Flame-retardant silk fabric, preparation method and application thereof

Abstract

The present invention provides a flame-retardant silk fabric and its preparation method and application, belonging to the field of textile finishing technology. The present invention uses pyrazolyl borate as a flame retardant. The borate structure therein forms a glassy molten covering during combustion, improving the stability of the carbon layer and achieving a flame retardant effect. Furthermore, the nitrogen-containing component in the flame retardant produces difficult-to-combust gases such as ammonia and nitrogen during combustion, which can dilute the concentration of the combustible gas and act as a foaming agent for the carbon layer to form a foamed, expanded porous carbon layer, restricting the entry of combustible gases into the gas phase to achieve heat insulation and oxygen isolation. The boron-nitrogen synergistic effect enables the compound of formula II to effectively improve the flame retardant properties of silk, while also improving the mechanical properties of the silk fabric, and substantially having no adverse effect on its softness and smoothness.

Description

Technical Field

[0001] The present invention relates to the technical field of textile finishing, in particular to a flame-retardant silk fabric and a preparation method and application thereof. Background Art

[0002] Silk, a natural protein fiber, boasts an elegant luster, comfort, excellent moisture absorption and permeability, and softness, making it widely used in clothing, curtains, bedding, and other applications. However, silk fabrics have a limiting oxygen index of approximately 23%, making them flammable. Combustion produces large amounts of toxic substances such as CO and HCN. Therefore, flame-retardant finishing of silk fabrics not only expands their applications but also plays a significant role in protecting people's lives and property.

[0003] Existing technologies use halogen-based flame retardants to improve the flame retardancy of silk. However, these agents release toxic and corrosive hydrogen halide gases during combustion, severely polluting the environment and endangering human health. With growing environmental awareness, research on flame retardants is increasingly focused on green, environmentally friendly, and efficient methods. Halogen-free phosphorus-based flame retardants are attracting increasing attention, but they pose challenges such as high flame retardant dosages and poor physical properties of finished silk fabrics. Furthermore, the production and use of phosphorus-based flame retardants generates large amounts of phosphorus-containing wastewater, impacting the ecological environment.

[0004] Therefore, how to improve the flame retardant properties of silk fabrics while ensuring their physical properties has become a difficult problem in the existing technology. Summary of the Invention

[0005] The present invention aims to provide a flame-retardant silk fabric, a preparation method thereof, and an application thereof. The silk fabric prepared by the preparation method provided by the present invention has excellent flame retardant properties, while also improving the mechanical strength of the silk fabric and maintaining the softness and smoothness of the silk fabric.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a flame-retardant silk fabric, comprising the following steps:

[0008] (1) mixing pyrazolyl borate and a solvent to obtain a flame retardant finishing liquid;

[0009] The structure of the pyrazolyl borate is shown in Formula I or Formula II:

[0010]

[0011] (2) The silk fabric is shaken in the flame retardant finishing liquid obtained in step (1) to obtain a flame retardant silk fabric.

[0012] Preferably, the solvent in step (1) is a mixed solution of ethanol and water.

[0013] Preferably, the volume ratio of ethanol to water is 1:(2.5-4).

[0014] Preferably, the concentration of pyrazolyl borate in the flame retardant finishing liquid in step (1) is 0.05 to 0.25 mol / L.

[0015] Preferably, in step (2), the mass ratio of the silk fabric to the pyrazolyl borate in the flame retardant finishing liquid is 1:(0.6-4.5).

[0016] Preferably, the oscillation temperature in step (2) is 40 to 80° C., and the oscillation time is 2 to 12 hours.

[0017] Preferably, after the oscillation in step (2) is completed, washing and drying are also performed in sequence.

[0018] Preferably, the drying temperature is 40-80° C., and the drying time is 2-10 hours.

[0019] The present invention provides a flame-retardant silk fabric prepared by the preparation method described in the above technical solution.

[0020] The present invention also provides the use of the flame-retardant silk fabric described in the above technical solution in clothing, curtains and bedding.

