Durable flame-retardant dyeing and finishing method for cellulose-based yarns or fabrics

Abstract

The invention discloses a durable flame-retardant dyeing and finishing method for cellulose-based yarns or fabrics, and belongs to the technical field of textile dyeing and finishing. The method comprises the following specific steps: preparing a durable flame-retardant dyeing finishing liquid by using a water-soluble durable flame retardant system and an active dye, carrying out flame-retardant dyeing finishing on the fabric through immersion pressing and high-temperature curing, and combining a flame retardant and dye molecules to cellulose molecules through covalent bonds to obtain the durable flame-retardant dyed cotton fabric. Then, the fabric is subjected to one-step fluoride-free hydrophobic finishing, and the durable, flame-retardant and hydrophobic cotton fabric can be further obtained. The durable flame-retardant hydrophobic dyed fabric disclosed by the invention has excellent flame-retardant property, hydrophobic property, bright color and washing resistance. And after 500 times of water washing, flame retardance, hydrophobicity and color can still be well maintained. Meanwhile, the finishing method disclosed by the invention is mild in condition, cheap and easily available in raw materials, simple and convenient in process and suitable for large-scale industrial application.

Description

Technical Field

[0001] The invention belongs to the technical field of dyeing and finishing of cellulose-based fabrics, and in particular relates to a method for formaldehyde-free and fluorine-free durable dyeing, flame-retardant and hydrophobic finishing of cellulose-based yarn or fabric. Background Art

[0002] Cellulose-based fabrics (such as cotton fabrics, viscose fabrics, lyocell fabrics, cotton / viscose blended fabrics, etc.) are popular due to their excellent skin-friendliness, softness, moisture permeability and dyeability, and are widely used in many fields such as clothing, home textiles, medical treatment, and transportation. However, their flammability limits their application in certain fields and may pose a threat to people's lives and property. Therefore, flame retardant finishing and modification of cellulose-based fabrics and their front-end yarns is of great significance and value.

[0003] Cellulose-based fabrics are favored for their excellent moisture absorption, but this property also makes them vulnerable to water-based stains and easy to breed bacteria in humid environments, which not only affects the appearance and comfort of the fabric, but also shortens its service life. Therefore, it is particularly important to perform hydrophobic finishing on cellulose-based fabrics and yarns, which can not only improve the durability and cleanability of the fabric, but also enhance its stability and service life in humid environments.

[0004] Cellulose-based fabrics and yarns are mainly dyed with reactive dyes that can covalently bond with fibers. During dyeing, since both are negatively charged, adsorption is difficult, which affects the efficiency of dyeing and fixation. Traditionally, inorganic salts such as sodium chloride or sodium sulfate are added to reduce the negative charge of fibers and promote dye adsorption, but this increases the difficulty and cost of wastewater treatment and poses a threat to the environment. Therefore, reducing the use of inorganic salts while ensuring dyeing quality is an urgent problem to be solved in the printing and dyeing industry.

[0005] While giving cellulose-based fabrics multifunctional properties such as flame retardancy and hydrophobicity and dyeing, they also need to ensure durability. The fabrics can maintain their properties after long-term use and frequent washing, which not only enhances the life of the product, but also reduces the need for frequent replacement due to performance degradation, thereby reducing environmental impact and economic costs.

[0006] Many finishing strategies have been developed for flame retardant and hydrophobic finishing of cellulose-based fabrics, including impregnation, layer-by-layer self-assembly (LBL), sol-gel, graft copolymerization, plasma treatment, etc.; hydrophobic finishing also includes spraying, radiation grafting and chemical vapor deposition, etc. These finishing methods are widely used and mature. The main cellulose-based fabric dyeing technologies include: development of new dye molecular structures, low-salt dyeing auxiliaries, cellulose modification, low-salt and salt-free dyeing processes, and non-aqueous medium dyeing technology. For the durability of fabrics, the commonly used method is to combine the finishing agent with the fabric through chemical bonds to enhance its durability.

