CN118600731A - Preparation method of durable flame-retardant and antibacterial multifunctional coated polyester fabric and polyester fabric - Google Patents

Abstract

The present invention provides a method for preparing a durable flame-retardant and antibacterial multifunctional coated polyester fabric and the polyester fabric, the method comprising the following steps: using phosphorus oxychloride and ethylenediamine to react at a certain temperature for a certain time to obtain an amino-terminated branched polyphosphoramide flame retardant; using a 4-phenylbutyraldehyde solution to pretreat the polyester fabric to obtain a pretreated polyester fabric; using an amino-terminated branched polyphosphoramide flame retardant, a mixed solution containing phthalaldehyde and diethyl phosphite to modify the pretreated polyester fabric with a flame-retardant coating. The preparation method of the present invention is simple, and the prepared coated polyester fabric has excellent flame retardant, antibacterial and water-resistant properties.

Description

Preparation method of durable flame-retardant and antibacterial multifunctional coated polyester fabric and polyester fabric

[Technical field]

The invention belongs to the technical field of textile function modification, and relates to a preparation method of a durable flame-retardant and antibacterial multifunctional coated polyester fabric and the polyester fabric.

[Background technology]

With the improvement of living standards and the rapid development of textile technology, people have an increasing demand for multifunctional textiles and higher quality requirements. Multifunctional textiles with flame retardancy, antibacterial and safety protection have received more and more attention. Polyester fabrics have the characteristics of high strength, high modulus and good resilience, and occupy an important position in the modern textile industry. However, polyester fibers are flammable fibers, accompanied by serious molten droplets, and are extremely dangerous to fire. In addition, their antibacterial properties are poor, making it difficult to meet the requirements of safety protection textiles.

With the increasing requirements for ecological and environmental protection, most halogen flame retardants are prohibited from use. Branched phosphoramide flame retardants are a type of dendritic compound with a special structure. They have a large amount of phosphorus and nitrogen content and reactive end groups. They have high flame retardant efficiency and 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 phosphoryl chloride, 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 fabrics.

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.) Using phosphorus oxychloride and diethanolamine as raw materials, polyhydroxy hyperbranched phosphoramide was synthesized, and the flame retardant finishing system of polyhydroxy hyperbranched phosphoramide and 1,2,3,4-butanetetracarboxylic acid crosslinking agent was used to improve 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 serious damage to viscose fabrics. Polyhydroxy hyperbranched phosphoramide is easily soluble in water and gradually dissolves in the washing liquid during the washing process. The water washing resistance of flame retardant viscose fabrics still needs to be further improved. In addition, there are fewer active groups in polyester fabrics, and only hydroxyl and carboxyl groups are contained at the ends of the polyester macromolecular chain, making it difficult to fix polyhydroxy hyperbranched phosphoramide flame retardants on polyester fabrics.

There are great challenges in developing more efficient phosphamide flame retardants and using them for durable flame retardant, antibacterial and multifunctional modification of polyester fabrics.

Therefore, it is necessary to provide a new technical solution.

[Summary of the invention]

In order to solve the above technical problems and overcome the shortcomings in the prior art books, the present invention provides a preparation method of a durable flame retardant and antibacterial multifunctional coated polyester fabric and polyester fabric. The preparation method is simple, and the prepared coated polyester fabric has excellent flame retardant, antibacterial and water resistance.

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

In one aspect, the present invention provides a method for preparing a durable flame retardant and antibacterial multifunctional coated polyester fabric, comprising the following steps:

(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;

(2) pretreating the polyester fabric with a 4-phenylbutyraldehyde solution to obtain a pretreated polyester fabric;

(3) The pretreated polyester fabric is treated with an amino-terminated branched polyphosphoramide flame retardant and a mixed solution containing phthalaldehyde and diethyl phosphite to obtain a multifunctional coated polyester fabric.

Furthermore, in step (1), the mass ratio of phosphorus oxychloride to dichloromethane is 1:10-15, the mass ratio of ethylenediamine to dichloromethane is 1:10-15, and the molar ratio of phosphorus oxychloride to ethylenediamine is 1:2.5-3.

Furthermore, step (1) specifically includes:

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

(12) The product of the reaction in step (11) is subjected to reduced pressure distillation, ethanol washing, and drying to obtain an amino-terminated branched polyphosphoramide flame retardant.