[0021] The present invention provides a method for preparing a flame-retardant silk fabric, comprising the following steps: (1) mixing a pyrazolyl borate and a solvent to obtain a flame-retardant finishing liquid; the structure of the pyrazolyl borate is as shown in Formula I or Formula II:

[0022]

[0023] (2) The silk fabric is shaken in the flame retardant finishing liquid obtained in step (1) to obtain a flame retardant silk fabric. The present invention uses pyrazolyl borate as a flame retardant, wherein the borate structure forms a glassy molten covering during the combustion process, thereby improving the stability of the carbon layer and achieving a flame retardant effect. Furthermore, the nitrogen-containing component in the flame retardant produces incombustible gases such as ammonia and nitrogen during the combustion process, which can dilute the concentration of the combustible gas and serve as a foaming agent for the carbon layer to form a foamed, expanded porous carbon layer, which restricts the combustible gas from entering the gas phase to achieve heat insulation and oxygen isolation. The boron-nitrogen synergistic effect enables the compound of formula II to effectively improve the flame retardant properties of silk, while also improving the mechanical properties of the silk fabric without adversely affecting its softness and smoothness. The results of the examples show that the limiting oxygen index of the flame retardant silk fabric prepared by the preparation method of the present application is above 25.8%, which is a flame retardant product. At the same time, the mechanical strength of the silk fabric is improved, and the softness and smoothness of the silk fabric remain basically unchanged. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The infrared spectra of the compound of formula I, the compound of formula II, the flame retardant silk fabrics of Examples 1 and 2, and the silk fabric of Comparative Example 1 are shown;

[0025] Figure 2 This is a SEM image of the carbon residue of the silk fabric after vertical combustion in Comparative Example 1 of the present invention;

[0026] Figure 3 This is a SEM image of the carbon residue after vertical combustion of the flame-retardant silk fabric of Example 1 of the present invention;

[0027] Figure 4 This is a SEM image of the carbon residue after vertical combustion of the flame-retardant silk fabric of Example 2 of the present invention;

[0028] Figure 5 1 and 2. These are stress-strain curves of the flame-retardant silk fabrics of Examples 1 and 2 of the present invention and the silk fabric of Comparative Example 1. DETAILED DESCRIPTION

[0029] The present invention provides a method for preparing a flame-retardant silk fabric, comprising the following steps:

[0030] (1) mixing pyrazolyl borate and a solvent to obtain a flame retardant finishing liquid;

[0031] The structure of the pyrazolyl borate is shown in Formula I or Formula II:

[0032]

[0033] (2) The silk fabric is shaken in the flame retardant finishing liquid obtained in step (1) to obtain a flame retardant silk fabric.

[0034] Unless otherwise specified, the present invention has no special limitation on the sources of the raw materials, and commercially available products familiar to those skilled in the art can be used. In an embodiment of the present invention, the compound of formula I is preferably purchased from Anaiji; the compound of formula II is preferably synthesized according to the steps described in the document [Organic Letters, 2020, 22(24): 9408-9414.], specifically: 12.6g 1-methyl-1H-pyrazole-4-boric acid, 17.6g N-methyliminodiacetic acid, 60mL toluene and 30mL dimethyl sulfoxide are added to a 250mL reaction flask and heated under reflux for 6h. After the reaction is completed, the temperature is cooled to room temperature, and the solvent is removed by distillation under reduced pressure to obtain an oily mixture, which is then recrystallized from water to obtain 12.3g of white solid, i.e., the compound of formula II, and its specific reaction equation is as follows:

[0035]

[0036] The invention mixes pyrazolyl borate and a solvent to obtain a flame retardant finishing liquid.

