Antistatic polypropylene masterbatch and preparation method thereof

Abstract

The present application relates to the technical field of functional polypropylene masterbatch, and more specifically, it relates to an antistatic polypropylene masterbatch and a preparation method thereof. An antistatic polypropylene masterbatch comprises the following raw materials in parts by mass: 79-87 parts of polypropylene, 10-15 parts of conductive agent, 1-2 parts of auxiliary agent, 1-2 parts of antioxidant and 1-2 parts of stabilizer, wherein the conductive agent is salicylaldehyde bis-Schiff base-copper complex, and the preparation method of salicylaldehyde bis-Schiff base-copper complex is: adding salicylaldehyde-toluene solution dropwise to ethylenediamine-toluene solution to react, thereby obtaining bis-salicylaldehyde-ethylenediamine Schiff base; adding methanol-copper sulfate solution dropwise to bis-salicylaldehyde-ethylenediamine Schiff base-methanol solution to react, thereby obtaining salicylaldehyde bis-Schiff base-copper complex. After the antistatic polypropylene masterbatch of the present application is added to the polypropylene product, the polypropylene product will have better antistatic and antioxidant properties.

Description

Technical Field

[0001] The present application relates to the technical field of functional polypropylene masterbatch, and more specifically, to an antistatic polypropylene masterbatch and a preparation method thereof. Background Art

[0002] Polypropylene is a semi-crystalline thermoplastic polymer made from propylene monomers through addition polymerization. It is non-toxic, odorless, transparent in appearance and lightweight. It also has excellent mechanical properties, heat resistance, chemical resistance and easy molding. Therefore, it is widely used in industries such as automobiles, home appliances, medical devices, packaging coatings, home clothing and construction.

[0003] However, polypropylene still has the characteristics of small molecular polarity and poor water absorption, so it also has strong electrical insulation, with a surface resistivity of 10 16 Ω·m, and then it is easy to accumulate static electricity due to friction or peeling during production and use, which will lead to static electricity hazards such as dust absorption, discharge, breakdown, and even combustion or explosion. Therefore, there is an urgent need for an antistatic polypropylene masterbatch to improve the antistatic performance of polypropylene products. Summary of the invention

[0004] In order to improve the antistatic performance of polypropylene, the present application provides an antistatic polypropylene masterbatch and a preparation method thereof.

[0005] In the first aspect, the present application provides an antistatic polypropylene masterbatch, which adopts the following technical solution:

[0006] An antistatic polypropylene masterbatch comprises the following raw materials in parts by weight: 79-87 parts of polypropylene, 10-15 parts of a conductive agent, 1-2 parts of an auxiliary agent, 1-2 parts of an antioxidant and 1-2 parts of a stabilizer, wherein the conductive agent is a salicylaldehyde bis-Schiff base-copper complex.

[0007] Schiff base is a kind of organic compound containing imine C=N or azomethine C=NH characteristic groups. The C=N bond inside it and its adjacent carbon-carbon double bond will form a conjugated system, allowing electrons to move freely between molecules, thereby achieving conductivity. After the Schiff base is embedded inside the polypropylene, a conductive network will be formed inside the polypropylene, thereby effectively improving the antistatic performance of the polypropylene masterbatch.

[0008] However, the conjugated molecular weight of a single Schiff base polymer is tightly packed through the π-π interaction, resulting in fewer ion diffusion channels and redox active sites, making its electrochemical performance unable to reach an ideal state. 2+ Then a charge transfer complex can be formed, which can further enhance the electron transmission ability and further improve the antistatic performance of polypropylene masterbatch.

[0009] In addition, due to the addition of oxidants and additives, the polypropylene masterbatch has extremely good dispersibility and weather resistance.

[0010] Preferably, the preparation method of the salicylaldehyde bis-Schiff base-copper complex comprises the following steps:

[0011] Preparation of disalicylicaldehyde-ethylenediamine Schiff base: slowly drop the salicylaldehyde-toluene solution into the ethylenediamine-toluene solution, stirring while dropping, then heating to reflux, reacting for 3-5 hours, generating a large amount of golden yellow precipitate, cooling, filtering, washing and drying to obtain disalicylicaldehyde-ethylenediamine Schiff base;

[0012] Preparation of salicylaldehyde bis-Schiff base-copper complex: Slowly add methanol-copper sulfate solution to bis-salicylaldehyde-ethylenediamine Schiff base-methanol solution, stirring while adding, then heat to reflux, react for 3-5 hours, cool, filter, wash and dry to obtain salicylaldehyde bis-Schiff base-copper complex.

