbing color fastness of 4 and a wet rubbing color fastness of 3. The strength of the microfiber leather remained unchanged, but the tensile elongation at break was slightly reduced.

[0061] Example 3

[0062] The formula and preparation method of the penetrant are the same as those in Example 1.

[0063] How to use the penetrant (pad pretreatment-dyeing process):

[0064] (1) Water-based microfiber polyurethane synthetic leather (water-based polyurethane polyamide 6 microfiber leather, unit area mass 702g / m 2 ) immersed in a 15wt% aqueous solution of a penetrant, and passed through a padding machine to control the liquid rate to 42%, three times of dipping and three times of padding, and then dried at 80°C for 5 minutes and immediately dyed;

[0065] (2) Dyeing process: The dye is Isolon Gray K-PBL, an acidic mordant dye (neutral dye), the dye concentration is 3% owf, the dye bath pH is 6.8, the JFC is 1g / L, the heating rate is 2℃ / min, and the bath ratio is 1:30. After dyeing, the dye is washed and dried. The dyeing process curve is as follows Figure 1 shown.

[0066] The samples dyed using this process showed excellent dye penetration, a dye uptake of 84.9%, no color change, an increase in K / S compared to the untreated samples, and a dry rubbing color fastness of 3.5 and a wet rubbing color fastness of 3. The strength of the microfiber leather remained unchanged, but the tensile elongation at break was slightly reduced.

[0067] Example 4

[0068] The formula and preparation method of the penetrant are the same as those in Example 1.

[0069] How to use the penetrant (same-bath dyeing process):

[0070] Water-based microfiber polyurethane synthetic leather (water-based polyurethane polyamide 6 microfiber leather, unit area weight 509g / m 2 ) as the raw material for dyeing, the dye is acid blue MD-R, a weak acid dye, the dye concentration is 3% owf, the mass percentage concentration of the penetrant is 25%, the dye bath pH is 6.5, the heating rate is 2°C / min, and the bath ratio is 1:30. After dyeing, it is washed and dried. The dyeing process curve is as follows Figure 1 shown.

[0071] Samples dyed using this process exhibited excellent dye penetration, with a dye uptake of 81.4%. The color remained unchanged, and the K / S ratio increased compared to the untreated samples. Dry rubbing color fastness was 3.5, and wet rubbing color fastness was 2.5-3. The strength of the microfiber leather remained unchanged, but the tensile elongation at break was slightly reduced.

[0072] Example 5

[0073] The formula and preparation method of the penetrant are the same as those in Example 1.

[0074] How to use the penetrant (pretreatment-same-bath combined dyeing process):

[0075] (1) Water-based microfiber polyurethane synthetic leather (water-based polyurethane polyamide 6 microfiber leather, unit area mass 702g / m2 ) immersed in a 15wt% aqueous solution of a penetrant, and then pressed by a padder to control the liquid rate to 45%, three times immersed and three times pressed, and then dried at 80°C for 5 minutes, and then dyed in the same bath;

[0076] (2) One-bath dyeing process: The dye is acid blue MD-R, a weak acid dye, the dye concentration is 3% owf, the mass percentage concentration of the penetrant is 25%, the dye bath pH is 6.5, the heating rate is 2°C / min, and the bath ratio is 1:30. After dyeing, the dye is washed and dried. The dyeing process curve is as follows: Figure 1 shown.

[0077] Samples dyed using this process exhibited excellent dye penetration, a dye uptake of 84.5%, no color change, and an increased K / S ratio compared to samples without pretreatment. Dry rubbing color fastness was 3.5, and wet rubbing color fastness was 2.5-3. The strength of the microfiber leather remained unchanged, but the tensile elongation at break was slightly reduced.

[0078] Example 6

[0079] The formula and preparation method of the penetrant are the same as those in Example 1.

[0080] How to use the penetrant (pretreatment-low temperature exhaustion dyeing process):

[0081] (1) Water-based microfiber polyurethane synthetic leather (water-based polyurethane polyamide 6 microfiber leather, unit area mass 509g / m 2 ) immersed in a 15wt% aqueous solution of a penetrant, and then pressed by a padder to control the liquid rate to 43%, three times of dipping and three times of pressing, and then dried at 80°C for 5 minutes, and then low-temperature dyeing;

[0082] (2) Dyeing process: The dye is acid blue MD-R, which is a weak acid dye, the dye concentration is 3% owf, the dye bath pH is 6.5, the penetrant is 1 g / L, the bath ratio is 1:30, the dyeing temperature is 95°C, and the dyeing time is 30 minutes; then the temperature is lowered to 25°C and kept warm for 12 hours. After dyeing, the dye is washed and dried.

[0083] The samples dyed using this process showed excellent dye penetration, a dye uptake of 91.9%, no color change, an increase in K / S ratio compared to the untreated samples, and dry rubbing color fastness of 3.5 and wet rubbing color fastness of 2.5. The strength of the microfiber leather remained unchanged, but the tensile elongation at break was slightly reduced.

