Preparation method of low-smoke low-toxicity flame-retardant PP material

Abstract

The invention belongs to the technical field of modified plastics, and particularly relates to a preparation method of a low-smoke low-toxicity flame-retardant PP (polypropylene) material, which comprises the following steps: premixing the following raw materials in parts by weight: 50-100 parts of polypropylene, 50-100 parts of white oil, 20-100 parts of ammonium polyphosphate, 1-10 parts of silicon dioxide, 0.1-1 part of light stabilizer 770, 0.2-1 part of antioxidant, 0.2-0.8 part of polytetrafluoroethylene and 0.1-0.5 part of aluminum-magnesium crystal; the preparation method comprises the following steps: mixing the raw materials, carrying out extrusion granulation from an extruder after mixing is completed, and drying after granulation is completed, the extruder is a twin-screw extruder, the extrusion temperature is 140-200 DEG C, and the rotating speed of the extruder is 300-400 r / min. According to the invention, the addition of the aluminum-magnesium crystal and the silicon dioxide has a synergistic flame retardant effect, so that the PP has the effects of enhancing and toughening and improving the thermal stability; and meanwhile, the aluminum-magnesium crystal has a synergistic flame-retardant effect and smoke suppression performance when being used as a flame retardant for preparing flame-retardant PP (Polypropylene).

Description

Technical Field

[0001] The present invention relates to the technical field of modified plastics, and specifically to a preparation method of a low-smoke and low-toxicity flame-retardant PP material. Background Art

[0002] In recent years, the development of high-speed railways and subways across the country has been rapid. High-speed railway lines are almost all over the country, and the planning of urban subways in first- and second-tier cities has accelerated. Railway transportation has become a relatively common means of transportation in today's society. However, the subway and high-speed railway carriages are relatively enclosed. Once a fire breaks out, it is difficult to evacuate. If toxic smoke is released, it will cause difficulties for safer evacuation. Therefore, fire safety has become the top priority of railway transportation. According to the railway safety fire prevention standard EN45545, electronic and electrical products in contact with the power supply need to meet the R23 requirement, and the fire protection level reaches above HL3. The materials used for electronic and electrical appliances in contact with the power supply in railway transportation need to have a relatively high oxygen index. The higher the oxygen index of the material, the more difficult it is to burn; the electronic and electrical products in contact with the power supply need to have a relatively low smoke density, and less soot will be generated when in contact with the flame, which is convenient for rescue; the electronic and electrical products in contact with the power supply need to have a relatively low smoke toxicity. When in contact with the flame, the lower the smoke toxicity released, the safer it is in the enclosed carriage, and the lower the casualties caused by the fire.

[0003] Currently, the materials used for railway transportation electronic components are usually flame-retardant nylon, flame-retardant PC and other materials, but the cost is too high, the density is too heavy, and the smell is relatively large. Although the flame-retardant PP material is cheap and has a low density, the commonly used flame-retardant PP on the market generally has problems such as a low oxygen index (lower than 32), a high smoke density during combustion, and too high levels of toxic gases such as nitrogen oxides and bromides in the smoke. In addition, the smell of flame-retardant PP is relatively high, and the smell will inevitably escape during long-term use.

[0004] Therefore, according to the above technical problems, a preparation method of a low-smoke and low-toxicity flame-retardant PP material is designed. Utility Model Content

[0005] In order to make up for the problems of the existing technology, the present invention provides a preparation method of a low-smoke and low-toxicity flame-retardant PP material.

[0006] The technical solution adopted by the present invention to solve its technical problems is: a preparation method of a low-smoke and low-toxicity flame-retardant PP material, including the following steps: premix the following raw materials in parts by weight: 50-100 parts of polypropylene, 50-100 parts of white oil, 20-100 parts of ammonium polyphosphate, 1-10 parts of silicon dioxide, 0.1-1 part of light stabilizer 770, 0.2-1 part of antioxidant, 0.2-0.8 part of polytetrafluoroethylene, and 0.1-0.5 part of aluminum magnesium crystal; after mixing, extrude and pelletize from an extruder, and dry after pelletizing.