[0013] Preferably, the molar ratio of salicylaldehyde, ethylenediamine and copper sulfate is (1-3): (1-3): 1.

[0014] Preferably, the antioxidant is one or a mixture of butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite.

[0015] Preferably, the antioxidant is a mixture of n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite.

[0016] The aging of polypropylene is an important factor affecting its performance, and the addition of antioxidants has a significant effect on inhibiting and delaying the oxidation and degradation of polypropylene. Currently, substituted phenols, phosphites, sulfur-containing esters, aromatic amines, etc. are widely used. Among them, commonly used phenolic antioxidants include butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester. In order to obtain better antioxidant properties, tris(2,4-di-tert-butylphenyl) phosphite is usually added as an auxiliary antioxidant to obtain a synergistic effect. Among them, the synergistic effect of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester and tris(2,4-di-tert-butylphenyl) phosphite is the most prominent.

[0017] The reason is that β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate is mainly effective in the initial stage of the oxidation reaction, inhibiting the initiation of the oxidation chain reaction by capturing free radicals, while tri(2,4-di-tert-butylphenyl) phosphite focuses on decomposing the hydroperoxides produced during the oxidation process to prevent the spread of the oxidation reaction. The combination of the two starts from different links of the oxidation reaction to form a more comprehensive antioxidant system.

[0018] Preferably, the mass ratio of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate to tris(2,4-di-tert-butylphenyl) phosphite is (1-2):(1-2).

[0019] Preferably, the mass ratio of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate to tris(2,4-di-tert-butylphenyl) phosphite is 1:2.

[0020] Artificial antioxidants are basically fat-soluble compounds. When they come into contact with liquids with high oil content, based on the principle of like dissolves like, antioxidants can easily migrate out, thus affecting the antioxidant properties of polypropylene. Among β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite has a larger molecular weight, and its spatial symmetry and central phosphite group make the molecule itself weakly polar, which in turn makes the migration of tris(2,4-di-tert-butylphenyl) phosphite more resistant.

[0021] In other words, in the mixture of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite, when the proportion of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate is larger, the antioxidant performance of the antioxidant is better; when the proportion of tris(2,4-di-tert-butylphenyl) phosphite is larger, the migration resistance of the antioxidant is better.

[0022] Preferably, the mass ratio of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate to tris(2,4-di-tert-butylphenyl) phosphite is 2:1, and the antioxidant and the conductive agent are combined to form a combination for use. The preparation method of the combination is: first, the antioxidant is added to an equal amount of toluene, and then the conductive agent is added and continuously stirred, and finally dried and ground to obtain the combination.

[0023] Salicylaldehyde bis-Schiff base-copper complex has a porous mesoporous structure and its surface has excellent lipophilic properties. Therefore, when the antioxidant is used in combination with the conductive agent, the antioxidant can be loaded in the pores of the salicylaldehyde bis-Schiff base-copper complex, thereby ensuring the antioxidant performance of the antioxidant and enabling the antioxidant to obtain extremely excellent anti-migration performance with the cooperation of the salicylaldehyde bis-Schiff base-copper complex.

[0024] Preferably, the stabilizer is magnesium stearate, and the auxiliary agent is silane coupling agent KH-550.

[0025] In a second aspect, the present application provides a method for preparing an antistatic polypropylene masterbatch, using the following technical solution:

[0026] A method for preparing an antistatic polypropylene masterbatch comprises the following steps: firstly, polypropylene, a conductive agent, an auxiliary agent, an antioxidant and a stabilizer are added into a mixer according to a mass ratio, mixed at a temperature of 100-120°C for 10-20 minutes, and then the mixture is added into a twin-screw extruder, and granulated by melt extrusion to obtain the antistatic polypropylene masterbatch.

