Chitosan-based intumescent flame retardant modified polypropylene composite material and preparation method thereof
By introducing chitosan-based expanded flame retardant into polypropylene, using melamine grafted chitosan and isocyanate-based phosphophthalene materials, the problem of poor flame retardancy of polypropylene materials is solved, and significant improvement in flame retardant performance and smoke suppression effect are achieved.
Patent Information
- Application Number
- CN202411788086.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-06
- Publication Date
- 2025-02-25
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Polypropylene materials have poor smoke resistance and flame retardancy, which leads to the release of a large amount of toxic smoke during combustion, affecting its industrial development and market demand.
By preparing chitosan-based expanded flame retardant, the flame retardant properties of the melamine grafted chitosan are formed by using materials such as melamine grafted chitosan and isocyanate grafted chitosan, which is copolymerized with polypropylene as an expanded flame retardant to enhance its flame retardant properties.
It significantly enhances the flame retardant performance of polypropylene, improves its smoke resistance and drip anti-flux effect, forms a good carbon barrier layer, and effectively suppresses combustion.
Smart Images
Figure CN119505422A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of flame retardancy, in particular to a chitosan-based expansion flame retardant modified polypropylene composite material and a preparation method thereof. Background Art
[0002] Polypropylene is a common polymer material, widely used in clothing, fiber products such as blankets, medical equipment, pipelines, food packaging, etc. Traditional polypropylene has poor flame retardancy, is easy to burn, and releases a large amount of toxic smoke, which hinders the industrial development and market demand of polypropylene. Therefore, flame retardant modification of polypropylene has become a research hotspot.
[0003] Phosphorus-containing flame retardants are flame retardants with good flame retardant effects, such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). The literature "Preparation and Thermal Properties of Flame Retardant Modified Epoxy Acrylic Resin Containing DOPO Phosphate" discloses that DOPO, formaldehyde, and toluene diisocyanate are used as reactants to prepare isocyanate-containing phosphaphenanthrene (C 22 H 17 N2O5P), has excellent flame retardant effect on light-cured epoxy acrylate resin. Chitosan, as a natural polymer compound, has a wide source and can be used as a natural expanding carbon source. It has a useful application in the field of flame retardancy. Therefore, chitosan can be combined with nitrogen and phosphorus flame retardants to form an expanding flame retardant, which can be applied to polypropylene to enhance its flame retardant properties. Summary of the invention
[0004] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides a chitosan-based intumescent flame retardant modified polypropylene composite material and a preparation method thereof, which solves the problem of poor smoke suppression and flame retardancy of polypropylene materials.
[0005] (II) Technical solution To achieve the above object, the present invention provides the following technical solution: a chitosan-based intumescent flame retardant modified polypropylene composite material, wherein the preparation method of the chitosan-based intumescent flame retardant modified polypropylene composite material comprises the following steps: (1) Preparation of melamine grafted chitosan: Add 1.5-3% acetic acid solution to a reaction bottle, add chitosan and stir to dissolve, add glutaraldehyde and melamine to carry out coupling reaction, add sodium hydroxide after the reaction to neutralize and precipitate, and then centrifuge and wash with distilled water to obtain melamine grafted chitosan.
[0006] (2) Preparation of chitosan-based intumescent flame retardant: Add the mixed solvent and melamine-grafted chitosan to the reaction bottle and stir to swell, then add isocyanate-based phosphaphenanthrene (C 22 H 17N2O5P) and a catalyst are reacted at 70-100 ℃ for 12-36 h, and after the reaction, they are placed in an ice water bath for cooling, deionized water is added to form a precipitate, and then acetone and ethanol are used for centrifugal washing in sequence to obtain phosphaphenanthrene-melamine grafted chitosan, which is a chitosan-based intumescent flame retardant.
[0007] (3) Preparation of chitosan-based intumescent flame retardant modified polypropylene composite material: polypropylene, chitosan-based intumescent flame retardant, 0.2-0.6% antioxidant 1010, 0.5-1.5% lubricant hard polypropylene wax, and 0.2-1% antistatic agent carbon black are placed in a double-roll mill, and plasticized at 120-135 °C, and then extruded to obtain a masterbatch to obtain a chitosan-based intumescent flame retardant modified polypropylene composite material.
