Preparation method of polyester / cotton blended fabric with polyphosphoramide durable flame retardant coating and polyester / cotton blended fabric

Abstract

The present invention provides a method for preparing a polyester / cotton blended fabric with a polyphosphoramide durable flame retardant coating and the polyester / cotton blended fabric. The method comprises: using phosphorus oxychloride and ethylenediamine to react at a certain temperature for a certain time to prepare an amino-terminated branched polyphosphoramide flame retardant. First, the polyester / cotton blended fabric is pretreated with cyanuric chloride to obtain a pretreated polyester / cotton blended fabric; then, the pretreated polyester / cotton blended fabric is treated with an amino-terminated branched polyphosphoramide flame retardant; finally, the treated polyester / cotton blended fabric is treated with a sodium alginate solution to obtain a flame retardant coated polyester / cotton blended fabric. The preparation method of the present invention is simple, and the polyester / cotton blended fabric prepared by the method has excellent flame retardant and water washability.

Description

Technical Field

[0001] The invention belongs to the technical field of textile function modification, and relates to a preparation method of a polyester / cotton blended fabric with a polyphosphoramide durable flame retardant coating and the polyester / cotton blended fabric. Background Art

[0002] Polyester / cotton blended fabrics have a broad application market and occupy an important position in the modern textile industry. However, polyester / cotton blended fabrics are flammable materials, and the two components also have a "wick effect", making flame retardant modification relatively difficult. There are still great challenges in developing efficient and durable flame retardant polyester / cotton blended fabrics.

[0003] With the increasing requirements for ecological and environmental protection, most halogen flame retardants are banned. Phosphorus-containing flame retardants for textiles have been greatly developed. References (Wang Fei, Xu Yanhua, Mao Anqi, et al. Application of new flame retardants in polyester-cotton blended fabrics [J]. Dyeing and Finishing Technology, 2021, 43(10): 25-28) The polyester / cotton blended fabric was flame-retardant modified using polyester flame retardant and cotton flame retardant / cross-linking agent system. The modified polyester / cotton blended fabric can withstand 20 washes, but the flame retardant modification releases formaldehyde.

[0004] Branched phosphoramide flame retardants are a type of dendritic compounds with a special structure. They have a large amount of phosphorus and nitrogen content and reactive end groups. They have high flame retardant efficiency, are halogen-free and environmentally friendly, and have attracted widespread attention from researchers. References (Wang Yanlin, Wang Dongjun, Zong Fengjuan, et al. Synthesis of intumescent flame retardant neopentyl glycol ethylene phosphoramide [J]. Plastic Additives, 2009 (3): 29-31.) Neopentyl glycol is reacted with phosphorus oxychloride to obtain neopentyl glycol ethylene phosphoramide, which is then reacted with ethylenediamine to obtain neopentyl glycol ethylene phosphoramide. However, the flame retardant has low phosphorus and nitrogen content, low flame retardant efficiency, and cannot form a strong bond with polyester / cotton blended fabrics.

[0005] References (Zhang Chao, Jiang Zhiming, Zhu Shaotong, et al. Application of hyperbranched phosphoramide in flame retardant finishing of viscose fabrics [J]. Journal of Textile Research, 2021, 42(7): 39-45.) Polyhydroxy hyperbranched phosphoramide was synthesized using trichlorophosphorus and diethanolamine as raw materials, and the flame retardant finishing system was made of polyhydroxy hyperbranched phosphoramide and 1,2,3,4-butanetetracarboxylic acid crosslinking agent, which improved the water washing resistance of flame retardant viscose; the system has high flame retardant efficiency, and polycarboxylic acid can be used as a crosslinking agent to crosslink with viscose fabrics containing active hydroxyl groups, but it causes severe damage to viscose fabrics. Polyhydroxy hyperbranched phosphoramide is easily soluble in water and gradually dissolves in the detergent during the washing process. The water washing resistance of flame retardant viscose fabrics still needs to be further improved.

[0006] In addition, there are fewer cotton components and active groups in polyester / cotton blended fabrics, making it difficult to fix a sufficient amount of branched phosphoramide flame retardants on polyester / cotton blended fabrics by crosslinking with a crosslinking agent. Therefore, there is a great challenge in how to develop more efficient phosphoramide flame retardants and use them for the durable flame retardant and antibacterial multifunctional modification of polyester / cotton blended fabrics.

[0007] Therefore, it is necessary to provide a new technical solution. Summary of the invention

[0008] In order to solve the above technical problems and overcome the shortcomings of the prior art, the present invention provides a method for preparing a polyester / cotton blended fabric with a polyphosphoramide durable flame retardant coating and a polyester / cotton blended fabric. The preparation method is simple, and the prepared polyester / cotton blended fabric has excellent flame retardant and water washability.