Furthermore, step (2) specifically includes:

(21), immersing the polyester fabric in a 4-phenylbutyraldehyde solution, wherein the solvent in the 4-phenylbutyraldehyde solution is a mixture of water and ethanol, the volume proportion of ethanol is 15-20%, and the amount of 4-phenylbutyraldehyde is 50-70 g/L;

(22) Pre-baking and baking the polyester fabric after impregnation in step (21) in sequence to obtain a pretreated polyester fabric, wherein the pre-baking temperature is 60-80°C, the pre-baking time is 2-4 minutes, the baking temperature is 150-170°C, and the baking time is 3-5 minutes.

Furthermore, in step (3), the phthalaldehyde-containing compound is one or more of terephthalaldehyde, 2,3-dihydroxyterephthalaldehyde, 2,5-dihydroxyterephthalaldehyde, isophthalaldehyde, and 5-hydroxyisophthalaldehyde.

Furthermore, step (3) specifically includes:

(31), dissolving an amino-terminated branched polyphosphoramide flame retardant, phthalaldehyde and diethyl phosphite in a mixed solution of water and ethanol to obtain a finishing solution, wherein the amount of the amino-terminated branched polyphosphoramide flame retardant is 150-250 g/L, the amount of phthalaldehyde is 70-100 g/L, the ethanol accounts for 15-20% of the total volume of the mixed solution, and the molar ratio of diethyl phosphite to phthalaldehyde is 1-1.3:1;

(32), immersing the pretreated polyester fabric into the finishing solution, taking it out and pressing it;

(33) The polyester fabric treated in step (32) is sequentially dried and baked, wherein the drying temperature is 75-85°C and the drying time is 3-5 minutes; the baking temperature is 120-140°C and the time is 3-5 minutes.

Furthermore, the processing times of step (32) is 2 times, and the interval between the 2 times is less than 20 minutes.

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

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

(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.

(2) Although amino-terminated branched polyphosphoramide contains a large number of active amino groups, the number of active groups on polyester fabrics is small, and only hydroxyl and carboxyl active groups are contained at the ends of the polyester macromolecular chains. Therefore, it is impossible to firmly fix amino-terminated branched polyphosphoramide on polyester fabrics by relying on the action of cross-linking agents, and amino-terminated branched polyphosphoramide is easily soluble in water, resulting in poor flame retardancy and durability.

The invention simultaneously adsorbs amino-terminated branched polyphosphoramide, phthalaldehyde and diethyl phosphite on polyester fabric, and under the action of temperature, active amino groups of the amino-terminated branched polyphosphoramide and aldehyde groups of phthalaldehyde undergo Schiff base reaction, and active amino groups of the amino-terminated branched polyphosphoramide, aldehyde groups of phthalaldehyde and P-H bonds of diethyl phosphite undergo Mannich reaction. On the one hand, phthalaldehyde is used as a network cross-linking agent to generate cross-links between the branch chains of the amino-terminated branched polyphosphoramide, so that the amino-terminated branched polyphosphoramide forms a flame-retardant and antibacterial multifunctional film with high adhesion and poor water solubility on the surface of the polyester fabric; on the other hand, the aldehyde groups on the surface of the pretreated polyester fabric can generate Schiff base reaction with the amino groups of the amino-terminated branched polyphosphoramide, so as to further improve the fixation of the flame-retardant and antibacterial multifunctional film on the surface of the fabric. Amino-terminated branched polyphosphoramide flame retardant, containing phthalaldehyde and diethyl phosphite, cross-links on the surface of polyester fabric and produces a self-deposition coating, thereby giving the coated polyester fabric a durable flame retardant function.

(3) The amino-terminated branched polyphosphoramide molecules are rich in phosphorus and nitrogen elements. Diethyl phosphite provides phosphorus, which can form a phosphorus/nitrogen synergistic flame retardant effect. In addition to serving as a network crosslinker, the phthalaldehyde-containing coating can also provide aromatic groups to construct an intumescent flame retardant system with the amino-terminated branched polyphosphoramide flame retardant and diethyl phosphite, which has good expansion and foaming properties during the combustion process. Therefore, the amino-terminated branched polyphosphoramide, phthalaldehyde-containing coating and diethyl phosphite self-deposition coating mainly improves the flame retardant properties of polyester fabrics through the expansion flame retardant mechanism, and has high flame retardant efficiency.

In addition, the amino groups of the amino-terminated branched polyphosphoramide react with the aldehyde groups of the phthalaldehyde-containing compound to form a Schiff base C=N structure, so the coated polyester fabric has excellent antibacterial properties.