[0007] It is relatively easy to give a function (flame retardant, hydrophobic or dyeing) to cellulose fabrics, but it is very challenging to give the fabrics durable flame retardant, hydrophobic and dyeing functions, especially durability at the same time, which is a recognized technical problem in the field. CN118547502A discloses a durable flame retardant cotton fabric and an in-situ deposition cross-linking preparation method. Ammonium polyphosphate and tetrakishydroxymethylphosphonium chloride-dicyandiamide condensation product are combined by electrostatic attraction to form an insoluble precipitate, which is combined with cotton fibers by covalent bonds to prepare a durable flame retardant cotton fabric. However, this system has the problem of formaldehyde release. CN112553904B discloses a kind of phosphorus-containing fluorine-silicon super-hydrophobic flame-retardant cotton fabric and preparation method thereof, by photosensitive phosphorus-containing fluorine polymer and octaethylene-POSS under ultraviolet light initiation cross-linking polymerization, build phosphorus-containing fluorine-silicon cross-linked coating with micro-nano structure on cotton fabric, contain phosphorus, fluorine, silicon element in coating, effectively improve the flame retardant property of cotton fabric by synergistic effect, at the same time, the combination of fluorine, silicon element and coating surface micro-nano structure, make fabric have super-hydrophobic performance, but coating preparation process is cumbersome in this study, and contains fluorine element, is unfavorable for environmental protection. Although the above method prepares durable flame-retardant cotton fabric and super-hydrophobic flame-retardant cellulose-based fabric respectively, cellulose-based fabric is not provided with more functions, and preparation process is complicated, unfriendly to environment.

[0008] Therefore, the object of the present invention is to provide a low-cost, simple and environmentally friendly finishing method to obtain durable flame retardant, hydrophobic dyed cellulose-based fabrics, excluding formaldehyde emission and fluorine-containing systems. Summary of the invention

[0009] In order to solve the above technical problems, the purpose of the present invention is to provide a finishing method for cellulose-based yarn or fabric, wherein the yarn or fabric obtained by finishing is free of formaldehyde and fluorine, and its flame retardant, dyeing and hydrophobic properties are still good after multiple washings, wherein the flame retardant and dye are combined with the cellulose fabric through covalent bonds, and the hydrophobic agent is finished on the cellulose-based yarn or fabric through the sol-gel method, and the reaction generates covalent bonds, which provide it with excellent durability and make it firmly attached to the fabric. Through this simple method, while giving cellulose-based yarn or fabric a variety of functions and durability, it maintains cost-effectiveness, opening up new possibilities for the versatility and environmental protection of cellulose fabrics.

[0010] The technical solution adopted by the present invention is as follows:

[0011] A durable flame retardant dyeing and finishing method for cellulose-based yarn or fabric comprises the following steps:

[0012] The cellulose-based yarn or fabric is immersed in a finishing liquid, and after dipping and rolling, it is pre-cured at 90-110°C and baked at 150-170°C in sequence, and then washed with water to remove excess flame retardant and floating color, and dried to obtain a flame-retardant dyed fabric or yarn. The finishing liquid includes 150-250g / L flame retardant, 30-50g / L dicyandiamide, and 2.5-3.5g / L reactive dye. The flame retardant includes but is not limited to one or more of ammonium phosphate, low molecular weight ammonium polyphosphate (polymerization degree is less than 20), and ammonium phytate. The reactive dye is reactive red 120, reactive orange 16, or reactive blue 4.

[0013] The cellulose-based yarn or fabric is cotton fiber and yarn, viscose fiber and yarn or lyocell fiber and yarn, and the cellulose-based fabric is a fabric corresponding to the above-mentioned fibers and yarn.

[0014] Specifically, the one-dip-one-roll process is as follows: immersing the cellulose-based yarn or fabric in the finishing liquid, maintaining it at 60-80° C. for 20-30 minutes, and then rolling out the excess liquid with a rolling wheel.

[0015] Specifically, after dipping and rolling, pre-curing is performed at 90-110° C. for 20-40 minutes and baking is performed at 150-170° C. for 4-6 minutes.

[0016] Furthermore, desizing and mercerizing pretreatments are performed before the cellulose-based yarn or fabric is immersed in the finishing liquid. The pretreatment enables more hydroxyl groups to participate in the reaction, and the fabric is more likely to react with the flame retardant and dye, thereby improving the durability of dyeing and flame retardancy.