[0009] In order to achieve the above purpose, the following technical solutions are adopted:

[0010] In one aspect, the present invention provides a method for preparing a polyester / cotton blended fabric with a polyphosphoramide durable flame retardant coating, which comprises the following steps:

[0011] (1) reacting a dichloromethane solution containing phosphorus oxychloride and a dichloromethane solution containing ethylenediamine at a certain temperature for a certain period of time to obtain an amino-terminated branched polyphosphoramide flame retardant;

[0012] (2) Pretreating the polyester / cotton blended fabric with a cyanuric chloride solution to obtain a pretreated polyester / cotton blended fabric;

[0013] (3) treating the pretreated polyester / cotton blended fabric with an amino-terminated branched polyphosphoramide flame retardant;

[0014] (4) The polyester / cotton blended fabric treated in step (3) is treated with a sodium alginate solution to obtain a flame retardant coated polyester / cotton blended fabric.

[0015] Furthermore, in step (1), the mass ratio of phosphorus oxychloride to dichloromethane is 1:10-20, the mass ratio of ethylenediamine to dichloromethane is 1:10-20, and the molar ratio of phosphorus oxychloride to ethylenediamine is 1:2.5-3.

[0016] Furthermore, step (1) specifically includes:

[0017] (11) Under nitrogen protection, slowly add the dichloromethane solution of phosphorus oxychloride to the chloroform solution of ethylenediamine at a rate of 3-5 ml / min, react at 0-5 °C for 2-3 h, and then continue to react at 40-50 °C for 5-6 h;

[0018] (12) The product of the reaction in step (11) is subjected to reduced pressure distillation, washed with ethanol, and dried to obtain an amino-terminated branched polyphosphoramide flame retardant.

[0019] Furthermore, step (2) specifically includes:

[0020] (21) The pH value of the aqueous solution is adjusted to 9-10 using sodium carbonate, and cyanuric chloride is added to the aqueous solution to obtain a cyanuric chloride solution, wherein the amount of cyanuric chloride used is 20-30 g / L.

[0021] (22) Immerse the polyester / cotton blended fabric in a cyanuric chloride solution and perform padding at room temperature for 10 minutes;

[0022] (23) Drying the impregnated polyester / cotton blended fabric in step (22) to obtain a pretreated polyester / cotton blended fabric, wherein the drying temperature is 60-80° C. and the drying time is 2-4 min.

[0023] Furthermore, step (3) specifically includes:

[0024] (31) Immersing the pretreated polyester / cotton blended fabric in an amino-terminated branched polyphosphoramide flame retardant and padding the fabric within 10 minutes at room temperature, wherein the amount of the amino-terminated branched polyphosphoramide flame retardant is 30-50 g / L;

[0025] (32) Drying the polyester / cotton blended fabric treated in step (31), wherein the drying temperature is 60-80° C. and the drying time is 3-5 min.

[0026] Furthermore, step (4) specifically includes:

[0027] (41) Dissolving sodium alginate in distilled water to prepare a sodium alginate solution, wherein the amount of sodium alginate is 20-30 g / L;

[0028] (42) immersing the polyester / cotton blended fabric obtained in step (3) in a sodium alginate solution and performing padding at room temperature for 10 minutes;

[0029] (43) Drying the polyester / cotton blended fabric after the padding in step (42) to obtain a flame retardant coated polyester / cotton blended fabric, wherein the drying temperature is 60-80° C. and the drying time is 3-5 min.

[0030] Furthermore, the method further comprises: repeating steps (2) to (4) 2 to 4 times.

[0031] The polyester / cotton blended fabric is one of 80 / 20 polyester / cotton blended fabric, 65 / 35 polyester / cotton blended fabric and 50 / 50 polyester / cotton blended fabric.

[0032] In another aspect, the present invention further provides a polyester fabric, which is prepared by the above method.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] (1) In the present invention, the active chlorine of phosphorus oxychloride and the amino group of ethylenediamine can react to form phosphoramide, and the molar ratio between the two is controlled to synthesize amino-terminated branched polyphosphoramide. The flame retardant is rich in phosphorus and nitrogen elements and has high flame retardant efficiency.

[0035] (2) Although amino-terminated branched polyphosphoramide contains a large number of active amino groups, the active groups on the polyester / cotton blended fabric are limited. It is impossible to firmly fix the amino-terminated branched polyphosphoramide on the polyester / cotton blended fabric by relying solely on the cross-linking effect of cyanuric chloride. In addition, amino-terminated branched polyphosphoramide is easily soluble in water, resulting in poor flame retardancy and durability.

[0036] The present invention deposits amino-terminated branched polyphosphoramide, cyanuric chloride and sodium alginate on a polyester / cotton blended fabric in sequence. Under the action of temperature, the active amino groups of the amino-terminated branched polyphosphoramide, the hydroxyl groups of the sodium alginate and the active chlorine of the cyanuric chloride undergo affinity substitution reactions. On the one hand, cyanuric chloride, as a network crosslinking agent, causes crosslinking between the branches of the amino-terminated branched polyphosphoramide, and the sodium alginate and the amino-terminated branched polyphosphoramide undergo ionic bonding, so that the amino-terminated branched polyphosphoramide forms a flame retardant film with high adhesion and poor water solubility on the surface of the polyester / cotton blended fabric; on the other hand, the covalent crosslinking generated by cyanuric chloride and cotton fibers can further improve the fixation of the flame retardant film on the fabric surface. The amino-terminated branched polyphosphoramide flame retardant, cyanuric chloride and sodium alginate undergo crosslinking on the surface of the polyester / cotton blended fabric and produce a self-deposition coating, thereby giving the coated polyester / cotton blended fabric a durable flame retardant function.

