Preparation method of high-expansion phosphoramidated natural polysaccharide flame retardant

Abstract

The invention provides a preparation method of a high-expansion phosphoramidated natural polysaccharide flame retardant. The preparation method comprises the following preparation steps: S1, carrying out amination treatment on a phosphoramidated reagent to obtain a precursor solution; and S2, adding the natural polysaccharide into the precursor solution, and carrying out phosphoramidation reaction to obtain the high-expansion phosphoramidated natural polysaccharide flame retardant. According to the invention, the natural biomass is used as the raw material, and the water is used as the solvent, so that the prepared flame retardant has the advantages of high expansion rate, low environmental hazard, high matrix compatibility and excellent flame retardance. Moreover, on one hand, the flame retardant prepared by the invention has higher expansion rate and fire endurance, and on the other hand, the heat released by the flame retardant during combustion can be reduced and inhibited, so that the harm to the environment is reduced, and the practical effect of the flame retardant prepared by the invention during use is further ensured.

Description

Technical Field

[0001] The invention relates to the technical field of flame retardants, and in particular to a method for preparing a high-expansion aminophosphorylation natural polysaccharide flame retardant. Background Art

[0002] In today's society, fire has always been one of the top issues of public safety, which seriously damages people's life safety and property safety. Therefore, flame retardants are essential to protect against the effects of fire.

[0003] At present, the use of intumescent flame retardants is an effective and economical method, which is usually composed of multiple components to meet the protection requirements. However, the existing intumescent flame retardants still have defects in fire resistance, carbon layer strength and toxic smoke release. Although traditional inorganic flame retardants and halogen flame retardants have good flame retardant properties and a wide range of applications, they have the disadvantages of releasing a lot of smoke and toxic gases when burning, polluting the environment, and most flame retardants do not have excellent carbon expansion performance, which also leads to a poor thermal insulation effect. Therefore, the existing technology has limitations. Summary of the invention

[0004] The present invention is made to solve the above problems, and aims to provide a method for preparing a high-expansion aminophosphorylation natural polysaccharide flame retardant.

[0005] The present invention provides a method for preparing a high-expansion aminophosphorylation natural polysaccharide flame retardant, which has the following characteristics and comprises the following steps:

[0006] S1: performing amination treatment on the phosphating agent to obtain a precursor solution;

[0007] S11: uniformly mixing the phosphating agent and the aminating agent in water at a mass ratio of 1:2 to 2:1, then raising the temperature to 40 to 60° C., and stirring the reaction for 0.5 to 1 hour to obtain a precursor solution;

[0008] S2: adding natural polysaccharide to the precursor solution to carry out aminophosphorylation reaction to obtain high expansion type aminophosphorylation natural polysaccharide flame retardant;

[0009] S21: adding the natural polysaccharide to the precursor solution in a ratio of 4:1 to 2:1 of the mass of the phosphating agent and stirring evenly, then raising the temperature to 90 to 120° C., stirring and reacting for 0.5 to 2 hours, to obtain a crude product;

[0010] S22: The crude product is washed with an organic solvent for multiple times to remove unreacted raw materials and other impurities, and then vacuum dried at 40-60° C. to obtain a high-expansion aminophosphorylation natural polysaccharide flame retardant.

[0011] In the preparation method of the high expansion type aminophosphorylation natural polysaccharide flame retardant provided by the present invention, it can also have the following characteristics: the chemical reaction formula when performing step S1 is as follows:

[0012]

[0013] In the preparation method of the high expansion type aminophosphorylation natural polysaccharide flame retardant provided by the present invention, it can also have the following characteristics: the chemical reaction formula when performing step S2 is as follows:

[0014]

[0015] In the preparation method of the high-expansion aminophosphorylation natural polysaccharide flame retardant provided by the present invention, it can also have the following characteristics: the phosphating agent is one or more of concentrated phosphoric acid, phytic acid, sodium pyrophosphate, sodium polyphosphate, phosphorus pentoxide, and phosphorus oxychloride.

