An active phosphate flame retardant and its preparation method and application

Abstract

The present invention belongs to the technical field of flame retardant finishing of textiles, and relates to an active phosphate flame retardant, a preparation method and application thereof. The preparation method of the active phosphate flame retardant comprises the following steps: (1) reacting phosphorus oxychloride with pentaerythritol to generate pentaerythritol phosphoryl chloride; (2) reacting ethanolamine and phenylethanol with pentaerythritol phosphoryl chloride to generate an intermediate product capped with ethanolamine at one end and phenylethanol at the other end; (3) reacting the intermediate product with cyanuric chloride to generate an active phosphate flame retardant. The application of the active phosphate flame retardant is to flame retardant finish of polyester / cotton blended fabrics. The obtained durable flame retardant polyester / cotton blended fabric has a limiting oxygen index higher than 30.2%, a damaged length lower than 9.2 cm, and a damaged length still lower than 14.7 cm after 40 times of washing, meeting the B1 standard, and having excellent flame retardant properties and water washability.

Description

Technical Field

[0001] The invention belongs to the technical field of flame retardant finishing of textiles, and specifically relates to an active phosphate flame retardant and a preparation method and application thereof. Background Art

[0002] Polyester / cotton blended fabrics have the advantages of crisp appearance, easy washing and quick drying, breathable and comfortable, and high strength. They are widely used in labor protection clothing, fire protection clothing, military combat uniforms, bedding, and interior decoration fabrics. However, polyester / cotton fabrics are easy to burn, and they affect each other during the combustion process. This is because the combustion of thermoplastic and non-thermoplastic blended fibers is no longer the superposition or average of the combustion effects of single components, but a certain degree of intensified combustion occurs, which is called the "wick effect". Therefore, flame retardant finishing of polyester / cotton blended fabrics is of great significance.

[0003] At present, there are still great challenges in the durable flame retardant finishing of polyester-cotton blended fabrics. It is difficult to achieve a durable flame retardant effect on polyester / cotton blended fabrics by using a single durable flame retardant for cotton, and it is difficult to achieve a durable flame retardant effect on polyester / cotton blended fabrics by combining conventional cotton flame retardants with polyester flame retardants.

[0004] For example, document 1 (Miao Yuzhen. Durable flame retardant finishing process for polyester-cotton fabrics [J], Printing and Dyeing, 2003, 29(2):18-19.) uses a mixture of pure cotton durable flame retardant finishing agent FK-103 and polyester durable flame retardant finishing agent FK-106, and then achieves a flame retardant effect through resin finishing; however, this flame retardant polyester-cotton fabric loses its flame retardant effect after two washes, the damaged length exceeds 15 cm, and there is potential formaldehyde release during use.

[0005] For example, in reference 2 (Chen Wei, Guan Jinping, Kuang Xiaohui, et al. Electrostatic layer-by-layer self-assembly flame retardant finishing of dopamine-modified polyester-cotton [J]. Printing and Dyeing, 2017, 43(2):11-15.), chitosan and sodium phytate were used as assembly liquids to perform flame retardant finishing on dopamine-modified polyester-cotton blended fabrics by electrostatic layer-by-layer self-assembly. After assembling 15 positive and negative ions alternately deposited (i.e., 15 layers), the limiting oxygen index of the polyester-cotton fabric increased to 28.7%. However, since the flame retardant coating cannot form a covalent bond with the polyester-cotton fabric, the washability of the flame retardant fabric is poor, and the hand feel of the flame retardant fabric is also poor.

[0006] For example, reference 3 (Zhang Guangxian, Huang Tiandong. New durable ammonium phosphonate flame retardant for cotton [J]. Printing and Dyeing Auxiliary Agents, 2023, 40(11):10-16.) synthesized a new type of aminotrimethyl diphosphonic acid ammonium phosphonate flame retardant. The flame retardant can form covalent bonds with the hydroxyl groups of cotton fibers when baked at 175°C. The finished cotton fabric can withstand 50 washes. However, high-temperature baking causes significant damage to the strength of the cotton fabric. However, when the aminotrimethyl diphosphonic acid ammonium phosphonate flame retardant is used to finish polyester-cotton blended fabrics, the amount of the flame retardant grafted to the cotton fibers is limited, and a durable flame retardant effect cannot be obtained.