[0008] Preferably, in step (1), the mass ratio of chitosan, glutaraldehyde and melamine is 100:15-30:6-15.
[0009] Preferably, the coupling reaction temperature in step (1) is 30-60°C, and the reaction time is 6-12 h.
[0010] Preferably, the catalyst in step (2) is stannous octoate.
[0011] Preferably, the mixed solvent in step (2) is N,N-dimethylformamide and 1,4-dioxane, and the volume ratio of the two is 100:25-60.
[0012] Preferably, in step (2), the mass ratio of melamine-grafted chitosan, isocyanate-based phosphaphenanthrene and catalyst is 100:18-40:0.06-0.15.
[0013] Preferably, in step (3), the mass ratio of polypropylene to chitosan-based intumescent flame retardant is 100:3-8.
[0014] 3. Beneficial technical effects Compared with the prior art, the present invention has the following beneficial technical effects: The chitosan-based intumescent flame retardant modified polypropylene composite material uses glutaraldehyde as a crosslinking agent to react with the amino groups of chitosan and melamine respectively to produce Schiff base reaction to obtain melamine-grafted chitosan, thereby grafting melamine into chitosan; then, under the catalytic action of stannous octoate, the isocyanate functional group of isocyanate-based phosphaphenanthrene and the amino groups of chitosan-grafted melamine undergo addition reaction to obtain phosphaphenanthrene-melamine-grafted chitosan, thereby further grafting phosphaphenanthrene small molecules into chitosan.
[0015] The invention discloses a chitosan-based intumescent flame retardant modified polypropylene composite material. The chitosan molecules in the phosphaphenanthrene-melamine grafted chitosan have a high carbon content. The chitosan molecules are used as a natural intumescent carbon source, melamine is used as a gas source, and the phosphaphenanthrene small molecules are used as a phosphorus source to form an intumescent flame retardant system. The chitosan has good compatibility with polypropylene, so that the phosphaphenanthrene-melamine grafted chitosan is dispersed in a polyethylene matrix. During the combustion process, the phosphaphenanthrene is pyrolyzed to generate phosphoric acid derivatives, which promote carbonization and capture combustion chain free radicals. Melamine is pyrolyzed to generate nitrogen, ammonia and other gases to form a gas source, which promotes the thermal decomposition of chitosan to form a continuous and dense carbon barrier layer, thereby achieving good smoke suppression and anti-melting dripping effects, and significantly enhancing the flame retardant performance of polypropylene. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is isocyanate phosphaphenanthrene (C 22 H 17 The molecular structure of N2O5P; Figure 2 It is the structural diagram of melamine grafted chitosan; Figure 3 This is the structural diagram of phosphaphenanthrene-melamine grafted chitosan. DETAILED DESCRIPTION
[0017] To achieve the above object, the present invention provides the following embodiments and examples: A method for preparing a chitosan-based intumescent flame retardant modified polypropylene composite material comprises the following steps: (1) Preparation of melamine grafted chitosan: Add 1.5-3% acetic acid solution to a reaction bottle, add chitosan and stir to dissolve, add glutaraldehyde and melamine in a mass ratio of 100:15-30:6-15, and carry out coupling reaction at 30-60 °C for 6-12 h. After the reaction, add sodium hydroxide to neutralize and precipitate, and then centrifuge and wash with distilled water to obtain melamine grafted chitosan.
[0018] (2) Preparation of chitosan-based intumescent flame retardant: N,N-dimethylformamide and 1,4-dioxane in a volume ratio of 100:25-60 were added to the reaction bottle as a mixed solvent, melamine-grafted chitosan was stirred and swollen, and then isocyanate-based phosphaphenanthrene (C 22 H 17 N2O5P) and catalyst stannous octoate, the mass ratio of the three is 100:18-40:0.06-0.15, react at 70-100 ℃ for 12-36 h, cool in an ice water bath after the reaction, add deionized water to form a precipitate, and then use acetone and ethanol for centrifugal washing in turn to obtain phosphaphenanthrene-melamine grafted chitosan, which is a chitosan-based intumescent flame retardant.