【Brief Description of the Drawings】

In order to more clearly illustrate the embodiments of the present invention 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 present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG. 1 is a schematic diagram of the reaction mechanism of the amino-terminated branched polyphosphoramide flame-retardant and antibacterial multifunctional coated polyester fabric of the present invention.

[Specific implementation method]

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.

The invention discloses a method for preparing a durable flame-retardant, antibacterial and multifunctional coated polyester fabric. The method comprises the following steps: firstly, phosphorus oxychloride and ethylenediamine are used to synthesize a polyamino branched polyphosphoramide, then the amino-terminated branched polyphosphoramide, phthalaldehyde and diethyl phosphite are dissolved in a mixed solution of water and ethanol, and then the polyester fabric pretreated with 4-phenylbutyraldehyde is coated by a padding-baking method, so as to prepare the durable flame-retardant, antibacterial and multifunctional polyester fabric.

The following examples describe the preparation method of durable flame retardant and antibacterial multifunctional coated polyester fabric, and perform performance tests on the modified polyester fabric and unmodified polyester fabric prepared in the examples of the present application.

Test standard:

The damage length of modified polyester fabric and unmodified polyester fabric is measured according to GB/T 5455-2014 "Determination of vertical direction damage length, smoldering and afterflaming time of textile combustion performance";

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

The antibacterial rates of modified polyester fabrics and unmodified polyester fabrics were determined according to GB/T 20944.3-2008 “Evaluation of antibacterial properties of textiles Part 3: Oscillation method”.

Example 1

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

(1) A dichloromethane solution containing phosphorus oxychloride and a dichloromethane solution containing ethylenediamine are reacted at a certain temperature for a certain period of time to obtain an amino-terminated branched polyphosphoramide flame retardant. In this step (1), the mass ratio of phosphorus oxychloride to dichloromethane is 1:14, and the mass ratio of ethylenediamine to dichloromethane is 1:14. The molar ratio of phosphorus oxychloride to ethylenediamine is 1:2.8. In theory, phosphorus oxychloride reacts with ethylenediamine to form 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.

Step (1) specifically includes:

First, a dichloromethane solution of phosphorus oxychloride was slowly added dropwise to a trichloromethane solution of ethylenediamine at a rate of 4 ml/min, and the reaction was continued at 4°C for 2.3 hours, and then at 47°C for 5.3 hours. The first active chlorine of phosphorus oxychloride had a low reaction temperature, and the remaining active chlorine needed to react at room temperature or a higher temperature. Finally, the amino-terminated branched polyphosphoramide flame retardant was obtained after reduced pressure distillation, ethanol washing, and drying.

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 2000.

(2) Pre-treating polyester fabric with 4-phenylbutyraldehyde solution to obtain pre-treated polyester fabric. The step (2) specifically comprises: immersing the polyester fabric in the 4-phenylbutyraldehyde solution, wherein the solvent in the 4-phenylbutyraldehyde solution is a mixture of water and ethanol, and the volume of ethanol accounts for 18% of the total volume of the mixture. The amount of 4-phenylbutyraldehyde is 60g/L; the impregnated polyester fabric is pressed, pre-baked and baked in sequence to obtain the pre-treated polyester fabric, wherein the pre-baking temperature is 75°C, the pre-baking time is 3min, the baking temperature is 165°C, the baking time is 4min, and the rolling rate of the polyester fabric is 98%.

(3) The pretreated polyester fabric is treated with an amino-terminated branched polyphosphoramide flame retardant and a mixed solution containing phthalaldehyde and diethyl phosphite to obtain a multifunctional coated polyester fabric.

Step (3) specifically includes:

(31) Dissolve the amino-terminated branched polyphosphoramide flame retardant, 2,5-dihydroxyterephthalaldehyde and diethyl phosphite in a mixed solution of water and ethanol to obtain a finishing solution. The aldehyde group of the terephthalaldehyde-containing group can undergo a Schiff base cross-linking reaction with the amino group of the amino-terminated branched polyphosphoramide to generate a Schiff base C=N structure, so that the amino-terminated branched polyphosphoramide is deposited on the polyester fabric. The high amount of terephthalaldehyde-containing group helps to improve the deposition effect, so the coated polyester fabric has excellent antibacterial properties. Please refer to Figure 1, which is a schematic diagram of the reaction mechanism of the amino-terminated branched polyphosphoramide flame retardant and antibacterial multifunctional coated polyester fabric of the present invention. In this step, the amount of the amino-terminated branched polyphosphoramide flame retardant is 230g/L, the amount of terephthalaldehyde-containing group is 90g/L, ethanol accounts for 18% of the total volume of the mixed solution, and the molar ratio of diethyl phosphite to terephthalaldehyde-containing group is 1.2:1. A high dosage of amino-terminated branched polyphosphoramide can help improve the flame retardant properties of polyester fabrics, but too high a dosage is wasteful.