[0037] (3) The amino-terminated branched polyphosphoramide molecules are rich in phosphorus and nitrogen elements, which can form a phosphorus / nitrogen synergistic flame retardant effect. In addition to being a network cross-linking agent, cyanuric chloride can also provide triazine rings and has high carbon-forming properties. Sodium alginate is a good carbon-forming agent. It can construct an intumescent flame retardant system with the amino-terminated branched polyphosphoramide flame retardant and has good expansion and foaming properties during the combustion process. Therefore, the amino-terminated branched polyphosphoramide, cyanuric chloride and sodium alginate self-deposition coating mainly improves the flame retardant properties of polyester / cotton blended fabrics through the expansion flame retardant mechanism, and has high flame retardant efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 The amino-terminated branched polyphosphoramide of the present invention 1 H NMR spectrum. DETAILED DESCRIPTION

[0040] To further help understand the technical solution of the present invention, the technical solution of the present invention is described in more detail below by providing several specific implementation examples. All of the described embodiments are only partial embodiments of the present invention, not all of them. The following specific embodiments may be combined with each other, and the same or similar concepts or processes therein may not be repeated in some embodiments.

[0041] The invention discloses a method for preparing a polyester / cotton blended fabric with a polyphosphoramide durable flame retardant coating. The method comprises the following steps: firstly, phosphorus oxychloride and ethylenediamine are used to synthesize amino-terminated branched polyphosphoramide, and then cyanuric chloride and amino-terminated branched polyphosphoramide are used to treat the polyester / cotton blended fabric respectively, so as to prepare the polyester / cotton blended fabric with a durable flame retardant coating.

[0042] The following examples describe the preparation method of polyphosphoramide durable flame retardant coated polyester / cotton blended fabric, and the performance of the modified polyester / cotton blended fabric and the unmodified polyester / cotton blended fabric prepared in the examples of the present application are tested.

[0043] Test standard:

[0044] The damage length of modified polyester / cotton blended fabrics and unmodified polyester / cotton blended fabrics is measured in accordance with GB / T 5455-2014 "Determination of the damage length in the vertical direction, smoldering and afterflaming time of textile combustion performance".

[0045] The limiting oxygen index (LOI) of modified polyester / cotton blended fabrics and unmodified polyester / cotton blended fabrics was tested in accordance with GB / T 5454-1997 "Oxygen Index Method for Textile Combustion Performance Test".

[0046] Example 1

[0047] The present invention provides a method for preparing a durable flame-retardant and antibacterial multifunctional coated polyester fabric, comprising the following steps:

[0048] (1) A dichloromethane solution containing phosphorus oxychloride and a dichloromethane solution containing ethylenediamine are reacted at a certain temperature for a certain time to obtain an amino-terminated branched polyphosphoramide flame retardant. In step (1), the mass ratio of phosphorus oxychloride to dichloromethane is 1:15, the mass ratio of ethylenediamine to dichloromethane is 1:15, and the molar ratio of phosphorus oxychloride to ethylenediamine is 1:2.9. Theoretically, phosphorus oxychloride reacts with ethylenediamine to generate a phosphoramide structure. Excessive ethylenediamine can act as an acid-binding agent and catalyst, which helps to promote the reaction and helps to ensure the generation of a branched polyphosphoramide structure with an amino end group.

[0049] Step (1) specifically comprises: under nitrogen protection, slowly adding a dichloromethane solution of phosphorus oxychloride to a trichloromethane solution of ethylenediamine at a rate of 5 ml / min, reacting at 4°C for 2.4 hours, and then continuing to react at 45°C for 5.5 hours; the first active chlorine of phosphorus oxychloride has a low reaction temperature, and the remaining active chlorine needs to react at room temperature or higher temperature, and finally, after reduced pressure distillation, ethanol washing, and drying, the amino-terminated branched polyphosphoramide is obtained. Please refer to Figure 1 , which is the 1H nuclear magnetic resonance spectrum of the amino-terminated branched polyphosphoramide of the present invention. Figure 1 As shown, in the 1H NMR spectrum, the absorption peak at 4.7ppm is the solvent peak of heavy water, the absorption peak at 2.9ppm is the proton peak of ethylenediamine methylene in the amino-terminated branched polyphosphoramide molecule, and the absorption peak at 2.0ppm is the terminal amino peak. The above results indicate that the amino-terminated branched polyphosphoramide was successfully synthesized.

[0050] The above reactions were all carried out under nitrogen protection by slowly introducing nitrogen into the reaction vessel. The yield of amino-terminated branched polyphosphoramide was 78% and the weight average molecular weight was 1950.