[0019] (3) Preparation of chitosan-based intumescent flame retardant modified polypropylene composite material: polypropylene, 3-8% chitosan-based intumescent flame retardant, 0.2-0.6% antioxidant 1010, 0.5-1.5% lubricant hard polypropylene wax, and 0.2-1% antistatic agent carbon black are placed in a double-roll mill, and plasticized at 120-135 °C, and then extruded to obtain a masterbatch to obtain a chitosan-based intumescent flame retardant modified polypropylene composite material.
[0020] Example 1
[0021] (1) Preparation of melamine-grafted chitosan: Add 1.5% acetic acid solution to a reaction bottle, add chitosan and stir to dissolve, add glutaraldehyde and melamine in a mass ratio of 100:15:6, and carry out coupling reaction at 30 °C for 6 h. After the reaction, add sodium hydroxide to neutralize and precipitate, and then centrifuge and wash with distilled water to obtain melamine-grafted chitosan.
[0022] (2) Preparation of chitosan-based intumescent flame retardant: N,N-dimethylformamide and 1,4-dioxane in a volume ratio of 100:25 were added to the reaction bottle as a mixed solvent, melamine-grafted chitosan was stirred to swell, and then isocyanate-based phosphaphenanthrene (C 22 H 17 N2O5P) and catalyst stannous octoate, the mass ratio of the three is 100:18:0.06, the reaction is carried out at 70 ℃ for 12 h, and then placed in an ice water bath for cooling, deionized water is added to form a precipitate, and then centrifugal washing is carried out with acetone and ethanol in sequence to obtain phosphaphenanthrene-melamine grafted chitosan, which is a chitosan-based intumescent flame retardant.
[0023] (3) Preparation of chitosan-based intumescent flame retardant modified polypropylene composite materials: Polypropylene, 3% chitosan-based intumescent flame retardant, 0.2% antioxidant 1010, 0.5% lubricant hard polypropylene wax, and 0.2% antistatic agent carbon black were placed in a double-roll mill, plasticized at 120°C, and then extruded to obtain a masterbatch to obtain a chitosan-based intumescent flame retardant modified polypropylene composite material.
[0024] Example 2
[0025] (1) Preparation of melamine-grafted chitosan: Add 2% acetic acid solution to a reaction bottle, add chitosan and stir to dissolve, add glutaraldehyde and melamine in a mass ratio of 100:18:8, and carry out coupling reaction at 40 °C for 6 h. After the reaction, add sodium hydroxide to neutralize and precipitate, and then centrifuge and wash with distilled water to obtain melamine-grafted chitosan.
[0026] (2) Preparation of chitosan-based intumescent flame retardant: N,N-dimethylformamide and 1,4-dioxane in a volume ratio of 100:30 were added to the reaction bottle as a mixed solvent, melamine-grafted chitosan was stirred and swollen, and then isocyanate-based phosphaphenanthrene (C 22 H 17 N2O5P) and catalyst stannous octoate, the mass ratio of the three is 100:22:0.08, the reaction is carried out at 80 ℃ for 12 h, and then placed in an ice water bath for cooling, deionized water is added to form a precipitate, and then acetone and ethanol are used for centrifugal washing in turn to obtain phosphaphenanthrene-melamine grafted chitosan, which is a chitosan-based intumescent flame retardant.
[0027] (3) Preparation of chitosan-based intumescent flame retardant modified polypropylene composite materials: Polypropylene, 4% chitosan-based intumescent flame retardant, 0.2% antioxidant 1010, 0.8% lubricant hard polypropylene wax, and 0.4% antistatic agent carbon black were placed in a double-roll mill, plasticized at 120°C, and then extruded to obtain a masterbatch to obtain a chitosan-based intumescent flame retardant modified polypropylene composite material.
[0028] Example 3
[0029] (1) Preparation of melamine-grafted chitosan: Add 2% acetic acid solution to a reaction bottle, add chitosan and stir to dissolve, add glutaraldehyde and melamine in a mass ratio of 100:22:10, and carry out coupling reaction at 50 °C for 8 h. After the reaction, add sodium hydroxide to neutralize and precipitate, and then centrifuge and wash with distilled water to obtain melamine-grafted chitosan.