In addition, Mannich reaction can occur between the amino group of amino-terminated branched polyphosphoramide, the aldehyde group of phthalaldehyde-containing, and the P-H bond of diethyl phosphite, so that diethyl phosphite can be grafted on the polyester fabric through covalent bonds. Theoretically, each mole of phthalaldehyde-containing can react with two moles of diethyl phosphite. The molar ratio of diethyl phosphite to phthalaldehyde-containing is controlled so that one aldehyde group of phthalaldehyde-containing reacts with the amino group of amino-terminated branched polyphosphoramide by Schiff base reaction, and the other aldehyde group reacts with the amino group of amino-terminated branched polyphosphoramide and diethyl phosphite by Mannich reaction. Grafting diethyl phosphite can reduce the amount of amino-terminated branched polyphosphoramide, thereby reducing the influence of flame retardant deposited on the surface of polyester fabric on the fabric feel and mechanical properties. The higher the amount of diethyl phosphite used, the higher the flame retardant efficiency, but too high an amount is wasteful. The amino-terminated branched polyphosphoramide is soluble in water, while phthalaldehyde and diethyl phosphite are easily soluble in ethanol, so a mixed solution of water and ethanol is used.

(32) Immerse the pretreated polyester fabric in the finishing liquid, take it out and press it. Specifically, immerse the pretreated polyester fabric in the finishing liquid, and at room temperature, immerse it twice and press it twice within 20 minutes, and the press rate is 105%. The higher the press rate, the higher the amount of liquid and flame retardant carried by the polyester fabric, and the better the antibacterial and flame retardant effect. However, if it is too high, it will easily lead to unevenness.

(33) The polyester fabric treated in step (32) is dried and baked in sequence, wherein the drying temperature is 82°C and the drying time is 3.5 min; the baking temperature is 135°C and the time is 3.5 min. The amino-terminated branched polyphosphoramide, phthalaldehyde and diethyl phosphite hardly react at room temperature. When the coated polyester fabric is dried and baked, the amino-terminated branched polyphosphoramide, phthalaldehyde and diethyl phosphite undergo Schiff base reaction or Mannich reaction. On the one hand, phthalaldehyde acts as a network crosslinking agent to crosslink the branches of the amino-terminated branched polyphosphoramide, so that the amino-terminated branched polyphosphoramide forms a flame-retardant and antibacterial multifunctional film with high adhesion and poor water solubility on the surface of the polyester fabric; on the other hand, the aldehyde group on the surface of the pretreated polyester fabric can react with the amino group of the amino-terminated branched polyphosphoramide to produce a Schiff base reaction, further improving the fixation of the flame-retardant and antibacterial multifunctional film on the surface of the fabric.

After testing, the limiting oxygen index of the coated polyester fabric prepared in Example 1 of the present invention was 31.4%, the damaged length was 9.8 cm, the antibacterial rates against Escherichia coli and Staphylococcus aureus reached 99.9%, and the damaged length after 30 washes was 12.9 cm.

Example 2

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

(1) reacting a dichloromethane solution containing phosphorus oxychloride and a dichloromethane solution containing ethylenediamine 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 1:12, the mass ratio of ethylenediamine to dichloromethane is 1:12, and the molar ratio of phosphorus oxychloride to ethylenediamine is 1:2.7.

Step (1) specifically includes:

First, a dichloromethane solution of phosphorus oxychloride was slowly added dropwise to a trichloromethane solution of ethylenediamine at a rate of 4 ml/min, and the reaction was continued at 2°C for 2.7 hours, and then at 43°C for 5.7 hours. The first active chlorine of phosphorus oxychloride had a low reaction temperature, and the remaining active chlorine needed to react at room temperature or a higher temperature. Finally, the amino-terminated branched polyphosphoramide flame retardant was obtained after reduced pressure distillation, ethanol washing, and drying.

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 76% and the weight average molecular weight was 1850.