[0007] Preferably, the raw materials include 80-100 parts by weight of polypropylene, 60-100 parts by weight of white oil, 20-80 parts by weight of ammonium polyphosphate, 1-5 parts by weight of silicon dioxide, 0.1-1 part of light stabilizer 770, 0.5-1 part of antioxidant, 0.3-0.5 part of polytetrafluoroethylene, and 0.2-0.3 part of aluminummagnesium crystal, and the structural formula of the aluminummagnesium crystal is MgSO4·5Mg(OH)2·3H2O.

[0008] Preferably, the extruder is a twin-screw extruder, the extrusion temperature is 140°C-200°C, and the rotation speed of the extruder is 300-400 r / min.

[0009] Preferably, the temperatures of each section of the twin-screw extruder are successively: 150-155°C, 155-165°C, 175-185°C, 195-205°C, 195-205°C, 195-205°C, 175-185°C, 155-165°C, 155-165°C, 140-150°C.

[0010] Preferably, the drying step is to put the particles obtained after extrusion granulation into a forced-air drying oven for drying. The temperature of the forced-air drying oven is set at 80-100°C, and the drying time is 1.5-2.5 h.

[0011] Preferably, the degree of polymerization of the ammonium polyphosphate is greater than 2000.

[0012] Preferably, the melt flow rate of the polypropylene is 26.0 g / 10 min.

[0013] The advantages of the present invention are as follows:

[0014] 1. The flue gas generated by combustion in the present invention does not contain toxic gases such as nitrogen oxides and bromides.

[0015] 2. The addition of aluminummagnesium crystal and silicon dioxide in the present invention has a synergistic flame retardant effect, enabling the PP to have enhanced toughness and improved thermal stability. At the same time, the aluminummagnesium crystal itself, as a flame retardant, has a synergistic flame retardant effect and smoke suppression property when preparing flame retardant PP, and the combustion residue of silicon dioxide is in a flocculent shape, which is very beneficial for further improving the flame retardant performance of the material. Specific Embodiments

[0016] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the data such as tables in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0017] Source of reagents:

[0018] Polypropylene: K7926, Shanghai Secco Petrochemical Co., Ltd.;

[0019] N250 white oil, S-Oil Corporation;

[0020] Ammonium polyphosphate: degree of polymerization > 2000, Shandong Tianyi Chemical Co., Ltd.;

[0021] Silica: nanoscale, DuPont Company;

[0022] Light stabilizer 770: BASF Company;

[0023] Antioxidant 1010, Ciba Company;

[0024] Polytetrafluoroethylene: FA-500H, Daikin Fluorochemicals (China) Co., Ltd.;

[0025] Aluminum magnesium crystal: Shanghai Chuanzhu Industrial Co., Ltd.

[0026] Equipment model:

[0027] Twin-screw extruder: KS36, Kunshan Kexin Machinery Co., Ltd.;

[0028] Example 1:

[0029] The specific implementation method for making flame-retardant polypropylene is as follows: Mix the following raw materials by weight: 50 parts of polypropylene, 50 parts of N250 white oil, 20 parts of ammonium polyphosphate, 1 part of silica, 0.1 part of light stabilizer 770, 0.2 part of antioxidant 1010, 0.2 part of polytetrafluoroethylene, and 0.1 part of aluminum magnesium crystal; After mixing, extrude and pelletize from the extruder. The temperatures of each section of the twin-screw extruder are successively: 150 °C, 155 °C, 175 °C, 195 °C, 195 °C, 195 °C, 175 °C, 155 °C, 155 °C, 140 °C. The rotational speed of the twin-screw extruder is 300 r / min. Put the pellets obtained after extrusion granulation into a blast drying oven for drying. The temperature of the blast drying oven is set at 100 °C, the drying time is 1.5 h, the melt flow rate of the polypropylene is 26.0 g / 10 min, and the structural formula of the aluminum magnesium crystal is MgSO4·5Mg(OH)2·3H2O.