[0017] Furthermore, after the cellulose-based yarn or fabric is immersed in the finishing liquid, a hydrophobic finishing is performed, which not only improves the hydrophobicity of the fabric itself but also further improves its dyeing and flame retardant durability. Specifically, the durable flame retardant dyed fabric or yarn is immersed in a silane solution for finishing and dried to obtain a durable flame retardant hydrophobic dyed fabric or yarn.

[0018] The silane includes but is not limited to one or more of vinyl triethoxysilane, methyl triethoxysilane, triethoxyoctyl silane, dodecyl trimethoxysilane, hexadecyl trimethoxysilane, and octadecyl trimethoxysilane. The silane concentration in the silane solution is 10 to 50 g / L, and the durable flame retardant dyed fabric or yarn is finished in the silane solution for 2 to 5 minutes.

[0019] The reactive dye and the flame retardant in the present invention react with the fabric respectively, and the reactive dye and the flame retardant also react with each other, so that the formed flame retardant and the reactive dye are more stably combined with the fabric and have better durability. Specifically, ammonium polyphosphate is used as an example for explanation. The chlorine atoms in reactive red 120 and reactive blue 4 react with the hydroxyl groups in cellulose to form covalent bonds, the vinyl sulfone groups in reactive orange 16 react with the hydroxyl groups in cellulose to form COC, the ammonium polyphosphate reacts with cellulose to form a covalent bond POC, and the ammonium polyphosphate and the reactive dye undergo a substitution reaction to form a covalent bond.

[0020] Silane is hydrolyzed in ethanol or an ethanol / water mixed solution to form silanol groups (Si-OH), which then undergo condensation reactions with the hydroxyl groups on the fiber to form covalent bonds (Si-OC), introducing long-chain alkyl groups to the fiber surface, reducing its surface energy and making the fiber hydrophobic.

[0021] Therefore, in the durable flame retardant and hydrophobic dyed fabric finally obtained, flame retardants, dyes and hydrophobic agents are dispersed on the surface and inside of the fibers, and are difficult to separate from the fibers due to the covalent bond. The pre-treatment mercerization of cellulose fabrics reduces the crystallinity of the fabric, increases the amorphous area, and has more hydroxyl groups to react. Flame retardants can promote dyeing and fix color. Flame retardants react with dyes to form POC covalent bonds, which greatly enhances the degree of cross-linking, so that flame retardants, dyes and fibers are firmly combined together. Even after multiple washings, they still have good flame retardant effects and maintain bright colors. After hydrolysis, silane reacts with fibers to form covalent bonds and combines with the fiber surface. In general, covalent bonds combine flame retardants, dyes, hydrophobic agents and fiber fabrics together, providing them with durable flame retardant and hydrophobic dyeing functions.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) A one-pot durable flame retardant dyeing and finishing method was proposed. The flame retardant and dye molecules synergistically promoted each other to achieve the simultaneous durable flame retardancy and dyeing of cellulose fabrics. The finishing process was simple, the raw materials used were cheap and easily available, and the cost was low.

[0024] (2) The problem of formaldehyde-free and fluorine-free durable flame retardancy, hydrophobicity and simultaneous dyeing of cellulose fabrics and related cellulose textiles has been solved, and a flame retardant cellulose fabric that can withstand 500 washes has been obtained. The hydrophobic agent has an excellent hydrophobic effect and can protect the flame retardant and dye from contact with water, ensuring its durability. After multiple washes, it still has excellent flame retardant and hydrophobic effects while maintaining bright colors. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 These are photos of Example 3 after vertical combustion test and hydrophobicity after different water washing cycles.

[0026] Figure 2 This is the infrared spectrum of the cotton fabric (RR-APP-Cotton) after finishing in Comparative Example 2, the reactive dye (RR120) used, the flame retardant (APP) and the cotton fabric (Cotton).

[0027] Specific real-time method

[0028] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0029] Examples 1-6

[0030] (1) The cotton fabric is desized and mercerized. The pretreatment is to immerse the fabric in a 1 wt % NaOH solution at 100° C. for 1 hour and then dry it. The mercerization is to immerse the pretreated fabric in a 25 wt % NaOH solution for 6 minutes, then wash it to neutrality and put it in an oven for drying.