[0027] In summary, this application has the following beneficial effects:

[0028] 1. After the Schiff base is embedded in the polypropylene, a conductive network will be formed inside the polypropylene, thereby effectively improving the antistatic performance of the polypropylene masterbatch. However, the single Schiff base polymer conjugated molecular weight is tightly stacked through the π-π action, resulting in fewer ion diffusion channels and redox active sites, making its electrochemical performance unable to reach the ideal state. 2+ Then a charge transfer complex can be formed, which can further enhance the electron transmission ability and further improve the antistatic performance of polypropylene masterbatch.

[0029] 2. Commonly used phenolic antioxidants include butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester. In order to obtain better antioxidant properties, tris(2,4-di-tert-butylphenyl) phosphite is usually added as an auxiliary antioxidant to obtain a synergistic effect. Among them, the synergistic effect of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester and tris(2,4-di-tert-butylphenyl) phosphite is the most prominent.

[0030] The reason is that β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate is mainly effective in the initial stage of the oxidation reaction, inhibiting the initiation of the oxidation chain reaction by capturing free radicals, while tri(2,4-di-tert-butylphenyl) phosphite focuses on decomposing the hydroperoxides produced during the oxidation process to prevent the spread of the oxidation reaction. The combination of the two starts from different links of the oxidation reaction to form a more comprehensive antioxidant system.

[0031] 3. Artificial antioxidants are basically fat-soluble compounds. When they come into contact with liquids with high oil content, based on the principle of like dissolves like, antioxidants can easily migrate out, thus affecting the antioxidant properties of polypropylene. Among β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite has a larger molecular weight, and its spatial symmetry and central phosphite group make the molecule itself weakly polar, thereby causing greater resistance to the migration of tris(2,4-di-tert-butylphenyl) phosphite. In other words, in actual use, staff can increase the amount of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite according to actual needs, so as to obtain better antioxidant or anti-migration properties.

[0032] 4. Salicylaldehyde bis-Schiff base-copper complex has a porous mesoporous structure and its surface has excellent lipophilic properties. Therefore, when the antioxidant is used in combination with the conductive agent, the antioxidant can be loaded in the pores of the salicylaldehyde bis-Schiff base-copper complex, thereby ensuring the antioxidant properties of the antioxidant and, in combination with the salicylaldehyde bis-Schiff base-copper complex, enabling the antioxidant to obtain extremely excellent anti-migration properties. DETAILED DESCRIPTION

[0033] The present application is further described in detail below in conjunction with Examples 1-8 and Comparative Example 1.

[0034] raw material

[0035] Polypropylene Formosa Plastics PP1080; toluene, methanol, salicylaldehyde Beijing Inokai; ethylenediamine Alfa Aesar (China); magnesium stearate, copper sulfate Shanghai Macklin; β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite Signma-Aldrich; silane coupling agent KH-550 Nanjing Xuanhao.

[0036] Example 1

[0037] An antistatic polypropylene masterbatch comprises the following raw materials: 85g polypropylene, 13g conductive agent, 1.5g auxiliary agent, 1.5g antioxidant and 1.5g stabilizer;

[0038] Wherein, the auxiliary agent is silane coupling agent KH-550, the stabilizer is magnesium stearate, the antioxidant is a mixture of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite, and the mass ratio of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate to tris(2,4-di-tert-butylphenyl) phosphite is 1:1;

[0039] The conductive agent is salicylaldehyde bis-Schiff base-copper complex, and the preparation method of salicylaldehyde bis-Schiff base-copper complex comprises the following steps:

[0040] Preparation of disalicylicaldehyde-ethylenediamine Schiff base: slowly drop the salicylaldehyde-toluene solution into the ethylenediamine-toluene solution while stirring, then heat to reflux, react for 4 hours, generate a large amount of golden yellow precipitate, cool, filter, wash and dry to obtain disalicylicaldehyde-ethylenediamine Schiff base;

[0041] Preparation of salicylaldehyde bis-Schiff base-copper complex: Slowly add methanol-copper sulfate solution to bis-salicylaldehyde-ethylenediamine Schiff base-methanol solution while stirring, then heat to reflux, react for 4 hours, cool, filter, wash and dry to obtain salicylaldehyde bis-Schiff base-copper complex.

