An acid-resistant, antistatic polyethylene inner liner composition

Abstract

The application provides an acid-resistant antistatic polyethylene lining plate composition which is composed of the following components in parts by weight: polyethylene, 60-80 parts; polyvinylidene fluoride, 15-30 parts; crosslinking agent, 0.5-1 part; auxiliary crosslinking agent, 1-3 parts; EVA resin, 3-6 parts; fluorocarbon surfactant, 3-5 parts; fluorosilicon modified resin, 15-20 parts; fluorinated ethylene propylene, 5-10 parts; antioxidant, 0.2-0.5 parts. The formula is tightly combined by the crosslinking agent, the auxiliary crosslinking agent, the polyethylene and the fluorocarbon surfactant under the action of the crosslinking agent, and the fluorocarbon surfactant is distributed in the polyethylene resin, so that the permanent acid resistance, the antistatic property and the strength of the composition are improved, and the problem that the acid-resistant antistatic stainless steel kettle lining is difficult to process is solved.

Description

Technical Field

[0001] This invention belongs to the field of polymer material processing and application, specifically relating to an acid-resistant and antistatic polyethylene liner composition to solve the problem of difficult processing of acid-resistant and antistatic stainless steel reactor liner. Background Technology

[0002] Large stainless steel storage tanks are mainly used for storing liquid crude oil and naphtha. However, the inside of these tanks is easily corroded by acidic substances in the crude oil. Therefore, a layer of anti-corrosion plastic material needs to be laid inside the tank. This material needs to have certain antistatic properties, corrosion resistance, and acid resistance. Currently, polytetrafluoroethylene (PTFE) is commonly used because it has good corrosion resistance and stable performance. However, PTFE has a high melting temperature, is difficult to process and weld, and is expensive, resulting in high lining costs.

[0003] To address the aforementioned issues, this invention employs polyethylene crosslinking to enhance strength and heat resistance, and utilizes the synergistic effects of various functional additives to achieve acid resistance and antistatic properties. Summary of the Invention

[0004] This invention relates to an acid-resistant and antistatic polyethylene liner composition. The matrix resin of the composition is polyethylene and polyvinylidene fluoride, and in addition to crosslinking agents and co-crosslinking agents, it also contains a certain amount of fluorocarbon surfactants.

[0005] As described above, in an acid-resistant and antistatic polyethylene liner composition, the polyethylene is high-density polyethylene.

[0006] As described above, the acid-resistant and antistatic polyethylene lining composition further comprises, by weight parts: polyethylene, 60-80 parts; polyvinylidene fluoride, 15-30 parts; crosslinking agent, 0.5-1 part; co-crosslinking agent, 1-3 parts; and fluorocarbon surfactant, 3-5 parts.

[0007] In the aforementioned acid-resistant and antistatic polyethylene liner composition, the fluorocarbon surfactant is an ammonium oxide-type multifunctional fluorocarbon surfactant; the co-crosslinking agent is preferably triallyl cyanurate.

[0008] As described above, the acid-resistant and antistatic polyethylene liner composition further contains a certain amount of fluorinated ethylene propylene and fluorosilicone modified resin.

[0009] As described above, the acid-resistant and antistatic polyethylene liner composition further includes, wherein the fluorinated ethylene propylene is a copolymer of hexafluoropropylene and tetrafluoroethylene.

[0010] In the above-mentioned acid-resistant and antistatic polyethylene liner composition, the amount of fluorinated ethylene propylene is 5-10 parts by weight, and the amount of fluorosilicone modified resin is 15-20 parts by weight.

[0011] The acid-resistant and antistatic polyethylene liner composition described above further contains 3-6 parts of EVA resin and may contain 0.2-0.5 parts of antioxidant as needed.

[0012] As in the above-mentioned acid-resistant and antistatic polyethylene inner lining composition, the vinyl acetate content of the EVA resin is ≤5%; the antioxidant is a mixture of hindered phenolic and phosphite antioxidants in a mixing mass ratio of 1:1.