[0051] (2) Pre-treating a polyester / cotton blended fabric with a cyanuric chloride solution to obtain a pre-treated polyester / cotton blended fabric. In this embodiment, the polyester / cotton blended fabric used is a 65 / 35 polyester / cotton blended fabric. This step (2) specifically includes:

[0052] (21) The pH value of the aqueous solution is adjusted to 10 using sodium carbonate, and cyanuric chloride is added to the aqueous solution to obtain a cyanuric chloride solution, wherein the amount of cyanuric chloride used is 27 g / L. The pH value of the aqueous solution is adjusted using sodium carbonate so that the cyanuric chloride is uniformly dispersed in the aqueous solution. Sodium carbonate acts as an acid binding agent and catalyst to promote the reaction between cyanuric chloride and cotton fibers.

[0053] (22) The polyester / cotton blended fabric was immersed in a cyanuric chloride solution and rolled at room temperature for 10 minutes. The rolling rate was 97%. The higher the rolling rate, the higher the amount of liquid and flame retardant in the polyester / cotton blended fabric, and the better the flame retardant effect. However, if the rolling rate is too high, it will easily lead to unevenness.

[0054] (23) Drying the impregnated polyester / cotton blended fabric in step (22) to obtain a pretreated polyester / cotton blended fabric, wherein the drying temperature is 70° C. and the drying time is 3 min.

[0055] (3) The pretreated polyester / cotton blended fabric is treated with an amino-terminated branched polyphosphoramide flame retardant.

[0056] Step (3) specifically includes:

[0057] (31) The pretreated polyester / cotton blended fabric was immersed in an amino-terminated branched polyphosphoramide flame retardant and padding was performed within 10 minutes at room temperature, wherein the amount of the amino-terminated branched polyphosphoramide flame retardant was 45 g / L; a high amount of the amino-terminated branched polyphosphoramide was helpful to improve the flame retardant properties of the polyester / cotton blended fabric, but too high an amount would easily lead to uneven coating. The padding rate was 97%, and the higher the padding rate, the higher the amount of liquid and flame retardant in the polyester / cotton blended fabric, and the better the flame retardant effect, but too high an amount would easily lead to uneven coating.

[0058] (32) Drying the polyester / cotton blended fabric treated in step (31), wherein the drying temperature is 70° C. and the drying time is 4 min.

[0059] (4) The polyester / cotton blended fabric treated in step (3) is treated with a sodium alginate solution to obtain a flame retardant coated polyester / cotton blended fabric. Step (4) specifically comprises:

[0060] (41) Sodium alginate solution was prepared by dissolving sodium alginate in distilled water, wherein the amount of sodium alginate was 27 g / L. A high amount of sodium alginate helps to improve the flame retardant properties of polyester / cotton blended fabrics, but too high an amount can easily lead to uneven coating.

[0061] (42) The polyester / cotton blended fabric treated in step (3) is immersed in a sodium alginate solution and rolled at room temperature for 10 minutes; the rolling rate is 97%. The higher the rolling rate, the higher the amount of liquid and flame retardant in the polyester / cotton blended fabric, and the better the flame retardant effect. However, if the rolling rate is too high, it will easily lead to unevenness.

[0062] (43) Drying the polyester / cotton blended fabric after the padding in step (42) to obtain a flame retardant coated polyester / cotton blended fabric, wherein the drying temperature is 70° C. and the drying time is 4 min.

[0063] (5) The flame-retardant coated polyester / cotton blended fabric prepared in step (43) is then treated four times in sequence through steps (2) to (4).

[0064] The amino group of the amino-terminated branched polyphosphoramide and the hydroxyl group of sodium alginate can be covalently bonded with the active chlorine of cyanuric chloride, and the amino group of the amino-terminated branched polyphosphoramide and the carboxyl group of sodium alginate can be ionically bonded to generate deposition on the surface of polyester / cotton blended fabric.

[0065] According to tests, the polyester / cotton blended fabric prepared by the present invention has a limiting oxygen index of 32.0%, a damaged length of 9.9 cm, and a damaged length of 13.1 cm after 30 washes.

[0066] According to the invention, active chlorine of cyanuric chloride can be covalently bonded with hydroxyl groups on cotton fibers, and then amino groups of amino-terminated branched polyphosphoramide, hydroxyl groups of sodium alginate and active chlorine of cyanuric chloride can be covalently bonded, and amino groups of amino-terminated branched polyphosphoramide and carboxyl groups of sodium alginate can be ionically bonded. On one hand, cyanuric chloride is used as a network crosslinking agent to generate crosslinks between branched chains of amino-terminated branched polyphosphoramide, and sodium alginate and amino-terminated branched polyphosphoramide are ionically bonded, so that amino-terminated branched polyphosphoramide forms a flame-retardant film with high adhesion and poor water solubility on the surface of polyester / cotton blended fabric; on the other hand, covalent crosslinking generated by cyanuric chloride and cotton fibers can further improve the fixation of the flame-retardant film on the fabric surface.