[0007] Therefore, it is necessary to study a new type of flame retardant for durable flame retardant finishing of polyester-cotton blended fabrics. Summary of the invention

[0008] The purpose of the present invention is to solve the problems existing in the prior art and to provide an active phosphate flame retardant and a preparation method and application thereof.

[0009] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] An active phosphate flame retardant, the structural formula is as follows:

[0011] .

[0012] The present invention also provides a method for preparing the above-mentioned active phosphate flame retardant, comprising the following steps:

[0013] (1) reacting phosphorus oxychloride with pentaerythritol to generate pentaerythritol phosphoryl chloride;

[0014] (2) reacting ethanolamine and phenylethanol with pentaerythritol phosphoryl chloride to generate an intermediate product capped with ethanolamine at one end and phenylethanol at the other end;

[0015] (3) The intermediate product is reacted with cyanuric chloride to generate an active phosphate flame retardant.

[0016] As the preferred technical solution:

[0017] In the method described above, in steps (1) to (3), the molar ratio of pentaerythritol, phosphorus oxychloride, ethanolamine and phenylethanol is 1:2 to 2.2:1:1 to 1.2, and the molar ratio of cyanuric chloride to the intermediate product is 1 to 1.1:1.

[0018] In the method as described above, in step (1), the reaction temperature is 25-30°C and the reaction time is 3-4h; in step (2), the reaction temperature is 35-40°C and the reaction time is 1.5-2.5h; in step (3), the reaction temperature is 0-5°C and the reaction time is 3-4h.

[0019] The method described above, the specific process is as follows:

[0020] (a) dissolving phosphorus oxychloride and pentaerythritol in a solvent (dimethyl sulfoxide) and reacting to generate pentaerythritol phosphoryl chloride;

[0021] (b) adding ethanolamine and phenylethanol to the reaction system of step (a), reacting to generate an intermediate product having one end capped with ethanolamine and the other end capped with phenylethanol;

[0022] (c) adding the intermediate product obtained in step (b) into water to obtain an intermediate product aqueous solution, adjusting the pH value of the intermediate product aqueous solution to 6.5-7.5 with sodium carbonate, adding the intermediate product aqueous solution into a cyanuric chloride aqueous dispersion to obtain a mixture, stirring to react, and generating an active phosphate flame retardant. After the reaction is completed, purifying by reduced pressure distillation.

[0023] In the method as described above, in step (a), the mass ratio of the solvent to phosphorus oxychloride is 30-40:1; in step (c), the mass ratio of water to cyanuric chloride in the mixture is 30-40:1.

[0024] The present invention also provides the use of the above-mentioned active phosphate flame retardant for flame retardant finishing of polyester / cotton blended fabrics.

[0025] As the preferred technical solution:

[0026] The specific process of the application as described above is as follows: the active phosphate flame retardant is dissolved in water to obtain a flame retardant finishing liquid, the polyester / cotton blended fabric is added to the flame retardant finishing liquid, and the reaction is carried out at 85-99°C for 30 minutes. During this process, the dichloro-s-triazine active group of the active phosphate flame retardant reacts with the hydroxyl group of the cotton fiber by a nucleophilic substitution reaction, and then an alkali agent (sodium carbonate or sodium bicarbonate) is added to adjust the pH value of the system to 7.5-8.5 and then react for 40-60 minutes, which can further promote the nucleophilic substitution reaction between the dichloro-s-triazine active group of the active phosphate flame retardant and the hydroxyl group of the cotton fiber. The polyester / cotton blended fabric is taken out, and rolling, pre-baking, and baking are carried out in sequence (during this process, the molecular chain movement of polyester (i.e., the material of polyester fiber) is accelerated, which promotes the active phosphate flame retardant to enter the interior of the polyester fiber, and the active phosphate flame retardant is rich in cyclic phosphate ester structure and benzene ring structure, and is combined with the polyester fiber through the principle of similar dissolution), to obtain a durable flame retardant polyester / cotton blended fabric.

[0027] In the above application, the concentration of active phosphate flame retardant in the flame retardant finishing liquid is 175~250g / L. The higher the concentration of active phosphate flame retardant, the more helpful it is to improve the flame retardant properties of polyester / cotton blended fabrics, but too high a concentration is wasteful.