(2) Pre-treating the polyester fabric with a 4-phenylbutyraldehyde solution to obtain a pre-treated polyester fabric. The step (2) specifically comprises: immersing the polyester fabric in a 4-phenylbutyraldehyde solution, wherein the solvent in the 4-phenylbutyraldehyde solution is a mixture of water and ethanol, the volume proportion of ethanol is 17%, and the amount of 4-phenylbutyraldehyde is 55 g/L; the impregnated polyester fabric is sequentially pressed, pre-baked and baked to obtain a pre-treated polyester fabric, wherein the pre-baking temperature is 75° C., the pre-baking time is 3 min, the baking temperature is 160° C., the baking time is 4 min, and the rolling rate of the polyester fabric is 95%.

(3) The pretreated polyester fabric was treated with an amino-terminated branched polyphosphoramide flame retardant, a mixed solution containing phthalaldehyde and diethyl phosphite to obtain a multifunctional coated polyester fabric.

Step (3) specifically includes:

(31) dissolving an amino-terminated branched polyphosphoramide flame retardant, 2,3-dihydroxyterephthalaldehyde and diethyl phosphite in a mixed solution of water and ethanol to obtain a finishing solution. In this step, the amount of the amino-terminated branched polyphosphoramide flame retardant is 190 g/L, the amount of terephthalaldehyde is 80 g/L, the ethanol accounts for 17% of the total volume of the mixed solution, and the molar ratio of diethyl phosphite to terephthalaldehyde is 1.1:1.

(32) The pretreated polyester fabric is immersed in the finishing liquid, and then taken out and pressed. Specifically, the pretreated polyester fabric is immersed in the finishing liquid, and at room temperature, it is immersed twice and pressed twice within 20 minutes, and the pressing rate is 100%. The higher the pressing rate, the higher the amount of liquid and flame retardant carried by the polyester fabric, and the better the antibacterial and flame retardant effect. However, if the pressing rate is too high, it will easily lead to unevenness.

(33) The polyester fabric treated in step (32) is sequentially dried and baked, wherein the drying temperature is 80° C. and the drying time is 4 min; and the baking temperature is 125° C. and the time is 4 min.

After testing, the limiting oxygen index of the coated polyester fabric prepared in Example 2 of the present invention is 30.5%, the damaged length is 10.5 cm, the antibacterial rates against Escherichia coli and Staphylococcus aureus are 99.9% and 99.1% respectively, and the damaged length after 30 washes is 13.5 cm.

Example 3

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

(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, and the mass ratio of ethylenediamine to dichloromethane is 1:10. The molar ratio of phosphorus oxychloride to ethylenediamine is 1:2.5.

Step (1) specifically includes:

First, a dichloromethane solution of phosphorus oxychloride is slowly added dropwise to a trichloromethane solution of ethylenediamine at a rate of 3 ml/min, and the reaction is continued at 0°C for 3 hours, and then at 40°C for 5.3 hours. The reaction temperature of the first active chlorine of phosphorus oxychloride is low, and the remaining active chlorine needs to react at room temperature or higher temperature. Finally, the amino-terminated branched polyphosphoramide flame retardant is obtained after reduced pressure distillation, ethanol washing and drying.

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.

(2) Pre-treating the polyester fabric with a 4-phenylbutyraldehyde solution to obtain a pre-treated polyester fabric. The step (2) specifically comprises: immersing the polyester fabric in a 4-phenylbutyraldehyde solution, wherein the solvent in the 4-phenylbutyraldehyde solution is a mixture of water and ethanol, the volume proportion of ethanol is 15%, and the amount of 4-phenylbutyraldehyde is 50 g/L; the impregnated polyester fabric is sequentially pressed, pre-baked and baked to obtain a pre-treated polyester fabric, wherein the pre-baking temperature is 70° C., the pre-baking time is 4 min, the baking temperature is 150° C., the baking time is 5 min, and the rolling rate of the polyester fabric is 90%.

(3) The pretreated polyester fabric was treated with an amino-terminated branched polyphosphoramide flame retardant, a mixed solution containing phthalaldehyde and diethyl phosphite to obtain a multifunctional coated polyester fabric.

Step (3) specifically includes:

(31) dissolving an amino-terminated branched polyphosphoramide flame retardant, terephthalaldehyde and diethyl phosphite in a mixed solution of water and ethanol to obtain a finishing solution. In this step, the amount of the amino-terminated branched polyphosphoramide flame retardant is 150 g/L, the amount of terephthalaldehyde is 70 g/L, the ethanol accounts for 15% of the total volume of the mixed solution, and the molar ratio of diethyl phosphite to terephthalaldehyde is 1:1.