[0013] The preparation method of the acid-resistant and antistatic polyethylene inner lining board composition described above includes the following steps:

[0014] (1) Weigh out polyethylene, antioxidant, fluorocarbon surfactant, crosslinking agent, and crosslinking aid according to the formula ratio, put them into a high-speed mixer and mix at high speed, then release the material for later use;

[0015] (2) Put polyvinylidene fluoride, the material treated in step (1), EVA resin, fluorinated ethylene propylene, and fluorosilicone modified resin into a high-speed mixer and mix them. Then release the material to obtain an acid-resistant and antistatic polyethylene inner lining board composition.

[0016] (3) The acid-resistant and antistatic composition is reactively extruded in a twin-screw extruder at a temperature of 180-230℃ to obtain an acid-resistant and antistatic polyethylene inner liner.

[0017] Preferably, the technical solution of the present invention can be as follows:

[0018] An acid-resistant and antistatic polyethylene lining composition comprises the following components in parts by weight: polyethylene, 60-80 parts; polyvinylidene fluoride, 15-30 parts; crosslinking agent, 0.5-1 part; co-crosslinking agent, 1-3 parts; EVA resin, 3-6 parts; fluorocarbon surfactant, 3-5 parts; fluorosilicone modified resin, 15-20 parts; fluorinated ethylene propylene, 5-10 parts; antioxidant, 0.2-0.5 parts.

[0019] The polyethylene is high-density polyethylene with a molecular weight of 300,000-400,000 and a density ≥0.950 g / cm3.

[0020] The molecular weight of the polyvinylidene fluoride is 400,000-450,000.

[0021] The crosslinking agent is dicumyl peroxide.

[0022] The co-crosslinking agent is triallyl cyanurate. During the extrusion process of the composition, under the action of the crosslinking agent, polyethylene and fluorocarbon surfactant are firmly linked together by the co-crosslinking agent.

[0023] The EVA resin is an ethylene-vinyl acetate copolymer with a vinyl acetate content of ≤5%. EVA resin rapidly crosslinks polyethylene and increases the degree of crosslinking of polyethylene. Furthermore, EVA with low vinyl acetate content exhibits good compatibility with polyethylene.

[0024] The fluorocarbon surfactant is an ammonium oxide type multifunctional fluorocarbon surfactant, model INTECHEM-08 (FC-8), which has excellent anti-corrosion properties. Due to the presence of fluorine atoms in its molecule, it has good compatibility with polyvinylidene fluoride. Furthermore, it possesses antistatic properties, making it an excellent antistatic agent, and therefore does not generate static electricity upon contact with oil.

[0025] The fluorosilicone modified resin is a fluorosilicone modified organosilicon resin, model YS-1060, which has good acid resistance and heat resistance.

[0026] The fluorinated ethylene propylene is a copolymer of hexafluoropropylene and tetrafluoroethylene, and its melt processing temperature is not much different from that of high-density polyethylene, allowing it to be extruded using a general-purpose screw. Its addition not only acts as a compatibilizer, tightly binding polyvinylidene fluoride and polyethylene, but also works synergistically with the fluorosilicone-modified resin to further improve the acid resistance and strength of the composition.

[0027] The antioxidant is a mixture of hindered phenolic and phosphite antioxidants in a mass ratio of 1:1, preferably a mixture of hindered phenolic 1010 and phosphite 168.

[0028] The preparation method of the acid-resistant and antistatic polyethylene inner lining board composition of the present invention is as follows:

[0029] (1) Weigh out polyethylene, antioxidant, fluorocarbon surfactant, crosslinking agent, and crosslinking aid according to the formula ratio, put them into a high-speed mixer and mix at high speed for 5 minutes. Then release the material for later use.

[0030] (2) Put polyvinylidene fluoride, the material treated in step (1), EVA resin, fluorinated ethylene propylene, and fluorosilicone modified resin into a high-speed mixer and mix for 5-8 minutes. Then release the material to obtain the acid-resistant and antistatic polyethylene inner lining board composition of the present invention.

[0031] (3) The acid-resistant and antistatic composition of the present invention is subjected to reactive extrusion in a twin-screw extruder at a temperature of 180-230°C to obtain an acid-resistant and antistatic polyethylene inner liner.