[0028] In polyester / cotton blended fabrics, the content of polyester is 20~80wt%;

[0029] The bath ratio of polyester / cotton blended fabric to flame retardant finishing liquid is 1:30~40;

[0030] The rolling margin of rolling is 90~100%;

[0031] The pre-baking temperature is 65~75℃, and the pre-baking time is 2~3min;

[0032] The baking temperature is 140~150℃ and the baking time is 3~4min.

[0033] For the above application, the limiting oxygen index of the durable flame retardant polyester / cotton blended fabric is higher than 30.2%, the damaged length is lower than 9.2 cm, and the damaged length is still lower than 14.7 cm after 40 washes, meeting the B1 standard and having excellent flame retardant and washable properties;

[0034] The active phosphate flame retardant of the invention contains dichloro-s-triazine active groups, cyclic phosphate structures and benzene ring structures at the same time. The dichloro-s-triazine active groups can undergo nucleophilic substitution reaction with the hydroxyl groups of cotton fibers to generate strong covalent bond bonding, with high reaction efficiency and mild reaction conditions. The cyclic phosphate structures and the benzene ring structures have good affinity with polyester fibers and are bonded by the principle of like dissolves like. Moreover, there is a certain distance between the dichloro-s-triazine active groups and the benzene ring structures and the cyclic phosphate structures, and there is also a certain distance between the polyester component and the cotton component in the polyester / cotton blended fabric. The two distances match each other. When the active phosphate flame retardant at one end is After the active group of dichloro-s-triazine forms a covalent bond with the cotton fiber, the cyclic phosphate structure and the benzene ring structure at the other end can find a suitable distance to combine with the polyester fiber during the thermal movement process; therefore, the active phosphate flame retardant has a strong binding force with the polyester / cotton blended fabric, and the obtained modified polyester / cotton blended fabric has excellent water washing resistance; the cyclic phosphate structure acts as an acid source, the active group of dichloro-s-triazine and the amino structure of ethanolamine act as a gas source, and the aromatic structure of the active group of dichloro-s-triazine acts as a carbonizing agent, organically constructing an expansion flame retardant system with high flame retardant efficiency, and the obtained modified polyester / cotton blended fabric has excellent flame retardant properties;

[0035] The active phosphate flame retardant molecular chain of the present invention contains one benzene ring structure and one cyclic phosphate structure. The binding force between the benzene ring structure and the polyester fiber is greater than that between the cyclic phosphate structure and the polyester fiber. Generally speaking, when the flame retardant molecular chain contains two structures that can bind to the polyester fiber, in order to improve the binding force between the flame retardant and the polyester fiber, those skilled in the art will design the two structures that bind to the polyester fiber as benzene ring structures. However, the present invention unexpectedly finds that the binding strength between the flame retardant containing one benzene ring structure and one cyclic phosphate structure and the polyester fiber is higher than that between the flame retardant containing two benzene ring structures and the polyester fiber. It is speculated that the possible reason is that during the high-temperature baking process, the flame retardant molecular chain and the polyester molecular chain of the polyester fiber are both in a thermal motion state, and the two molecular chains are both looking for suitable binding sites to form a flame retardant having a benzene ring structure and a cyclic phosphate structure. Combined with another molecular chain, the number of binding sites with benzene ring structure in polyester molecular chain is limited, and there is mutual competition when the flame retardant molecular chain containing two benzene ring structures combines with these binding sites, which ultimately leads to most flame retardant molecular chains having only one benzene ring structure combined with polyester molecular chain, and the number of connection points between flame retardant molecular chain and polyester molecular chain is 1. The flame retardant molecular chain is suspended on the polyester molecular chain, and the two cannot form a chimeric structure. When the flame retardant molecular chain contains 1 benzene ring structure and 1 cyclic phosphate structure, when the benzene ring structure looks for a suitable binding site to combine with the polyester molecular chain, the cyclic phosphate structure is also looking for a suitable binding site to combine with the polyester molecular chain. The number of connection points between the flame retardant molecular chain and the polyester molecular chain is 2, and the two can form a chimeric structure, thereby improving the binding force between the flame retardant molecular chain and polyester fiber.

[0036] Beneficial effects:

[0037] (1) The active phosphate flame retardant of the present invention contains dichlorotriazine active groups, cyclic phosphate structures, and benzene ring structures. The dichlorotriazine active groups can form a strong covalent bond with the hydroxyl groups of cotton fibers. The cyclic phosphate structures and benzene ring structures have good binding force with polyester fibers through the principle of like dissolves like, thereby achieving a strong bond between the active phosphate flame retardant and the cotton fibers and polyester fibers.