[0030] Example 2:

[0031] The specific implementation method of making flame-retardant polypropylene is as follows: the following raw materials are premixed by weight: 80 parts of polypropylene, 60 parts of N250 white oil, 20 parts of ammonium polyphosphate, 1 part of silicon dioxide, 0.1 parts of light stabilizer 7700, 0.5 parts of antioxidant 1010, 0.3 parts of polytetrafluoroethylene, and 0.2 parts of aluminum magnesium crystal. After the premixing is completed, granulation is carried out using a twin-screw extruder. The temperatures of each section of the twin-screw extruder are: 150°C, 155°C, 175°C, 195°C, 195°C, 175°C, 155°C, 155°C, and 140°C. The drying step is to put the particles obtained after extrusion granulation into a blast drying box for drying. The blast drying box is set at a temperature of 90°C, the drying time is 2h, the polypropylene melt flow rate is 26.0g / 10min, and the structural formula of the aluminum magnesium crystal is MgSO4·5Mg(OH)2·3H2O.

[0032] Example 3

[0033] The specific implementation method of making flame-retardant polypropylene is as follows: the following raw materials are premixed by weight: 70 parts of polypropylene, 50 parts of N250 white oil, 50 parts of ammonium polyphosphate, 5 parts of silicon dioxide, 0.5 parts of light stabilizer 770, 0.5 parts of antioxidant 1010, 0.4 parts of polytetrafluoroethylene, and 0.3 parts of aluminum magnesium crystal. After the premixing is completed, granulation is carried out using a twin-screw extruder. The temperatures of each section of the twin-screw extruder are: 150°C, 155°C, 175°C, 195°C, 195°C, 175°C, 155°C, 155°C, and 140°C. The drying step is to put the particles obtained after extrusion granulation into a blast drying box for drying. The blast drying box is set at a temperature of 90°C, the drying time is 2h, the polypropylene melt flow rate is 26.0g / 10min, and the structural formula of the aluminum magnesium crystal is MgSO4·5Mg(OH)2·3H2O.

[0034] Example 4

[0035] The specific implementation method for making flame-retardant polypropylene is as follows: the following raw materials are mixed by weight: 100 parts of polypropylene, 100 parts of N250 white oil, 100 parts of ammonium polyphosphate, 0 parts of silicon dioxide, 1 part of light stabilizer 770, 1 part of antioxidant 1010 1 part, 0.8 part of polytetrafluoroethylene and 0.5 part of aluminum-magnesium crystal are premixed, and after the premixing is completed, a twin-screw extruder is used for granulation, and the temperatures of each section of the twin-screw extruder are: 155°C, 165°C, 185°C, 205°C, 205°C, 185°C, 165°C, 165°C, 150°C in sequence, and the drying step is to put the particles obtained after extrusion granulation into a blast drying oven for drying, the blast drying oven is set at a temperature of 100°C, the drying time is 1.5h, the polypropylene melt flow rate is 26.0g / 10min, and the structural formula of the aluminum-magnesium crystal is MgSO4·5Mg(OH)2·3H2O.

[0036] Example 5

[0037] The specific implementation method of making flame retardant polypropylene is as follows: the following raw materials are mixed by weight: the raw materials include 100 parts of polypropylene, 100 parts of N250 white oil, 80 parts of ammonium polyphosphate, 5 parts of silicon dioxide, 1 part of light stabilizer 770, 1 part of antioxidant 1010 1 part, 0.5 part of polytetrafluoroethylene and 0.3 part of aluminum-magnesium crystal are premixed, and after the premixing, a twin-screw extruder is used for granulation, and the temperatures of each section of the twin-screw extruder are: 155°C, 165°C, 185°C, 205°C, 205°C, 185°C, 165°C, 165°C, 150°C in sequence, and the drying step is to put the particles obtained after extrusion granulation into a blast drying oven for drying, the blast drying oven is set at a temperature of 100°C, the drying time is 1.5h, the polypropylene melt flow rate is 26.0g / 10min, and the structural formula of the aluminum-magnesium crystal is MgSO4·5Mg(OH)2·3H2O.

[0038] Comparative Example:

[0039] The ratios of Comparative Example 1 and Example 5 are the same except that they do not contain silicon dioxide, and the preparation methods are also the same;

[0040] The ratios of Comparative Example 2 and Example 5 are the same except that they do not contain aluminum-magnesium crystals, and the preparation methods are also the same;

[0041] Performance test: The samples prepared from the low-smoke and low-toxic flame-retardant PP material prepared in the embodiment and the flame-retardant PP material obtained in the comparative embodiment were tested. The specific test method is as follows:

[0042] Flame retardant grade: tested according to standard UL94-2013 method;

[0043] Oxygen index: Tested according to the method of standard ISO 4589-2-2017;

[0044] Toxicity of flue gas: Tested according to NF X-70-100-1-2006 and NF X70-100-2-2006 in standard EN45545-2006 at 600 °C to obtain the toxicity index of the material. The specific data is shown in Table 1. Tensile property test: Tested according to ASTM D638-2010 with a tensile rate of 50 mm / min; Flexural property test: Tested according to ASTM D790-2010 with a flexural rate of 2 mm / min.

