Preparation method, product and application of alkylamine boric acid phosphoric acid modified meglumine flame retardant

Abstract

The present invention provides a preparation method, product and application of an alkylamine boric acid phosphoric acid modified meglumine flame retardant. In the preparation method, meglumine is used as a matrix, phosphoric acid and boric acid are added successively to carry out esterification reaction with meglumine, thereby improving the flame retardant performance of phosphorylated meglumine; and urea and alkylamine are added simultaneously to modify the boric acid phosphorylated meglumine, and the hydrophobic force of alkylamine is used to improve the adhesion of the flame retardant to the fabric surface, so that a smaller amount of the flame retardant can achieve better flame retardant performance, thereby reducing the amount of the flame retardant. Durable flame retardant finishing is used to give cotton fabrics excellent flame retardancy and flame retardant durability. The preparation method is simple, the raw material price is low, the processing equipment requirements are low, the reproducibility is good, and it is conducive to industrial production.

Description

Technical Field

[0001] The invention belongs to the field of textile technology, and specifically relates to a preparation method, a product and an application of an alkylamine boric acid phosphoric acid modified meglumine flame retardant. Background Art

[0002] Cotton fabrics have excellent properties such as good hygroscopicity, skin-friendly and soft, and easy to degrade, and have always been loved by consumers. They have broad application prospects in the fields of clothing, medical treatment, packaging, and home furnishing. However, the LOI of cotton fabrics is about 18%, which is very easy to burn, posing a major hidden danger to people's life safety and property. Therefore, it is necessary to develop new flame retardants to perform flame retardant finishing on them and improve their flame retardant properties.

[0003] Flame retardants for cotton are divided into three categories: organic, inorganic, and organic-inorganic composites. Organic flame retardants have the following characteristics: (1) Low dosage and excellent flame retardant performance. (2) Easy covalent grafting to achieve flame retardant durability. With the improvement of environmental awareness, the development of green and environmentally friendly biomass-based textile flame retardants is the focus of current research.

[0004] Derived from glucose, meglumine is an amino sugar that is often used in the pharmaceutical, food and cosmetic fields. It has the advantages of high safety and biodegradability. In addition, meglumine is easy to obtain, contains nitrogen, and has many hydroxyl functional groups for chemical modification, making it a good flame retardant modification matrix.

[0005] Esterification of phosphoric acid and polyols is a popular method for preparing flame retardants. This method can not only select biomass polyols to meet environmental protection requirements, but also use active ammonium phosphate groups to give cotton fabrics washability. However, studies have shown that in the synthesis process of phosphate ester polyols, the efficiency of phosphate esterification is low and it is difficult to have efficient flame retardant properties. Some researchers have used phosphoric acid and sorbitol to prepare sorbitol-based flame retardants with a yield of 66%.

[0006] In order to further enhance the flame retardant effect of phosphorus-nitrogen flame retardants, boron-phosphorus-nitrogen synergistic flame retardant can be used. Boron-based flame retardants mainly include inorganic borates such as zinc borate, borax, calcium metaborate, sodium metaborate, and a few organic boric acid vinegars, which have the advantages of good thermal stability, low toxicity, smoke elimination, low toxicity, and easy availability of raw materials. It has been reported that boron-based flame retardants can be compounded with nitrogen-based or phosphorus-based flame retardants to achieve a synergistic flame retardant effect. However, due to the water solubility of flame retardants, a high concentration of flame retardant finishing liquid needs to be prepared during the finishing process to meet the flame retardant performance, which is difficult to meet the requirements of high efficiency. Summary of the invention

[0007] In order to solve the problems existing in the prior art, the present invention provides a preparation method, product and application of an efficient and durable alkylamine boric acid phosphoric acid modified meglumine flame retardant. The preparation method is based on the idea of ​​boron, phosphorus and nitrogen synergistic flame retardancy and the hydrophobic modification strategy. Phosphoric acid and boric acid are first used to react with the hydroxyl groups on meglumine in turn for esterification, and then urea and alkylamine are used to modify the esterified product at the same time. While improving the flame retardant effect of the flame retardant, the hydrophilicity of the flame retardant is reduced, the flame retardant efficiency is improved, and the use cost is reduced. The alkylamine boric acid phosphoric acid modified meglumine flame retardant prepared by the preparation method of the present invention has excellent flame retardant properties and flame retardant durability, has the characteristics of high efficiency and durability, and the preparation method is simple and convenient, has low requirements for processing equipment, good reproducibility, and is conducive to industrial production.