[0031] (2) The cotton fabric is immersed in a finishing liquid. After the immersion treatment, the excess liquid is squeezed out with a rolling wheel, and pre-curing and baking are performed in sequence. Then, the excess flame retardant and floating color are removed by washing with water, and the fabric is dried to obtain a durable flame retardant dyed fabric. The finishing liquid includes a flame retardant, dicyandiamide and a reactive dye. The amount and components of the finishing liquid and the process conditions of immersion, pre-curing and baking are specifically shown in Table 1.

[0032] (3) Adding hydrophobic silane to ethanol or ethanol / water mixed solution, then immersing the flame retardant dyed fabric in the hydrophobic solution and drying, thereby obtaining a durable flame retardant hydrophobic dyed fabric. The type, amount and immersion time of the silane are shown in Table 1.

[0033] Comparative Example 1

[0034] The cotton fabric is immersed in the finishing liquid, and after the immersion treatment (70°C, 35 minutes), the excess liquid is rolled out with a rolling car, and pre-curing and baking are carried out in sequence (pre-curing at 110°C, 25 minutes, baking at 170°C, 5 minutes), followed by washing to remove excess flame retardant and floating color, and drying to obtain a durable flame retardant dyed fabric or yarn, wherein the finishing liquid includes 190g / L low molecular weight ammonium polyphosphate, 40g / L dicyandiamide, and 2.5g / L reactive red 120.

[0035] Comparative Example 2

[0036] Compared with Comparative Example 1, this comparative example was pretreated and mercerized before finishing, specifically:

[0037] (1) Desizing and mercerizing the cotton fabric as in Example 1;

[0038] (2) The cotton fabric is immersed in the finishing liquid, and after the immersion treatment (70°C, 35 minutes), the excess liquid is rolled out with a rolling wheel, and pre-curing and baking are carried out in sequence (pre-curing at 110°C, 25 minutes, baking at 170°C, 5 minutes), followed by washing with water to remove excess flame retardant and floating color, and drying to obtain a durable flame retardant dyed fabric or yarn, wherein the finishing liquid comprises 190 g / L low molecular weight ammonium polyphosphate, 40 g / L dicyandiamide, and 2.5 g / L reactive red 120.

[0039] The infrared spectra of the finished cotton fabric (RR-APP-Cotton), the reactive dye (RR120), the flame retardant (APP) and the cotton fabric (Cotton) are shown in Figure 2. Figure 2 In the infrared spectrum, 3300 and 1023 cm -1 The characteristic peaks at 1023 cm-1 are attributed to -OH and COC in cellulose macromolecules. Compared with cotton fabric, the intensity of -OH peak of the finished cotton fabric is significantly reduced. This is because APP reacts with -OH of cotton fabric, and the resulting POC covalent bond appears at 1023 cm-1. -1 In the infrared spectrum of Reactive Red 120, the C-O-C bond of the pure cotton fabric is located at 618 cm -1 and 1044cm -1 The C-Cl bond did not appear in the finished cotton fabric, which proved that the C-Cl group of Reactive Red 120 reacted with cotton fiber and APP, and the dye, flame retardant and cotton fiber were successfully grafted.

[0040] Comparative Example 3

[0041] Compared with Comparative Example 1, this comparative example is subjected to hydrophobic treatment after finishing, specifically:

[0042] (1) The cotton fabric is immersed in a finishing liquid, and after the immersion treatment (70°C, 35 minutes), the excess liquid is rolled out with a rolling wheel, and pre-curing and baking are carried out in sequence (pre-curing at 110°C, 25 minutes, baking at 170°C, 5 minutes), followed by washing with water to remove excess flame retardant and floating color, and drying to obtain a durable flame retardant dyed fabric or yarn, wherein the finishing liquid comprises 190 g / L low molecular weight ammonium polyphosphate, 40 g / L dicyandiamide, and 2.5 g / L reactive red 120.

[0043] (2) adding a hydrophobic silane to ethanol or an ethanol / water mixed solution, and then immersing the flame retardant dyed fabric in the hydrophobic solution (at room temperature, 4 minutes), and drying, to obtain a durable flame retardant hydrophobic dyed fabric, wherein the silane is hexadecyltrimethoxysilane, and the specific amount used is 35 g / L.