[0037] In the present invention, the structure of the pyrazolyl borate is shown in Formula I or Formula II:

[0038]

[0039] In the present invention, the pyrazolyl borate is used as a flame retardant, and the borate structure therein forms a glassy molten covering during the combustion process, thereby improving the stability of the carbon layer and achieving a flame retardant effect. Furthermore, the nitrogen-containing component in the flame retardant will produce inflammable gases such as ammonia and nitrogen during the combustion process, which can dilute the concentration of the combustible gas and serve as a foaming agent for the carbon layer to form a foamed, expanded porous carbon layer, which restricts the combustible gas from entering the gas phase to achieve heat insulation and oxygen isolation. The synergistic effect of boron and nitrogen enables the compound of formula II to effectively improve the flame retardant properties of silk, while also improving the mechanical properties of silk fabrics without adversely affecting their softness and smoothness. Compared with halogen-based and phosphorus-based flame retardants, the flame retardant of the present invention is less toxic and more environmentally friendly.

[0040] In the present invention, the solvent is preferably a mixed solution of ethanol and water; the volume ratio of ethanol to water is preferably 1:(2.5-4), more preferably 1:(2.5-3). The present invention limits the composition of the solvent and the amount of each component to the above range, which can enable the flame retardant to be better absorbed by the silk.

[0041] In the present invention, the concentration of pyrazolyl borate in the flame retardant finishing liquid is preferably 0.05-0.25 mol / L, more preferably 0.15-0.25 mol / L. By limiting the concentration of pyrazolyl borate in the flame retardant finishing liquid to the above range, the present invention can more fully dissolve the pyrazolyl borate.

[0042] The present invention has no particular limitation on the operation of mixing the pyrazolyl borate and the solvent, and a technical solution for mixing materials well known to those skilled in the art can be used.

[0043] After obtaining the flame retardant finishing liquid, the present invention oscillates the silk fabric in the flame retardant finishing liquid to obtain the flame retardant silk fabric.

[0044] In the present invention, the silk fabric is preferably a plain crepe satin silk fiber fabric.

[0045] In the present invention, the mass ratio of the silk fabric to the pyrazolyl borate in the flame-retardant finishing liquid is preferably 1:(0.6-4.5), more preferably 1:(1.0-4.5), and even more preferably 1:(2.0-4.5). By limiting the mass ratio of the silk fabric to the pyrazolyl borate in the flame-retardant finishing liquid to the above range, the silk fabric can absorb more pyrazolyl borate flame retardant, further improving its flame retardant properties and mechanical properties without adversely affecting its softness and smoothness.

[0046] In the present invention, the oscillation temperature is preferably 40-80°C, more preferably 50-60°C; the oscillation time is preferably 2-12 hours, more preferably 6-7 hours; and the oscillation frequency is preferably 150 RPM. By limiting the oscillation temperature and time to the aforementioned ranges, the present invention enables the silk fabric to absorb more pyrazolyl borate flame retardant.

[0047] After the shaking is completed, the present invention also preferably sequentially washes and dries the shaken fabric.

[0048] The present invention has no special limitation on the water washing operation, and the flame retardant finishing liquid can be cleaned by using a water washing technical solution well known to those skilled in the art.

[0049] In the present invention, the drying temperature is preferably 40 to 80° C., more preferably 60 to 70° C.; the drying time is preferably 2 to 10 hours, more preferably 3 to 4 hours.

[0050] The present invention adopts pyrazolyl borate as a flame retardant, which not only improves the flame retardancy of silk, but also improves its mechanical properties without affecting its softness and smoothness.

[0051] The present invention provides a flame-retardant silk fabric obtained by the preparation method described in the above technical solution.

[0052] The flame-retardant silk fabric prepared by the invention has excellent flame-retardant performance, mechanical properties, softness and smoothness.

[0053] The present invention also provides the use of the flame-retardant silk fabric described in the above technical solution in clothing, curtains and bedding.

[0054] The present invention has no special limitation on the application of the flame-retardant silk fabric in clothing, curtains and beddings, and the technical solutions for the application of the flame-retardant silk fabric in clothing, curtains and beddings well known to those skilled in the art can be adopted.