(32) The pretreated polyester fabric is immersed in the finishing liquid, and then taken out and pressed. Specifically, the pretreated polyester fabric is immersed in the finishing liquid, and at room temperature, the pretreated polyester fabric is immersed twice and pressed twice within 20 minutes, and the pressing rate is 90%. The higher the pressing rate, the higher the amount of liquid and flame retardant carried by the polyester fabric, and the better the antibacterial and flame retardant effect. However, if the pressing rate is too high, it will easily lead to unevenness.

(33) The polyester fabric treated in step (32) is sequentially dried and baked, wherein the drying temperature is 75° C. and the drying time is 5 min; and the baking temperature is 120° C. and the time is 5 min.

After testing, the limiting oxygen index of the coated polyester fabric prepared in Example 3 of the present invention is 29.3%, the damaged length is 11.5 cm, the antibacterial rates against Escherichia coli and Staphylococcus aureus are 90.1% and 87.8% respectively, and the damaged length after 30 washes is 14.2 cm.

Example 4

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

(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, and the mass ratio of ethylenediamine to dichloromethane is 1:15. The molar ratio of phosphorus oxychloride to ethylenediamine is 1:3.

Step (1) specifically includes:

First, a dichloromethane solution of phosphorus oxychloride is slowly added dropwise to a trichloromethane solution of ethylenediamine at a rate of 5 ml/min, and the reaction is continued at 5°C for 2 hours, and then at 50°C for 5 hours. The reaction temperature of the first active chlorine of phosphorus oxychloride is low, and the remaining active chlorine needs to react at room temperature or a higher temperature. Finally, the amino-terminated branched polyphosphoramide flame retardant is obtained after reduced pressure distillation, ethanol washing, and drying.

The above reactions were all carried out under nitrogen protection by slowly introducing nitrogen into the reaction container. The yield of amino-terminated branched polyphosphoramide was 80% and the weight average molecular weight was 1900.

(2) Pre-treating the polyester fabric with a 4-phenylbutyraldehyde solution to obtain a pre-treated polyester fabric. The step (2) specifically comprises: immersing the polyester fabric in a 4-phenylbutyraldehyde solution, wherein the solvent in the 4-phenylbutyraldehyde solution is a mixture of water and ethanol, the volume proportion of ethanol is 20%, and the amount of 4-phenylbutyraldehyde is 70 g/L; the impregnated polyester fabric is sequentially pressed, pre-baked and baked to obtain a pre-treated polyester fabric, wherein the pre-baking temperature is 60° C., the pre-baking time is 2 min, the baking temperature is 170° C., the baking time is 3 min, and the rolling rate of the polyester fabric is 100%.

(3) treating the pretreated polyester fabric with an amino-terminated branched polyphosphoramide flame retardant, a mixed solution containing phthalaldehyde and diethyl phosphite to obtain a multifunctional coated polyester fabric. Step (3) specifically comprises:

(31) dissolving an amino-terminated branched polyphosphoramide flame retardant, 5-hydroxyisophthalaldehyde and diethyl phosphite in a mixed solution of water and ethanol to obtain a finishing solution. In this step, the amount of the amino-terminated branched polyphosphoramide flame retardant is 250 g/L, the amount of isophthalaldehyde is 100 g/L, the ethanol accounts for 20% of the total volume of the mixed solution, and the molar ratio of diethyl phosphite to isophthalaldehyde is 1.3:1.

(32) The pretreated polyester fabric is immersed in the finishing liquid, taken out and pressed. Specifically, the pretreated polyester fabric is immersed in the finishing liquid, and at room temperature, it is immersed twice and pressed twice within 20 minutes, and the pressing rate is 110%. The higher the pressing rate, the higher the amount of liquid and flame retardant carried by the polyester fabric, and the better the antibacterial and flame retardant effect. However, if it is too high, it will easily lead to unevenness.

(33) The polyester fabric treated in step (32) is sequentially dried and baked, wherein the drying temperature is 85° C. and the drying time is 3 min; and the baking temperature is 140° C. and the time is 3 min.

After testing, the limiting oxygen index of the coated polyester fabric prepared in Example 4 of the present invention was 32.0%, the damaged length was 9.4 cm, the antibacterial rates against Escherichia coli and Staphylococcus aureus reached 99.9%, and the damaged length after 30 washes was 12.6 cm.