[0008] Hydrophobic modification of flame retardants is a good modification method. Alkylamine is an amine containing a carbon chain. The longer the carbon chain, the worse the water solubility. Alkylamine is aminated with phosphoric acid in the flame retardant, and the hydrophobicity of alkylamine is used to reduce the water solubility of the flame retardant. The hydrophobic force is used to improve the adhesion of the flame retardant to the fabric surface, thereby achieving the purpose of high-efficiency flame retardancy.

[0009] A method for preparing an alkylamine boric acid phosphoric acid modified meglumine flame retardant comprises the following steps:

[0010] (1) meglumine and phosphoric acid react in a solvent to obtain solution A;

[0011] (2) adding boric acid to solution A to react and obtain solution B;

[0012] (3) adding urea and alkylamine to solution B for reaction, and obtaining the alkylamine boric acid phosphoric acid modified meglumine flame retardant after the reaction is completed.

[0013] The reaction process in the above preparation method is as follows:

[0014]

[0015] However, due to the low efficiency of phosphation, not all R

[0016] n=3~12.

[0017] Phosphoric acid first undergoes an esterification reaction with part of the hydroxyl groups on meglumine to prepare phosphorylated meglumine; after adding boric acid, boric acid undergoes an esterification reaction with all or part of the hydroxyl groups on the phosphorylated meglumine to obtain boric acid phosphorylated meglumine; and then urea and alkylamine are added to react to prepare ammonium phosphate salt and / or alkylamine phosphate salt, i.e., alkylamine boric acid phosphoric acid modified meglumine flame retardant.

[0018] Preferably, the molar ratio of meglumine to phosphoric acid is 1:(3-10). Due to the low efficiency of phosphoric acid esterification, adding too much phosphoric acid does not improve its esterification rate, but increases the cost and the occurrence of side reactions. Therefore, as a further preference, the molar ratio of meglumine to phosphoric acid is 1:5.

[0019] Preferably, the molar ratio of meglumine to boric acid is 1:(1-5), more preferably 1:(3-5), and even more preferably 1:(3.5-4.5).

[0020] Preferably, the molar ratio of phosphoric acid to urea is 1:(0.01 to 0.9), more preferably 1:(0.2 to 0.8), and even more preferably 1:(0.4 to 0.8).

[0021] Preferably, the number of moles of alkylamine added is twice the difference between the number of moles of phosphoric acid and the number of moles of urea. 磷酸 -n 尿素 )×2; where n is the number of moles.

[0022] Preferably, in step (1), the reaction temperature of meglumine and phosphoric acid is 120-140°C, and the reaction time is 1-3 hours. More preferably, the reaction temperature is 125-135°C, and the reaction time is 1.5-2 hours.

[0023] Preferably, the solvent is one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and dichloromethane, and more preferably an anhydrous N,N-dimethylformamide (DMF) solution.

[0024] Preferably, in step (2), the reaction temperature after adding boric acid is 110-150°C, and the reaction time is 1-3 hours. More preferably, the reaction temperature is 110-140°C, and the reaction time is 1.5-2.5 hours. More preferably, the reaction temperature is 125-140°C.

[0025] Preferably, in step (3), the reaction temperature after adding urea and alkylamine is 110-130°C, and the reaction time is 0.5-2h. More preferably, the reaction temperature is 115-125°C, and the reaction time is 0.5-1.5h.

[0026] Preferably, the alkylamine is one or more of n-propylamine, n-butylamine, n-pentylamine, n-hexylamine, heptylamine, octylamine, and dodecylamine. More preferably, it is one or two of n-propylamine, n-butylamine, and n-pentylamine. More preferably, it is one of n-propylamine and n-butylamine.

[0027] Preferably, in step (3), after the reaction is completed, the following post-treatment is performed:

[0028] The reaction product is washed with ethanol for several times to remove unreacted raw materials, and then dried at 60-80° C. to obtain the alkylamine boric acid phosphoric acid modified meglumine flame retardant.

[0029] An alkylamine boric acid phosphoric acid modified meglumine flame retardant is prepared by any of the above-mentioned preparation methods.