[0016] In the preparation method of the high-expansion aminophosphorylation natural polysaccharide flame retardant provided by the present invention, it can also have the following characteristics: the amination agent is one or more of urea, guanidine, biuret, ethylenediamine, and melamine.

[0017] In the preparation method of the high expansion type aminophosphorylation natural polysaccharide flame retardant provided by the present invention, it can also have the following characteristics: the natural polysaccharide is one or more of chitosan, cyclodextrin (α-, β- or γ-type), lignin and alginate.

[0018] In the preparation method of the high-expansion aminophosphorylation natural polysaccharide flame retardant provided by the present invention, the method can also have the following characteristics: the organic solvent is one or more of methanol, ethanol, n-butanol and isopropanol.

[0019] Functions and Effects of the Invention

[0020] According to the preparation method of a high expansion type aminophosphorylation natural polysaccharide flame retardant involved in the present invention, because natural biomass is used as raw material and water is used as solvent, the prepared flame retardant has the advantages of high expansion rate, low environmental hazard, high matrix compatibility, and excellent flame retardancy. In addition, the flame retardant prepared by the present invention has a high expansion rate and fire resistance limit on the one hand, and can reduce and inhibit the heat released by the flame retardant during combustion, thereby reducing the harm to the environment, thereby ensuring the practical effect of the flame retardant prepared by the present invention when used. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the fire resistance limit when conducting a control test in the present invention;

[0022] Figure 2 This is the infrared spectrum of the high expansion type aminophosphorylation natural polysaccharide flame retardant prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0023] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is specifically described in the following embodiments in conjunction with the accompanying drawings.

[0024] Example 1

[0025] This embodiment 1 provides a method for preparing a high-expansion aminophosphorylation natural polysaccharide flame retardant, comprising the following preparation steps:

[0026] S1: performing amination treatment on the phosphating agent to obtain a precursor solution;

[0027] S11: uniformly mixing the phosphating agent and the aminating agent in water at a mass ratio of 1:2 to 2:1, then raising the temperature to 40 to 60° C., and stirring the reaction for 0.5 to 1 hour to obtain a precursor solution;

[0028] S2: adding natural polysaccharide to the precursor solution to carry out aminophosphorylation reaction to obtain high expansion type aminophosphorylation natural polysaccharide flame retardant;

[0029] S21: adding the natural polysaccharide to the precursor solution in a ratio of 4:1 to 2:1 of the mass of the phosphating agent and stirring evenly, then raising the temperature to 90 to 120° C., stirring and reacting for 0.5 to 2 hours, to obtain a crude product;

[0030] S22: The crude product is washed with an organic solvent for multiple times to remove unreacted raw materials and other impurities, and then vacuum dried at 40-60° C. to obtain a high-expansion aminophosphorylation natural polysaccharide flame retardant.

[0031] In this embodiment 1, the chemical reaction formula when performing step S1 is as follows:

[0032]

[0033] In this embodiment 1, the chemical reaction formula when performing step S2 is as follows:

[0034]

[0035] In this embodiment 1, the phosphating agent is one or more of concentrated phosphoric acid, phytic acid, sodium pyrophosphate, sodium polyphosphate, phosphorus pentoxide, and phosphorus oxychloride.

[0036] In this embodiment 1, the amination agent is one or more of urea, guanidine, biuret, ethylenediamine, melamine

[0037] In this embodiment 1, the natural polysaccharide is one or more of chitosan, cyclodextrin (α-, β- or γ-type), lignin, and alginic acid.

[0038] In this embodiment 1, the organic solvent is one or more of methanol, ethanol, n-butanol, and isopropanol.

[0039] In this Example 1, the specific preparation process of the high expansion type aminophosphorylation natural polysaccharide flame retardant of the present invention is as follows:

[0040] First, phosphoric acid and urea were uniformly mixed in water at a mass ratio of 1:1, and then heated to 50° C. and stirred for reaction for 1 hour to obtain a precursor solution.