[0055] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0056] Example 1

[0057] (1) 2.9630 g of pyrazolyl borate was dissolved in 50 mL of a mixed solution of ethanol and water, with the volume ratio of ethanol to water being 1:2.5, to obtain a flame retardant finishing liquid. The concentration of pyrazolyl borate in the flame retardant finishing liquid was 0.25 mol / L. The structure of pyrazolyl borate is shown in Formula II:

[0058]

[0059] (2) A plain crepe silk fabric (8.9 × 30 cm) was immersed in the flame retardant finishing solution (the mass ratio of the silk fabric to the pyrazolyl borate in the flame retardant finishing solution was 1:4.4), and the fabric was oscillated at a constant temperature of 50 ° C for 7 h (the oscillation frequency was 150 RPM). The silk fabric was taken out, washed three times with water, and dried at 60 ° C for 3 h to obtain a flame retardant silk fabric.

[0060] Example 2

[0061] (1) 2.601 g of pyrazolyl borate was dissolved in 50 mL of a mixed solution of ethanol and water, with the volume ratio of ethanol to water being 1:2.5, to obtain a flame retardant finishing liquid. The concentration of pyrazolyl borate in the flame retardant finishing liquid was 0.25 mol / L. The structure of pyrazolyl borate is shown in Formula I:

[0062]

[0063] (2) A plain crepe silk fabric (8.9×30 cm) was immersed in the above-mentioned flame retardant finishing liquid (the mass ratio of the silk fabric to the pyrazolyl borate in the flame retardant finishing liquid was 1:3.9), and the fabric was oscillated at a constant temperature of 50°C for 7 h (the oscillation frequency was 150 RPM). The silk fabric was taken out, washed three times with water, and dried at 60°C for 3 h to obtain a flame retardant silk fabric.

[0064] Example 3

[0065] The amount of pyrazolyl borate in Example 1 was replaced with 0.5926 g. At this time, the concentration of pyrazolyl borate in the flame retardant finishing liquid was 0.05 mol / L. The mass ratio of pyrazolyl borate in the silk fabric and the flame retardant finishing liquid was 1:0.9. Other parameters were the same as in Example 1.

[0066] Example 4

[0067] The amount of pyrazolyl borate in Example 1 was replaced with 1.7778 g. At this time, the concentration of pyrazolyl borate in the flame retardant finishing liquid was 0.15 mol / L. The mass ratio of pyrazolyl borate in the silk fabric and the flame retardant finishing liquid was 1:2.7. Other parameters were the same as in Example 1.

[0068] Comparative Example 1

[0069] Untreated plain crepe silk fabric.

[0070] The limiting oxygen index (LOI) of the flame retardant silk fabrics of Examples 1 to 4 and the silk fabric of Comparative Example 1 was tested according to GB / T 5455-2014 “Oxygen Index Method for Textile Combustion Performance Tests”. The results are shown in Table 1.

[0071] Table 1 Limiting oxygen index of silk fabrics in Examples 1 to 4 and Comparative Example 1

[0072] LOI / % Comparative Example 1 24.2 Example 1 28.3 Example 2 27.5 Example 3 25.8 Example 4 26.1

[0073] As can be seen from Table 1, after treatment with the flame retardant of the present invention, the limiting oxygen index of the silk fabric is increased from 24.2% to more than 25.8%, and can reach a maximum of 28.3%, which is a flame retardant product and improves the flame retardant properties of the silk fabric. At the same time, compared with the compound of formula I, the silk fabric treated with the compound of formula II has better flame retardant properties.

[0074] The infrared spectra of the compound of formula I, the compound of formula II, the flame retardant silk fabrics of Examples 1-2 and the silk fabric of Comparative Example 1 are as follows: Figure 1 As shown. Figure 1 It can be seen from the infrared spectra of Example 1 and Example 2 that the infrared spectra at 1384 cm -1 There is an absorption peak near the stretching vibration peak of the BO bond. Example 2 is at 1742 cm -1 There is a C=O absorption peak near 1233 cm -1 The absorption of the CN bond characteristic peak at the position is enhanced, indicating that the flame retardant is successfully grafted onto the silk fabric.