Example 5

The present invention also provides a multifunctional coated polyester fabric, which is prepared by the method in the above embodiments 1-4.

Comparative Example 1

The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, aliphatic aldehydes such as glutaraldehyde are used instead of phthalaldehyde in the present invention as a crosslinking agent, and the rest is the same as Example 1.

In Comparative Example 1, aliphatic aldehydes such as glutaraldehyde are used as cross-linking agents, and the prepared polyester fabric has poor flame retardant efficiency and poor durability. Therefore, the coating cross-linked with glutaraldehyde will still retain a certain water solubility and cannot form a self-deposition coating; after testing, the flame retardant and antibacterial multifunctional coated polyester fabric prepared in Comparative Example 1 has a limiting oxygen index of 28.1%, a damaged length of 12.7 cm, and loses the flame retardant effect after 10 washes, with a damaged length of 30 cm.

Comparative Example 2

The difference between Comparative Example 2 and Example 1 is that diethyl phosphite is not added in Comparative Example 2, and the rest is the same as Example 1.

In Comparative Example 2, diethyl phosphite was not added, and the flame retardant efficiency and water washing resistance of the flame retardant polyester fabric prepared therefrom were poor. Because the dosage of the amino-terminated branched polyphosphoramide flame retardant was low and the amount of the flame retardant grafted on the polyester fabric was limited, it was easy to lose its flame retardant properties after washing; after testing, the limiting oxygen index of the flame retardant and antibacterial multifunctional coated polyester fabric in Comparative Example 2 was 27.2%, and the damaged length was 13.1 cm. After 10 washes, the flame retardant effect was lost, and the damaged length was 30 cm.

It can be seen from this that the limiting oxygen index of the durable flame retardant and antibacterial multifunctional coated polyester fabric of the present invention is not less than 29.3%, the damaged length (charcoal length) is not higher than 11.5 cm, the damaged length after 30 water washings is not higher than 14.2 cm, and the antibacterial rates against Escherichia coli and Staphylococcus aureus are higher than 90.1% and 87.8%, respectively, indicating that the durable flame retardant and antibacterial multifunctional coated polyester fabric has excellent antibacterial properties, flame retardant properties and water washability.

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.

(2) Although amino-terminated branched polyphosphoramide contains a large number of active amino groups, the number of active groups on polyester fabrics is small, and only hydroxyl and carboxyl active groups are contained at the ends of the polyester macromolecular chains. Therefore, it is impossible to firmly fix amino-terminated branched polyphosphoramide on polyester fabrics by relying on the action of cross-linking agents, and amino-terminated branched polyphosphoramide is easily soluble in water, resulting in poor flame retardancy and durability.

The invention simultaneously adsorbs amino-terminated branched polyphosphoramide, phthalaldehyde and diethyl phosphite on polyester fabric, and under the action of temperature, active amino groups of the amino-terminated branched polyphosphoramide and aldehyde groups of phthalaldehyde undergo Schiff base reaction, and active amino groups of the amino-terminated branched polyphosphoramide, aldehyde groups of phthalaldehyde and P-H bonds of diethyl phosphite undergo Mannich reaction. On the one hand, phthalaldehyde is used as a network cross-linking agent to generate cross-links between the branch chains of the amino-terminated branched polyphosphoramide, so that the amino-terminated branched polyphosphoramide forms a flame-retardant and antibacterial multifunctional film with high adhesion and poor water solubility on the surface of the polyester fabric; on the other hand, the aldehyde groups on the surface of the pretreated polyester fabric can generate Schiff base reaction with the amino groups of the amino-terminated branched polyphosphoramide, so as to further improve the fixation of the flame-retardant and antibacterial multifunctional film on the surface of the fabric. Amino-terminated branched polyphosphoramide flame retardant, containing phthalaldehyde and diethyl phosphite, cross-links on the surface of polyester fabric and produces a self-deposition coating, thereby giving the coated polyester fabric a durable flame retardant function.