[0041] Next, starch was added to the precursor solution at a ratio of 4:1 to phosphoric acid mass, and after stirring evenly, the temperature was raised to 90° C. and stirred for reaction for 1.5 hours to obtain a crude product.

[0042] Finally, the crude product was washed with anhydrous ethanol for several times to remove unreacted raw materials and other impurities, and then vacuum dried at 60° C. to obtain a high-expansion aminophosphorylation natural polysaccharide flame retardant.

[0043] In this embodiment 1, if a high-expansion aminophosphoric acid esterified natural polysaccharide flame retardant is used to prepare a fire-retardant coating, the specific process is as follows: by weight, 60% of an aqueous acrylic emulsion, 10% of a mixture of phenol and catechol, and 30% of a high-expansion aminophosphoric acid esterified natural polysaccharide flame retardant are taken, and mixed evenly to obtain a crude coating, which is further subjected to ultrasonic and high-speed homogenization treatment to obtain a stably dispersed fire-retardant coating.

[0044] Example 2

[0045] The difference between Example 2 and Example 1 is that, based on the preparation method of the high-expansion aminophosphoric acid esterified natural polysaccharide flame retardant of the present invention, another specific preparation process of the high-expansion aminophosphoric acid esterified natural polysaccharide flame retardant is provided, as shown below:

[0046] First, phosphoric acid and urea were uniformly mixed in water at a mass ratio of 2:1, and then heated to 60° C. and stirred for reaction for 1 hour to obtain a precursor solution.

[0047] Next, the natural polysaccharide β-cyclodextrin was added to the precursor solution at a ratio of 2:1 to the mass of phosphoric acid, and after stirring evenly, the temperature was raised to 110° C. and stirred for reaction for 2 hours to obtain a crude product.

[0048] Finally, the crude product was washed with anhydrous ethanol for several times to remove unreacted raw materials and other impurities, and then vacuum dried at 60° C. to obtain a high-expansion aminophosphorylation natural polysaccharide flame retardant.

[0049] In this embodiment 2, if a high-expansion aminophosphoric acid esterified natural polysaccharide flame retardant is used to prepare a fire-retardant coating, the specific process is as follows: by weight, 60% of an aqueous acrylic emulsion, 10% of an alkaline lignin, and 30% of a high-expansion aminophosphoric acid esterified natural polysaccharide flame retardant are taken, and mixed evenly to obtain a crude coating, which is further subjected to ultrasonic and high-speed homogenization treatment to obtain a stably dispersed fire-retardant coating.

[0050] Apart from this, the other contents of Example 2 are the same as those of Example 1.

[0051] Control group

[0052] A fire retardant coating prepared by a ternary expansion system based on ammonium polyphosphate (APP), melamine (MEL) and pentaerythritol (PER) commonly used in the prior art is compared, wherein the preparation method of the fire retardant coating specifically comprises the following steps:

[0053] Step 1: Take 5 to 20 parts of ammonium polyphosphate, 5 to 20 parts of melamine, and 5 to 10 parts of pentaerythritol and grind them in a ball mill for 6 hours to obtain an intumescent flame retardant;

[0054] Step 2: by weight, 60% of waterborne acrylic emulsion, 10% of carbon forming agent, and 30% of intumescent flame retardant are mixed evenly to obtain a crude coating, and further subjected to ultrasonic and high-speed homogenization treatment to obtain a stably dispersed fire-retardant coating.

[0055] Comparative experiment

[0056] The flame retardant and fire resistant properties of the fire retardant coatings prepared in Example 1 and Example 2 were obtained through comparative experiments. The fire resistant properties were tested according to the "General Code for Fire Protection of Buildings" (GB 55037-2022), and the fire resistant properties test furnace was used for the experiment.

[0057] Specifically, the flame retardant coatings obtained in Example 1 and Example 2 were compared with the flame retardant coatings obtained in the control group to obtain the flame retardant and fire resistant properties of the fire retardant coatings prepared by the preparation method of the high expansion type aminophosphorylation natural polysaccharide flame retardant of the present invention. 2 ), expansion rate, and fire resistance limit to reflect the flame retardant and fire resistance performance. The specific results are shown in the following table.