[0067] Example 2

[0068] The present invention provides a method for preparing a durable flame-retardant and antibacterial multifunctional coated polyester fabric, comprising the following steps:

[0069] (1) A dichloromethane solution containing phosphorus oxychloride and a dichloromethane solution containing ethylenediamine are reacted at a certain temperature for a certain time to obtain an amino-terminated branched polyphosphoramide flame retardant. In step (1), the mass ratio of phosphorus oxychloride to dichloromethane is 1:13, the mass ratio of ethylenediamine to dichloromethane is 1:13, and the molar ratio of phosphorus oxychloride to ethylenediamine is 1:2.7.

[0070] Step (1) specifically comprises: under nitrogen protection, slowly adding a dichloromethane solution of phosphorus oxychloride to a trichloromethane solution of ethylenediamine at a rate of 4 ml / min, reacting at 2° C. for 2.7 hours, and then continuing to react at 43° C. for 5.7 hours; the first active chlorine of phosphorus oxychloride has a low reaction temperature, and the remaining active chlorine needs to react at room temperature or a higher temperature; finally, the amino-terminated branched polyphosphoramide is obtained after reduced pressure distillation, ethanol washing, and drying.

[0071] The above reactions were all carried out under nitrogen protection by slowly introducing nitrogen into the reaction vessel. The yield of amino-terminated branched polyphosphoramide was 77% and the weight average molecular weight was 1910.

[0072] (2) Pre-treating a polyester / cotton blended fabric with a cyanuric chloride solution to obtain a pre-treated polyester / cotton blended fabric. In this embodiment, the polyester / cotton blended fabric used is a 50 / 50 polyester / cotton blended fabric. The step (2) specifically includes:

[0073] (21) The pH value of the aqueous solution is adjusted to 9.5 using sodium carbonate, and cyanuric chloride is added to the aqueous solution to obtain a cyanuric chloride solution, wherein the amount of cyanuric chloride used is 24 g / L.

[0074] (22) The polyester / cotton blended fabric was immersed in a cyanuric chloride solution and rolled at room temperature for 10 min. The rolling rate was 93%.

[0075] (23) Drying the impregnated polyester / cotton blended fabric in step (22) to obtain a pretreated polyester / cotton blended fabric, wherein the drying temperature is 65° C. and the drying time is 3.5 min.

[0076] (3) The pretreated polyester / cotton blended fabric is treated with an amino-terminated branched polyphosphoramide flame retardant.

[0077] Step (3) specifically includes:

[0078] (31) The pretreated polyester / cotton blended fabric was immersed in an amino-terminated branched polyphosphoramide flame retardant and rolled at room temperature for 10 minutes, wherein the amount of the amino-terminated branched polyphosphoramide flame retardant was 40 g / L; and the rolling rate was 93%.

[0079] (32) Drying the polyester / cotton blended fabric treated in step (31), wherein the drying temperature is 65° C. and the drying time is 4.5 min.

[0080] (4) The polyester / cotton blended fabric treated in step (3) is treated with a sodium alginate solution to obtain a flame retardant coated polyester / cotton blended fabric. Step (4) specifically comprises:

[0081] (41) Sodium alginate solution is prepared by dissolving sodium alginate in distilled water, wherein the amount of sodium alginate used is 25 g / L.

[0082] (42) The polyester / cotton blended fabric treated in step (3) is immersed in a sodium alginate solution and rolled at room temperature for 10 minutes; the rolling rate is 93%.

[0083] (43) Drying the polyester / cotton blended fabric after the padding in step (42) to obtain a flame retardant coated polyester / cotton blended fabric, wherein the drying temperature is 65° C. and the drying time is 4.5 min.

[0084] (5) The flame-retardant coated polyester / cotton blended fabric prepared in step (43) is then subjected to steps (2) to (4) for three times.

[0085] According to tests, the polyester / cotton blended fabric prepared by the present invention has a limiting oxygen index of 31.2%, a damaged length of 10.6 cm, and a damaged length of 13.6 cm after 30 washes.

[0086] Example 3

[0087] The present invention provides a method for preparing a durable flame-retardant and antibacterial multifunctional coated polyester fabric, comprising the following steps:

[0088] (1) A dichloromethane solution containing phosphorus oxychloride and a dichloromethane solution containing ethylenediamine are reacted at a certain temperature for a certain time to obtain an amino-terminated branched polyphosphoramide flame retardant. In step (1), the mass ratio of phosphorus oxychloride to dichloromethane is 1:10, the mass ratio of ethylenediamine to dichloromethane is 1:10, and the molar ratio of phosphorus oxychloride to ethylenediamine is 1:2.5.

[0089] Step (1) specifically comprises: under nitrogen protection, slowly adding a dichloromethane solution of phosphorus oxychloride to a trichloromethane solution of ethylenediamine at a rate of 3 ml / min, reacting at 0° C. for 3 hours, and then continuing to react at 40° C. for 6 hours; the first active chlorine of phosphorus oxychloride has a low reaction temperature, and the remaining active chlorine needs to react at room temperature or a higher temperature; finally, the amino-terminated branched polyphosphoramide is obtained after reduced pressure distillation, ethanol washing and drying.

[0090] The above reactions were all carried out under nitrogen protection by slowly introducing nitrogen into the reaction vessel. The yield of amino-terminated branched polyphosphoramide was 75% and the weight average molecular weight was 1800.