[0030] The present invention also provides a durable flame retardant finishing liquid, which is an aqueous solution of the alkylamine boric acid phosphoric acid modified meglumine flame retardant and a catalyst dicyandiamide.

[0031] The durable flame retardant finishing liquid is applied to the flame retardant finishing of cotton fabrics. The cotton fabrics after the flame retardant finishing can have good flame retardancy and flame retardant durability, and have broad application prospects. When dicyandiamide is used as a catalyst, the ammonium phosphate group can be catalyzed to form phosphoric anhydride, and the phosphoric anhydride reacts with the hydroxyl group on the cellulose to undergo an esterification reaction. The flame retardant and the fiber are covalently bonded, which can effectively improve the flame retardant durability of the finished fabric and achieve durable finishing.

[0032] Preferably, the durable flame retardant finishing liquid is prepared as follows:

[0033] The alkylamine boric acid and phosphoric acid modified meglumine flame retardant is dissolved in water to prepare an aqueous solution, dicyandiamide is added as a catalyst to the prepared aqueous solution, and the mixture is stirred evenly to obtain the durable flame retardant finishing liquid.

[0034] Preferably, in the durable flame retardant finishing liquid, the concentration of the alkylamine boric acid phosphoric acid modified meglumine flame retardant is 10 to 200 g / L, more preferably 30 to 100 g / L.

[0035] Preferably, the mass concentration of dicyandiamide in the durable flame retardant finishing liquid is 4 to 10 wt %, more preferably 4 to 8 wt %, and even more preferably 4 to 6 wt %.

[0036] A use of the above-mentioned durable flame retardant finishing liquid in durable flame retardant finishing of cotton fabrics.

[0037] Specifically, the cotton fabric is immersed in the durable flame retardant finishing liquid for padding, and after the padding is completed, the fabric is taken out for drying and baking to obtain the durable flame retardant cotton fabric.

[0038] The cotton fabric finished with the durable flame retardant finishing liquid of the present invention has excellent flame retardancy and flame retardant durability.

[0039] During the flame retardant finishing process:

[0040] Preferably, the bath ratio of cotton fabric to durable flame retardant finishing liquid is 1:(10-30).

[0041] Preferably, the immersion temperature is 40 to 80° C., and the immersion time is 10 to 50 min. More preferably, the immersion temperature is 60 to 80° C., and the immersion time is 20 to 40 min.

[0042] Preferably, the dipping and rolling method is double dipping and double rolling, and the rolling ratio is 90 to 100%.

[0043] Preferably, the drying temperature is 60-90° C., and the drying time is 4-6 minutes.

[0044] Preferably, the baking temperature is 150-180° C., and the baking time is 3-6 minutes.

[0045] Preferably, before baking, the padding and drying process is repeated 1 to 2 times.

[0046] The preparation method of the present invention further improves the flame retardant performance of phosphorylated meglumine through the esterification reaction of boric acid, ingeniously utilizes the ion reaction of alkylamine and phosphoric acid to reduce the water solubility of the flame retardant, and prepares an alkylamine boric acid phosphoric acid modified meglumine flame retardant. The flame retardant can achieve good flame retardant performance with a small amount, reduces the amount of the flame retardant, and gives cotton fabrics excellent flame retardancy and flame retardant durability through durable flame retardant finishing.

[0047] The preparation method of the alkylamine boric acid phosphoric acid modified meglumine flame retardant of the present invention takes meglumine as a matrix, successively adds phosphoric acid and boric acid to meglumine for esterification reaction, thereby improving the flame retardant performance of phosphorylated meglumine; and simultaneously adds urea and alkylamine to modify the boric acid phosphorylated meglumine, utilizes the hydrophobic force of alkylamine to improve the adhesion of the flame retardant to the surface of the fabric, thereby reducing the usage amount of the flame retardant, and the prepared alkylamine boric acid phosphoric acid modified meglumine flame retardant has excellent flame retardant performance and flame retardant durability.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The preparation method of the present invention simultaneously adds urea and alkylamine to react with boric acid phosphorylated meglumine, and the amino group of the alkylamine can react with the phosphoric acid in the boric acid phosphorylated meglumine to reduce the water solubility of the flame retardant; the prepared flame retardant can impart high-efficiency flame retardant effect to cotton fabrics at a low dosage; compared with boric acid phosphorylated meglumine modified with urea alone, when the LOI of cotton fabrics treated with the durable flame retardant finishing liquid reaches more than 36%, the concentration of the alkylamine boric acid phosphorylated meglumine flame retardant only needs to be 75 g / L, while the concentration of the boric acid phosphorylated meglumine modified with urea alone needs to be 200 g / L.