[0038] (2) There is a certain distance between the dichlorotriazine active group of the active phosphate ester flame retardant of the present invention and the benzene ring structure and the cyclic phosphate ester structure. There is also a certain distance between the polyester component and the cotton component in the polyester / cotton blended fabric. These two distances match each other. When the dichlorotriazine active group at one end of the active phosphate ester flame retardant forms a covalent bond with the cotton fiber, the cyclic phosphate ester structure and the benzene ring structure at the other end can find a suitable distance to combine with the polyester fiber during thermal movement, which is beneficial to improving the binding force between the active phosphate ester flame retardant and the cotton fiber and polyester fiber.

[0039] (3) The molecular chain of the active phosphate flame retardant of the present invention forms a chimeric structure with the polyester molecular chain of the polyester fiber, which is beneficial to improving the bonding force between the active phosphate flame retardant and the polyester fiber.

[0040] (4) The active phosphate flame retardant of the present invention has a strong bonding force with cotton fiber and polyester fiber, and the finally obtained durable flame retardant polyester / cotton blended fabric has excellent water wash resistance; the cyclic phosphate structure of the active phosphate flame retardant of the present invention acts as an acid source, the amino structure of the active group of dichlorotriazine and the amino structure of ethanolamine act as a gas source, and the aromatic structure of the active group of dichlorotriazine acts as a carbonizing agent, thereby constructing an expansion flame retardant system with high flame retardant efficiency, and the finally obtained durable flame retardant polyester / cotton blended fabric has excellent flame retardant properties.

[0041] (5) The durable flame-retardant polyester / cotton blended fabric of the present invention has no potential formaldehyde release during use, is environmentally friendly and non-toxic, and has wide application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the synthesis route of the active phosphate flame retardant of the present invention;

[0043] Figure 2 is a hydrogen nuclear magnetic resonance spectrum of the active phosphate flame retardant of the present invention;

[0044] Figure 3 It is a vertical burning test diagram of the flame retardant polyester / cotton blended fabric of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0046] The testing methods of the relevant performance indicators in the following embodiments and comparative examples are as follows:

[0047] Limiting oxygen index: Tested in accordance with GB / T 5454-1997 "Oxygen Index Method for Textile Combustion Performance Test".

[0048] Damage length: measured in accordance with GB / T 5455-2014 "Determination of smoldering and afterflaming time of damage length in vertical direction of burning performance of textiles".

[0049] Damaged length after 40 washes: First wash the fabric 40 times with water according to AATCC 61-2013 "Accelerated test for color fastness to household and commercial washing" standard, and then test the damaged length of the fabric with reference to GB / T 5455-2014 "Determination of damage length in vertical direction, smoldering and afterflaming time of textile combustion performance" standard.

[0050] Example 1

[0051] A method for preparing an active phosphate flame retardant, such as Figure 1 As shown, the steps are as follows:

[0052] (1) Preparation of raw materials;

[0053] Phosphorus oxychloride;

[0054] Pentaerythritol;

[0055] Ethanolamine;

[0056] Phenylethyl alcohol;

[0057] Solvent: dimethyl sulfoxide;

[0058] Sodium carbonate;

[0059] Water: deionized water;

[0060] Cyanuric chloride;

[0061] (2) dissolving phosphorus oxychloride and pentaerythritol in a solvent and reacting them at 25° C. for 4 hours to generate pentaerythritol phosphoryl chloride; wherein the mass ratio of the solvent to phosphorus oxychloride is 30:1;

[0062] (3) adding ethanolamine and phenylethanol to the reaction system of step (2), and reacting at 35° C. for 2.5 hours to generate an intermediate product capped with ethanolamine at one end and capped with phenylethanol at the other end; wherein the molar ratio of pentaerythritol, phosphorus oxychloride, ethanolamine, and phenylethanol is 1:2:1:1;

[0063] (4) The intermediate product obtained in step (3) is added to water to obtain an intermediate product aqueous solution, the pH value of the intermediate product aqueous solution is adjusted to 7.5 with sodium carbonate, and then the aqueous solution is added to a cyanuric chloride aqueous dispersion to obtain a mixture, the mixture is stirred and reacted at a temperature of 0° C. for 4 hours, and after the reaction is completed, it is purified by reduced pressure distillation to obtain an active phosphate flame retardant; wherein the molar ratio of cyanuric chloride to the intermediate product is 1:1; and the mass ratio of water to cyanuric chloride in the mixture is 40:1.