[0091] (2) Pre-treating a polyester / cotton blended fabric with a cyanuric chloride solution to obtain a pre-treated polyester / cotton blended fabric. In this embodiment, the polyester / cotton blended fabric used is an 80 / 20 polyester / cotton blended fabric. The step (2) specifically includes:

[0092] (21) The pH value of the aqueous solution is adjusted to 9 with sodium carbonate, and cyanuric chloride is added to the aqueous solution to obtain a cyanuric chloride solution, wherein the amount of cyanuric chloride used is 20 g / L.

[0093] (22) The polyester / cotton blended fabric was immersed in a cyanuric chloride solution and rolled at room temperature for 10 min, with a rolling rate of 90%.

[0094] (23) Drying the impregnated polyester / cotton blended fabric in step (22) to obtain a pretreated polyester / cotton blended fabric, wherein the drying temperature is 60° C. and the drying time is 4 min.

[0095] (3) The pretreated polyester / cotton blended fabric is treated with an amino-terminated branched polyphosphoramide flame retardant.

[0096] Step (3) specifically includes:

[0097] (31) The pretreated polyester / cotton blended fabric was immersed in an amino-terminated branched polyphosphoramide flame retardant and rolled at room temperature for 10 minutes, wherein the amount of the amino-terminated branched polyphosphoramide flame retardant was 30 g / L; and the rolling rate was 90%.

[0098] (32) Drying the polyester / cotton blended fabric treated in step (31), wherein the drying temperature is 60° C. and the drying time is 5 min.

[0099] (4) The polyester / cotton blended fabric treated in step (3) is treated with a sodium alginate solution to obtain a flame retardant coated polyester / cotton blended fabric. Step (4) specifically comprises:

[0100] (41) Sodium alginate solution is prepared by dissolving sodium alginate in distilled water, wherein the amount of sodium alginate used is 20 g / L.

[0101] (42) The polyester / cotton blended fabric treated in step (3) is immersed in a sodium alginate solution and rolled at room temperature for 10 minutes; the rolling rate is 90%.

[0102] (43) Drying the polyester / cotton blended fabric after the padding in step (42) to obtain a flame retardant coated polyester / cotton blended fabric, wherein the drying temperature is 60° C. and the drying time is 5 min.

[0103] (5) The flame-retardant coated polyester / cotton blended fabric prepared in step (43) is subjected to steps (2) to (4) twice in sequence.

[0104] According to tests, the polyester / cotton blended fabric prepared by the present invention has a limiting oxygen index of 30.1%, a damaged length of 11.4 cm, and a damaged length of 14.2 cm after 30 washes.

[0105] Example 4

[0106] The present invention provides a method for preparing a durable flame-retardant and antibacterial multifunctional coated polyester fabric, comprising the following steps:

[0107] (1) A dichloromethane solution containing phosphorus oxychloride and a dichloromethane solution containing ethylenediamine are reacted at a certain temperature for a certain time to obtain an amino-terminated branched polyphosphoramide flame retardant. In step (1), the mass ratio of phosphorus oxychloride to dichloromethane is 1:20, the mass ratio of ethylenediamine to dichloromethane is 1:20, and the molar ratio of phosphorus oxychloride to ethylenediamine is 1:3.

[0108] Step (1) specifically comprises: under nitrogen protection, slowly adding a dichloromethane solution of phosphorus oxychloride to a trichloromethane solution of ethylenediamine at a rate of 3 ml / min, reacting at 5° C. for 2 hours, and then continuing to react at 40° C. for 5 hours; the first active chlorine of phosphorus oxychloride has a low reaction temperature, and the remaining active chlorine needs to react at room temperature or a higher temperature; finally, the amino-terminated branched polyphosphoramide is obtained after reduced pressure distillation, ethanol washing and drying.

[0109] The above reactions were all carried out under nitrogen protection by slowly introducing nitrogen into the reaction vessel. The yield of amino-terminated branched polyphosphoramide was 80% and the weight average molecular weight was 2000.

[0110] (2) Pre-treating a polyester / cotton blended fabric with a cyanuric chloride solution to obtain a pre-treated polyester / cotton blended fabric. In this embodiment, the polyester / cotton blended fabric used is a 65 / 35 polyester / cotton blended fabric. This step (2) specifically includes:

[0111] (21) The pH value of the aqueous solution is adjusted to 9 using sodium carbonate, and cyanuric chloride is added to the aqueous solution to obtain a cyanuric chloride solution, wherein the amount of cyanuric chloride used is 30 g / L.

[0112] (22) The polyester / cotton blended fabric was immersed in a cyanuric chloride solution and rolled at room temperature for 10 min, with a rolling rate of 100%.

[0113] (23) Drying the impregnated polyester / cotton blended fabric in step (22) to obtain a pretreated polyester / cotton blended fabric, wherein the drying temperature is 80° C. and the drying time is 2 min.

[0114] (3) The pretreated polyester / cotton blended fabric is treated with an amino-terminated branched polyphosphoramide flame retardant.