[0032] The present invention has the following beneficial technical effects:

[0033] (1) Under the action of the crosslinking agent, polyethylene and fluorocarbon surfactant are tightly linked together by the crosslinking agent. The fluorocarbon surfactant is distributed in the polyethylene resin, which improves the permanent acid resistance, antistatic properties and strength of the composition.

[0034] (2) The addition of fluorinated ethylene propylene not only acts as a compatibilizer, tightly binding polyvinylidene fluoride and polyethylene, but also further improves the acid resistance and strength of the composition; it works synergistically with fluorosilicone modified resin, and because of the presence of fluorine, it further improves the acid resistance of the composition.

[0035] (3) The addition of EVA resin accelerates the cross-linking of polyethylene during the material extrusion process, improves the degree of cross-linking of polyethylene, and the low VA content EVA resin has good compatibility with polyethylene.

[0036] (4) The extruded sheet of the composition obtained by the present invention has excellent acid resistance, good antistatic properties, good flame retardancy, and high strength.

[0037] (5) The raw materials used in the composition of the present invention are readily available and the production process is mature, thus it has good application prospects. Detailed Implementation

[0038] To facilitate understanding of the present invention, various exemplary embodiments of the present invention are now described in detail. This detailed description should not be regarded as a specific limitation of the present invention, but should be understood as a more detailed description of certain aspects, features and embodiments of the present invention.

[0039] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0041] Table 1 lists the embodiments of the present invention, and Table 2 is a comparative example, wherein:

[0042] The polyethylene is high-density polyethylene with a molecular weight of 300,000-400,000 and a density ≥0.950 g / cm3, and is grade HDPE 1158 powder.

[0043] The polyvinylidene fluoride has a molecular weight of 400,000 and is produced by Inner Mongolia Sanai Fuwanhao Fluorochemical Co., Ltd.

[0044] The crosslinking agent is dicumyl peroxide;

[0045] The crosslinking agent is triallyl cyanurate;

[0046] The EVA resin is an ethylene vinyl acetate copolymer, with an EVA melt flow rate of 1 g / 10 min and a VA content of 4%.

[0047] The fluorocarbon surfactant is an ammonium oxide type multifunctional fluorocarbon surfactant, model INTECHEM-08(FC-8);

[0048] The fluorosilicone modified resin is a fluorosilicone modified organosilicon resin, model YS-1060;

[0049] The fluorinated ethylene propylene is a copolymer of hexafluoropropylene and tetrafluoroethylene. Its melt processing temperature is not much different from that of high-density polyethylene, and it can be extruded using a general-purpose screw.

[0050] The antioxidant is a mixture of hindered phenolic and phosphite antioxidants in a 1:1 mass ratio, specifically a mixture of hindered phenolic 1010 and phosphite 168.

[0051] Table 1 Formulation of embodiments of the present invention

[0052]

[0053]

[0054] The preparation method of the example is as follows:

[0055] (1) Weigh out polyethylene, antioxidant, fluorocarbon surfactant, crosslinking agent, and crosslinking aid according to the formula ratio, put them into a high-speed mixer and mix at high speed for 5 minutes. Then release the material for later use.

[0056] (2) Put polyvinylidene fluoride, the material processed in step (1), EVA resin, fluorinated ethylene propylene, and fluorosilicone modified resin into a high-speed mixer and mix for 6 minutes. Then release the material for later use.

[0057] (3) The well-mixed composition in step (2) is subjected to reactive extrusion in a twin-screw extruder at a temperature of 180-230°C to obtain an acid-resistant and antistatic polyethylene inner liner.

[0058] Table 2 shows the formulations of the comparative examples of the present invention, wherein:

[0059] Compared with Example 3, Comparative Example 1 did not use fluorocarbon surfactants, and the other components were the same; Comparative Example 2 did not add crosslinking agents and co-crosslinking agents, and the other components were the same; Comparative Example 3 did not add fluorosilicone modified resin, and the other components were the same; Comparative Example 4 did not add fluorinated ethylene propylene, and the other components were the same; Comparative Example 5 did not add EVA resin, and the other components were the same.

