A nano-silicon dioxide synergistic flame-retardant polypropylene composite material and preparation method thereof

Abstract

The present invention relates to the technical field of polymer materials, and specifically discloses a nano-silicon dioxide synergistic flame-retardant polypropylene composite material and a preparation method thereof, which comprises, by weight, 50-70 parts of PP resin, 10-20 parts of flame retardant, 2-8 parts of flame retardant synergist, 1-5 parts of flow modifier, 0.2-0.8 parts of anti-drip agent, and 0.5-2 parts of antioxidant. Compared with the prior art, the present invention has the beneficial effect that the flame-retardant polypropylene composite material prepared by the present invention has excellent performance in tensile strength, elongation at break, flexural strength, impact strength, melt index, and limiting oxygen index.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a nano-silicon dioxide synergistic flame-retardant polypropylene composite material and a preparation method thereof. Background Art

[0002] With the continuous upgrading of products in the automotive, electronic and electrical manufacturing industries, polypropylene (PP) modified composite materials have become a hot topic in current material research due to their lightweight and high performance. Polypropylene materials are widely used in many fields of life and production due to their low density, good thermal stability, low cost, easy processing and many other advantages. However, the limiting oxygen index of polypropylene materials is about 18%, which is easy to burn and produces a large amount of toxic smoke during combustion, limiting the application scope of PP.

[0003] Adding flame retardants is an effective way to improve the flame retardant properties of PP. Commonly used flame retardants are divided into halogen flame retardants and halogen-free flame retardants. Due to environmental protection issues, the industry currently directly uses halogen-free flame retardants to modify PP. The decomposition temperature of halogen-free flame retardant materials is low. If the temperature rises during the processing, the flame retardant will decompose and the flame retardant performance will decrease. In addition, the addition of a large amount of flame retardants will seriously affect the mechanical properties of the material. Summary of the invention

[0004] In order to solve the problems mentioned in the above background technology, the present invention provides a nano-silicon dioxide synergistic flame-retardant polypropylene composite material and a preparation method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention provides a nano-silicon dioxide synergistic flame-retardant polypropylene composite material, which comprises, by weight, 50-70 parts of PP resin, 10-20 parts of flame retardant, 2-8 parts of flame retardant synergist, 1-5 parts of flow modifier, 0.2-0.8 parts of anti-drip agent, and 0.5-2 parts of antioxidant;

[0007] The preparation method of the flame retardant is as follows:

[0008] The phosphoamidation reaction of diphenylphosphinyl chloride and piperazine was carried out to obtain a phosphoamide derivative;

[0009] The flame retardant is obtained by subjecting the phosphonamide derivative to a ring-opening reaction with glycidyl methacrylate;

[0010] The preparation method of the flame retardant synergist is as follows:

[0011] Dispersing nano-silica in an ethanol-water solution, adding silane coupling agent KH-570, and heating for reaction to obtain modified nano-silica;

[0012] The dendritic lubricant is dispersed in tetrahydrofuran, and modified nano-silicon dioxide is added, ultrasonically dispersed, and dried to obtain the flame retardant synergist.

[0013] Preferably, the molar ratio of diphenylphosphine chloride to piperazine is 1:(0.9-1.1).

[0014] Preferably, the molar ratio of the phosphamide derivative to glycidyl methacrylate is 1:(0.9-1.1).

[0015] Preferably, the mass ratio of the nano-silicon dioxide to KH-570 is 1:(0.1-0.2).

[0016] Preferably, the mass ratio of the dendritic lubricant and the modified nano-silicon dioxide is (1-2):1.

[0017] Preferably, the flow modifier is Elevast polymer modifier; the anti-drip agent is fluorine-containing polymer anti-drip agent; and the antioxidant is antioxidant 1010 and / or antioxidant 168.

[0018] A second aspect of the present invention provides a method for preparing a polypropylene composite material, comprising the following steps:

[0019] The PP resin, flame retardant, flame retardant synergist, anti-dripping agent and antioxidant are premixed, and a flow modifier is added for secondary premixing. The secondary premixed materials are sent to a twin-screw extruder for extrusion granulation to obtain the polypropylene composite material.

[0020] Preferably, the parameters of the twin-screw extruder are: temperature settings: zone 1 110±10℃, zone 2 150±10℃, zone 3 165±10℃, zone 4 165±10℃, zone 5 165±10℃, zone 6 160±10℃, zone 7 160±10℃, zone 8 160±10℃, zone 9 165±10℃, die head 165±10℃; main engine speed: 30±3Hz; main engine current: 150±10A; feeding speed: 10±2Hz; vacuum: -0.07±0.03MPa.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The flame-retardant polypropylene composite material prepared by the present invention has excellent performance in tensile strength, elongation at break, flexural strength, impact strength, melt index and limiting oxygen index.

[0023] 2. When the flame retardant of the present invention and the flame retardant synergist are used in combination, the flame retardant performance is significantly improved, and a synergistic enhancement effect is achieved.