(3) In the present invention, the amino-terminated branched polyphosphoramide molecules are rich in phosphorus and nitrogen elements, and diethyl phosphite provides phosphorus to form a phosphorus/nitrogen synergistic flame retardant effect. In addition to serving as a network crosslinking agent, the phthalaldehyde-containing compound can also provide aromatic groups to construct an intumescent flame retardant system with the amino-terminated branched polyphosphoramide flame retardant and diethyl phosphite, which has good expansion and foaming properties during the combustion process; therefore, the amino-terminated branched polyphosphoramide, phthalaldehyde-containing compound and diethyl phosphite self-deposition coating mainly improves the flame retardant properties of polyester fabrics through an expansion flame retardant mechanism, and has a high flame retardant efficiency.

In addition, the amino groups of the amino-terminated branched polyphosphoramide react with the aldehyde groups of the phthalaldehyde-containing compound to form a Schiff base C=N structure, so the coated polyester fabric has excellent antibacterial properties.

It should be noted that any changes made by those skilled in the art to the specific implementation 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 implementation.

Claims (8)

1. The preparation method of the durable flame-retardant antibacterial multifunctional coating polyester fabric is characterized by comprising the following steps of:

(1) Reacting a methylene dichloride solution containing phosphorus oxychloride with a methylene dichloride solution containing ethylenediamine at a certain temperature for a certain time to prepare the amino-terminated branched polyphosphazene flame retardant;

(2) Pretreating the polyester fabric by adopting a 4-phenylbutyraldehyde solution to obtain a pretreated polyester fabric;

(3) And treating the pretreated polyester fabric by adopting an amino-terminated branched polyphosphazene flame retardant and a mixed solution containing phthalaldehyde and diethyl phosphite to obtain the multifunctional coating polyester fabric.

2. The method according to claim 1, wherein in the step (1), the mass ratio of phosphorus oxychloride to methylene dichloride is 1:10-15, the mass ratio of ethylenediamine to methylene dichloride is 1:10-15, and the molar ratio of phosphorus oxychloride to ethylenediamine is 1:2.5 to 3.

3. The method according to claim 1, wherein step (1) specifically comprises:

(11) Under the protection of nitrogen, slowly dripping a dichloromethane solution of phosphorus oxychloride into a trichloromethane solution of ethylenediamine at a rate of 3-5 ml/min, reacting for 2-3 h at 0-5 ℃, and then continuously reacting for 5-6 h at 40-50 ℃;

(12) And (3) carrying out reduced pressure distillation, ethanol washing and drying on the product of the reaction in the step (11) to obtain the amino-terminated branched polyphosphazene flame retardant.

4. The method according to claim 1, wherein step (2) specifically comprises:

(21) Immersing the polyester fabric into a 4-phenyl butyraldehyde solution, wherein the solvent in the 4-phenyl butyraldehyde solution is a mixed solution of water and ethanol, the volume ratio of the ethanol is 15-20%, and the dosage of the 4-phenyl butyraldehyde is 50-70 g/L;

(22) And (3) sequentially carrying out pre-drying and baking on the polyester fabric impregnated in the step (21) to obtain the pre-treated polyester fabric, wherein the pre-drying temperature is 60-80 ℃, the pre-drying time is 2-4 min, the baking temperature is 150-170 ℃, and the baking time is 3-5 min.

5. The method according to claim 1, wherein in the step (3), the terephthalaldehyde is one or more of terephthalaldehyde, 2, 3-dihydroxyterephthalaldehyde, 2, 5-dihydroxyterephthalaldehyde, isophthalaldehyde, and 5-hydroxyisophthalaldehyde.

6. The method according to claim 1, wherein step (3) specifically comprises:

(31) Dissolving an amino-terminated branched polyphosphazene flame retardant, a benzene-containing dicarboxaldehyde and diethyl phosphite in a mixed solution of water and ethanol to obtain a finishing liquid, wherein the dosage of the amino-terminated branched polyphosphazene flame retardant is 150-250 g/L, the dosage of the benzene-containing dicarboxaldehyde is 70-100 g/L, the ethanol accounts for 15-20% of the total volume of the mixed solution, and the molar ratio of the diethyl phosphite to the benzene-containing dicarboxaldehyde is 1-1.3:1;

(32) Immersing the pretreated polyester fabric into the finishing liquid, and taking out and rolling;

(33) Sequentially carrying out drying and baking treatment on the polyester fabric treated in the step (32), wherein the drying temperature is 75-85 ℃ and the drying time is 3-5 min; the baking temperature is 120-140 ℃ and the baking time is 3-5 min.

7. The method of claim 1, wherein the number of treatments of step (32) is 2, the 2 intervals being less than 20 minutes.

8. A polyester fabric, characterized in that it is produced by the method according to any one of claims 1 to 7.