[0044] The fabrics prepared in Comparative Examples 1-3 and Examples 1-6 were tested, and the vertical burning performance test was carried out according to the "Standard GB / T5455-2014", the limiting oxygen index test was carried out according to the "Standard GB / T 5454-1997", and the washing test was carried out according to the 1A standard in "AATCC 61-2013 ((E 2016)) Accelerated test for color fastness to washing for household and commercial use". The results are shown in Tables 1, 2 and Figure 1 .

[0045] The results show that compared with Comparative Example 1, Comparative Example 2 was pretreated, and the vertical combustion charcoal length was shorter and the limiting oxygen index was higher. After 100 water washings, compared with Comparative Example 1, the charcoal length was shorter and the limiting oxygen index decreased less, showing better flame retardancy and durability. Compared with Comparative Example 1, Comparative Example 3 was hydrophobic treated, and the vertical combustion and limiting oxygen indexes were closer, with slightly better effects. After water washing, the limiting oxygen index decreased less, and the charcoal length was shorter than that of Comparative Example 1, showing better flame retardancy and durability. Compared with Comparative Example 3, Comparative Example 2 has better effects after mercerization. The flame retardant properties of the fabrics of Examples 1-6 are significantly better than those of Comparative Example 2 after 100 water washings, and the decrease in flame retardant properties is still small after water washing 500 times, and the flame retardant properties show good durability. From Figure 1 As can be seen from the photos, the fabric still retains its bright color after 500 washes, with no noticeable fading.

[0046] Table 1

[0047]

[0048]

[0049]

[0050]

[0051] Table 2

[0052]

Claims

1. A durable flame retardant dyeing and finishing method for cellulose-based yarn or fabric, characterized in that: The following steps are involved: The cellulose-based yarn or fabric is immersed in a finishing liquid, and after dipping and rolling, it is pre-cured at 90-110°C, baked at 150-170°C, and then washed and dried to obtain a flame-retardant dyed fabric or yarn. The finishing liquid includes 150-250g / L flame retardant, 30-50g / L dicyandiamide, and 2.5-3.5g / L reactive dye. The flame retardant is one or more of ammonium phosphate, low molecular weight ammonium polyphosphate, and ammonium phytate. The reactive dye is one or more of reactive red 120, reactive orange 16, and reactive blue 4.

2. The durable flame retardant dyeing finishing method for cellulose-based yarn or fabric according to claim 1, characterized in that: The cellulose-based yarn is one or more blended yarns of cotton yarn, viscose yarn and lyocell yarn, and the cellulose-based fabric is a fabric corresponding to the cellulose-based yarn.

3. The durable flame retardant dyeing finishing method for cellulose-based yarn or fabric according to claim 1, characterized in that: The specific process of one dip and one roll is: immerse the cellulose-based yarn or fabric in the finishing liquid, keep it at 60-80℃ for 20-30min, and then use a roll car to roll out the excess liquid.

4. The durable flame retardant dyeing finishing method for cellulose-based yarn or fabric according to claim 1, characterized in that: After dipping and rolling, pre-curing is carried out at 90-110°C for 20-40 minutes and baking is carried out at 150-170°C for 4-6 minutes.

5. The durable flame retardant dyeing finishing method for cellulose-based yarn or fabric according to any one of claims 1 to 4, characterized in that: Desizing and mercerizing pretreatments are carried out before cellulose based yarns or fabrics are immersed in the finishing liquor.

6. The durable flame retardant dyeing finishing method for cellulose-based yarn or fabric according to claim 5, characterized in that: The cellulose-based yarn or fabric is subjected to hydrophobic finishing before being immersed in finishing liquid, and the durable flame-retardant dyed fabric or yarn is immersed in silane solution for finishing and dried to obtain the durable flame-retardant hydrophobic dyed fabric or yarn.

7. The durable flame retardant dyeing finishing method for cellulose-based yarn or fabric according to claim 6, characterized in that: The silane is one or more of vinyl triethoxysilane, methyl triethoxysilane, triethoxyoctylsilane, dodecyl trimethoxysilane, hexadecyl trimethoxysilane and octadecyl trimethoxysilane.

8. The durable flame retardant dyeing finishing method for cellulose-based yarn or fabric according to claim 6, characterized in that: The silane concentration in the silane solution is 10-50 g / L, and the finishing time in the silane solution is 2-5 min.

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