[0024] 3. The flame retardant of the present invention is obtained by phosphoramidation of diphenylphosphinoyl chloride and piperazine, and then undergoing a ring-opening reaction with glycidyl methacrylate. The flame retardant synergist is obtained by modifying nano-silica with KH-570 and then dispersing it in a dendritic lubricant. The double bonds contained in the molecules of the flame retardant and the flame retardant synergist can undergo a graft polymerization reaction with the PP resin during the twin-screw extrusion granulation process, which is convenient for the dispersion of the flame retardant and the flame retardant synergist, forming a strong interface bond, and by adjusting the appropriate ratio of phosphorus, nitrogen and carbon, a good flame retardant effect can be synergistically exerted. DETAILED DESCRIPTION

[0025] Unless otherwise specified, the raw materials and reagents used in the present invention are commercially available or can be prepared by known methods.

[0026] Among them, PP resin: Formosa Plastics Industry (Ningbo) Co., Ltd., 3080;

[0027] Nano-silicon dioxide: Shanghai Huijingya Nano New Materials Co., Ltd., particle size 5-20nm;

[0028] Anti-dripping agent: Guangzhou Energy Innovation Materials Co., Ltd., SN3308;

[0029] Antioxidant: BASF, 1010, 168;

[0030] Dendritic lubricant: Weihai Chenyuan Molecular New Materials Co., Ltd., CYD-P214;

[0031] Flow improver: ExxonMobil, Elevast A80;

[0032] Preparation Example 1

[0033] Preparation of flame retardant:

[0034] Disperse piperazine (43 g, 0.5 mol) and 140 ml of triethylamine in 500 ml of chloroform, add diphenylphosphine chloride (118.3 g, 0.5 mol) dropwise at 0°C with stirring, and after the addition is complete, heat to 25°C and stir to react for 5 h, filter, wash with water, and dry to obtain a phosphamide derivative;

[0035] The phosphonamide derivative (85.65 g, 0.3 mol) was dispersed in 500 ml of acetone, glycidyl methacrylate (42.64 g, 0.3 mol) was added, and the mixture was heated under reflux for 8 hours, and the solvent was removed to obtain the flame retardant.

[0036] Preparation Example 2

[0037] Preparation of flame retardant synergist:

[0038] Disperse 15g of silane coupling agent KH-570 (γ-methacryloxypropyltrimethoxysilane) in a mixed solution of 80mL of anhydrous ethanol and deionized water (ethanol: water mass ratio = 9:1) for later use, disperse 80g of nano-silicon dioxide in 250mL of anhydrous ethanol, ultrasonically disperse for 40min, stir and heat to 80°C, dropwise add the mixed solution of the silane coupling agent, continue to react for 2h after the dropwise addition is completed, remove the solvent, and obtain modified nano-silicon dioxide;

[0039] 50 g of the dendritic lubricant was dispersed in 300 ml of tetrahydrofuran, 50 g of modified nano-silicon dioxide was added, ultrasonic dispersion was performed, and the solvent was removed to obtain the flame retardant synergist. Example 1

[0040] A nano-silicon dioxide synergistic flame-retardant polypropylene composite material, comprising, by weight, 60 parts of PP resin, 15 parts of flame retardant (obtained in Preparation Example 1), 5 parts of flame retardant synergist (obtained in Preparation Example 2), 3 parts of flow modifier, 0.5 parts of anti-dripping agent, 0.3 parts of antioxidant 1010, and 0.5 parts of antioxidant 168;

[0041] Premixing PP resin, flame retardant, flame retardant synergist, anti-dripping agent and antioxidant for 3 minutes, adding flow modifier for secondary premixing for 5 minutes, and feeding the secondary premixed materials into a twin-screw extruder for extrusion granulation to obtain the polypropylene composite material;

[0042] The parameters of the twin-screw extruder are as follows: temperature settings: zone 1 110℃, zone 2 150℃, zone 3 165℃, zone 4 165℃, zone 5 165℃, zone 6 160℃, zone 7 160℃, zone 8 160℃, zone 9 165℃, die head 165℃; main engine speed: 30hz; main engine current: 150A; feeding speed: 10hz; vacuum: -0.07MPa. Example 2

[0043] The difference between this embodiment and embodiment 1 is that the flame retardant is 10 parts, and the rest is exactly the same as embodiment 1. Example 3

[0044] The difference between this embodiment and embodiment 1 is that the flame retardant is 20 parts, and the rest is exactly the same as embodiment 1. Example 4

[0045] The difference between this embodiment and embodiment 1 is that: 2 parts of flame retardant synergist are used, and the rest is exactly the same as embodiment 1. Example 5

[0046] The difference between this embodiment and embodiment 1 is that the flame retardant synergist is 8 parts, and the rest is exactly the same as embodiment 1. Example 6

[0047] The difference between this embodiment and embodiment 1 is that 50 parts of PP resin are used, and the rest of the parts are exactly the same as those in embodiment 1. Example 7

[0048] The difference between this embodiment and embodiment 1 is that: 70 parts of PP resin are used, and the rest of the parts are exactly the same as those in embodiment 1.

[0049] Comparative Example 1

[0050] The difference between this comparative example and Example 1 is that the flame retardant is 5 parts, and the rest is exactly the same as Example 1.