[0042] In the preparation of salicylaldehyde bis-Schiff base-copper complex, the molar ratio of salicylaldehyde, ethylenediamine and copper sulfate is 2:2:1, and toluene and methanol are used as solvents in an excess amount.

[0043] The steps of the preparation method of antistatic polypropylene masterbatch are as follows: first, polypropylene, conductive agent, additive, antioxidant and stabilizer are added into a mixer according to mass proportion, mixed at a temperature of 110° C. for 15 minutes, and then the mixture is added into a twin-screw extruder, and granulated by melt extrusion to obtain antistatic polypropylene masterbatch.

[0044] Example 2-Example 3

[0045] The difference from Example 1 is that the molar ratios of salicylaldehyde, ethylenediamine and copper sulfate are different, as shown in Table 1.

[0046] Table 1 Molar ratio of salicylaldehyde, ethylenediamine and copper sulfate in Examples 1 to 3

[0047] Example 1 Example 2 Example 3 Salicylaldehyde 2 1 3 Ethylenediamine 2 3 1 Copper sulfate 1 1 1

[0048] Example 4

[0049] The difference from Example 1 is that the antioxidant is only n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0050] Example 5

[0051] The difference from Example 1 is that the antioxidant is only tris(2,4-di-tert-butylphenyl)phosphite.

[0052] Example 6-Example 7

[0053] The difference from Example 1 is that the mass ratio of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite is different, as shown in Table 2.

[0054] Table 2 Mass ratio of each component of antioxidant in Example 1, Example 6 and Example 7

[0055]

[0056] Example 8

[0057] The difference from Example 7 is that the antioxidant and the conductive agent are combined to form a combination for use, and the preparation method of the combination is: first, the antioxidant is added to an equal amount of toluene, then the conductive agent is added and continuously stirred, and finally, the combination is dried and ground to obtain the combination.

[0058] Comparative Example 1

[0059] The difference from Example 1 is that no conductive agent is added.

[0060] Performance testing

[0061] 1. Conductive performance test

[0062] Three samples were taken from Examples 1 to 3 and Comparative Example 1, respectively, and then added to polypropylene at a dosage of 4 wt%. The resistivity of the samples was then tested in accordance with GB / T 15662-1995 "Test method for volume resistivity of conductive and antistatic plastics" and the average value was taken.

[0063] The test data are shown in Table 3.

[0064] Table 3 Resistivity of Example 1 to Example 3 and Comparative Example 1 / Ω·m

[0065] Example 1 Example 2 Example 3 Comparative Example 1 Resistivity Ω·m <![CDATA[3.7×10 8 ]]> <![CDATA[1.2×10 9 ]]> <![CDATA[8.6×10 8 ]]> <![CDATA[3.3×10 16 ]]>

[0066] 2. Antioxidant performance test

[0067] Six samples were taken from Example 1 and Example 4 to Example 8, and then added to polypropylene at an addition amount of 4 wt %. The notched impact strength of three of the samples was tested with reference to GB / T1843-2008 "Determination of Izod Impact Strength of Plastics", and recorded as the original notched impact strength and the average value was taken;

[0068] The other three samples were then subjected to a 2000 h accelerated light aging test using a xenon arc lamp with a light irradiation intensity of 0.5 W / m 2 ,After that, the notched impact strength test is performed, recorded as the aged notched impact strength and the average value is taken, and finally the antioxidant value is calculated. The test data are shown in Table 5.

[0069] Antioxidation value = (original notched impact strength - aged notched impact strength) / original notched impact strength.

[0070] 2. Anti-migration performance test

[0071] Three samples were taken from Example 1 and Example 4 to Example 8, respectively. The samples were then immersed in olive oil for 24 hours. The total concentration of antioxidant substances in the olive oil was then calculated and the average value was taken. The test data are shown in Table 4.

