Biomass flame retardant and preparation method thereof

Abstract

The invention discloses a biomass flame retardant and a preparation method thereof, and the flame retardant is prepared by carrying out physical crosslinking on a phosphorus-containing material, a nitrogen-containing material and a char-forming material to form a three-dimensional network structure and carrying out hydrophobic modification. The preparation method comprises the following steps: dissolving a nitrogen-containing material and a char-forming material, and mixing with a phosphorus-containing material to form hydrogel; performing freeze drying to obtain dry gel; and treating with a hydrophobic modifier and drying. The prepared flame retardant does not contain halogen and heavy metal and is environmentally friendly, and through a three-dimensional porous structure and hydrophobic modification, the flame retardance, the heat insulation property and the water resistance are effectively improved.

Description

Technical Field

[0001] This application relates to a biomass flame retardant and its preparation method, belonging to the field of flame retardant technology. Background Technology

[0002] As society places increasing emphasis on safety in production and daily life, the demand for flame-retardant properties in various materials is growing. For example, home textiles, outdoor advertising materials, and decorative fabrics for public places all have specific requirements for the flame-retardant properties of materials.

[0003] Currently, the flame retardants widely used in the market are still mainly based on the bromine-antimony system. This type of flame retardant has advantages such as high flame retardant efficiency and low dosage. However, during combustion, bromine-antimony flame retardants release large amounts of toxic gases that are asphyxiating and corrosive, posing a potential threat to human health and causing persistent environmental pollution. Furthermore, the bromine compounds contained in this type of flame retardant have certain bioaccumulation and ecotoxicity, are difficult to degrade under natural conditions, and pose long-term environmental risks. Therefore, developing efficient, low-toxicity, and environmentally friendly flame retardant systems has become a critical issue that urgently needs to be addressed in this field. Summary of the Invention

[0004] The purpose of this application is to overcome the shortcomings of the prior art and provide a biomass flame retardant and its preparation method, thereby solving the technical problems that the flame retardant components of existing flame retardants are complex and do not meet environmental protection standards.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: In a first aspect, this application provides a biomass flame retardant, which is prepared by physically cross-linking phosphorus-containing materials, nitrogen-containing materials and char-forming materials to form a three-dimensional network structure, and then by hydrophobic modification.

[0006] In conjunction with the first aspect, the phosphorus-containing material is further selected from at least one of ammonium polyphosphate (II), sodium polyphosphate, and potassium polyphosphate.

[0007] Furthermore, the nitrogen-containing material is selected from at least one of urea, chitosan oligosaccharide, and polyethyleneimine.

[0008] Furthermore, the char-forming material is selected from at least one of glucose, glucosinolate, and carboxymethyl cellulose.

[0009] Furthermore, the hydrophobic modifier used for hydrophobic modification is selected from at least one of methyltrimethoxysilane, ethyltrimethoxysilane, and vinyltriethoxysilane.

[0010] Secondly, this application provides a method for preparing a biomass flame retardant, comprising: Nitrogen-containing materials and carbon-forming materials are dissolved in deionized water, then mixed with phosphorus-containing materials, and stirred to form a physically cross-linked hydrogel. The hydrogel was freeze-dried to obtain a dry gel; The dry gel was hydrophobically modified using a hydrophobic modifier, and then the hydrophobically modified product was dried to obtain a biomass flame retardant.

[0011] In conjunction with the second aspect, further, the raw materials are in the following proportions by mass: 8-12 parts nitrogen-containing materials, 8-12 parts char-forming materials, 15-20 parts deionized water, and 15-20 parts phosphorus-containing materials; the stirring reaction time is 5-10 minutes.

[0012] Furthermore, the hydrophobic modification treatment includes: dissolving the hydrophobic modifier in anhydrous ethanol to prepare a solution with a concentration of 1-5 wt%, adjusting the pH of the solution to 3-5 with acetic acid, hydrolyzing and activating for 1-3 hours, and then adding dry gel for soaking for 1-3 hours.

[0013] Furthermore, the freeze-drying process includes: pre-freezing the hydrogel at -40°C to -60°C for 2-4 hours, and then drying it in a freeze dryer at -50°C to -80°C and a vacuum of less than 10 Pa for 12-24 hours.

[0014] Furthermore, the drying conditions are: drying at 60°C to 80°C for 2-4 hours.