[0064] The nuclear magnetic resonance hydrogen spectrum of the finally prepared active phosphate flame retardant is as follows Figure 2As shown, the chemical shifts at 4.2ppm and 3.1ppm are caused by the hydrogen elements in the ethanolamine structure, the chemical shift at 3.9ppm is caused by the hydrogen elements in the pentaerythritol structure, the chemical shift near 7.2ppm is caused by the hydrogen elements in the benzene ring of phenylethanol, the chemical shifts at 4.4ppm and 2.9ppm are caused by the hydrogen elements in the aliphatic chain segment of phenylethanol, and the chemical shift at 4.8ppm is caused by heavy water; the structural formula of the active phosphate flame retardant is:

[0065] .

[0066] An application of an active phosphate flame retardant, the steps are as follows:

[0067] (a) dissolving the above-prepared active phosphate flame retardant in water to obtain a flame retardant finishing liquid; in the flame retardant finishing liquid, the concentration of the active phosphate flame retardant is 175 g / L;

[0068] (b) adding a polyester / cotton blended fabric (polyester content of 80wt%, limiting oxygen index of 20.3%, and damaged length of 30cm) into a flame retardant finishing liquid and reacting at 85°C for 30min; wherein the bath ratio of the polyester / cotton blended fabric to the flame retardant finishing liquid is 1:30;

[0069] (c) adding sodium carbonate to the reaction system of step (b), adjusting the pH value of the reaction system to 8, maintaining the temperature constant, and continuing the reaction for 40 minutes;

[0070] (d) taking out the polyester / cotton blended fabric obtained in step (c), and sequentially performing rolling, pre-baking and baking to obtain a durable flame retardant polyester / cotton blended fabric; wherein the rolling rate is 95%, the pre-baking temperature is 65° C., the pre-baking time is 3 min, the baking temperature is 140° C., and the baking time is 4 min.

[0071] The resulting durable flame retardant polyester / cotton blended fabric had a limiting oxygen index of 30.2% and a damage length of 9.2 cm (e.g. Figure 3 As shown in the figure), after 40 washes, the damaged length is 14.7 cm.

[0072] Comparative Example 1

[0073] A flame retardant with the structural formula:

[0074] .

[0075] The preparation method of the flame retardant comprises the following steps:

[0076] (1) Phosphorus oxychloride, ethanolamine and phenylethanol are dissolved in a solvent (dimethyl sulfoxide) and reacted at 38°C for 3.5 hours to obtain an intermediate product; wherein the mass ratio of the solvent to phosphorus oxychloride is 35:1, and the molar ratio of phosphorus oxychloride, ethanolamine and phenylethanol is 1:1.1:2.1;

[0077] (2) The intermediate product obtained in step (1) is added to water to obtain an intermediate product aqueous solution, the pH value of the intermediate product aqueous solution is adjusted to 7 with sodium carbonate, and then the intermediate product aqueous solution is added to a cyanuric chloride aqueous dispersion to obtain a mixture, the mixture is stirred and reacted at a temperature of 3° C. for 3.5 hours, and after the reaction is completed, it is purified by reduced pressure distillation to obtain an active phosphate flame retardant; wherein the molar ratio of cyanuric chloride to the intermediate product is 1:1; and the mass ratio of water to cyanuric chloride in the mixture is 40:1.

[0078] The application of the flame retardant is basically the same as that in Example 1, except that the flame retardant used is prepared in this comparative example.

[0079] The final flame-retardant polyester / cotton blended fabric had a limiting oxygen index of 29.5%, a damaged length of 10.1 cm, and a damaged length of 30 cm after 40 washes.

[0080] By comparing Comparative Example 1 with Example 1, it can be seen that the limiting oxygen index of the flame-retardant polyester / cotton blended fabric prepared in Comparative Example 1 is significantly reduced, the damaged length is significantly increased, and it is completely burned after 40 water washings, and the water washing resistance is reduced. This is because although the flame retardant contains two benzene rings, its molecular chain segment is relatively short. After one benzene ring reacts with the polyester fiber, the other benzene ring is difficult to continue to combine with the polyester fiber, resulting in the inability of the two benzene rings to combine with the polyester fiber at the same time. Therefore, the flame retardant has limited ability to combine with polyester fibers and cotton fibers at the same time, resulting in reduced water washing resistance.