[0084] Example 7

[0085] A dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather comprises the following raw materials in percentage by mass: 10 wt% of an imidazolidinone compound, 10 wt% of a pyrrolidone compound, 2 wt% of a nonionic surfactant, 1% of a defoaming agent, 0.5% of a regulator, and 76.5 wt% of distilled water.

[0086] The preparation method of the penetrant is the same as that in Example 1.

[0087] The method of using the penetrant is the same as in Example 1.

[0088] The samples dyed using this process exhibited excellent dye penetration, a dye uptake of 85.6%, no color change, and an increased K / S ratio compared to the untreated samples. Their dry rubbing color fastness was 3.5, and their wet rubbing color fastness was 3.0. The strength of the water-based microfiber polyurethane synthetic leather remained unchanged, but its tensile elongation at break was slightly reduced.

[0089] Example 8

[0090] A dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather comprises the following raw materials in percentage by weight: 20% imidazolidinone compound, 5% pyrrolidone compound, 2% nonionic surfactant, 1% defoaming agent, 0.5% regulator and 71.5% distilled water.

[0091] The preparation method of the penetrant is the same as that of Example 1.

[0092] The method of using the penetrant is the same as in Example 1.

[0093] Samples dyed using this process exhibit excellent dye penetration, a dye uptake of 78.5%, no color change, and an increased K / S ratio compared to samples without pretreatment. Dry rubbing color fastness is 3.5, and wet rubbing color fastness is 2.5-3. The strength of the water-based microfiber polyurethane synthetic leather remains unchanged, but the tensile elongation at break is slightly reduced.

[0094] Example 9

[0095] The formula and preparation method of the penetrant are the same as those in Example 1.

[0096] How to use the penetrant (same-bath dyeing process):

[0097] Water-based microfiber polyurethane synthetic leather (water-based polyurethane polyamide 6 microfiber leather, unit area mass 509g / m 2 ) was pretreated by immersing in a 25 wt% aqueous solution of a penetrant for 10 minutes, and then dyeing was performed. The dye was Acid Blue MD-R, a weakly acidic dye, with a dye concentration of 3% owf, a dye bath pH of 6.5, a heating rate of 2°C / min, and a bath ratio of 1:30. After dyeing, the dye was washed and dried. The dyeing process curve is shown in FIG. Figure 1 shown.

[0098] Samples dyed using this process exhibited excellent dye penetration, with a dye uptake of 88.2%. Color remained unchanged, and the K / S ratio increased compared to samples without pretreatment. Dry rubbing color fastness was 3.5, and wet rubbing color fastness was 2.5-3. The strength of the water-based microfiber polyurethane synthetic leather remained unchanged, with a slight decrease in tensile elongation at break.

[0099] Comparative Example 1

[0100] A dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather comprises the following raw materials in percentage by mass: 3wt% of an imidazolidinone compound, 3wt% of a pyrrolidone compound, 2wt% of a nonionic surfactant, 1wt% of a defoaming agent, 0.5wt% of a regulator, and 90.5wt% of distilled water.

[0101] The preparation method of the penetrant is the same as that in Example 1.

[0102] The method of using the penetrant is the same as in Example 1.

[0103] The dyed samples treated with this process showed no significant change in dye penetration, with the intermediate color noticeably lighter than the surface color. Dye uptake was 87.5%, with no color change. K / S ratios did not significantly increase compared to the untreated samples. Dry rubbing color fastness was 3.5, and wet rubbing color fastness was 2.5-3. The strength of the water-based microfiber polyurethane synthetic leather remained unchanged, with a slight decrease in tensile elongation at break.

[0104] Comparative Example 2

[0105] A dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather comprises the following raw materials in percentage by mass: 0wt% of an imidazolidinone compound, 0wt% of a pyrrolidone compound, 2wt% of a nonionic surfactant, 1wt% of a defoaming agent, 0.5wt% of a regulator, and 96.5wt% of distilled water.

[0106] The preparation method of the penetrant is the same as that of Example 1.

[0107] The method of using the penetrant is the same as in Example 1.

[0108] The dyeing process for the sample showed no change in dye penetration, with a white core inside. The dye uptake was 87.7%, with no color change. The K / S ratio increased significantly compared to the untreated sample. The dry rubbing color fastness was level 3, and the wet rubbing color fastness was level 2.5. The strength of the water-based microfiber polyurethane synthetic leather remained unchanged, but the tensile elongation at break was slightly reduced.

[0109] Comparative Example 3

[0110] The raw material composition of the penetrant is the same as that of Example 1.

[0111] Preparation method of the penetrant: at room temperature, distilled water is first added to a flask equipped with a stirrer, a condenser and a temperature controller, and N,N-dimethyl-2-imidazolidinone and N-methylpyrrolidone are slowly added in sequence while stirring, and the addition is completed within 5 minutes; after mixing evenly, a polyether-type nonionic surfactant and a polyether-modified silicone-type defoaming agent are added in sequence; after stirring for 30 minutes, the temperature is cooled to room temperature to obtain the penetrant.