[0045] Izod notched impact strength was tested according to ASTM D256-2010 at 23 °C with a V-notch and an impact energy of 2.75 J. Melt mass flow rate was tested according to ASTM D1238-2010 at 230 °C with a load of 2.16 kg. The specific data is shown in Table 2.

[0046] Table 1

[0047]

[0048] It can be seen from Table 1 above that the flame retardancy grades of Examples 1 to 5 in the present invention can all reach V-0 level, while the flame retardancy energy levels of Comparative Example 1 and Comparative Example 2 cannot reach V-2. At the same time, through the examples and comparative examples, it can be seen that aluminum magnesium crystal and silica have a synergistic flame retardant effect, and neither can be absent. Without any one of the components, the flame retardancy grade, oxygen index and flue gas toxicity index will be much worse.

[0049] Table 2

[0050]

[0051] It can be seen from Table 2 that the specimens prepared in Examples 1-5 have better mechanical properties than those of Comparative Example 1 and Comparative Example 2. At the same time, the thermal stability is better than that of Comparative Example 1 and Comparative Example 2. At the same time, it can be seen that aluminum magnesium crystal and silica have a synergistic flame retardant effect, and neither can be absent.

[0052] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

Claims

1. A preparation method of a low-smoke and low-toxicity flame-retardant PP material, characterized in that, It includes the following steps: premix the following raw materials by weight parts: 50 - 100 parts of polypropylene, 50 - 100 parts of white oil, 20 - 100 parts of ammonium polyphosphate, 1 - 10 parts of silicon dioxide, 0.1 - 1 part of light stabilizer 770, 0.2 - 1 part of antioxidant, 0.2 - 0.8 part of polytetrafluoroethylene, and 0.1 - 0.5 part of aluminum-magnesium crystal; after mixing is completed, extrude and pelletize from an extruder, and dry after pelletizing is completed.

2. The preparation method of a low-smoke and low-toxicity flame-retardant PP material according to claim 1, characterized in that: The raw materials include, by weight parts, 80 - 100 parts of polypropylene, 60 - 100 parts of white oil, 20 - 80 parts of ammonium polyphosphate, 1 - 5 parts of silicon dioxide, 0.1 - 1 part of light stabilizer 770, 0.5 - 1 part of antioxidant, 0.3 - 0.5 part of polytetrafluoroethylene, and 0.2 - 0.3 part of aluminum-magnesium crystal.

3. The preparation method of a low-smoke and low-toxicity flame-retardant PP material according to claim 1, characterized in that: The extruder is a twin-screw extruder, the extrusion temperature is 140°C - 200°C, and the rotational speed of the extruder is 300 - 400 r / min.

4. The preparation method of a low-smoke and low-toxicity flame-retardant PP material according to claim 3, characterized in that: The temperatures of each section of the twin-screw extruder are in sequence: 150 - 155°C, 155 - 165°C, 175 - 185°C, 195 - 205°C, 195 - 205°C, 195 - 205°C, 175 - 185°C, 155 - 165°C, 155 - 165°C, 140 - 150°C.

5. The preparation method of a low-smoke and low-toxicity flame-retardant PP material according to claim 1, characterized in that: The drying step is to put the particles obtained after extrusion and pelletizing into a forced-air drying oven for drying. The temperature of the forced-air drying oven is set at 80 - 100°C, and the drying time is 1.5 - 2.5 h.

6. The preparation method of a low-smoke and low-toxicity flame-retardant PP material according to claim 1, characterized in that: The degree of polymerization of the ammonium polyphosphate is greater than 2000.

7. The preparation method of a low-smoke and low-toxicity flame-retardant PP material according to claim 1, characterized in that: The melt flow rate of the polypropylene is 26.0 g / 10 min.

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