[0050] (2) The raw materials used in the present invention are low in price, the preparation method is simple and convenient, the reaction conditions are mild, the controllability is strong, the reproducibility is good, and it has broad application prospects.

[0051] (3) After washing 30 times, the durable flame retardant cotton fabric treated with the durable flame retardant finishing liquid provided by the present invention still has a LOI of more than 30%, which is reduced by less than 25%. It has excellent flame retardancy and durability and meets the requirements of durable finishing. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The dissolution of different flame retardants prepared with different alkyl amines into a finishing liquid with a concentration of 200 g / L; among them, the alkyl amines from left to right are n-propylamine, n-butylamine, n-pentylamine, octylamine, and dodecylamine. DETAILED DESCRIPTION

[0053] Below in conjunction with specific embodiment, further elaborate technical scheme of the present invention.It should be understood that these embodiments are only used to illustrate technical scheme of the present invention and are not used to limit the scope of the present invention.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 also fall within the scope limited by the appended claims of the application.

[0054] Example 1: Selection of alkylamines

[0055] (1) 6 portions of 75 mL DMF were placed in 6 flasks for standby use, 0.05 mol of meglumine and 0.25 mol of phosphoric acid were added to 6 portions of DMF, and the mixture was reacted at 130°C for 2 h. Subsequently, 0.20 mol of boric acid was added to the six flasks, and the mixture was reacted at 130°C for 2 h to obtain boric acid phosphorylated meglumine. Finally, 0.25 mol of urea was added to one of the flasks, and 0.15 mol of urea and 0.20 mol of alkylamine (n-propylamine, n-butylamine, n-pentylamine, octylamine, and dodecylamine) were added to the remaining 5 flasks, and the mixture was reacted at 120°C for 1 h. The reaction product was washed with ethanol several times and dried at 80°C to obtain 6 alkylamine boric acid phosphoric acid modified meglumine flame retardants, which were respectively recorded as 1#, 2#, 3#, 4#, 5#, and 6# flame retardants.

[0056] (2) Each of the above six alkylamine boric acid phosphoric acid modified meglumine flame retardants was prepared into 25 g / L, 50 g / L, 75 g / L, 100 g / L, and 200 g / L aqueous solutions for standby use. 6 wt% of dicyandiamide was added as a catalyst to the prepared aqueous solutions to obtain 30 flame retardant finishing solutions.

[0057] (3) 30 pieces of cotton fabrics were immersed in the 30 flame retardant finishing liquids prepared one by one, the immersion temperature was 70°C, the immersion time was 30 min, the bath ratio was 1:20, two immersions and two paddings were performed, the liquid carrying rate was kept at 100%, and the immersion and padding drying process was repeated at 80°C for 3 min, and the immersion and padding drying process was repeated once, and the immersion and padding drying process was repeated at 170°C for 5 min. 30 different flame retardant cotton fabrics were obtained.

[0058] In order to explore the influence of the type of alkylamine and the concentration of flame retardant on the flame retardant properties of flame retardant, the limiting oxygen index (LOI, unit %) of the 30 flame retardant cotton fabrics prepared above was tested respectively (reference standard is GB / T5454-1997 "Determination of Combustion Performance of Textiles-Oxygen Index Determination Method"), and the results are shown in Table 1.

[0059] Table 1 Effects of different alkylamine types and flame retardant concentrations on LOI of flame retardant-finished cotton fabrics

[0060]

[0061] As shown in Table 1, compared with the flame retardant 1# without alkylamine, the addition of alkylamine in the flame retardants 2# to 4# can effectively reduce the amount of flame retardant. This is because the alkyl chain is hydrophobic. The introduction of the alkyl chain in the flame retardant reduces the water solubility of the flame retardant and enhances the hydrophobic force of the flame retardant, making it easier to adhere to the fabric during the finishing process, and can achieve a better flame retardant effect at a lower concentration. At the same concentration of flame retardant, the flame retardant (2#) made from n-propylamine has the best flame retardant performance. The longer the alkyl chain, the lower the flame retardant performance. Among them, the flame retardant performance of 5# (octylamine) and 6# (dodecylamine) flame retardants is worse than that of 1# flame retardant. This may be because the alkyl chain has no flame retardant effect. Due to its flammability, it will reduce the LOI of cotton fabrics. Moreover, the longer the alkyl chain, the less the proportion of flame retardant elements in the flame retardant. The comprehensive factors lead to the reduction of flame retardant performance.