[0112] The method of using the penetrant is the same as in Example 1.

[0113] Samples dyed using this process exhibit excellent dye penetration, a dye uptake of 78.9%, and no color change. The K / S ratio increases compared to samples without pretreatment, but levelness decreases. Dry rubbing color fastness is level 3, and wet rubbing color fastness is level 2.5. The strength of the water-based microfiber polyurethane synthetic leather remains unchanged, but the tensile elongation at break decreases slightly.

[0114] Comparative Example 4

[0115] The formula and preparation method of the penetrant are the same as those in Example 1.

[0116] The preparation method of the penetrant is the same as that of Example 1.

[0117] How to use the penetrant (pad pretreatment-dyeing process):

[0118] (1) Water-based microfiber polyurethane synthetic leather (water-based polyurethane polyamide 6 microfiber leather, unit area mass 702g / m 2 ) Immerse in a 10 wt% aqueous solution of a penetrant, pass through a padding machine to control the liquid rate to 55%, perform three immersions and three paddings, then dry at 80°C for 5 minutes and dye immediately;

[0119] (2) Dyeing process: The dye is acid blue MD-R, a weak acid dye, the dye concentration is 3% owf, the dye bath pH is 6.5, the JFC is 1 g / L, the heating rate is 2°C / min, and the bath ratio is 1:30; after dyeing, the dye is washed with water and dried.

[0120] Samples dyed using this process showed improved dye penetration, but the core color was lighter. The dye uptake was 75.9%, with no color change. K / S ratio was lower than that of the untreated samples. Dry rubbing color fastness was 3.5, and wet rubbing color fastness was 2.5-3. The strength of the water-based microfiber polyurethane synthetic leather remained unchanged, but the tensile elongation at break was slightly reduced.

[0121] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather, characterized in that: The method comprises the following raw materials in percentage by weight: 5-40 wt% of an imidazolidinone compound, 5-25 wt% of a pyrrolidone compound, 1-5 wt% of a nonionic surfactant, 1-2 wt% of a defoaming agent, 0.1-2 wt% of a regulator, and 30-85 wt% of distilled water; The imidazolidinone compound is N,N-dimethyl-2-imidazolidinone; The pyrrolidone compound is N-methylpyrrolidone.

2. The dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather according to claim 1, wherein The nonionic surfactant is a polyol-type or polyether-type surfactant.

3. The dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather according to claim 1, wherein The nonionic surfactant is a polyethylene glycol surfactant.

4. The dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather according to claim 1, wherein The defoaming agent is a polyether type or polyether modified silicone type defoaming agent; the regulating agent is polyethylene glycol, polyvinyl pyrrolidone or polyacrylamide.

5. The dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather according to claim 1, characterized in that The defoamer is a silicone defoamer.

6. A method for preparing a dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather according to any one of claims 1 to 5, characterized in that: The following steps are involved: At room temperature, imidazolidinone compounds and pyrrolidone compounds are added to distilled water under stirring, mixed evenly, and then a non-ionic surfactant and a defoaming agent are added, and the mixing is continued; then the system temperature is raised to 60-80°C, a regulator is added, stirred evenly, and cooled to obtain a penetrant for improving the dyeing performance of water-based polyurethane microfiber leather.

7. Use of the dye penetrant for improving the dyeing performance of waterborne polyurethane microfiber leather as claimed in any one of claims 1 to 5 in the preparation of waterborne microfiber polyurethane synthetic leather.

8. A method for using the dye penetrant for improving the dyeing performance of water-based polyurethane microfiber leather according to any one of claims 1 to 5, characterized in that: There are four methods, the specific steps are as follows: Method 1: Immerse the water-based microfiber polyurethane synthetic leather in a 5-30wt% aqueous solution of a penetrant, roll it, repeat the rolling, drying, and dyeing to obtain a sample; Method 2: Immerse the water-based microfiber polyurethane synthetic leather in a 5-30wt% aqueous solution of a penetrant for 0-15 minutes, and dye to obtain a sample; wherein 0 minutes means that no pretreatment is performed in advance, and a certain amount of penetrant is added directly during the dyeing stage to carry out the dyeing process; Method 3: Immerse the water-based microfiber polyurethane synthetic leather in a 5-30wt% aqueous solution of a penetrant, roll and roll, repeat the immersion and rolling, and dry; then immerse the water-based microfiber polyurethane synthetic leather in a 5-30wt% aqueous solution of a penetrant for 0-15 minutes, dye, and obtain a sample; wherein 0 minutes means that no pretreatment is performed in advance, and a certain amount of penetrant is directly added during the dyeing stage for the dyeing process; Method 4: Immerse the water-based microfiber polyurethane synthetic leather in a 5-30wt% aqueous solution of a penetrant, roll it, repeat the rolling, dry it, dye it at 95°C for 30 minutes, then cool it to 25°C and keep it warm for 12 hours to obtain a sample.

9. The method of use according to claim 8, characterized in that: The dyes used in the dyeing process are all acid dyes or neutral dyes.

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