[0072] Table 4 Antioxidant performance and anti-migration performance of Example 1 and Example 4-Example 7

[0073] Antioxidant Value Oxidant concentration (mg / L) Example 1 25.7％ 2676 Example 4 27.3％ 3211 Example 5 39.1％ 2163 Example 6 27.0％ 2399 Example 7 22.9％ 2864 Example 8 22.5％ 2292

[0074] Referring to Example 1 and Comparative Example 1 and in combination with Table 3, it can be seen that the resistivity of Example 1 is significantly reduced compared with Comparative Example 1, which indicates that the use of salicylaldehyde bis-Schiff base-copper complex can significantly improve the antistatic properties of polypropylene.

[0075] The reason is that Schiff base is a kind of organic compound containing imine C=N or azomethine C=NH characteristic groups. The C=N bond inside it and its adjacent carbon-carbon double bond will form a conjugated system, allowing electrons to move freely between molecules, thereby achieving conductivity. After the Schiff base is embedded inside the polypropylene, a conductive network will be formed inside the polypropylene, thereby effectively improving the antistatic performance of the polypropylene masterbatch.

[0076] However, the conjugated molecular weight of a single Schiff base polymer is tightly packed through the π-π interaction, resulting in fewer ion diffusion channels and redox active sites, making its electrochemical performance unable to reach an ideal state. 2+ Then a charge transfer complex can be formed, which can further enhance the electron transmission ability and further improve the antistatic performance of polypropylene masterbatch.

[0077] With reference to Examples 1 to 3 and in combination with Table 3, it can be seen that, relative to Example 1, the conductivity of Examples 2 and 3 increases to a certain extent, which indicates that when the components of the salicylaldehyde bis-Schiff base-copper complex adopt the proportions of Example 1, the prepared salicylaldehyde bis-Schiff base-copper complex will enable the polypropylene masterbatch to have a better antistatic performance improvement effect.

[0078] With reference to Example 1 and Example 4-Example 5 and in combination with Table 4, it can be seen that among Example 4 and Example 5, the antioxidant value of Example 4 is relatively low, but compared with Example 1, the antioxidant value of Example 4 is still relatively high.

[0079] This shows that both β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite can promote polypropylene to obtain extremely excellent antioxidant properties, among which β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate has a more prominent improvement effect. However, compared with the use of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate or tris(2,4-di-tert-butylphenyl) phosphite alone, the combined use of the two can further improve the antioxidant properties of polypropylene.

[0080] The reason is that β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate is mainly effective in the initial stage of the oxidation reaction, inhibiting the initiation of the oxidation chain reaction by capturing free radicals, while tri(2,4-di-tert-butylphenyl) phosphite focuses on decomposing the hydroperoxides produced during the oxidation process to prevent the spread of the oxidation reaction. The combination of the two starts from different links of the oxidation reaction to form a more comprehensive antioxidant system.

[0081] In addition, in Example 4 and Example 5, the oxidant concentration of Example 5 is relatively lower, and the oxidant concentration of Example 5 is still lower than that of Example 1, which shows that the combined use of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite has no promoting effect on the anti-migration performance of the antioxidant, and the anti-migration performance of tris(2,4-di-tert-butylphenyl) phosphite is more prominent.

[0082] The reason is that artificial antioxidants are basically fat-soluble compounds. When they come into contact with liquids with high oil content, based on the principle of like dissolves like, the antioxidants can easily migrate out. Tris(2,4-di-tert-butylphenyl) phosphite has a large molecular weight, and its spatial symmetry and central phosphite group make the molecule itself weakly polar, which in turn causes tris(2,4-di-tert-butylphenyl) phosphite to encounter greater resistance to migration.

[0083] Referring to Example 1 and Example 6-Example 7 and in combination with Table 4, it can be seen that the oxidant concentration of Example 6 is relatively lower than that of Example 1, and the antioxidant value of Example 6 is still lower than that of Example 4 using β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate as an antioxidant. The antioxidant value of Example 7 is relatively lower, and the oxidant concentration of Example 7 is still lower than that of Example 4 using β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate as an antioxidant.

[0084] This shows that in the mixture of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite, when the proportion of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate is larger, the antioxidant performance of the antioxidant is better; when the proportion of tris(2,4-di-tert-butylphenyl) phosphite is larger, the migration resistance of the antioxidant is better. In actual use, the staff can give a preference according to actual needs to obtain better antioxidant performance or anti-migration performance.