[0075] The SEM images of the carbon residues after vertical combustion of the silk fabric of Comparative Example 1 and the flame-retardant silk fabric of Examples 1 and 2 are shown as follows: Figures 2-4 As shown. Figures 2-4 It can be seen that the slag surface of the silk fabric is broken and incomplete, while complete holes with thin films appear on the surface of the carbon layer of Example 1 and Example 2, forming a typical expansion barrier carbon layer, which can protect the silk fabric from further burning.

[0076] The stress-strain curves of the flame-retardant silk fabrics of Examples 1 and 2 and the silk fabric of Comparative Example 1 are as follows: Figure 5 The data of tensile stress and elongation at break are shown in Table 2.

[0077] Table 2 Tensile stress and elongation at break of silk fabrics in Examples 1-2 and Comparative Example 1

[0078] Sample Tensile stress (cN) Elongation at break (%) Comparative Example 1 86.8±0.63 26.78±1.89 Example 1 100.29±6.87 28.09±1.75 Example 2 109.81±5.55 30.49±2.85

[0079] from Figure 5 As can be seen from Table 2, the tensile strength of the untreated silk fiber of Comparative Example 1 is 86.80 cN, and the elongation at break is 26.78%. Compared with the untreated silk fiber, the mechanical strength of the silk fiber is significantly enhanced after the introduction of pyrazolyl borate. The elongations at break of Example 1 and Example 2 are 28.09% and 30.49%, respectively, and the tensile strength is increased by 15.54% and 26.51%, respectively, indicating that pyrazolyl borate can effectively improve the mechanical strength of silk.

[0080] The softness and smoothness of the flame-retardant silk fabrics of Examples 1-2 and the silk fabric of Comparative Example 1 were tested, and the results are shown in Table 3.

[0081] Table 3 Softness and smoothness of flame-retardant silk fabrics of Examples 1-2 and silk fabric of Comparative Example 1

[0082] Sample Softness Smoothness Comparative Example 1 97.77±0.77 61.00±0.23 Example 1 94.14±1.13 56.23±0.24 Example 2 95.66±0.81 58.31±0.37

[0083] As can be seen from Table 3, the smoothness and softness of the silk fabric treated with pyrazolyl borate flame retardant are not much different from those of the untreated silk fabric.

[0084] In summary, silk fabrics flame-retardantly treated with pyrazolyl borate have good flame retardant properties and mechanical properties, and have little effect on the smoothness and softness of the silk fabrics.

[0085] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a flame-retardant silk fabric, comprising the following steps: (1) mixing pyrazolyl borate and a solvent to obtain a flame retardant finishing liquid; The structure of the pyrazolyl borate is shown in Formula II: (2) Oscillating the silk fabric in the flame retardant finishing liquid obtained in step (1) to obtain a flame retardant silk fabric.

2. The preparation method according to claim 1, characterized in that The solvent in step (1) is a mixed solution of ethanol and water.

3. The preparation method according to claim 2, characterized in that The volume ratio of the ethanol to water is 1:(2.5-4).

4. The preparation method according to claim 1, characterized in that The concentration of pyrazolyl borate in the flame retardant finishing liquid in step (1) is 0.05-0.25 mol / L.

5. The preparation method according to claim 1, characterized in that In the step (2), the mass ratio of the silk fabric to the pyrazolyl borate in the flame retardant finishing liquid is 1:(0.6-4.5).

6. The preparation method according to claim 1, characterized in that The oscillation temperature in the step (2) is 40 to 80° C., and the oscillation time is 2 to 12 hours.

7. The preparation method according to claim 1, characterized in that After the oscillation in step (2) is completed, the process further includes washing with water and drying.

8. The preparation method according to claim 7, characterized in that The drying temperature is 40-80° C., and the drying time is 2-10 hours.

9. The flame-retardant silk fabric prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the flame-retardant silk fabric according to claim 9 in clothing, curtains and bedding.

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