[0015] Compared with the prior art, the beneficial effects achieved by this application are as follows: This application provides a biomass flame retardant and its preparation method, which forms a three-dimensional hydrogel network by physically cross-linking phosphorus-containing, nitrogen-containing and char-forming materials in solution; The hydrogel was dehydrated and shaped using freeze-drying technology, which fully preserved the three-dimensional porous framework structure. This not only increased the specific surface area of ​​the material, but also enhanced the carbonization barrier and heat insulation effect of the final product due to its porous characteristics. By using a hydrophobic modifier to modify the surface of a porous dry gel with high reactivity, the technical problems of biomass flame retardants being prone to moisture absorption and water intolerant are solved. Detailed Implementation

[0016] The present application will be further described below. The following embodiments are only used to illustrate the technical solution of the present application more clearly, and should not be used to limit the scope of protection of the present application.

[0017] Example 1:

[0018] This embodiment provides a method for preparing a biomass flame retardant coating, specifically including the following steps: Preparation of hydrogel: First, dissolve 8 parts of urea and 8 parts of glucose in 20 parts of deionized water, then add 15 parts of ammonium polyphosphate (II), and stir for 5 minutes to form a hydrogel; Preparation of dry gel: The hydrogel was pre-frozen at -40℃ to -60℃ for 4 hours, and then dried in a freeze dryer at -50℃ to -80℃ and a vacuum degree of less than 10 Pa for 24 hours to prepare a block dry gel.

[0019] Hydrophobic modification: Methyltrimethoxysilane hydrophobic agent was dissolved in anhydrous ethanol to prepare a 5 wt% solution. The pH of the solution was adjusted to 3-5 with acetic acid. After hydrolysis and activation for 3 hours, dry gel was added and soaked for 3 hours, followed by drying at 80°C for 4 hours.

[0020] Flame-retardant coating: The above-mentioned hydrophobic modified dry gel was ground into micro-powder and dispersed in deionized water to prepare a dispersion with a solid content of 60%. The dispersion was then coated onto a polyester mesh fabric, once on each of the front and back sides. The polyester mesh fabric used in this embodiment was 500D 30*30. The coated sample was then placed in an oven at 100℃ and dried for 10 minutes to form a dry gel coating. The thickness of the dried sample was 0.34 mm. The oxygen index of the coated sample was measured to be 28%~29%.

[0021] Example 2:

[0022] This embodiment provides a method for preparing a biomass flame retardant coating, specifically including the following steps: Preparation of hydrogel: First, dissolve 12 parts of urea and 12 parts of glucose in 20 parts of deionized water, then add 20 parts of ammonium polyphosphate (II), and stir for 5 minutes to form a hydrogel; Preparation of dry gel: The hydrogel was pre-frozen at -40℃ to -60℃ for 4 hours, and then dried in a freeze dryer at -50℃ to -80℃ and a vacuum degree of less than 10 Pa for 24 hours to prepare a block dry gel.

[0023] Hydrophobic modification: Methyltrimethoxysilane hydrophobic agent was dissolved in anhydrous ethanol to prepare a 5 wt% solution. The pH of the solution was adjusted to 3-5 with acetic acid. After hydrolysis and activation for 3 hours, dry gel was added and soaked for 3 hours, followed by drying at 80°C for 4 hours.

[0024] Flame-retardant coating: The above-mentioned hydrophobic modified dry gel was ground into micro-powder and dispersed in deionized water to prepare a dispersion with a solid content of 60%. The dispersion was then coated onto a polyester mesh fabric, once on each of the front and back sides. The polyester mesh fabric used in this embodiment was 500D 30*30. The coated sample was then placed in an oven at 100℃ and dried for 10 minutes to form a dry gel coating. The thickness of the dried sample was 0.34 mm. The oxygen index of the coated sample was measured to be 34%~35%.

[0025] Example 3:

[0026] This embodiment provides a method for preparing a biomass flame retardant coating, specifically including the following steps: Preparation of hydrogel: First, dissolve 10 parts of urea and 10 parts of glucose in 20 parts of deionized water, then add 18 parts of ammonium polyphosphate (II), and stir for 5 minutes to form a hydrogel; Preparation of dry gel: The hydrogel was pre-frozen at -40℃ to -60℃ for 4 hours, and then dried in a freeze dryer at -50℃ to -80℃ and a vacuum degree of less than 10 Pa for 24 hours to prepare a block dry gel.

[0027] Hydrophobic modification: Methyltrimethoxysilane hydrophobic agent was dissolved in anhydrous ethanol to prepare a 5 wt% solution. The pH of the solution was adjusted to 3-5 with acetic acid. After hydrolysis and activation for 3 hours, dry gel was added and soaked for 3 hours, followed by drying at 80°C for 4 hours.