[0062] Figure 1 The figure shows the dissolution of different types of alkylamine boric acid phosphoric acid modified meglumine flame retardants in the solution when they are prepared into a flame retardant finishing liquid with a concentration of 200g / L. Figure 1 It can be seen that the longer the alkyl chain of the selected alkylamine, the stronger the hydrophobicity of the prepared flame retardant and the worse the solubility.

[0063] In order to detect the flame retardant washing resistance (flame retardant durability) of flame retardant cotton fabrics, the flame retardant cotton fabrics finished with a flame retardant finishing liquid with a concentration of 200g / L of 2# flame retardant were tested for washing resistance (reference standard is AATCC 61-2013 Color fastness to washing: accelerated method, and one wash is equivalent to 5 home washes). The flame retardant durability of flame retardant cotton fabrics was evaluated by the LOI value after 5, 10, 15, 15, 20, 25, and 30 home washes. The results are shown in Table 2.

[0064] Table 2 Effect of different washing times on LOI of flame retardant cotton fabrics

[0065] Washing times LOI / % 5 39.2 10 38.1 15 37.2 20 35.9 25 34.5 30 33.4

[0066] It can be seen from Table 2 that after 30 home washes, the LOI of the flame retardant cotton fabric is still greater than 30%, which has excellent flame retardant durability.

[0067] By comparing 1#, 2# and 3# flame retardants, it can be found that when the LOI of cotton fabric reaches more than 36%, the flame retardant concentration of 200g / L is required to prepare the flame retardant finishing liquid with 1# flame retardant without adding alkylamine, while the flame retardant finishing liquid prepared with 2# and 3# flame retardants only requires 75g / L, which significantly reduces the dosage, effectively improves the flame retardant efficiency and reduces the cost.

[0068] Example 2: Selection of Boric Acid Reaction Temperature

[0069] (1) 5 portions of 75 mL DMF were placed in five flasks for standby use, 0.05 mol of meglumine and 0.25 mol of phosphoric acid were added to the 5 portions of DMF, and the mixture was reacted at 130°C for 2 h. Subsequently, 0.2 mol of boric acid was added to the 5 flasks, and the mixture was reacted at 110°C, 120°C, 130°C, 140°C, and 150°C for 2 h. Finally, 0.15 mol of urea and 0.2 mol of n-propylamine were added to the five flasks, and the mixture was reacted at 120°C for 1 h. The reaction products were washed with ethanol several times and dried at 80°C to obtain 5 alkylamine boric acid phosphoric acid modified meglumine flame retardants.

[0070] (2) The above five alkylamine boric acid and phosphoric acid modified meglumine flame retardants were prepared into 75 g / L aqueous solutions for use. 6 wt % of dicyandiamide was added to the prepared aqueous solutions as a catalyst.

[0071] (3) Five cotton fabrics were immersed in the prepared flame retardant finishing liquid one by one, the immersion temperature was 70°C, the immersion time was 30 min, the bath ratio was 1:20, two immersions and two paddings were performed, the liquid carrying rate was kept at 100%, and the immersion and padding drying process was repeated once, and the immersion and padding drying process was repeated at 170°C for 5 min. Five different flame retardant cotton fabrics were obtained.

[0072] The limiting oxygen index (LOI) of the above 5 flame retardant cotton fabrics was tested, and the results are shown in Table 2.