[0030] (2) Preparation of chitosan-based intumescent flame retardant: N,N-dimethylformamide and 1,4-dioxane in a volume ratio of 100:35 were added to the reaction bottle as a mixed solvent, melamine-grafted chitosan was stirred and swollen, and then isocyanate-based phosphaphenanthrene (C 22 H 17 N2O5P) and catalyst stannous octoate, the mass ratio of the three is 100:30:0.1, the reaction is carried out at 80 ℃ for 24 h, and then placed in an ice water bath for cooling, deionized water is added to form a precipitate, and then centrifugal washing is carried out with acetone and ethanol in sequence to obtain phosphaphenanthrene-melamine grafted chitosan, which is a chitosan-based intumescent flame retardant.
[0031] (3) Preparation of chitosan-based intumescent flame retardant modified polypropylene composite materials: Polypropylene, 5% chitosan-based intumescent flame retardant, 0.4% antioxidant 1010, 1% lubricant hard polypropylene wax, and 0.6% antistatic agent carbon black were placed in a double-roll mill, plasticized at 125°C, and then extruded to obtain a masterbatch to obtain a chitosan-based intumescent flame retardant modified polypropylene composite material.
[0032] Example 4
[0033] (1) Preparation of melamine-grafted chitosan: Add 2.5% acetic acid solution to a reaction bottle, add chitosan and stir to dissolve, add glutaraldehyde and melamine in a mass ratio of 100:26:12.5, and carry out coupling reaction at 40 °C for 10 h. After the reaction, add sodium hydroxide to neutralize and precipitate, and then centrifuge and wash with distilled water to obtain melamine-grafted chitosan.
[0034] (2) Preparation of chitosan-based intumescent flame retardant: N,N-dimethylformamide and 1,4-dioxane in a volume ratio of 100:52 were added to the reaction bottle as a mixed solvent, melamine-grafted chitosan was stirred and swollen, and then isocyanate-based phosphaphenanthrene (C 22 H 17 N2O5P) and catalyst stannous octoate, the mass ratio of the three is 100:34:0.13, the reaction is carried out at 100 ℃ for 36 h, and then placed in an ice water bath for cooling, deionized water is added to form a precipitate, and then acetone and ethanol are used for centrifugal washing in turn to obtain phosphaphenanthrene-melamine grafted chitosan, which is a chitosan-based intumescent flame retardant.
[0035] (3) Preparation of chitosan-based intumescent flame retardant modified polypropylene composite materials: Polypropylene, 7% chitosan-based intumescent flame retardant, 0.5% antioxidant 1010, 1.2% lubricant hard polypropylene wax, and 0.8% antistatic agent carbon black were placed in a double-roll mill, plasticized at 135 °C, and then extruded to obtain a masterbatch to obtain a chitosan-based intumescent flame retardant modified polypropylene composite material.
[0036] Example 5
[0037] (1) Preparation of melamine-grafted chitosan: Add 3% acetic acid solution to a reaction bottle, add chitosan and stir to dissolve, add glutaraldehyde and melamine in a mass ratio of 100:30:15, and carry out coupling reaction at 60 °C for 12 h. After the reaction, add sodium hydroxide to neutralize and precipitate, and then centrifuge and wash with distilled water to obtain melamine-grafted chitosan.
[0038] (2) Preparation of chitosan-based intumescent flame retardant: N,N-dimethylformamide and 1,4-dioxane in a volume ratio of 100:60 were added to the reaction bottle as a mixed solvent, melamine-grafted chitosan was stirred and swollen, and then isocyanate-based phosphaphenanthrene (C 22 H 17N2O5P) and catalyst stannous octoate, the mass ratio of the three is 100:40:0.15, the reaction is carried out at 100 ℃ for 36 h, and then placed in an ice water bath for cooling, deionized water is added to form a precipitate, and then acetone and ethanol are used for centrifugal washing in turn to obtain phosphaphenanthrene-melamine grafted chitosan, which is a chitosan-based intumescent flame retardant.