[0085] Referring to Example 7-Example 8 and combining with Table 4, it can be seen that, relative to Example 7, the antioxidant value of Example 8 is slightly reduced, and the oxidant concentration of Example 8 is significantly reduced. This shows that when the antioxidant and the conductive agent are combined to form a combination for use, the prepared polypropylene masterbatch will enable the polypropylene product to obtain better antistatic and anti-migration properties.

[0086] The reason is that salicylaldehyde bis-Schiff base-copper complex has a porous mesoporous structure and its surface has excellent lipophilic properties. Therefore, when the antioxidant is used in combination with the conductive agent, the antioxidant can be loaded in the pores of the salicylaldehyde bis-Schiff base-copper complex, thereby ensuring the antioxidant properties of the antioxidant and, with the cooperation of the salicylaldehyde bis-Schiff base-copper complex, enabling the antioxidant to obtain extremely excellent anti-migration properties.

[0087] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. An antistatic polypropylene masterbatch, characterized in that: The invention comprises the following raw materials in parts by weight: 79-87 parts of polypropylene, 10-15 parts of a conductive agent, 1-2 parts of an auxiliary agent, 1-2 parts of an antioxidant and 1-2 parts of a stabilizer, wherein the conductive agent is a salicylaldehyde bis-Schiff base-copper complex.

2. The antistatic polypropylene masterbatch according to claim 1, characterized in that: The preparation method of the salicylaldehyde bis-Schiff base-copper complex comprises the following steps: Preparation of disalicylicaldehyde-ethylenediamine Schiff base: slowly drop the salicylaldehyde-toluene solution into the ethylenediamine-toluene solution, stirring while dropping, then heating to reflux, reacting for 3-5 hours, generating a large amount of golden yellow precipitate, cooling, filtering, washing and drying to obtain disalicylicaldehyde-ethylenediamine Schiff base; Preparation of salicylaldehyde bis-Schiff base-copper complex: Slowly add methanol-copper sulfate solution to bis-salicylaldehyde-ethylenediamine Schiff base-methanol solution, stirring while adding, then heat to reflux, react for 3-5 hours, cool, filter, wash and dry to obtain salicylaldehyde bis-Schiff base-copper complex.

3. The antistatic polypropylene masterbatch according to claim 2, characterized in that: The molar ratio of salicylaldehyde, ethylenediamine and copper sulfate is (1-3): (1-3):

1.

4. The antistatic polypropylene masterbatch according to claim 1, characterized in that: The antioxidant is one or a mixture of butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite.

5. The antistatic polypropylene masterbatch according to claim 4, characterized in that: The antioxidant is a mixture of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and tris(2,4-di-tert-butylphenyl) phosphite.

6. The antistatic polypropylene masterbatch according to claim 5, characterized in that: The mass ratio of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate to tris(2,4-di-tert-butylphenyl) phosphite is (1-2):(1-2).

7. The antistatic polypropylene masterbatch according to claim 6, characterized in that: The mass ratio of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate to tris(2,4-di-tert-butylphenyl) phosphite is 1:

2.

8. The antistatic polypropylene masterbatch according to claim 6, characterized in that: The mass ratio of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate to tris(2,4-di-tert-butylphenyl) phosphite is 2:1, and the antioxidant and the conductive agent are combined to form a combination for use. The preparation method of the combination is: first, the antioxidant is added to an equal amount of toluene, and then the conductive agent is added and continuously stirred, and finally dried and ground to obtain the combination.

9. The antistatic polypropylene masterbatch according to claim 1, characterized in that: The stabilizer is magnesium stearate, and the auxiliary agent is silane coupling agent KH-550.

10. A method for preparing the antistatic polypropylene masterbatch according to any one of claims 1 to 9, characterized in that: The steps are as follows: firstly, polypropylene, conductive agent, auxiliary agent, antioxidant and stabilizer are added into a mixer according to mass proportion, mixed at a temperature of 100-120°C for 10-20 minutes, and then the mixture is added into a twin-screw extruder, and granulated by melt extrusion to obtain antistatic polypropylene masterbatch.

Images