[0073] Table 3 Effect of different reaction temperatures on the flame retardant properties of cotton fabrics treated with flame retardants

[0074] Boric acid reaction temperature / ℃ LOI / % 110 33.4 120 34.8 130 36.9 140 36.8 150 36.7

[0075] Since the esterification reaction is a reversible reaction, the generated water needs to be continuously removed from the reaction system to promote the forward reaction, so the reaction temperature cannot be too low, so the effect of temperature on the LOI value was investigated in the range of 110-150°C. As shown in Table 2, when the temperature is low, the reaction is incomplete. As the reaction temperature increases, the LOI value increases and the degree of reaction increases; but when the temperature is too high, the viscosity of the system increases rapidly, affecting the subsequent reaction, and some side reactions will occur in the system, affecting the LOI value, so it is more appropriate to choose a temperature of 130°C.

[0076] Example 3: Selection of n-propylamine dosage (selection of phosphoric acid to urea molar ratio)

[0077] (1) 5 portions of 75 mL DMF were placed in five flasks for standby use, 0.05 mol of meglumine and 0.25 mol of phosphoric acid were added to the 5 portions of DMF, and the mixture was reacted at 130°C for 2 h. Subsequently, 0.2 mol of boric acid was added to the 5 flasks, and the mixture was reacted at 130°C for 2 h. Finally, urea and n-propylamine (0.2 mol of urea and 0.1 mol of n-propylamine, 0.15 mol of urea and 0.2 mol of n-propylamine, 0.1 mol of urea and 0.3 mol of n-propylamine, 0.05 mol of urea and 0.4 mol of n-propylamine, 0.5 mol of n-propylamine) were added to the five flasks, and the mixture was reacted at 120°C for 1 h. The reaction product was washed with ethanol several times and dried at 80°C to obtain 5 alkylamine boric acid phosphoric acid modified meglumine flame retardants.

[0078] (2) The above five alkylamine boric acid and phosphoric acid modified meglumine flame retardants were prepared into 75 g / L aqueous solutions for use. 6 wt % of dicyandiamide was added to the prepared aqueous solutions as a catalyst.

[0079] (3) Five cotton fabrics were immersed in the prepared flame retardant finishing liquid one by one, the immersion temperature was 70°C, the immersion time was 30 min, the bath ratio was 1:20, two immersions and two rollings were performed, the liquid carrying rate was kept at 100%, and the fabrics were dried at 80°C for 3 min. The immersion, rolling and drying process was repeated once, and the fabrics were baked at 170°C for 5 min to obtain five different flame retardant cotton fabrics, which were respectively recorded as A, B, C, D, and E.

[0080] The limiting oxygen index (LOI) of 5 flame retardant cotton fabrics was tested, and the results are shown in Table 4.

[0081] Table 4 Effect of different n-propylamine dosage on LOI of flame retardant finished cotton fabric

[0082] Flame retardant cotton fabric number LOI / % A 35.2 B 36.9 C 34.8 D 33.2 E 31.9

[0083] As can be seen from Table 4, the flame retardant cotton fabric B (the molar ratio of phosphoric acid to urea is 1:0.6) has the highest limiting oxygen index and the best flame retardant performance. The LOI of flame retardant cotton fabric A (the molar ratio of phosphoric acid to urea is 1:0.8) is slightly worse than that of B, which may be due to the excessive use of urea, resulting in less use of n-propylamine, less hydrophobic modification of the flame retardant, and the lower concentration of the configured flame retardant finishing liquid, resulting in a slightly worse final flame retardant effect. The flame retardant performance of flame retardant cotton fabrics C, D and E (the molar ratio of phosphoric acid to urea is 1:0.4, 1:0.2 and no urea) is worse than that of B, which may be due to the use of less or no urea, and the use of more n-propylamine, which is not flame retardant and flammable, so the flame retardant performance of the flame retardant prepared is reduced.

[0084] Example 4: Selection of molar ratio of meglumine to boric acid

[0085] (1) 6 portions of 75 mL DMF were placed in 6 flasks for standby use, 0.05 mol of meglumine and 0.25 mol of phosphoric acid were added to the 6 portions of DMF, and the mixture was reacted at 130°C for 2 h. Boric acid (wherein the molar mass of boric acid was 0 mol, 0.05 mol, 0.10 mol, 0.15 mol, 0.20 mol, and 0.25 mol) was then added to the six flasks, and the reaction was continued at 130°C for 2 h to obtain boric acid phosphorylated meglumine. Finally, 0.15 mol of urea and 0.2 mol of n-propylamine were added to the six flasks, and the mixture was reacted at 120°C for 1 h. The reaction product was washed with ethanol several times and dried at 80°C to obtain 6 alkylamine boric acid phosphoric acid modified meglumine flame retardants.