[0028] Flame-retardant coating: The above-mentioned hydrophobic modified dry gel was ground into micro powder and dispersed in deionized water to prepare a dispersion with a solid content of 60%. The dispersion was then coated onto a polyester mesh fabric, once on each of the front and back sides. The polyester mesh fabric used in this embodiment was 500D 30*30. The coated sample was then placed in an oven at 100℃ and dried for 10 minutes to form a dry gel coating. The thickness of the dried sample was 0.32 mm. The oxygen index of the coated sample was measured to be 34%~35%.

[0029] Comparative Example 1: This comparative example provides a method for preparing a bromine-antimony flame retardant coating, specifically including the following steps: A mixture of bromine and antimony compounds (solid content 63±0.5%, Nantong Newman New Materials) was coated onto a polyester mesh fabric, once on each side. The polyester mesh fabric was 500D 30*30 mm in size. The coating was then dried in an oven at 100℃ for 10 minutes to form a dry gel coating. The thickness of the coated sample was 0.31 mm. The oxygen index of the coated sample was measured to be 33%~34%.

[0030] By comparing the above embodiments and comparative examples, it can be seen that the biomass-based flame retardant prepared in this application exhibits excellent flame retardant performance. Its oxygen index is not only comparable to the currently widely used commercial bromine-antimony synergistic flame retardant system, but even higher under some formulation conditions, fully demonstrating its superior flame retardant efficiency. More importantly, this biomass flame retardant uses renewable natural resources as its main raw material and does not contain toxic and harmful components such as halogens and heavy metals, significantly reducing potential risks to the environment and human health throughout the material's entire life cycle.

[0031] Compared to traditional bromine-antimony flame retardants, which may release persistent organic pollutants such as dioxins and polybrominated diphenyl ethers during combustion, the biomass-based flame retardant provided in this application exhibits good environmental friendliness and sustainable development potential, which is in line with the current development trend of green chemistry and low-carbon materials and has broad prospects for industrial application.

[0032] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A biomass fire retardant, characterized in that, The biomass flame retardant is prepared by physical cross-linking of a phosphorus-containing material, a nitrogen-containing material and a char-forming material to form a three-dimensional network structure, and hydrophobic modification.

2. The biomass fire retardant of claim 1, wherein, The phosphorus-containing material is at least one of ammonium polyphosphate (II), sodium polyphosphate and potassium polyphosphate.

3. The biomass fire retardant of claim 1, wherein, The nitrogen-containing material is at least one of urea, chitooligosaccharide and polyethyleneimine.

4. The biomass fire retardant of claim 1, wherein, The char-forming material is at least one of glucose, glucoside and carboxymethyl cellulose.

5. The biomass fire retardant of claim 1, wherein, The hydrophobic modifier for hydrophobic modification is at least one of methyltrimethoxysilane, ethyltrimethoxysilane and vinyltriethoxysilane.

6. The method of claim 1-5, wherein the biomass flame retardant is prepared by the steps of: The method comprises: dissolving the nitrogen-containing material and the char-forming material in deionized water, then mixing with the phosphorus-containing material, stirring and reacting to form a physically cross-linked hydrogel; freeze-drying the hydrogel to obtain a dry gel; hydrophobically modifying the dry gel using a hydrophobic modifier, then drying the hydrophobically modified product to obtain the biomass flame retardant.

7. The production method according to claim 6, wherein The raw materials are as follows in terms of mass fraction: 8-12 parts of the nitrogen-containing material, 8-12 parts of the char-forming material, 15-20 parts of deionized water and 15-20 parts of the phosphorus-containing material; the stirring and reacting time is 5-10 minutes.

8. The production method according to claim 6, characterized by, The hydrophobic modification process comprises: dissolving the hydrophobic modifier in anhydrous ethanol to prepare a solution with a concentration of 1-5 wt%, adjusting the pH of the solution to 3-5 with acetic acid, and then adding the dry gel for soaking for 1-3 hours after hydrolytic activation for 1-3 hours.

9. The production method according to claim 6, characterized by, The freeze-drying process comprises: pre-freezing the hydrogel at -40℃ to -60℃ for 2-4 hours, and then drying in a freeze dryer at -50℃ to -80℃ and a vacuum degree lower than 10 Pa for 12-24 hours.

10. The method of claim 6, wherein, The drying conditions are as follows: drying at 60℃ to 80℃ for 2-4 hours.