[0081] Example 2

[0082] A method for preparing an active phosphate flame retardant, comprising the following steps:

[0083] (1) Preparation of raw materials;

[0084] Phosphorus oxychloride;

[0085] Pentaerythritol;

[0086] Ethanolamine;

[0087] Phenylethyl alcohol;

[0088] Solvent: dimethyl sulfoxide;

[0089] Sodium carbonate;

[0090] Water: deionized water;

[0091] Cyanuric chloride;

[0092] (2) dissolving phosphorus oxychloride and pentaerythritol in a solvent and reacting them at 28° C. for 3.5 hours to generate pentaerythritol phosphoryl chloride; wherein the mass ratio of the solvent to phosphorus oxychloride is 40:1;

[0093] (3) adding ethanolamine and phenylethanol to the reaction system of step (2), reacting at 38° C. for 2 h to generate an intermediate product capped with ethanolamine at one end and capped with phenylethanol at the other end; wherein the molar ratio of pentaerythritol, phosphorus oxychloride, ethanolamine and phenylethanol is 1:2.1:1:1.1;

[0094] (4) The intermediate product obtained in step (3) is added to water to obtain an intermediate product aqueous solution, the pH value of the intermediate product aqueous solution is adjusted to 6.5 with sodium carbonate, and then the intermediate product aqueous solution is added to a cyanuric chloride aqueous dispersion to obtain a mixture, the mixture is stirred and reacted at a temperature of 2° C. for 3.7 hours, and after the reaction is completed, it is purified by reduced pressure distillation to obtain an active phosphate flame retardant; wherein the molar ratio of cyanuric chloride to the intermediate product is 1.05:1; and the mass ratio of water to cyanuric chloride in the mixture is 37:1.

[0095] An application of an active phosphate flame retardant, the steps are as follows:

[0096] (a) dissolving the above-prepared active phosphate flame retardant in water to obtain a flame retardant finishing liquid; in the flame retardant finishing liquid, the concentration of the active phosphate flame retardant is 200 g / L;

[0097] (b) adding a polyester / cotton blended fabric (polyester content of 50wt%, limiting oxygen index of 20.1%, and damaged length of 30cm) into a flame retardant finishing liquid and reacting at 99°C for 27min; wherein the bath ratio of the polyester / cotton blended fabric to the flame retardant finishing liquid is 1:35;

[0098] (c) adding sodium bicarbonate to the reaction system of step (b), adjusting the pH value of the reaction system to 8.5, maintaining the temperature constant, and continuing the reaction for 50 minutes;

[0099] (d) taking out the polyester / cotton blended fabric obtained in step (c), and sequentially performing rolling, pre-baking and baking to obtain a durable flame retardant polyester / cotton blended fabric; wherein the rolling rate is 100%, the pre-baking temperature is 69° C., the pre-baking time is 2.7 min, the baking temperature is 143° C., and the baking time is 3.7 min.

[0100] The final durable flame-retardant polyester / cotton blended fabric had a limiting oxygen index of 31.3%, a damaged length of 8.6 cm, and a damaged length of 14.2 cm after 40 washes.

[0101] Example 3

[0102] A method for preparing an active phosphate flame retardant, comprising the following steps:

[0103] (1) Preparation of raw materials;

[0104] Phosphorus oxychloride;

[0105] Pentaerythritol;

[0106] Ethanolamine;

[0107] Phenylethyl alcohol;

[0108] Solvent: dimethyl sulfoxide;

[0109] Sodium carbonate;

[0110] Water: deionized water;

[0111] Cyanuric chloride;

[0112] (2) dissolving phosphorus oxychloride and pentaerythritol in a solvent and reacting them at 30° C. for 3 hours to generate pentaerythritol phosphoryl chloride; wherein the mass ratio of the solvent to phosphorus oxychloride is 35:1;

[0113] (3) adding ethanolamine and phenylethanol to the reaction system of step (2), and reacting at 40° C. for 1.5 h to generate an intermediate product capped with ethanolamine at one end and capped with phenylethanol at the other end; wherein the molar ratio of pentaerythritol, phosphorus oxychloride, ethanolamine, and phenylethanol is 1:2.2:1:1.2;