[0039] (3) Preparation of chitosan-based intumescent flame retardant modified polypropylene composite materials: Polypropylene, 8% chitosan-based intumescent flame retardant, 0.6% antioxidant 1010, 1.5% lubricant hard polypropylene wax, and 1% antistatic agent carbon black were placed in a double-roll mill, plasticized at 135 °C, and then extruded to obtain a masterbatch to obtain a chitosan-based intumescent flame retardant modified polypropylene composite material.
[0040] Comparative Example 1 (1) Preparation of melamine-grafted chitosan: Add 2% acetic acid solution to a reaction bottle, add chitosan and stir to dissolve, add glutaraldehyde and melamine in a mass ratio of 100:22:10, and carry out coupling reaction at 40 °C for 6 h. After the reaction, add sodium hydroxide to neutralize and precipitate, and then centrifuge and wash with distilled water to obtain melamine-grafted chitosan.
[0041] (2) Polypropylene, 5% melamine grafted chitosan, 0.4% antioxidant 1010, 1.2% lubricant hard polypropylene wax, and 0.6% antistatic agent carbon black were placed in a double-roll mill, plasticized at 125 °C, and then extruded to obtain a masterbatch to obtain a chitosan-modified polypropylene composite material.
[0042] The chitosan-modified polypropylene composite material was made into a standard specimen of 20 mm×10 mm×10 mm, and then the combustion performance was tested by a cone calorimeter with a heating rate of 10°C / min and a test temperature of 25-700°C.
[0043]
[0044]
Claims
1. A chitosan-based intumescent flame retardant modified polypropylene composite material, characterized in that: The preparation method of the chitosan-based intumescent flame retardant modified polypropylene composite material comprises the following steps: (1) Preparation of melamine grafted chitosan: Add 1.5-3% acetic acid solution to a reaction bottle, add chitosan and stir to dissolve, add glutaraldehyde and melamine to carry out coupling reaction, add sodium hydroxide to neutralize and precipitate after the reaction, and then centrifuge and wash with distilled water to obtain melamine grafted chitosan; (2) Preparation of chitosan-based intumescent flame retardant: Add the mixed solvent and melamine-grafted chitosan to the reaction bottle and stir to swell, then add isocyanate-based phosphaphenanthrene (C 22 H 17 N2O5P) and a catalyst, react at 70-100 °C for 12-36 h, cool in an ice water bath after the reaction, add deionized water to form a precipitate, and then centrifuge and wash with acetone and ethanol in sequence to obtain phosphaphenanthrene-melamine grafted chitosan, which is a chitosan-based intumescent flame retardant; (3) Preparation of chitosan-based intumescent flame retardant modified polypropylene composite material: polypropylene, chitosan-based intumescent flame retardant, 0.2-0.6% antioxidant 1010, 0.5-1.5% lubricant hard polypropylene wax, and 0.2-1% antistatic agent carbon black are placed in a double-roll mill, and plasticized at 120-135 °C, and then extruded to obtain a masterbatch to obtain a chitosan-based intumescent flame retardant modified polypropylene composite material.
2. The chitosan-based intumescent flame retardant modified polypropylene composite material according to claim 1, characterized in that: In the step (1), the mass ratio of chitosan, glutaraldehyde and melamine is 100:15-30:6-15.
3. The chitosan-based intumescent flame retardant modified polypropylene composite material according to claim 1, characterized in that: The coupling reaction temperature in step (1) is 30-60°C and the reaction time is 6-12 h.
4. The chitosan-based intumescent flame retardant modified polypropylene composite material according to claim 1, characterized in that: The catalyst in step (2) is stannous octoate.
5. The chitosan-based intumescent flame retardant modified polypropylene composite material according to claim 1, characterized in that: The mixed solvent in step (2) is N,N-dimethylformamide and 1,4-dioxane, and the volume ratio of the two is 100:25-60.
6. The chitosan-based intumescent flame retardant modified polypropylene composite material according to claim 1, characterized in that: In the step (2), the mass ratio of melamine grafted chitosan, isocyanate phosphaphenanthrene and catalyst is 100:18-40:0.06-0.
15.
7. The chitosan-based intumescent flame retardant modified polypropylene composite material according to claim 1, characterized in that: In the step (3), the mass ratio of polypropylene to chitosan-based intumescent flame retardant is 100:3-8.