[0115] Step (3) specifically includes:

[0116] (31) The pretreated polyester / cotton blended fabric was immersed in an amino-terminated branched polyphosphoramide flame retardant and rolled at room temperature for 10 minutes, wherein the amount of the amino-terminated branched polyphosphoramide flame retardant was 50 g / L and the rolling rate was 100%.

[0117] (32) Drying the polyester / cotton blended fabric treated in step (31), wherein the drying temperature is 80° C. and the drying time is 3 min.

[0118] (4) The polyester / cotton blended fabric treated in step (3) is treated with a sodium alginate solution to obtain a flame retardant coated polyester / cotton blended fabric. Step (4) specifically comprises:

[0119] (41) Sodium alginate solution is prepared by dissolving sodium alginate in distilled water, wherein the amount of sodium alginate used is 30 g / L.

[0120] (42) The polyester / cotton blended fabric treated in step (3) is immersed in a sodium alginate solution and rolled at room temperature for 10 minutes; the rolling rate is 100%.

[0121] (43) Drying the polyester / cotton blended fabric after the padding in step (42) to obtain a flame retardant coated polyester / cotton blended fabric, wherein the drying temperature is 80° C. and the drying time is 3 min.

[0122] (5) The flame-retardant coated polyester / cotton blended fabric prepared in step (43) is then subjected to steps (2) to (4) for four times.

[0123] According to tests, the polyester / cotton blended fabric prepared by the present invention has a limiting oxygen index of 32.5%, a damaged length of 9.3 cm, and a damaged length of 12.7 cm after 30 washes.

[0124] Example 5

[0125] The present invention also provides a polyester / cotton blended fabric, which is prepared by the method in the above embodiments 1-4.

[0126] Comparative Example 1

[0127] The steps are the same as those in Example 1, but step (4) is not performed. Comparative Example 1 does not use sodium alginate to treat the polyester / cotton blended fabric, resulting in poor flame retardancy and poor water washing resistance of the flame retardant polyester / cotton blended fabric. This is because the active groups of the polyester / cotton blended fabric are limited, and the amino-terminated branched polyphosphoramide and sodium alginate coating cannot be firmly bonded to the fabric, resulting in the loss of flame retardancy during washing. According to the test, the polyester / cotton blended fabric prepared in Comparative Example 1 has a limiting oxygen index of 31.5%, a damaged length of 10.3 cm, and a damaged length of 30 cm after 10 washes.

[0128] Comparative Example 2

[0129] The steps are the same as those in Example 1, but step (2) is not performed. Comparative Example 2 does not use cyanuric chloride to treat the polyester / cotton blended fabric, resulting in reduced flame retardancy and poor water washing resistance of the flame retardant polyester / cotton blended fabric, because the amino-terminated branched polyphosphoramide cannot be firmly fixed on the polyester / cotton blended fabric by the cross-linking effect of cyanuric chloride alone, and the amino-terminated branched polyphosphoramide is easily soluble in water, resulting in poor flame retardancy and durability. After testing, the polyester / cotton blended fabric prepared in Comparative Example 2 has a limiting oxygen index of 30.9%, a damaged length of 10.5 cm, and a damaged length of 30 cm after 10 washes.

[0130] It can be seen from this that the limiting oxygen index of the polyester / cotton blended fabric with a durable flame retardant coating of the present invention is not less than 30.1%, the damaged length is not higher than 11.4 cm, and the damaged length after 30 washes is not higher than 14.2 cm, indicating that the polyester / cotton blended fabric with a durable flame retardant coating has excellent flame retardant properties and water washability.

[0131] In summary, (1) in the present invention, the active chlorine of phosphorus oxychloride and the amino group of ethylenediamine can react to form phosphoramide, and the molar ratio between the two is controlled to synthesize amino-terminated branched polyphosphoramide, which is rich in phosphorus and nitrogen elements and has high flame retardant efficiency.

[0132] (2) Although amino-terminated branched polyphosphoramide contains a large number of active amino groups, the active groups on the polyester / cotton blended fabric are limited. It is impossible to firmly fix the amino-terminated branched polyphosphoramide on the polyester / cotton blended fabric by relying solely on the cross-linking effect of cyanuric chloride. In addition, amino-terminated branched polyphosphoramide is easily soluble in water, resulting in poor flame retardancy and durability.

[0133] The present invention deposits amino-terminated branched polyphosphoramide, cyanuric chloride and sodium alginate on a polyester / cotton blended fabric in sequence. Under the action of temperature, the active amino groups of the amino-terminated branched polyphosphoramide, the hydroxyl groups of the sodium alginate and the active chlorine of the cyanuric chloride undergo affinity substitution reactions. On the one hand, cyanuric chloride, as a network crosslinking agent, causes crosslinking between the branches of the amino-terminated branched polyphosphoramide, and the sodium alginate and the amino-terminated branched polyphosphoramide undergo ionic bonding, so that the amino-terminated branched polyphosphoramide forms a flame retardant film with high adhesion and poor water solubility on the surface of the polyester / cotton blended fabric; on the other hand, the covalent crosslinking generated by cyanuric chloride and cotton fibers can further improve the fixation of the flame retardant film on the fabric surface. The amino-terminated branched polyphosphoramide flame retardant, cyanuric chloride and sodium alginate undergo crosslinking on the surface of the polyester / cotton blended fabric and produce a self-deposition coating, thereby giving the coated polyester / cotton blended fabric a durable flame retardant function.