[0058] Table 1

[0059]

[0060]

[0061] In summary, the comparison between the control group and Examples 1 and 2 shows that the fire retardant coating prepared by the commonly used ternary intumescent flame retardant is compared with the fire retardant coating prepared by the high-expansion aminophosphoric acid esterified natural polysaccharide flame retardant in Examples 1 and 2 of the present invention. It can be obtained that the peak heat release rate (pHRR) of the fire retardant coating prepared in Examples 1 and 2 is 65.6% and 80.3% lower than that of the control group. And its coating expansion rate is increased by nearly 8 times and 11 times, and the fire resistance limit is significantly improved. Thus, it is shown that the high-expansion aminophosphoric acid esterified natural polysaccharide flame retardant in the present invention can significantly increase the fire retardant properties of the fire retardant coating.

[0062] Functions and Effects of the Embodiments

[0063] According to the preparation method of a high expansion type aminophosphorylation natural polysaccharide flame retardant involved in the present invention, because natural biomass is used as raw material and water is used as solvent, the prepared flame retardant has the advantages of high expansion rate, low environmental hazard, high matrix compatibility, and excellent flame retardancy. In addition, the flame retardant prepared by the present invention has a high expansion rate and fire resistance limit on the one hand, and can reduce and inhibit the heat released by the flame retardant during combustion, thereby reducing the harm to the environment, thereby ensuring the practical effect of the flame retardant prepared by the present invention when used.

[0064] The above-mentioned embodiments are preferred examples of the present invention and are not intended to limit the protection scope of the present invention.

Claims

1. A method for preparing a high-expansion aminophosphorylation natural polysaccharide flame retardant, characterized in that: The following steps are involved: S1: performing amination treatment on the phosphating agent to obtain a precursor solution; S11: uniformly mixing the phosphating agent and the aminating agent in water at a mass ratio of 1:2 to 2:1, then raising the temperature to 40 to 60° C., and stirring the mixture for 0.5 to 1 h to obtain the precursor solution; S2: adding the natural polysaccharide to the precursor solution to carry out an aminophosphorylation reaction to obtain the high expansion type aminophosphorylation natural polysaccharide flame retardant; S21: adding the natural polysaccharide to the precursor solution in a ratio of 4:1 to 2:1 of the mass of the phosphating agent and stirring evenly, then raising the temperature to 90 to 120° C., stirring and reacting for 0.5 to 2 hours, to obtain a crude product; S22: The crude product is washed with an organic solvent for multiple times to remove unreacted raw materials and other impurities, and then vacuum dried at 40-60° C. to obtain the high-expansion aminophosphorylation natural polysaccharide flame retardant.

2. The method for preparing the high expansion type aminophosphorylation natural polysaccharide flame retardant according to claim 1, characterized in that: The chemical reaction formula when performing step S1 is as follows:

3. The method for preparing the high expansion type aminophosphorylation natural polysaccharide flame retardant according to claim 1, characterized in that: The chemical reaction formula when performing step S2 is as follows:

4. The method for preparing the high expansion type aminophosphorylation natural polysaccharide flame retardant according to claim 1, characterized in that: in, The phosphating agent is one or more of concentrated phosphoric acid, phytic acid, sodium pyrophosphate, sodium polyphosphate, phosphorus pentoxide, and phosphorus oxychloride.

5. The method for preparing the high expansion type aminophosphorylation natural polysaccharide flame retardant according to claim 1, characterized in that: in, The amination agent is one or more of urea, guanidine, biuret, ethylenediamine and melamine.

6. The method for preparing the high expansion type aminophosphorylation natural polysaccharide flame retardant according to claim 1, characterized in that: in, The natural polysaccharide is one or more of chitosan, cyclodextrin (α-, β- or γ-type), lignin and alginic acid.

7. The method for preparing the high expansion type aminophosphorylation natural polysaccharide flame retardant according to claim 1, characterized in that: in, The organic solvent is one or more of methanol, ethanol, n-butanol and isopropanol.

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