[0114] (4) The intermediate product obtained in step (3) is added to water to obtain an intermediate product aqueous solution, the pH value of the intermediate product aqueous solution is adjusted to 7 with sodium carbonate, and then the intermediate product aqueous solution is added to a cyanuric chloride aqueous dispersion to obtain a mixture, the mixture is stirred and reacted at a temperature of 4° C. for 3.4 hours, and after the reaction is completed, it is purified by reduced pressure distillation to obtain an active phosphate flame retardant; wherein the molar ratio of cyanuric chloride to the intermediate product is 1.1:1; and the mass ratio of water to cyanuric chloride in the mixture is 34:1.

[0115] An application of an active phosphate flame retardant, the steps are as follows:

[0116] (a) dissolving the above-prepared active phosphate flame retardant in water to obtain a flame retardant finishing liquid; in the flame retardant finishing liquid, the concentration of the active phosphate flame retardant is 225 g / L;

[0117] (b) adding a polyester / cotton blended fabric (polyester content of 20 wt%, limiting oxygen index of 20.0%, and damaged length of 30 cm) into a flame retardant finishing liquid and reacting at 93°C for 24 min; wherein the bath ratio of the polyester / cotton blended fabric to the flame retardant finishing liquid is 1:40;

[0118] (c) adding sodium carbonate to the reaction system of step (b), adjusting the pH value of the reaction system to 7.5, maintaining the temperature constant, and continuing the reaction for 55 minutes;

[0119] (d) taking out the polyester / cotton blended fabric obtained in step (c), and sequentially performing rolling, pre-baking and baking to obtain a durable flame retardant polyester / cotton blended fabric; wherein the rolling rate is 90%, the pre-baking temperature is 73° C., the pre-baking time is 2.4 min, the baking temperature is 147° C., and the baking time is 3.4 min.

[0120] The final durable flame-retardant polyester / cotton blended fabric had a limiting oxygen index of 31.9% and a damaged length of 8.3 cm. After 40 washes, the damaged length was 13.8 cm.

[0121] Example 4

[0122] A method for preparing an active phosphate flame retardant, comprising the following steps:

[0123] (1) Preparation of raw materials;

[0124] Phosphorus oxychloride;

[0125] Pentaerythritol;

[0126] Ethanolamine;

[0127] Phenylethyl alcohol;

[0128] Solvent: dimethyl sulfoxide;

[0129] Sodium carbonate;

[0130] Water: deionized water;

[0131] Cyanuric chloride;

[0132] (2) dissolving phosphorus oxychloride and pentaerythritol in a solvent and reacting them at 26° C. for 3.7 hours to generate pentaerythritol phosphoryl chloride; wherein the mass ratio of the solvent to phosphorus oxychloride is 40:1;

[0133] (3) adding ethanolamine and phenylethanol to the reaction system of step (2), reacting at 36° C. for 2.3 h to generate an intermediate product capped with ethanolamine at one end and capped with phenylethanol at the other end; wherein the molar ratio of pentaerythritol, phosphorus oxychloride, ethanolamine and phenylethanol is 1:2.2:1:1;

[0134] (4) The intermediate product obtained in step (3) is added to water to obtain an intermediate product aqueous solution, the pH value of the intermediate product aqueous solution is adjusted to 6.5 with sodium carbonate, and then the intermediate product aqueous solution is added to a cyanuric chloride aqueous dispersion to obtain a mixture, the mixture is stirred and reacted at a temperature of 5° C. for 3 h, and after the reaction is completed, it is purified by reduced pressure distillation to obtain an active phosphate flame retardant; wherein the molar ratio of cyanuric chloride to the intermediate product is 1:1; and the mass ratio of water to cyanuric chloride in the mixture is 30:1.

[0135] An application of an active phosphate flame retardant, the steps are as follows:

[0136] (a) dissolving the above-prepared active phosphate flame retardant in water to obtain a flame retardant finishing liquid; in the flame retardant finishing liquid, the concentration of the active phosphate flame retardant is 250 g / L;

[0137] (b) adding a polyester / cotton blended fabric (polyester content of 25wt%, limiting oxygen index of 20.1%, and damaged length of 30cm) into a flame retardant finishing liquid and reacting at 95°C for 20min; wherein the bath ratio of the polyester / cotton blended fabric to the flame retardant finishing liquid is 1:35;

[0138] (c) adding sodium bicarbonate to the reaction system of step (b), adjusting the pH value of the reaction system to 7.9, maintaining the temperature constant, and continuing the reaction for 60 minutes;

[0139] (d) taking out the polyester / cotton blended fabric obtained in step (c), and sequentially performing rolling, pre-baking and baking to obtain a durable flame retardant polyester / cotton blended fabric; wherein the rolling rate is 95%, the pre-baking temperature is 75° C., the pre-baking time is 2 min, the baking temperature is 150° C., and the baking time is 3 min.