[0134] (3) The amino-terminated branched polyphosphoramide molecules are rich in phosphorus and nitrogen elements, which can form a phosphorus / nitrogen synergistic flame retardant effect. In addition to being a network cross-linking agent, cyanuric chloride can also provide triazine rings and has high carbon-forming properties. Sodium alginate is a good carbon-forming agent. It can construct an intumescent flame retardant system with the amino-terminated branched polyphosphoramide flame retardant and has good expansion and foaming properties during the combustion process. Therefore, the amino-terminated branched polyphosphoramide, cyanuric chloride and sodium alginate self-deposition coating mainly improves the flame retardant properties of polyester / cotton blended fabrics through the expansion flame retardant mechanism, and has high flame retardant efficiency.

[0135] It should be noted that any changes made by those skilled in the art to the specific embodiments of the present invention do not deviate from the scope of the claims of the present invention. Accordingly, the scope of the claims of the present invention is not limited to the above specific embodiments.

Claims

1. A method for preparing a polyester / cotton blended fabric with a polyphosphoramide durable flame retardant coating, characterized in that: It includes the following steps: (1) reacting a dichloromethane solution containing phosphorus oxychloride and a dichloromethane solution containing ethylenediamine at 0-5°C for 2-3 hours, and then continuing to react at 40-50°C for 5-6 hours to obtain an amino-terminated branched polyphosphoramide flame retardant, wherein the mass ratio of phosphorus oxychloride to dichloromethane is 1:10-20, the mass ratio of ethylenediamine to dichloromethane is 1:10-20, and the molar ratio of phosphorus oxychloride to ethylenediamine is 1:2.5-3; (2) Pretreating the polyester / cotton blended fabric with a cyanuric chloride solution to obtain a pretreated polyester / cotton blended fabric; (3) treating the pretreated polyester / cotton blended fabric with an amino-terminated branched polyphosphoramide flame retardant; (4) The polyester / cotton blended fabric treated in step (3) is treated with a sodium alginate solution to obtain a flame retardant coated polyester / cotton blended fabric.

2. The preparation method according to claim 1, characterized in that: Step (1) specifically includes: (11) Under nitrogen protection, slowly add the dichloromethane solution of phosphorus oxychloride to the chloroform solution of ethylenediamine at a rate of 3-5 ml / min; (12) The product of the reaction in step (11) is subjected to reduced pressure distillation, washed with ethanol, and dried to obtain an amino-terminated branched polyphosphoramide flame retardant.

3. The preparation method according to claim 1, characterized in that: Step (2) specifically includes: (21) adjusting the pH value of the aqueous solution to 9-10 with sodium carbonate, adding cyanuric chloride to the aqueous solution to obtain a cyanuric chloride solution, wherein the amount of cyanuric chloride used is 20-30 g / L; (22) Immerse the polyester / cotton blended fabric in a cyanuric chloride solution and perform padding at room temperature for 10 minutes; (23) Drying the impregnated polyester / cotton blended fabric in step (22) to obtain a pretreated polyester / cotton blended fabric, wherein the drying temperature is 60-80° C. and the drying time is 2-4 min.

4. The preparation method according to claim 1, characterized in that: Step (3) specifically includes: (31) Immersing the pretreated polyester / cotton blended fabric in an amino-terminated branched polyphosphoramide flame retardant and padding the fabric within 10 minutes at room temperature, wherein the amount of the amino-terminated branched polyphosphoramide flame retardant is 30-50 g / L; (32) Drying the polyester / cotton blended fabric treated in step (31), wherein the drying temperature is 60-80° C. and the drying time is 3-5 min.

5. The preparation method according to claim 1, characterized in that: Step (4) specifically includes: (41) dissolving sodium alginate in distilled water to prepare a sodium alginate solution, wherein the amount of sodium alginate is 20-30 g / L; (42) immersing the polyester / cotton blended fabric obtained in step (3) in a sodium alginate solution and performing padding at room temperature for 10 minutes; (43) Drying the polyester / cotton blended fabric after the padding in step (42) to obtain a flame retardant coated polyester / cotton blended fabric, wherein the drying temperature is 60-80° C. and the drying time is 3-5 min.

6. The preparation method according to claim 1, characterized in that: Also includes: Repeat steps (2) to (4) 2 to 4 times.

7. The preparation method according to claim 1, characterized in that: The polyester / cotton blended fabric is one or more of 80 / 20 polyester / cotton blended fabric, 65 / 35 polyester / cotton blended fabric and 50 / 50 polyester / cotton blended fabric.

8. A polyester / cotton blended fabric, characterized in that: The polyester / cotton blended fabric is prepared by the method according to any one of claims 1 to 7.

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