[0086] (2) The above six alkylamine boric acid and phosphoric acid modified meglumine flame retardants were prepared into 75 g / L aqueous solutions for standby use. 6 wt% dicyandiamide was added as a catalyst to the prepared six aqueous solutions to obtain six flame retardant finishing solutions.

[0087] (3) Six cotton fabrics were immersed in the six flame retardant finishing liquids one by one, with an immersion temperature of 70°C, an immersion time of 30 min, a bath ratio of 1:20, two immersions and two paddings, with the liquid rate maintained at 100%, and baked at 80°C for 3 min, and the immersion and padding and drying process was repeated once, and baked at 170°C for 5 min. Six different flame retardant cotton fabrics were obtained.

[0088] The limiting oxygen index (LOI) test was performed on the 6 cotton fabrics obtained. The results are shown in Table 5.

[0089] Table 5 Effect of different molar ratios of meglumine to boric acid on LOI of flame retardant cotton fabrics

[0090] Molar ratio of meglumine to boric acid LOI / % 1:0 29.9 1:1 31.3 1:2 32.6 1:3 34.4 1:4 36.9 1:5 36.7

[0091] It can be seen from Table 5 that the addition of boric acid can improve the flame retardant properties of the flame retardant, and with the increase in the amount of boric acid, the LOI of the finished cotton fabric increases accordingly. When the molar ratio of meglumine to boric acid is 1:4, the LOI reaches a maximum of 36.9%. When too much boric acid is added (the molar ratio of meglumine to boric acid is 1:5), the degree of side reactions in the system increases, resulting in a slight decrease in the LOI value.

Claims

1. A method for preparing an alkylamine boric acid phosphoric acid modified meglumine flame retardant, characterized in that: The following steps are involved: (1) meglumine and phosphoric acid react in a solvent to obtain solution A; (2) adding boric acid to solution A to react and obtain solution B; (3) adding urea and alkylamine to solution B for reaction, and obtaining the alkylamine boric acid phosphoric acid modified meglumine flame retardant after the reaction is completed; The molar ratio of meglumine to phosphoric acid is 1:(3-10); The reaction temperature of meglumine and phosphoric acid is 120-140°C; The molar ratio of meglumine to boric acid is 1:(1-5); The molar ratio of phosphoric acid to urea is 1:(0.01-0.9); The number of moles of alkylamine added is twice the difference between the moles of phosphoric acid and urea; In step (2), the reaction temperature after adding boric acid is 110 to 150° C.; In step (3), the reaction temperature after adding urea and alkylamine is 110-130°C; The alkylamine is one or more of n-propylamine, n-butylamine, n-pentylamine, n-hexylamine, heptylamine, octylamine and dodecylamine.

2. The method for preparing the alkylamine boric acid phosphoric acid modified meglumine flame retardant according to claim 1, characterized in that: In step (1), the reaction time of meglumine and phosphoric acid is 1 to 3 hours; The solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide and dichloromethane.

3. The method for preparing the alkylamine boric acid phosphoric acid modified meglumine flame retardant according to claim 1, characterized in that: In step (2), the reaction time after adding boric acid is 1 to 3 hours.

4. The method for preparing the alkylamine boric acid phosphoric acid modified meglumine flame retardant according to claim 1, characterized in that: In step (3), the reaction time after adding urea and alkylamine is 0.5 to 2 hours.

5. An alkylamine boric acid phosphoric acid modified meglumine flame retardant, characterized in that: The method is prepared according to any one of claims 1 to 4.

6. A durable flame retardant finishing liquid, characterized in that: The durable flame retardant finishing liquid is an aqueous solution of the alkylamine boric acid phosphoric acid modified meglumine flame retardant and the catalyst dicyandiamide as described in claim 5.

7. The method for preparing the alkylamine boric acid phosphoric acid modified meglumine flame retardant according to claim 6, characterized in that: In the durable flame retardant finishing liquid, the concentration of the alkylamine boric acid phosphoric acid modified meglumine flame retardant is 10 to 200 g / L; The mass concentration of dicyandiamide is 4-10wt%.

8. Use of the durable flame retardant finishing liquid as claimed in claim 6 or 7 in durable flame retardant finishing of cotton fabrics.

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