[0060] Table 2 Comparative formulations

[0061]

[0062]

[0063] The preparation method for the comparative example is as follows:

[0064] (1) Weigh each component according to the formula ratio, put them into a high-speed mixer and mix at high speed for 5 minutes. Then release the material for later use.

[0065] (2) The mixture prepared in step (1) is extruded in a twin-screw extruder at a temperature of 180-230°C to obtain a polyethylene inner liner.

[0066] Performance testing

[0067] The performance test results of the above embodiments and comparative examples are shown in Tables 3 and 4 below.

[0068] Table 3 Performance test results of the embodiments

[0069]

[0070] Note: Tensile strength was tested according to GB / T 1040-2006, using type 1A specimens, and sampled from the extruded sheet.

[0071] Table 4 Comparative Performance Test Results

[0072]

[0073]

[0074] Note: Tensile strength was tested according to GB / T 1040-2006, using type 1A specimens, and sampled from the extruded sheet.

[0075] The performance test results show that the performance of the examples is superior to that of the comparative examples, especially in acid resistance. After immersion in sulfuric acid for 30 days, the tensile strength remained essentially unchanged, indicating that the boards have good acid resistance. Furthermore, compared to the comparative examples, the examples exhibit better antistatic properties. Specifically, Comparative Example 1, lacking the addition of fluorocarbon surfactants, suffered a significant reduction in acid resistance, manifested in a marked decrease in tensile strength after sulfuric acid immersion and poor antistatic properties. Comparative Example 2, due to the lack of cross-linking during extrusion, experienced reduced tensile strength, which was also low after sulfuric acid immersion. Comparative Example 3, lacking the addition of fluorosilicone modified resin, showed a significant decrease in acid resistance, manifested in reduced strength after sulfuric acid immersion. Comparative Example 4, lacking the addition of fluorinated ethylene propylene, resulted in poor composition compatibility, leading to decreased strength and acid resistance. Comparative Example 5, lacking the addition of EVA resin, had a reduced degree of cross-linking, resulting in lower board strength and poorer acid resistance.

[0076] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A composition for an acid-resistant and antistatic polyethylene inner lining, characterized in that, The formula, by weight parts, includes: polyethylene, 60-80 parts; polyvinylidene fluoride, 15-30 parts; crosslinking agent, 0.5-1 part; co-crosslinking agent, 1-3 parts; fluorocarbon surfactant, 3-5 parts; fluorinated ethylene propylene, 5-10 parts; fluorosilicone modified resin, 15-20 parts. Wherein, the polyethylene is high-density polyethylene; the fluorocarbon surfactant is an ammonium oxide type multifunctional fluorocarbon surfactant; the crosslinking agent is triallyl cyanurate; and the fluorinated ethylene propylene is a copolymer of hexafluoropropylene and tetrafluoroethylene.

2. The acid-resistant and antistatic polyethylene liner composition as described in claim 1, characterized in that, It further contains 3-6 parts of EVA resin and 0.2-0.5 parts of antioxidant.

3. The acid-resistant and antistatic polyethylene liner composition as described in claim 2, characterized in that, The vinyl acetate content of the EVA resin is ≤5%; the antioxidant is a mixture of hindered phenolic and phosphite antioxidants in a mass ratio of 1:

1.

4. The method for preparing the acid-resistant and antistatic polyethylene liner composition as described in claim 2 or 3, characterized in that, The method includes the following steps: (1) Weigh out polyethylene, antioxidant, fluorocarbon surfactant, crosslinking agent and co-crosslinking agent according to the formula ratio, put them into a high-speed mixer and mix at high speed, then release the material for later use; (2) Put polyvinylidene fluoride, the material treated in step (1), EVA resin, fluorinated ethylene propylene, and fluorosilicone modified resin into a high-speed mixer and mix them. Then release the material to obtain an acid-resistant and antistatic polyethylene inner lining board composition. (3) The acid-resistant and antistatic composition is reactively extruded in a twin-screw extruder at a temperature of 180-230℃ to obtain an acid-resistant and antistatic polyethylene inner liner.

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