[0051] Comparative Example 2

[0052] The difference between this comparative example and Example 1 is that the flame retardant is 30 parts, and the rest is exactly the same as Example 1.

[0053] Comparative Example 3

[0054] The difference between this comparative example and Example 1 is that the flame retardant synergist is 0 parts, and the rest is exactly the same as Example 1.

[0055] Results and Testing

[0056] Tensile strength and elongation at break: refer to GB / T1040.1-2018 test, test conditions: 50mm / min;

[0057] Bending strength, bending modulus: refer to GB / T9341-2008, test conditions: 2mm / min;

[0058] Impact strength: Refer to GB / T 1843-2008 test, test conditions: 5.5J;

[0059] Melt index: refer to GB / T 3682-2018, test conditions: 230℃ / 2.16kg;

[0060] Limiting oxygen index determination: refer to GB 2406.2-2009 test, and the sample size is 120mm×6.5mm×3.2mm. The results are shown in Table 1.

[0061] Table 1

[0062]

[0063] From the data of Examples 1-7 in Table 1, it can be seen that the flame-retardant polypropylene composite material prepared by the present invention has excellent performance in tensile strength, elongation at break, flexural strength, impact strength, melt index and limiting oxygen index.

[0064] By comparing Example 1 and Comparative Example 1, it can be seen that as the amount of flame retardant decreases, the mechanical properties do not change much, but the flame retardant properties are significantly reduced.

[0065] By comparing Example 1 and Comparative Example 2, it can be seen that as the amount of flame retardant increases, the mechanical properties are significantly reduced, but the flame retardant properties do not change much.

[0066] By comparing Example 1 and Comparative Example 3, it can be seen that the flame retardant performance is greatly improved by adding a small amount of flame retardant synergist, which shows that the flame retardant and the flame retardant synergist produce obvious synergistic enhancement effects. At the same time, on this basis, the mechanical properties and melt index are also improved to a certain extent.

[0067] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A nano-silicon dioxide synergistic flame-retardant polypropylene composite material, characterized in that: Calculated by weight, it includes 50-70 parts of PP resin, 10-20 parts of flame retardant, 2-8 parts of flame retardant synergist, 1-5 parts of flow modifier, 0.2-0.8 parts of anti-drip agent, and 0.5-2 parts of antioxidant; The preparation method of the flame retardant is as follows: The phosphoamidation reaction of diphenylphosphinyl chloride and piperazine was carried out to obtain a phosphoamide derivative; The phosphonamide derivative is subjected to a ring-opening reaction with glycidyl methacrylate to obtain the flame retardant; The preparation method of the flame retardant synergist is as follows: Dispersing nano-silica in an ethanol-water solution, adding a silane coupling agent KH-570, and heating for reaction to obtain modified nano-silica; Dispersing the dendritic lubricant in tetrahydrofuran, adding modified nano-silicon dioxide, ultrasonically dispersing, and drying to obtain the flame retardant synergist; The dendritic lubricant is CYD-P214 produced by Weihai Chenyuan Molecular New Materials Co., Ltd.

2. The nano-silicon dioxide synergistic flame-retardant polypropylene composite material according to claim 1, characterized in that: The molar ratio of diphenylphosphine chloride to piperazine is 1:(0.9-1.1).

3. The nano-silicon dioxide synergistic flame-retardant polypropylene composite material according to claim 1, characterized in that: The molar ratio of the phosphonamide derivative to glycidyl methacrylate is 1:(0.9-1.1).

4. The nano-silicon dioxide synergistic flame-retardant polypropylene composite material according to claim 1, characterized in that: The mass ratio of the nano-silicon dioxide to KH-570 is 1:(0.1-0.2).

5. The nano-silicon dioxide synergistic flame-retardant polypropylene composite material according to claim 1, characterized in that: The mass of the dendritic lubricant and the modified nano-silicon dioxide is (1-2):

1.

6. The nano-silicon dioxide synergistic flame-retardant polypropylene composite material according to claim 1, characterized in that: The flow modifier is Elevast polymer modifier; the anti-drip agent is fluorine-containing polymer anti-drip agent; and the antioxidant is antioxidant 1010 and / or antioxidant 168.

7. A method for preparing the polypropylene composite material according to any one of claims 1 to 6, characterized in that: The steps include: The PP resin, flame retardant, flame retardant synergist, anti-dripping agent and antioxidant are premixed, and a flow modifier is added for secondary premixing. The secondary premixed materials are sent to a twin-screw extruder for extrusion granulation to obtain the polypropylene composite material.

8. The method for preparing the polypropylene composite material according to claim 7, characterized in that: The parameters of the twin-screw extruder are as follows: temperature settings: zone 1 110±10℃, zone 2 150±10℃, zone 3 165±10℃, zone 4 165±10℃, zone 5 165±10℃, zone 6 160±10℃, zone 7 160±10℃, zone 8 160±10℃, zone 9 165±10℃, die head 165±10℃; main engine speed: 30±3hz; main engine current: 150±10A; feeding speed: 10±2hz; vacuum: -0.07±0.03MPa.

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