[0140] The final durable flame retardant polyester / cotton blended fabric had a limiting oxygen index of 32.5%, a damaged length of 8.0 cm, and a damaged length of 13.5 cm after 40 washes.

Claims

1. An active phosphate flame retardant, characterized in that: The structural formula is as follows:

2. A method for preparing an active phosphate flame retardant as claimed in claim 1, characterized in that: The following steps are involved: (1) reacting phosphorus oxychloride with pentaerythritol to generate pentaerythritol phosphoryl chloride; (2) reacting ethanolamine and phenylethanol with pentaerythritol phosphoryl chloride to generate an intermediate product capped with ethanolamine at one end and capped with phenylethanol at the other end; (3) The intermediate product is reacted with cyanuric chloride to generate an active phosphate flame retardant.

3. The method according to claim 2, characterized in that In steps (1) to (3), the molar ratio of pentaerythritol, phosphorus oxychloride, ethanolamine and phenylethanol is 1:2 to 2.2:1:1 to 1.2, and the molar ratio of cyanuric chloride to the intermediate product is 1 to 1.1:

1.

4. The method according to claim 2, characterized in that: In step (1), the reaction temperature is 25-30°C and the reaction time is 3-4h; in step (2), the reaction temperature is 35-40°C and the reaction time is 1.5-2.5h; in step (3), the reaction temperature is 0-5°C and the reaction time is 3-4h.

5. The method according to claim 2, characterized in that: The specific process is as follows: (a) dissolving phosphorus oxychloride and pentaerythritol in a solvent, reacting to generate pentaerythritol phosphoryl chloride; (b) adding ethanolamine and phenylethanol to the reaction system of step (a), reacting to generate an intermediate product having one end capped with ethanolamine and the other end capped with phenylethanol; (c) adding the intermediate product obtained in step (b) into water to obtain an intermediate product aqueous solution, adjusting the pH value of the intermediate product aqueous solution to 6.5-7.5, adding the intermediate product aqueous solution into a cyanuric chloride aqueous dispersion to obtain a mixture, stirring the mixture to react, and generating an active phosphate flame retardant.

6. The method according to claim 5, characterized in that In step (a), the mass ratio of the solvent to phosphorus oxychloride is 30 to 40:1; in step (c), in the mixture, the mass ratio of water to cyanuric chloride is 30 to 40:

1.

7. The use of an active phosphate flame retardant as claimed in claim 1, characterized in that: Used for flame retardant finishing of polyester / cotton blended fabrics.

8. The use according to claim 7, characterized in that: The specific process is: dissolving the active phosphate flame retardant in water to obtain a flame retardant finishing liquid, adding the polyester / cotton blended fabric to the flame retardant finishing liquid, reacting at 85-99°C for 30 minutes, then adding an alkali agent to adjust the pH value of the system to 7.5-8.5 and reacting for 40-60 minutes, taking out the polyester / cotton blended fabric, and rolling, pre-baking and baking in sequence to obtain a flame retardant polyester / cotton blended fabric.

9. The use according to claim 8, characterized in that: In the flame retardant finishing liquid, the concentration of active phosphate flame retardant is 175-250g / L; In polyester / cotton blended fabrics, the content of polyester is 20-80wt%; The bath ratio of polyester / cotton blended fabric to flame retardant finishing liquid is 1:30-40; The rolling rate of rolling is 90-100%; The pre-baking temperature is 65-75°C and the pre-baking time is 2-3 minutes; The baking temperature is 140-150°C, and the baking time is 3-4 minutes.

10. The use according to claim 9, characterized in that: The limiting oxygen index of the flame-retardant polyester / cotton blended fabric is higher than 30.2%, the damaged length is lower than 9.2 cm, and the damaged length is still lower than 14.7 cm after 40 washes.

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